Brazilian prosecutors have charged 21 national and foreign mining executives with manslaughter and other environmental crimes almost a year after a mine dam burst killed 19 people and polluted hundreds of miles of rivers and streams.

The office of the attorney general in the state of Minas Gerais says the group of mostly Brazilians also includes American, Australian and British board members and directors for the mining company Samarco and the two mining giants Vale of Brazil and BHP Billiton of Australia.

Federal prosecutor Jose Adercio Leite Sampaio said in a press conference on Thursday that the companies' representatives knew the basin of mine dump could burst but chose to ignore the risks to continue extracting iron ore in one of the richest deposits of the mineral.