Crews burn off remaining chemicals

Fire officials started a controlled burn Wednesday of thousands of gallons of a flammable liquid left over after a derailment set off a huge chemical fire that led to evacuations and the closing of a busy highway.

A dozen tanker cars derailed Tuesday morning and spilled various chemicals that caught fire, pouring out flames and huge clouds of smoke.

Officials urged residents within a mile to evacuate. No serious injuries were reported but about two dozen people near the crash site south of Louisville checked themselves into a hospital and were released after checkups, authorities said. An 18-mile stretch of nearby Interstate 65 was closed for about 11 hours.

On Wednesday, three other tank cars that did not burn in the original blaze were drained of their cargo of 90,000 gallons of butadiene, a chemical used to make synthetic rubber. That liquid was channeled into a freshly dug pit and set afire because authorities were concerned about the safety of removing the three tank cars while they remained filled.

The chemicals spilled when the 12 train cars derailed Tuesday were cyclohexane, methyl ethyl ketone, butadiene and alcohol, said Gary Sease, a CSX Corp. spokesman. Officials said they considered the substances toxic, but said they break down when burned.

Art Smith of the U.S. Environmental Protection Agency said early air quality readings showed no signs of hazardous compounds. He said nearby waterways would be monitored.

Mark Rosenker, chairman of the National Transportation Safety Board, said federal investigators would inspect the track for "nicks or abrasions."

"This will give us an idea if the train struck anything," Rosenker said.

The track had been inspected by CSX inspectors on Monday, he said.

Investigators had downloaded information from the train's data recorder and sent it to Washington for reading. Results of toxicology tests on the two-man crew were expected within two weeks, he said.

The train _ with four locomotives and 80 cars _ had been headed to Louisville from Birmingham, Ala.

It was the second fiery train crash in Kentucky in two days. On Monday, four runaway rail cars struck two parked locomotives in central Kentucky, catching fire and spilling a chemical that prompted a limited evacuation.