PG&E only inspected the nearly 100-year-old tower suspected of sparking the massive Camp Fire by air in the decade leading up to the disaster, records reviewed by NBC Bay Area’s Investigative Unit show.
"If they haven’t gone up the tower in a decade, that’s wrong," said State Sen. Jerry Hill (D-San Mateo) about what NBC Bay Area’s Investigative Unit found in reviewing the inspection history of the Caribou-Palermo line detailed in a report recently submitted to a federal court judge. "It doesn’t give you the clear, concise picture that’s necessary."
In the inspection history for the line, PG&E lists more than two dozen aerial patrols and inspections of the rugged Butte County terrain where a hook that holds up high-voltage power lines failed, and the Camp fire started. But all those inspections failed to find any problem with the worn hook that snapped, leaving electrified lines dangling.
The accounting was drafted for U.S. Judge William Alsup, who is now considering new restrictions on PG&E’s five year probation stemming from the San Bruno gas line explosion in 2010, in light of the recent firestorms.
State Senator Hill says it is his conclusion that aerial checks do not provide "enough information to determine the structural integrity, the corrosion of the tower or the fittings that are holding things together."
NBC Bay Area has learned that while PG&E requires its highest voltage transmission towers – carrying 500,000 volts – be climbed from three to 12 years, lower voltage towers like the 115,000 volt capacity Caribou-Palermo circuit only have to be climbed if warranted, like to check for damage from a major storm. Such a storm hit the remote area back in 2012, causing five towers not far from the fire’s origin to collapse. The structures were replaced in 2016.
For 115,000 volt circuits, PG&E requires a "detailed evaluation" every five years, which, under the company's standards involves: "visual observation; use of measuring devices, tools, or routine diagnostic tests” with “the ability to view all sides of the facilities."
Although PG&E told Alsup it "typically" relies on ground inspection crews, its records for Tower No. 27/222 show it was checked from "overhead" in 2014. That was the last time the company carried out a five-year mandated “detailed” inspection of the transmission line before the fire.
Under PG&E standards in effect in 2016, such detailed 5-year mandated transmission inspections can only be done by air if an exception is granted by a maintenance superintendent based on limited ground access. Even if ground conditions are an obstacle, the rules say, detailed air inspections cannot be done back-to-back to vouch for transmission towers.
It is not clear when the last time was that somebody actually climbed the tower tied to the fire, however. And the accounting to the judge does not specify how the tower or line was inspected during the 5-year inspection done in 2009.
In that inspection, the company identified so-called "three-bolt" connectors, which clamp separate pieces of wire together at the tower, as needing replacement. That work was finally done in 2016, according to the company summary. PG&E stressed the three-bolt clamp connectors were distinct from the connector hook that failed before the Camp fire.
"They didn’t find anything," said attorney Dario de Ghetaldi, an attorney for wildfire victims who reviewed the inspection history provided by the utility.
"If they can’t find a problem like this, in looking at this tower over 20 times over a ten year period -- if they can’t find that problem, this gives me no confidence about the rest of their transmission system."
In a statement, PG&E says it relies on "routine patrols, detailed inspections, testing, repairs and replacements – all designed to comply with state and federal regulatory requirements and to identify and address safety and reliability issues."
State regulators say it is left up to the utility to figure out the best way to inspect its transmission equipment.
"It is the onus of the utility to determine whether or not they can effectively inspect transmission lines via aerial methods as opposed to ground-based methods," the state Public Utilities Commission said in a statement.
Hill says the lesson of the Camp fire is that aerial inspections alone just don’t suffice.
"If you are going to rely on the integrity of that infrastructure," he says, "and if you are going to put people’s lives at risk by not doing it properly… that’s what may have happened in this case."