Rail cars carrying hazardous material derailed and burst into flames in a remote area of North Dakota on Friday 5 July.
Emergency officials say no one was hurt in the incident and added that the threat to those living nearby appeared to be minimal.
A CPKC train with 29 cars derailed at around 3:45am and flames were seen raging at the site hours later.
The enflamed railcars were mostly extinguished by Saturday.
Emergency officials now confirmed the contents of the derailed cars included anhydrous ammonia, methanol and plastic pellets.
The train derailed in a marshy area surrounded by farmland that is about 140 miles northwest of Fargo.
