From the 2010 NFPA Fire & Life Safety Conference Blog

Two recent, high-profile incidents highlighted the practice of using flammable gas to purge or clean piping systems intended for industrial appliances. In both instances, the release of the gas to the atmosphere without specific controls allowed the gas to be ignited and produce fatal explosions. Denise Beach, a senior engineer at NFPA, talks about one of these incidents and the steps taken to amend NFPA 54, National Fuel Gas Code, to help prevent similar tragedies from occuring.