Other Fire Causes

While utility company power lines commonly cause California wildfires, a significant portion are sparked by other ignition sources. A small percentage of the state’s wildfires are attributed to natural causes, but roughly 90% are human-caused.

As California’s population expands farther into wildland country, more and more Californians are at risk, particularly in areas where wood fuel has accumulated. Climate change has also attributed to longer wildfire seasons and hot, dry weather conditions that make vegetation prime for ignition.

Whether it was intentional, accidental, reckless, or preventable, human activity has caused the majority of the most destructive and deadly wildfires in the state’s history. With conditions worsening, preventative measures are more important than ever. Legal accountability has and continues to be a necessary action in California when any entity is irresponsible or deliberately harmful, be it a company or individual(s).

Eight of the most common ignition sources in California are:

Power Lines

Equipment-Generated Sparks





Children-Playing with Fire


Other Fire Causes in California: Overview and List of Examples

Natural Causes

Lightning fires are often more difficult to control than human-caused fires because they can ignite miles from roads in terrain that’s challenging to traverse. Besides the Sierra Nevada and the northernmost part of the state, lightning is actually not very common in California. In 2022, UCLA climate scientist Daniel Swain said, “Coastal California sees some of the least lightning of almost any place on earth, actually — and certainly in the U.S.” 

Still, lightning is a significant ignition source in California and in some cases is believed to have intensified already-lit fires, such as the McKinney Fire. According to environmental research, lightning started 28.5% of California wildfires between 1987 and 2020 and caused 50% of the burnt land. Another study indicates lightning strikes could increase due to global warming, predicting that strikes will increase by 12% with every degree warmer it gets.

August 2020 Lightning Fires

Lightning often strikes repeatedly in the same area, causing tens or even hundreds of fires that overwhelm firefighters. Such was the case with the August 2020 lightning fires, in which 650 fires ignited across Northern California. This included the SCU Lightning Complex, the August Complex, and the LNU Lightning Complex fires. The fires burned over 2.5 million acres, destroyed over 3500 buildings, and killed 23 people. 

2020 Creek Fire

Lightning was the probable cause of the Creek Fire that burned 379,895 acres in Fresno and Madera County. 

2012 Rush Fire

The Rush Fire burned 271,911 acres in California and 43,666 acres in Nevada and was the largest wildfire of the season. 

Accidental Ignition

Careless actions, such as leaving unattended campfires, discarding lit cigarettes, or improper disposal of burning materials can spark wildfires. The charges brought against individuals vary greatly case-by-case. 

2020 El Dorado Fire

The El Dorado Fire was caused by a pyrotechnic device at a gender reveal party in El Dorado Ranch Park. The fire burned 22,744 acres, damaged or destroyed 16 structures, and killed 1 firefighter. As of January 2023, Refugio Manuel Jimenez Jr. and Angelina Renee Jimenez faced one count of involuntary manslaughter, three felony counts of recklessly causing a fire to an inhabited structure, three felony counts of recklessly causing a fire with great bodily injury, and 22 misdemeanors to recklessly causing a fire to the property of another. The couple’s fate will be decided by a jury. 

2003 Cedar Fire

The Cedar Fire was caused by a hunter who got lost in the Cleveland National Forest and lit two fires to signal for help. Sergio Martinez pled guilty to starting an illegal fire and was sentenced to six months in a work furlough program, 960 hours of community service, and 5 years probation. Martinez initially lied to investigators, saying the fire was sparked by a shot from his rifle. This charge was dropped. The fire burned 280,278 acres, destroyed 2,820 buildings, and killed 15 people.


Deliberately set fires by individuals with malicious intent pose a significant threat. Arson cases can result in widespread destruction and endanger lives. Punishment is often severe for arsonists. 

2022 Oak Fire

The Oak Fire ignited in Mariposa County, burned 19,244 acres, and destroyed or damaged 203 buildings. Ex-firefighter Edward F. Wackerman faces felony charges for aggravated arson, arson that causes great bodily harm, and arson causing damage or destruction of inhabited structures.

2006 Esperanza Fire

The Esperanza fire burned 41,173 acres, damaged or destroyed 54 buildings, and killed 5 firefighters. Raymond Lee Oyler was suspected of starting a number of fires, including the Esperanza Fire, and would be convicted of 20 counts of arson and 17 counts of using an incendiary device. He was convicted of first-degree murder for the Esperanza Fire and sentenced to death in 2009. He is believed to be the first arsonist in the U.S. to be convicted of murder for setting a fire. 

Equipment Use and Malfunctions (Not Utility Related)

Equipment use (lawnmowers, chainsaws, grinding equipment) and malfunctioning machinery can generate sparks, which, when combined with dry vegetation, can quickly escalate into destructive wildfires. Industrial activities involving flammable materials or processes also contribute to fire outbreaks.

2022 Mill Fire

The Mill Fire ignited in Siskiyou County, burned 3,939 acres, damaged or destroyed 144 structures, and killed 2 civilians. CAL Fire determined the fire was caused by mill operations at Roseburg Forest Products. Roseburg officials had previously announced that they believed the fire ignited due to the possible failure of a water-spraying machine used to cool ash. Civil lawsuits alleged the company prioritized profits over safety and the investigation’s findings have been forwarded to the Siskiyou County District Attorney’s Office. 

2007 Zaca Fire

The Zaca Fire was started by sparks from a grinding machine that was being used to repair a water pipe. Five felony counts were brought against two ranch workers (Jose Jesus Cabrera and Santiago Iniguez Cervantes) but were later dismissed as the judge felt actions did not amount to recklessness. Cabrera, who was in charge, was sentenced to 3 years probation. The fire burned 240,207 acres and destroyed 1 building. 

2004 Bear Fire

The Bear Fire was sparked in Shasta County by a lawn mower that struck a rock in dry grass. Prosecutors said William Rupp ignored warnings not to mow from neighbors and the public. He was convicted of arson, spent two years in state prison, and was ordered to pay $2.25 million to his neighbors. 

Learn More About California Fire Culprit Lawsuits

Read more about wildfire lawsuits that have been attributed to arsonists, accidental ignition, equipment use and malfunction, and other causes. For more information about wildfires caused by California utility companies, visit our California Wildfire Lawsuit page.

Please note the Border 32 Fire is still under investigation.