The leak was reported to police at 2:18 p.m. when a landscape contractor nicked a gas line near the intersection of Sea View Parkway and Aughinbaugh Way, Alameda police Lt. Paul Rolleri said.
PG&E responded and advised that about 12 nearby homes be evacuated, Rolleri said.
The leak had not been capped and the residents were still being kept out of the homes as of 5:40 p.m., he said.
The intersection of Sea View Parkway and Aughinbaugh Way was closed to traffic, Rolleri said.
PG&E officials were not available this afternoon to provide information about the leak.