The brush fire at Camp Pendleton that has burned 2,500 acres is now 41% contained, Marine officials said Monday.
Full containment is expected by Tuesday, officials said.
The fire is being battled by 339 firefighters from the Camp Pendleton Fire Department, the U.S. Forest Service and other agencies, assisted by five helicopters.
As they make more progress, fire officials plan to release firefighters and equipment no longer needed.
The fire started about 12:45 p.m. Saturday in the Lake O'Neill area of the sprawling base.
Minor damage was reported to four buildings on the base. A truck parked near the hospital was destroyed. No injuries have been reported. The cause of the blaze has not been announced.
On Saturday, the O'Neill Heights housing area and the base hospital were evacuated. Residents have now been allowed to return and the hospital has reopened.
Patients at the 61-bed hospital had been transferred to Tri-City Medical Center in Oceanside and Naval Medical Center San Diego after a power outage at the facility 12 miles from the main gate of the base.