Profit pressures and untrained staff allowed a century-old C hook to fail, causing the deadliest and most destructive wildfire in California history, according to a report released by the Butte County district attorney Tuesday.

The 92-page report and accompanying video detailed the evidence that convinced Pacific Gas and Electric to plead guilty to involuntary manslaughter for causing the 2018 Camp Fire that killed 84 and destroyed 18,800 structures. (See PG&E Pleads Guilty to 84 Homicides and Arson.)

The fire began at 6:15 a.m. on Nov. 8, 2018, when the iron C hook holding the insulator on transposition tower 27/222 on the Caribou-Palermo 115-kV transmission line failed, causing the jumper conductor to fall onto the steel tower. The resulting electric arcs rained molten steel and aluminum, which sparked the grass and brush below.

Within an hour, the fire had reached the town of Concow; 30 minutes later it engulfed Paradise, seven miles away. It took 17 days to contain the blaze, which would consume 153,336 acres.

Circa 1921

The Caribou-Palermo line was built between 1919 and 1921 by the Great Western Power Co. to deliver power from the Caribou Powerhouse hydro project to the Valona Substation in Contra Costa County. PG&E acquired the assets when it purchased Great Western in 1930.

PG&E has long recognized wind as one of the top causes of structure failure on transmission and distribution lines. The Feather River Canyon, where the fire began, has peak wind speeds ranging from 60 to 100 mph. Yet for nearly nine decades after acquiring the Great Western assets, PG&E made little effort to determine the condition of the tower equipment and replace aging components.

At some point between 1921 and 2018 — date unknown — replacement hanger brackets were added to the tower because of “keyholing” resulting from the C hook rubbing on the original hanger hole. But investigators concluded after the Camp Fire that the transposition arms, C hooks, insulator strings and jumper conductor were all original components.

Reduced Inspections

Investigators found evidence that PG&E was aware of the problem of C hook and hanger wear in 1987. Photos of the worn C hooks and holes were distributed to troublemen — a job title created by PG&E in the 1980s for what were supposed to be transmission line experts. Inspection of C hooks and hanger holes was identified as a priority.

But rather than increasing its scrutiny over its aging towers, PG&E continually reduced its inspections. In 1995, monitoring of the Caribou-Palermo line was reduced from one ground patrol and two aerial inspections per year to one ground inspection and one aerial inspection every two years. Inspections that required climbing the towers, previously routine requirements, were eliminated.

The new rules said climbing inspections were required only if “triggered” by one or more specific conditions. But the company “interpreted the mandate of ‘require’ as discretionary,” Butte County said. Between Jan. 1, 2017, and Feb. 21, 2017, there were at least nine storm-related interruptions and at least six equipment failures on the Caribou-Palermo line, each one qualifying as a “trigger.” Yet no climbing inspections were conducted, the report said.

In 2005, the Caribou-Palermo line was reduced to only one inspection every five years and one patrol per year in non-inspection years. (PG&E at times differentiated between patrols and more detailed inspections; at other times, the terms were used interchangeably.)

Missed Opportunity

In 2012, PG&E hired Quanta Technology to review the utility’s ground patrols of overhead transmission lines, concluding that its Electric Transmission Preventative Maintenance Manual (ETPM) was “a comprehensive, well written document.” But Quanta did not evaluate whether the company was following the manual, and investigators concluded that PG&E was not doing so. “Based upon the evidence, it is reasonable to conclude that sections of the ETPM relating to inspections and patrols of overhead electric transmission lines were simply a façade created to meet the requirements of the regulators and the CAISO.”

PG&E also ignored Quanta’s recommended improvements, failing to adopt any new policies or procedures for inspection of the oldest transmission assets, the report said. “There is no evidence of a programmed sampling of the oldest structures and foundations. Even the collapse of five Caribou-Palermo line structures in 2012 did not cause PG&E to take a closer look at one of their oldest transmission assets.”

Reducing Costs

Instead, in 2013, PG&E formed a committee to look for ways to cut inspection costs, with a focus on reducing the “unit costs,” calculated based on the time that a troubleman spends inspecting an individual structure.

The committee reduced the unit costs by “reducing the thoroughness of the inspections and patrols,” investigators said, noting that transmission line supervisors’ and superintendents’ bonuses were based in part on meeting the inspection and patrol budget.

“The time allotted to be spent on a single structure was a system-wide constant and did not take into account the physical location of any specific structure or the amount of time necessary to travel from structure to structure,” the report said. “For example, the time allotment assumed the inspection of a tower on the Caribou-Palermo line, parts of which could be accessed only by hiking a steep trail, would take the same amount of time as inspecting a tower in the Central Valley, located directly adjacent to a public roadway.”

Lack of Training

Butte County said it interviewed every qualified company representative (QCR) who had inspected or patrolled the Caribou-Palermo line since the publication of the ETPM in 2005. None, the county reported, said they had received any formal training on how to perform an inspection. “The only training on how to perform an inspection or patrol was via informal mentoring by other, more experienced, troublemen,” the report said.

Some of the inspectors had little or no transmission line experience before becoming a troubleman, the report said, and none were provided tower schematics or other records specific to the lines being inspected.

“Both of the ‘detailed ground inspections’ [in 2009 and 2014] and seven of the ten annual air patrols on the Caribou-Palermo [line] were completed by troublemen who had little or no prior transmission experience, and no formal training on performing inspections and patrols,” the report said.

The ETPM required the QCRs to examine components and estimate wear by percentage of material lost. “In order to judge material loss, a troubleman would have to know what a component looked like at 100%,” the report said. “The majority of the [troublemen] sent to inspect and patrol the Caribou-Palermo line had no idea what the C hooks and hanger holes were supposed to look like. Because of their lack of knowledge, experience and training, the [troublemen] could not have been expected to identify the wear.”

Between 2001 and 2018, aerial patrol by helicopter was the primary method for inspecting the Caribou-Palermo line. But a transmission line supervisor told investigators that the wind and topography made it unsafe for the helicopters to fly low enough and slow enough to enable the troublemen to inspect the C hooks and hanger holes. The troublemen also said it was impossible to assess the wear on the components from a ground inspection.

Capital vs. Expenses

PG&E electrical transmission expenses were divided into two budget categories: capital costs, funded through customer rates determined by FERC rate cases, and an expense budget funded by the company. In 2015 and 2016, investigators said PG&E reduced the expense budget, in part by charging some expense projects to the capital budget.

“Moving projects from the expense budget benefits PG&E in two ways,” the report said. “First, every expense budget dollar saved [is] an additional dollar of potential profit. Second, the customers (ratepayers) pay over 100% of each dollar spent on capital improvements that brings in additional profit. Based upon internal emails and interviews with engineers involved in the planning and management of transmission projects, it was common for PG&E to look for ways to bootstrap expense budget projects on to capital budgets projects.”

PG&E had told FERC during a 2018 transmission rate case that the company needed to shift its capital investments from capacity increase projects to lifecycle replacement projects to address its aging infrastructure. But investigators said the company “was not using the money to replace the oldest and most deteriorated transmission assets.” Instead, investigators found PGE’s “maintenance/repair/replace” budget was primarily based on statistical analyses of outage data.

‘Run to Failure’

After the Camp Fire, investigators concluded that the Caribou-Palermo line “was only marginally worse” than other comparison transmission lines. “Records from post-Camp Fire enhanced inspections of other, similar lines clearly established PG&E’s problems were systemic as opposed to local,” they said.

Investigators concluded that in mountainous, low population density areas, PG&E did not follow the ETPM and regulatory requirements but instead practiced a “run to failure” approach.

PG&E used a “comparative risk analysis” called the risk informed budget allocation (RIBA) to prioritize potential capital projects. RIBA evaluated the consequence of not completing a project based on the number of customers impacted by a potential failure and the outage duration.

Butte County said it found evidence that projects used to justify rate increases in FERC rate cases were “later not funded because of a low RIBA score.”

Investigators found documents dated 2017 that they said summarized PG&E’s transmission asset management risk strategy, with proactive replacements for high-risk assets and a “run to failure” approach for low-risk assets: “minimal” patrols, “no maintenance,” and “only replacement no repairs.”

Although the company in 2018 replaced the term “run to failure” with “run to maintenance,” investigators said the change “was semantical only.”

PG&E’s reliability metrics measured the number of customers who lose power as a result of an outage and the duration of the outage, information required to be reported annually to the California Public Utilities Commission, CAISO, the Western Electricity Coordinating Council, NERC and FERC.

Thus, 500-kV lines, which can potentially affect millions of customers, were subjected to annual patrols and detailed ground inspections every three years, with “critical” 500-kV structures receiving climbing inspections every three years (barring triggers) and “non-critical” 500-kV structures subject to climbing inspections every 12 years.

“In contrast, 115-kV structures were subjected to detailed ground inspections every five years, air patrols in non-detailed ground inspection years and [were] never subjected to climbing inspections,” the report said.

With only one dedicated customer — the Caribou Powerhouse — that could be affected by an outage, the Caribou-Palermo line scored poorly, the report said. “The only reasonable conclusion to be drawn from the totality of the evidence is that PG&E was employing a run to failure strategy on the entirety of the Caribou-Big Bend section of the Caribou-Palermo line. Pursuant to the run to failure strategy, PG&E only applied a low degree — or patrol with minimal frequency — to continuously assess risk, and only performed corrective maintenance.”

Last Chance to Avoid Catastrophe

PG&E had one last opportunity to avoid catastrophe when a supervisor issued a work order in 2018 requiring climbing inspections of all Caribou-Palermo line structures. Investigators said that PG&E was unable to explain the reason for the work order but that PG&E crews performed climbing inspections on 80 towers on the line in September and October 2018. The report does not say what, if any, repairs were ordered as a result.

After the Camp Fire, however, all of the towers climbed previously were subjected to “enhanced” inspections, which the report said “documented problems and defects on numerous towers” not identified in the earlier visits.

“The fact that PG&E has no explanation for how or why or by whom the decision to conduct climbing inspections was made is disturbing but not unusual,” the report said. “… As to many decisions and policies, PG&E was unable to provide any documentation as to who made the decision, how the decision was made and upon what the decision was based. This inability to determine who made decisions and upon what those decisions were based frustrated efforts to identify individuals potentially personally liable for policies that [led] to the conditions which caused the Camp Fire.”

Sentencing

PG&E was sentenced Thursday to pay nearly $3.5 million in fines for its criminal culpability in starting the Camp Fire and the 84 resulting deaths. Although the district attorney said it could not charge any individual PG&E officials with crimes, it asked the court to impose the maximum punishment for a corporate defendant under California law. (See PG&E Sentenced as Bankruptcy Nears End.)

The report cited numerous aggravating factors and only two mitigating factors the court should consider in sentencing: that the utility had agreed to plead guilty and to make restitution.

“The fact that PG&E relied on a 97-100-year-old C hook it knew nothing about to hold an energized 115-kV conductor is, by itself, negligent and reckless. It is also disturbing that PG&E’s only information of the composition of the conductor running through Tower 27/222 comes from a 1922 article in an engineering journal,” the report said. ” … The fact that PG&E was using a 97-100-year-old conductor for which they knew almost nothing is evidence of absolute indifference on the part of PG&E.”

Although updated NERC guidelines forced PG&E to replace conductors on some segments of the Caribou-Big Bend section, it left the 97-year-old aluminum steel reinforced conductor in other areas.

“Since at least 2006, PG&E has recognized bad things, especially fire, happen when equipment failures occur on transmission lines. Everything in the overhead electric transmission system is designed to keep the conductor hanging in the air and away from persons or objects it could harm. Despite this knowledge, PG&E put almost no effort into ensuring the components that keep the extremely dangerous overhead transmission lines hanging safely in the air were safe,” the report said.