Officers responded to a crash on the Bay Bridge involving four vehicles at about 6:15 a.m., CHP Officer Peter Van Eckhardt said.
Various lanes were closed to traffic as emergency crews responded and vehicles involved were cleared from the roadway, Peter Van Eckhardt said.
Four people were reportedly injured in the collision, Van Eckhardt said, one of whom has been taken to a hospital for treatment.
A Sig-alert was issued at about 6:20 a.m. and canceled at 6:40 a.m.
Traffic on westbound Highway 80 heading into San Francisco remains heavily backed up at 7 a.m., Van Eckhardt said.