A big rig rear-ended a tow truck early Wednesday morning on the eastbound 101 Freeway in Tarzana, jack-knifed and blocked lanes of traffic.
The crash occurred at Reseda Boulevard just after midnight, according to the California Highway Patrol.
The semi lost control and crashed into the tow truck, causing the big rig to jackknife and leak motor oil into lanes of traffic, the CHP said.
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The crash prompted the closure of the Nos. 1, 2, 3 and 4 eastbound lanes until further notice.
No injuries were immediately reported.