On January 22, 1999, while digging a trench behind a building at 406 Alabama Avenue, a backhoe operator damaged a 3/4-inch steel natural gas service line and a 1-inch water service line. This resulted in two leaks in the natural gas service line, which was operated at 35 psig. One leak occurred where the backhoe bucket had contacted and pulled the natural gas service line. The other was a physical separation of the gas service line at an underground joint near the meter, which was close to the building. Gas migrated into the building at 406 Alabama Avenue, where it ignited about 10:02 a.m. An explosion followed, destroying three buildings: 404, 406, and 408 Alabama Avenue. Other buildings within a two-block area of the explosion sustained significant damage. Three fatalities, five serious injuries, and one minor injury resulted from this accident.
The National Transportation Safety Board determines that the probable cause of the accident was the failure of R&B Construction to establish and follow safe procedures for excavation activities, resulting in damage to a 3/4-inch natural gas service line, and the failure of the Utilities Board of the City of Bridgeport to provide appropriate emergency response to the resulting natural gas leak.