Fire crews battled a blaze Saturday afternoon at the RSU 20 bus garage on Prospect Street in Searsport.
The call came in at 3:35 p.m., and when firefighters arrived, they found heavy smoke coming from the peak of the steel-clad building, according to Searsport Fire and EMS.
A section of the roof was compromised, forcing crews to operate in defensive mode, the department said. The fire was brought under control at about 6 p.m.
One school bus and one in-service pickup truck were inside the building at the time of the fire, along with two other vehicles undergoing long-term repairs. All four vehicles were destroyed, officials said.
Some RSU 20 bus drivers who came to the scene moved buses away from the building. Firefighters were able to use one of the buses as a place to warm up and eat during the response.
The Maine Fire Marshal’s Office is investigating the cause of the fire, which has not yet been determined.
Mutual aid was provided by Belfast, Stockton Springs, West Frankfort, and Bucksport fire departments.
Correction: An earlier version of this story indicated that no vehicles were damaged in the fire.