The San Bruno Pipeline Rupture and Fire
At about 6:11 p.m. on 9 September 2010, Pacific Gas and Electric's 30-inch Line 132 ruptured beneath San Bruno's Crestmoor neighborhood. Escaping natural gas ignited, killing eight people, destroying 38 homes, and damaging 70. The NTSB traced the failure to a defective 1956 welded pipe section, inadequate quality control and integrity management, and regulatory gaps that left the flaw undetected.
What existed before
Line 132 had been relocated in 1956 using a short pipe assembly made from pieces with substandard welds. PG&E's records incorrectly characterized parts of the line, and the company's integrity program did not identify or remove the defective section. Older pipelines were also exempted from a pressure-test requirement that might have exposed it.
Trigger and cause
Electrical work at PG&E's Milpitas Terminal caused pressure changes in the transmission system. A visible seam-weld flaw that had grown over time reached critical size. The pipe burst at Earl and Glenview, released an estimated 47.6 million standard cubic feet of gas, and excavated a large crater before the gas ignited.
Aftermath
Fire engulfed the neighborhood and damaged the local water system. Responders evacuated hundreds of homes and used ground crews and aircraft to limit spread. The line lacked automatic or remote-control shutoff valves, and delays in identifying and isolating the rupture allowed gas to feed the fire.
Why it matters
The rupture began with defects buried for more than half a century, but its severity was shaped by contemporary records, regulation, monitoring, valve design, and emergency decisions. The location makes the cost of weak infrastructure governance visible at the scale of a residential block.
Uncertainty note
Early reports gave different counts for destroyed and damaged houses and a slightly different pipeline mile point. This file follows the NTSB final report: 38 destroyed, 70 damaged, and mile point 39.28. The coordinate marks the final-report intersection.