CWU Issues EV Safe Driver Guidance to Protect Members Working in Electric Fleets

 

The Communication Workers Union has published new EV Safe Driver Guidance to help members across Openreach, BT and other fleet operations recognise battery-related risks and stay safe as electric vehicles become more common at work.

Electric vehicles are generally safe, and the guidance does not suggest otherwise. Fire experts point out that battery fires are less common in electric vehicles than in conventional combustion vehicles, and a 2023 Finnish study found EVs caught fire less often than petrol cars, mile for mile. But when a lithium-ion battery does fail, the consequences can be severe, and the guidance warns that dashboard alerts may not give early warning.

Know the risks
The guidance highlights battery damage after impacts, charging faults, overheating, degradation and the potential release of hazardous gases.

Drivers are urged to carry out routine pre-drive checks and watch for unusual smells, smoke, overheating, warning lights, fluid leaks or visible damage. If there are any concerns, they should not continue driving and should seek professional help.

What the research says
The guidance's concerns are backed by independent research:

• Toxic gases. Swedish research on lithium-ion battery fires found that the emission of toxic gases can be a larger threat than the heat. The tests measured hydrogen fluoride (HF) at between 20 and 200 mg per Wh of nominal battery energy capacity, plus a further 15 to 22 mg per Wh of phosphoryl fluoride.
• Gas hazards generally. A 2024 meta-analysis of thermal runaway gas studies found that some of the gases released, such as carbon monoxide and hydrogen fluoride, are poisonous.
• Fire behaviour. Fire tests on lithium-ion cells found that cells with a higher state of charge gave a higher heat release rate, and in one test a cell produced a hazardous projectile.
• Impact damage. Fire service specialists say thermal runaway is more likely in a high-energy impact, and battery condition also matters.
• Re-ignition. A battery fire that appears to be out can start again hours later in some cases. This is why the guidance says a vehicle showing signs of distress must be professionally assessed before reuse.
• Firefighting. According to insurer QBE, thermal runaway burns differently, takes much longer to tackle and can require up to 10 times more water to contain.

The UK picture
Freedom of Information data analysed by insurer QBE shows UK fire and rescue services attended 279 electric vehicle fires in 2025, up 133% from 120 in 2022. Over the same period, the number of electric vehicles on UK roads rose by 206%, from 664,148 to 1,971,764.

Across all lithium-ion batteries, including e-bikes, phones and power tools, brigades are tackling a fire every five hours.

Official fire statistics do not yet separate EV fires from other road vehicle fires, which makes accurate monitoring harder. QBE's advice is to check for battery damage after impacts or accidents.

Simple checks, clear limits
The guidance focuses on visual checks any driver can do safely without specialist training: fluid leaks, damaged panels, impacts to battery protection trays, charging port defects and signs of heat damage.

It is equally clear on what drivers must not do: inspect battery systems, touch high-voltage components or keep driving a vehicle showing potential warning signs.

Any EV showing signs of battery distress should be taken out of service immediately and professionally assessed before it is used again.

Spotting thermal runaway
Thermal runaway is a serious battery failure that can lead to fire, explosion or toxic gas release. Early warning signs include unusual chemical smells, unexpected heat, smoke, vapour, hissing noises and erratic vehicle behaviour.
If two or more of these signs occur together, drivers should stop immediately, leave the vehicle, move to a safe distance and call the emergency services, telling them the incident involves an electric vehicle battery.

Employer responsibilities
The guidance reminds employers of their legal duties under health and safety law. These include providing safe vehicles, suitable training, effective maintenance and clear emergency procedures, as well as keeping charging infrastructure safe and giving workers the information needed to recognise and report defects.
For CWU reps, it offers advice on recording incidents, investigating recurring faults, requesting maintenance records where concerns arise and making sure members receive proper EV safety briefings.

The key message
If an EV shows battery warnings, unusual heat, smoke, hissing, chemical smells or fluid leaks, or has suffered impact damage: stop using it, keep clear, do not charge it and seek professional assistance immediately.
CWU North Anglia welcomes the guidance and encourages all members who drive electric vehicles for work to read it and raise any concerns with their local CWU representative.

The full CWU EV Safe Driver Guidance is available to download as a PDF, from the Unionsafety E-Libary or by clicking on the image above right..

References

1. Larsson, F. et al. (2017). Toxic fluoride gas emissions from lithium-ion battery fires. Scientific Reports. Chalmers University of Technology / RISE.
2. Larsson, F., Andersson, P., Mellander, B-E. (2014). Battery Aspects on Fires in Electrified Vehicles. Fires in Vehicles (FIVE) 2014 Conference Proceedings, pp. 209–220.
3. Meta-analysis of lithium-ion thermal runaway gas studies (2024), reported by TechXplore: "Meta-analysis paves the way for safer batteries".
4. QBE European Operations (11 May 2026). UK fire brigades tackling lithium-ion fire every five hours. Based on Freedom of Information responses from 42 of 49 UK fire services. qbeeurope.com
5. Trew, P. (Institution of Fire Engineers), "Understanding EV fire risks", Transport Engineer.
6. Scientific American, "Thermal Runaway Explains Why Waymo Cars Burned So Completely in the Recent Los Angeles Protests", citing a 2023 Finnish study on fire rates.

Editors Note: Items 3 and 6 are secondary reports, and I haven't read the full papers. Please check the volume and DOI for Larsson et al. (2017) before printing or quoting.