Work is under way to clean up rail cars carrying hazardous materials that fell into the Yellowstone River in southern Montana after a bridge collapsed over the weekend, officials said.
Montana Rail Link is developing a clean-up plan and is working with its unions and BNSF Railway to reroute freight trains in the area to limit disruption of the supply chain, Beth Archer, a spokesperson for the US Environmental Protection Agency, said in a joint statement issued with the Montana Department of Environmental Quality and Montana Rail Link.
Contractors and a large crane were on site to stabilise and remove cars from the river once a plan is set, officials said.
Some rail cars that did not go off the tracks were removed from the area, and two cars carrying sodium hydrosulphide had their contents transferred to other cars and moved to safety, Ms Archer said.
Montana Rail Link will be responsible for all clean-up costs, chief executive Joe Racicot told a news conference.
Sixteen cars derailed, and 10 of them ended up in the river downstream from Yellowstone National Park Saturday morning.
Six mangled cars that carried hot asphalt, three holding molten sulphur and one with scrap metal remained in the rushing water on Monday in an area surrounded by farmland near the town of Columbus, about 40 miles west of Billings.
Two of the cars were submerged, and a dive team was deployed to gather more information, Ms Archer said in a statement.
Joni Sandoval, the EPA on-scene coordinator, told a news conference her agency has invited experts from federal and state fish and wildlife agencies to come to the site to assess how the derailment has affected wildlife.
The asphalt and sulphur solidified and sank in the cold water, officials said.
Some asphalt globules were found downriver, but they are not water soluble and are not expected to impact water quality, the statement said.
Water samples taken on Saturday showed the materials from the derailment had not affected water quality, Shasta Steinweden of the state Department of Environmental Quality said.
The tests showed no presence of petroleum and sulfur levels were consistent with upstream water samples, she said.
Results from samples taken Sunday and Monday were still pending.
The cause of the collapse was under investigation.
Part of the train had crossed the bridge before it failed, and some cars at the back remained on stable ground at the other end.
No injuries were reported.
The collapse also cut two major fibre-optic lines.
Global Net said late on Sunday that it had developed a temporary workaround.
Company officials did not return a call on Monday seeking further information.
The White House was monitoring the situation and was prepared to offer any federal help that might be needed, spokesperson Karin Jean-Pierre said.
The derailment comes just over four months after a freight train derailed near East Palestine, Ohio, sparking a fire that led to evacuations and the eventual burning of hazardous materials to prevent an uncontrolled explosion.
Freight railcar inspections are happening less often, union officials testified last week during a congressional hearing about the Ohio derailment.
Ms Jean-Pierre said the US Department of Transportation is looking into ways to prevent derailments.
The government has been “all hands on deck”, she said.
