December 15, 2006 - Marriottsville, Maryland: At 3:00am, 21 cars of a 91 car CSX freight train derailed - including a tank car carrying anhydrous ammonia.

Because the derailment happened in a rather remote location of the state, the Maryland Department of the Environment Emergency Response Team and other responders initally had difficult reaching the incident site.

While the tank car of ammonia did turn off, the structural integrity of the vessel was not compromised.

At 6:20pm, the incident was declared stable with the ammonia tank car righted from it's overturned position.

No one was harmed in the incident.