HCCI Hertiage Crystal Clean Inc

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Heritage-Crystal Clean, Inc., a Delaware corporation and its subsidiaries (collectively the “Company”), provide parts cleaning, used oil re-refining, hazardous and non-hazardous waste disposal, emergency and spill response, and industrial and field services to vehicle maintenance businesses, manufacturers and other industrial businesses, as well as utilities and governmental entities. The Company owns and operates a used oil re-refinery where it re-refines used oils and sells high quality base oil for use in the manufacture of finished lubricants as well as other re-refinery products. The Company also has multiple locations where it dehydrates used oil. The oil processed at these locations is primarily sold as recycled fuel oil. The Company also operates twelve non-hazardous waste processing facilities, as well as five antifreeze recycling facilities at which it produces virgin-quality antifreeze. The Company's locations are in the United States and Ontario, Canada. The Company conducts its primary business operations through Heritage-Crystal Clean, LLC, its wholly owned subsidiary, and all intercompany balances have been eliminated in consolidation.

Effective January 1, 2023, the Company revised its reportable segments as a result of the Patriot Environmental Services, Inc. acquisition. Previously we had two reportable segments: "Environmental Services," and "Oil Business." Under the revised segment presentation, the Company now has three reportable segments:

•"Environmental Services," which consists of the Company's parts cleaning, containerized hazardous and non-hazardous waste collection and hazardous waste disposal, wastewater vacuum, and antifreeze recycling activities. Product revenues include sales of solvent, machines, absorbent, accessories, and antifreeze; service revenues include servicing of parts cleaning machines, containerized hazardous and non-hazardous waste removal services, and wastewater vacuum services through the branch network. Rental income includes embedded lease income from certain parts cleaning contracts.

•"Oil Business," which consists of the Company's used oil collection, recycled fuel oil sales, used oil re-refining activities, and used oil filter removal and disposal services. Product revenues primarily consist of sales of re-refined base oil, re-refinery co-products and recycled fuel oil; service revenues include revenues from used oil collection activities, collecting and disposing of wastewater and removal and disposal of used oil filters.

•"Industrial and Field Services," which consists of the Company's industrial and field services and non-hazardous waste processing and includes revenues related to industrial and field services, emergency and spill response as well as processing of non-hazardous waste.

Due to the Company's integrated business model, it is impracticable to separately present costs of tangible products and costs of services.

No customer represented greater than 10% of consolidated revenues for any of the periods presented. Intercompany revenues have been eliminated. All segments operate in the United States and, to an immaterial degree, in Ontario, Canada. As such, the Company is not disclosing operating results by geographic segment.

Beginning with our 2023 fiscal year, we changed our financial reporting cycle to a calendar year-end and end-of-month quarterly reporting cycle. Accordingly, our 2023 fiscal year began on January 1, 2023 (the day after the end of the 2022 fiscal year) and will end on December 31, 2023, and our 2023 quarters include the three month periods ending March 31, June 30, September 30, and December 31. Prior to 2023, our fiscal year was a 52 or 53 week fiscal year that ended on the Saturday nearest to December 31, and our quarterly reporting cycle included twelve week periods for the first, second, and third quarters and a sixteen week period (or in some cases a seventeen week period) for the fourth quarter. We have not restated, and do not plan to restate, historical results.

The table below shows the reporting periods as we refer to them in this report, their date ranges, and the number of days in each:

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The Company's significant accounting policies are described in Note 2, "Summary of Significant Accounting Policies," in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022. You should read the condensed consolidated financial statements in conjunction with our consolidated financial statements and related notes in our Annual Report on Form 10-K filed with the SEC on March 1, 2023. There have been no material changes in these policies or their application during the second quarter of fiscal 2023 except for the fiscal year change as further described in Note 1.

In the opinion of management, all adjustments and disclosures necessary for the fair presentation of these interim statements have been included

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On August 3, 2022, Heritage-Crystal Clean, LLC, completed its acquisition of all of the capital stock of Patriot Environmental Services, Inc. ("Patriot"), a leading provider of environmental services across the Western United States specializing in emergency response, industrial services, OSRO spill response and a wide variety of waste services. Total consideration for the acquisition was approximately $156.9 million in cash subject to various adjustments such as a working capital adjustment and seller indemnification obligations. To date, there have been no adjustments to the purchase price. Goodwill recognized from the acquisition of Patriot, represents the excess of the estimated purchase consideration transferred over the estimated fair value of the assets acquired and liabilities assumed. The Company has not finalized the purchase price allocation for the acquisition as of June 30, 2023. The following balances of the purchase price allocation are subject to change as a result of any working capital adjustments and seller indemnification obligations: other current assets, goodwill, and accounts payable and accruals. Factors leading to goodwill being recognized are the Company’s expectation of synergies from combining operations of Patriot, and the Company as well as the value of intangible assets that are not separately recognized, such as the assembled workforce. Transaction costs incurred in conjunction with the acquisition of Patriot were approximately $1.2 million. The results of Patriot are consolidated into the Company’s Industrial and Field Services segment from the date of acquisition.

The following table summarizes the estimated fair values of the assets acquired, net of cash acquired, related to Patriot at the acquisition date:

(thousands)																					Patriot Environmental Services, Inc.(1)
Accounts receivable																					$	25,381
Other current assets																					2,034
Property, plant, & equipment																					33,968
Intangible assets																					62,200
Goodwill																					62,541
Accounts payable and accruals																					(12,929)
Deferred tax liabilities																					(16,313)
Total purchase price, net of cash acquired																					$	156,882
Less: placed in escrow																					2,780
Net cash paid																					$	154,102

(1) The Company is still in the process of finalizing the purchase price allocation for the acquisition and therefore the following balances are subject to change as a result of any working capital adjustments and seller indemnification obligations: other current assets, goodwill, and accounts payable and accruals.

Unaudited Pro Forma Financial Information

The pro forma financial information in the table below presents the combined results of the Company as if the Patriot acquisition had occurred on January 1, 2022. The pro forma information is shown for illustrative purposes only and is not

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necessarily indicative of future results of operations of the Company or results of operations of the Company that would have actually occurred had the transactions been in effect for the periods presented.

						Second Quarter Ended,
(thousands, except per share data)						June 30, 2023 (91 days)						June 18, 2022 (84 days)
Total revenues						$	192,166					$	184,361
Net income						$	8,642					$	21,065
Net income per share: basic						$	0.36					$	0.90
Net income per share: diluted						$	0.36					$	0.89

						First Half Ended,
(thousands, except per share data)						June 30, 2023 (181 days)						June 18, 2022 (168 days)
Total revenues						$	385,647					$	353,806
Net income						$	25,231					$	32,652
Net income per share: basic						$	1.07					$	1.39
Net income per share: diluted						$	1.06					$	1.38

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We account for a contract when it has approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance and collectability of consideration is probable. Revenue is recognized when our performance obligations under the terms of a contract with our customers are satisfied. Recognition occurs when the Company transfers control by completing the specified services at the point in time the customer benefits from the services performed or once our products are delivered. The majority of revenue is recognized at a point in time, except for rental income which is recognized on an over time basis. The Company measures progress toward complete satisfaction of a performance obligation satisfied over time using a cost-based input method. This method of measuring progress provides a faithful depiction of the transfer of goods or services because the costs incurred are expected to be substantially proportionate to the Company’s satisfaction of the performance obligation. Revenue is measured as the amount of consideration we expect to receive in exchange for completing our performance obligations. Sales tax and other taxes we collect with revenue-producing activities are excluded from revenue. In the case of contracts with multiple performance obligations, the Company allocates the transaction price to each performance obligation based on the relative stand-alone selling prices of the various goods and/or services encompassed by the contract. We do not have any material significant payment terms as payment is generally due within 30 days after the performance obligation has been satisfactorily completed. The Company has elected the practical expedient to recognize the incremental costs of obtaining a contract as an expense when incurred if the amortization period of the asset that we otherwise would have recognized is one year or less. In applying the guidance in Topic 606, there were no judgments or estimates made that the Company deems significant.

Contract Balances — Contract assets primarily relate to the Company’s rights to consideration for work completed in relation to its services performed but not billed at the reporting date. Contract liabilities primarily consist of advance payments of performance obligations yet to be fully satisfied in the period reported. Our contract liabilities and contract assets are reported in a net position at the end of each reporting period.

We disaggregate our revenue from contracts with customers by major lines of business for each of our segments, as we believe it best depicts how the nature, amount, timing and uncertainty of our revenue and cash flows are affected by economic factors. As further described in Note 10, prior period segment results presented for comparative purposes below have been recast to reflect the newly reportable segments.

The following table disaggregates our revenue by major lines:

									Second Quarter Ended,
									June 30, 2023 (91 days)																								June 18, 2022 (84 days)
Total Net Sales by Major Lines of Business (thousands)									Environmental Services						Oil Business						Industrial and Field Services						Total						Environmental Services						Oil Business						Industrial and Field Services						Total
Parts Cleaning, Containerized Waste, & related products/services									$	57,885					$	—					$	1,455					$	59,340					$	49,217					$	—					$	1,103					$	50,320
Vacuum Services & Wastewater Treatment									21,116						—						6,458						27,574						15,089						—						6,061						21,150
Industrial & Field Services									—						—						38,556						38,556						—						—						6,539						6,539
Antifreeze Business									8,439						—						—						8,439						7,118						—						—						7,118
Environmental Services - Other									453						—						—						453						486						—						—						486
Re-refinery Product Sales									—						41,820						—						41,820						—						54,198						—						54,198
Oil Collection Services & RFO									—						6,002						—						6,002						—						9,253						—						9,253
Oil Filter Business									—						1,299						—						1,299						—						1,309						—						1,309
Revenues from Contracts with Customers									87,893						49,121						46,469						183,483						71,910						64,760						13,703						150,373
Rental Income									8,072						11						600						8,683						6,265						9						—						6,274
Total Revenues									$	95,965					$	49,132					$	47,069					$	192,166					$	78,175					$	64,769					$	13,703					$	156,647

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												First Half Ended,
												June 30, 2023 (181 days)																								June 18, 2022 (168 days)
Total Net Sales by Major Lines of Business (thousands)												Environmental Services						Oil Business						Industrial and Field Services						Total						Environmental Services						Oil Business						Industrial and Field Services						Total
Parts cleaning, containerized waste, & related products/services												$	114,543					$	—					$	2,924					$	117,467					$	95,340					$	—					$	1,836					$	97,176
Wastewater Vacuum Services												41,460						—						12,883						54,343						28,397						—						10,144						38,541
Field Services												—						—						76,304						76,304						—						—						12,829						12,829
Antifreeze Business												18,115						—						—						18,115						14,774						—						—						14,774
Environmental Services - Other												975						—						—						975						981						—						—						981
Re-refinery Product Sales												—						88,629						—						88,629						—						103,337						—						103,337
Oil Collection Services & RFO												—						10,740						—						10,740						—						13,566						—						13,566
Oil Filter Business												—						2,702						—						2,702						—						2,558						—						2,558
Revenues from Contracts with Customers												175,093						102,071						92,111						369,275						139,492						119,461						24,809						283,762
Rental income												15,639						17						716						16,372						12,228						23						—						12,251
Total Revenues												$	190,732					$	102,088					$	92,827					$	385,647					$	151,720					$	119,484					$	24,809					$	296,013

The following table provides information about contract assets and contract liabilities from contracts with customers:

(thousands)									June 30, 2023						December 31, 2022
Contract assets									$	—					$	133
Contract liabilities									3,259						2,658
Contract liabilities - net									$	3,259					$	2,525

During the fiscal quarter ended June 30, 2023, the Company recognized no revenue that was included in the contract liabilities balance as of December 31, 2022. During the first half ended June 30, 2023, the Company recognized $2.5 million of revenue that was included in the contract liabilities balance as of December 31, 2022. The Company has no assets recognized from costs to obtain or fulfill a contract with a customer. We do not disclose the value of unsatisfied performance obligations for contracts with an original expected length of one year or less.

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Accounts Receivable — Net, includes amounts billed to and currently due from customers. The amounts due are stated at their net estimated realizable value. The allowance for uncollectible accounts is our best estimate of the amount of probable lifetime-expected credit losses in existing accounts receivable and is determined based on our historical collections experience, age of the receivable, knowledge of the customer and the condition of the general economy and industry as a whole. The Company does not have any off-balance-sheet credit exposure related to its customers.

Accounts receivable for the second quarter ended June 30, 2023, and the fiscal year ended December 31, 2022 consisted of the following:

(thousands)						June 30, 2023						December 31, 2022
Trade						$	105,263					$	111,118
Less: allowance for uncollectible accounts						5,527						4,496
Trade - net						99,736						106,622
Related parties						4,437						6,777
Other						531						1,009
Total accounts receivable - net						$	104,704					$	114,408

The following table provides the changes in the Company’s allowance for uncollectible accounts for the first half ended June 30, 2023, and the fiscal year ended December 31, 2022:

(thousands)						June 30, 2023						December 31, 2022
Balance at beginning of period						$	4,496					$	2,928
Provision for uncollectible accounts						1,270						2,269
Accounts written off, net of recoveries						(239)						(701)
Balance at end of period						$	5,527					$	4,496

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The carrying value of inventory consisted of the following:

(thousands)						June 30, 2023						December 31, 2022
Solvents and solutions						$	11,829					$	10,792
Used oil and processed oil						18,991						14,904
Machines						7,206						6,329
Drums and supplies						6,543						6,476
Other						2,910						2,666
Total inventory						47,479						41,167
Less: machine refurbishing reserve						455						440
Total inventory - net						$	47,024					$	40,727

 

Inventory consists primarily of used oil, processed oil, solvents and solutions, new and refurbished parts cleaning machines, drums and supplies, and other items. Inventories are valued at the lower of first-in, first-out (FIFO) cost or net realizable value, net of any reserves for excess, obsolete, or unsalable inventory. The Company monitors its inventory levels at each of its locations and evaluates inventories for excess or slow-moving items. If circumstances indicate the cost of inventories exceed their recoverable value, inventories are reduced to net realizable value. The Company had no inventory write downs during the second quarter and first half of fiscal 2023 or 2022.

Goodwill is measured as a residual amount as of the acquisition date, which in most cases results in measuring goodwill as an excess of the purchase consideration transferred plus the fair value of any noncontrolling interest in the acquiree over the fair value of the net assets acquired, including any contingent consideration. The Company tests goodwill for impairment annually in the fourth quarter and in interim periods if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. The Company's determination of fair value requires certain assumptions and estimates, such as margin expectations, market conditions, growth expectations, expected changes in working capital, etc., regarding expected future profitability and expected future cash flows. The Company reports and tests goodwill for impairment only in its Environmental Services and Industrial and Field Services reporting units. As further discussed in Note 10, December 31, 2022 numbers presented for comparative purposes below have been recast to reflect the newly reportable segments. The Company analyzed the relative fair values of each acquisition and assigned goodwill to the respective segment that the results of each acquisition are consolidated into.

The following table shows changes to our goodwill balances by segment from December 31, 2022 to June 30, 2023:

(thousands)												Environmental Services						Industrial and Field Services						Total
Goodwill at December 31, 2022
Gross carrying amount												$	37,650					$	74,586					$	112,236
Net book value at December 31, 2022												$	37,650					$	74,586					$	112,236
Goodwill at June 30, 2023
Gross carrying amount												37,650						74,586						$	112,236
Net book value at June 30, 2023												$	37,650					$	74,586					$	112,236

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The following is a summary of software and other intangible assets:

						June 30, 2023																		December 31, 2022
(thousands)						Gross Carrying Amount						Accumulated Amortization						Net Carrying Amount						Gross Carrying Amount						Accumulated Amortization						Net Carrying Amount
Customer & supplier relationships						$	62,268					$	28,655					$	33,613					$	62,268					$	25,762					$	36,506
Permits						60,690						4,577						56,113						60,690						2,697						57,993
Software						10,090						3,992						6,098						13,643						7,378						6,265
Non-compete agreements						4,413						3,799						614						4,421						3,665						756
Patents, formulae, and licenses						1,769						1,003						766						1,769						971						798
Other*						601						714						(113)						597						580						17
Total software and intangible assets						$	139,831					$	42,740					$	97,091					$	143,388					$	41,053					$	102,335

*Other intangibles include an above market lease acquired in September 2021 that had a fair value of ($0.7) million upon acquisition and is being accreted over the remaining useful life of the lease.

Amortization expense was $2.9 million for the second quarter ended June 30, 2023, and $1.4 million for the second quarter ended June 18, 2022. Amortization expense was $5.6 million for the first half ended June 30, 2023, and $2.8 million for the first half ended June 18, 2022.

The weighted average useful lives of software and other intangibles are as follows:

						Weighted Average Useful Life (years)
Permits						17
Patents, formulae, & licenses						15
Customer and supplier relationships						12
Software						9
Non-compete agreements						5
Other						7

    The estimated amortization expense for the remainder of fiscal 2023 and each of the five succeeding fiscal years is as follows:

(millions)
Fiscal Year						Amortization Expense
2023						$4.8
2024						8.5
2025						7.5
2026						7.0
2027						6.9
2028						6.8

The preceding expected amortization expense is an estimate. Actual amounts of amortization expense may differ from estimated amounts due to additional intangible asset acquisitions, the finalization of the fair value of intangible assets that have been acquired from business combinations, disposal of intangible assets, accelerated amortization of intangible assets, and other events.

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Accounts payable consisted of the following:

(thousands)						June 30, 2023						December 31, 2022
Accounts payable						$	51,763					$	54,935
Accounts payable - related parties						839						152
Total accounts payable						$	52,602					$	55,087

Bank Credit Facility

On March 18, 2021, Heritage-Crystal Clean, LLC, (the “Company”), entered into an Amended and Restated Credit Agreement (the "Agreement"), by and among the Company, its parent, Heritage-Crystal Clean, Inc., and the Company’s subsidiaries identified therein and Bank of America, N.A., as administrative agent, JPMorgan Chase Bank, N.A., and Wells Fargo Bank, National Association. The new Agreement provides for borrowings of up to $100.0 million, in the form of a revolving facility, of which $15 million can be used in the form of a Swing Line loan. The Agreement also provided for up to an additional $50.0 million of borrowings using an accordion feature upon approval of the lenders. On August 3, 2022, the Company entered into an Amendment (Amendment No. 1 to the Agreement "the Amendment") which increased the amount of borrowing under the revolving credit line to $150.0 million. The Company utilized the credit line to finance $115.0 million of the acquisition of Patriot Environmental Services Inc. (see Note 3). The Amendment also provides for up to an additional $50.0 million of borrowings under an accordion feature upon approval of the lenders.

Loans made under the Agreement, as amended, may be Base Rate Loans or Secured Overnight Financing Rate ("SOFR") Loans, at the election of the Borrower subject to certain exceptions. Base Rate Loans have an interest rate equal to (i) the higher of (a) the federal funds rate plus 0.5%, (b) the SOFR plus a margin of 1%, or (c) Bank of America's prime rate, plus a margin of 1.00%. SOFR rate loans have an interest rate equal to (i) the SOFR rate plus (ii) a variable margin of between 1.50% and 2.25% depending on the Company's total leverage ratio. Amounts borrowed under the Agreement are secured by a security interest in substantially all of the Company's tangible and intangible assets. In August 2022, the Company incurred an additional $0.1 million of debt issuance costs related to the amendment of the credit agreement and drawdown.

The Company's weighted average interest rate for all debt for the second quarter ended June 30, 2023 was 6.6%.

The Credit Agreement contains customary terms and provisions (including representations, covenants, and conditions) for transactions of this type. Certain covenants, among other things, restrict the Company's and its subsidiaries' ability to incur indebtedness, grant liens, make investments and sell assets. The Credit Agreement also contains customary events of default, covenants and representations and warranties. Financial covenants include:

•An interest coverage ratio (based on interest expense and EBITDA) of at least 3.5 to 1.0;

•A total leverage ratio no greater than 3.0 to 1.0, provided that in the event of a permitted acquisition having an aggregate consideration equal to $10.0 million or more, at the Borrower’s election, the foregoing 3.00 to 1.00 shall be deemed to be 3.50 to 1.00 for the fiscal quarter in which such permitted acquisition occurs and the three immediately following fiscal quarters and will thereafter revert to 3.00 to 1.00.

The Credit Agreement places certain limitations on acquisitions and the payment of dividends.

Long-term debt at June 30, 2023 and December 31, 2022 consisted of the following:

(thousands)						June 30, 2023						December 31, 2022
Long-term debt						$	85,000					$	90,000
Less: unamortized debt issuance costs						521						617
Long-term debt - net						$	84,479					$	89,383

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Effective January 1, 2023, the Company revised its reportable segments as a result of the Patriot Environmental Services, Inc. acquisition. Previously we had two reportable segments: "Environmental Services," and "Oil Business." Under the revised segment presentation, the Company now has three reportable segments: "Environmental Services," "Oil Business," and "Industrial and Field Services." The Environmental Services segment consists primarily of the Company's parts cleaning, containerized waste management, wastewater vacuum services, and antifreeze recycling activities. The Oil Business segment consists primarily of the Company's used oil collection, used oil re-refining activities, and the dehydration of used oil to be sold as recycled fuel oil. The Industrial and Field Services segment consists of the Company's industrial and field services, emergency and spill response services, as well as the activities at our non-hazardous waste processing facilities. Prior period segment results presented for comparative purposes below have been recast to reflect the newly reportable segment as a separate segment.

Segment results for the second quarter ended June 30, 2023 and June 18, 2022 were as follows:

Second Quarter Ended,
June 30, 2023 (91 days)
(thousands)									Environmental Services						Oil Business						Industrial and Field Services						Corporate and Eliminations						Consolidated
Revenues
			Service revenues						$	72,018					$	2,855					$	46,469					$	—					$	121,342
			Product revenues						15,875						46,266						—						—						62,141
			Rental income						8,072						11						600						—						8,683
Total revenues									$	95,965					$	49,132					$	47,069					$	—					$	192,166
Operating expenses
			Operating costs						68,459						40,781						37,147						—						146,387
			Operating depreciation and amortization						3,641						2,675						2,398						—						8,714
Profit before corporate selling, general, and administrative expenses									$	23,865					$	5,676					$	7,524					$	—					$	37,065
Selling, general, and administrative expenses																											20,361						20,361
Depreciation and amortization from SG&A																											3,088						3,088
Total selling, general, and administrative expenses																											$	23,449					$	23,449
Other (income) - net																											(265)						(265)
Operating income																																	13,881
Interest expense – net																											1,929						1,929
Income before income taxes																																	$	11,952

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First Half Ended,
June 18, 2022 (168 days)
(thousands)									Environmental Services						Oil Business						Industrial and Field Services						Corporate and Eliminations						Consolidated
Revenues
			Service revenues						$	114,479					$	5,212					$	24,809					$	—					$	144,500
			Product revenues						25,013						114,249						—						—						139,262
			Rental income						12,228						23						—						—						12,251
Total revenues									$	151,720					$	119,484					$	24,809					$	—					$	296,013
Operating expenses
			Operating costs						114,837						70,006						21,695						—						206,538
			Operating depreciation and amortization						5,236						4,209						845						—						10,290
Profit before corporate selling, general, and administrative expenses									$	31,647					$	45,269					$	2,269					$	—					$	79,185
Selling, general, and administrative expenses																											28,759						28,759
Depreciation and amortization from SG&A																											2,995						2,995
Total selling, general, and administrative expenses																											$	31,754					$	31,754
Other expense - net																											791						791
Operating income																																	46,640
Interest expense – net																											473						473
Income before income taxes																																	$	46,167

Intersegment revenues for the first half of fiscal 2023 and fiscal 2022 in the Industrial & Field services segment were $5.2 million and $3.9 million, respectively. The Environmental Services segment and the Oil Business segment had no intersegment revenues for the second quarter of fiscal 2023 and fiscal 2022.

Total assets by segment as of June 30, 2023 and December 31, 2022 were as follows:

(thousands)												June 30, 2023						December 31, 2022
Total Assets:
			Environmental Services									$	258,031					$	253,906
			Oil Business									186,153						190,862
			Industrial and Field Services									290,210						283,683
			Unallocated Corporate Assets									78,397						65,790
Total												$	812,791					$	794,241

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LEASES

Lessee

The Company leases buildings and property, railcars, machinery and equipment, and various types of vehicles and trailers for use in our operations. Each arrangement is evaluated individually to determine if the arrangement is or contains a lease at inception. The Company has lease agreements with lease and non-lease components and we have elected to not separate lease and non-lease components for all classes of underlying assets. In addition, our lease agreements do not contain any material residual guarantees or restrictive covenants.

Leases may include variable lease payments for common area maintenance, real estate taxes, and truck lease mileage. Variable lease payments are not included in the initial measurement of the right-of-use assets or lease liabilities, and are recorded as lease expense in the period incurred. Options to extend or terminate a lease are included in the lease term when it is reasonably certain that we will exercise that option. We have elected not to record leases with an initial term of 12 months or less on the balance sheet and instead recognize those lease payments on a straight-line basis over the lease term. Leases with initial terms in excess of 12 months are recorded as either operating or financing leases in our Consolidated Balance Sheet.

Right-of-use assets represent the Company's right to use an underlying asset during the lease term and lease liabilities represent the Company's obligation to make lease payments arising from the lease. Our leased right-of-use assets are measured at the initial measurement of the lease liability, adjusted for any lease payments made prior to the lease commencement date, less any lease incentives received and other initial direct costs incurred. Our lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As most of our leases do not provide an implicit rate, we use an incremental borrowing rate based on the information available at commencement date, including lease term, in determining the present value of future payments.

Our leases have remaining terms ranging from less than one month to approximately 11 years and may include options to extend or terminate the lease when it is reasonably certain that the option will be exercised. Lease expense is recognized on a straight-line basis over the lease term. Our finance leases include a fleet of mobile equipment.

Lessor

The Company is a lessor of portions of buildings and property, and equipment such as embedded leases of parts cleaning machines. Each of the Company’s leases is classified as an operating lease, and the vast majority are short-term leases. Variable lease payments include real and personal property taxes, which are based on the lessee’s pro rata portion of such amounts, and excess mileage charges which are computed as the actual miles traveled in a calendar year minus the maximum average mileage allowance as specified per the contract. Options to extend the lease beyond the original terms range from day-to-day renewals to increments of five-year extensions. Options to terminate the lease range from immediate termination upon return of the asset to various written notification periods following a minimum lease term. Options for a lessee to purchase the underlying asset are not contractually specified but may be negotiated on a case-by-case basis. Significant judgments made in determining whether a contract contains a lease include assessments as to whether or not the contract conveys the right to direct the use of an identified asset. Significant judgments made in allocating consideration between lease and non-lease components include techniques applied in estimating the relative stand-alone selling prices of the lease and non-lease components of the contract in cases where a stand-alone selling price is not directly observable. No leased assets are covered by residual value guarantees. The Company manages the risk associated with the residual value of leased assets through such means as performing periodic maintenance and upkeep activities and the inclusion of contractual terms that hold the lessee responsible for damage incurred to leased assets. The Company has made an accounting policy election to exclude from the consideration in the contract, and from variable payments not included in the consideration in the contract, all taxes assessed by a governmental authority that are both imposed on and concurrent with a specific lease revenue-producing transaction and collected by the lessor from a lessee.

The Company recognizes rental income on a straight-line basis for that portion of the consideration allocated to the embedded lease component of certain of our parts cleaning contracts. We also recognize rental income on certain subleases of portions of buildings and property.

Rental income was as follows:

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						Second Quarter Ended,
						June 30, 2023 (91 days)																								June 18, 2022 (84 days)
(thousands)						Environmental Services						Oil Business						Industrial and Field Services						Total						Environmental Services						Oil Business						Industrial and Field Services						Total
Parts Cleaning						$	7,968					$	—					$	600					$	8,568					$	6,233					$	—					$	—					$	6,233
Property						104						11						—						115						32						9						—						41
Total rental income						$	8,072					$	11					$	600					$	8,683					$	6,265					$	9					$	—					$	6,274

						First Half Ended,
						June 30, 2023 (181 days)																								June 18, 2022 (168 days)
(thousands)						Environmental Services						Oil Business						Industrial and Field Services						Total						Environmental Services						Oil Business						Industrial and Field Services						Total
Parts Cleaning						$	15,518					$	—					$	716					$	16,234					$	12,172					$	—					$	—					$	12,172
Property						121						17						—						138						56						23						—						79
Total rental income						$	15,639					$	17					$	716					$	16,372					$	12,228					$	23					$	—					$	12,251

Purchase Obligations

The Company may enter into purchase obligations with certain vendors. They represent expected payments to third party service providers and other commitments entered into during the normal course of our business. These purchase obligations are generally cancellable with or without notice, without penalty, although certain vendor agreements provide for cancellation fees or penalties depending on the terms of the contract.

The Company has purchase obligations in the form of open purchase orders of $21.3 million as of June 30, 2023, and $20.7 million as of December 31, 2022, primarily for used oil, solvent, machine purchases, disposal and transportation expenses, and capital expenditures.

Litigation and Claims

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Income tax expense for the second fiscal quarter of 2023 was $3.3 million. The Company's effective income tax rate for the second quarter of fiscal 2023 was 27.7% compared to 27.0% in the second quarter of fiscal 2022. Tax expense for the first half of 2023 was $8.9 million. The Company’s effective income tax rate for the first half of 2023 was 26.1% compared to 26.4% in the first half of 2022. The rate decrease is principally attributable to the increased impact of certain favorable adjustments to financial reporting income due to decreased levels of profitability as compared to the first half of fiscal 2022.

The Company establishes reserves when it is more likely than not that the Company will not realize the full tax benefit of a position. The Company had a reserve of $2.2 million for uncertain tax positions as of June 30, 2023. The gross unrecognized tax benefits would, if recognized, decrease the Company's effective tax rate.

As of June 30, 2023, the Company believes it is more likely than not that a benefit from foreign net operating loss carryforwards will not be realized. The Company provided a valuation allowance against those foreign net operating loss carryforwards of $0.7 million.

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 Restricted Stock Compensation/Awards

Annually, the Company grants restricted shares to its Board of Directors. The shares become fully vested one year from their grant date. The fair value of each restricted stock grant is based on the closing price of the Company's common stock on the date of grant. The Company amortizes the expense over the service period, which is the fiscal year in which the award is granted. In addition, the Company may grant restricted shares to certain members of management based on their services and contingent upon continued service with the Company. The restricted shares vest over a period of approximately three years from the grant date. The fair value of each restricted stock grant is based on the closing price of the Company's common stock on the date of grant.

On November 14, 2022, the Company granted 147,623 shares of restricted stock to certain members of Management as part of a Special Incentive Program. Up to 147,623 shares may vest on September 21, 2025. One-third of the shares vest in equal installments on each the first three anniversaries of September 21, 2022, subject to continuous employment or service with the Company through such date. Two-thirds of the shares are subject to the performance-based vesting terms based on the Company achieving certain Share Price Targets as set forth in the agreement during the three-year period beginning on September 21, 2022 (the “Performance Period”) and the Executive remaining employed by the Company through the Performance Period.

The following table shows a summary of restricted share grants and expense resulting from the awards:

    

																		Compensation Expense
(thousands, except share amounts)																		First Half Ended,												Unrecognized Expense as of,
Recipient of Grant						Grant Date						Restricted Shares						June 30, 2023 (181 days)						June 18, 2022 (168 days)						June 30, 2023 (181 days)						June 18, 2022 (168 days)
Special Incentive Grant						April, 2018						350,000						$	—					$	380					$	—					$	—
Members of Management						February, 2020						41,138						—						40						—						47
Members of Management						February, 2021						35,898						104						103						103						345
Chief Executive Officer						February, 2021						500,000						502						1,067						1,334						2,814
Members of Management						February, 2022						75,355						249						245						735						1,303
Members of Management						February, 2023						66,024						310						248						1,552						—
Board of Directors						April, 2022						17,082						—						234						—						246
Special Incentive Grant						November, 2022						147,623						524						—						2,339						—
Board of Directors						May, 2023						14,274						280						—						200						—

At June 30, 2023, there was $6.3 million of unrecognized stock-based compensation expense which is expected to be recognized over a weighted-average remaining vesting period of 1.7 years.

On January 8, 2021, the Company and Mr. Brian Recatto entered into an amended Executive Employment Agreement (the “Amended Agreement”) which was effective on February 1, 2021. Pursuant to the Amended Agreement, the Company replaced in its entirety section 4.3 of the First Amendment to the Executive Employment Agreement relating to equity compensation that was effective February 1, 2017. As of February 1, 2021, Mr. Recatto received a one-time award of 500,000 shares of restricted stock, subject to the achievement of performance criteria established by the Compensation Committee of the Board of Directors pursuant to the Company's 2019 Incentive Plan.

The award date for such Performance-Based Restricted Stock was on February 1, 2021. Such award was granted pursuant to and governed by the terms of the 2019 Incentive Plan and an award agreement in a form provided by the Company. The Performance-Based Restricted Stock one-time award of 500,000 shares received on February 1, 2021, shall vest on January 31, 2025 if Mr. Recatto is employed by the Company on that date, in an amount determined by applying the applicable percentages from the chart below, with the common stock price increases to be determined based on the increase in the price of the Company’s common stock (if any) from the closing price of the common stock as reported by Nasdaq on the amended agreement commencement date ($21.77) and the common stock price on the potential vesting date (determined by using the

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average closing price of a share of the Company's common stock for the 90-day period ending on the vesting date). If the stock price does not increase by $5.00, then no shares shall vest.

During the second quarter of fiscal 2023, the Company recorded approximately $0.2 million of compensation expense related to this award. In the future, the Company expects to recognize compensation expense of approximately $1.3 million over the remaining requisite service period, which ends January 31, 2025. The fair value of this restricted stock award as of the grant date was estimated using a Monte Carlo simulation model. Key assumptions used in the Monte Carlo simulation to estimate the grant date fair value of this award are a risk-free rate of 0.29%, expected dividend yield of zero, and an expected volatility assumption of 53.07%.

Vesting Table
Increase in Stock Price From the Amended Agreement Commencement Date to the Vesting Date						Total Percentage of Restricted Stock Shares to Be Vested
Less than $5 per share increase						—%
$5 per share increase						25% (vest in 125,000 shares)
$10 per share increase						50% (vest in 250,000 shares)
$15 per share increase						75% (vest in 375,000 shares)
$20 or more per share increase						100% (vest in 500,000 shares)

Provision for possible accelerated vesting of award

If the average closing price of the Company's common stock increases by the marginal levels set forth in the above vesting table for any consecutive 180 day period between February 1, 2021 and January 31, 2025, Mr. Recatto shall become vested in 50% of the corresponding total percentage of restricted shares earned on the last day of the 180 day period.

In addition, on each of December 31, 2021, December 31, 2022, and December 31, 2023, to the extent Mr. Recatto remains employed by the Company under the Amended Agreement on such date, Mr. Recatto shall receive a grant of restricted stock as of such date valued at Five Hundred Thousand Dollars ($500,000), with the number of shares of restricted stock constituting such grant determined by applying the average closing price for a share of the Company’s common stock for the 90-day period ending on such date. Such awards of Time-Based Restricted Stock shall be granted pursuant to and governed by the terms of the 2019 Incentive Plan and an award agreement in a form provided by the Company. The Time-Based Restricted Stock shall vest only if Mr. Recatto remains employed by the Company under the Amended Agreement through December 31, 2023; provided, that, upon a Change of Control of the Company (as such term is defined in the Amended Agreement), all shares of the Time-Based Restricted Stock awarded up through the date of closing of the Change in Control shall become vested, and no further award of Time-Based Restricted Stock shall be awarded. During the second quarter of fiscal 2023, the Company recorded approximately $0.1 million of compensation expense related to this award.

The following table summarizes the restricted stock activity for the second quarter ended June 30, 2023:

Restricted Stock (Nonvested Shares)						Number of Shares						Weighted Average Grant-Date Fair Value Per Share
Nonvested shares outstanding at December 31, 2022						728,693						$	21.83
Granted						80,298						37.08
Vested						(99,487)						25.51
Forfeited						(28,797)						21.95
Nonvested shares outstanding at June 30, 2023						680,707						$	25.79

Employee Stock Purchase Plan

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Recurring Fair Value Measurements

The following tables summarize assets measured at fair value on a recurring basis (in millions) as of June 30, 2023:

						Quoted prices in active markets (Level 1)						Significant other observable inputs (Level 2)						Significant unobservable inputs (Level 3)						Fair Value Measurements
Equity Securities (1)						$—						$—						$15.2						$15.2

On July 19, 2023, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) with JFL-Tiger Acquisition Co., Inc., a Delaware corporation (“Parent”), and JFL-Tiger Merger Sub, Inc., a Delaware corporation and wholly owned subsidiary of Parent (“Merger Sub”), pursuant to which, upon the terms and subject to the conditions set forth therein, Merger Sub will merge with and into the Company, with the Company surviving the merger as a wholly-owned subsidiary of Parent (the “Merger,” and together with the transactions contemplated by the Merger Agreement, the “Transaction”).

Pursuant to the Merger Agreement, at the effective time of the Merger (the “Effective Time”), each share of common stock of the Company then outstanding will be converted into the right to receive $45.50 in cash, without interest (the “Per Share Merger Consideration”), less any applicable withholding taxes, other than any shares as to which dissenters’ rights have been perfected (and not withdrawn or lost) in accordance with applicable law (which will be cancelled and converted into the right to receive a payment determined in accordance with Section 262 of the Delaware General Corporation Law).

The Merger Agreement also provides that immediately prior to the Effective Time, by virtue of the Merger and without any action on the part of the holder thereof (1) each outstanding Company restricted stock award will become fully vested and the restrictions with respect thereto will lapse, and all Company restricted stock awards will be treated in the Merger in the same manner as the other shares of Company Common Stock, and (2) each award of Company restricted stock units (“RSU”) that is outstanding immediately prior to the Effective Time will automatically be cancelled and converted into the right to receive a cash payment in an amount, without interest thereon and subject to applicable withholding taxes, equal to the product of (x) the

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Per Share Merger Consideration and (y) the total number of shares of common stock of the Company subject to such award of RSUs as of immediately prior to the Effective Time.

The obligations of the parties to consummate the Merger are subject to the satisfaction or waiver of customary closing conditions set forth in the Merger Agreement, including, among other conditions, (1) the adoption of the Merger Agreement by the affirmative vote of the stockholders of the Company of not less than 75% of the issued and outstanding shares of common stock of the Company (the “Company Stockholder Approval”), (2) the expiration or termination of any waiting period applicable under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and (3) the absence of a “Company Material Adverse Effect” (as defined in the Merger Agreement) with respect to the Company.

Each of the Company, Parent and Merger Sub has made customary representations and warranties and covenants in the Merger Agreement, including covenants to use their respective reasonable best efforts to effect the Transaction, including securing regulatory approvals required by the Merger Agreement. In addition, the Company has agreed to other customary covenants, including, among others, covenants to conduct its business in the ordinary course during the interim period between the execution of the Merger Agreement and the closing of the Merger.

The Merger Agreement contains customary termination rights for each of Parent and the Company, including, among others, if (1) the Merger has not been consummated by February 29, 2024 (the “End Date”), (2) the requisite Company Stockholder Approval is not obtained, (3) there is any order or applicable law prohibiting or permanently enjoining the Transaction or (4) the other party breaches its covenants or representations and such breach is not cured within a specified period and would result in the failure of a closing condition in favor of the other party. In addition, the Company may terminate the Merger Agreement in order for the board of directors of the Company to cause or permit the Company to enter into an Alternative Acquisition Agreement with respect to a Superior Proposal, and Parent may terminate the Merger Agreement if the board of directors of the Company changes its recommendation in favor of the Transaction. The Merger Agreement further provides that, upon termination of the Merger Agreement under certain specified circumstances, the Company will be required to pay Parent a termination fee of $42,331,515 (except in the case the Merger Agreement is terminated in connection with a Superior Proposal during the Go-Shop Period, and certain other limited circumstances, in which case such termination fee will be $23,584,701), or Parent will be required to pay the Company a termination fee of $72,568,311 (the “Parent Termination Fee”).

The Merger is not subject to a financing condition. Parent has obtained (1) equity financing commitments from certain investment affiliates of J.F. Lehman & Company, LLC (“JFLCO”) and certain investment affiliates of HarbourVest Partners, and (2) debt financing commitments from certain third-party lenders, to fund the transactions contemplated by the Merger Agreement. The Merger Agreement requires Parent to use its reasonable best efforts to obtain the financing on the terms and conditions described in the financing commitments. The Company is entitled to specific performance, subject to the terms and conditions of the Merger Agreement and the applicable equity commitments, to force Parent to close the transaction if all closing conditions are met.

In addition, an investment affiliate of JFLCO has also provided a limited guarantee in favor of the Company (the “Limited Guarantee”) with respect to certain obligations of Parent and Merger Sub under the Merger Agreement, including a guarantee of payment of the Parent Termination Fee and certain other reimbursement obligations that may be owed by Parent pursuant to the Merger Agreement.

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v3.23.2

Cover - shares	6 Months Ended
	Jun. 30, 2023	Aug. 08, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2023
Document Transition Report	false
Entity File Number	001-33987
Entity Registrant Name	HERITAGE-CRYSTAL CLEAN, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-0351454
Entity Address, Address Line One	2000 Center Drive
Entity Address, Address Line Two	Suite East C300
Entity Address, City or Town	Hoffman Estates
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60192
City Area Code	847
Local Phone Number	836-5670
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	HCCI
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		24,370,405
Entity Central Index Key	0001403431
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q2
Amendment Flag	false

v3.23.2

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 33,100	$ 22,053
Accounts receivable - net	104,704	114,408
Inventory - net	47,024	40,727
Assets held for sale	0	1,125
Other current assets	14,652	12,989
Total current assets	199,480	191,302
Property, plant and equipment - net	232,318	222,942
Right of use assets	126,290	123,742
Equipment at customers - net	30,157	26,465
Software and intangible assets - net	97,091	102,335
Goodwill	112,236	112,236
Other assets	15,219	15,219
Total assets	812,791	794,241
Current liabilities:
Accounts payable	52,602	55,087
Current portion of lease liabilities	28,490	27,277
Contract liabilities - net	3,259	2,525
Accrued salaries, wages, and benefits	9,339	12,443
Taxes payable	3,211	6,037
Other current liabilities	10,553	12,382
Total current liabilities	107,454	115,751
Lease liabilities, net of current portion	103,426	100,738
Other long term liabilities	770	986
Long-term debt - net	84,479	89,383
Deferred income taxes	60,765	57,155
Total liabilities	356,894	364,013
STOCKHOLDERS' EQUITY:
Common stock - 36,000,000 shares authorized at $0.01 par value, 23,687,649 and 23,593,163 shares issued and outstanding at June 30, 2023 and December 31, 2022, respectively	237	236
Additional paid-in capital	208,913	208,533
Retained earnings	247,057	221,826
Accumulated other comprehensive loss	(310)	(367)
Total stockholders' equity	455,897	430,228
Total liabilities and stockholders' equity	$ 812,791	$ 794,241

v3.23.2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Common stock, shares authorized (in shares)	36,000,000	36,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares issued (in shares)	23,687,649	23,593,163
Common stock, shares outstanding (in shares)	23,687,649	23,593,163

v3.23.2

Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 18, 2022	Jun. 30, 2023	Jun. 18, 2022
Revenues
Revenues	$ 183,483	$ 150,373	$ 369,275	$ 283,762
Rental income	8,683	6,274	16,372	12,251
Total revenues	192,166	156,647	385,647	296,013
Operating expenses
Operating costs	146,387	104,755	286,448	206,538
Selling, general, and administrative expenses	20,361	15,024	38,061	28,759
Depreciation and amortization	11,802	6,777	23,969	13,285
Other (income) expense - net	(265)	1,001	(734)	791
Operating income	13,881	29,090	37,903	46,640
Interest expense – net	1,929	250	3,743	473
Income before income taxes	11,952	28,840	34,160	46,167
Provision for income taxes	3,310	7,733	8,929	12,182
Net income	$ 8,642	$ 21,107	$ 25,231	$ 33,985
Net income per share: basic (in dollars per share)	$ 0.36	$ 0.90	$ 1.07	$ 1.45
Net income per share: diluted (in dollars per share)	$ 0.36	$ 0.89	$ 1.06	$ 1.44
Number of weighted average shares outstanding: basic (in shares)	23,681	23,489	23,665	23,482
Number of weighted average shares outstanding: diluted (in shares)	23,931	23,644	23,898	23,640
Service revenues
Revenues
Revenues	$ 121,342	$ 75,584	$ 240,794	$ 144,500
Product revenues
Revenues
Revenues	$ 62,141	$ 74,789	$ 128,481	$ 139,262

v3.23.2

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 18, 2022	Jun. 30, 2023	Jun. 18, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 8,642	$ 21,107	$ 25,231	$ 33,985
Other comprehensive income:
Currency translation adjustments	54	(121)	57	(75)
Total other comprehensive income (loss):	54	(121)	57	(75)
Comprehensive income	$ 8,696	$ 20,986	$ 25,288	$ 33,910

v3.23.2

Condensed Consolidated Statement of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid–in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning balance (in shares) at Jan. 01, 2022		23,473,931
Beginning balance at Jan. 01, 2022	$ 342,056	$ 235	$ 204,920	$ 137,067	$ (166)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	33,985			33,985
Currency translation adjustment	(75)				(75)
Issuance of common stock – ESPP (in shares)		8,627
Issuance of common stock – ESPP	251		251
Share-based compensation (in shares)		11,487
Share-based compensation	2,527		2,527
Share repurchases to satisfy tax withholding obligations	(1,402)		(1,402)
Ending balance (in shares) at Jun. 18, 2022		23,494,045
Ending balance at Jun. 18, 2022	377,342	$ 235	206,296	171,052	(241)
Beginning balance (in shares) at Mar. 26, 2022		23,477,764
Beginning balance at Mar. 26, 2022	356,450	$ 235	206,390	149,945	(120)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	21,107			21,107
Currency translation adjustment	(121)				(121)
Issuance of common stock – ESPP (in shares)		4,794
Issuance of common stock – ESPP	134		134
Share-based compensation (in shares)		11,487
Share-based compensation	1,174		1,174
Share repurchases to satisfy tax withholding obligations	(1,402)		(1,402)
Ending balance (in shares) at Jun. 18, 2022		23,494,045
Ending balance at Jun. 18, 2022	$ 377,342	$ 235	206,296	171,052	(241)
Beginning balance (in shares) at Dec. 31, 2022	23,593,163	23,593,163
Beginning balance at Dec. 31, 2022	$ 430,228	$ 236	208,533	221,826	(367)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	25,231			25,231
Currency translation adjustment	57				57
Issuance of common stock – ESPP (in shares)		9,845
Issuance of common stock – ESPP	318		318
Share-based compensation (in shares)		84,641
Share-based compensation	2,198	$ 1	2,197
Share repurchases to satisfy tax withholding obligations	$ (2,135)		(2,135)
Ending balance (in shares) at Jun. 30, 2023	23,687,649	23,687,649
Ending balance at Jun. 30, 2023	$ 455,897	$ 237	208,913	247,057	(310)
Beginning balance (in shares) at Mar. 31, 2023		23,664,515
Beginning balance at Mar. 31, 2023	445,961	$ 237	207,673	238,415	(364)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	8,642			8,642
Currency translation adjustment	54				54
Issuance of common stock – ESPP (in shares)		5,070
Issuance of common stock – ESPP	170		170
Share-based compensation (in shares)		18,064
Share-based compensation	$ 1,070		1,070
Ending balance (in shares) at Jun. 30, 2023	23,687,649	23,687,649
Ending balance at Jun. 30, 2023	$ 455,897	$ 237	$ 208,913	$ 247,057	$ (310)

v3.23.2

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 18, 2022	Jun. 30, 2023	Jun. 18, 2022	Dec. 31, 2022
Cash flows from Operating Activities:
Net income	$ 8,642	$ 21,107	$ 25,231	$ 33,985
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	11,802	6,777	23,969	13,285
Provision for civil action settlement			0	750
Uncollectible provision			1,270	453	$ 2,269
Share-based compensation			2,455	2,785
Deferred taxes			3,610	944
Other, net			(10)	1,099
Changes in operating assets and liabilities:
Decrease (increase) in accounts receivable			8,434	(18,207)
(Increase) in inventory			(6,297)	(6,685)
Decrease (increase) in other current assets			(538)	2,345
(Decrease) increase in accounts payable			(3,462)	8,091
(Decrease) increase in accrued liabilities			(7,823)	323
Cash provided by operating activities			46,839	39,168
Cash flows from Investing Activities:
Capital expenditures			(26,899)	(15,936)
Proceeds from sale of assets			1,578	96
Investment in Retriev			0	(3,000)
Cash used in investing activities			(25,321)	(18,840)
Cash flows from Financing Activities:
Credit line utilized			(5,000)	0
Repayment of principal on finance leases			(3,654)	(1,686)
Share repurchases to satisfy tax withholding obligations			(2,135)	(1,402)
Proceeds from the issuance of common stock			318	251
Cash used in financing activities			(10,471)	(2,837)
Net increase in cash and cash equivalents			11,047	17,491
Cash and cash equivalents, beginning of period			22,053	56,269	56,269
Cash and cash equivalents, end of period	$ 33,100	$ 73,760	33,100	73,760	$ 22,053
Supplemental disclosure of cash flow information:
Income taxes paid			9,683	11,796
Cash paid for interest			3,558	140
Supplemental disclosure of non-cash information:
Payables for construction in progress			$ 1,926	$ 874

v3.23.2

ORGANIZATION AND NATURE OF OPERATIONS	6 Months Ended
	Jun. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
ORGANIZATION AND NATURE OF OPERATIONS	ORGANIZATION AND NATURE OF OPERATIONS Heritage-Crystal Clean, Inc., a Delaware corporation and its subsidiaries (collectively the “Company”), provide parts cleaning, used oil re-refining, hazardous and non-hazardous waste disposal, emergency and spill response, and industrial and field services to vehicle maintenance businesses, manufacturers and other industrial businesses, as well as utilities and governmental entities. The Company owns and operates a used oil re-refinery where it re-refines used oils and sells high quality base oil for use in the manufacture of finished lubricants as well as other re-refinery products. The Company also has multiple locations where it dehydrates used oil. The oil processed at these locations is primarily sold as recycled fuel oil. The Company also operates twelve non-hazardous waste processing facilities, as well as five antifreeze recycling facilities at which it produces virgin-quality antifreeze. The Company's locations are in the United States and Ontario, Canada. The Company conducts its primary business operations through Heritage-Crystal Clean, LLC, its wholly owned subsidiary, and all intercompany balances have been eliminated in consolidation. Effective January 1, 2023, the Company revised its reportable segments as a result of the Patriot Environmental Services, Inc. acquisition. Previously we had two reportable segments: "Environmental Services," and "Oil Business." Under the revised segment presentation, the Company now has three reportable segments: •"Environmental Services," which consists of the Company's parts cleaning, containerized hazardous and non-hazardous waste collection and hazardous waste disposal, wastewater vacuum, and antifreeze recycling activities. Product revenues include sales of solvent, machines, absorbent, accessories, and antifreeze; service revenues include servicing of parts cleaning machines, containerized hazardous and non-hazardous waste removal services, and wastewater vacuum services through the branch network. Rental income includes embedded lease income from certain parts cleaning contracts. •"Oil Business," which consists of the Company's used oil collection, recycled fuel oil sales, used oil re-refining activities, and used oil filter removal and disposal services. Product revenues primarily consist of sales of re-refined base oil, re-refinery co-products and recycled fuel oil; service revenues include revenues from used oil collection activities, collecting and disposing of wastewater and removal and disposal of used oil filters. •"Industrial and Field Services," which consists of the Company's industrial and field services and non-hazardous waste processing and includes revenues related to industrial and field services, emergency and spill response as well as processing of non-hazardous waste. Due to the Company's integrated business model, it is impracticable to separately present costs of tangible products and costs of services. No customer represented greater than 10% of consolidated revenues for any of the periods presented. Intercompany revenues have been eliminated. All segments operate in the United States and, to an immaterial degree, in Ontario, Canada. As such, the Company is not disclosing operating results by geographic segment. Beginning with our 2023 fiscal year, we changed our financial reporting cycle to a calendar year-end and end-of-month quarterly reporting cycle. Accordingly, our 2023 fiscal year began on January 1, 2023 (the day after the end of the 2022 fiscal year) and will end on December 31, 2023, and our 2023 quarters include the three month periods ending March 31, June 30, September 30, and December 31. Prior to 2023, our fiscal year was a 52 or 53 week fiscal year that ended on the Saturday nearest to December 31, and our quarterly reporting cycle included twelve week periods for the first, second, and third quarters and a sixteen week period (or in some cases a seventeen week period) for the fourth quarter. We have not restated, and do not plan to restate, historical results. The table below shows the reporting periods as we refer to them in this report, their date ranges, and the number of days in each: Reporting Period Date Range Number of Days 2023 second quarter April 1, 2023 - June 30, 2023 91 2022 second quarter March 27, 2022 - June 18, 2022 84 2023 first half January 1, 2023 - June 30, 2023 181 2022 first half January 2, 2022 - June 18, 2022 168 2023 fiscal year January 1, 2023 - December 31, 2023 365 2022 fiscal year January 2, 2022 - December 31, 2022 364 As a result of the change in our financial reporting cycle, our 2023 second quarter and 2023 first half had 7 and 13 more calendar days of activity, respectively, than our 2022 second quarter and 2022 first half, respectively. While our 2023 full fiscal year will have one additional day of activity as compared to our 2022 full fiscal year, our 2023 fourth quarter will have 20 fewer days of activity than the corresponding period in our 2022 fiscal year.

v3.23.2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	6 Months Ended
	Jun. 30, 2023
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES The Company's significant accounting policies are described in Note 2, "Summary of Significant Accounting Policies," in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022. You should read the condensed consolidated financial statements in conjunction with our consolidated financial statements and related notes in our Annual Report on Form 10-K filed with the SEC on March 1, 2023. There have been no material changes in these policies or their application during the second quarter of fiscal 2023 except for the fiscal year change as further described in Note 1. In the opinion of management, all adjustments and disclosures necessary for the fair presentation of these interim statements have been included

v3.23.2

BUSINESS COMBINATIONS	6 Months Ended
	Jun. 30, 2023
Business Combination and Asset Acquisition [Abstract]
BUSINESS COMBINATIONS	BUSINESS COMBINATIONS On August 3, 2022, Heritage-Crystal Clean, LLC, completed its acquisition of all of the capital stock of Patriot Environmental Services, Inc. ("Patriot"), a leading provider of environmental services across the Western United States specializing in emergency response, industrial services, OSRO spill response and a wide variety of waste services. Total consideration for the acquisition was approximately $156.9 million in cash subject to various adjustments such as a working capital adjustment and seller indemnification obligations. To date, there have been no adjustments to the purchase price. Goodwill recognized from the acquisition of Patriot, represents the excess of the estimated purchase consideration transferred over the estimated fair value of the assets acquired and liabilities assumed. The Company has not finalized the purchase price allocation for the acquisition as of June 30, 2023. The following balances of the purchase price allocation are subject to change as a result of any working capital adjustments and seller indemnification obligations: other current assets, goodwill, and accounts payable and accruals. Factors leading to goodwill being recognized are the Company’s expectation of synergies from combining operations of Patriot, and the Company as well as the value of intangible assets that are not separately recognized, such as the assembled workforce. Transaction costs incurred in conjunction with the acquisition of Patriot were approximately $1.2 million. The results of Patriot are consolidated into the Company’s Industrial and Field Services segment from the date of acquisition. The following table summarizes the estimated fair values of the assets acquired, net of cash acquired, related to Patriot at the acquisition date: (thousands) Patriot Environmental Services, Inc.(1) Accounts receivable $ 25,381  Other current assets 2,034  Property, plant, & equipment 33,968  Intangible assets 62,200  Goodwill 62,541  Accounts payable and accruals (12,929) Deferred tax liabilities (16,313) Total purchase price, net of cash acquired $ 156,882  Less: placed in escrow 2,780  Net cash paid $ 154,102  (1) The Company is still in the process of finalizing the purchase price allocation for the acquisition and therefore the following balances are subject to change as a result of any working capital adjustments and seller indemnification obligations: other current assets, goodwill, and accounts payable and accruals. Unaudited Pro Forma Financial Information The pro forma financial information in the table below presents the combined results of the Company as if the Patriot acquisition had occurred on January 1, 2022. The pro forma information is shown for illustrative purposes only and is not necessarily indicative of future results of operations of the Company or results of operations of the Company that would have actually occurred had the transactions been in effect for the periods presented. Second Quarter Ended, (thousands, except per share data) June 30, 2023 (91 days) June 18, 2022 (84 days) Total revenues $ 192,166  $ 184,361  Net income $ 8,642  $ 21,065  Net income per share: basic $ 0.36  $ 0.90  Net income per share: diluted $ 0.36  $ 0.89  First Half Ended, (thousands, except per share data) June 30, 2023 (181 days) June 18, 2022 (168 days) Total revenues $ 385,647  $ 353,806  Net income $ 25,231  $ 32,652  Net income per share: basic $ 1.07  $ 1.39  Net income per share: diluted $ 1.06  $ 1.38

v3.23.2

REVENUE	6 Months Ended
	Jun. 30, 2023
Revenue from Contract with Customer [Abstract]
REVENUE	REVENUE We account for a contract when it has approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance and collectability of consideration is probable. Revenue is recognized when our performance obligations under the terms of a contract with our customers are satisfied. Recognition occurs when the Company transfers control by completing the specified services at the point in time the customer benefits from the services performed or once our products are delivered. The majority of revenue is recognized at a point in time, except for rental income which is recognized on an over time basis. The Company measures progress toward complete satisfaction of a performance obligation satisfied over time using a cost-based input method. This method of measuring progress provides a faithful depiction of the transfer of goods or services because the costs incurred are expected to be substantially proportionate to the Company’s satisfaction of the performance obligation. Revenue is measured as the amount of consideration we expect to receive in exchange for completing our performance obligations. Sales tax and other taxes we collect with revenue-producing activities are excluded from revenue. In the case of contracts with multiple performance obligations, the Company allocates the transaction price to each performance obligation based on the relative stand-alone selling prices of the various goods and/or services encompassed by the contract. We do not have any material significant payment terms as payment is generally due within 30 days after the performance obligation has been satisfactorily completed. The Company has elected the practical expedient to recognize the incremental costs of obtaining a contract as an expense when incurred if the amortization period of the asset that we otherwise would have recognized is one year or less. In applying the guidance in Topic 606, there were no judgments or estimates made that the Company deems significant. Contract Balances — Contract assets primarily relate to the Company’s rights to consideration for work completed in relation to its services performed but not billed at the reporting date. Contract liabilities primarily consist of advance payments of performance obligations yet to be fully satisfied in the period reported. Our contract liabilities and contract assets are reported in a net position at the end of each reporting period. We disaggregate our revenue from contracts with customers by major lines of business for each of our segments, as we believe it best depicts how the nature, amount, timing and uncertainty of our revenue and cash flows are affected by economic factors. As further described in Note 10, prior period segment results presented for comparative purposes below have been recast to reflect the newly reportable segments. The following table disaggregates our revenue by major lines: Second Quarter Ended, June 30, 2023 (91 days) June 18, 2022 (84 days) Total Net Sales by Major Lines of Business (thousands) Environmental Services Oil Business Industrial and Field Services Total Environmental Services Oil Business Industrial and Field Services Total Parts Cleaning, Containerized Waste, & related products/services $ 57,885  $ —  $ 1,455  $ 59,340  $ 49,217  $ —  $ 1,103  $ 50,320  Vacuum Services & Wastewater Treatment 21,116  —  6,458  27,574  15,089  —  6,061  21,150  Industrial & Field Services —  —  38,556  38,556  —  —  6,539  6,539  Antifreeze Business 8,439  —  —  8,439  7,118  —  —  7,118  Environmental Services - Other 453  —  —  453  486  —  —  486  Re-refinery Product Sales —  41,820  —  41,820  —  54,198  —  54,198  Oil Collection Services & RFO —  6,002  —  6,002  —  9,253  —  9,253  Oil Filter Business —  1,299  —  1,299  —  1,309  —  1,309  Revenues from Contracts with Customers 87,893  49,121  46,469  183,483  71,910  64,760  13,703  150,373  Rental Income 8,072  11  600  8,683  6,265  9  —  6,274  Total Revenues $ 95,965  $ 49,132  $ 47,069  $ 192,166  $ 78,175  $ 64,769  $ 13,703  $ 156,647  First Half Ended, June 30, 2023 (181 days) June 18, 2022 (168 days) Total Net Sales by Major Lines of Business (thousands) Environmental Services Oil Business Industrial and Field Services Total Environmental Services Oil Business Industrial and Field Services Total Parts cleaning, containerized waste, & related products/services $ 114,543  $ —  $ 2,924  $ 117,467  $ 95,340  $ —  $ 1,836  $ 97,176  Wastewater Vacuum Services 41,460  —  12,883  54,343  28,397  —  10,144  38,541  Field Services —  —  76,304  76,304  —  —  12,829  12,829  Antifreeze Business 18,115  —  —  18,115  14,774  —  —  14,774  Environmental Services - Other 975  —  —  975  981  —  —  981  Re-refinery Product Sales —  88,629  —  88,629  —  103,337  —  103,337  Oil Collection Services & RFO —  10,740  —  10,740  —  13,566  —  13,566  Oil Filter Business —  2,702  —  2,702  —  2,558  —  2,558  Revenues from Contracts with Customers 175,093  102,071  92,111  369,275  139,492  119,461  24,809  283,762  Rental income 15,639  17  716  16,372  12,228  23  —  12,251  Total Revenues $ 190,732  $ 102,088  $ 92,827  $ 385,647  $ 151,720  $ 119,484  $ 24,809  $ 296,013  The following table provides information about contract assets and contract liabilities from contracts with customers: (thousands) June 30, 2023 December 31, 2022 Contract assets $ —  $ 133  Contract liabilities 3,259  2,658  Contract liabilities - net $ 3,259  $ 2,525  During the fiscal quarter ended June 30, 2023, the Company recognized no revenue that was included in the contract liabilities balance as of December 31, 2022. During the first half ended June 30, 2023, the Company recognized $2.5 million of revenue that was included in the contract liabilities balance as of December 31, 2022. The Company has no assets recognized from costs to obtain or fulfill a contract with a customer. We do not disclose the value of unsatisfied performance obligations for contracts with an original expected length of one year or less.

v3.23.2

ACCOUNTS RECEIVABLE	6 Months Ended
	Jun. 30, 2023
Accounts Receivable, after Allowance for Credit Loss [Abstract]
ACCOUNTS RECEIVABLE	ACCOUNTS RECEIVABLE Accounts Receivable — Net, includes amounts billed to and currently due from customers. The amounts due are stated at their net estimated realizable value. The allowance for uncollectible accounts is our best estimate of the amount of probable lifetime-expected credit losses in existing accounts receivable and is determined based on our historical collections experience, age of the receivable, knowledge of the customer and the condition of the general economy and industry as a whole. The Company does not have any off-balance-sheet credit exposure related to its customers. Accounts receivable for the second quarter ended June 30, 2023, and the fiscal year ended December 31, 2022 consisted of the following: (thousands) June 30, 2023 December 31, 2022 Trade $ 105,263  $ 111,118  Less: allowance for uncollectible accounts 5,527  4,496  Trade - net 99,736  106,622  Related parties 4,437  6,777  Other 531  1,009  Total accounts receivable - net $ 104,704  $ 114,408  The following table provides the changes in the Company’s allowance for uncollectible accounts for the first half ended June 30, 2023, and the fiscal year ended December 31, 2022: (thousands) June 30, 2023 December 31, 2022 Balance at beginning of period $ 4,496  $ 2,928  Provision for uncollectible accounts 1,270  2,269  Accounts written off, net of recoveries (239) (701) Balance at end of period $ 5,527  $ 4,496

v3.23.2

INVENTORY	6 Months Ended
	Jun. 30, 2023
Inventory Disclosure [Abstract]
INVENTORY	INVENTORY The carrying value of inventory consisted of the following:  (thousands) June 30, 2023 December 31, 2022 Solvents and solutions $ 11,829  $ 10,792  Used oil and processed oil 18,991  14,904  Machines 7,206  6,329  Drums and supplies 6,543  6,476  Other 2,910  2,666  Total inventory 47,479  41,167  Less: machine refurbishing reserve 455  440  Total inventory - net $ 47,024  $ 40,727    Inventory consists primarily of used oil, processed oil, solvents and solutions, new and refurbished parts cleaning machines, drums and supplies, and other items. Inventories are valued at the lower of first-in, first-out (FIFO) cost or net realizable value, net of any reserves for excess, obsolete, or unsalable inventory. The Company monitors its inventory levels at each of its locations and evaluates inventories for excess or slow-moving items. If circumstances indicate the cost of inventories exceed their recoverable value, inventories are reduced to net realizable value. The Company had no inventory write downs during the second quarter and first half of fiscal 2023 or 2022.

v3.23.2

GOODWILL AND OTHER INTANGIBLE ASSETS	6 Months Ended
	Jun. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND OTHER INTANGIBLE ASSETS	GOODWILL AND OTHER INTANGIBLE ASSETS Goodwill is measured as a residual amount as of the acquisition date, which in most cases results in measuring goodwill as an excess of the purchase consideration transferred plus the fair value of any noncontrolling interest in the acquiree over the fair value of the net assets acquired, including any contingent consideration. The Company tests goodwill for impairment annually in the fourth quarter and in interim periods if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. The Company's determination of fair value requires certain assumptions and estimates, such as margin expectations, market conditions, growth expectations, expected changes in working capital, etc., regarding expected future profitability and expected future cash flows. The Company reports and tests goodwill for impairment only in its Environmental Services and Industrial and Field Services reporting units. As further discussed in Note 10, December 31, 2022 numbers presented for comparative purposes below have been recast to reflect the newly reportable segments. The Company analyzed the relative fair values of each acquisition and assigned goodwill to the respective segment that the results of each acquisition are consolidated into. The following table shows changes to our goodwill balances by segment from December 31, 2022 to June 30, 2023: (thousands) Environmental Services Industrial and Field Services Total Goodwill at December 31, 2022     Gross carrying amount $ 37,650  $ 74,586  $ 112,236  Net book value at December 31, 2022 $ 37,650  $ 74,586  $ 112,236  Goodwill at June 30, 2023      Gross carrying amount 37,650  74,586  $ 112,236  Net book value at June 30, 2023 $ 37,650  $ 74,586  $ 112,236  The following is a summary of software and other intangible assets: June 30, 2023 December 31, 2022 (thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Customer & supplier relationships $ 62,268  $ 28,655  $ 33,613  $ 62,268  $ 25,762  $ 36,506  Permits 60,690  4,577  56,113  60,690  2,697  57,993  Software 10,090  3,992  6,098  13,643  7,378  6,265  Non-compete agreements 4,413  3,799  614  4,421  3,665  756  Patents, formulae, and licenses 1,769  1,003  766  1,769  971  798  Other* 601  714  (113) 597  580  17  Total software and intangible assets $ 139,831  $ 42,740  $ 97,091  $ 143,388  $ 41,053  $ 102,335  *Other intangibles include an above market lease acquired in September 2021 that had a fair value of ($0.7) million upon acquisition and is being accreted over the remaining useful life of the lease. Amortization expense was $2.9 million for the second quarter ended June 30, 2023, and $1.4 million for the second quarter ended June 18, 2022. Amortization expense was $5.6 million for the first half ended June 30, 2023, and $2.8 million for the first half ended June 18, 2022. The weighted average useful lives of software and other intangibles are as follows: Weighted Average Useful Life (years) Permits 17 Patents, formulae, & licenses 15 Customer and supplier relationships 12 Software 9 Non-compete agreements 5 Other 7     The estimated amortization expense for the remainder of fiscal 2023 and each of the five succeeding fiscal years is as follows: (millions) Fiscal Year Amortization Expense 2023 $4.8 2024 8.5 2025 7.5 2026 7.0 2027 6.9 2028 6.8 The preceding expected amortization expense is an estimate. Actual amounts of amortization expense may differ from estimated amounts due to additional intangible asset acquisitions, the finalization of the fair value of intangible assets that have been acquired from business combinations, disposal of intangible assets, accelerated amortization of intangible assets, and other events.

v3.23.2

ACCOUNTS PAYABLE	6 Months Ended
	Jun. 30, 2023
Payables and Accruals [Abstract]
ACCOUNTS PAYABLE	ACCOUNTS PAYABLE Accounts payable consisted of the following: (thousands) June 30, 2023 December 31, 2022 Accounts payable $ 51,763  $ 54,935  Accounts payable - related parties 839  152  Total accounts payable $ 52,602  $ 55,087

v3.23.2

DEBT AND FINANCING ARRANGEMENTS	6 Months Ended
	Jun. 30, 2023
Debt Disclosure [Abstract]
DEBT AND FINANCING ARRANGEMENTS	DEBT AND FINANCING ARRANGEMENTS Bank Credit Facility On March 18, 2021, Heritage-Crystal Clean, LLC, (the “Company”), entered into an Amended and Restated Credit Agreement (the "Agreement"), by and among the Company, its parent, Heritage-Crystal Clean, Inc., and the Company’s subsidiaries identified therein and Bank of America, N.A., as administrative agent, JPMorgan Chase Bank, N.A., and Wells Fargo Bank, National Association. The new Agreement provides for borrowings of up to $100.0 million, in the form of a revolving facility, of which $15 million can be used in the form of a Swing Line loan. The Agreement also provided for up to an additional $50.0 million of borrowings using an accordion feature upon approval of the lenders. On August 3, 2022, the Company entered into an Amendment (Amendment No. 1 to the Agreement "the Amendment") which increased the amount of borrowing under the revolving credit line to $150.0 million. The Company utilized the credit line to finance $115.0 million of the acquisition of Patriot Environmental Services Inc. (see Note 3). The Amendment also provides for up to an additional $50.0 million of borrowings under an accordion feature upon approval of the lenders. Loans made under the Agreement, as amended, may be Base Rate Loans or Secured Overnight Financing Rate ("SOFR") Loans, at the election of the Borrower subject to certain exceptions. Base Rate Loans have an interest rate equal to (i) the higher of (a) the federal funds rate plus 0.5%, (b) the SOFR plus a margin of 1%, or (c) Bank of America's prime rate, plus a margin of 1.00%. SOFR rate loans have an interest rate equal to (i) the SOFR rate plus (ii) a variable margin of between 1.50% and 2.25% depending on the Company's total leverage ratio. Amounts borrowed under the Agreement are secured by a security interest in substantially all of the Company's tangible and intangible assets. In August 2022, the Company incurred an additional $0.1 million of debt issuance costs related to the amendment of the credit agreement and drawdown. The Company's weighted average interest rate for all debt for the second quarter ended June 30, 2023 was 6.6%. The Credit Agreement contains customary terms and provisions (including representations, covenants, and conditions) for transactions of this type. Certain covenants, among other things, restrict the Company's and its subsidiaries' ability to incur indebtedness, grant liens, make investments and sell assets. The Credit Agreement also contains customary events of default, covenants and representations and warranties. Financial covenants include: •An interest coverage ratio (based on interest expense and EBITDA) of at least 3.5 to 1.0; •A total leverage ratio no greater than 3.0 to 1.0, provided that in the event of a permitted acquisition having an aggregate consideration equal to $10.0 million or more, at the Borrower’s election, the foregoing 3.00 to 1.00 shall be deemed to be 3.50 to 1.00 for the fiscal quarter in which such permitted acquisition occurs and the three immediately following fiscal quarters and will thereafter revert to 3.00 to 1.00. The Credit Agreement places certain limitations on acquisitions and the payment of dividends. Long-term debt at June 30, 2023 and December 31, 2022 consisted of the following: (thousands) June 30, 2023 December 31, 2022 Long-term debt $ 85,000  $ 90,000  Less: unamortized debt issuance costs 521  617  Long-term debt - net $ 84,479  $ 89,383  For the second quarter ended June 30, 2023, the Company recorded interest expense of $1.9 million with respect to our credit line and related amortization of debt issuance costs. For the second quarter ended June 18, 2022, the Company recorded interest expense of $0.3 million with respect to our term loan and credit line, and related amortization of debt issuance costs. For the first half of fiscal 2023, the Company recorded interest expense of $3.7 million with respect to our credit line and related amortization of debt issuance costs. For the first half of fiscal 2022, the Company recorded $0.5 million in amortization of debt issuance costs. As of June 30, 2023 and December 31, 2022, the Company was in compliance with all covenants under its Credit Agreement. As of June 30, 2023 and December 31, 2022, the Company had $6.0 million of standby letters of credit issued for both periods, and $59.0 million and $54.0 million was available for borrowing under the bank credit facility, respectively.

v3.23.2

SEGMENT INFORMATION	6 Months Ended
	Jun. 30, 2023
Segment Reporting [Abstract]
SEGMENT INFORMATION	SEGMENT INFORMATION Effective January 1, 2023, the Company revised its reportable segments as a result of the Patriot Environmental Services, Inc. acquisition. Previously we had two reportable segments: "Environmental Services," and "Oil Business." Under the revised segment presentation, the Company now has three reportable segments: "Environmental Services," "Oil Business," and "Industrial and Field Services." The Environmental Services segment consists primarily of the Company's parts cleaning, containerized waste management, wastewater vacuum services, and antifreeze recycling activities. The Oil Business segment consists primarily of the Company's used oil collection, used oil re-refining activities, and the dehydration of used oil to be sold as recycled fuel oil. The Industrial and Field Services segment consists of the Company's industrial and field services, emergency and spill response services, as well as the activities at our non-hazardous waste processing facilities. Prior period segment results presented for comparative purposes below have been recast to reflect the newly reportable segment as a separate segment. Segment results for the second quarter ended June 30, 2023 and June 18, 2022 were as follows: Second Quarter Ended, June 30, 2023 (91 days) (thousands) Environmental Services Oil Business Industrial and Field Services Corporate and Eliminations Consolidated Revenues Service revenues $ 72,018  $ 2,855  $ 46,469  $ —  $ 121,342  Product revenues 15,875  46,266  —  —  62,141  Rental income 8,072  11  600  —  8,683  Total revenues $ 95,965  $ 49,132  $ 47,069  $ —  $ 192,166  Operating expenses Operating costs 68,459 40,781 37,147 —  146,387  Operating depreciation and amortization 3,641 2,675 2,398 —  8,714  Profit before corporate selling, general, and administrative expenses $ 23,865  $ 5,676  $ 7,524  $ —  $ 37,065  Selling, general, and administrative expenses 20,361 20,361 Depreciation and amortization from SG&A 3,088 3,088 Total selling, general, and administrative expenses $ 23,449  $ 23,449  Other (income) - net (265) (265) Operating income 13,881 Interest expense – net 1,929 1,929 Income before income taxes $ 11,952  Second Quarter Ended, June 18, 2022 (84 days) (thousands) Environmental Services Oil Business Industrial and Field Services Corporate and Eliminations Consolidated Revenues Service revenues $ 59,277  $ 2,604  $ 13,703  $ —  $ 75,584  Product revenues 12,633  62,156  —  —  74,789  Rental income 6,265  9  —  —  6,274  Total revenues $ 78,175  $ 64,769  $ 13,703  $ —  $ 156,647  Operating expenses Operating costs 56,812 35,841 12,102 —  104,755 Operating depreciation and amortization 2,769 2,125 423 —  5,317 Profit before corporate selling, general, and administrative expenses $ 18,594  $ 26,803  $ 1,178  $ —  $ 46,575  Selling, general, and administrative expenses 15,024 15,024 Depreciation and amortization from SG&A 1,460 1,460 Total selling, general, and administrative expenses $ 16,484  $ 16,484  Other expense - net 1,001  1,001 Operating income 29,090 Interest expense – net 250 250 Income before income taxes $ 28,840  First Half Ended, June 30, 2023 (181 days) (thousands) Environmental Services Oil Business Industrial and Field Services Corporate and Eliminations Consolidated Revenues Service revenues $ 143,018  $ 5,665  $ 92,111  $ —  $ 240,794  Product revenues 32,075  96,406  —  —  128,481  Rental income 15,639  17  716  —  16,372  Total revenues $ 190,732  $ 102,088  $ 92,827  $ —  $ 385,647  Operating expenses Operating costs 136,999 77,079 72,370 —  286,448 Operating depreciation and amortization 7,140 5,280 5,476 —  17,896 Profit before corporate selling, general, and administrative expenses $ 46,593  $ 19,729  $ 14,981  $ —  $ 81,303  Selling, general, and administrative expenses 38,061 38,061 Depreciation and amortization from SG&A 6,073 6,073 Total selling, general, and administrative expenses $ 44,134  $ 44,134  Other (income) - net (734) (734) Operating income 37,903 Interest expense – net 3,743 3,743 Income before income taxes $ 34,160  First Half Ended, June 18, 2022 (168 days) (thousands) Environmental Services Oil Business Industrial and Field Services Corporate and Eliminations Consolidated Revenues Service revenues $ 114,479  $ 5,212  $ 24,809  $ —  $ 144,500  Product revenues 25,013  114,249  —  —  139,262  Rental income 12,228  23  —  —  12,251  Total revenues $ 151,720  $ 119,484  $ 24,809  $ —  $ 296,013  Operating expenses Operating costs 114,837 70,006 21,695 —  206,538 Operating depreciation and amortization 5,236 4,209 845 —  10,290 Profit before corporate selling, general, and administrative expenses $ 31,647  $ 45,269  $ 2,269  $ —  $ 79,185  Selling, general, and administrative expenses 28,759 28,759 Depreciation and amortization from SG&A 2,995 2,995 Total selling, general, and administrative expenses $ 31,754  $ 31,754  Other expense - net 791 791 Operating income 46,640 Interest expense – net 473 473 Income before income taxes $ 46,167  Intersegment revenues for the first half of fiscal 2023 and fiscal 2022 in the Industrial & Field services segment were $5.2 million and $3.9 million, respectively. The Environmental Services segment and the Oil Business segment had no intersegment revenues for the second quarter of fiscal 2023 and fiscal 2022. Total assets by segment as of June 30, 2023 and December 31, 2022 were as follows: (thousands) June 30, 2023 December 31, 2022 Total Assets: Environmental Services $ 258,031  $ 253,906  Oil Business 186,153  190,862  Industrial and Field Services 290,210  283,683  Unallocated Corporate Assets 78,397  65,790  Total $ 812,791  $ 794,241  Segment assets for the Environmental Services, Oil Business, and Industrial & Field Services segments consist of property, plant, and equipment, right-of-use assets, intangible assets, accounts receivable, goodwill, and inventories. Assets for the corporate unallocated amounts consist of property, plant, and equipment used at the corporate headquarters as well as cash and net deferred tax assets.

v3.23.2

COMMITMENTS AND CONTINGENCIES	6 Months Ended
	Jun. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES LEASES Lessee The Company leases buildings and property, railcars, machinery and equipment, and various types of vehicles and trailers for use in our operations. Each arrangement is evaluated individually to determine if the arrangement is or contains a lease at inception. The Company has lease agreements with lease and non-lease components and we have elected to not separate lease and non-lease components for all classes of underlying assets. In addition, our lease agreements do not contain any material residual guarantees or restrictive covenants. Leases may include variable lease payments for common area maintenance, real estate taxes, and truck lease mileage. Variable lease payments are not included in the initial measurement of the right-of-use assets or lease liabilities, and are recorded as lease expense in the period incurred. Options to extend or terminate a lease are included in the lease term when it is reasonably certain that we will exercise that option. We have elected not to record leases with an initial term of 12 months or less on the balance sheet and instead recognize those lease payments on a straight-line basis over the lease term. Leases with initial terms in excess of 12 months are recorded as either operating or financing leases in our Consolidated Balance Sheet. Right-of-use assets represent the Company's right to use an underlying asset during the lease term and lease liabilities represent the Company's obligation to make lease payments arising from the lease. Our leased right-of-use assets are measured at the initial measurement of the lease liability, adjusted for any lease payments made prior to the lease commencement date, less any lease incentives received and other initial direct costs incurred. Our lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As most of our leases do not provide an implicit rate, we use an incremental borrowing rate based on the information available at commencement date, including lease term, in determining the present value of future payments. Our leases have remaining terms ranging from less than one month to approximately 11 years and may include options to extend or terminate the lease when it is reasonably certain that the option will be exercised. Lease expense is recognized on a straight-line basis over the lease term. Our finance leases include a fleet of mobile equipment. Lessor The Company is a lessor of portions of buildings and property, and equipment such as embedded leases of parts cleaning machines. Each of the Company’s leases is classified as an operating lease, and the vast majority are short-term leases. Variable lease payments include real and personal property taxes, which are based on the lessee’s pro rata portion of such amounts, and excess mileage charges which are computed as the actual miles traveled in a calendar year minus the maximum average mileage allowance as specified per the contract. Options to extend the lease beyond the original terms range from day-to-day renewals to increments of five-year extensions. Options to terminate the lease range from immediate termination upon return of the asset to various written notification periods following a minimum lease term. Options for a lessee to purchase the underlying asset are not contractually specified but may be negotiated on a case-by-case basis. Significant judgments made in determining whether a contract contains a lease include assessments as to whether or not the contract conveys the right to direct the use of an identified asset. Significant judgments made in allocating consideration between lease and non-lease components include techniques applied in estimating the relative stand-alone selling prices of the lease and non-lease components of the contract in cases where a stand-alone selling price is not directly observable. No leased assets are covered by residual value guarantees. The Company manages the risk associated with the residual value of leased assets through such means as performing periodic maintenance and upkeep activities and the inclusion of contractual terms that hold the lessee responsible for damage incurred to leased assets. The Company has made an accounting policy election to exclude from the consideration in the contract, and from variable payments not included in the consideration in the contract, all taxes assessed by a governmental authority that are both imposed on and concurrent with a specific lease revenue-producing transaction and collected by the lessor from a lessee. The Company recognizes rental income on a straight-line basis for that portion of the consideration allocated to the embedded lease component of certain of our parts cleaning contracts. We also recognize rental income on certain subleases of portions of buildings and property. Rental income was as follows: Second Quarter Ended, June 30, 2023 (91 days) June 18, 2022 (84 days) (thousands) Environmental Services Oil Business Industrial and Field Services Total Environmental Services Oil Business Industrial and Field Services Total Parts Cleaning $ 7,968  $ —  $ 600  $ 8,568  $ 6,233  $ —  $ —  $ 6,233  Property 104  11  —  115  32  9  —  41  Total rental income $ 8,072  $ 11  $ 600  $ 8,683  $ 6,265  $ 9  $ —  $ 6,274  First Half Ended, June 30, 2023 (181 days) June 18, 2022 (168 days) (thousands) Environmental Services Oil Business Industrial and Field Services Total Environmental Services Oil Business Industrial and Field Services Total Parts Cleaning $ 15,518  $ —  $ 716  $ 16,234  $ 12,172  $ —  $ —  $ 12,172  Property 121  17  —  138  56  23  —  79  Total rental income $ 15,639  $ 17  $ 716  $ 16,372  $ 12,228  $ 23  $ —  $ 12,251  Purchase Obligations The Company may enter into purchase obligations with certain vendors. They represent expected payments to third party service providers and other commitments entered into during the normal course of our business. These purchase obligations are generally cancellable with or without notice, without penalty, although certain vendor agreements provide for cancellation fees or penalties depending on the terms of the contract. The Company has purchase obligations in the form of open purchase orders of $21.3 million as of June 30, 2023, and $20.7 million as of December 31, 2022, primarily for used oil, solvent, machine purchases, disposal and transportation expenses, and capital expenditures. Litigation and Claims The Company may be subject to investigations, claims or lawsuits as a result of operating its business, including matters governed by environmental laws and regulations. The Company may also be subject to tax audits in a variety of jurisdictions. When claims are asserted, the Company evaluates the likelihood that a loss will occur and records a liability for those instances when the likelihood is deemed probable and the exposure is reasonably estimable. The Company carries insurance at levels it believes are adequate to cover loss contingencies based on historical claims activity. When the potential loss exposure is limited to the insurance deductible and the likelihood of loss is determined to be probable, the Company accrues for the amount of the required deductible, unless a lower amount of exposure is estimated. As of June 30, 2023 and December 31, 2022, the Company had accrued $3.1 million and $3.2 million related to loss contingencies and other contingent liabilities

v3.23.2

INCOME TAXES	6 Months Ended
	Jun. 30, 2023
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES Income tax expense for the second fiscal quarter of 2023 was $3.3 million. The Company's effective income tax rate for the second quarter of fiscal 2023 was 27.7% compared to 27.0% in the second quarter of fiscal 2022. Tax expense for the first half of 2023 was $8.9 million. The Company’s effective income tax rate for the first half of 2023 was 26.1% compared to 26.4% in the first half of 2022. The rate decrease is principally attributable to the increased impact of certain favorable adjustments to financial reporting income due to decreased levels of profitability as compared to the first half of fiscal 2022. The Company establishes reserves when it is more likely than not that the Company will not realize the full tax benefit of a position. The Company had a reserve of $2.2 million for uncertain tax positions as of June 30, 2023. The gross unrecognized tax benefits would, if recognized, decrease the Company's effective tax rate. As of June 30, 2023, the Company believes it is more likely than not that a benefit from foreign net operating loss carryforwards will not be realized. The Company provided a valuation allowance against those foreign net operating loss carryforwards of $0.7 million.

v3.23.2

SHARE-BASED COMPENSATION	6 Months Ended
	Jun. 30, 2023
Share-Based Payment Arrangement [Abstract]
SHARE-BASED COMPENSATION	SHARE-BASED COMPENSATION  Restricted Stock Compensation/Awards Annually, the Company grants restricted shares to its Board of Directors. The shares become fully vested one year from their grant date. The fair value of each restricted stock grant is based on the closing price of the Company's common stock on the date of grant. The Company amortizes the expense over the service period, which is the fiscal year in which the award is granted. In addition, the Company may grant restricted shares to certain members of management based on their services and contingent upon continued service with the Company. The restricted shares vest over a period of approximately three years from the grant date. The fair value of each restricted stock grant is based on the closing price of the Company's common stock on the date of grant. On November 14, 2022, the Company granted 147,623 shares of restricted stock to certain members of Management as part of a Special Incentive Program. Up to 147,623 shares may vest on September 21, 2025. One-third of the shares vest in equal installments on each the first three anniversaries of September 21, 2022, subject to continuous employment or service with the Company through such date. Two-thirds of the shares are subject to the performance-based vesting terms based on the Company achieving certain Share Price Targets as set forth in the agreement during the three-year period beginning on September 21, 2022 (the “Performance Period”) and the Executive remaining employed by the Company through the Performance Period. The following table shows a summary of restricted share grants and expense resulting from the awards:      Compensation Expense (thousands, except share amounts) First Half Ended, Unrecognized Expense as of, Recipient of Grant Grant Date Restricted Shares June 30, 2023 (181 days) June 18, 2022 (168 days) June 30, 2023 (181 days) June 18, 2022 (168 days) Special Incentive Grant April, 2018 350,000 $ —  $ 380  $ —  $ —  Members of Management February, 2020 41,138 —  40  —  47  Members of Management February, 2021 35,898 104  103  103  345  Chief Executive Officer February, 2021 500,000 502  1,067  1,334  2,814  Members of Management February, 2022 75,355 249 245  735  1,303  Members of Management February, 2023 66,024 310 248  1,552  —  Board of Directors April, 2022 17,082 —  234  —  246  Special Incentive Grant November, 2022 147,623 524 —  2,339  —  Board of Directors May, 2023 14,274 280 —  200  —  At June 30, 2023, there was $6.3 million of unrecognized stock-based compensation expense which is expected to be recognized over a weighted-average remaining vesting period of 1.7 years. On January 8, 2021, the Company and Mr. Brian Recatto entered into an amended Executive Employment Agreement (the “Amended Agreement”) which was effective on February 1, 2021. Pursuant to the Amended Agreement, the Company replaced in its entirety section 4.3 of the First Amendment to the Executive Employment Agreement relating to equity compensation that was effective February 1, 2017. As of February 1, 2021, Mr. Recatto received a one-time award of 500,000 shares of restricted stock, subject to the achievement of performance criteria established by the Compensation Committee of the Board of Directors pursuant to the Company's 2019 Incentive Plan. The award date for such Performance-Based Restricted Stock was on February 1, 2021. Such award was granted pursuant to and governed by the terms of the 2019 Incentive Plan and an award agreement in a form provided by the Company. The Performance-Based Restricted Stock one-time award of 500,000 shares received on February 1, 2021, shall vest on January 31, 2025 if Mr. Recatto is employed by the Company on that date, in an amount determined by applying the applicable percentages from the chart below, with the common stock price increases to be determined based on the increase in the price of the Company’s common stock (if any) from the closing price of the common stock as reported by Nasdaq on the amended agreement commencement date ($21.77) and the common stock price on the potential vesting date (determined by using the average closing price of a share of the Company's common stock for the 90-day period ending on the vesting date). If the stock price does not increase by $5.00, then no shares shall vest. During the second quarter of fiscal 2023, the Company recorded approximately $0.2 million of compensation expense related to this award. In the future, the Company expects to recognize compensation expense of approximately $1.3 million over the remaining requisite service period, which ends January 31, 2025. The fair value of this restricted stock award as of the grant date was estimated using a Monte Carlo simulation model. Key assumptions used in the Monte Carlo simulation to estimate the grant date fair value of this award are a risk-free rate of 0.29%, expected dividend yield of zero, and an expected volatility assumption of 53.07%. Vesting Table Increase in Stock Price From the Amended Agreement Commencement Date to the Vesting Date Total Percentage of Restricted Stock Shares to Be Vested Less than $5 per share increase —% $5 per share increase 25% (vest in 125,000 shares) $10 per share increase 50% (vest in 250,000 shares) $15 per share increase 75% (vest in 375,000 shares) $20 or more per share increase 100% (vest in 500,000 shares) Provision for possible accelerated vesting of award If the average closing price of the Company's common stock increases by the marginal levels set forth in the above vesting table for any consecutive 180 day period between February 1, 2021 and January 31, 2025, Mr. Recatto shall become vested in 50% of the corresponding total percentage of restricted shares earned on the last day of the 180 day period. In addition, on each of December 31, 2021, December 31, 2022, and December 31, 2023, to the extent Mr. Recatto remains employed by the Company under the Amended Agreement on such date, Mr. Recatto shall receive a grant of restricted stock as of such date valued at Five Hundred Thousand Dollars ($500,000), with the number of shares of restricted stock constituting such grant determined by applying the average closing price for a share of the Company’s common stock for the 90-day period ending on such date. Such awards of Time-Based Restricted Stock shall be granted pursuant to and governed by the terms of the 2019 Incentive Plan and an award agreement in a form provided by the Company. The Time-Based Restricted Stock shall vest only if Mr. Recatto remains employed by the Company under the Amended Agreement through December 31, 2023; provided, that, upon a Change of Control of the Company (as such term is defined in the Amended Agreement), all shares of the Time-Based Restricted Stock awarded up through the date of closing of the Change in Control shall become vested, and no further award of Time-Based Restricted Stock shall be awarded. During the second quarter of fiscal 2023, the Company recorded approximately $0.1 million of compensation expense related to this award. The following table summarizes the restricted stock activity for the second quarter ended June 30, 2023: Restricted Stock (Nonvested Shares) Number of Shares Weighted Average Grant-Date Fair Value Per Share Nonvested shares outstanding at December 31, 2022 728,693  $ 21.83  Granted 80,298  37.08  Vested (99,487) 25.51  Forfeited (28,797) 21.95  Nonvested shares outstanding at June 30, 2023 680,707  $ 25.79  Employee Stock Purchase Plan As of June 30, 2023, the Company had reserved 31,438 shares of common stock available for purchase under the Employee Stock Purchase Plan. In the second quarter of fiscal 2023, employees purchased 5,070 shares of the Company’s common stock with a weighted average fair market value of $35.24 per share.

v3.23.2

EARNINGS PER SHARE	6 Months Ended
	Jun. 30, 2023
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHAREThe following table reconciles the number of shares outstanding for the second quarter of fiscal 2023 and 2022, respectively, to the number of weighted average basic shares outstanding and the number of weighted average diluted shares outstanding for the purposes of calculating basic and diluted earnings per share:   Second Quarter Ended, First Half Ended,  (thousands, except per share amounts) June 30, 2023 (91 days) June 18, 2022 (84 days) June 30, 2023 (181 days) June 18, 2022 (168 days) Net income $ 8,642  $ 21,107  $ 25,231  $ 33,985  Weighted average basic shares outstanding 23,681  23,489  23,665  23,482  Dilutive shares for share–based compensation plans 250  155  233  158  Weighted average diluted shares outstanding 23,931  23,644  23,898  23,640  Net income per share: basic $ 0.36  $ 0.90  $ 1.07  $ 1.45  Net income per share: diluted $ 0.36  $ 0.89  $ 1.06  $ 1.44

v3.23.2

FAIR VALUE MEASUREMENTS	6 Months Ended
	Jun. 30, 2023
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Recurring Fair Value Measurements The following tables summarize assets measured at fair value on a recurring basis (in millions) as of June 30, 2023:   Quoted prices in active markets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Fair Value Measurements Equity Securities (1) $— $— $15.2 $15.2 (1) Represents a $3.0 million investment the Company made in its privately held battery recycling partner, HBR Retriev Holdco, LLC, a company controlled by the Heritage Group, an affiliate of the Company.

v3.23.2

SUBSEQUENT EVENTS	6 Months Ended
	Jun. 30, 2023
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS On July 19, 2023, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) with JFL-Tiger Acquisition Co., Inc., a Delaware corporation (“Parent”), and JFL-Tiger Merger Sub, Inc., a Delaware corporation and wholly owned subsidiary of Parent (“Merger Sub”), pursuant to which, upon the terms and subject to the conditions set forth therein, Merger Sub will merge with and into the Company, with the Company surviving the merger as a wholly-owned subsidiary of Parent (the “Merger,” and together with the transactions contemplated by the Merger Agreement, the “Transaction”). Pursuant to the Merger Agreement, at the effective time of the Merger (the “Effective Time”), each share of common stock of the Company then outstanding will be converted into the right to receive $45.50 in cash, without interest (the “Per Share Merger Consideration”), less any applicable withholding taxes, other than any shares as to which dissenters’ rights have been perfected (and not withdrawn or lost) in accordance with applicable law (which will be cancelled and converted into the right to receive a payment determined in accordance with Section 262 of the Delaware General Corporation Law). The Merger Agreement also provides that immediately prior to the Effective Time, by virtue of the Merger and without any action on the part of the holder thereof (1) each outstanding Company restricted stock award will become fully vested and the restrictions with respect thereto will lapse, and all Company restricted stock awards will be treated in the Merger in the same manner as the other shares of Company Common Stock, and (2) each award of Company restricted stock units (“RSU”) that is outstanding immediately prior to the Effective Time will automatically be cancelled and converted into the right to receive a cash payment in an amount, without interest thereon and subject to applicable withholding taxes, equal to the product of (x) the Per Share Merger Consideration and (y) the total number of shares of common stock of the Company subject to such award of RSUs as of immediately prior to the Effective Time. The obligations of the parties to consummate the Merger are subject to the satisfaction or waiver of customary closing conditions set forth in the Merger Agreement, including, among other conditions, (1) the adoption of the Merger Agreement by the affirmative vote of the stockholders of the Company of not less than 75% of the issued and outstanding shares of common stock of the Company (the “Company Stockholder Approval”), (2) the expiration or termination of any waiting period applicable under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and (3) the absence of a “Company Material Adverse Effect” (as defined in the Merger Agreement) with respect to the Company. Each of the Company, Parent and Merger Sub has made customary representations and warranties and covenants in the Merger Agreement, including covenants to use their respective reasonable best efforts to effect the Transaction, including securing regulatory approvals required by the Merger Agreement. In addition, the Company has agreed to other customary covenants, including, among others, covenants to conduct its business in the ordinary course during the interim period between the execution of the Merger Agreement and the closing of the Merger. The Merger Agreement contains customary termination rights for each of Parent and the Company, including, among others, if (1) the Merger has not been consummated by February 29, 2024 (the “End Date”), (2) the requisite Company Stockholder Approval is not obtained, (3) there is any order or applicable law prohibiting or permanently enjoining the Transaction or (4) the other party breaches its covenants or representations and such breach is not cured within a specified period and would result in the failure of a closing condition in favor of the other party. In addition, the Company may terminate the Merger Agreement in order for the board of directors of the Company to cause or permit the Company to enter into an Alternative Acquisition Agreement with respect to a Superior Proposal, and Parent may terminate the Merger Agreement if the board of directors of the Company changes its recommendation in favor of the Transaction. The Merger Agreement further provides that, upon termination of the Merger Agreement under certain specified circumstances, the Company will be required to pay Parent a termination fee of $42,331,515 (except in the case the Merger Agreement is terminated in connection with a Superior Proposal during the Go-Shop Period, and certain other limited circumstances, in which case such termination fee will be $23,584,701), or Parent will be required to pay the Company a termination fee of $72,568,311 (the “Parent Termination Fee”). The Merger is not subject to a financing condition. Parent has obtained (1) equity financing commitments from certain investment affiliates of J.F. Lehman & Company, LLC (“JFLCO”) and certain investment affiliates of HarbourVest Partners, and (2) debt financing commitments from certain third-party lenders, to fund the transactions contemplated by the Merger Agreement. The Merger Agreement requires Parent to use its reasonable best efforts to obtain the financing on the terms and conditions described in the financing commitments. The Company is entitled to specific performance, subject to the terms and conditions of the Merger Agreement and the applicable equity commitments, to force Parent to close the transaction if all closing conditions are met. In addition, an investment affiliate of JFLCO has also provided a limited guarantee in favor of the Company (the “Limited Guarantee”) with respect to certain obligations of Parent and Merger Sub under the Merger Agreement, including a guarantee of payment of the Parent Termination Fee and certain other reimbursement obligations that may be owed by Parent pursuant to the Merger Agreement.

v3.23.2

ORGANIZATION AND NATURE OF OPERATIONS (Policies)	6 Months Ended
	Jun. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Fiscal Period	Beginning with our 2023 fiscal year, we changed our financial reporting cycle to a calendar year-end and end-of-month quarterly reporting cycle. Accordingly, our 2023 fiscal year began on January 1, 2023 (the day after the end of the 2022 fiscal year) and will end on December 31, 2023, and our 2023 quarters include the three month periods ending March 31, June 30, September 30, and December 31. Prior to 2023, our fiscal year was a 52 or 53 week fiscal year that ended on the Saturday nearest to December 31, and our quarterly reporting cycle included twelve week periods for the first, second, and third quarters and a sixteen week period (or in some cases a seventeen week period) for the fourth quarter. We have not restated, and do not plan to restate, historical results. The table below shows the reporting periods as we refer to them in this report, their date ranges, and the number of days in each: Reporting Period Date Range Number of Days 2023 second quarter April 1, 2023 - June 30, 2023 91 2022 second quarter March 27, 2022 - June 18, 2022 84 2023 first half January 1, 2023 - June 30, 2023 181 2022 first half January 2, 2022 - June 18, 2022 168 2023 fiscal year January 1, 2023 - December 31, 2023 365 2022 fiscal year January 2, 2022 - December 31, 2022 364
Revenue	We account for a contract when it has approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance and collectability of consideration is probable. Revenue is recognized when our performance obligations under the terms of a contract with our customers are satisfied. Recognition occurs when the Company transfers control by completing the specified services at the point in time the customer benefits from the services performed or once our products are delivered. The majority of revenue is recognized at a point in time, except for rental income which is recognized on an over time basis. The Company measures progress toward complete satisfaction of a performance obligation satisfied over time using a cost-based input method. This method of measuring progress provides a faithful depiction of the transfer of goods or services because the costs incurred are expected to be substantially proportionate to the Company’s satisfaction of the performance obligation. Revenue is measured as the amount of consideration we expect to receive in exchange for completing our performance obligations. Sales tax and other taxes we collect with revenue-producing activities are excluded from revenue. In the case of contracts with multiple performance obligations, the Company allocates the transaction price to each performance obligation based on the relative stand-alone selling prices of the various goods and/or services encompassed by the contract. We do not have any material significant payment terms as payment is generally due within 30 days after the performance obligation has been satisfactorily completed. The Company has elected the practical expedient to recognize the incremental costs of obtaining a contract as an expense when incurred if the amortization period of the asset that we otherwise would have recognized is one year or less. In applying the guidance in Topic 606, there were no judgments or estimates made that the Company deems significant. Contract Balances — Contract assets primarily relate to the Company’s rights to consideration for work completed in relation to its services performed but not billed at the reporting date. Contract liabilities primarily consist of advance payments of performance obligations yet to be fully satisfied in the period reported. Our contract liabilities and contract assets are reported in a net position at the end of each reporting period. We disaggregate our revenue from contracts with customers by major lines of business for each of our segments, as we believe it best depicts how the nature, amount, timing and uncertainty of our revenue and cash flows are affected by economic factors. As further described in Note 10, prior period segment results presented for comparative purposes below have been recast to reflect the newly reportable segments.
Accounts Receivable	Accounts Receivable — Net, includes amounts billed to and currently due from customers. The amounts due are stated at their net estimated realizable value. The allowance for uncollectible accounts is our best estimate of the amount of probable lifetime-expected credit losses in existing accounts receivable and is determined based on our historical collections experience, age of the receivable, knowledge of the customer and the condition of the general economy and industry as a whole. The Company does not have any off-balance-sheet credit exposure related to its customers.

v3.23.2

ORGANIZATION AND NATURE OF OPERATIONS (Tables)	6 Months Ended
	Jun. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Reporting Periods	The table below shows the reporting periods as we refer to them in this report, their date ranges, and the number of days in each: Reporting Period Date Range Number of Days 2023 second quarter April 1, 2023 - June 30, 2023 91 2022 second quarter March 27, 2022 - June 18, 2022 84 2023 first half January 1, 2023 - June 30, 2023 181 2022 first half January 2, 2022 - June 18, 2022 168 2023 fiscal year January 1, 2023 - December 31, 2023 365 2022 fiscal year January 2, 2022 - December 31, 2022 364

v3.23.2

BUSINESS COMBINATIONS (Tables)	6 Months Ended
	Jun. 30, 2023
Business Combination and Asset Acquisition [Abstract]
Schedule Estimated Fair Values of Assets Acquired, Net of Cash Acquired	The following table summarizes the estimated fair values of the assets acquired, net of cash acquired, related to Patriot at the acquisition date: (thousands) Patriot Environmental Services, Inc.(1) Accounts receivable $ 25,381  Other current assets 2,034  Property, plant, & equipment 33,968  Intangible assets 62,200  Goodwill 62,541  Accounts payable and accruals (12,929) Deferred tax liabilities (16,313) Total purchase price, net of cash acquired $ 156,882  Less: placed in escrow 2,780  Net cash paid $ 154,102  (1) The Company is still in the process of finalizing the purchase price allocation for the acquisition and therefore the following balances are subject to change as a result of any working capital adjustments and seller indemnification obligations: other current assets, goodwill, and accounts payable and accruals.
Schedule of Unaudited Pro Forma Financial Information	The pro forma financial information in the table below presents the combined results of the Company as if the Patriot acquisition had occurred on January 1, 2022. The pro forma information is shown for illustrative purposes only and is not necessarily indicative of future results of operations of the Company or results of operations of the Company that would have actually occurred had the transactions been in effect for the periods presented. Second Quarter Ended, (thousands, except per share data) June 30, 2023 (91 days) June 18, 2022 (84 days) Total revenues $ 192,166  $ 184,361  Net income $ 8,642  $ 21,065  Net income per share: basic $ 0.36  $ 0.90  Net income per share: diluted $ 0.36  $ 0.89  First Half Ended, (thousands, except per share data) June 30, 2023 (181 days) June 18, 2022 (168 days) Total revenues $ 385,647  $ 353,806  Net income $ 25,231  $ 32,652  Net income per share: basic $ 1.07  $ 1.39  Net income per share: diluted $ 1.06  $ 1.38

v3.23.2

REVENUE (Tables)	6 Months Ended
	Jun. 30, 2023
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue by Major Lines	The following table disaggregates our revenue by major lines: Second Quarter Ended, June 30, 2023 (91 days) June 18, 2022 (84 days) Total Net Sales by Major Lines of Business (thousands) Environmental Services Oil Business Industrial and Field Services Total Environmental Services Oil Business Industrial and Field Services Total Parts Cleaning, Containerized Waste, & related products/services $ 57,885  $ —  $ 1,455  $ 59,340  $ 49,217  $ —  $ 1,103  $ 50,320  Vacuum Services & Wastewater Treatment 21,116  —  6,458  27,574  15,089  —  6,061  21,150  Industrial & Field Services —  —  38,556  38,556  —  —  6,539  6,539  Antifreeze Business 8,439  —  —  8,439  7,118  —  —  7,118  Environmental Services - Other 453  —  —  453  486  —  —  486  Re-refinery Product Sales —  41,820  —  41,820  —  54,198  —  54,198  Oil Collection Services & RFO —  6,002  —  6,002  —  9,253  —  9,253  Oil Filter Business —  1,299  —  1,299  —  1,309  —  1,309  Revenues from Contracts with Customers 87,893  49,121  46,469  183,483  71,910  64,760  13,703  150,373  Rental Income 8,072  11  600  8,683  6,265  9  —  6,274  Total Revenues $ 95,965  $ 49,132  $ 47,069  $ 192,166  $ 78,175  $ 64,769  $ 13,703  $ 156,647  First Half Ended, June 30, 2023 (181 days) June 18, 2022 (168 days) Total Net Sales by Major Lines of Business (thousands) Environmental Services Oil Business Industrial and Field Services Total Environmental Services Oil Business Industrial and Field Services Total Parts cleaning, containerized waste, & related products/services $ 114,543  $ —  $ 2,924  $ 117,467  $ 95,340  $ —  $ 1,836  $ 97,176  Wastewater Vacuum Services 41,460  —  12,883  54,343  28,397  —  10,144  38,541  Field Services —  —  76,304  76,304  —  —  12,829  12,829  Antifreeze Business 18,115  —  —  18,115  14,774  —  —  14,774  Environmental Services - Other 975  —  —  975  981  —  —  981  Re-refinery Product Sales —  88,629  —  88,629  —  103,337  —  103,337  Oil Collection Services & RFO —  10,740  —  10,740  —  13,566  —  13,566  Oil Filter Business —  2,702  —  2,702  —  2,558  —  2,558  Revenues from Contracts with Customers 175,093  102,071  92,111  369,275  139,492  119,461  24,809  283,762  Rental income 15,639  17  716  16,372  12,228  23  —  12,251  Total Revenues $ 190,732  $ 102,088  $ 92,827  $ 385,647  $ 151,720  $ 119,484  $ 24,809  $ 296,013
Schedule of Contract Assets and Contract Liabilities	The following table provides information about contract assets and contract liabilities from contracts with customers: (thousands) June 30, 2023 December 31, 2022 Contract assets $ —  $ 133  Contract liabilities 3,259  2,658  Contract liabilities - net $ 3,259  $ 2,525

v3.23.2

ACCOUNTS RECEIVABLE (Tables)	6 Months Ended
	Jun. 30, 2023
Accounts Receivable, after Allowance for Credit Loss [Abstract]
Schedule of Accounts Receivable	Accounts receivable for the second quarter ended June 30, 2023, and the fiscal year ended December 31, 2022 consisted of the following: (thousands) June 30, 2023 December 31, 2022 Trade $ 105,263  $ 111,118  Less: allowance for uncollectible accounts 5,527  4,496  Trade - net 99,736  106,622  Related parties 4,437  6,777  Other 531  1,009  Total accounts receivable - net $ 104,704  $ 114,408  The following table provides the changes in the Company’s allowance for uncollectible accounts for the first half ended June 30, 2023, and the fiscal year ended December 31, 2022: (thousands) June 30, 2023 December 31, 2022 Balance at beginning of period $ 4,496  $ 2,928  Provision for uncollectible accounts 1,270  2,269  Accounts written off, net of recoveries (239) (701) Balance at end of period $ 5,527  $ 4,496

v3.23.2

INVENTORY (Tables)	6 Months Ended
	Jun. 30, 2023
Inventory Disclosure [Abstract]
Schedule of Inventory	The carrying value of inventory consisted of the following:  (thousands) June 30, 2023 December 31, 2022 Solvents and solutions $ 11,829  $ 10,792  Used oil and processed oil 18,991  14,904  Machines 7,206  6,329  Drums and supplies 6,543  6,476  Other 2,910  2,666  Total inventory 47,479  41,167  Less: machine refurbishing reserve 455  440  Total inventory - net $ 47,024  $ 40,727

v3.23.2

GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)	6 Months Ended
	Jun. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following table shows changes to our goodwill balances by segment from December 31, 2022 to June 30, 2023: (thousands) Environmental Services Industrial and Field Services Total Goodwill at December 31, 2022     Gross carrying amount $ 37,650  $ 74,586  $ 112,236  Net book value at December 31, 2022 $ 37,650  $ 74,586  $ 112,236  Goodwill at June 30, 2023      Gross carrying amount 37,650  74,586  $ 112,236  Net book value at June 30, 2023 $ 37,650  $ 74,586  $ 112,236
Schedule of Finite-Lived Intangible Assets	The following is a summary of software and other intangible assets: June 30, 2023 December 31, 2022 (thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Customer & supplier relationships $ 62,268  $ 28,655  $ 33,613  $ 62,268  $ 25,762  $ 36,506  Permits 60,690  4,577  56,113  60,690  2,697  57,993  Software 10,090  3,992  6,098  13,643  7,378  6,265  Non-compete agreements 4,413  3,799  614  4,421  3,665  756  Patents, formulae, and licenses 1,769  1,003  766  1,769  971  798  Other* 601  714  (113) 597  580  17  Total software and intangible assets $ 139,831  $ 42,740  $ 97,091  $ 143,388  $ 41,053  $ 102,335  *Other intangibles include an above market lease acquired in September 2021 that had a fair value of ($0.7) million upon acquisition and is being accreted over the remaining useful life of the lease. The weighted average useful lives of software and other intangibles are as follows: Weighted Average Useful Life (years) Permits 17 Patents, formulae, & licenses 15 Customer and supplier relationships 12 Software 9 Non-compete agreements 5 Other 7
Schedule of Finite-lived Intangible Assets Amortization Expense	The estimated amortization expense for the remainder of fiscal 2023 and each of the five succeeding fiscal years is as follows: (millions) Fiscal Year Amortization Expense 2023 $4.8 2024 8.5 2025 7.5 2026 7.0 2027 6.9 2028 6.8

v3.23.2

ACCOUNTS PAYABLE (Tables)	6 Months Ended
	Jun. 30, 2023
Payables and Accruals [Abstract]
Schedule of Accounts Payable	Accounts payable consisted of the following: (thousands) June 30, 2023 December 31, 2022 Accounts payable $ 51,763  $ 54,935  Accounts payable - related parties 839  152  Total accounts payable $ 52,602  $ 55,087

v3.23.2

DEBT AND FINANCING ARRANGEMENTS (Tables)	6 Months Ended
	Jun. 30, 2023
Debt Disclosure [Abstract]
Schedule of Long-term Debt	Long-term debt at June 30, 2023 and December 31, 2022 consisted of the following: (thousands) June 30, 2023 December 31, 2022 Long-term debt $ 85,000  $ 90,000  Less: unamortized debt issuance costs 521  617  Long-term debt - net $ 84,479  $ 89,383

v3.23.2

SEGMENT INFORMATION (Tables)	6 Months Ended
	Jun. 30, 2023
Segment Reporting [Abstract]
Schedule of Reconciliation of Segment Results to Consolidated	Segment results for the second quarter ended June 30, 2023 and June 18, 2022 were as follows: Second Quarter Ended, June 30, 2023 (91 days) (thousands) Environmental Services Oil Business Industrial and Field Services Corporate and Eliminations Consolidated Revenues Service revenues $ 72,018  $ 2,855  $ 46,469  $ —  $ 121,342  Product revenues 15,875  46,266  —  —  62,141  Rental income 8,072  11  600  —  8,683  Total revenues $ 95,965  $ 49,132  $ 47,069  $ —  $ 192,166  Operating expenses Operating costs 68,459 40,781 37,147 —  146,387  Operating depreciation and amortization 3,641 2,675 2,398 —  8,714  Profit before corporate selling, general, and administrative expenses $ 23,865  $ 5,676  $ 7,524  $ —  $ 37,065  Selling, general, and administrative expenses 20,361 20,361 Depreciation and amortization from SG&A 3,088 3,088 Total selling, general, and administrative expenses $ 23,449  $ 23,449  Other (income) - net (265) (265) Operating income 13,881 Interest expense – net 1,929 1,929 Income before income taxes $ 11,952  Second Quarter Ended, June 18, 2022 (84 days) (thousands) Environmental Services Oil Business Industrial and Field Services Corporate and Eliminations Consolidated Revenues Service revenues $ 59,277  $ 2,604  $ 13,703  $ —  $ 75,584  Product revenues 12,633  62,156  —  —  74,789  Rental income 6,265  9  —  —  6,274  Total revenues $ 78,175  $ 64,769  $ 13,703  $ —  $ 156,647  Operating expenses Operating costs 56,812 35,841 12,102 —  104,755 Operating depreciation and amortization 2,769 2,125 423 —  5,317 Profit before corporate selling, general, and administrative expenses $ 18,594  $ 26,803  $ 1,178  $ —  $ 46,575  Selling, general, and administrative expenses 15,024 15,024 Depreciation and amortization from SG&A 1,460 1,460 Total selling, general, and administrative expenses $ 16,484  $ 16,484  Other expense - net 1,001  1,001 Operating income 29,090 Interest expense – net 250 250 Income before income taxes $ 28,840  First Half Ended, June 30, 2023 (181 days) (thousands) Environmental Services Oil Business Industrial and Field Services Corporate and Eliminations Consolidated Revenues Service revenues $ 143,018  $ 5,665  $ 92,111  $ —  $ 240,794  Product revenues 32,075  96,406  —  —  128,481  Rental income 15,639  17  716  —  16,372  Total revenues $ 190,732  $ 102,088  $ 92,827  $ —  $ 385,647  Operating expenses Operating costs 136,999 77,079 72,370 —  286,448 Operating depreciation and amortization 7,140 5,280 5,476 —  17,896 Profit before corporate selling, general, and administrative expenses $ 46,593  $ 19,729  $ 14,981  $ —  $ 81,303  Selling, general, and administrative expenses 38,061 38,061 Depreciation and amortization from SG&A 6,073 6,073 Total selling, general, and administrative expenses $ 44,134  $ 44,134  Other (income) - net (734) (734) Operating income 37,903 Interest expense – net 3,743 3,743 Income before income taxes $ 34,160  First Half Ended, June 18, 2022 (168 days) (thousands) Environmental Services Oil Business Industrial and Field Services Corporate and Eliminations Consolidated Revenues Service revenues $ 114,479  $ 5,212  $ 24,809  $ —  $ 144,500  Product revenues 25,013  114,249  —  —  139,262  Rental income 12,228  23  —  —  12,251  Total revenues $ 151,720  $ 119,484  $ 24,809  $ —  $ 296,013  Operating expenses Operating costs 114,837 70,006 21,695 —  206,538 Operating depreciation and amortization 5,236 4,209 845 —  10,290 Profit before corporate selling, general, and administrative expenses $ 31,647  $ 45,269  $ 2,269  $ —  $ 79,185  Selling, general, and administrative expenses 28,759 28,759 Depreciation and amortization from SG&A 2,995 2,995 Total selling, general, and administrative expenses $ 31,754  $ 31,754  Other expense - net 791 791 Operating income 46,640 Interest expense – net 473 473 Income before income taxes $ 46,167
Schedule of Reconciliation of Assets by Segment to Consolidated	Total assets by segment as of June 30, 2023 and December 31, 2022 were as follows: (thousands) June 30, 2023 December 31, 2022 Total Assets: Environmental Services $ 258,031  $ 253,906  Oil Business 186,153  190,862  Industrial and Field Services 290,210  283,683  Unallocated Corporate Assets 78,397  65,790  Total $ 812,791  $ 794,241

v3.23.2

COMMITMENTS AND CONTINGENCIES (Tables)	6 Months Ended
	Jun. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Schedule of Rental Income	Rental income was as follows: Second Quarter Ended, June 30, 2023 (91 days) June 18, 2022 (84 days) (thousands) Environmental Services Oil Business Industrial and Field Services Total Environmental Services Oil Business Industrial and Field Services Total Parts Cleaning $ 7,968  $ —  $ 600  $ 8,568  $ 6,233  $ —  $ —  $ 6,233  Property 104  11  —  115  32  9  —  41  Total rental income $ 8,072  $ 11  $ 600  $ 8,683  $ 6,265  $ 9  $ —  $ 6,274  First Half Ended, June 30, 2023 (181 days) June 18, 2022 (168 days) (thousands) Environmental Services Oil Business Industrial and Field Services Total Environmental Services Oil Business Industrial and Field Services Total Parts Cleaning $ 15,518  $ —  $ 716  $ 16,234  $ 12,172  $ —  $ —  $ 12,172  Property 121  17  —  138  56  23  —  79  Total rental income $ 15,639  $ 17  $ 716  $ 16,372  $ 12,228  $ 23  $ —  $ 12,251

v3.23.2

SHARE-BASED COMPENSATION (Tables)	6 Months Ended
	Jun. 30, 2023
Share-Based Payment Arrangement [Abstract]
Schedule of Restricted Stock Unit Activity	The following table shows a summary of restricted share grants and expense resulting from the awards:      Compensation Expense (thousands, except share amounts) First Half Ended, Unrecognized Expense as of, Recipient of Grant Grant Date Restricted Shares June 30, 2023 (181 days) June 18, 2022 (168 days) June 30, 2023 (181 days) June 18, 2022 (168 days) Special Incentive Grant April, 2018 350,000 $ —  $ 380  $ —  $ —  Members of Management February, 2020 41,138 —  40  —  47  Members of Management February, 2021 35,898 104  103  103  345  Chief Executive Officer February, 2021 500,000 502  1,067  1,334  2,814  Members of Management February, 2022 75,355 249 245  735  1,303  Members of Management February, 2023 66,024 310 248  1,552  —  Board of Directors April, 2022 17,082 —  234  —  246  Special Incentive Grant November, 2022 147,623 524 —  2,339  —  Board of Directors May, 2023 14,274 280 —  200  —  The following table summarizes the restricted stock activity for the second quarter ended June 30, 2023: Restricted Stock (Nonvested Shares) Number of Shares Weighted Average Grant-Date Fair Value Per Share Nonvested shares outstanding at December 31, 2022 728,693  $ 21.83  Granted 80,298  37.08  Vested (99,487) 25.51  Forfeited (28,797) 21.95  Nonvested shares outstanding at June 30, 2023 680,707  $ 25.79
Schedule of Restricted Stock Vesting Percentages	Vesting Table Increase in Stock Price From the Amended Agreement Commencement Date to the Vesting Date Total Percentage of Restricted Stock Shares to Be Vested Less than $5 per share increase —% $5 per share increase 25% (vest in 125,000 shares) $10 per share increase 50% (vest in 250,000 shares) $15 per share increase 75% (vest in 375,000 shares) $20 or more per share increase 100% (vest in 500,000 shares)

v3.23.2

EARNINGS PER SHARE (Tables)	6 Months Ended
	Jun. 30, 2023
Earnings Per Share [Abstract]
Schedule of Weighted Average Basic and Diluted Shares Outstanding	The following table reconciles the number of shares outstanding for the second quarter of fiscal 2023 and 2022, respectively, to the number of weighted average basic shares outstanding and the number of weighted average diluted shares outstanding for the purposes of calculating basic and diluted earnings per share:   Second Quarter Ended, First Half Ended,  (thousands, except per share amounts) June 30, 2023 (91 days) June 18, 2022 (84 days) June 30, 2023 (181 days) June 18, 2022 (168 days) Net income $ 8,642  $ 21,107  $ 25,231  $ 33,985  Weighted average basic shares outstanding 23,681  23,489  23,665  23,482  Dilutive shares for share–based compensation plans 250  155  233  158  Weighted average diluted shares outstanding 23,931  23,644  23,898  23,640  Net income per share: basic $ 0.36  $ 0.90  $ 1.07  $ 1.45  Net income per share: diluted $ 0.36  $ 0.89  $ 1.06  $ 1.44

v3.23.2

FAIR VALUE MEASUREMENTS (Tables)	6 Months Ended
	Jun. 30, 2023
Fair Value Disclosures [Abstract]
Schedule of Assets Measured at Fair Value on Recurring Basis	The following tables summarize assets measured at fair value on a recurring basis (in millions) as of June 30, 2023:   Quoted prices in active markets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Fair Value Measurements Equity Securities (1) $— $— $15.2 $15.2 (1) Represents a $3.0 million investment the Company made in its privately held battery recycling partner, HBR Retriev Holdco, LLC, a company controlled by the Heritage Group, an affiliate of the Company.

v3.23.2

ORGANIZATION AND NATURE OF OPERATIONS - Narrative (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2023 facility segment	Dec. 31, 2022 segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of non-hazardous waste processing facilities	12
Number of antifreeze recycling facilities	5
Number of reportable segments | segment	3	2

v3.23.2

BUSINESS COMBINATIONS - Narrative (Details) - Patriot $ in Millions	Aug. 03, 2022 USD ($)
Business Acquisition [Line Items]
Consideration transferred	$ 156.9
Transaction costs	$ 1.2

v3.23.2

BUSINESS COMBINATIONS - Estimated Fair Value of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Aug. 03, 2022	Jun. 30, 2023	Dec. 31, 2022
Business Acquisition [Line Items]
Goodwill		$ 112,236	$ 112,236
Patriot Environmental Services, Inc.
Business Acquisition [Line Items]
Accounts receivable	$ 25,381
Other current assets	2,034
Property, plant, & equipment	33,968
Intangible assets	62,200
Goodwill	62,541
Accounts payable and accruals	(12,929)
Deferred tax liabilities	(16,313)
Total purchase price, net of cash acquired	156,882
Less: placed in escrow	2,780
Net cash paid	$ 154,102

v3.23.2

BUSINESS COMBINATIONS - Schedule of Unaudited Pro Forma Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 18, 2022	Jun. 30, 2023	Jun. 18, 2022
Business Combination and Asset Acquisition [Abstract]
Total revenues	$ 192,166	$ 184,361	$ 385,647	$ 353,806
Net income	$ 8,642	$ 21,065	$ 25,231	$ 32,652
Net (loss) income per share: basic (in dollars per share)	$ 0.36	$ 0.90	$ 1.07	$ 1.39
Net (loss) income per share: diluted (in dollars per share)	$ 0.36	$ 0.89	$ 1.06	$ 1.38

v3.23.2

REVENUE - Schedule of Disaggregation of Revenue by Major Lines (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 18, 2022	Jun. 30, 2023	Jun. 18, 2022
Revenue from Contract with Customer [Abstract]
Performance obligation timing			We do not have any material significant payment terms as payment is generally due within 30 days after the performance obligation has been satisfactorily completed. The Company has elected the practical expedient to recognize the incremental costs of obtaining a contract as an expense when incurred if the amortization period of the asset that we otherwise would have recognized is one year or less. In applying the guidance in Topic 606, there were no judgments or estimates made that the Company deems significant.
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	$ 183,483	$ 150,373	$ 369,275	$ 283,762
Rental Income	8,683	6,274	16,372	12,251
Total revenues	192,166	156,647	385,647	296,013
Environmental Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	87,893	71,910	175,093	139,492
Rental Income	8,072	6,265	15,639	12,228
Total revenues	95,965	78,175	190,732	151,720
Oil Business
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	49,121	64,760	102,071	119,461
Rental Income	11	9	17	23
Total revenues	49,132	64,769	102,088	119,484
Industrial and Field Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	46,469	13,703	92,111	24,809
Rental Income	600	0	716	0
Total revenues	47,069	13,703	92,827	24,809
Parts Cleaning, Containerized Waste, & related products/services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	59,340	50,320	117,467	97,176
Parts Cleaning, Containerized Waste, & related products/services | Environmental Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	57,885	49,217	114,543	95,340
Parts Cleaning, Containerized Waste, & related products/services | Oil Business
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Parts Cleaning, Containerized Waste, & related products/services | Industrial and Field Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,455	1,103	2,924	1,836
Vacuum Services & Wastewater Treatment
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	27,574	21,150
Vacuum Services & Wastewater Treatment | Environmental Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	21,116	15,089
Vacuum Services & Wastewater Treatment | Oil Business
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0
Vacuum Services & Wastewater Treatment | Industrial and Field Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	6,458	6,061
Industrial & Field Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	38,556	6,539
Industrial & Field Services | Environmental Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0
Industrial & Field Services | Oil Business
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0
Industrial & Field Services | Industrial and Field Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	38,556	6,539
Wastewater Vacuum Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers			54,343	38,541
Wastewater Vacuum Services | Environmental Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers			41,460	28,397
Wastewater Vacuum Services | Oil Business
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers			0	0
Wastewater Vacuum Services | Industrial and Field Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers			12,883	10,144
Field Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers			76,304	12,829
Field Services | Environmental Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers			0	0
Field Services | Oil Business
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers			0	0
Field Services | Industrial and Field Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers			76,304	12,829
Antifreeze Business
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	8,439	7,118	18,115	14,774
Antifreeze Business | Environmental Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	8,439	7,118	18,115	14,774
Antifreeze Business | Oil Business
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Antifreeze Business | Industrial and Field Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Environmental Services - Other
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	453	486	975	981
Environmental Services - Other | Environmental Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	453	486	975	981
Environmental Services - Other | Oil Business
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Environmental Services - Other | Industrial and Field Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Re-refinery Product Sales
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	41,820	54,198	88,629	103,337
Re-refinery Product Sales | Environmental Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Re-refinery Product Sales | Oil Business
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	41,820	54,198	88,629	103,337
Re-refinery Product Sales | Industrial and Field Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Oil Collection Services & RFO
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	6,002	9,253	10,740	13,566
Oil Collection Services & RFO | Environmental Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Oil Collection Services & RFO | Oil Business
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	6,002	9,253	10,740	13,566
Oil Collection Services & RFO | Industrial and Field Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Oil Filter Business
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,299	1,309	2,702	2,558
Oil Filter Business | Environmental Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Oil Filter Business | Oil Business
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,299	1,309	2,702	2,558
Oil Filter Business | Industrial and Field Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	$ 0	$ 0	$ 0	$ 0

v3.23.2

REVENUE - Contract Assets and Contract Liabilities from Contracts with Customers (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
Contract assets	$ 0	$ 0	$ 133,000
Contract liabilities	3,259,000	3,259,000	2,658,000
Contract liabilities - net	3,259,000	3,259,000	$ 2,525,000
Revenue recognized	$ 0	$ 2,500,000

v3.23.2

ACCOUNTS RECEIVABLE - Summary of Accounts Receivable (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022	Jan. 01, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade	$ 105,263	$ 111,118
Less: allowance for uncollectible accounts	5,527	4,496	$ 2,928
Trade - net	99,736	106,622
Accounts receivable - net	104,704	114,408
Other	531	1,009
Total accounts receivable - net	104,704	114,408
Related parties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable - net	4,437	6,777
Total accounts receivable - net	$ 4,437	$ 6,777

v3.23.2

ACCOUNTS RECEIVABLE - Rollforward of Allowance (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 18, 2022	Dec. 31, 2022
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 4,496	$ 2,928	$ 2,928
Provision for uncollectible accounts	1,270	$ 453	2,269
Accounts written off, net of recoveries	(239)		(701)
Balance at end of period	$ 5,527		$ 4,496

v3.23.2

INVENTORY - Carrying Value of Inventory (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 18, 2022	Jun. 30, 2023	Jun. 18, 2022	Dec. 31, 2022
Inventory Disclosure [Abstract]
Solvents and solutions	$ 11,829,000		$ 11,829,000		$ 10,792,000
Used oil and processed oil	18,991,000		18,991,000		14,904,000
Machines	7,206,000		7,206,000		6,329,000
Drums and supplies	6,543,000		6,543,000		6,476,000
Other	2,910,000		2,910,000		2,666,000
Total inventory	47,479,000		47,479,000		41,167,000
Less: machine refurbishing reserve	455,000		455,000		440,000
Total inventory - net	47,024,000		47,024,000		$ 40,727,000
Inventory write downs	$ 0	$ 0	$ 0	$ 0

v3.23.2

GOODWILL AND OTHER INTANGIBLE ASSETS - Goodwill Balances (Details) $ in Thousands	Jun. 30, 2023 USD ($)
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	$ 112,236
Net book value, beginning balance	112,236
Goodwill, gross, ending balance	112,236
Net book value, ending balance	112,236
Environmental Services
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	37,650
Net book value, beginning balance	37,650
Goodwill, gross, ending balance	37,650
Net book value, ending balance	37,650
Industrial and Field Services
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	74,586
Net book value, beginning balance	74,586
Goodwill, gross, ending balance	74,586
Net book value, ending balance	$ 74,586

v3.23.2

GOODWILL AND OTHER INTANGIBLE ASSETS - Software and Other Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2021
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 139,831	$ 143,388
Accumulated Amortization	42,740	41,053
Net Carrying Amount	97,091	102,335
Customer & supplier relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	62,268	62,268
Accumulated Amortization	28,655	25,762
Net Carrying Amount	$ 33,613	36,506
Weighted Average Useful Life (years)	12 years
Permits
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 60,690	60,690
Accumulated Amortization	4,577	2,697
Net Carrying Amount	$ 56,113	57,993
Weighted Average Useful Life (years)	17 years
Software
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 10,090	13,643
Accumulated Amortization	3,992	7,378
Net Carrying Amount	$ 6,098	6,265
Weighted Average Useful Life (years)	9 years
Non-compete agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 4,413	4,421
Accumulated Amortization	3,799	3,665
Net Carrying Amount	$ 614	756
Weighted Average Useful Life (years)	5 years
Patents, formulae, and licenses
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,769	1,769
Accumulated Amortization	1,003	971
Net Carrying Amount	$ 766	798
Weighted Average Useful Life (years)	15 years
Other
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 601	597	$ (700)
Accumulated Amortization	714	580
Net Carrying Amount	$ (113)	$ 17
Weighted Average Useful Life (years)	7 years

v3.23.2

GOODWILL AND OTHER INTANGIBLE ASSETS - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 18, 2022	Jun. 30, 2023	Jun. 18, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of intangible assets	$ 2.9	$ 1.4	$ 5.6	$ 2.8

v3.23.2

GOODWILL AND OTHER INTANGIBLE ASSETS - Schedule of Expected Amortization Expense (Details) $ in Millions	Jun. 30, 2023 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2023	$ 4.8
2024	8.5
2025	7.5
2026	7.0
2027	6.9
2028	$ 6.8

v3.23.2

ACCOUNTS PAYABLE (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Accounts payable	$ 52,602	$ 55,087
Accounts payable
Related Party Transaction [Line Items]
Accounts payable	51,763	54,935
Related parties
Related Party Transaction [Line Items]
Accounts payable	$ 839	$ 152

v3.23.2

DEBT AND FINANCING ARRANGEMENTS - Narrative (Details) - USD ($)		3 Months Ended		6 Months Ended
	Aug. 03, 2022	Jun. 30, 2023	Jun. 18, 2022	Jun. 30, 2023	Jun. 18, 2022	Dec. 31, 2022	Mar. 18, 2021
Debt Instrument [Line Items]
Weighted average interest rate		6.60%		6.60%
Interest costs incurred		$ 1,900,000	$ 300,000	$ 3,700,000	$ 500,000
Letters of credit outstanding		6,000,000		6,000,000		$ 6,000,000
Current borrowing capacity		$ 59,000,000		$ 59,000,000		$ 54,000,000
Agreement
Debt Instrument [Line Items]
Debt issuance costs	$ 100,000
Minimum interest coverage ratio	3.5
Maximum total leverage ratio	3.00
Aggregate consideration limit	$ 10,000,000
Leverage ratio at time of acquisition	3.50
Agreement | Revolving Loan Portion
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 150,000,000						$ 100,000,000
Additional borrowings (up to)	50,000,000						50,000,000
Credit line utilized	$ 115,000,000
Agreement | Revolving Loan Portion | Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
Agreement | Revolving Loan Portion | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
Agreement | Revolving Loan Portion | Secured Overnight Financing Rate (SOFR) | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	1.50%
Agreement | Revolving Loan Portion | Secured Overnight Financing Rate (SOFR) | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	2.25%
Agreement | Revolving Loan Portion | Bank of America's Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
Agreement | Swing Line loan
Debt Instrument [Line Items]
Maximum borrowing capacity							$ 15,000,000

v3.23.2

DEBT AND FINANCING ARRANGEMENTS - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Debt Disclosure [Abstract]
Long-term debt	$ 85,000	$ 90,000
Less: unamortized debt issuance costs	521	617
Long-term debt - net	$ 84,479	$ 89,383

v3.23.2

SEGMENT INFORMATION - Operating Segment Results (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 18, 2022 USD ($)	Jun. 30, 2023 USD ($) segment	Jun. 18, 2022 USD ($)	Dec. 31, 2022 segment
Segment Reporting [Abstract]
Number of reportable segments | segment			3		2
Revenues
Revenues	$ 183,483	$ 150,373	$ 369,275	$ 283,762
Rental income	8,683	6,274	16,372	12,251
Total revenues	192,166	156,647	385,647	296,013
Operating expenses
Operating costs	146,387	104,755	286,448	206,538
Operating depreciation and amortization	8,714	5,317	17,896	10,290
Profit before corporate selling, general, and administrative expenses	37,065	46,575	81,303	79,185
Selling, general, and administrative expenses	20,361	15,024	38,061	28,759
Depreciation and amortization from SG&A	3,088	1,460	6,073	2,995
Total selling, general, and administrative expenses	23,449	16,484	44,134	31,754
Other (income) - net	(265)	1,001	(734)	791
Operating income	13,881	29,090	37,903	46,640
Interest expense – net	1,929	250	3,743	473
Income before income taxes	11,952	28,840	34,160	46,167
Environmental Services
Revenues
Revenues	87,893	71,910	175,093	139,492
Rental income	8,072	6,265	15,639	12,228
Total revenues	95,965	78,175	190,732	151,720
Oil Business
Revenues
Revenues	49,121	64,760	102,071	119,461
Rental income	11	9	17	23
Total revenues	49,132	64,769	102,088	119,484
Industrial and Field Services
Revenues
Revenues	46,469	13,703	92,111	24,809
Rental income	600	0	716	0
Total revenues	47,069	13,703	92,827	24,809
Service revenues
Revenues
Revenues	121,342	75,584	240,794	144,500
Product revenues
Revenues
Revenues	62,141	74,789	128,481	139,262
Segments | Environmental Services
Revenues
Rental income	8,072	6,265	15,639	12,228
Total revenues	95,965	78,175	190,732	151,720
Operating expenses
Operating costs	68,459	56,812	136,999	114,837
Operating depreciation and amortization	3,641	2,769	7,140	5,236
Profit before corporate selling, general, and administrative expenses	23,865	18,594	46,593	31,647
Segments | Oil Business
Revenues
Rental income		9	17	23
Total revenues	49,132	64,769	102,088	119,484
Operating expenses
Operating costs	40,781	35,841	77,079	70,006
Operating depreciation and amortization	2,675	2,125	5,280	4,209
Profit before corporate selling, general, and administrative expenses	5,676	26,803	19,729	45,269
Segments | Industrial and Field Services
Revenues
Rental income	600	0	716	0
Total revenues	47,069	13,703	92,827	24,809
Operating expenses
Operating costs	37,147	12,102	72,370	21,695
Operating depreciation and amortization	2,398	423	5,476	845
Profit before corporate selling, general, and administrative expenses	7,524	1,178	14,981	2,269
Segments | Service revenues | Environmental Services
Revenues
Revenues	72,018	59,277	143,018	114,479
Segments | Service revenues | Oil Business
Revenues
Revenues	2,855	2,604	5,665	5,212
Segments | Service revenues | Industrial and Field Services
Revenues
Revenues	46,469	13,703	92,111	24,809
Segments | Product revenues | Environmental Services
Revenues
Revenues	15,875	12,633	32,075	25,013
Segments | Product revenues | Oil Business
Revenues
Revenues	46,266	62,156	96,406	114,249
Segments | Product revenues | Industrial and Field Services
Revenues
Revenues	0	0	0	0
Corporate and Eliminations
Revenues
Rental income	0	0	0	0
Total revenues	0	0	0	0
Operating expenses
Operating costs	0	0	0	0
Operating depreciation and amortization	0	0	0	0
Profit before corporate selling, general, and administrative expenses	0	0	0	0
Selling, general, and administrative expenses	20,361	15,024	38,061	28,759
Depreciation and amortization from SG&A	3,088	1,460	6,073	2,995
Total selling, general, and administrative expenses	23,449	16,484	44,134	31,754
Other (income) - net	(265)	1,001	(734)	791
Interest expense – net	1,929	250	3,743	473
Corporate and Eliminations | Service revenues
Revenues
Revenues	0	0	0	0
Corporate and Eliminations | Product revenues
Revenues
Revenues	$ 0	$ 0	0	0
Intersegment revenue
Revenues
Total revenues			$ 5,200	$ 3,900

v3.23.2

SEGMENT INFORMATION - Assets by Segment (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Assets	$ 812,791	$ 794,241
Segments | Environmental Services
Segment Reporting Information [Line Items]
Assets	258,031	253,906
Segments | Oil Business
Segment Reporting Information [Line Items]
Assets	186,153	190,862
Segments | Industrial and Field Services
Segment Reporting Information [Line Items]
Assets	290,210	283,683
Unallocated Corporate Assets
Segment Reporting Information [Line Items]
Assets	$ 78,397	$ 65,790

v3.23.2

COMMITMENTS AND CONTINGENCIES - Narrative (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Lease renewal term	5 years
Remaining amount committed	$ 21.3	$ 20.7
Loss contingency accrual	$ 3.1	$ 3.2
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term	1 month
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	11 years

v3.23.2

COMMITMENTS AND CONTINGENCIES - Rental Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 18, 2022	Jun. 30, 2023	Jun. 18, 2022
Lessor, Lease, Description [Line Items]
Rental income	$ 8,683	$ 6,274	$ 16,372	$ 12,251
Environmental Services
Lessor, Lease, Description [Line Items]
Rental income	8,072	6,265	15,639	12,228
Oil Business
Lessor, Lease, Description [Line Items]
Rental income	11	9	17	23
Industrial and Field Services
Lessor, Lease, Description [Line Items]
Rental income	600	0	716	0
Parts Cleaning
Lessor, Lease, Description [Line Items]
Rental income	8,568	6,233	16,234	12,172
Parts Cleaning | Environmental Services
Lessor, Lease, Description [Line Items]
Rental income	7,968	6,233	15,518	12,172
Parts Cleaning | Oil Business
Lessor, Lease, Description [Line Items]
Rental income	0	0	0	0
Parts Cleaning | Industrial and Field Services
Lessor, Lease, Description [Line Items]
Rental income	600	0	716	0
Property
Lessor, Lease, Description [Line Items]
Rental income	115	41	138	79
Property | Environmental Services
Lessor, Lease, Description [Line Items]
Rental income	104	32	121	56
Property | Oil Business
Lessor, Lease, Description [Line Items]
Rental income	11	9	17	23
Property | Industrial and Field Services
Lessor, Lease, Description [Line Items]
Rental income	$ 0	$ 0	$ 0	$ 0

v3.23.2

INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 18, 2022	Jun. 30, 2023	Jun. 18, 2022
Valuation Allowance [Line Items]
Provision for income taxes	$ 3,310	$ 7,733	$ 8,929	$ 12,182
Effective income tax rate, percent	27.70%	27.00%	26.10%	26.40%
Uncertain tax positions
Valuation Allowance [Line Items]
Valuation allowance	$ 2,200		$ 2,200
Foreign Net Operating Loss Carryforwards
Valuation Allowance [Line Items]
Valuation allowance	$ 700		$ 700

v3.23.2

SHARE-BASED COMPENSATION - Narrative (Details) - USD ($)				3 Months Ended	6 Months Ended
	Nov. 14, 2022	Sep. 21, 2022	Feb. 01, 2021	Jun. 30, 2023	Jun. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)					80,298
Share price			$ 21.77
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense				$ 6,300,000	$ 6,300,000
Weighted-average vesting period					1 year 8 months 12 days
Restricted stock | Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)					1 year
Restricted stock | Members of Management
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)					3 years
Restricted stock | Members of Management | Special Incentive Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)		3 years
Grants in period (in shares)	147,623
Shares expected to vest (in shares)	147,623
Performance-based vesting percentage	66.667%
Restricted stock | Members of Management | Special Incentive Program | Vesting period one
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	33.333%
Restricted stock | Members of Management | Special Incentive Program | Vesting period two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	33.333%
Restricted stock | Members of Management | Special Incentive Program | Vesting period three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	33.333%
Restricted stock | Mr. Recatto
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)			500,000
Vesting threshold (in dollars per share)			$ 5.00
Shares vested upon achievement of share price threshold (in shares)			0
Compensation expense					$ 100,000
Risk-free rate			0.29%
Expected dividend yield			0.00%
Expected volatility rate			53.07%
Restricted stock | Mr. Recatto | Vesting period one
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage					0.00%
Restricted stock | Mr. Recatto | Vesting period two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)					90 days
Vesting percentage					25.00%
Grant of restricted stock			$ 500,000
Restricted stock | Mr. Recatto | Vesting period three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage					50.00%
Restricted stock | Mr. Recatto | Provision for possible accelerated vesting of award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)					180 days
Vesting percentage					50.00%
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period	3 years
Time Based Restricted Stock | Mr. Recatto
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)			90 days
Compensation expense				200,000
Unrecognized compensation expense				$ 1,300,000	$ 1,300,000

v3.23.2

SHARE-BASED COMPENSATION - Restricted Stock Compensation/Awards (Details) - Restricted stock - USD ($) $ in Thousands	1 Months Ended								6 Months Ended
	May 30, 2023	Feb. 28, 2023	Nov. 30, 2022	Apr. 30, 2022	Feb. 28, 2022	Feb. 28, 2021	Feb. 29, 2020	Apr. 30, 2018	Jun. 30, 2023	Jun. 18, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Expense									$ 6,300
April, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted (in shares)								350,000
Compensation Expense									0	$ 380
Unrecognized Expense									0	0
February, 2020 | Members of Management
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted (in shares)							41,138
Compensation Expense									0	40
Unrecognized Expense									0	47
February, 2021 | Members of Management
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted (in shares)						35,898
Compensation Expense									104	103
Unrecognized Expense									103	345
February, 2021 | Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted (in shares)						500,000
Compensation Expense									502	1,067
Unrecognized Expense									1,334	2,814
February, 2022 | Members of Management
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted (in shares)					75,355
Compensation Expense									249	245
Unrecognized Expense									735	1,303
April, 2022 | Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted (in shares)				17,082
Compensation Expense									0	234
Unrecognized Expense									0	246
February, 2023 | Members of Management
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted (in shares)		66,024
Compensation Expense									310	248
Unrecognized Expense									1,552	0
November, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted (in shares)			147,623
Compensation Expense									524	0
Unrecognized Expense									2,339	0
May 2023 Member | Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted (in shares)	14,274
Compensation Expense									280	0
Unrecognized Expense									$ 200	$ 0

v3.23.2

SHARE-BASED COMPENSATION - Restricted Stock Vesting Schedule by Percentage (Details)	6 Months Ended
	Jun. 30, 2023 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested (in shares) | shares	99,487
Mr. Recatto | Restricted stock | Less than $5 per share increase
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in stock price from employment commencement date (in dollars per share) | $ / shares	$ 5
Total Percentage of Restricted Stock Shares to Be Vested	0.00%
Mr. Recatto | Restricted stock | $5 per share increase
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in stock price from employment commencement date (in dollars per share) | $ / shares	$ 5
Total Percentage of Restricted Stock Shares to Be Vested	25.00%
Vested (in shares) | shares	125,000
Mr. Recatto | Restricted stock | $10 per share increase
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in stock price from employment commencement date (in dollars per share) | $ / shares	$ 10
Total Percentage of Restricted Stock Shares to Be Vested	50.00%
Vested (in shares) | shares	250,000
Mr. Recatto | Restricted stock | $15 per share increase
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in stock price from employment commencement date (in dollars per share) | $ / shares	$ 15
Total Percentage of Restricted Stock Shares to Be Vested	75.00%
Vested (in shares) | shares	375,000
Mr. Recatto | Restricted stock | $20 or more per share increase
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in stock price from employment commencement date (in dollars per share) | $ / shares	$ 20
Total Percentage of Restricted Stock Shares to Be Vested	100.00%
Vested (in shares) | shares	500,000

v3.23.2

SHARE-BASED COMPENSATION - Restricted Stock Rollforward (Details)	6 Months Ended
	Jun. 30, 2023 $ / shares shares
Number of Shares
Nonvested shares outstanding at Beginning of Period (in shares) | shares	728,693
Grants in period (in shares) | shares	80,298
Vested (in shares) | shares	(99,487)
Forfeited (in shares) | shares	(28,797)
Nonvested shares outstanding at End of Period (in shares) | shares	680,707
Weighted Average Grant-Date Fair Value Per Share
Nonvested shares outstanding at Beginning of Period (in dollars per share) | $ / shares	$ 21.83
Granted (in dollars per share) | $ / shares	37.08
Vested (in dollars per share) | $ / shares	25.51
Forfeited (in dollars per share) | $ / shares	21.95
Nonvested shares outstanding at End of Period (in dollars per share) | $ / shares	$ 25.79

v3.23.2

SHARE-BASED COMPENSATION - Employee Stock Purchase Plan (Details) - Employee Stock Purchase Plan - Employee stock	3 Months Ended
	Jun. 30, 2023 $ / shares shares
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares available employee stock purchase plan (in shares)	31,438
Issuance of common stock – ESPP (in shares)	5,070
Weighted average fair value per share ESPP (in dollars per share) | $ / shares	$ 35.24

v3.23.2

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 18, 2022	Jun. 30, 2023	Jun. 18, 2022
Earnings Per Share [Abstract]
Net income	$ 8,642	$ 21,107	$ 25,231	$ 33,985
Weighted average basic shares outstanding (in shares)	23,681	23,489	23,665	23,482
Dilutive shares for share–based compensation plans (in shares)	250	155	233	158
Weighted average diluted shares outstanding (in shares)	23,931	23,644	23,898	23,640
Net income per share: basic (in dollars per share)	$ 0.36	$ 0.90	$ 1.07	$ 1.45
Net income per share: diluted (in dollars per share)	$ 0.36	$ 0.89	$ 1.06	$ 1.44

v3.23.2

FAIR VALUE MEASUREMENTS - Assets Measured on Recurring Basis (Details) - Recurring $ in Millions	Jun. 30, 2023 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments at fair value	$ 15.2
Quoted prices in active markets (Level 1)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments at fair value	0.0
Significant other observable inputs (Level 2)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments at fair value	0.0
Significant unobservable inputs (Level 3)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments at fair value	15.2
Significant unobservable inputs (Level 3) | Retriev
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments at fair value	$ 3.0

v3.23.2

SUBSEQUENT EVENTS (Details) - Heritage-Crystal Clean, Inc - Subsequent event - JFL-Tiger Acquisition Co.Inc	Jul. 19, 2023 USD ($) $ / shares
Subsequent Event [Line Items]
Share price (in dollars per share) | $ / shares	$ 45.50
Adoption voting percent	75.00%
Termination fee	$ 42,331,515
Superior proposal termination fee	23,584,701
Parent Termination Fee	$ 72,568,311

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