Mitchell Ow, a 28-year veteran assigned to the airport, was driving an Aircraft Rescue Fire Fighting rig when it rolled as he was turning near the Oakland Maintenance Center at 11:43 a.m. Tuesday, according to spokesman Sean Maher.
Ow, who was wearing his seat belt according to officials, wasn't thrown from the vehicle but authorities initially described the 55-year-old's injuries as life-threatening and said he was taken to a nearby hospital in critical condition.
No other injuries or property damage were reported.
The rig was loaded with 3,000 gallons of water and 420 gallons of foam when it flipped.
The airport remained open and its operations weren't impacted by the accident, Maher said.
The California Highway Patrol is investigating the incident.