Around 7:45 a.m., a flatbed truck hit the parked tanker truck in the 500 block of Hoffman Boulevard, puncturing one of the tanks and causing it to leak diesel fuel, Richmond police spokeswoman Sgt. Nicole Abetkov said.
The driver of the flatbed truck and a passenger suffered cuts and other minor injuries, she said.
A Contra Costa County hazardous materials team and Richmond fire personnel were at the scene as of 8:45 a.m. working to clean up the spill, the sergeant said.
She said the cleanup is expected to take several hours.
A nearby off-ramp from eastbound Highway 580 to Harbor Boulevard was shut down as a result of the spill, and motorists are advised to avoid the area.