The reservoir of an alumina plant in western Hungary burst on Monday, flooding several towns with towering waves of red sludge. Two people died, seven were missing and several dozen were injured, rescue services said.
The spill of an estimated 600,000-700,000 cubic meters (yards) of sludge affected several localities such as Kolontar and Devecser near the Ajkai Timfoldgyar plant in the town of Ajka, 160 kilometers (100 miles) southwest of Budapest, the capital.
In Devecser, the sludge flooded some 400 homes, and 40 people had to be rescued in the neighboring town of Somlovasarhely. In Kolontar, the rushing sludge reached a height of two meters (6.5 feet).
The sludge, a waste product in aluminum production, contains heavy metals and is toxic if ingested, the National Disaster Management Directorate said.
Some 120 people, including six who were seriously hurt, were treated by medical staff. Two of the injured were in life threatening condition. The most common injuries caused by the caustic sludge were burns on the skin and eyes, said Jozsef Czirner, the regional rescue service director.
The disaster agency said 390 residents had to be temporarily relocated and 110 were rescued from the flooded towns.
Army vehicles, two helicopters and some 40 soldiers were sent to assist with rescue efforts, state news wire MTI reported citing the defense ministry.
Police were also investigating the cause of the incident, MTI said.