Overview:

At 6:11 p.m. PDT on September 9, 2010, a 30-inch diameter natural gas transmission pipeline ruptured in the Crestmoor neighborhood of San Bruno, California. The resulting explosion and fire destroyed 38 homes, damaged 70 more, caused eight fatalities, and injured many others.

Key Findings:

• The pipeline rupture was due to a defective seam weld in a pipe segment installed in 1956.

• Records inaccurately classified the pipeline segment, leading to inadequate testing and inspection.

• The California Public Utilities Commission’s (CPUC) oversight was insufficient to detect and correct deficiencies.

Lessons Learned:

• Accurate Record-Keeping: Utilities must maintain precise and comprehensive records of pipeline specifications to ensure appropriate inspection and testing.

• Rigorous Inspection Protocols: Regular and thorough inspections, including pressure testing and weld assessments, are vital for pipeline safety.

• Regulatory Oversight: Regulatory bodies need to enforce stringent oversight and ensure compliance with safety standards.