An early morning chain reaction crash in the westbound lanes of the Bay Bridge early Friday, forcing the closure of two lanes and triggering a massive traffic backup for the  morning commute.

According to the California Highway Patrol, a collision involving several vehicles took place at around 5:30 a.m. in the westbound lanes of the Bay Bridge near Treasure Island.

Two lanes of the busy traffic artery were blocked for about 30 minutes and all lanes were shut down for about 15 minutes as the damaged vehicles were removed from the bridge.

Authorities said there were minor injuries in the crash but further details were not immediately available.

Two compound the woes of commuters on westbound Highway 80; a big rig was also involved in a collision that blocked the right and center lanes near Powell Street in Emeryville leading to the bridge.

The CHP advised morning commuters to allow for extra time while heading into San Francisco from the East Bay.