VALE Vale SA

RIO DE JANEIRO—A catastrophic dam failure that killed 19 people and polluted hundreds of miles of rivers in Brazil last year was the result of a mining company's repeated decision to prioritize production over safety, Brazil's Federal Police said Thursday.

Top executives at Samarco Mineraç ã o, the joint venture between global mining giants Vale SA and BHP Billiton Ltd., for years were aware of cracks and drainage problems at the so-called Fundã o tailings dam that collapsed Nov. 5, the police said.

"Don't call it an accident," Roger Lima de Moura, head of the Federal Police task force that investigated the disaster, said in an interview. The companies were "more than negligent," he said.

The risk was so high that company officials discussed purchasing and relocating the village of Bento Rodrigues, which was wiped out by a tsunami of mine waste after the dam broke, the authorities said. But rather than taking precautionary measures like halting production to reinforce Fundã o, the company cut spending and proceeded with a plan to increase output by 37%, the Federal Police added.

Brazil's Federal Police presented on Thursday the results of a seven-month investigation that included phone calls and text messages between Samarco executives, expert analysis and witness testimony. They requested formal charges against eight company officials, including former Chief Executive Ricardo Vescovi and a manager at Vale's nearby Alegria mine, for environmental crimes.

Samarco and Mr. Vescovi didn't immediately return emailed requests for comment.

Criminal proceedings against Samarco had been suspended for more than two months before a high court determined in late May that the case take place at the federal level. The accusations unveiled Thursday are part of an investigation into environmental crimes by Samarco. Federal prosecutors are carrying out a separate investigation into the human toll after police recommended charges of "qualified homicide" for the 19 deaths.

A separate civil case filed by federal prosecutors last month called for 155 billion Brazilian reais ($45.6 billion) in damages, comparing the fallout from Samarco's disaster to BP's Deepwater Horizon oil spill in the Gulf of Mexico in 2010.

Write to Paul Kiernan at paul.kiernan@wsj.com

(END) Dow Jones Newswires

June 09, 2016 18:35 ET (22:35 GMT)

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