The fire department was called out to the natural gas leak just before 5 a.m. Thursday, according to Phoenix Fire Capt. John Teefy, and crews arrived to find it already ablaze.
The fire downed power lines causing a power outage and damaged a homeowner's backyard fence, but firefighters controlled the blaze, according to officials.
The Salt River Project said five customers were affected by the outage but crews expected to restore power by 9:30 a.m.
Crews are unsure as to what caused the burning gas leak, Teefy said, but said the fire was helping firefighters and utility crews control the gas.
"Think of it like your backyard barbecue, " Teefy said. "The fire is on. All the propane or the natural gas is burning in that fire. If you turn off the fire while that burner is still on, the gas is going to spread out and then build up. That's when you actually have a hazard."
Southwest gas was still working to clamp the gas pipe as of 6:30 a.m.