FERGUS FALLS (Valley News Live) -- The Fergus Falls Fire Department battled sub-zero temperatures to put out a construction trailer fire Friday.
The trailer, engulfed in flames when firefighters arrived, contained two 100-pound propane cylinders.
Firefighters cooled the tanks and extinguished the trailer fire in 10 minutes, but one of the propane tanks continued to burn off due to a leak.
Fire crews remained on the scene for 90 minutes while the propane burned.
Officials said the fire likely was caused by a heating unit.