The Associated Press

LAFAYETTE, La. — Residents forced to flee a toxic chemical spill returned home, but a narrow evacuation perimeter remained around the site of a freight train derailment.

About 3,000 residents were allowed to return home Sunday as crews cleaned up hydrochloric acid that spilled when six train cars rolled off the tracks a day earlier. State police said about half of the 10,000 gallons of acid had been collected.

A one-mile evacuation radius was cut to 1,000 feet from the accident site, said State Police Trooper Stephen LaFargue. The reduced area includes only a few businesses. The restrictions probably would not be lifted for a couple of days, he said.

The Texas rail company that operated the train started an investigation and its findings will be submitted to the Federal Railroad Administration.

"A thorough investigation will take place. It could take a while," said spokesman Joe Faust of BNSF Railway.

Saturday's wreck spread a toxic cloud over Lafayette, a southern Louisiana city about 125 miles west of New Orleans. Five people, including two railroad workers, were sent to a hospital and treated after complaining of skin and eye irritation, state police said.

Hydrochloric acid can cause respiratory problems and skin and eye irritation.

The train had been headed to Lake Charles, near the Texas border, about 75 miles west of Lafayette, Faust said.

The derailment caused one of the six cars to leak the acid, which formed a yellowish pool. Cleanup crews used lime to neutralize the chemical, while contractors for the rail company excavated the acid for disposal.

All six rail cars were moved upright, and some were moved out of the contamination site, Trooper David Anderson said. "The stuff we're dealing with is bad — very bad stuff," he said.

The evacuees included 161 nursing home residents, about 35 of whom were taken to hospitals because they were too frail to be moved to other facilities, state officials said.

Faust said BNSF would reimburse evacuated residents for hotel and restaurant bills incurred during the evacuation.

The accident forced Amtrak's Sunset Limited from Los Angeles to detour around Lafayette and arrive about 90 minutes late in New Orleans on Sunday, said Amtrak spokesman Cliff Cole. Eleven passengers who had been bound for Lafayette and two other Louisiana stops were bused out of Houston, he said.