By Tuesday, about 35.3 million cubic feet of sludge had poured from the reservoir, flooding a 16 square mile area, Environmental Affairs State Secretary Zoltan Illes told the state news wire MTI. He called the spill an "ecological catastrophe."

Dozens of villagers were burned when the caustic material seeped through their clothing. Two women, a young man and a 3-year-old child were killed, and health officials said two of the injured were in critical condition.

Because chemical burns can take days to emerge, seemingly superficial injuries can turn deadly as they penetrate deeper tissue, Dr. Peter Jakabos of Gyor Hospital told state TV.