What the recycling industry can learn from residential lithium-ion battery fires

In November 2024, a 20V DeWalt lithium-ion battery fire in a Newfoundland home led to an unexpected discovery.

A week after the fire, Clean Core Research conducted an in-depth investigation, focusing on the long-term effects of lithium-ion battery soot. The key finding? Soot from the fire was actively corroding metal surfaces, including electrical infrastructure that was never directly exposed to flames. 

Soot from lithium battery fires corrodes metal even without direct flame contact

When we examined the home's electrical panel, we found that busbars exposed to soot showed significant pitting corrosion, while areas protected by breakers remained intact. This strongly suggested that the soot itself was chemically attacking the metal. Tools in the home also rusted rapidly, and electrical components, such as outlets, light fixtures, and connectors, showed early signs of chemical degradation. 

Fire damage spreads far beyond the burn site

What stood out was that these effects weren’t limited to the immediate area of the fire. Corrosion was occurring in parts of the home located far from the burn site. The presence of fine soot in the HVAC system indicated that combustion by-products had dispersed throughout the home, affecting wiring, electronics, and household surfaces over time. 

Moisture accelerates lithium battery fire damage

Further testing showed that moisture in the air was accelerating corrosion. When lithium-ion batteries combust, they release not just heat but also highly reactive gases that mix with airborne soot and settle onto surrounding materials.

Once deposited, these chemicals don't just sit there; they continue reacting, breaking down metals and materials in a slow, corrosive process that traditional fire restoration techniques don't fully address. 

The science behind lithium-ion battery fire residue 

Unlike typical fire residue, lithium-ion battery fires produce an array of toxic and corrosive by-products, including: 

• Hydrofluoric acid (HF): Capable of etching glass and aggressively corroding metals. 
• Hydrogen chloride (HCl): Reacts with humidity to form hydrochloric acid, which accelerates rust and pitting.
• Sulphur dioxide (SO₂) and phosphoric acid: Known for breaking down protective coatings on metal surfaces, making them more susceptible to oxidation. 

Basic cleaning methods do not neutralize these chemicals. Even if soot is physically removed, residual acids can continue damaging materials. 

How corrosion happens 

1. Acidic fire by-products: Gases like HF and HCl combine with moisture to form highly reactive acids. 
2. Soot deposition: Carbonized particles from the fire trap these acids against metal surfaces. 
3. Slow degradation: As moisture levels fluctuate, the trapped chemicals continue to react, worsening the damage over time. 

Insurance companies are not prepared for lithium battery fires

Despite clear evidence of ongoing corrosion, the homeowners’ insurance provider maintained that the fire had only caused direct damage, overlooking concerns about potential hidden impacts. Requests for further investigation, including attic and HVAC contamination testing, were not approved. 

The insurance adjusters suggested that the electrical panel could simply be wiped down, a perspective that highlights the need for greater awareness around these events. Newfoundland’s chief electrical inspector found the suggestion surprising, noting that while wiping may remove visible soot, it does nothing to address the embedded chemical degradation that can compromise safety and functionality. 

Beyond electrical components, the potential long-term effects of lithium battery fire residue on other household materials were largely overlooked. HF exposure can gradually deteriorate plastics, rubber seals, and insulation materials. Soft goods like clothing and furniture can also become contaminated and may be difficult to fully restore. However, these factors are often underestimated in insurance assessments. 

The bigger issue: Underestimating lithium-ion battery fire risks

• Standard fire restoration methods are not enough; lithium battery soot is chemically active and requires specialized neutralization.
• Structural and electrical damage can occur far from the fire itself, as corrosive soot spreads through HVAC and ventilation systems. 
• Firefighter gear, equipment, and even HVAC systems exposed to battery fire residue may require specialized decontamination. 
• Airborne toxins from lithium battery fires can impact indoor air quality long after the fire is extinguished. 

What needs to change? 

1. Insurance providers must acknowledge the full impact of lithium-ion battery fire contamination. Instead of focusing solely on charred materials, insurers need to consider chemical damage and corrosion. 
2. Fire restoration professionals need specialized training in lithium-ion battery fire cleanup. Traditional fire restoration methods fail to address the lingering hazards of HF, HCl, and other reactive by-products. 
3. Homeowners should demand proper post-fire assessments, including testing for airborne and settled contaminants. HVAC and electrical inspections should be standard protocol in lithium-ion fire recovery efforts. 
4. Firefighters and first responders must recognize contamination risks to their PPE and equipment. Exposure to lithium-ion battery soot can degrade turnout gear, requiring advanced decontamination methods beyond routine cleaning. 

Updating fire restoration standards for battery fires

This investigation in Newfoundland confirms that lithium-ion battery fires cause damage beyond what’s immediately visible. The chemical by-products continue attacking materials long after the flames are gone, and standard cleanup methods fail to address these ongoing hazards. 

At Clean Core Research, we are pushing for updated fire restoration standards that reflect the unique risks posed by lithium battery fires. As these batteries become more common, fire safety, insurance policies, and restoration practices must evolve to meet the challenge.