ap photo In this 2018 file photo, a vehicle rests in front of a home leveled by the Camp Fire in Paradise, Calif.

SAN FRANCISCO — A scathing grand jury report released Tuesday after a 2018 Northern California wildfire killed 85 people found that Pacific Gas & Electric officials repeatedly ignored warnings about its failing power lines, performed inadequate inspections to focus on profits and refused to learn from past catastrophes.

PG&E exhibited “a callous disregard” for the life and property of residents before its equipment ignited the most destructive wildfire in recent U.S. history, a summary of the grand jury investigation said. Investigators concluded the primary cause of the fire was a nearly century-old suspension hook that failed, worn through after decades hanging in a windy canyon.

“Through a corporate culture of elevating profits over safety by taking shortcuts in the safe delivery of an extremely dangerous product — high-voltage electricity — PG&E certainly lead otherwise good people down an ultimately destructive path,” the 92-page summary released Tuesday said.

In response, the country’s largest utility pleaded guilty Tuesday in Butte County Superior Court to 84 felony counts of involuntary manslaughter. The company maintains that it cherishes public safety above all else.

Prosecutors say they discussed charging utility individuals but decided they lacked the evidence to do so, which means there is no one to imprison for the crimes. PG&E instead will pay a maximum fine of $3.5 million and $500,000 to cover the county’s costs of the criminal investigation.

The fire was the most destructive U.S. wildfire in a century, demolishing more than 18,000 homes and other buildings, mostly in the town of Paradise about 170 miles (275 kilometers) northeast of San Francisco. Butte County District Attorney Michael Ramsey charged 84 deaths, saying he could not prove the utility caused one of the deaths.

Those who died were mostly elderly or disabled — the oldest 99 and the youngest 20. Their remains were found in showers and bathtubs, clutching a beloved photograph, cuddling pets, trapped in getaway cars and even seeking safety under a vehicle.

TK Huff of the nearby town of Concow was found outside his home, 10 feet (3 meters) from his wheelchair. Evidence suggested the 71-year-old tried to drag himself away to escape the fire, the report said.

Three generations of the Heffern family — Christina, Ishka and Matilde — called 911 as the fire raced toward their Paradise home and, with the phone line still open, helpless “dispatchers listened to their screams.”

The Camp Fire Public Report paints a damning picture of PG&E as an entity that regularly shirked accountability and was shameless in its unwillingness to learn from past failures. The San Francisco-based utility was convicted in 2016 of multiple federal felonies after one of its gas transmission pipes exploded in the San Francisco suburb of San Bruno, killing eight people.

The fire in Paradise, dubbed the Camp Fire, broke out in the early morning amid dry, gusty weather; it was unlike anything firefighters had seen before. Whipped by fierce winds, it scattered softball-sized embers every which way, trapping residents in walls of fire.

Investigators determined the cause of the main fire was a suspension “C” hook on a transmission tower that had worn through after decades hanging in Feather River Canyon.