Abstract: At approximately 4:30 p.m. on January 22, 1999, Employees #1, #2, and #3 were purging air from a newly installed 4-in. natural gas main in the mechanics shop boiler room. Residual natural gas remained in the 200-ft of existing piping and the air in the main pushed this residual gas into the boiler room where it dispersed to the ceiling and was ignited by an open flame. All employees suffered second-and-third-degree burns covering 7 to 41 percent of their bodies. Employee #1 died and Employees #2 and #3 were hospitalized. Injuries to three workers of the City of Elizabeth, who were also in the boiler room, were not recorded.