The collision occurred around 3 a.m. near the Grand Avenue exit, the California Highway Patrol said.
Fuel and an unknown chemical, possibly up to 250 gallons, were reportedly leaking at the scene.
The cause of the wreck was not immediately known.
Some lanes began reopening around 6:15 a.m.
SIGALERT UPDATE: WB I-210 AT GRAND AVE, THE HOV, #1 AND #2 LANES WILL BE BLOCKED FOR AN UNKNOWN DURATION DUE TO A COLLISION— CHP PIO - LA County (@CHPsouthern) February 4, 2019