The first accident happened at 99 and Bethel.
A second, smaller crash then occurred at 99 and Kamm, moments later the largest pileup happened at 99 and Sierra.
The CHP is still trying to determine exactly how the accident happened.
This was the scene of the largest wreck.
Five big rigs crashed on this part of south bound 99 with five other vehicles.
Some people were trapped in their cars.
Others had to make quick decisions to save their life.
Samuel Ramirez: "I'm lucky I'm still alive. The engine is crammed up in the truck as you can see. It's crazy."
Samuel Ramirez drove this truck packed with paint buckets.
His load exploded when the accident happened covering him with paint.
Ramirez: "It was pretty intense. It was like you couldn't really think you just had to act. You gotta think just move out of the way just make sure you try not to hit anyone else."
Traffic came to a standstill as car after car crashed into each other.
Commuters say the thick fog blinded them.
This woman's car skidded into the back of a big rig.
She was trapped more than an hour.
Rescuers used the powerful Jaws of Life to rip apart her car and extract her.
The unidentified woman suffered minor injuries and was transported to the hospital.
Michael Bowman, Cal Fire: "It's really a team work effect with as and the victim inside. We wish we could get them out in minutes but sometimes it doesn't work that way and we have to take our time to get them out safely."
Chaos spread across a large part of Highway 99.
The CHP said they were pacing cars at the time but people drove too fast in fog that was very thick and moved in quickly.
Paul Solozaro, Highway Patrol: "At 8:55 Tuesday morning, they said visibility was a thousand feet. So sometime in between there the fog just came and sunk in."
The CHP reports seven people taken to the hospital.
Two of them reported in critical condition, and they are being still being treated.
So far no citations have been issued.