David Mazaika, who has been with the Moraga-Orinda Fire District for 7.5 years, was part of a crew working on the fire district's annual fire trail maintenance program.
Each year, the district inspects fire trails and contracts with a grading service to skim the surface of the trails to make sure they are safe for fire season, Mentink said.
Mazaika, 33, was driving the lead vehicle, which goes ahead of the grader to check for obstructions or other safety issues, when shortly before 10 a.m., his vehicle left the fire trail and rolled 150 to 200 feet down an embankment.
Other firefighters from the district responded to the scene and freed Mazaika, who was trapped inside the vehicle, Mentink said.
Once he was freed, firefighters used a series of ropes and pulleys to hoist him up the hill to an ambulance, which took him to John Muir Medical Center in Walnut Creek.
The cause of the accident is still under investigation.
Personnel from the Moraga-Orinda Fire District, East Bay Regional Park District, East Bay Municipal Utility District and a medical helicopter responded to the scene.