Five years ago a gas pipeline exploded in the Bay Area, killing eight people. The rupture created a fireball that destroyed a neighborhood in San Bruno, 12 miles south of San Francisco.

Federal investigations put the blame squarely on PG&E, exposing a pattern of negligence at both the utility and its state regulators.

I worked with reporter Rebecca Bowe to investigate whether the vast network of pipelines running under our feet is safer today.

We interviewed more than a dozen current and former California Public Utilities Commission staff to see how business was conducted during the years leading up to the blast, as well as currently. A lawsuit from the City of San Bruno also exposed more than 65,000 email threads between top regulators and utility executives. Using Overview we found communications revealing a cozy relationship that impacted decision making.

These interviews and records helped us uncover more data from investigations and public-records requests to better understand the concrete physical changes made after San Bruno, and the cultural changes at the utility and its regulator. I also analyzed more than a decade of data submitted to the Pipeline and Hazardous Materials Safety Administration to examine which upgrades PG&E was making to its system, and compare that to similar utilities.

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Listen to the two-part radio story:

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