HAYWARD, Calif. -- A small brush fire near westbound Interstate Highway 580 in unincorporated Hayward briefly caused a closure of a lane of the highway Saturday afternoon while emergency vehicles responded to the area, a California Highway Patrol officer said.

The fire was reported at about 12:30 p.m. in the area near Castro Valley Boulevard. It burned 2.1 acres before being controlled about 10 minutes after firefighters arrived on scene, Alameda County fire Battalion Chief Dan O'Hara said.

Fire trucks and other emergency vehicles blocked the far right westbound lane of Highway 580 near Five Canyons Parkway while crews fought the fire and mopped up hot spots, CHP Officer A. Paulson said.

Westbound traffic backed up on the highway until the lane was reopened shortly before 2:25 p.m. when fire crews finished mop up work and left the scene, Paulson said.

The cause of the fire was under investigation.