Equitrans Midstream Corp. has updated the Pipeline and Hazardous Materials Safety Administration (PHMSA) on the root cause investigation and analysis related to the Rager Mountain Storage facility incident that took place last year, according to an Aug. 24 press release.

The incident, in which Rager well #2244 started leaking natural gas in November 2022, was caused by water- and oxygen-induced corrosion on the outside diameter of the top joint of the well, and the infiltration of organic and/or inorganic matter into the annulus, resulting in the well casing failing, according to the release.

Based on the results of an inventory verification test, the company’s initial gas loss estimate for well #2244 was approximately 1.29 Bcf. Following the root cause analysis, that number increased to 1.164 Bcf. The analysis indicates that approximately 1.037 Bcf was vented to the atmosphere, while the remaining 0.127 Bcf was diverted and contained within an underground formation.

It has been confirmed through extensive field and laboratory soil and water well testing that no gas migrated to nearby residential areas.

In an effort to mitigate this incident, the company says it has worked with a variety of third-party experts to ensure that all causes and/or contributors have been identified and addressed. The casing on well #2244 has been replaced, and the well has been plugged—whether this plugging will be permanent or temporary is to be determined at a later date.