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.from CSX: Md. train explosion caused by chemical cargo
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.
Sumwalt said late Tuesday that the collision occurred at a private crossing where the only marking was a stop sign. He said it wasn't clear why the truck was crossing the tracks or whether it was authorized to be there.
The truck driver, 50-year-old John J. Alban Jr., remained in serious condition Wednesday at Shock Trauma in Baltimore, a hospital spokeswoman said. Two CSX workers aboard weren't hurt.
I find it difficult to believe that this was an accident. It's intriguing that it occurred almost precisely on the Earth Grid (see image - the actual location of the incident is slightly NE of Baltimore) on 5/28/2013, i.e. 33/6, i.e. 6-6, and it just happened to contain this volatile combination of chemicals (which it appears should have been kept further apart from each other). Note that it occurred in the context of a recent rash of terrifying "non-terrorist" incidents, including a major bridge collapse caused by an "accident" (interestingly, Al Qaeda hasn't taken out any bridges, although it would evidently be easy) and a couple of other train crashes.