LIVERMORE -- Fire crews worked to contain a large brush fire that shut down the westbound lanes on Interstate 580, according to the California Highway Patrol.

The fire was reported at 2:49 p.m. in the Altamont Pass east of Livermore, the CHP said, and smoke was so heavy that traffic had slowed to a mere 10 miles per hour.

Drivers experienced serious delays and the CHP had to divert traffic away from the flames as far back as Greenville Road.

It is unclear what started the fire and so far no injuries have been reported.

The fire was contained within the hour and all lanes have been re-opened.

Contact Katie Nelson at 925-945-4782 or follow her at Twitter.com/katienelson210.