CHP Officer Saul Gomez acknowledged that the freeway could be shut down for days, saying "this is going to go on for quite some time."
The blaze started on the eastbound 60 Freeway near Paramount Boulevard shortly after noon and the cause is currently unclear, said CHP Officer Saul Gomez.
"We don't know what caused this thing to spark up, but we can tell you that this is an extremely dangerous situation," Gomez said.
"With these big rigs, anything can happen," Gomez said. "Many times what we've seen is that they usually spark up from a brake problem, an electrical problem. It could be a myriad of things. At the moment we don't have that information though."
By 2 p.m., the fire appeared to be mostly under control, although the unidentified combustible material inside the truck continued to spark flare-ups. Authorities are unsure what the vehicle was transporting because the delivery paperwork was destroyed in the fire, said Gomez.
The vehicle's driver and a passenger were able to escape safely, said CHP Officer Vince Ramirez.
Both the 60 eastbound and westbound lanes are closed and drivers were being re-routed around the area.
Gomez recommended drivers avoid the 60 and use the 10 Freeway as an alternate route.
"It'll remain this way until we get guidance from the fire department that we can get people back on the freeway," said Ramirez.
Aerial video showed large plums of black smoke visible for miles as traffic was snarled in the area.
"I can see all the traffic as result of the closure -- it's bumper-to-bumper where it's normally moving at a brisk," said Alberto Pimentel, president at nearby Don Bosco Technical Institute. "I'll be staying here for lunch."
The tanker truck was still moving on the freeway while on fire, Gomez said. It finally came to rest near an overpass, which officials are inspecting.
"The bridge appears to have some severe damage to it," Gomez said. "That's still to be determined."
No other vehicles were involved in the fire, Ramirez said.