Mandatory evacuations are underway Monday evening on Somerset Drive, Somerset Place and Hampshire Way in Novato because of a gas leak, police said.
At 4:59 p.m., police, firefighters and PG&E were working to evacuate residents and stop the leak at San Marin and Somerset drives.
Police said the leak may be contained as early as 7 p.m. and as late as 9 p.m.
Gas has been turned off to homes near Somerset Place, Somerset Drive and Hampshire Way.
Police said no evacuation centers have been established. Police are providing updates on their social media sites.