Police say it happened around 5 a.m. just before San Pablo Dam Road.
Police said in an alert at 5:52 a.m. that traffic backups are expected for several hours.
MORE: Fatal pedestrian crash on SB I-680 in Walnut Creek Thursday morning, CHP says
The California Highway Patrol is clearing the scene.
One car was flipped on its roof and the driver was killed, authorities said.
Multiple cars were involved.
It's unclear if anyone else was hurt in the incident.
Bay City News contributed to this report
If you're on the ABC7 News app, click here to watch live