Last years deadly Camp Fire , the worst in Californias modern history, was caused by power lines owned by Pacific Gas and Electric, or PG&E, local fire officials said Wednesday.

After a very meticulous and thorough investigation, CAL FIRE has determined that the Camp Fire was caused by electrical transmission lines owned and operated by Pacific Gas and Electricity, Cal Fire said in a statement on Wednesday.

The agency noted that a confluence of factors caused terrible fire conditions, including tinder dry vegetation and strong winds that promoted this fire and caused extreme rates of spread.

Cal Fire also said that the PG&E lines caused separate ignitions at two different sites, but that one fire was consumed by the other to create a unified blaze.

PG&E said in February it was probable that its equipment caused the blaze, which killed 85 people, destroyed nearly 14,000 homes and scorched more than 153,000 acres. In January, the company filed for bankruptcy protection after saying it faced up to $30 billion in liabilities from wildfires in California, in large part due to the scale of the Camp Fire.