Two Santa Maria women were killed and two other people were seriously injured Saturday afternoon in a head-on crash on Highway 154 in Los Olivos.

The collision, involving a Ford F-150 pickup, a Toyota sedan and a third vehicle, occurred at about 1:30 p.m. on Highway 154, just west of Foxen Canyon Road, according to the California Highway Patrol.

The Santa Maria women — the 64-year-old driver and a 58-year-old passenger — were declared dead at the scene, said Paul Christensen, a Santa Barbara County Fire Department spokesman.

Their names were not released pending notification of relatives.

The Toyota was eastbound on Highway 154 and, for unknown reasons, crossed over into the opposing lane and slammed into the westbound pickup, the CHP said.

The Toyota caught fire after the crash, and at least one of the victims was trapped in the wreckage, Christensen said.

The 46-year-old driver of the pickup and his passenger, a 45-year-old woman, both of Reseda, suffered major injuries were transported to Santa Barbara Cottage Hospital, the CHP said.

Details on their conditions were not available.

The third vehicle, a Ford Fusion, was westbound behind the pickup, and ran off the roadway to avoid the collision, striking a tree, the CHP said. That driver, a 44-year-old Nipomo man, was uninjured.

Highway 154 was shut down in both directions after the wreck, but reopened shortly after 3 p.m., the CHP said.

Noozhawk executive editor Tom Bolton can be reached at Follow Noozhawk on Twitter: @noozhawk, @NoozhawkNews and @NoozhawkBiz. Connect with Noozhawk on Facebook.