WYOMING – A train derailment on the Union Pacific Railroad has reportedly killed one, injured two others and a fourth person is still unaccounted for.

The accident occurred last night around 8pm just west of Cheyenne, Wyo. Cleanup crews and investigators are on-scene this morning resulting in the closure of Exit 345 (Warren Road) on Interstate 80 in Laramie County, as well as the truck parking area at that interchange.

WYDOT is reporting the I-80 service road is also closed to eastbound traffic at Exit 342 (Harriman Road), though traffic accessing the quarries in that area is allowed.

After an investigation by the UPRR’s safety team, cleanup work will begin and could take as long as 10 days, according to railroad representatives. The closure will remain in place as cleanup continues.