(Reuters) - Investigators on Friday were looking into what caused a freight train carrying flammable and toxic gas to derail and catch fire in Tennessee, forcing the day-long evacuation of 5,000 people, officials said.
The flames that engulfed a car of the CSX Corp train in Blount County, near Maryville in eastern Tennessee, late Wednesday were extinguished by late Thursday, CSX said. The tank car was loaded with about 24,000 gallons of acrylonitrile, a hazardous material used in manufacturing plastics and other industrial processes.
Noxious fumes sent more than 80 people to the hospital, including 10 law enforcement officers who were kept overnight, said Blount County Sheriff's spokeswoman Marian O'Briant.
The U.S. Environmental Protection Agency was testing air, soil and water samples and "so far everything is looking good there," O'Briant said. Residents were advised not to use well water.
"At noon today, we're going to let residents in the hot zone go back home, but we're going to do it by neighborhood," O'Briant said.
About 5,000 residents in a 1.5-mile radius of the derailment, which occurred at about midnight on Wednesday, were evacuated on Thursday. Blount County has urban and rural areas and is home to part of the Great Smoky Mountains National Park.
The cause of the derailment is under investigation by officials of the Federal Railroad Administration and CSX, the company said.
The train was en route from Cincinnati to Waycross, Georgia, when the tank car derailed, CSX said. The train was made up of two locomotives and 57 cars, including 27 carrying hazardous materials, according to the company.
A handful of the evacuees spent the night at a Red Cross shelter set up at a nearby high school, while the others stayed with friends, family and at area hotels. CSX said it was offering displaced residents lodging, drinking water and other assistance.
(Writing by Barbara Goldberg in New York; Editing by Ian Simpson and Jeffrey Benkoe)