A lawsuit points a finger at Pacific Gas & Electric Co. alleging the utility failed to adequately protect its power lines before the Northern California deadly wildfires.

The lawsuit, filed on behalf of Santa Rosa homeowners, Wayne and Jennifer Harvell, says drought-like conditions over the summer put fire dangers "at an extraordinarily high level," particularly after heavy winter rains increased vegetation. It says PG&E failed to trim and remove vegetation as it should have.

PG&E Corp., the utility's parent company, said earlier this month, Cal Fire was investigating its power lines and equipment as a possible cause of the fires that killed at least 41 people and destroyed 6,000 homes. The California Public Utilities Commission (PUC), which regulates PG&E, said it would investigate only if state fire investigators find that the utility's equipment is a suspected cause of the deadly fires. If found at fault, this could lead to significant fines and penalties for PG&E.

However, the utility said it's not speculating on the cause of the fires and that it was cooperating with investigators.

If found responsible, this wouldn't be the first time PG&E faces a crisis, but it could potentially be the worst incident the utility is held accountable for.

San Bruno pipeline explosion

California regulators fined the company $1.6 billion for the 2010 natural gas explosion in San Bruno that killed eight people and destroyed 38 homes. The fine, approved in 2015, was the largest in PUC history and one of the largest paid by a U.S. utility, according to the Los Angeles Times.

The explosion revealed questionable safety practices with pipelines and within company culture.

Earlier this year, a San Francisco judge imposed the maximum sentence allowed by law against PG&E for violating pipeline safety standards before and after the San Bruno gas pipeline explosion. The utility was convicted of six felony charges stemming from the explosion.

One of the charges included a felony obstruction count. The panel, found PG&E officials had attempted to derail the San Bruno investigation by denying a practice of pumping natural gas through aging pipelines at high pressures, according to the San Francisco Chronicle.

PG&E's sentence included a $3 million fine, a five-year probation period, independent safety monitoring and 10,000 hours of community service, according to KGO.

Additionally, the company was ordered to take out full-page ads in the San Francisco Chronicle and Wall Street Journal and to buy television ads, explaining the nature of PG&E's offenses and the steps they're taking to prevent future incidents.

Butte Fire

Last year, Cal Fire investigators determined the 2015 Butte Fire was sparked after a tree made contact with a PG&E power line. The fire burned for 22 days and spread into Calaveras County before the blaze was fully contained at 70,868 acres. In the end, the fire took the lives of two people and destroyed more than 900 structures.

Cal Fire officials claimed PG&E was responsible for the more than $90 million in costs the department spent fighting the fire.

In April, The PUC announced an $8 million fine against the utility for poor tree maintenance by PG&E and its contractors and for failing to report one of its power lines may have started the blaze.

The Butte Fire is the seventh-most destructive wildfire in California history.