PITTSBURG -- Two people were hospitalized with minor injuries after a big rig was involved in a collision with at least two other cars on westbound Highway 4 on Monday morning, the California Highway Patrol said.

The wreck, which happened at 6:02 a.m. just west of the Bailey Road exit, created a mess that forced the closure of three lanes and severe traffic alert in the area until 7:20 a.m., CHP Officer James Evans said. It was taking at least an hour for commuters to make their way from Antioch to Concord, according to the CHP.

One person was thrown from a vehicle but was up and walking around at the scene, Evans said. That person, and another who was complaining of pain, were taken by ambulance to Kaiser Permanente Medical Center in Antioch as a precaution, Evans said.

Investigators were determining how the crash occurred, Evans said. The CHP closed the far right three lanes while waiting for a tow truck to remove three vehicles involved in the crash, he said. Check back for updates.

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