KOLONTAR, Hungary  Just before he raced for refuge in the attic of his family’s home here on Monday at lunchtime, Krisztian Holczer called his mother at her job at a school near here.

“You won’t believe what is happening,” Mr. Holczer said he told her.

A wave of caustic red sludge had just poured in over the back fence and was descending rapidly over the backyard, smothering chickens and hares as well as a garden of flowers, peppers, grapes and tomatoes. It rose up until it covered the tiled front porch and leached in through the front door, dyeing the pristine white lace curtains red. Mr. Holczer, 34, escaped with burns on his feet from the dangerous muck.

The origin of the liquid was a nearby sludge reservoir holding the leftovers of the process that converts bauxite to aluminum. For more than 25 years, residents say, a Hungarian manufacturer, MAL Rt., the Hungarian Aluminum Production and Trade Company, has stored such waste at several artificial storage ponds in the region. Once a state-owned company, it was privatized in the 1990s like much of Communist-era industry in Eastern Europe.

Just after noon on Monday, a corner of the sludge reservoir broke, sending the goo into the surrounding countryside, turning four prosperous, picturesque villages into red-tinged towns out of science-fiction horror films.