CUPERTINO -- For the first time, a controversial DC-10 converted into a fire-fighting air tanker swooped low over the Bay Area hills to battle a wildfire above Cupertino near the Stevens Creek Reservoir.

The tanker has been the focus of debate since it was damaged on June 25 when as it prepared to drop fire retardant along a Kern County ridge a severe downdraft forced the aircraft to sink and its left wing clipped several treetops. It was repaired and grounded until late July and returned to duty only after its crew received further training and a change was made in how its runs were made.

State officials say its use is safe, but federal officials still have refused to approve its use. There has also been a debate over its steep pricetag. But on Thursday, the giant tanker did it's job -- helping firefighters wrestle control of the 150-acre blaze.

It was the first time the DC-10 had been used to battle a Bay Area fire.

On Friday, officials said the blaze near Stevens Creek Canyon was 50 percent contained with 100 containment expected by 8 p.m.

The blaze was burning in the foothills of the Santa Cruz Mountains. Two firefighters have been treated for injuries; one had heat exhaustion and the other had a miscellaneous injury. Both were in stable condition.

The fire forced the overnight closures of nearby Montebello Road and also for Stevens Canyon Road.

People living in about 25 residences voluntarily evacuated and the staff of Camp Costanoan also agreed to evacuate.

The fire started around 11:45 a.m. between state Highway 35 and Stevens Creek Reservoir.

Crews discovered downed power lines near the fire's origin, but the cause of the flames remains under investigation.