A 12-inch diameter high-pressure natural gas main ruptured in a northeast Philadelphia neighborhood Tuesday night, killing one Philadelphia Gas Works (PGW) employee and critically injuring three others.

The explosion, which occurred in Philadelphia's Tacony neighborhood, is under investigation.

PGW CEO Thomas E. Knudsen and COO Craig White said in a joint statement their "worst fears were realized" on Tuesday "when we lost a member of the PGW family." The 19-year-old employee, they said, was responding to an "odor call" around 8:30 p.m. with a PGW crew and firefighters.

Three other PGW employees were critically injured in the blast and were being treated at Temple University Hospital's Burn Unit. Another PGW employee and a firefighter were treated and released.

PGW is owned by the city of Philadelphia and is the largest municipally operated gas utility in the country with about 6,000 miles of gas mains and service pipes that supply about 500,000 customers.

"The natural gas infrastructure around Torresdale Avenue [in Tacony] has been made safe and only a small number of customers are currently without service," said Knudsen and White. "We do not yet know the cause of the incident but we will continue to work with the Philadelphia fire marshal to investigate."

Before the fatal explosion, about 75 residents of the neighborhood living within a two-block radius of the gas main were evacuated to a temporary shelter after reports of a gas leak were reported. The blast occurred as PGW crews worked to fix the gas line.

Two houses and a utility truck were damaged in the three-alarm fire, which was under control by 11 p.m.

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