(from Wikipedia)      
The Graniteville train disaster is an American rail disaster that occurred on January 6, 2005, in Graniteville, South Carolina. The disaster occurred at roughly 2:40 a.m. Eastern Standard Time when two trains, owned by Norfolk Southern, collided near an Avondale Mills plant in Graniteville.^[1] One train, Norfolk Southern train number P22, was parked on a siding near the Avondale Mills plant; due to an improperly-lined railroad switch, the other train, train number 192 which was transporting chlorine gas, sodium hydroxide and cresol, was diverted into the siding and collided with the parked train. The collision derailed both locomotives and 16 of train 192's 42 freight cars and derailed the locomotive and one of P22's two freight cars; one of 192's tank cars loaded with chlorine ruptured, which resulted in the release of at least 90 tons of the gas into the environment. Ten people died (nine at the time of the accident, one later due to chlorine inhalation), and at least 250 people were treated for chlorine exposure.

5400 residents within a mile of the crash site were forced to evacuate for nearly two weeks while HAZMAT teams and cleanup crews decontaminated the area.