State police said crews were working to clear U.S. Highway 190 which was blocked by the accident. The Union Pacific train went off the tracks Sunday around 3:30 p.m.
Company spokeswoman Raquel Espinoza said one of the railcars was leaking sodium hydroxide, which can cause injuries or even death if it is inhaled or touches the skin. The other was leaking lube oil. But state police said the leaks were contained.
Gov. Bobby Jindal flew into St. Landry Parish on Sunday night to inspect the scene.
"Anytime you have chemicals leaking into the environment, that's a serious issue," Jindal said. "Nobody knows the extent of the damage. We'll get that in the next 24 hours."
Another damaged car was carrying vinyl chloride, Espinoza said, but it was not leaking. Vinyl chloride is extremely flammable.
There were two people on the train, an engineer and a conductor. They were not hurt. Espinoza said a man who was near the derailment initially did not want to go to the hospital in an ambulance, but decided later to go get checked out for a burning sensation in his eyes.
"We're bringing in equipment to make sure we move all of this in the safest manner," Espinoza said.
The railroad company doesn't know what caused the derailment. Espinoza said the railroad ties were renewed in 2011 and the track was inspected about three hours before the accident.
The track runs parallel to U.S. Highway 190. State police said it would be closed for at least two days. Traffic was also being diverted from the evacuation zone.
St. Landry Parish President Bill Fontenot said evacuated residents could go a theater the local government owns if they needed a place to stay. The Delta Grand Theater has no fixed seating, so cots can be easily set up, he said.
"I think we've got about 30 individuals there now. Some are still trying to find relatives or friends" to stay with, he said late Sunday.
Copyright 2013 The Associated Press.