An overturned tanker carrying thousands of gallons of diesel fuel forced a full closure on the northbound 5 Freeway Wednesday morning near the eastern end of Griffith Park.
The crash and fuel spill were reported near Glendale Boulevard. A hazardous materials crew is at the scene.
The double-tanker's capacity was estimated at about 9,000 gallons, but it was carrying 7,500 gallons, according to the fire department. It was not immediately clear how much spilled onto the freeway.
"This will be an extended duration operation," the LAFD said in a statement.
The freeway and nearby roads through Elysian Park are used by baseball fans to get to and from Dodger Stadium, where the Dodgers host the Cardinals Wednesday at noon.
Details about the cause of the single-vehicle crash were not immediately available. No injuries were reported.
Crews were still mopping up the mess well into the afternoon commute, with lanes still shut down at 4 p.m.