Tesla Battery Fire in California Leaves Four Firefighters Disabled
A NIOSH report reveals that four firefighters remain out of work nearly a year after inhaling toxic smoke during a Tesla Model 3 thermal runaway incident in California.
A routine response to a Tesla vehicle accident in California escalated into a hazardous materials incident with long-term health consequences for first responders, according to a newly released report. The U.S. National Institute for Occupational Safety and Health (NIOSH) revealed that five firefighters were injured after being exposed to toxic smoke emitted from a damaged lithium-ion battery of a Tesla Model 3. Nearly a year after the incident, four of the firefighters have still been unable to return to work.
The incident took place in April 2025 after the electric vehicle collided with a tree in a residential neighborhood. The force of the impact caused significant damage to the battery pack, scattering more than 400 battery cells across the roadway. Some of the cells emitted popping sounds and released smoke, leading authorities to initially classify the event as a Level 2 hazardous materials incident.
Thermal Runaway During Vehicle Recovery
The most perilous phase occurred after the situation appeared to be under control. Firefighters had gathered the scattered cells and were clearing the scene when a tow truck arrived to remove the wreckage. As the damaged Tesla was being loaded onto the flatbed, the remaining portion of the battery pack entered a state of thermal runaway—an uncontrollable exothermic process where the battery rapidly heats up and continuously generates intense thermal energy.
The vehicle began emitting a thick, white cloud that, unlike ordinary smoke, did not rise and disperse but instead hovered closely along the ground. The low-lying toxic cloud reached several firefighters who had already removed their self-contained breathing apparatus. Exposure times ranged from mere seconds to approximately five minutes.
Severe Health Impacts on Responders
All five exposed firefighters immediately reported a metallic taste in their mouths, accompanied by throat and eye irritation, coughing, dizziness, nausea, and vomiting. Three sought emergency room treatment that same night, while two others were hospitalized the following day.
While one firefighter recovered within days, the condition of the other four deteriorated significantly over the following weeks. They developed exertional dyspnea, persistent cough, profound fatigue, elevated heart rate, and hypertension requiring medical intervention. Months later, they also reported cognitive fog, irritability, and mood disturbances.
"Four of the firefighters remain unable to return to work nearly a year after the exposure, suffering from reactive airway disease and significantly diminished pulmonary capacity."
NIOSH Recommendations for Emergency Services
Medical evaluations diagnosed the four firefighters with reactive airway disease resulting from inhalation injury. One responder experienced a dangerous drop in blood oxygen saturation down to 86% during a 100-meter walk test, requiring supplemental oxygen during exertion.
Although NIOSH emphasized that the small cohort prevents broad generalizations regarding all electric vehicle battery exposures, the report warns that thermal runaway releases a complex mixture of toxic gases, heavy metals, particulate matter, and acidic compounds. Consequently, NIOSH has urged fire departments worldwide to treat even non-burning electric vehicles as potential biohazards, mandating continuous respiratory protection throughout overhaul and towing operations until all risks of thermal runaway have completely subsided.
