LAFAYETTE -- Several people were injured but none of them seriously Sunday when a car swerved into traffic and caused a six-car crash Sunday morning, a California Highway Patrol officer said.

The crash occurred around 5:35 a.m. in the westbound direction just east of the Central Lafayette on-ramp, Officer James Evans said.

How the wreck unfolded was not clear immediately, but Evans said a car was in the far left lane, when it swerved and collided with at least one car, causing a chain reaction.

Television media reports that the driver swerved to avoid a cooler in the road and hit the center divide could not be confirmed.

It was not known immediately how many people suffered injuries, but initial reports by the CHP from the scene that one person was hospitalized with major injuries proved to be false, Evans said.

The wreck left at least four vehicles blocking all lanes of traffic, and the CHP issued a severe traffic alert at 6:14 a.m., advising people to avoid the area. The CHP opened the far right lane at 6:32 a.m., then opened all but the far left lane at 7:40 a.m. All lanes of traffic were open by 9 a.m.

That wreck was one of two that caused significant delays Sunday morning, Evans said. A three-vehicle wreck on westbound Interstate 80 on the Bay Bridge, just west of the Treasure Island off-ramp blocked the three right lanes, he said. That crash happened around 6:55 a.m., but nobody was reported to be injured seriously.

Heavy fog on the bridge may have been a contributing factor to the crash, Evans said, but CHP officers at the scene were continuing to investigate.

Check back for updates.

Contact Rick Hurd at 925-945-4789 and follow him at Twitter.com/3rdERH.