A PG&E gas line that ruptured while crews were working on the line on Thursday has disrupted traffic in East Palo Alto and blocked access to U.S. Highway 101.

The rupture, which occurred at University Avenue and Donohoe Street, began at about 10:53 a.m., causing a significant hissing of leaking gas. The roads were opened during the peak commute. The area is still under construction, however, and some lanes on Donohoe are restricted.

PG&E spokesperson Mayra Tostado said a third-party contractor, not affiliated with PG&E, struck a 4-inch plastic gas line while digging at the intersection.

"After the contractor hit the gas line, a leak was reported due to the line being damaged during the incident, and local first responders responded to assist PG&E in making the area safe. PG&E crews were able to safely stop the flow of gas at 2:17 p.m. and remain on the scene working on repairs. Gas service to the area is not impacted," she said in an email.

Eastbound traffic on University Avenue was diverted onto northbound Highway 101. Westbound traffic on University was diverted onto Bell Street to Euclid Avenue. From there, drivers were directed to northbound Highway 101 at the freeway entrance where East Bayshore Road transitions to Donohoe Street, police said. Traffic was backed up on Bell Street and Euclid Avenue on Thursday afternoon.

The rupture didn't cause evacuations except from the Chevron gas station at the corner, police said.

Tostado said the incident is under investigation. It "serves as an important reminder for contractors and homeowners to always dig safely and call 811 to have professional locators mark underground utility lines for free prior to starting any digging project, big or small," she said.