More than 5,000 Tennessee residents were evacuated after a freight train carrying “highly flammable and toxic gas” derailed and caught fire, officials said.
After burning for hours, the fire in the train containing a hazardous liquid has been extinguished on a Blount County track, just outside Knoxville.
Firefighters evacuated people within a mile-and-half radius of the site as a precaution. An evacuation zone is in place for up to 48 hours, the fire department said.
Local police said ten officers were hospitalised after breathing in fumes at the site.
Firefighters had been trying to extinguish the fire and hose down neighbouring train cars to cool them.
The smoke has stopped rising from the site and firefighters have been able get close to the site because of the heat, officials said.
Blount County Mayor Ed Mitchell said shortly before 6 p.m. local time that he and others had visited the site and the smoke had stopped, AP reported.
The train was pulling 57 carriages of mixed freight from Ohio to Georgia when it derailed just before midnight on Wednesday, the train's operators CSX said in a statement.
Acrylonitrile is a chemical compound used to manufacture plastics. If inhaled in high levels the substance can cause membrane irritation, headache, nausea and kidney irritation.