Gas drifted across a major highway in San Mateo County, prompting the California Highway Patrol to close the roadway during rush hour traffic Monday.

Both directions of Highway 92 were closed at Highway 35 for nearly an hour, according to the CHP. Half Moon Bay police and PG&E officials also responded.

A gas main broke in the area around of 4:30 p.m. Monday afternoon. The highway was closed by because of reports of “natural gas drifting across the roadway.”

The highway reopened around 5:40 p.m. because the source of the leak was capped.

The cause of the gas main break is not known.

akoskey@sfexaminer.com