Toxic mud has covered several towns in Brazil after a dam holding the mud collapsed earlier this month.
The mud has destroyed forests over a large area and also the village of Bento Rodrigues close to where the Fundao dam collapsed.
Around 600 people who live nearby have been in temporary accommodation since the accident.
The dam was used to hold waste water from iron production.
The toxic mud has even polluted the Atlantic Ocean along the Espirito Santo state coast.
A full investigation will be carried out, at the end summer 2016 after the Brazil's rainy season is over, to work out how big the impact the accident has been.