On May 1, a Virginia section of the Mountain Valley Pipeline ruptured during water pressure testing.
An independent metallurgical test identified a defective weld as a cause of the failure. No internal or external corrosion was detected on the section, which was installed in 2018.
The report says the pipe failed above its maximum operating pressure of 1,480 pounds per square inch. The test was supposed to reach a pressure of 2,345 psi but fell 240 psi short of that.
The report identifies the breach as the only failure during hydrostatic testing of the entire 303-mile pipeline, which began carrying natural gas under high pressure in late June.
The incident rattled the community of Bent Mountain, Virginia, where landowners had been living with the pipeline’s construction for several years.
The pipeline’s builders and its state and federal regulators have insisted it operates safely.
MVP, which is owned by EQT, of Canonsburg, Pennsylvania, the largest gas producer in Appalachia, was fined $30,500 by the Virginia Department of Environmental Quality in July for erosion control and water pollution violations related to the May 1 incident and another on June 4.
On June 4, a connecting hose broke at the end of a water pressure test in Montgomery County, Virginia. It was unrelated to the May 1 failure and didn’t involve the main part of the pipeline.
Construction on the MVP had stalled for years due to court challenges until West Virginia Sen. Joe Manchin attached a requirement to a spending bill last year for its completion.
The nearly $8 billion pipeline was intended to serve markets in the mid-Atlantic and Southeast.