PG&E had reduced the perimeter that needed to be evacuated when a private contractor employee ruptured a 2-inch diameter steel gas line around 1 p.m. today, Lt. John Dugan said.
Dugan said residents within a three-block radius of the house where the "significant" leak occurred were evacuated or would have been evacuated when they returned home.
Dugan estimated that 100 homes were affected. At 4:45 p.m., he said PG&E estimated it would take between six and 20 hours to repair the leak.
He said the wind was causing the natural gas to rise 12 feet in the air.
PG&E spokesman Denny Boyles said earlier this afternoon crews would squeeze the line shut to stop the leak until repairs are made.
Residents of the nine homes who need to find housing until the leak is fixed should call the Fairfield Fire Department at (707) 428-7300, Dugan said.