UPDATE (Feb. 1, 2017, 7:36 a.m.): According to California Highway Patrol public information officer Robert Rodriguez, the southbound lanes on Highway 43 are blocked.

The 15 people were not all involved in the crash, but some of them have stopped to check on the people involved in the head-on collision.

One person who complained of pain has refused medical attention.

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According to California Highway Patrol, a head-on collision on Highway 43 at Panama Lane is causing major traffic delays.

Approximately 15 subjects are involved, but it is unclear if there are any injuries at this point. It is also unclear how many vehicles are involved.

This story is developing.