In May 2025, the National Fire Protection Association (NFPA USA), in collaboration with the Energy Security Agency (ESA), the Fire Risk Alliance (FRA), and other technical partners, conducted a comprehensive series of lithium-ion electric vehicle (EV) battery fire tests at Rockland County Fire Training Ground in New York. These tests form part of a global research effort to better understand the behaviour of battery fires and to develop safe, evidence-based response practices for emergency services and industry.
CESAT is closely aligned with this research. Our purpose is to ensure that emergency responders, environmental service providers, municipalities, and private sector facilities receive accurate, science-driven guidance based on real-world testing — not assumptions or marketing claims.
Research Focus: Stranded Energy and Real-World Firefighting Tactics
A key component of NFPA’s testing program focused on how to manage “stranded energy” — the residual electrical energy that can remain inside a damaged lithium-ion battery pack. Stranded energy can lead to delayed ignition hours, days, or even weeks after the initial event, which is why EV incidents require careful monitoring and methodical response protocols.
To support this objective, several firefighting strategies and suppression tools were tested under controlled conditions, including the use of a commercial EV fire blanket and tilting of a vehicle.
One test that really stood out was the use of the EV Fire Blanket.
What Happened During the EV Fire Blanket Test
The tested EV contained a large 110 kWh battery pack that was deliberately placed into active thermal runaway. After an initial water knock-down of visible flames, a non-porous EV fire blanket was deployed over the vehicle for approximately one hour.
While the blanket reduced visible open flames from interior materials, it did not stop the thermal runaway occurring inside the battery pack. Instead:
- Dangerous off-gases continued to accumulate beneath the blanket.
- Hydrogen and volatile hydrocarbons built up in significant concentration.
- When a corner of the blanket was lifted to remove accumulated water and begin extraction, oxygen re-entered the environment.
This resulted in a violent deflagration event — a rapid ignition of trapped gases — strong enough to physically impact the firefighting team on scene.
This outcome reinforces a critical safety point: EV fire blankets may suppress flames, but they do not suppress lithium-ion battery thermal runaway, and they may unintentionally create an environment where explosive gases can accumulate.
Why This Matters
Lithium-ion battery fires behave differently from conventional vehicle fires. They release:
- Hydrogen
- Carbon monoxide
- Flammable organic vapours
Research led by Emeritus Professor Paul Christensen has shown that hydrogen frequently makes up nearly half of all gases released during thermal runaway. Hydrogen accumulation beneath a sealed barrier creates a known explosion hazard. Reintroducing oxygen — even by lifting a small area of blanket — can trigger sudden, violent ignition.
Implications for Operational Safety
This NFPA research confirms that EV fire blankets should never be used as a standalone “solution” for EV battery fire control. Fire blankets may create more risk than they reduce. Fire services that choose to employ these tools must do so with clear procedures focused on off-gas monitoring, ventilation, and post-suppression hazard awareness.
CESAT Key Takeaways
- EV battery fires require specialized training and disciplined response. There is no one-size-fits all answer. There are no shortcuts. Multiple tools in the firefighters tool kit will be required and they are all dependent on the situation.
- EV fire blankets do not stop thermal runaway. IMPORTANT: Flame suppression does not equal extinguishment.
- Improper blanket use may create explosion hazards by trapping flammable gases.
- Safety decisions must be based on validated research, not product marketing.
- Coordinated monitoring and post-incident protocols are essential due to stranded energy and risk of delayed re-ignition.
CESAT’s Position
CESAT endorses NFPA’s evidence-based approach to EV incident response. We strongly advise organizations, municipalities, and responders to:
- Rely on certified training, not assumptions.
- Use validated containment and transport solutions that meet P911 and relevant test standards.
- Avoid deploying EV fire blankets without trained oversight, clear protocol, and gas hazard awareness.
Our priority is responder safety, public safety, and operational clarity — grounded in real data, not speculation.
View the complete NFPA webinar here: Assessment of EV Firefighting Tactics and Tools