Last Update: July 25, 2015

In May 2011 the NHTSA crash tested a Chevy Volt. Three weeks later it caught fire while in a storage lot. In November 2011 the news was released to the public. Following this a politically motivated firestorm erupted.

The political firestorm almost entirely exaggerated the actual danger to the point of committing actual lies. Generally those doing the exaggeration were extreme right wingers who are collectively also committed to destroying President Obama's administration and re-election chances in 2012. For example, one of the lies is to claim that President Obama pushed for the Chevy Volt, calling the Volt Obama's baby. However the truth is that the Volt project was launched in 2006 by GM, wholly by GM's choice, with no pushing by the government.

For the record, this is the Volt which burned and touched off the whole story.

Known probable cause of the fire

The NHTSA final report contains a detailed explanation of the forensic investigation, the series of crash tests, and reasoning leading to their conclusions. Which are ...

First, the cause of the fire was clearly due to a piece of metal intruding into the battery pack, poking a hole in the pack, breaking some of the battery cells, rupturing coolant lines, and causing short circuits. Over a period of weeks some kind of condition built up which resulted in the fire.

"The intrusion alone can cause cell damage, shorting of the battery pack negative bus bar, and battery coolant leakage." They demonstrated that the coolant is conductive at the high voltages present in the battery pack. The crash test procedure included a rollover that caused coolant to slosh around and exacerbate short circuits.

The windshield and rear view mirror were "dislocated" from the vehicle. That is, they were found on the ground well away from the vehicle. The manner of this indicates a "pre-fire pressure event" (a.k.a. explosion) they believe was due to cells venting electrolyte due to a thermal event (a.k.a. heat) in the battery pack.

The report states with certainty that the fire started in the Volt. It notes that several components were found well away from the car, undamaged by fire. The report goes on to talk about a "high-pressure event" (a.k.a. explosion) that had to have preceded the fire, and it was the high pressure event that would have caused these components to be flung from the Volt.

At least seven areas between the passenger cabin and battery tunnel were breached during the crash test. These holes were produced by arcing due to battery cells shorting to the car body. The arcing was due to structural metal bands that run around the cells becoming positively charged during the fire. In other words, something in the pack shorted to the metal bands.

The NHTSA was never able to directly replicate the fire despite several crash tests. They did sort of replicate a fire in a condition that was similar to the crash test, and it was then that they opened the investigation.

As a general observation - as the temperature around a lithium-ion battery cell rises, electrolytes and organics begin to vaporize within the cell. This increases the pressure inside the cell. The LG P1 cells in the Volt battery pack are pouch style cells, meaning they're enclosed in a plastic/foil pouch. In pouch cells the gasses vent out the top of the cell, because its the structurally weakest part of the pouch. In the Volt battery pack, this is the only part of the cell not supported by other components.

The vented gasses are flammable and easily ignitable.

The report thinks the likely specific source of the fire is physical damage to cells 198-204 in the battery pack, the damage causing an internal short inside the cells, resulting in conditions that eventually released electrolyte vapors, causing the fire.

Another possibility is the VSTM boards at the top of the pack. These were exposed to coolant that could have left a conductive carbon film on the electronics. This could have caused an internal short.

The Chevy Volt as a Political Punching Bag

Some right wing (Republican) naysayers had been focusing ire on the Chevy Volt as part of their vilification of the Obama Administration green jobs green technology vision. We've seen these people destroy many projects or people over the years. Their dander gets up about something, and they all gather around that thing making up any story they can think of, even totally false fabricated stories, all in an effort to create a negative taint they can paint on their target, and repeat that negative taint on every opportunity. An example? One prominent example is how they destroyed Al Gore's reputation by creating false stories such as claiming he claimed to have invented the Internet. Truth is he never made any such claim, and at the same time in the late 1980's as a Senator he did critical political work to expand the Internet (specifically the NREN expansion) that was later a critical part of the commercialization of the Internet a few years later.

A discussion of the political attacks against the Chevy Volt is on the blog (see ( An example of the sort of attack was a rant by Rush Limbaugh in December (see Regime Covered Up Chevy Volt Dangers) which was full of inaccuracies, exaggerations, and more. Limbaugh has been attacking the Volt with lies (see ( Rush Limbaugh shows clueless idiocy about electric cars) for a long time so there is nothing new about him doing so now.

The timeline below lists a number of articles from Chevy Volt naysayers and defenders alike. Here are some of the points the naysayers have made:

  • Chevy Volt crash test fire proves it's a dangerous car As we see below, there was only one fire in a complete Volt during crash tests, and two fires in battery packs when tested in isolation. In each case the fire took 1-3 weeks to develop. This is far less dangerous than a gasoline powered vehicle which are so dangerous they routinely burst into flames.
  • "government incompetence when interfering with the free market" GM began the Volt project long before the Government bailed out GM, taking an ownership stake in GM. The government reportedly fought to cancel the Volt project, but Bob Lutz and the GM board fought to keep it going. GM's bankruptcy actually reflects negatively on GM's management but somehow these naysayers have made it into Obama's negative baggage because of the bailout.
  • $250,000 per car in subsidies ..bogus..


A lot of the information below comes from the NHTSA final report (PDF)

Table of crash tests

Date Test Program Test Type Battery Intrusion Coolant Leakage Fire Test Number
April 20, 2011 Compliance Side Pole Yes, minor cell damage No No 7358
May 6, 2011 NCAP Side - Moving Deformable Barrier No No No 7392
May 11, 2011 NCAP Frontal No No No 7393
May 12, 2011 NCAP Side Pole Yes Yes Yes 7394
Sept 21, 2011 Compliance Side Pole No No No 7454
Dec 22, 2011 Compliance Side Pole No No No ??

The reports can be found at (

April 18 2011: A garage fire involving a Volt in Connecticut creates out-sized controversy

A Volt owner in Connecticut had his garage burn down while the Volt was parked inside. Initially there was bashing because of this fire, but later evidence showed up that the Volt owner was at fault because of his other electric car - a home EV conversion. see: (

By May 18, the Volt was cleared from being at fault, by the Fire Marshall. see: (

However it appears the Volt that had been in the fire re-ignited itself a week after the fire. This is curious given the delayed ignition of the Volt battery pack documented on this page. see: (

April 26 2011: Insurance Institute for Highway Safety (IIHS) announces five-star crashworthiness of both Chevy Volt and Nissan Leaf

Insurance Institute for Highway Safety (IIHS) announced that both the Volt and Leaf got top ratings in their tests. see: (

May 2011: NHTSA crash test

On May 12, 2011 the NHTSA conducted a NCAP side-pole crash test of the Chevy Volt at a test facility in Washington. The facility is owned and operated by NHTSA Contractor, MGA Research. Based on its performance the Volt received an NHTSA five-star crash-safety rating for both frontal and side-impact crash-worthiness and occupant protection.

June 4-6 2011: Volt catches fire in storage

On Monday June 6, 2011, personnel at MGA Research notified the NHTSA that a fire had occurred over the previous weekend. The fire involved four vehicles total, one of which was the Chevy Volt. The vehicles were in a storage facility which, as you can see, was more-or-less a road next to a grassy field.

Local fire authorities conducted an initial fire investigation, initially focusing on a possible arson.

The NHTSA contacted Hughes Associates, a battery and fire expert, to investigate the cause of the fire. Their initial forensic investigation took place June 13-14, 2011 at MGA Research's facility. The report was available in July 2011, showing the fire probably originated in the Chevy Volt.

As you can see, a group of vehicles all caught fire. They were:

  • 2006 Ford F150
  • 2011 Lexus RX350
  • 2011 Chevrolet Volt
  • 2011 Dodge Charger
  • 1995 Chevrolet Z71 (this vehicle belonged to an employee and happened to have been stored there)

The F150, the Lexus and the Volt were parked front-to-back in a line, and the Charger was parked so its nose faced the nose of the Volt. The vehicles had a minimum of ignitable fluids and most of the 12v batteries were disconnected. The Chevy Volt battery pack was disconnected at the Manual Service Disconnect.

The only remaining source of fire was electrical energy in the battery packs, especially the big pack in the Volt.

June 6 2011: NHTSA announces the Volt receives 5-star crashworthiness rating

On June 6 the NHTSA announced results of the crash testing they'd just done, awarding the car a 5-star crashworthiness rating. see: (

This is a rich coincidence, is it not? The same day MGA Research found the smoldering Volt on their storage lot the NHTSA announces a perfect crashworthiness rating. But as noted above, nobody knew on June 6 what was the cause of this fire.

June 21 2011: NHTSA announces a project to study fire hazards in electric vehicles

"... the U.S. National Highway Traffic Safety Administration (NHTSA) announced an $8.75 million study to investigate whether lithium ion batteries in electric vehicles pose a potential fire hazard. NHTSA is undertaking the study to ensure the safe charging of vehicles and to mitigate any potential risks. No prior vehicle incident triggered the study." see: (

I was unable to find a matching NHTSA press release, only this note on a blog run by the National Fire Protection Association. By June 21 the NHTSA clearly knew about the Volt fire and as we see in the surrounding events in this timeline had a forensic study well underway.

June 2011: Begin monitoring all Chevy Volt crashes

The NHTSA Special Crash Investigation Division and GM began monitoring all crashes involving Chevy Volt's. These included some severely damaged vehicles. No fires.

Additionally NHTSA investigated two incidents where Chevy Volt's were in garage fires. In each case the Volts were parked in a garage that caught fire. In both cases it was determined the Volt's were not the source of the fire.

June 2011: Crash tested Volt shipped to Ohio

The Volt in question was shipped to the NHTSA's Vehicle Research and Test Center (VRTC) in East Liberty, Ohio. Hughes Associates, NHTSA and GM engineers conducted a vehicle teardown.

Inspection revealed that a "transverse stiffener" that's normally beneath the drivers seat had penetrated the tunnel into the battery pack, damaged cells in the battery, and ruptured the coolant system.

Battery pack disassembly occurred on June 20-23, 2011.

September 11, 2011: A bad Chevy Volt wreck happened on the NJ Turnpike - no fire

A Chevy Volt owner in New Jersey got into a really bad wreck. They felt it was miraculous that they escaped that horrible wreck with very little or no damage to their bodies. This validates the five-star crashworthiness rating the Volt achieved. It's also noteworthy that despite the horrible wreck, there was no fire. see: (

September 2011: Another Chevy Volt crash tested by NHTSA

The NHTSA performed another crash test at MGA Research's facility. By this time they will have had a fairly good idea of the cause of the fire, and clearly wanted to see if the fire could be replicated. They outfitted the test vehicle with additional cameras and data collection devices. The crash test did not result in the battery pack being penetrated, no coolant leakage, and no fire following the crash test.

September 2011: White House informed of fire

"Strickland said last week the White House was informed in September of the June fire, but officials didn't ask the agency to keep the information secret." (see: ( David Strickland, heads the National Highway Traffic Safety Administration. And that NHTSA said it rarely opens an investigation after just one incident. "Because the Volt incident involved a potential risk in newly emerging technology, NHTSA proceeded to open this investigation based only upon the results of limited test data and without waiting for data from real-world incidents." (see:

Summer & Fall 2011: NHTSA, Dept of Energy, Dept of Defense work on ways to test Chevy Volt battery pack

Having determined the battery pack in the Volt was the likely cause of the fire, the investigators turned to developing a way to test the pack, so they could verify their theory of the cause of the fire. This test would be of just the battery pack in isolation from a car. It would create the same impact and rollover scenario, but just with the battery pack.

Nov 6 2011: North Carolina Fire officials and Duke Energy call on Volt owners to suspend using charging stations following a garage fire

Another garage fire that involved a Chevy Volt. In that fire the Volt was eventually cleared as being responsible for causing the fire. This didn't stop naysayers from pouncing on this as proof of dangers from the Volt. And the NC Fire Officials and Duke Energy should be seen as over-reacting when they called on suspension of charging station use. (see: (

This case has eerie connections to a set of EV1 fires during the EV1 time period. In those cases a few EV1's caught fire while being charged, and it was discovered that a design flaw in the EV1 caused the fire. GM performed a recall of the EV1's, keeping them for months before implementing a fix and returning cars to lease-holders.

Nov 2011: Work with National Fire Protection Association

Began working with the National Fire Protection Association to identify all vehicles with lithium-ion batteries on-board and develop appropriate steps for handling these vehicles after crashes.

Nov 12 2011: Bloomberg News and NHTSA reveal news

Mid-Nov 2011: Crash test of the battery packs

The NHTSA, using the previously developed procedure, tested a total of six battery packs at General Testing Laboratories (GTL). Some of the tests were in mid-November, the others in early-December.

Testing of the coolant had shown it was conductive at high voltages, and therefore that the coolant could cause electrical shorts.

There were two sets of tests

In one set, the packs were impacted and then rotated through a full 360 degrees just as in the car crash tests. Battery coolant system was intentionally ruptured to be sure the circuits were wetted by coolant.

Another set of tests were meant to test the effects of cell damage, and of a bus bar being shorted to the chassis. These tests were performed in mid-December.

Test# Date Impact Rotation through 360 degrees Bus Bar Grounding Observations
1 mid-Nov Yes Yes unknown Battery pack destroyed during 11/24 fire initiated by test#2 battery
2 mid-Nov Yes Yes unknown Battery pack caught fire on 11/24 (module 3) one week after the impact test
3 mid-Nov Yes Yes Yes Sparks and flames jetted from pack when at 180 degree position. Pack disassembled on Nov 21
4 early-Dec No Yes No Discolored wires indicating battery heating; no fire
5 early-Dec No Yes Yes Rapid electrolysis at 180 and 270 degree positions, battery pack caught fire on 12-12 (6 days after test)
6 early-Dec Yes No unknown Slow discharge of one cell group

November 25 2011: NHTSA Opens formal investigation

Having replicated the fire (proving there's some level of actual risk) the NHTSA opened a formal investigation (PE 11-307). The NHTSA says they rarely open a formal investigation when there are no real-world examples of a risk. Obviously they were reacting to the level of controversy that was building (in part) but also in part being cognizant of the newness of electric drive trains. The NHTSA report says "NHTSA sought to ensure the safety of the driving public with emerging EV technology." (see: (

Dec 2 2011: GM offers to buy back Volt's from worried customers

Initially GM offered to provide loaner vehicles to worried customers, but later stepped it up to offer buying back Volt's. This is either an example of great customer service, or an admission of guilt, depending on how you look at it. (see: Chevy Volt battery fires news roundup - Dec 5, 2011 (

GM: Buybacks a "last resort" for Chevy Volts: (Dec 1, 2011) Says that GM is considering buying back Volts as a last resort, but that the first steps are to talk with any concerned Volt owners and provide loaner cars. GM will recall all Volts if necessary based on results of the investigation.

GM offers to buy back Chevrolet Volts after crash tests show fire risk: (Dec 1, 2011) AP news report quoting GM CEO saying they're willing to buy back Volts and also conduct a recall.

Today's Volt Update: GM Buyback, Owners Rally, Sales Goal Unmet: (Dec 2, 2011) Refers to the AP news item saying GM CEO offers to buy back Volt's or offer loaner cars. GM spokesperson admits they're unlikely to make the 10,000 sales goal. Beginning steps of Volt owners rallying to write an open letter to GM.

December 7 2011: Letter to NHTSA from House Oversight Committee

Rep's Issa, Jordon and Kelly demanded a whole slew of information from the NHTSA around when they told various stakeholders of the Chevy Volt battery pack fire, and why did the NHTSA delay disclosure. (see: ( The hearing by the committee's panel on Regulatory Affairs, Stimulus Oversight and Government Spending will include a look at the government's investigation into fire risks. (see: Rep Issa apparently plans a new witch-hunt hearing on the Chevy Volt in January)

U.S. Transportation Secretary Ray LaHood reiterated "Chevy Volt owners can be confident their cars are safe to drive." LaHood rejected the suggestion Thursday that regulators kept information about safety concerns regarding the Volt from Congress, saying it was "absolutely not true." NHTSA said it had waited because it was gathering information on the incident, which occurred three weeks after a crash in which a Volt's battery compartment was seriously damaged. (see: (

December 7 2011: NHTSA buys Volt's for further study, several reports that fix will be available soon

Reports surfaced in several news sites that the NHTSA had bought some Volt's for further study, and that a fix was close to being finalized. (see: ( NHTSA buying Volt's for study, rumors of Volt fix a few weeks away, and officials claiming the Volt is safe)

Reports at this time described the following fixes, and are rather close to the fixes actually performed:-

  • Laminating the circuitry inside the battery pack (presumably this means some kind of conformal coating, or other kind of circuit protection layer)
  • Changes on coolant changes to eliminate leaks
  • Reinforcing the battery pack case

December 12 2011: Chevy Volt Battery fires threaten adoption of electric vehicles (Forbes)

Using no evidence a writer in Forbes claims that the Chevy Volt battery fire controversy is making people afraid of the Volt, afraid of electric cars in general, and harming sales of such vehicles. (see: (

If there were proof of this sort of effect that would be one thing. But to claim this while having no such proof is yet another thing. It makes one wonder whether this Forbes writer is a propagandist.

December 12 2011: Ford and Nissan respond to Volt fire controversy

Ford uses battery cells from LG Chem, the same source as the cells in the Chevy Volt. Nissan uses battery cells of their own design. Both released statements about the fire controversy, possibly because they recognize the taint being painted on the Chevy Volt might also rub off on their electrified vehicles. (see: (

No post-crash fires occurred in the Nissan Leaf. Further the Leaf battery pack is fully encased in steel. We should note that the vulnerability in the Volt pack was partly due to intrusion of an object into the pack, damaging some cells, and partly due to bus bars in the battery pack grounding to metal in the battery pack. The steel encasing in Nissan's battery pack runs the risk of similar grounding of bus bars against that steel case.

Ford's response was "We still have limited information about the cause of the Volt fires in the government crash tests, so it is difficult to comment on how they relate to Ford�s electrification program. We will continue to work with the NHTSA as we prepare to launch our electrified vehicles over the next year.�

December 13 2011: GM delays manufacturing of Opel Ampera for safety concerns

The Opel Ampera is the European version of the Chevy Volt. It's to be built in the same Hamtrack factory where the Volt is built, and is largely the same car. As should be obvious, the Ampera would have the same vulnerabilities as the Volt, and the same safety fix would apply to the Ampera. The plant is not producing Ampera's or Volt's until the fix is fully implemented at the factory. (see: (

December 16 2011: Frank Beckman says "Time to unplug Volt hysteria"

Frank Beckman appears to be a prominent Detroit area media personality. He's also firmly in the Conservative/Republican camp. He published in the Detroit News an op-ed complaining about the level of animosity being aimed at the Chevy Volt by his fellow conservatives. (see: ( According to Beckman it's time to stop the hysteria because it's completely misguided. His piece goes step-by-step through the points being raised by naysayers, demolishing each of them. It's an excellent piece.

December 20 2011: GM's Akerson claims they'll build 60,000 Volt's in 2012, later recanted

In an interview Dan Akerson (GM's CEO) said they'll build 60,000 Volt's in 2012. (see ( and He apparently was talking about factory capacity to manufacture the car. A few weeks later he was quoted saying that GM will adjust the number manufactured to meet actual demand, obviously so that GM doesn't get into an oversupply condition with the Chevy Volt. But that latter statement has been taken by the naysayers as questioning whether GM is planning to back away from the Volt.

December 20ish 2011: Mackinac Center makes bogus study about Chevy Volt subsidy

The Mackinac Center for Public Policy posted a statement claiming that each Chevy Volt is subsidized to the tune of $250,000 or more. They arrived at this figure through a bogus line of reasoning involving adding together all the grants given to several companies, and dividing by the number of Volts sold in 2011. This ignores the fact that the factories built as a result of the subsidies will be used over a 20+ year period, hence its inappropriate to calculate the subsidy this way. (see: ( An article on took apart the Mackinac Center reasoning very well. (see: (

December 22 2011: Chevy Volt crash test w/ fix

GM had proposed a field fix (to stiffen the battery box). The NHTSA observed the installation of the fix into a Chevy Volt which they shipped to MGA Research in Wisconsin.

On Dec 22, a side-pole crash test was run. The vehicle was monitored for three weeks. There was no intrusion into the battery pack, no coolant leakage, and no fire.

December 25ish 2011: A123 and Fisker reveals battery pack flaw and recall

On Christmas Eve A123 Systems and Fisker revealed they'd found a battery pack flaw that could cause fires. (see: ( They initiated a recall to fix the problem (a hose clamp improperly installed). (see: The recall was finished by mid-January 2012.

Jan 5 2012: GM agrees to fix, NHTSA concurs

GM and the NHTSA made joint announcements that they'd developed a fix for the battery pack flaw, based on preliminary results of their research. The fix strengthened part of the battery pack, because they'd discovered the side impact poked through the pack breaking some coolant hoses. (see: (

Statement of National Highway Traffic Safety Administration On General Motors' Plan to Address Potential Fire Risk in Chevy Volts (see: (

GM Announces Enhancements to Chevrolet Volt (see: ( and

Jan 25 2012: Hearing before House Oversight and Government Reform Committee

The hearing is titled "Volt Vehicle Fire: What did NHTSA know and when did they know it?"

General Motors Chairman and CEO Dan Akerson agreed Wednesday to testify next week before a House panel investigating the government's handling of an investigation into fire risks in the Chevrolet Volt. (see: (

The Committee sent a letter to the NHTSA in December demanding answers to a laundry list of questions, which the NHTSA has not answered. Clearly this will be key part of the hearing. (see: (

During the hearing GM's CEO Dan Akerson opened his remarks saying that while the Volt was designed by GM's engineers to be an excellent car, it wasn't designed to be a political punching bag. (see: (

Garage & House fires where a Volt was in near proximity

During 2011 at least two garage fires occurred in which a Chevy Volt happened to be in the garage. In all cases the Volt was cleared of responsibility in causing these fires. The NHTSA report discusses and refers to each of these fires.

UPDATED: Who Knew a Single Garage Fire Could Spark So Much Electric Car Bashing? ( :- (April 18, 2011) A Volt owner in Connecticut had his garage burn down while the Volt was parked inside. Initially there was bashing because of this fire, but later evidence showed up that the Volt owner was at fault because of his other electric car - a home EV conversion.

Exclusive: Chevrolet Volt unofficially cleared in Connecticut garage fire: ( (May 18, 2011) The Volt was cleared from being at fault, by the Fire Marshall.

GM To Investigate Volt Blaze Re-Ignition: ( (April 18, 2011) It appears that the Volt in this incident re-ignited itself five days after the initial fire. Curious given the re-ignition of the crash tested Volts. Additionally it's clear here that the fire was caused by the car owner because of what he was doing with his home-built EV conversion.

After N.C. Fire, Duke Energy Advises Customers to Suspend Use of Electric Car Chargers: ( (Nov 6, 2011) A different house fire, in North Carolina. Again the fire officials weren't calling the Volt to be at fault in the fire, they're quoted saying the fire could have come from anything in the garage, but at the same time the local Utility called for customers to stop using the chargers.

House fire investigators say Chevy Volt charger not to blame in North Carolina blaze: ( House fire investigators say Chevy Volt charger not to blame in North Carolina blaze A side issue is a house fire that occurred in a garage in which a Volt was parked and plugged-in. "Garland Cloer, Iredell County�s chief deputy fire marshal, said it appears the fire did not start in the electric car. He wouldn�t say more about the fire�s origin, because investigators for several agencies and manufacturers are still examining the debris."

About the Author(s)

David Herron : David Herron is a writer and software engineer focusing on the wise use of technology. He is especially interested in clean energy technologies like solar power, wind power, and electric cars. David worked for nearly 30 years in Silicon Valley on software ranging from electronic mail systems, to video streaming, to the Java programming language, and has published several books on Node.js programming and electric vehicles.
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