A Billings municipal garbage truck dropped a load of trash on Rimrock Road after materials ignited and caused an explosion Monday morning, causing several blocks to be closed to traffic for several hours.
The garbage truck had just finished picking up a load of refuse from the campus of Rocky Mountain College, city solid waste division superintendent Vester Wilson said, when "it just exploded."
"There was a 'boom,'" Wilson said, adding that the driver looked in his side-view mirror to see flames erupting from the truck. "He just dropped it in the road, which is what he's supposed to do."
Billings Fire Department crews responded to the incident and hosed down the burning trash pile, while Billings police officers blocked off the street from 13th to 17th streets west.
Scorched pieces of trash were still scattered in the street near the intersection of Rimrock and Smokey Lane two hours after the explosion, which occurred around 10:30 a.m. Sanitation workers used brooms and shovels to scrape up the remaining pieces of trash, while a street sweeper washed away the remaining bits of detritus.
Wilson said incidents in which garbage trucks catch fire aren't too uncommon, typically occurring two or three times each year.
"More than likely we've got some chemicals or some fluids that got dumped in there" and ignited once they became mixed, he said.
Truck operators are directed to drop the loads of flaming garbage in the street to avoid destroying the vehicles, which cost about $330,000 apiece, Wilson said.
Spontaneous trash fires are one of the reasons residents are asked to dispose of chemicals by taking them to the landfill, where they are handled separately from other solid waste, Wilson said.
Billings police Sgt. Pat Curry stated in a social media post that the road had fully reopened as of 1:23 p.m.