Electric Vehicle Fire Reignites Days After Crash: Why Thermal Runaway Is a Growing Safety Concern
A recent incident in New Hampshire highlights the unique dangers of lithium-ion battery fires — and why preparedness matters.
When actor and comedian Eugene Mirman's Lucid Gravity struck the Bedford Toll Plaza on March 31 and burst into flames, first responders handled the immediate emergency. But the story didn't end there.
Days later, while sitting in a tow yard in Merrimack, the badly damaged electric vehicle reignited — smoke rising from the batteries before turning into open flames. Merrimack Fire Chief Joseph Guarnera said crews extinguished the fire in about 30 minutes but remained on scene for over two hours, knowing full well that electric vehicle fire events like these have a tendency to flare up again.
The culprit? A phenomenon known as thermal runaway.
What Is Thermal Runaway?
Thermal runaway occurs when lithium-ion battery cells begin heating up uncontrollably, triggering a chain reaction that spreads from cell to cell. As Chief Guarnera explained, "These fires can happen up to 30 days after the original incident, contingent upon the batteries. And if one starts to heat up, they're all likely to."
According to the National Fire Protection Association (NFPA), damaged batteries contain what's called "stranded energy" — residual energy trapped inside even after a fire has been extinguished. There's currently no reliable way to measure how much energy remains, which means a vehicle involved in a fire can reignite days or even weeks later.
Making matters worse, lithium-ion batteries can release toxic chemicals and, under certain conditions, even cause explosions.
A Growing Transportation Safety Challenge
This incident underscores a critical safety challenge facing the transportation industry as electric vehicle adoption continues to accelerate. While the NFPA does not say EVs are more dangerous or more likely to catch fire than traditional internal combustion engine vehicles, they do acknowledge that EV fires behave differently — and those differences demand new approaches from first responders, tow operators, and storage facilities alike.
Traditional firefighting methods aren't always sufficient. EV fires burn hotter, last longer, and — as this case demonstrates — can reignite long after everyone assumes the danger has passed.
How Do You Protect Against Reignition?
This is exactly the kind of scenario that keeps us up at night here at FireFibers — and exactly why we developed our lithium-ion fire blankets.
Our fire blankets are specifically engineered to contain and suppress lithium-ion battery fires, including the unpredictable reignition events caused by thermal runaway. Whether deployed by first responders at the scene of a crash, used in tow yards storing damaged EVs, or kept on hand at fleet maintenance facilities, FireFibers blankets provide an essential layer of protection during the critical window when reignition is most likely.
Key benefits include:
- Immediate containment of flames and toxic fumes
- Extended suppression during the stranded energy window
- Portable and easy to deploy — no specialized training required
- Designed specifically for lithium-ion battery fires, not just adapted from traditional fire suppression tools
The Bottom Line
The Merrimack reignition is a reminder that an electric vehicle fire doesn't end when the flames go out. For tow companies, fire departments, fleet managers, and anyone in the EV ecosystem, being prepared for what happens after the initial incident is just as important as responding to the fire itself.
Don't wait for a reignition event to catch you off guard. Contact FireFibers today to learn how our lithium-ion fire blankets can protect your team, your facility, and your community.
