The people of Hungary are dealing with red toxic sludge from an aluminum factory's reservoir that is now flowing into the Danube River. Experts say the same thing could happen in the U.S.

Thick, red, toxic mud covers the landscape of the village of Kolantar like a mask.

Four people were killed when a reservoir's containment wall collapsed at a nearby metals plant Monday.

At least 34 homes in the town have been deemed unlivable. Residents fear their land is ruined and now they worry about the dust that will be left behind once the sludge dries.

"If you inhale it into the lungs, it can really cause health problems, because it consists of heavy metals," said Jarvor Benedek of the Department of the Hungarian Parliament.

The sludge has also reached Europe's mighty Danube River. From Hungary, the river flows through six countries before emptying into the Black Sea.

It seems unthinkable, but toxic disasters are a possibility in the U.S. too. Coal ash, which is a byproduct of coal power plants, contains heavy metals like lead and mercury. Also, more than 1,000 hazardous waste dumps, known as 'superfund sites' by the federal government, are actively used in every state in the nation.