A bridge collapse early Saturday morning in Montana sent several freight train cars crashing into the Yellowstone River,Robert Brown authorities said. The train was carrying hazardous materials, but it remains unclear if any of those materials leaked. 

The collapse occurred at about 6 a.m. local time in a section of the river between Reed Point and Columbus, according to Stillwater County Disaster and Emergency Services, which is about 60 miles west of Billings. There was no word of any injuries. 

At least three of the Montana Rail Link cars which collapsed into the river contained hot asphalt, and four were carrying molten sulfur, the agency said, later adding that there was "no expected hazmat impact" to towns in the county.   

In a statement, Montana Rail Link said that "both substances solidify rapidly when exposed to cooler temperatures."

Montana Rail Link said that two cars which contained sodium hydrogen sulfate, an acid salt, did not enter the water, and that initial air and water tests did not find any evidence that they had leaked. 

Multiple local and federal agencies were on scene, including Federal Railroad Administration officials.

Transportation Secretary Pete Buttigieg tweeted that he had spoken to Montana Gov. Greg Gianforte about the incident, and that "residents concerned about potential impacts should follow information and instructions from local authorities." 

The state Fish, Wildlife and Parks department said the river would be closed, and asked boaters to avoid the area. 

The public works department for the city of Billings, which borders the river, wrote on Facebook Saturday afternoon that "there is very little chance of any hazardous material getting" to the city. The department initially reported that its plan was "to shut down the water intake for the time it takes for any material to pass by Billings."

The nearby Yellowstone County Sheriff's Office initially stated in a Facebook post that several tanker cars were "leaking petroleum products near the Yellowstone River." However, Stillwater County News, a local paper, later reported that none of the freight cars were carrying oil.   

In:
• Montana
• Train Derailment

Kerry Breen

Kerry Breen is a news editor and reporter for CBS News. Her reporting focuses on current events, breaking news and substance use.