On May 16, 2007 an explosion occurred in a residential neighborhood located in the Nashville Tennessee area. The explosion and subsequent fire caused extensive damage to one residential structure and severe injury to the owner. The damage to the structure is shown in figure 1.
Figure 1
Because of the way the fire burned, the suspected cause was a natural gas leak. In addition to the residential structure, the grassy area in the front yard was also ignited and continued to burn as if fed from underground. The local gas company was later asked to excavate and expose the gas main and service line.
It was later discovered that a cracked valve flange had been leaking natural gas. The cracked valve flange is shown if figure 2. Based on information received at the scene, the valve was approximately 20 years old. Because of the age of the valve, the following question arose: " How many more valves with cracked bodies or flanges are out there?"
Figure 2
During the investigation and specifically, the testing and excavation of the gas line, television news crews were on the scene for the first two days. Because of the potential for the filing of lawsuits, no public statements were made by any of the investigators. It is now three years later and all lawsuits have been resolved. To date, the public still does not know what happened. More importantly, the public is most likely not aware of the 1991 alert issued by the National Transportation Safety Board stating that "natural gas operators should have a program to identify and replace cast iron systems that threaten public safety". Furthermore, the public is most likely not aware of the fact that the local gas company spent 15 years and 62 million dollars in an effort to replace all cast iron and bare steel pipe. Lastly, the public is not aware, for whatever reason, the cast iron valve in this incident was overlooked by the gas company. As a result, an explosion and fire occurred. The very thing that the alert and the replacement effort was ssupposed to prevent.
This case was the focus of an "iteam" investigation" conducted by WSMV TV. Please go to the main navigation menu and press the button labeled "WSMV iteam report" to read their story and see the video.
