A tractor-trailer fire closed four of five westbound lanes around 3:03 a.m. Friday on the Foothill (210) Freeway east of the Angeles Crest Highway in Altadena, the California Highway Patrol said.
It was unknown if the fire caused any injuries or fatalities, the CHP said.
Video from the scene shows what appears to be a large load of hay on the trailer ablaze with traffic backed up as firefighters work to extinguish the fire.
Los Angeles County Fire Department firefighters responded to the scene. Traffic proceeded through one lane as of 4:30 a.m.