Flames swept through about 40 acres of vegetation in the east foothills of Santa Clara County on Tuesday morning, a blaze that was sparked by a vehicle fire, according to the Cal Fire.

Firefighters believe the brush fire was sparked at about 5:30 a.m. when an abandoned vehicle on Mt. Hamilton Road near Quimby Road went up in flames. Two abandoned vehicles were found about 2 miles east of the Grant County Park entrance, according to CHP Officer Chris Falkowski.

At 1:40 p.m., the fire was 100 percent controlled but not extinguished, according to Pam Temmermand, a fire prevention specialist at Cal Fire.¿

"We have a control line all the way around it, but it's not out," she said. "There are still spots burning within the line."

She said the fire was in an area of heavy brush and grass. No structures were threatened, and no injuries reported. She did not have an expected time when the fire would be extinguished, but added that crews were expected to remain at the scene well into the night.

One vehicle was on fire and there was no evidence of a collision. The cause of the fire is under investigation.

Cal Fire, along with the San Jose and Spring Valley fire departments, battled the blaze, according to San Jose fire Capt. Mike Van Elgort.

Temmermand said that at its peak, about 75 firefighters were involved.

San Jose fire crews sent four engines and three water tenders, which are portable water tanks capable of carrying hundreds of gallons of water. Van Elgort described the blaze as a "small, slow-moving fire."

Staff writer Robert Salonga contributed to this report. Contact Mark Gomez at 408-920-5869. Follow him at Twitter@MarkMgomez.