Disaster agency spokeswoman Gyorgyi Tottos says a crack on the northern wall of the metals plant’s storage pool holding a byproduct of aluminum manufacturing widened by around half an inch (1.5 centimeters) on Thursday.
Tottos says plans are still on for residents of Kolontar, the town closest to the 24-acre (10-hectare) reservoir, to return to their homes starting Friday and a new protective wall will be in place.
The red sludge that spilled last week, killing nine people, is a highly caustic byproduct of the production of alumina, which is used to make aluminum.