What Happened
What Happened
On November 6, 2024, about 3:09 p.m., a natural gas–fueled explosion fatally injured one person and destroyed a home in South Jordan, Utah. Several nearby residences were damaged, and families displaced. The South Jordan Fire Department responded, arriving on scene about 3:15 p.m. Technicians from Enbridge Inc. (Enbridge) subsidiary Enbridge Gas Utah, the natural gas service provider to the home, responded and arrived on scene about 3:45 p.m.2 Enbridge isolated the leak about 12:16 p.m. on November 7. At the time of the explosion, conditions were daylight and clear; the temperature was 41°F with no precipitation.
What We Found
What We Found
We determined the probable cause of the explosion was a through-wall crack that formed in the 1976 vintage 4-inch-diameter Aldyl A polyethylene gas distribution main from a rock impingement, allowing natural gas to leak, migrate about 150 feet, and accumulate in a home, where it was ignited by the home’s furnace. Contributing to the severity were insufficient safeguards to mitigate hazards presented by the leak.
What We Recommended
The events leading up to the home explosion in South Jordan illustrate how natural gas alarms could mitigate the consequences of gas leaks. Aldyl A piping manufactured before 1983 is prone to cracking and needs to be carefully assessed to protect public health and safety. Aldyl A pipeline failures are difficult to predict, and natural gas alarms can help safeguard members of the public who reside in areas with natural gas distribution systems. Natural gas alarms have been available for several years and can alert homes and businesses of gas leaks even when natural gas odorant is depleted in the natural gas. Natural gas alarms provide an early warning to building occupants before the gas concentrations reach an explosive level and alert occupants to evacuate the building. For more, see NTSB Safety Alert SA-098, Natural Gas Alarms Save Lives.
To address the threats identified during the investigation, Enbridge initiated several changes to their procedures and evaluation of Aldyl A pipe. Enbridge Gas Utah updated their risk assessment protocols for Aldyl A piping and completed leak surveys using an advance mobile leak detection system of 100% of the Aldyl A gas piping with the threat of cracking. All immediate leaks were evaluated and repaired. Enbridge has committed to an increase in its capital budget for risk-informed targeted replacement of high-risk Aldyl A piping. Their leak history, leak survey results, and repair data will be used to refine ongoing leak survey frequency and better inform asset replacement decisions.
To decrease the risk to the first responders and nearby residents and address the extended response time to locate the gas leak in South Jordan, Enbridge revised two standard practices specific to Enbridge Gas Utah operations for the investigation of leaks. One change refocused response resources on all gas assets in the area to improve the efficiency of the response and to isolate leaks as quickly as possible, and the other change requires bar hole testing of the perimeter of the structure and over all the gas assets in the area. To promote the installation of natural gas alarms, Enbridge has partnered with the American Red Cross in the Salt Lake City area and has made natural gas alarms/carbon monoxide detectors available at a recent event. In partnership with the city of South Jordan, Enbridge is also making additional natural gas alarms/carbon monoxide detectors available to residents at an upcoming event in May.
