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What First Responders Don’t Know About Fiery Electric Vehicles
Lithium-ion batteries, once ignited, are extremely difficult to douse.
By Chester Dawson
25 March 2019, 10:00 UTC
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Illustration: Rina Barbarić
After an out-of-control Tesla Model S plowed into a stand of palm trees on a highway median outside Fort Lauderdale last month, police rushed to put out the ensuing blaze using a department-issued fire extinguisher. It was a wasted effort. The car kept on burning after the crash, which killed the driver.
The police may not have known lithium-ion batteries inside electric vehicles, once ignited, can’t be put out with chemicals from a conventional extinguisher. The battery fires are susceptible to a self-destructive chain reaction known as thermal runaway, causing a feedback loop of rising temperatures. The Tesla fire stumped a series of first responders in Florida. Firefighters eventually doused the flames with water, which seemed to work, but the wrecked car reignited twice more after being towed away. That prompted what a police report later termed “extraordinary measures,” including a call to Broward County’s hazmat unit for advice on stamping out the fire once and for all.
The accident illustrates the challenges faced by first responders unfamiliar with the special characteristics—and hazards—of electric vehicles’ powertrains. Safety experts say the only way to extinguish a lithium-ion battery inside a car is with thousands of gallons of water, much more than what it takes to stop a fire in a typical gasoline engine. The other option is to just let it burn itself out. “It’s such a difficult fire because it takes so much water to put out,” said Robert Taylor, fire marshal in Davie, Fla., where the crash occurred.
Tesla crash AP Photo
Emergency personnel work at the scene where a Tesla SUV crashed into a barrier on Highway 101 in Mountain View, Calif., on March 23, 2018.
Source: KTVU via AP
In addition to fires, emergency responders dealing with EVs face risks from high-voltage cables and silent-running motors. The experience taught Taylor’s team important lessons about dealing with electric vehicles. “For us,” he said, “it’ll be the awareness of auto-ignition of the battery and knowing how long the energy remains in them.”
In an emailed statement, Tesla Inc. called the accident tragic and said it had reached out to first responders to offer cooperation. The company also noted that vehicle fires aren’t unique to EVs. “We understand that speed is being investigated as a factor in this crash,” the company wrote, “and know that high speed collisions can result in a fire in any type of car, not just electric vehicles.”
While one witness said the car “flew” past him, police said it was traveling at the posted speed limit of 50 miles per hour.
With more than 760,000 electric and plug-in vehicles on the road in the U.S., according to the International Energy Agency, emergency responders with little past exposure to these cars are becoming more likely to encounter one at a crash scene. The U.S. National Transportation Safety Board is already investigating multiple incidents involving EV battery fires and problems encountered by emergency personnel. The agency plans to issue a set of recommendations based on four reference cases by late summer or early fall. “That will be the first major report addressing the issue,” said NTSB spokesman Chris O’Neil.
Electric vehicles are no more prone to accidents or fires than gasoline-powered cars—and might be less so, according to a 2017 report by the National Highway Traffic Safety Administration. That report also notes battery technology is still evolving, without any consensus on safe system design. Battery-powered cars remain a tiny minority in the U.S., with sales of EVs accounting for just 1.2 percent of total new vehicles delivered in the U.S. last year, according to data from Edmunds.
But the expectation that EV sales will rise sharply within the next five years makes it critical to educate first responders and develop new standards that make identification and troubleshooting easier for police, firefighters, and tow truck operators. So far about 250,000 of the roughly 1.1 million firefighting personnel in the U.S. have undergone some form of EV training, according to estimates from the National Fire Protection Association.
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The battery pack of a disassembled Tesla Model 3.
Photographer: Sean Proctor/Bloomberg
“First responders have 100 years of experience dealing with internal combustion engines, but it’s a very different situation when it comes to EVs ,” said Andrew Klock, program manager for emerging technology at NFPA, a nonprofit based in Quincy, Mass. “Every time an EV catches fire, we get a lot of calls” from emergency management coordinators, he said.
The NFPA began conducting training and creating reference manuals about a decade ago just as the Chevy Bolt and Nissan Leaf were about to debut. It has worked closely since then with General Motors Co. and other automakers to educate first responders about what wires to avoid, where critical components are located under the hood, and how to control battery fires. The NFPA provides check sheets for most makes and models.
Tesla also regularly meets with first responders and donates its cars for training purposes. But there’s only so much that can be done once battery cells begin to spontaneously explode. The company’s online emergency response guide notes: “Battery fires can take up to 24 hours to extinguish. Consider allowing the battery to burn while protecting exposures.”
One of the first things first responders learn: Never cut an orange cable, a color reserved for wiring in excess of 60 volts. These can be found not just in the front or rear of a car but also running behind side panels. Most gasoline-powered vehicles have no orange cabling at all, since they use electrical charge powered by a standard 12-volt battery. A typical EV operates at closer to a potentially deadly 400 volts. The all-new Porsche Taycan, for example, will boast double that amount of electrical charge when it goes on sale later this year.
Higher voltages are part of a trend designed to maximize efficiency and boost horsepower. “We think you could see a world of 1,200 volts” for vehicles in a few years, said Mary Gustanski, chief technology officer at Delphi Technologies Plc, a major automotive powertrain supplier. But she said advanced componentry could eventually do away with most high-voltage cabling.
The orange color coding was one early step taken by automakers to aid first responders and auto repair technicians. Other efforts include standardizing instructional materials and advocating three-sided badging on vehicles to help identify EVs. That’s being shepherded by a Society of Automotive Engineering task force, which includes representatives from 11 automakers as well as auto suppliers and government officials. The SAE is expected to update those guidelines later this year with more recommendations, such as using an “e” (for electric) as a prefix or suffix on nameplates of newer EVs. Officials say future revisions may include calls for a kill switch to cut off power under the hoods of electric vehicles.
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Countries outside the U.S. also are grappling with the issue of familiarizing emergency response crews with electric cars. In 2016 firefighters in a small town in Norway allowed a Tesla to burn to the ground at a charging station, leaving only the charred remains of the frame and wheels, because they mistakenly feared using water could lead to an electric shock. Later that year, firefighters in the Netherlands delayed extracting the body of a deceased Tesla driver involved in a crash due to fear of electrocution if they cut a wire in the car’s frame.
In the aftermath of that incident, Dutch authorities turned to one of the leading authorities on Tesla vehicles involved in accidents: the fire department in Fremont, Calif., where the automaker’s factory is located. The department has ample experience responding to EV-related incidents, including a fire at Tesla’s plant earlier this year requiring the full submersion of battery packs in water tanks, said Cory Wilson, a captain at the Fremont Fire Department. “We’ve had several incidents there,” he said.
Tesla has donated hundreds of vehicles to the local fire department for use in deconstructive demonstrations of the Jaws of Life and other rescue tools. “We’ve cut up 400 to 500 Teslas over the past five years,” said Wilson.
The Fremont Fire Department now has about 50 Teslas ready for the next of its regular two-day classes attended by emergency personnel from around the country. Visiting crews are taught how to safely cut through and demobilize the electric vehicles. Wilson said he accepted an invitation on behalf of the department to teach a special session in The Hague, Netherlands, for Dutch and German first responders in 2017.
“Not knowing how to secure an electric vehicle can be lethal,” he said. “We’re fortunate enough to have Tesla in our community.”
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