At 3:28 p.m. Aug. 12, volunteer firefighters responded to the area of 2495 Davis Road, Waldorf, for a mulch fire that was spotted by a passing motorist.
Maryland Deputy Fire Marshal John Nelson reported on Monday that a fire started in a mulch pile and spread to consume a dump truck and a bull dozer.
It took 20 firefighters from Waldorf, Bryans Road, and Potomac Heights 20 minutes to control the blaze, which was ruled as accidental.
The damage was estimated at $30,000.
Officials with the Maryland Department of Natural Resources Forestry Division also responded for the investigation.