Refuting earlier reports, Mayor Michael Nutter on Tuesday claimed a gas leak may not be to blame for an explosion Monday that leveled three homes on the 400 block of Daly Street in the Whitman section of South Philadelphia.
"We don't know that it was a gas leak or not," he said.
"The Fire Marshal will tell us that."
The information came despite a release from the city Monday that stated officials "determined that an explosion occurred due to natural gas" and that the Fire Marshal, Department of Licenses and Inspections and Philadelphia Gas Works were "investigating the cause of the gas leak."
Nutter also addressed reports the explosion occurred in the basement of 428 Daly St. and was possibly related to a recently installed hot water heater.
He said he did not know where the worker was during the blast and noted all permitted work on the property, including the furnace installation, was fully completed and inspected last Friday.
He further stated the only repairs still being performed Monday were considered cosmetic in nature.
"It is our best understanding the individual who was injured was doing other work inside the house, possibly described as more of a tile person," Nutter said.
"He was doing some floor work that does not require a permit."
Councilman Mark Squilla said Tuesday neighbors in the area told him they overheard the injured worker say immediately after the blast he had been lighting a cigarette at the time.
"This is just something I heard from the community that they overheard from the person who was injured," he said.
Nutter called the rumor "pure speculation at this point" and refused to comment further, pending an investigation by the Fire Marshal's Office.
Squilla agreed more information will be forthcoming following the inquiry.
"The Fire Department was on the scene today trying to find origin of explosion, whether it was in the basement where the water heater was," he said.
"From what I understand, they actually pulled the water heater out of rubble today, so if it was intact, maybe it wasn't the water heater that caused the explosion."
Nutter said following the investigation, L&I will award a contract to complete the full demolition of the three properties that collapsed during the explosion.