Source:  Josh Shaffer and Matt Ehlers, THE NEWS & OBSERVER, 2/5/10

The U.S. Chemical Safety Board has voted to urge changes to national fire codes to prevent more explosions like the blast that killed four workers at ConAgra's Slim Jim plant in Garner last year. Board Chairman John Bresland said the explosion happened while air was being purged from a new 120-foot length of natural-gas pipe. As part the procedure, workers fed pressurized gas into the pipe to clean out the air so they could light a new water heater. While workers purged the pipe of air, natural gas vented into a utility room off and on for more than two hours. Investigators determined this gas ignited, causing the explosion. The CSB, an independent federal agency, recommended that codes be changed to require that gas be vented outdoors. The board would permit indoor venting if workers are evacuated and local safety officials sign off first. Also, a combustible gas detector would be required rather than relying on workers' sense of smell. "This is what happened at ConAgra," Bresland said. "This is what we at the CSB do not want to happen again."