According to the Edison Electric Institute, there were more than 1.18 million electric vehicles in the U.S. on the road as of 2019. And the market is only growing. Industry experts predict 2020 to be the “year of the electric car” as sales are expected to soar, and more car manufacturers enter the EV arena. Major players in the car industry like Chevrolet, Honda, BMW, and Hyundai are among just a few releasing new EV models in 2020.
The increase in EVs and hybrids on the road is impacting the U.S. infrastructure of vehicles. For example, the demand for more charging stations and the learning curve for mechanics working on these innovative vehicles. It’s a new frontier. One of the lesser known yet immensely impactful changes to American roadways is the fire hazard these vehicles present. Electric vehicle fires are dangerous and quite complicated.
Fire hazards of electric vehicles
The unique fire hazards that EVs and hybrid vehicles present pose challenges particularly for first responders.
Electric vehicle fires can exceed 5,000 degrees Fahrenheit. Applying water or foam may cause a violent flare-up as the water molecules separate into explosive hydrogen and oxygen gases.
There are several common risks for first responders associated with electric vehicle fires:
- Electrical shock (up to 400 volts)
- Extremely high temperatures and thermal runaway
- Toxic fumes
- Lithium burns (respiratory and skin reactions)
- Toxic runoff
- Reignition up to 24 hours after initial extinguishment
Other dangers of EVs are thermal runaway and stranded energy, should a crash occur. A recent article in NFPA Journal details the narrative of a Tesla crash on a California highway and the immense challenges posed to first responders. In the article, the author describes the Tesla battery in particular:
“As in all Tesla models, the battery in the Model X is comprised of more than a dozen separate modules, each made up of hundreds of individual cells. All of these components are neatly packaged in a rectangular metallic case that runs the length of the chassis beneath the passenger cabin. Fully charged, the battery has a capacity of 75 kWh—roughly enough energy to power the average US home for more than two-and-a-half days, and more than enough to instantly kill anyone exposed to it. If punctured, breached, or otherwise damaged, heat can build rapidly inside the compromised battery cells and spread to surrounding cells in a cascade-like process called thermal runaway, which can lead to fire, arc flashing, off gassing, and sometimes explosions.”
This crash is an example of the unique challenges facing the vehicle industry and first responders. And a call for more research and training in handling EV incidents.
NFPA’s Alternative Fuel Vehicles Safety Training Program works with major auto manufacturers, subject matter experts, fire, law enforcement, and safety organizations to address the safety needs of EVs and hybrid vehicles. The goal of the program is education and awareness to mitigate the dangers of these vehicles.
A few important tips for first responders per this NFPA program include:
- When suppressing a vehicle fire involving an EV or hybrid, water is the recommended extinguishment agent. Large amounts of water may be required, so be sure to establish a sufficient water supply before operations commence.
- As with all vehicle fires, toxic byproducts will be given off, so NFPA compliant firefighting PPE and SCBA should be utilized at all times.
- DO NOT attempt to pierce the engine or battery compartment of the vehicle to allow water permeation, as you could accidentally penetrate high voltage components.
- Following extinguishment, use a thermal imaging camera to determine the temperature fluctuation of the high voltage battery before terminating the incident, to reduce re-ignition potential.
These tips and trainings are critical moving forward into this new frontier of managing electric vehicle fires. But is this enough?
Current solutions & future plans
EVs and hybrids have been on the road for several years. But we’re just now on the forefront of navigating issues involving alternative fuel vehicles. Programs like NFPA’s Alternative Fuel Vehicles Safety Training are critical in proving training, tools, and information for emergency responders to safely handle emergencies involving alternative fuel vehicles. There are also other programs and solutions in the works.
A major challenge for first responders is getting to the battery of EVs. Some vehicle manufacturers are addressing this issue by manufacturing electric vehicles so that emergency response personnel can access the battery to extinguish fire or remove. The hope is that this will be the norm going forward.
Another tool in the works for first responders is better DC hot stick technology. A hot stick is a tool used for detecting the presence of AC voltage in a wire. The problem is that it does not test for DC voltage, found in EVs among other things. This new tool would help prevent first responder electrical injury by allowing for safe detection of DC voltage using existing AC probes.
Extinguishing lithium batteries like those used in Teslas requires massive amounts of water. They also require “quarantine” for up to 48 hours after catching fire, per Tesla’s own emergency response guide. A vehicle suppression system like those found on heavy machinery would be overall ineffective in the full extinguishment of a battery fire. Since these high-powered batteries require supervision for days, and removal from the vehicle any way, it seems the best way to battle these blazes is through education, training, and new tools to help firefighters and first responders.