Brazilian police in the state of Minas Gerais have accused six Samarco executives and a contractor of murder in connection with the deaths of 19 people caused by a burst tailings dam at a mine in November.
The Samarco chief executive at the time of the incident, Ricardo Vescovi, was among those accused.
In Brazil only prosecutors, and not police, can formally bring criminal charges but public accusations often anticipate charges being filed.
The police, in a statement, accused the mine executives of "qualified homicide", the murder charge that carries the heaviest sentence in Brazil of 12 to 30 years in prison.
They said the rupture had been caused by over-filling the dam, combined with a lack of monitoring and faulty equipment.
Samarco, a joint venture of Vale SA and BHP Billiton, said in a statement it considers the accusations "misguided" and will wait for a court decision before taking appropriate action.
The company is still investigating what caused the breach.
The deadly dam burst is considered Brazil's worst environmental disaster, polluting a major river with thick red sludge which reached the Atlantic Ocean.
It also destroyed the village of Bento Rodrigues, forcing hundreds to flee their homes and killing 17 people. Two people are still missing but the police said they are now considered fatalities.