Firefighters are fighting a 20-acre brush fire near Old Ridge Route Route Road and Mesa View Drive near Quail Lake that started Saturday, officials said.

Both the Los Angeles County Fire Department and National Forest Service are responding to the brush fire, which started at 5:52 p.m., said county fire spokesman Rick Moreno.

The fire was at 30-percent containment at 9:40 p.m. with no active flames, and crews will work overnight to complete a line around the fire, said Angeles National Forest spokesman Nathan Judy.

“We’ll re-evaluate in the morning to see where we’re at containmentwise,” Judy said. “But we’re looking real good otherwise.”

According to Judy, about 300 personnel are fighting the fire.

In addition to Forest Service, the county responded with 12 engines, eight crews and several aircraft, including the Super Scooper planes loaned from Quebec, according to Moreno.

The Old Ridge Route Road was closed from Highway 138, Judy said.

No structures were threatened, and the cause is under investigation.