A fire burned 37 acres in windy conditions in Bay Point before being contained Monday afternoon, Contra Costa County Fire Protection District officials said.
Firefighters responded around 2:30 p.m. to a report of a fire in an area bounded by San Marco Boulevard, Bailey Road and West Leland Road, Fire Marshal Robert Marshall said.
Marshall said the single-alarm fire grew in a relatively inaccessible area, driven by afternoon Delta winds.
"There's the wind that's inherent to this area," Marshall said. "But, the Delta breeze, as it gets later in the afternoon, it kicks up and that becomes problematic for us."
Marshall said the fire may have been sparked when an off-road vehicle caught fire.
Some welders working in the area rode the vehicle up a hillside to repair fences at a cattle ranch in the area, Marshall said.
They told fire inspectors that when they went to start the vehicle, it caught on fire, although Marshall said fire inspectors haven't been able to verify that account.
In addition to Contra Costa County crews, Marshall said Cal Fire responded to battle the blaze with a bulldozer, helicopter and four air tankers.
Fire officials said the blaze was 100 percent contained as of shortly before 3:30 p.m., with one minor injury reported.