ROSEDALE, Md. (AP) — Train operator CSX Transportation on Wednesday pointed to a hazardous chemical in a rail car as the source of an explosion on a derailed train near Baltimore that sparked a fire, rattled homes and damaged buildings. A company spokesman said officials still weren’t sure what caused the sodium chlorate to explode in the first place, but it ignited another chemical in a second car.
Authorities are continuing to look into the cause of Tuesday’s incident. Robert Sumwalt, a member of the National Transportation Safety Board, said investigators were examining evidence on the scene and reviewing train video that might show the collision with a garbage truck that set off the incident. But he said they had not reached any conclusions.
Sumwalt said at a news conference Wednesday that the freight train was traveling 49 mph and that the engineer blew a whistle three times before it collided with the truck.
The train hit the right rear axle of the truck as it was crossing the tracks around 2 p.m. Tuesday, Sumwalt said. He added that the locomotive applied its emergency brakes and traveled nearly a mile before coming to a stop. Fifteen cars derailed, including three of the four cars that were carrying hazardous materials.
The chemical that exploded was sodium chlorate, which is highly volatile. Sumwalt said the explosion, which damaged nearby buildings and shook homes miles away, occurred 5 minutes and 23 seconds after the initial collision. The sodium chlorate was in powder form and was being hauled in a covered hopper car. Another chemical burned for nearly 10 hours after the crash.
CSX spokesman Gary Sease said the sodium chlorate in a derailed car near the front of the train exploded, igniting terephthalic acid in another derailed car.
Sodium chlorate is used mainly as a bleaching agent in paper production. Oklahoma State University chemist Nick Materer said it could make for a potentially explosive mixture when combined with an incompatible substance such as spilled fuel.
Another chemist, Darlene Lyudmirskiy, of Spectrum Chemical Manufacturing Corp. in Gardena, Calif., said such a mixture would be unstable and wouldn’t need even a spark to cause a reaction.
“If it’s not compatible, anything could set it off,” she said.
The railroad said in a news release Wednesday that it continues to work with state and federal environmental officials to “clean up products released in the derailment.” The company said it is conducting air, water and soil sampling and sharing that information with officials.
On Wednesday afternoon, workers were using heavy cranes to move the damaged rail cars, and an excavator was picking up broken pieces of track. The mangled truck lay on its side on the side of the railroad tracks, its contents littering the ground. Next to the track, the corrugated metal walls of a warehouse were bent and warped.
Among the buildings that sustained the most damage was a training facility for a plumbers and steamfitters union a few hundred yards away from the explosion site. Only a handful of employees were in the building at the time of the blast, and all but one rushed outside to see what had happened. They heard the crash first, followed by the derailment, then saw a plume of smoke.
Al Clinedinst, the training director for the facility, said he and a colleague drove closer to the derailment scene before the explosion to see if they could help, but they were turned back by the overwhelming heat.
“It was paint-bubbling hot,” he said.