Allentown, Pennsylvania, Neighborhood Rocked by Deadly Gas Explosion

A natural gas explosion and fire in Allentown, Pa., claimed the lives of at least five people, including a 4-month-old child, and 79-year-old. Investigators say there are still two people missing.

Allentown Mayor Ed Pawlowski told reporters today, "This has been a very difficult, rough, 12 hour-period for the victims of this tragedy and their families. Their lives have been turned upside-down. Our thoughts, our prayers go out to the families affected by this horrible tragedy, especially the families of those who lost loved ones."

People who live in the area where the blast leveled two homes -- and damaged several others along a block of row houses -- describe the explosion as a thunderous roar that shook them from their beds and sent them running into the frigid streets. The raging inferno started around 10:45 p.m. Wednesday night and continued through early morning, as firefighters struggled to extinguish the flames. The weather also complicated things, as utility workers struggled to dig through ice and snow to shut down the ruptured gas line.

Big natural gas fires that are either sparked or fueled by a pipeline are often impossible to put out quickly, according to fire experts. The best way to attack a ruptured gas line the experts say, is to crimp off the fuel source, which can be a time-consuming process.

John Walsh, the president of UGI Utilities Inc., spoke at a news conference today along with the mayor, who was joined by the fire and police chiefs of Allentown. Walsh says a routine leak-detection check performed this week found no problems in the area of the explosion, and that there is no history of leaks for that section of gas main. Walsh continued, "there were no calls about gas odors before the explosion."

Allentown Fire Chief Robert Scheirer says the explosion is still being investigated. Fire investigators believe six other homes damaged by fire will most likely not be salvageable. Forty-seven properties in all were impacted by the blast, 10 of them businesses.

The Pennsylvania Public Utility Commission is also investigating. Agency spokeswoman Jennifer Kocher tells Fox News the utility has several inspectors on scene to determine the cause of the blast and to check for state or federal code violations, a process she says could take a long time.

The Allentown explosion is the third deadly natural gas line fire in the U.S. over the last few months. On January 18, a natural gas explosion in Northeast Philadelphia killed one gas company worker and injured five people, three of them critically. In the Northern California city of San Bruno, a natural gas line owned by PG&E Gas & Electric Co. exploded, killing 8 people, and destroying dozens of homes.

According to the National Fire Protection Association, natural gas causes an average of about 2,000 home structure fires every year. There are more than 210 natural gas pipeline systems in the country. Transmission pipelines stretching 305,000 miles through interstate and intrastate  pathways snake under the surface of the continental U.S.

Approximately 600 people were evacuated from the area of the blaze and are slowly being let back into the surrounding area as the investigation and search for more victims continues.