Kolontar, Hungary ? There was no stopping the avalanche of toxic red sludge: It smashed through the door of Kati Holczer’s house, trapping the mother and her toddler in a sea of caustic waste.

She saved her 3-year-old son, Bence, by placing him on a sofa that was floating in the muck. Then she called her husband Balazs, who was working in Austria, to say goodbye.

“We’re going to die,” she told him, chest-deep in the acrid mud.

After the terror came the pain: Holczer and her two rescuers were among dozens of villagers suffering from deep chemical burns following Monday’s spill.

Their fox terrier Mazli — his name means “Luck” in Hungarian — lay dead in the yard Wednesday, still chained to a stake. Luca, their Labrador, was swept away by the 9-foot-high wave of toxic waste that poured from a breached reservoir at a nearby alumina factory.

The ecological catastrophe that is threatening the Danube River — one of Europe’s main waterways — has left a trail of shattered lives.

On Wednesday, furious villagers, their shoes splattered with the caustic red mud, crowded around an official of the company blamed for the disaster and demanded compensation for destroyed homes, fields and livelihoods. Authorities have ordered a criminal inquiry into the accident, which killed at least four people, injured 120 and left three people missing.

After bursting from the reservoir and flooding three villages Monday, the sludge — a waste product of aluminum production that can contain heavy metals — ended up in the Marcal River, part of the tributary system feeding the Danube, some 45 miles to the north. Hundreds of people were evacuated.

Local streams were swollen Wednesday and tinted ochre by the sludge, and residents said they were empty of fish.