Traffic was snarled in both directions as the California Highway Patrol shut down lanes after the crash was reported around 5:30 p.m.
Authorities didn't allow any vehicles within a half-mile from the scene as firefighters extinguished the flames with foam. It's unclear what type of chemical the truck was hauling.
It was not immediately clear what caused the incident or if any injuries were reported.
Northbound lanes reopened after several hours, but only one lane on the southbound side was open Monday night.