Video Summary
Battery gas can ignite extremely fast—e-bike ignition occurred in as little as 1 second after visible gas, e-scooter in 7 seconds.
Smoke spreads through a full-length commuter car in seconds; midpoint was reached within ~10–12 seconds in tests.
Visibility can be fully lost across a car in a few minutes; some tests showed no visibility within ~3–4 minutes.
People within about 10 ft of a failing device risk incapacitation from heat or flames within 20–60 seconds.
Ideal evacuation of a stopped train takes ~1 minute 45 seconds; in worse scenarios it can exceed 4 minutes—often longer than safe conditions allow once smoke spreads.
Tests showed ignition can occur extremely quickly—an e-bike ignited within 1 second of first visible battery gas, an overhead e-scooter in 7 seconds, though some configurations delayed ignition up to ~90 seconds.
Smoke reached the midpoint of the car within about 10–12 seconds and the far end within ~26–28 seconds in several tests, demonstrating very rapid spread.
Under ideal, already-stopped conditions evacuation took about 1 minute 45 seconds in prior research, but in less favorable scenarios it can exceed 4 minutes—often longer than the safe window once smoke and reduced visibility develop.
Recommendations include physically isolating device storage from seating, ventilating storage spaces, limiting allowed battery capacity (around 100 Wh), and public education on lithium-ion hazards.
"On New Year's Eve, 2023, a subway car in Toronto experienced a thermal runaway from an e-bike while people were still inside."
On December 31, 2023, a significant incident occurred involving an e-bike in a subway car in Toronto.
Fortunately, the e-bike caught fire just as the train reached the station and opened its doors, potentially preventing greater harm.
Last year, the speaker, along with John Orlando, a retired FDNY fire marshal, discussed the risks surrounding lithium-ion batteries in public transport.
"The Fire Safety Research Institute conducted full-scale fire tests inside an inner-city commuter rail car in October of 2024."
In October 2024, the Fire Safety Research Institute performed extensive fire simulations within a full-scale commuter rail car.
This rail car measured 85 feet long, 10.5 feet wide, and 12.5 feet tall, with 72 seats and multiple doors for passenger access.
The researchers equipped the rail car with various measurement devices to monitor thermal responses and gas emissions during the tests.
"From the moment the battery gas was first visible, the time to ignition was only 7 seconds."
The first experiment involved an e-scooter placed in an overhead rack, which ignited in just 7 seconds after visible battery gas appeared.
The fire resulted in a fireball that traveled across the ceiling, creating a dangerous environment.
Anyone within a 5-foot radius could be incapacitated by the fire in approximately 17 seconds, highlighting the urgency of evacuation.
"The e-bike ignited faster, taking only 1 second from first visible battery gas to ignition."
In a separate test, an e-bike hung by its rear wheel ignited much faster than the e-scooter, with ignition occurring within 1 second of gas visibility.
Although the fire did not generate enough heat to incapacitate individuals in the measured distances, it remains a significant hazard.
Smoke from this e-bike fire reached the midpoint of the car in just 10 seconds, emphasizing the rapid danger posed by smoke-filled environments.
"If you're within 10 feet of a device, you could be incapacitated by fire within 20 to 60 seconds."
Data from all experiments confirmed that smoke travels quickly through rail cars, and full visibility can be lost in a short timeframe.
Standing inside a car, a person could face untenable conditions roughly 5 minutes post-ignition due to smoke accumulation.
Notably, in typical fire scenarios, victims are often overcome by smoke rather than the direct heat.
"Research indicated that it would take around 1 minute and 45 seconds to evacuate a train under ideal conditions."
Existing studies suggest it requires about 1 minute and 45 seconds to evacuate a train when it is stationary and accessible.
Under less favorable circumstances, such as delays in recognizing a fire, evacuation can extend to over 4 minutes.
The inherent challenges of the subway system, including locked doors and delays in communication, could severely compromise safety during a fire incident.
"The FSRI recommends physically isolating storage areas from seating and educating the public on lithium-ion battery hazards."
To enhance safety, it's advised to separate e-scooters and e-bikes from passenger seating areas and ensure proper ventilation of storage compartments.
Furthermore, limiting the size of lithium-ion batteries allowed on public transportation is crucial, with 100 watt-hours identified as an ideal maximum.
Public education on the dangers associated with these devices is essential to prevent future incidents and safeguard lives.
