The Truth About Electric Car Safety

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Worried that an electric car might explode after a collision? In fact, after extensive crash testing like the side-impact test pictured here, the Chevy Volt and Nissan Leaf were awarded five stars and high safety ratings for rollover protection and front, rear and side collisions.
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National Highway Traffic Safety Administration chief David Strickland, left, is greeted on Capitol Hill in Washington, Wednesday, Jan. 25, 2012, by Rep. Jim Jordan, R-Ohio, prior to testifying before the House Regulatory Affairs, Stimulus Oversight and Government Spending subcommittee hearing on the safety of the all-electric car, the Chevy Volt.
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General Motors CEO Dan Akerson is sworn in on Capitol Hill in Washington, Wednesday, Jan. 25, 2012, prior to testifying before the House Regulatory Affairs, Stimulus Oversight and Government Spending subcommittee hearing entitled, "Volt Vehicle Fire: What did NHTSA Know and When Did They Know It?"
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The electric Leaf and Volt both earned 5-star crash safety ratings.
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This Friday, March 25, 2011 photo shows James Brazell as he poses with a charging unit for his Chevy Volt electric car at his home in Asheville, N.C. Brazell plugs the car in after short trips. "Pretty much I top it up every time I bring it into the garage," he said.
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A Nissan Leaf electric car is plugged into a charging station at the Seward Park Co-op apartments on the Lower East Side of Manhattan May 6, 2011 in New York. Connect by Hertz unveiled its first rental electric car and charging station in New York City where customers can rent this car by the hour.
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Experts say cars carrying batteries are safer than cars carrying gas tanks.
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One gallon of gas has the explosive power of 30 sticks of dynamite, but it's generally not perceived as dangerous.
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At this point, most Americans have internalized the precautions necessary for safety around gas-powered vehicles.

In November 2011, the extended-range electric Chevrolet Volt was beginning a modest sales climb when it was temporarily derailed by a report from Washington, D.C. A Volt had caught fire after a government crash test, which led to an official safety agency investigation. The fire occurred three weeks after the crash test, which damaged the battery, and could easily have been avoided if appropriate post-collision safety precautions had been followed.

According to Clarence Ditlow, executive director of the Center for Auto Safety, an electric car’s battery could potentially catch on fire if it heats to the point that it ignites flammable liquids near the battery. Draining fluids and removing gas tanks is common at junkyards and garages following real-life car accidents, but is not necessary in the case of gasoline-powered test crashes, because the testers use expensive, non-flammable Stoddard fuel, which poses no fire risk.

General Motors had actually developed procedures for draining and discarding the Volt’s battery pack following a crash, but according to company spokesman Greg Martin, GM hadn’t communicated them to the testing agency, the National Highway Traffic Safety Administration (NHTSA), at the time of the test. The Chevy Volt fire received a great deal of publicity, and raised a key question for potential buyers of electric cars: Are electric cars safe?

The public was suddenly unsure, especially after the Volt fire was hit by politically motivated attacks. “Move over, Solyndra,” wrote Greenwire, an environmental news service. “Conservatives opposed to the Obama administration’s spending on clean energy have a new whipping boy. The electric Chevrolet Volt is the new focus of angry conservative blog posts, testy congressional hearings and joking videos.” In December, Mitt Romney said the Volt is “an idea whose time has not come,” and the car was derided by some commentators as “Obama’s car.” The inconvenient truth here is that the Volt was launched in 2007 with George W. Bush in the White House, and the $7,500 federal tax credit that helps people buy it was also passed on Bush’s watch, in 2008. Even the first stages of the GM and Chrysler bailouts happened before Obama took office.

The facts surrounding the Volt fire are complex, and at least partly because of the sensationalist coverage, some people were left with the impression that the Volt has a record of exploding on impact, when in fact this has never occurred.

Volt sales took a hit, dropping to 603 in January from 1,529 in its peak month (December 2011) as of our press time. A survey of 3,800 Americans in December 2011 found a drop in interested “early adopters.” The percentage of respondents “very likely” to consider a Volt fell from 21.3 to 11.6 percent, and those “likely” to consider one dropped from 38.1 to 24.7 percent.

Yet NHTSA fully exonerated the Volt in late January following an investigation and a voluntary GM recall to strengthen the car’s battery protection. NHTSA found “no discernible defect trend,” and reported that it was not able to replicate the fire “either in full-scale vehicle testing or battery component testing.” They knew of no “real-world crashes that have resulted in a battery-related fire involving the Chevy Volt or any other electric vehicle.” (Read the Chevrolet Volt Battery Incident Overview Report for more information.)

Redundant Car Safety Systems

The truth is, manufacturers have gone to great lengths to ensure that their battery and plug-in hybrid cars are safe and have been equipped with numerous safeguards to avoid fire and exposing their occupants to high-voltage electricity. But there is no extensive paper trail on electric car safety simply because there haven’t been many electric cars on the road. According to Nancy Schwartz, an administrator at the National Fire Protection Association (NFPA), there is no database of statistical information on electric car fires.

NFPA does maintain extensive records on car fires generally, and reported that between 2003 and 2007 there were an average of 287,000 such incidents every year, measured by those requiring fire department intervention. In each of the years studied, car fires killed approximately 480 people, injured 1,525, and caused $1.3 billion in property damage. Given the 246 million vehicles on the road in the United States, this translates into one car fire annually for every 1,000 vehicles — making auto fires a fairly familiar feature of the American landscape. “After all, it’s not called the internal-combustion engine for nothing,” wrote Bryan Walsh of Time in a blog post that concluded that electric cars might be safer than gas-only vehicles.

The risk of being shocked by touching your car or truck is also low in electric cars, because the electrical system “floats” in isolation from the chassis. Many electrical subsystems are designed to shut off if they detect a current path to the car’s chassis. Electric cars also have safety disconnects designed to cut power in the event of a collision, short circuit or other danger.

Safety devices such as these are one reason both the Volt and the all-electric Nissan Leaf received top ratings from NHTSA and the Insurance Institute for Highway Safety (IIHS).

According to Sebastian Blanco, lead blogger at the clean car website AutoblogGreen: “I don’t think EVs are any more inherently dangerous than gas vehicles. In fact, a battery pack is safer than a tank of gasoline, even if li-ion cells can still catch fire under certain unusual circumstances. Automakers will continue to make safety a priority, being careful to isolate the cells and the energy in them in the event of a crash. Hundreds of thousands of safe miles have been put onto plug-in vehicles, so people should be willing to trust them, recognizing, of course, that a motor vehicle is always potentially dangerous.”

Brian Wynne, president of the Electric Drive Transportation Association (EDTA), echoes Blanco. “I don’t think anyone educating themselves about these cars should have any concerns about their safety,” he says. “They go through the exact same safety tests as any other vehicles.”

Wynne characterized GM’s repair for the Volt as a redundant “belt-and-suspenders fix, an extremely appropriate response from the company.” He says the EDTA supported the NHTSA investigation, because the industry wanted to reconfirm the safety of electric cars for the public.

5 Stars for Electric Car Safety

Cars with plugs have received stellar safety ratings. The Volt and the Leaf both received five-star overall ratings from NHTSA and were awarded top safety ratings for front, rear, side and rollover protection from IIHS. (Learn more: Volt NHTSA ratings; Leaf NHTSA ratings; Volt IIHS ratings; Leaf IIHS ratings.)

NHTSA is trying to get the word out that its investigation is over and electric cars were acquitted. NHTSA administrator David Strickland says, “NHTSA continues to believe that electric vehicles show great promise as a safe and fuel-efficient option for American drivers. Based on the available data, NHTSA does not believe that Volts, or other electric vehicles, pose a greater risk of fire than gasoline-powered vehicles. In fact, all vehicles have some risk of fire in the event of a serious crash.”

Ditlow does not think the electric car’s reputation has been irreparably harmed by the investigation. He says the cars are now built to a high standard of crash-worthiness (unlike 1970s electrics such as the golf cart-based CitiCar), and many internal-combustion vehicles present a worse fire safety record than the Chevy Volt does. “Typically, in an electric car fire you have time to get out of the vehicle,” he says. In gasoline cars, fires can spread quickly and, Ditlow says if there’s an immediate explosion, your chances of getting out are extremely slim.

Ditlow faults both NHTSA and GM for not having policies in place to routinely drain fluids from its electric and plug-in hybrid cars following a crash test. Several other gas car crash tests that caused fuel to be spilled led to NHTSA investigations, but had similarly not resulted in government-ordered recalls.

Use Caution: Electric Car Safety Measures

Following the Volt fire incident, NHTSA issued common-sense guidelines for consumers whose cars have high-voltage batteries.

Always assume:

  • The battery and associated components are fully charged.
  • Exposed electric components, wires and high-voltage batteries present potential shock hazards.
  • Venting/off-gassing battery vapors are potentially toxic and flammable.
  • Physical damage to the vehicle or battery may result in immediate or delayed release of toxic and/or flammable gases that can cause fire.

Some similar precautions apply to internal-combustion cars — don’t smoke while filling your car; don’t run the engine in an enclosed space — but most Americans have internalized them by now. In fact, a gallon of gasoline has the explosive power of 30 sticks of dynamite, but it’s generally not perceived as a dangerous substance.

The Volt’s — and by extension, the electric car’s — reputation may take time to recover, but it’s probably not too far gone. On January 25, GM CEO Dan Akerson told the House of Representatives Committee on Oversight and Government Reform that the Volt is safe.

Also that day, John German, a former Chrysler engineer who is now senior fellow and program director at the International Council on Clean Transportation, told investigators that lithium-ion batteries, shared by cars and computers, are capable of developing both high temperature and “thermal runaway.” He pointed to the recall of nearly 6 million Sony laptops because of a fire hazard due to flawed battery design.

But, German says, “Cars are not computers. Every auto manufacturer has worked to develop lithium-ion chemistries that are much more abuse-tolerant, as well as more durable and reliable. At least with respect to fire risk, electric vehicles are far safer than gasoline-fueled vehicles.” He added that overall electric car safety is determined not just by cell chemistries, but also by the effectiveness of built-in cooling systems, internal-pack construction, cell isolation and external packaging of the battery pack.

Worries About Exposure to Electromagnetic Fields

Another potential concern — in both hybrids and electric battery cars — is exposure to electromagnetic fields (EMFs). Because the cars carry high-voltage electricity, they represent a potential risk similar to that posed by proximity to high-voltage power lines. But there’s no conclusive proof that EMFs are dangerous, and there is a welter of conflicting scientific studies.

Consumer Reports tested a number of cars for EMF levels in a 2010 test and found, surprisingly enough, the highest reading in a non-hybrid Chevrolet Cobalt: 30 milligauss (the measure of a magnetic field), more than double the reading in the Chevrolet Tahoe Hybrid. Consumer Reports concluded that there is “no established threshold standard that says what an unhealthy dose might be, and no concrete, scientific proof that the sort of EMF produced by electric motors harms people in the first place. Taken together, the many studies of EMF radiation and human health are inconclusive.”

In 1999, the National Institute of Environmental Health Sciences (a division of the National Institutes of Health) reported to Congress that “the overall scientific evidence for human health risk from EMF exposure is weak. No consistent pattern of biological effects from exposure to EMF [has] emerged from laboratory studies with animals or with cells.”

Automakers take precautions to isolate drivers and passengers from EMF radiation and measure exposure with professional gauss meters that can cost thousands of dollars. Honda spokesperson Chris Martin says the company’s tests of its hybrid cars had results that were well below the International Commission on Non-Ionizing Radiation Protection standard. He cautioned against consumers taking matters into their own hands through the use of inexpensive hand-held scanners to test for EMFs. “People have a valid concern, but they’re measuring radiation using the wrong devices,” he says.

Nevertheless, crafty entrepreneurs are eager to sell concerned motorists such devices as the $15.50 “Crystal Catalyst Bead,” worn as a necklace for “personal EMF protection and continuous energy enhancement.” The much pricier “Nova Scalar Resonator Ankle Bracelet” ($349) is for “primary and wireless EMF protection.” These devices are about as effective as a CD hung from the rearview mirror to deter police radar.

An approach with more scientific validity is to install shielding on locations of the car close to EMF sources. The shielding is similar to that used to protect patients from fields generated by MRI machines. It’s an expensive option, however, and has not been proven necessary in automotive applications.

First Responders

Electric cars will compile a much better safety record if emergency personnel know how best to keep them safe after an accident. NFPA launched a partnership with GM and OnStar to train first responders in responding to incidents involving the Volt in 2010, before the car was actually on the ground. The program includes a series of videos and course material, and includes an extraction demonstration using an actual Volt. Key points covered are powering down the 360-volt system (cables to be cut are clearly marked with first-responder tags, and there is also a manual service disconnect device), fighting a battery fire with water and getting people safely out of the car.

At the Firehouse Expo 2011 electric car safety symposium in Baltimore, Ron Moore, a Texas-based firefighter and extrication expert, told an audience of first responders that the Volt has two electrical systems, only one of which carries high voltage, and that both must be disconnected following a crash. A professional should also drain the car’s fluids, including its battery coolant. Because the Volt and Leaf battery packs are located underneath the car, “cribbing” (stabilizing a post-accident car with wooden blocks) can cause damage and is not recommended, he said.

Made Safe the First Time

The Volt fire damaged the car’s reputation and that of all battery-powered vehicles, but in fact the cars have an unblemished safety record when proper procedures are followed. The good news is that all of the plug-in cars on the market today have received top marks from both government and independent testing agencies. “Safety first” is more than a slogan when it comes to electric car engineering, and NHTSA has publicly recognized that. When it closed the case on the Volt fire, the agency concluded that it “does not believe that Chevy Volts or other electric vehicles pose a greater risk of fire than gasoline-powered vehicles.”

Jim Motavalli is a contributor to the New York Times, NPR’s Car Talk and Mother Nature Network. He is author of High Voltage: The Fast Track to Plug in the Auto Industry.