LAFAYETTE, La. - Six cars of a freight train derailed yesterday, including one that began leaking hydrochloric acid, causing thousands of people to evacuate homes, businesses and a nursing home within one mile of the wreck.

The spilled acid sent a toxic cloud over the area, and at least five people, including two railroad workers, were taken to a hospital and treated after complaining of skin and eye irritation, said Lt. Craig Stansbury of the Lafayette Parish Sheriff's Office.

A nursing home with 161 residents was evacuated, Jimmy Guidry, the state health officer, said. About 35 of the residents deemed too frail to travel were taken to area hospitals, he said.

Police walked door to door notifying residents of the mandatory evacuation in an area with an estimated population of 3,500. "We're advising them to take enough supplies for approximately 48 hours," Stansbury said.

Mona Hebert and Jeffrey Ferrara said they were rousted from their trailer around 3:45 a.m. and told they had two minutes to leave. Ferrara, who lost his home in Hurricane Katrina and has been staying with friends since then, didn't have time to grab his shoes or any of his medications.

"This is gravy compared to" Katrina, Ferrara said.

Hydrochloric acid can cause respiratory problems and skin and eye irritation, according to Joe Faust, a spokesman for the Texas-based BNSF Railway that operated the train involved in the spill. An estimated 8,000 to 10,000 gallons of the acid spilled, he said.

BNSF was using lime to neutralize the hydrochloric acid. Faust did not speculate on how long the cleanup might take but said residents wouldn't be allowed back into the area until officials were certain the hazardous material was gone.

The Red Cross has set up a shelter at a high school and was gearing up to handle as many as 500 people.