Susan M. Coughlin, then the acting chairwoman of the National Transportation Safety Board, urged UGI Corp. in a 1992 letter to begin replacing its cast-iron natural gas lines in the wake of an explosion that killed one person and injured nine in Allentown two years earlier, The Morning Call of Allentown reported.
UGI began replacing its riskiest pipelines in accordance with the NTSB's recommendations, a response the board deemed an "acceptable action." The company has replaced 120 miles of pipe since 1996, according to UGI spokesman Dan Adamo.
The explosion that prompted the NTSB recommendation happened about a mile from the scene of the Feb. 9 blast and fire that leveled homes and killed five people, including an elderly couple and a 4-month-old boy.
Investigators suspect a cracked piece of pipe is to blame for the explosion and fire that burned for hours as utility crews worked to cut off the gas supply in an area where the underground main lacked shut-off valves.
Coughlin recommended UGI replace pipes that could have been weakened by corrosion. The letter noted some of the cast-iron water and gas mains in Allentown dated to the late 1800s and early 1900s.
Information from: The Morning Call