The Hungarian aluminum plant whose burst reservoir sent tons of toxic red sludge through several towns is set to resume production Friday. Nine people were killed and wildlife in the Marcal river was wiped out after the accident.
Evacuated residents are getting ready to return to their villages, despite warnings from environmental groups that the area may not be safe.
Reuters news agency reports that disaster officials have advised those returning to wear dust masks at all times.
New dam walls have been built around the damaged retaining walls to prevent any further spills.
At least 100 people were injured in the October 4 disaster.
The government has taken over the MAL Zrt plant.
Greenpeace, the environmental group, called the decision to allow residents to return to their homes "irresponsible" because the exact cause of the accident has not yet been determined.
A partial collapse of a reservoir wall released about 600,000 cubic meters of red sludge into several communities and also polluted tributaries of the Danube river.
Authorities had feared additional cracks found in the northern reservoir wall could crumble and release another 2.5 million cubic meters of chemical waste if it crumbled.
The red sludge is a byproduct of bauxite, a material used in manufacturing aluminum.