SAN FRANCISCO (AP) – California officials say they will seek more than $90 million in firefighting costs from Pacific Gas & Electric Co. after finding that a deadly 2015 fire was sparked by a tree that came into contact with a power line.

The California Department of Forestry and Fire Protection released a report Thursday detailing the cause of the fire in Calaveras and Amador counties.

The amount is believed to be the largest recovery amount ever sought by Cal Fire, said spokeswoman Janet Upton.

Cal Fire said the state’s largest utility or its contractors had removed two gray pine trees from a stand in January 2015, exposing a weaker, skinnier interior tree.

The 44-foot-tall gray pine tree grew taller, seeking the sun, but eventually slumped into a power line, according to the report.

The blaze started Sept. 9 and burned for three weeks. It killed two people and destroyed more than 900 structures, including some 550 homes.

The fire caused an estimated $300 million in insured losses and is the seventh-most destructive wildfire in state history.

PG&E has issued the following statement regarding the investigation:

“First and foremost, our thoughts and prayers continue to be with the victims and the communities who suffered losses as a result of the Butte fire. We are committed to doing the right thing for them and to promptly resolving their claims. We have already begun to address many claims.

We want to thank CAL FIRE and all first responders for their bravery and commitment in responding to this major fire. We cooperated fully with CAL FIRE’s investigation of the fire and we appreciate the thoroughness of its report.

Based on our preliminary review, we accept the report’s finding that a tree made contact with a power line, but we do not believe it is clear what caused the tree to fail or that vegetation management practices fell short.

Effective vegetation management is critically important to fire safety and we want to reassure all of our customers and their families that we are unequivocally committed to their safety. We monitor approximately 50 million trees a year and we trim or remove more than one million trees annually.

Our vegetation management program is among the very best in the industry and was expanded in 2014 in response to California’s historic drought to include special air and foot patrols, funding for lookout towers and cameras for early fire detection and funding for fire fuel reduction and emergency access projects and public education.

Despite these efforts, we recognize the hardships that this terrible fire caused and we are committed to helping our friends and neighbors recover.”