This informal CPD article’ Electric Vehicle & Lithium‑Ion Battery Fires: Understanding the Hazardous Material Risks’ was provided by Golden Fleece Fire Safety, a UK based organisation dedicated to delivering innovative, experience-driven fire safety solutions that reflect the real-world needs of modern emergency response teams.
Introduction
As electric vehicles, e‑scooters and battery‑powered machinery become more common across the UK, fire crews, safety managers and site operators are dealing with a new and very different type of risk. While lithium‑ion technology brings clear environmental and operational benefits, incidents involving thermal runaway create chemical hazards that are nothing like those from traditional petrol or diesel vehicles.
What many people do not yet fully understand is that these are not just fires — they are hazardous material events. The by‑products released are toxic, corrosive and invisible, and they leave behind contamination that standard cleaning simply cannot remove. This article sets out clearly what those risks are, why they matter, and what is required to properly manage them.
What is released during a lithium‑ion or EV fire?
When a battery overheats and enters thermal runaway, the chemical structure inside the cells breaks down rapidly. It does not just burn away; it releases a complex mix of gases, liquids and fine solid particles. Independent testing and incident analysis have identified over 150 different compounds in these emissions, many of which are harmful to health or damaging to equipment¹.
The four most dangerous and persistent hazards are:
1. Hydrofluoric Acid (HF)
This is the single biggest hidden danger. It forms when fluorinated electrolytes inside the battery break down. Even in low concentrations, hydrofluoric acid is extremely aggressive. Unlike other acids which cause immediate burning, HF can be absorbed through the skin without pain, working its way into deep tissue and bone, and interfering with the body’s natural calcium levels. It can exist as a gas, a liquid residue or a fine dust, meaning it can be breathed in, ingested or picked up by touching surfaces, clothing or equipment².
2. Fluoride Compounds & Corrosive Salts
Lithium‑ion cells contain metal salts and fluorine‑based chemicals. When released, these settle as a sticky or powdery residue. These compounds are chemically active — they attract moisture from the air and remain corrosive long after the fire is out. Crucially, they are highly soluble in water, which means that if you try to wash them away with standard methods, you often just spread the contamination over a wider area.
3. Heavy Metals & Respirable Dust
Cobalt, nickel, manganese and copper are all key components of battery cells. When burned, these turn into microscopic dust particles small enough to be breathed deep into the lungs. Long‑term exposure is linked to serious respiratory conditions and organ damage. Because these particles are so small, they get trapped inside fabric fibres, seams, coatings and insulation — and they do not come out with normal washing.
4. Solvents & Organic Vapours
The liquid electrolyte inside batteries is made up of volatile solvents. When heated, these turn into vapours or oily residues that repel water and standard detergents. They contribute to the thick, toxic smoke plume and leave behind a film that is hard to detect but remains hazardous.
Hydrofluoric acid is extremely aggressive
The invisible problem: why standard cleaning fails
One of the most dangerous misconceptions is that if something looks clean, it is clean. After an EV fire, a containment blanket, a set of fire kit or a road surface might appear perfectly normal once the soot is gone — yet still carry dangerous levels of fluoride or heavy metals.
Standard industrial cleaning, laundering or pressure washing is designed to remove carbon, smoke and general dirt. It works well for fires involving wood, paper or fossil fuels — but it is chemically useless against lithium‑ion residues. These compounds are chemically bonded or physically trapped within materials. Water and soap cannot neutralise them, and they cannot be simply “washed out”.
Research from the Fire Protection Research Foundation confirms this:
“Residues from lithium‑ion thermal runaway remain hazardous until specifically treated. Traditional cleaning methods do not reduce contamination to safe limits.”³
This creates a serious risk: equipment returned to service after basic cleaning is still contaminated. Every time it is handled or worn, it exposes crews and staff to toxic materials.
Safe decontamination must be based on science
To make equipment safe again, you have to address the chemistry of the hazard. This is not just cleaning — it is a chemical process. There are three essential stages that must be followed:
1. Chemical Neutralisation
You cannot just wash the residue away. You have to apply specialist agents that react with hydrofluoric acid and fluoride salts, converting them into stable, non‑toxic compounds. Only once that reaction has happened is the hazard truly gone.
2. Deep Extraction
Because residues penetrate deep into fabrics and materials, the process must be designed to lift and remove particles from within the structure, not just from the surface.
3. Verification & Certification
You cannot tell if it is safe just by looking. Every item should be tested to prove that contamination levels are below recognised safe exposure thresholds. A formal certificate of decontamination is not just a piece of paper — it is the legal proof that the job has been done properly and that the item is safe to use again.
Legal & regulatory duties
Under the Control of Substances Hazardous to Health Regulations 2002 (COSHH), employers and operators have a clear legal duty to control exposure to dangerous substances. This includes making sure that any equipment exposed to hazardous materials is properly cleaned and certified safe before being returned to use⁴.
In the case of lithium‑ion or EV fires, failing to use a properly validated decontamination process is a breach of that duty. There are also strict rules under the Environmental Protection Act 1990 covering how contaminated waste, water and residues are handled and disposed of — these are classified as hazardous waste and must be managed by authorised contractors⁵.
Conclusion
The move towards electric transport and battery technology is necessary and positive — but it brings risks that we are still learning to manage. The by‑products of a lithium‑ion fire are chemically unique, highly dangerous and invisible to the naked eye.
Standard cleaning is not enough. It leaves contamination behind, and it leaves people exposed.
Understanding the difference between washing and decontamination is vital. Only a process built on proper chemical science, independent testing and formal certification can truly eliminate the risk. Safety means knowing that what you cannot see cannot hurt you — and that requires proof.
We hope this article was helpful. For more information from Golden Fleece Fire Safety, please visit their CPD Member Directory page. Alternatively, you can go to the CPD Industry Hubs for more articles, courses and events relevant to your Continuing Professional Development requirements.
References
- Fire Protection Research Foundation (2024). Chemical Emissions from Lithium‑Ion Battery Fires. National Fire Protection Association (NFPA), USA.
- Health & Safety Executive (HSE) (2023). Hydrofluoric Acid: Health Hazards and Control Measures. Guidance Note INDG243.
- International Association of Fire Chiefs (IAFC) (2025). EV Fire Residue Management & Decontamination Best Practice.
- The Control of Substances Hazardous to Health Regulations 2002 (SI 2002/2677). UK Legislation.
- Environment Agency (2024). Hazardous Waste: Classification and Management of Lithium‑Ion Battery Fire Residues.
