The fatal explosion occurred May 23 at an apartment building in the Oak Cliff neighborhood near the Dallas Zoo. Among the three fatalities was one child.
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A natural gas line linked to a fatal May 28 explosion was not marked in advance of the blast that leveled a Dallas apartment building.
That was the initial conclusion of the National Transportation Safety Board, the federal agency charged with reviewing such mishaps, in a preliminary report. Three people died in the explosion and subsequent fire. Six others were injured. The initial NTSB report was released on July 1. Atmos Energy faces litigation as a result of the blast.
According to the NTSB, a third-party contractor was conducting soil sampling near the apartment prior to the explosion. The contractor, identified as Engineering and Consulting Services Southwest, had submitted a Texas 811 excavation notification seven days before the incident, according to published reports.
The NTSB in its preliminary report stated that some underground utilities had been identified using paint and flags before drilling began. However, the location of a natural gas line apparently involved in the accident had not been identified and marked. The NTSB did not indicate why the line was unmarked, nor has it yet assigned responsibility.
The fatal explosion occurred May 23 at an apartment building in the Oak Cliff neighborhood near the Dallas Zoo. Dallas Fire-Rescue Assistant Fire Chief James Russ has said that DFR crews had responded to a reported gas leak at the apartment complex prior to the explosion, and that more than 70 units and 120 firefighters responded afterward.
In its preliminary report, the NTSB said the distribution system serving the area included a 4-inch polyethylene natural gas main operating beneath its maximum operating pressure. NTSB also reported the existence of a polyethylene service line connecting to the apartment building and an even narrower section of that service line leading to the building’s gas meter. Both the 4-inch gas main and the smaller section of the service line were installed in 1988, according to the NTSB.
“Although the locations of some of the assets had been marked by painting and flagging, the location of this gas line had not been identified and marked,” the NTSB stated.
The agency also noted that “All aspects of the accident remain under investigation while the National Transportation Safety Board determines the probable cause with the intent to issue safety recommendations to prevent similar events.”
Parties participating in the investigation include the Pipeline and Hazardous Materials Safety Administration, the Railroad Commission of Texas, Dallas Fire-Rescue, Atmos Energy, Environmental Consulting Services Ltd. and United States Infrastructure Corporation, according to reports.