KOLONTAR, Hungary (Reuters) - Hungary declared a state of emergency in three counties on Tuesday, a day after a torrent of toxic red sludge from an alumina plant tore through nearby villages, killing four people and injuring 120.

The waste, produced during bauxite refining, poured through Kolontar and two other villages on Monday after bursting out of a containment reservoir at the Ajkai Timfoldgyar Zrt plant, owned by MAL Zrt.

On Tuesday, the Natural Disaster Unit (NDU) said four more villages were affected and put the death toll at four. Six people were missing.

Others suffered from burns and eye irritations caused by lead and other corrosive elements in the mud. The flood, estimated at about 700,000 cubic meters (24 million cubic feet), swept cars off roads and damaged bridges and houses, forcing the evacuation of about 400 residents.

“We have declared a state of emergency in Veszprem, Gyor-Moson-Sopron and Vas counties,” government spokeswoman Anna Nagy said. “In Veszprem county, it’s because that is the scene of the disaster and the sludge is headed toward the other two counties.”

Prime Minister Viktor Orban said the spill may have been caused by human error.

“We have no information at our disposal... we do not know of any sign which indicates that this disaster would have natural causes,” Orban said. “And if a disaster has no natural causes, then it can be considered a disaster caused by people. We suspect that this may be the case.”

He said tests had shown there was no threat of radiation.

People in Kolontar, which lies closest to the burst reservoir, were trying to recover their belongings but police were not yet letting them back into their flooded homes.

“My bathtub is full of this sludge ... when the dam burst, it made a terrible noise. I was in my yard, and I had to run up the steps to the porch but the water was rising faster than I could run,” Ferenc Steszli, 60, told Reuters.

He said he escaped by standing on a table.

Farmland around the village was covered in the sludge and many livestock were killed.

Slideshow ( 11 images )

PROTECTING THE DANUBE

The disaster unit said clean-up crews were pouring plaster into a nearby river to help neutralize the spill and attempts were being made to prevent the sludge getting into the Danube, a major European waterway.

A Greenpeace expert said the impact from the mud spill could be much worse than a cyanide spill at Baia Mare in Romania ten years ago, when cyanide-tainted water was discharged from a gold mine reservoir, polluting the Tisza and Danube rivers.

“This disaster is seven times as large as the incident in Baia Mare. The ecological impact can be very wide and take a long time to neutralize because heavy metals and caustic soda form a very dangerous toxic mix,” Katerina Ventusova, a Greenpeace expert for toxics told Reuters at the scene.

Slideshow ( 11 images )

MAL Zrt said in a statement there had been no sign of the impending disaster and that the red sludge did not qualify as hazardous waste according to European Union standards.

The NDU defined the red mud on its website as: “A by-product of alumina production. The thick, highly alkaline substance has a caustic effect on the skin. The sludge contains heavy metals, such as lead, and is slightly radioactive. Inhaling its dust can cause lung cancer.”

It recommended people clean off the sludge with water to neutralize the substance.