HALF MOON BAY -- Several lanes of state Highway 92 near Half Moon Bay were blocked Monday morning by a jackknifed truck, according to the California Highway Patrol.

The crash was reported at 6:53 a.m. just west of state Highway 35, CHP Officer Marc Johnston said. A Sig-alert was issued at 7:06 a.m.

The truck was carrying coal, some of which spilled onto the roadway, Johnston said.

No other vehicles were involved in the crash, and no injuries were reported.

Johnston said around 7:40 a.m. that some westbound traffic was being allowed through but that eastbound lanes will remain blocked for several more hours.

Motorists were advised to use alternate routes.

A Sig-alert was issued around 6:30 a.m., and drivers are encouraged to take the Dumbarton Bridge or Bay Bridge as alternate routes.

There was no estimated time of opening.