Crews on Monday were battling a two-alarm brush fire in Livermore that prompted the shutdown of westbound Interstate 580, according to fire officials and the California Highway Patrol.
The fire was spreading moderately and prompted the CHP to issue a Sig-alert for all westbound lanes of I-580 being blocked at Greenville Road.
The blaze had the potential to burn about 20 acres, fire officials said.
The Alameda County Fire Department, Livermore-Pleasanton Fire Department and Cal Fire responded to the scene.
No further details were immediately available.