Fresno Fire Department Spokesman Koby Johns said there was a real risk. "The biggest threat is explosion."
Construction crews working in the basement of the old Gottschalks department store knocked down a block wall, which fell on the gas line causing it to break, and spew gas into the basement.
Johns added, "There's very high concentrations of gas inside the old Gottschalk's building."
PG&E Spokesman Denny Boyles said utility crews had a tough time turning it off. "That's one of the realities we are in Downtown Fresno the infrastructure is a little bit older this building in particular is a little bit older so you are not dealing with the most modern line."
While crews worked, a two block area around the building, a section of the Fulton Mall, was shut down, electricity was shut off and the neighboring Californian Hotel was evacuated, forcing residents out onto the street. When they were allowed back in the power was still off and the elevators were not running.
"It's a lot of inconvenience. Powers out, our rooms are hot," said resident Rita Patton. "I live on the 8th floor on the Inyo side so I get no air in and of course our refrigerators are off."
Joy Short, a hotel visitor told ABC30, "I went up 40 flights of stairs to get my medicine."
Despite the hassles residents praised firefighters and the hotel staff.
Once the gas was shut off, giant fans were brought in to blow the gas out of the basement.
No injuries were reported, and the danger was over by late afternoon.