A manufacturing defect, a degraded coating and an ineffective corrosion prevention system contributed to a fatal explosion and fire on Enbridge Inc.’s Texas Eastern Transmission (Tetco) natural gas pipeline near Danville, KY, the National Transportation Safety Board (NTSB) said last week.

The August 2019 Tetco Line 15 rupture and subsequent fire caused one death and sent six people to the hospital. NTSB noted the incident burned about 30 acres of land, destroyed five homes and damaged 14 other residences. The accident also raised market concerns about potential limits on Appalachian Basin gas flows reaching the Gulf Coast.

Investigators concluded “that the combination of a pre-existing manufacturing defect – known as a hard spot – together with a degraded pipeline...