What causes a car to catch on fire?

On the Road 3 min read

While modern cars are generally safe, there are several potential causes of car fires that pose a risk for any vehicle. Some makes and models of cars may be more susceptible to destructive blazes, such as electric vehicles with lithium-ion batteries that are prone to car battery fires. But just about any vehicle on the road, whether gas-powered, electric, or hybrid, can catch on fire due to leaky fluids, electrical problems, or other issues.

Common causes of car fires

All in all, car fires are rare in the United States. According to the National Fire Protection Association, just over 117,000 car fires were reported on average between 2013–2017. While this may sound like a big number, Car and Driver points out that there were more than 261 million registered U.S. vehicles in 2018. That means that around 0.04% of cars catch fire in any given year — a small percentage, to be sure, but for those cars that do catch on fire, the damage can be significant. Learn about if car insurance covers fire damage.

So what are some common causes of car fires? Here are several recurring causes of automotive blazes today:

  • Electrical issues: Cracked or loose wiring can spark, creating a potentially hazardous situation. While wiring can deteriorate due to old age, sometimes rodents gnaw on the cords, increasing the risk of fire damage. Learn about insurance coverage for damage from wild animals. Improperly installed aftermarket accessories can also increase the chances of a fire if wires are inadvertently damaged.
  • Leaking fluids: The fluids that help keep your car moving can be dangerous if they aren’t contained properly. Oil spills from a sloppy oil change can quickly heat up on a hot surface, and in a worst-case scenario, ignite. Learn about keeping your car current on maintenance.
  • Catalytic converters: The purpose of a car’s catalytic converter is to reduce pollution-causing emissions. According to the Texas Commission on Environmental Quality, it does this by accelerating the combustion of the pollutants that come out of a vehicle’s engine. This causes extreme heat under the car, with temperatures approaching 1,000 degrees Fahrenheit in some cases. While catalytic converters are protected by a heat shield, sometimes those are accidently dislodged from vehicles. A hot catalytic converter can ignite dry grass or other debris under the car, which can quickly spread to the vehicle itself.
  • Overheating engines: Lack of coolant, radiator leaks, and other factors may cause an engine to overheat. Uncontrolled heat under the hood can lead to a fire. The best thing to do if your engine overheats is to stop the car in a safe place. Continuing to drive could cause permanent damage to the engine, as well as being an increasing fire hazard.
  • Cigarettes: Simply lighting a cigarette or cigar in a vehicle increases the risk of a car fire. Car fires have even started from drivers or passengers unsuccessfully attempting to toss out a still-hot cigarette or cigar through a window — only to have it fall onto the floor or fly back in through an open backseat window.

Electric vehicle fires

While all car fires are dangerous, electric vehicle fires can be particularly destructive. According to the Boston Globe, gas-powered car fires are more common than fires in electric vehicles. However, the lithium-ion batteries used in electric vehicles make fires in these kinds of vehicles harder to extinguish. The lithium-ion battery cells don’t require outside oxygen to burn, unlike gas-powered fires, and an EV fire can easily spread between battery cells.

In general, the larger the battery, the more potential for a larger electric car battery fire. As technology and consumer preferences lead to bigger electric vehicles hitting the road, bigger lithium-ion batteries will too. Learn about battery maintenance for electric vehicles.

How to prevent a car fire

Of course, if at all possible, it’s best to prevent car fires before they start. The U.S. Fire Administration has some tips to minimize the danger whenever possible:

  • Have your vehicle serviced regularly by a mechanic
  • Drive safely to avoid accidents
  • Tightly seal gas cans or propane tanks, and place them on a flat surface to keep them upright
  • If you transport flammable liquids, open your windows to let fumes escape

Knowing the potential car fire hazards can help you stay safe behind the wheel. Be sure you know what to do if your car breaks down on the highway.

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