NFPA Journal

WHERE SHOULD YOU STORE your e-bike battery if you’re concerned it might catch fire? That was a question posed several months ago on Reddit, a popular social media site where users discuss topics ranging from sports to news to emerging technology, including e-bikes.

Dozens of Redditors weighed in. Old grills, ammo cans, toolboxes, and ovens were a few of the top answers. For others, the question—and similar queries posed in other electric bike and electric scooter forums on Reddit—seemed to incite anger. “They don’t catch fire,” one user wrote in June. “Stop fear-mongering.”

Watch a related video about e-bike and e-scooter fire safety.

The truth is battery-powered electric micromobility devices, including the e-bikes and e-scooters that have become immensely popular in recent years, do catch fire. Specifically, it’s their batteries, which are often lithium-ion, that pose a risk. In New York City alone, fire department officials say these devices sparked more than 130 fires so far in 2022, putting the city on pace for more than 160 e-bike or e-scooter fires this year. That would be a roughly 50 percent increase over the 104 blazes the New York City Fire Department (FDNY) reported in 2021, which killed four people. Five people have died in such fires in 2022, including a 5-year-old girl who died in an August 3 blaze sparked by a charging e-scooter.

RELATED CONTENT 
• Faced with the risks, New York City is weighing banning e-bikes and e-scooters from public housing
• Listen to FDNY Chief of Fire Prevention Joe Jardin discuss the e-bike fire problem on The NFPA Podcast  

Despite what you may read online, the key to solving the problem doesn’t lie in storing e-bike batteries in your oven. Instead, experts say a multifaceted approach targeting e-bike and e-scooter manufacturers, building owners, and the public is needed to create a safer future for electric micromobility devices. And the sooner that can happen, they say, the better.

“The majority of lithium-ion battery fires that fire departments across the country are dealing with involve these micromobility devices,” said Matthew Paiss, a technical advisor in the Battery Materials & Systems group of the Pacific Northwest National Laboratory (PNNL). “With something like an electric vehicle fire, you may be able to let it burn on the side of the road. With these, though, they may be in homes and high-rises, so fire departments have to engage. It’s a problem we need to address.”

But the popularity of the devices means that recent efforts to increase regulation of e-bikes and e-scooters in some jurisdictions have been met with resistance and enforcement challenges. Those experiences could set the stage for similar struggles in cities around the world as safety authorities attempt to manage this emerging hazard, and as the electric micromobility market gears up for a period of dramatic growth.

Why do e-bikes burn?

The first electric bicycles emerged in the late 1800s, although production was scant and many designs never made it off the paper. E-bikes enjoyed small bursts of niche-market success through the mid- to late-20th century, but it wasn’t until the past several years that the design and sale of the devices became a viable business model, spurred primarily by a global push to reduce reliance on gas-powered combustion engines. The invention, production, and market viability of electric scooters has followed a similar path to e-bikes.

According to the market research firm Allied Market Research, the global micromobility market is expected to grow from about $40 billion today to $215 billion by 2030, with much of that growth attributed to the boom in battery-powered electric devices. By next year, roughly 40 million e-bikes are expected to be zipping down city streets worldwide. “An incredible transformation of personal electrified transportation technology has taken place around the globe and shows no sign of slowing,” reads a pamphlet titled “Guide to micromobility,” published by Underwriters Laboratories (UL) in March. “More and more, light electric vehicles and personal transportation devices are populating worldwide markets.”

While there’s no comprehensive data on how often e-bikes or e-scooters catch fire, it does happen with some regularity. New York City, for example, has seen a substantial number of e-bike and e-scooter fires in the past two years, according to Joe Jardin, chief of fire prevention at FDNY, and incidents are on the rise. “The numbers increase weekly,” he added. “That’s how active this issue is.”


Photographs taken by FDNY of fire scenes involving e-bikes and e-scooters detail many of the hazards involved with charging and storing the devices. Charging multiple devices can overload electrical circuits or power strips, while poorly manufactured batteries and charging equipment can result in fires that can become severe in a matter of seconds.  Photos courtesy of FDNY  

In India, where a government initiative is calling for 80 percent of two-wheeled micromobility devices to be electric by 2030, a series of e-bike and e-scooter fires made headlines in May and June, with some leading to fatalities. An investigation by the Indian government attributed the blazes to poorly manufactured battery cells, and experts agree that e-bike and e-scooter fires are often caused by battery or other equipment defects. “A lot of these products, including the chargers that come with them, may be constructed with low-quality components,” said Paiss.

But the cause of the fires isn’t always manufacturer error. Companies like Lime and Bird, which provide e-scooter rentals in cities worldwide, have long used a model that employs people to charge their devices overnight—the more scooters you charge, the more you get paid. Not surprisingly, this has led to people overloading electrical circuits. Images posted in online forums for “juicers,” the term used to describe people who get paid to charge e-scooters, show dozens of cords snaking in between scooters plugged into power strips, which are plugged into more power strips before being plugged into outlets.


Paiss said he also has concerns over e-bike and e-scooter batteries being damaged through physical force—like a juicer throwing them into the back of a van or users treating them harshly—or by after-market modifications or repairs. According to an article published last year by New York magazine and the tech news website The Verge, many e-bike-riding food delivery workers in New York City maintain their devices not by seeking repairs at bike shops or another authorized dealer, but instead “with the help of a traveling mechanic known only as Su.”

Regardless of why an e-bike or e-scooter fire starts, when it does, like any other lithium-ion battery fire, it can be exceptionally difficult to control. Fed by a chemical reaction known as thermal runaway, the blazes can spew toxic fumes and generally require copious amounts of water to extinguish. Even when lithium-ion battery fires appear to be out, the batteries can reignite days or even weeks later due to energy that remains trapped inside the damaged battery cells. “It’s scary, frankly, how fast the environment in the fire area diminishes, how severe the fire becomes in a matter of a second or two,” Jardin said.

Cities weigh the risk

After a fatal fire involving an e-bike in New York City in December, Jardin said the city’s fire commissioner banned e-bikes and e-scooters from FDNY headquarters, with the exception of devices used by disabled people. As of April, the New York City Fire Code has also included limitations on storing or charging more than five electric micromobility devices in one area.

The fire code change was made to target the kinds of situations that led to the garage fire in Minnesota. “This provision was intended to effectively prevent use of dwelling units to warehouse and charge fleet e-bikes and other activities involving the bulk storage and charging of powered mobility devices,” Julian Bazel, director of the FDNY Bureau of Fire Prevention’s Code Development Unit, said in a statement sent to NFPA Journal. If a building owner wants to provide a space for residents or workers to store and charge their personal e-bikes or e-scooters, they can, Bazel added, as long as they provide increased protection measures like sprinklers and fire-rated doors and walls.

"
'It’s scary how fast the environment in the fire area diminishes, how severe the fire becomes in a matter of a second or two.'

   
The city could take things a step further with a proposed rule that would ban e-bikes and e-scooters from all public housing, a move that has generated widespread and vocal opposition (see “Big Apple E-ban?”). That resistance could soon be felt elsewhere, too, as e-bikes and e-scooters continue to grow in popularity.

In some places, that back-and-forth has already occurred. After officials in London announced an e-bike and e-scooter ban for the Palace of Westminster, they received backlash from bicycle advocacy groups, members of the public, and members of Parliament. In a February hearing, Anthony Fitzhardinge Gueterbock, a member of the House of Lords who had previously commuted to work on an e-bike, called the move an example of “creeping managerial control” and accused those who made the decision of “misinterpreting” the fire risk e-bikes pose.

Other communities feel no need to crack down on the devices—at least, not yet. In Durham, North Carolina, where electric micromobility devices have been on the scene for several years as both rentals and for personal use, there have been no known fires, according to the fire chief there. “As far as I'm aware, there have been no incidents in our jurisdiction concerning e-scooters or e-bikes,” said Chief Robert Zoldos, who owns his own e-scooter. In one instance, Zoldos was out walking in downtown Durham when a call came in for a large gas leak; he jumped on a rental e-scooter to get back to his vehicle faster so he could respond to the call. “I find the scooters very helpful and efficient,” he said.

Fires involving the devices also don’t seem to be a major problem in nearby Raleigh, where the city employs a micromobility coordinator to oversee e-bike and e-scooter use. Emails between the micromobility coordinator and the city’s deputy fire marshal reveal that concerns over where the devices are ridden, following traffic signals, and wearing helmets are more prominent than concerns over fire safety. 

Uncovering the challenges cities around the country face when it comes to e-bikes or e-scooters is one goal of an upcoming symposium jointly hosted by FDNY, NFPA, and UL’s Fire Safety Research Institute. The “Lithium Ion Batteries: Challenges for the Fire Service” symposium is being planned for September 6 and 7, Jardin said, with an anticipated attendance of about 200 fire service leaders who will come together to review the hazards, share their experiences, and review FDNY’s fire and post-fire mitigation experiences with electric micromobility devices—lessons that could come in handy as other jurisdictions experience more e-bike or e-scooter fires. “Right now, at least, we seem to be seeing this problem at a higher rate than others,” Jardin said. “But I would guess what we’re seeing here will eventually be recognized as a challenge in other places.” (Register to attend the symposium.)

Better devices, fewer fires 

Fires involving e-bikes and e-scooters are often attributed to poorly made batteries and related equipment, including chargers. That trend has angered industry leaders, who believe the cheaper products give all e-bike and e-scooter manufacturers a bad name.

“We are working hard to be responsible, with third-party testing and working with UL standards, and then we have rogue companies that bring in electric scooters from China without any kind of regulations and it creates a bad image,” Larry Pizzi, an executive at a company that owns several e-bike brands, told industry news website bicycleretailer.com in April.

But even when consumers seek out the more expensive, well-known brands of e-bikes and e-scooters, quality—and safety—are no guarantee. Paiss, the PNNL technical adviser, said he bought his own e-bike from a reputable brand, but the charger that came with it was still low quality. “I had to purchase a higher quality one on my own,” he said. “The charger that came from the manufacturer was of such poor quality it could lead to battery damage.”

Beginning in 2016, UL has published UL 2272, a standard for the certification of electrical systems found in personal electric micromobility devices. It came after a spate of fires involving so-called hoverboards, one- or two-wheeled electric devices that riders use like a skateboard. In 2020, UL published a standard specific to e-bikes, UL 2849. The standards ensure, among other things, that a device’s battery management system, or BMS, is able to monitor and prevent problems like overheating.


GETTY IMAGES

It’s unclear what percentage of e-bikes or e-scooters on the market are UL-listed to either of those standards, and it can be tricky for consumers to ensure what they’re getting is as safe as possible. In 2019, UL issued a warning to consumers that there were devices being sold bearing fake UL certification stickers. There are also some manufacturers that appear to sell both listed and unlisted devices, with the listed items priced higher.

“This certification adds cost to an e-bike company (and the consumer), so the e-bike industry has yet to widely adopt UL 2849,” Jim McIlvain, a former editor of several motocross and mountain biking magazines, wrote in a blog post published in the fall of 2021. Still, McIlvain said he remained optimistic that things would change. “Why so optimistic?” he wrote. “The e-bike industry is overheated (no pun intended) by competition. A company may feel that adding any expense puts them at a competitive disadvantage (especially since the industry has been so successful keeping e-bike fires under the radar). Still, the brands who see UL 2849 as value added, not a cost, will immediately stand out from the competition, appealing to riders who want the assurance that the e-bikes in their home do not pose an extreme fire threat.”

It’s also unclear what impact, if any, the emergence of UL-listed devices has had on fire incidents. “One of the questions I have with these incidents increasing is whether they’re occurring in UL-listed devices,” said Paiss.

There’s at least some anecdotal evidence to suggest that since companies like Lime and Bird have started using UL-listed devices, they’ve seen a drop in fires. “The very first generation of scooters used by Lime, Bird, and others did have a problem with overcharging, which causes batteries to overheat,” a Lime juicer wrote on Reddit in June. “This was back in 2018. What they’ve got now … I can [charge] all night and it won’t even heat up. I’ve seen them run over [by vehicles], with bullet dents in them, thrown in the river, dropped off overpasses—they’re tough as hell and just come back for more.” In the news, reports of fires involving devices from these companies appear to have declined in the past few years, leaving mostly incidents that involve personal devices.

Given the benefits a UL listing can bring to e-bikes and e-scooters, many safety officials and bicycle enthusiasts like McIlvain have made it a point to recommend that consumers only shop for UL-listed products. It’s one area in the world of e-bikes and e-scooters where it seems regulation is more universally accepted, compared to the outcry that actions taken recently in New York and London can provoke. “While some of these bikes and scooters themselves can be fairly robust, when you’re getting damage, you have no idea what’s happening to that BMS or those circuits,” said Paiss. “Having that listing is incredibly important.”

Experts hope changes that have been proposed for NFPA 1, Fire Code, will move the needle further on getting more e-bikes and e-scooters UL-listed. Similar to the New York City fire code change that took effect in April, the changes proposed for the 2024 edition of NFPA 1 would include enhanced safety requirements wherever more than five electric micromobility devices are being charged. Part of those requirements would be ensuring the devices and their charging equipment are UL-listed.

Kelly Nicolello, a senior regulatory engineer at UL and member of the Fundamentals of the Fire Code committee, submitted the proposal to add the new language last year. “This proposal sets reasonable safety requirements to mitigate the hazards associated with the charging of these devices,” Nicolello wrote, defending his proposal in a public input. “The proper use of listed powered micromobility devices, portable power packs, and compatible chargers will reduce the fire incidents that have occurred with nonlisted or incompatible charging arrangements.”