The tragic tale of a pipeline explosion that killed seven people and damaged nearly 60 homes was penned by Pacific Gas and Electric with help from remiss regulators, an investigation has found.

Deteriorating infrastructure, lax oversight, and non-existent emergency planning were among a “litany of failures” that contributed to the explosion, according to the recently released preliminary findings of a National Transportation Safety Board investigation.

“[The explosion is] the story of flawed pipe, flawed inspection and flawed emergency response,” NTSB Chair Deborah A.P. Hersman told the Los Angeles Times. “It was not a question of if the pipe would fail, but when.”

The explosion, which ripped through a San Bruno, Calif., subdivision last September, was caused when a weakened 1950s-era pipe under the neighborhood became flooded with gas from improperly opened valves. PG&E was unable to shut off fuel to the line, which eventually burst, releasing enough gas to power 12,000 homes for a year, according to the Times article.

Although moving, the story is far from original. Aging pipes and a dearth of inspectors leave most of nation’s 2 million miles of gas and oil pipeline at similar risk, as we reported in DR 553.

“In reality, there is a major pipeline incident every other day in this country,” Pipeline Safety Trust Executive Director Carl Weimer told the Associated Press. “Luckily, most of them don't happen in populated areas, but you still see too many failures to think something like this wasn't going to happen sooner or later.”