Firefighters from the Contra Costa County Fire Protection District and California Highway Patrol officers were called to the scene in the westbound lanes of the highway near Somersville Road at 1:24 p.m., according to fire dispatch records.
Six ambulances were called to the scene.
CHP spokesman Officer Dan Gilmore said the injuries were all minor.
The crash remains under investigation, he said.
Westbound lanes were reopened after being closed for a short time.