Several lanes were closed on the 5 Freeway in Castaic Wednesday morning while crews worked to clean fuel and oil that spilled from a jackknifed big rig.
It was unclear what the tanker struck, or if another vehicle was involved in the collision, according to the CHP site.
All northbound lanes were initially closed as diesel fuel and oil from the truck leaked onto the freeway, said Jennifer Cassidy of the CHP.
Vehicles were being directed to exit the freeway at Lake Hughes road, according to the CHP site.
It was unclear if there were any injuries in the incident.
All lanes had reopened by midday, Cassidy said.