(Reuters) - A bridge in Montana collapsed into the Yellowstone River early on Saturday, landing multiple rail cars in the water, officials said.
Montana Rail Link, the company operating the train, said in a statement that "several hazmat cars" plunged into the river. No injuries were reported among the train crew, it added.
The rail cars were carrying asphalt and molten sulfur, substances that quickly solidify when they come in contact with cooler temperatures, the company said.
Two cars transporting sodium hydro sulfate, an acid salt, did not enter the water and initial air quality assessments indicate the chemical was not released from the cars, Montana Rail Link said.
Multiple local, state and federal agencies were coordinating the response and working to determine what caused the derailment. Authorities were "unsure" what happened first - the derailment or bridge collapse, local media reported.
"Water treatment plants, irrigation districts, and industrial companies are taking appropriate precautions," the Yellowstone County's Sheriff's Office in Billings said in a Facebook (NASDAQ:META) post.
The incident took place at about 6:45 a.m. MTD (1200 GMT) as the train carrying the tankers was traveling westbound near Reed Point through the sparsely populated countryside of Stillwater County, according to Montana Rail Link.
Montana Fish, Wildlife & Parks said the derailment and bridge collapse led to the closure of parts of the Yellowstone and Stillwater Rivers.