Something’s burning – how serious a risk are vehicle fires?

The switch to battery cars brings new challenges for dealing with car fires

"It's the stuff of nightmares: seeing smoke or flames appear as you're secured inside a moving vehicle," says Lauren Beehan of A Ireland. "Thankfully, it's not very likely."

Not very likely, but still possible and we all know the old scout’s motto of being prepared. According to Beehan, fire brigades across Ireland responded to 2,300 vehicle fires in 2019. Given that there are about two million cars on Irish roads, that’s about a 1 per cent chance – so it’s a small chance, but certainly not an impossibility that at some stage you will have to deal with a fire involving your car.

"Not all of these turn into fully fledged fires; some of them are stopped quickly and others turn out to be false alarms," says Beehan. "A Dublin Fire Brigade spokesman told us that quite often steam from car's radiator or dust from the safety air bags can be mistaken for smoke. That said, better safe than sorry – you should treat any steam or smoke as a potential fire until you've confirmed it's not."

Statistically, according to a long-term study carried out in the US between 2013 and 2017, a “mechanical issue” is the most likely cause for a vehicle fire, while a collision-related fire represents only a tiny fraction of such incidents – just 4 per cent. Cars are designed to withstand impacts, and their fuel systems especially so. Still, there are concerning figures within the figures – according to the US research, two-thirds of deaths associated with vehicle fires occurred when there was a collision.


It’s a slightly different picture on this side of the Atlantic – data from the UK shows that half of all vehicle fires between 2015 and 2020 were started deliberately. While somewhat sinister – there are cases of vehicle fires being started by criminals intent on stealing and cloning the identity of a car – that should bring some sort of relief as it means it’s relatively rare for a random mechanical issue to start a fire as you’re driving.

Get out

What should you do if the unthinkable does happen? Stop the car and get out, says Beehan. “Stop, pull in to a safe place if possible, and get all passengers out of the vehicle as quickly as you can and call the emergency services. You don’t want to delay leaving the vehicle. If it’s safe, you could use an extinguisher to tackle a small external fire, but don’t put yourself at risk – as the Dublin Fire Brigade reminded us – a car can be replaced, you can’t.”

Once you’re out, get behind a crash barrier (if there is one) and stay well away from the vehicle. That goes double if it’s an electric car you’re driving. While electric cars are obviously at a lower overall fire risk than conventional cars – they’re not carrying around a 60-litre tank full of highly flammable liquid, for example – lithium-ion batteries can catch fire if they become overheated or damaged, and the “thermal runaway” that then happens can be exceptionally dangerous.

Part of the problem is that burning batteries are exceptionally difficult to extinguish, and not just because using water on them is not a great plan. They can reignite even when the initial fire has been stopped, and then there’s the issue of the gases emitted by burning batteries.

According to Prof Paul Christensen of Newcastle University, one of the world’s leading experts on lithium-ion battery design: “The vented vapour represents a clear hazard in terms of its toxicity and the possibility of explosion, and the fumes from burning [batteries] also represent a toxic hazard.” The chief culprit here is lithium hexafluorophosphate, a chemical that makes up part of the liquid electrolyte of the battery. When it burns, hydrogen fluoride gas is released, which, according to the scientific journal Nature, “can pose a serious toxic threat, especially for large lithium-ion batteries and in confined environments”.

One potential solution is a fire blanket. These are not the small domestic devices that you might keep next to a chip-pan, but a huge 6sq m blanket, impregnated with quartz, which weighs about 30kg. Developed by Bridgehill, the blanket can put out a racing electric vehicle fire – burning at a temperature of more than 1,000 degrees – in as little as 15 minutes.

EV battery fires

It’s worth pointing out at this stage that although there are difficulties in dealing with EV battery fires – the voltage, the gases, the potential for reignition – the fact is that they are thankfully very rare, and their overall risk, at a societal level, is far lower than that of the damage to health caused by emissions from internal combustion-engine vehicles.

Nonetheless, battery fires have caused enough concern in the US that the National Transportation Safety Board has castigated car makers for not providing emergency services with enough information on how to deal with their vehicles. “Most manufacturers’ emergency response guides for fighting high-voltage lithium-ion battery fires lack necessary, vehicle-specific details on suppressing the fires” said an NTSB spokesperson. “In addition to hampering efficient extinguishing of high-voltage lithium-ion battery fires, the lack of clear, vehicle-specific firefighting information can lead to confusion or inadvisable action on the part of first responders.” One fire involving a Tesla (yes; the one where the owner crashed while sitting in the passenger seat and letting the so-called autopilot system drive the car unsupervised) took hours and more than 100,000-litres of water to extinguish.

Basically, we’re in a learning process. Over the past one-and-a-third centuries of dealing with petroleum-fuelled vehicle fires, we’ve become pretty well versed in what to do, both personally and in terms of how the emergency services react. Dealing with EVs – even though the overall risk is lower – is a new ball game, and emergency services are still playing catch-up.

In the meantime, the AA’s advice to Irish drivers is not to practise emergency exits from your vehicle, nor even to fit a fire extinguisher, but simply to take proper care of your car. “Keeping on top of your vehicle’s maintenance and getting it serviced regularly is the best way to avoid a spontaneous fire,” says Beehan.

“Given that around two in three roadside fires are caused by mechanical or electric faults, you should never ignore a warning light on your dashboard, and if your vehicle is ever part of a product recall, don’t wait to send it back. You might be avoiding some short-term inconvenience, but it could result in a much larger problem or even serious injury if a fire broke out. In Ireland, you can keep an eye on the Competition and Consumer Protection Commission’s website for recall notices, and check in with your manufacturer’s website every so often.

“The older your vehicle is, the more important it is to keep on top of your maintenance. In the US, roughly three-quarters of the fires attributed to faults in 2017 involved cars that were 10 years old or more, and some faults develop over time, rather than suddenly, especially if caused by fraying electrical wires or insulation, or rubbing of fuel lines.”