The accident was reported at 6:53 a.m. just east of Pilarcitos Creek Road when the tractor-trailer struck the highway's center divide and punctured its tank, said CHP Officer Grace Castillo.
Both eastbound lanes of the highway were temporarily blocked and a Sig-alert was issued shortly after 7 a.m.
There is no estimated time for when the No. 1 eastbound lane will reopen.
In addition to the CHP, the California Department of Transportation and the state Department of Fish and Game have responded to the crash site.
No one was injured in the crash, Castillo said.