Brazil's federal police have filed formal charges against three mining firms Samarco, Vale and BHP Billiton, along with seven executives, for environmental crimes in connection to a major dam collapse and subsequent mine waste spill that occurred in November 2015.

Calling the dam's collapse the worst environmental disaster in the nation's history, the government of Brazil is suing the companies for $5.2 billion to compensate for damages to victims and to clean up the waste, according to Agence France-Presse.

Samarco, which operates the Fundão tailings dam, is a joint undertaking between Vale and the Australian company BHP Billiton, the world's largest mining firm, according to the Latin American Herald Tribune. The companies are accused of negligence that led to the eruption of the dam's waste reservoir, which unleashed a 530-mile toxic mudflow in waterways through two Brazilian states and along a stretch of the Atlantic coastline, The Daily Mail describes. The village of Bento Rodrigues was almost entirely buried during the mudslide.

It is estimated that 60 million cubic meters of iron mining waste and toxic sludge was released by the mine's failure, according to TeleSUR, and at least 17 people were killed. Two people are still missing due to the disaster.

In a press release, Samarco stated that it "did not agree with the charges against its executives because until now there has been no technical study to determine the cause of the accident," reports TeleSUR. The Brazilian police also submitted charges against the engineering company VogBR, which stated in a report in 2015 that the dam was in a stable condition.

Brazil's environmental law allows for potential prison sentences of up to five years for environmental destruction that "causes or may cause damage to human health or cause the death of animals or significant destruction of plant life," the AFP explains.

The investigation into the disaster is ongoing, with the potential of further charges being filed.