New research from the Fire Safety Research Institute (FSRI) has shown that fire blanket use during electric vehicle (EV) battery fires may pose an explosion risk.
According to FSRI, which is part of UL Research Institutes, the hazard arises when thermal runaway continues under a fire blanket after it has suppressed visible flames.
The Fire Protection Research Foundation (FPRF), the research affiliate of the National Fire Protection Association (NFPA), jointly announced the findings with FSRI on May 30, 2025.
FSRI reported that during recent experiments on battery-involved EV fires, the use of a fire blanket successfully suppressed open flames by limiting oxygen access.
However, thermal runaway continued beneath the blanket, resulting in the release of flammable gases that accumulated under the covering.
In some tests, this build-up presented a risk of explosion, particularly if air was reintroduced into the oxygen-depleted space while the gases remained unburned.
The FPRF stated that these findings form part of its Assessment of EV Firefighting Tactics, Tools and the Impact on Stranded Energy research project.
The foundation is evaluating four suppression methods for EV battery pack fires: water only hose streams, water with injected agents, fire blankets, and firefighting appliances.
Preliminary results will be presented on June 16, 2025, at the NFPA Conference and Expo in Las Vegas.
The full research report will be released in fall 2025 through the FPRF website.
FSRI explained that its work is part of the Fire Safety of Batteries and Electric Vehicles project.
The experiments included use of water application, under-vehicle nozzles, and fire blankets on vehicles with confirmed battery involvement.
FSRI said video and data analysis is underway, and results will be detailed in an upcoming public research report available at fsri.org.
FSRI and FPRF reported a potential explosion hazard when fire blankets are used in EV fires.
The experiments showed that while fire blankets suppress flames, they do not stop thermal runaway in the battery.
This ongoing reaction releases flammable gases under the blanket.
In some experiments, these gases accumulated to explosive levels.
The hazard increases if oxygen is reintroduced while gases remain unignited.
FPRF’s findings are part of a wider study on EV firefighting tactics.
The foundation is testing four methods, including blankets and hose stream types.
Results from this study will be presented at NFPA’s June 2025 conference.
FSRI is conducting its own battery fire suppression experiments.
Their analysis focuses on hose streams, underbody nozzles, and blanket use.
FSRI’s research report will be published later in 2025.
