The incident occurred at Trenton in rural South Carolina on Friday night at 8:30 p.m.
Ammonia is corrosive and it is dangerous to humans. Exposure to ammonia will cause burning of eyes, nose, throat, respiratory tract.
Derrick Becker, public information officer, for the South Carolina Emergency Management said that no injuries have been reported after the crash. He said, as a precautionary measure, evacuations have been made.
The officials said that one of the Norfolk Southern tankers had been carrying ammonia nitrate and one had been carrying anhydrous ammonia.
Total of 15 cars had been derailed and one of them carrying ammonia nitrate derailed.
Aiken County Hazmat officials responded to the scene immediately and no harmful spills have been detected by the officials.
An eyewitness confirmed WATG, that after hitting a tree which had fallen on the rail racks, the train derailed.
The officials were unable to confirm the cause of the derailment and investigation will provide the answer.
Investigation will be taken by National Transportation Safety Board and Norfolk Southern officials.