NOVATO (CBS SF) — Highway 121 near Sears Point was blocked Saturday afternoon in both directions, five hours after a big-rig hauling a tanker overturned, leaking fuel.

The semi-truck was headed north along 121, north of Highway 37, when witnesses told the CHP that it appeared to take a curve too tightly, hit a guardrail and flipped about 10:30 a.m., the CHP said.

The tanker was punctured and has leaked an unknown amount of fuel, the CHP said. It is not known if fuel had leaked into any waterways. Hazmat crews were called to the scene, the CHP said.

No injuries were reported in the crash.

As of 3:30 p.m., the highway was closed between Highway 37 and Cline Cellars and there was no estimated time for reopening.

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