The fire was burning in a very remote part of the island on the south end, near the western span of the Bay Bridge, close to the Yerba Buena tunnel.
San Francisco fire trucks had a tough time accessing this blaze. So they let both of the department's fire boats battle the blaze from the bay.
The fire department closed the two right lanes on the lower deck of the bridge and set up hoses to hit the fire from the bridge. Though all eastbound lanes have reopened, it's still heavily impacting traffic.
The westbound Treasure Island off-ramp remains closed.
The fire burned grass and brush. No structures were damaged and no injuries were reported.
Watch ABC7 News at 11 p.m. for the latest on this developing story.