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topicnews · August 29, 2024

Electric vehicles are no more likely to catch fire, but Colorado firefighters are preparing for the challenge of burning batteries

Electric vehicles are no more likely to catch fire, but Colorado firefighters are preparing for the challenge of burning batteries

On Monday, a driver died in a serious accident involving an electric car and several lanes of Interstate 25 had to be closed. Although the use of battery-powered vehicles is increasing in Colorado, electric cars are no more prone to fire than conventional cars, according to safety groups.

According to the National Transportation Safety Board, fire departments respond to approximately 170,000 vehicle fires each year, mostly involving passenger vehicles. Between 2013 and 2017, there was an average vehicle fire every 2-3 minutes, according to data from the National Fire Protection Association.

According to the firefighters association, there are fewer electric vehicle fires than typical gasoline-powered vehicle fires, but there is little high-quality data on their exact frequency. Colorado Department of Transportation crash data does not distinguish between electric vehicles and those without batteries, and federal agencies do not maintain a database of electric vehicle fires.

One study estimated the number of electric vehicle fires at 25 fires per 100,000 vehicles. However, according to a report in Car and Driver, the results of this study appear to be limited and the data sources are questionable.

According to state and federal data from May 2024, the Tesla Model Y is the most widely used electric vehicle in Colorado. Tesla’s own analysis of the fire risk of its vehicles shows that fires in Tesla vehicles occur much less frequently than the U.S. average for all vehicles.

“Definitely harder to delete”

Electric vehicle fires burn differently than gasoline-powered car fires, which can complicate firefighters’ response. Most electric vehicles on the market today are powered by lithium-ion batteries, which also power devices such as cell phones, laptops and digital cameras. However, electric vehicle battery modules are much larger than those used in personal electronic devices, and when they catch fire, a phenomenon called thermal runaway can occur.

Thermal runaway releases heat and flammable gases into the air near the battery, which in turn creates even more heat and can even cause the battery to explode. Thermal runaway, coupled with the fact that lithium-ion cells can reignite after being extinguished, means that EV batteries can burn longer than fires in a typical car or pickup truck.

In 2020, the National Transportation Safety Board highlighted a number of safety risks for first responders to electric vehicle fires, including electrocution and battery reignition. In one case, firefighters dumped thousands of gallons of water on an electric vehicle, not knowing that the battery compartment was actually at the bottom. The battery then reignited several times on a tow truck and at a tow yard.

“Electric vehicle fires are clearly more difficult to extinguish than combustion engine fires,” said Brian Willie, spokesman for South Metro Fire Rescue, which responded to the electric vehicle accident on Monday.

Fire Department South

South Metro Fire Rescue responds to a fatal accident involving an electric vehicle that caught fire on I-25 south of Denver on August 26, 2024.

But how exactly firefighters extinguish an electric vehicle fire depends on the situation and location, according to Todd Bower, deputy chief of the Denver Fire Department.

“We have dry chemical fire extinguishers that can help in the fight, depending on what is actually burning,” Bower said. “Usually large amounts of water are used.”

Bower said water supplies in the Denver metro area are usually adequate through fire hydrants that can supplement the 500-gallon tanks commonly found in trucks, but some electric vehicle fires have required 36,000 gallons of water to extinguish.

South Metro Fire Rescue, which covers the southern Denver metropolitan area, uses automotive blankets as part of its electric vehicle firefighting arsenal. Large blankets are nearly 600 square feet in size and are thrown over burning vehicles to cut off oxygen to the burning battery. The blankets, which can cost up to $2,000 for a reusable model, don’t completely extinguish the flames but help cool the fire until the battery is fully burned, according to the manufacturer.

Other fire departments are taking their cues from how South Metro crews are adapting to fighting a new type of vehicle fire, Willie said. “We get calls every day based on the videos we’ve released and from other departments across the country following our guidelines on using the blankets,” Willie said.

South Metro’s typical procedure for putting out an EV fire is to call in a hazmat crew and a fire truck and use a fire blanket to douse the flames as much as possible, Willie said. A tow truck then moves the blanket-covered EV into a yard, followed closely by a fire truck. The EV will be isolated for at least “a couple of weeks” to allow the fire to fully die down.

Because Monday’s fire was originally reported as a hybrid car and was largely extinguished with water, firefighters did not use a fire blanket, Willie said.

More electric vehicles mean first responders are better trained to fight fires. The International Association of Fire Chiefs publishes an Electric Vehicle Fire Bulletin for fire departments that recommends backing up to 8,000 gallons of water from a tanker truck when no hydrant is accessible and monitoring for batteries reignition. The National Fire Protection Association also publishes guidelines from electric vehicle manufacturers on how firefighters should handle certain vehicles in an emergency.

Although there have been some notable electric vehicle fires in the Front Range recently, there is no concrete, publicly available data to suggest that electric vehicles are more prone to fires than gasoline-powered vehicles.

“In operations like the one at South Metro recently, I’ve noticed that we’re not seeing an increase in fires involving any particular vehicle or system type,” said Bower of the Denver Fire Department.

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