Investigators are looking into why two of the eight Tesla did not burn as expected.

A big rig car-carrier loaded with eight Teslas caught fire on the Golden State (5) Freeway in Sylmar on Saturday, resulting in toxic smoke that shut down southbound lanes.

The fire was reported at 5:35 p.m. Saturday on the southbound Golden State Freeway just north of Balboa Boulevard, according to the California Highway Patrol.