SF Legislation Aims to Crack Down on Uncertified Batteries as Fires Grow More Common

As fires sparked by lithium-ion batteries become more common, San Francisco Supervisor Bilal Mahmood and the Fire Department are introducing legislation to outlaw uncertified batteries and devices in the city.

Mahmood drafted the legislation in response to a fire started by a lithium-ion battery that ripped through a Tenderloin apartment building in December, displacing dozens of families in Mahmood’s district.

The blaze is part of a growing trend in San Francisco. According to a press release from Mahmood’s office, the city saw 120 lithium-ion battery-related incidents from 2024 to 2025, with dozens concentrated in and around the Tenderloin, and Fire Department data shows related structure fires have been on the rise for several years.

Other cities are also seeing increases in lithium-ion battery fires; in San José, officials raised warnings about buying, storing and charging devices with the batteries after a man died in an apartment fire on Friday linked to an e-bike.

In addition to e-bikes, lithium-ion batteries can be found in common household items such as phones, computers and cordless vacuums. While the batteries are favored for being lightweight and rechargeable, these qualities can also make them a fire hazard — especially when they lack certification or are improperly charged and stored.

“There’s no real warning,” Fire Lt. Mariano Elias said. They start with a bit of smoke before sparks begin to fly and they explode in a big, bright flash. After that, “the fire is off and running very quickly,” releasing clouds of toxic smoke that pose a danger to firefighters and the community.

Not only do they start fast, but they are hard to put out. The fire becomes more difficult to extinguish because “we’re kind of fighting the casing of the battery,” Elias said, referring to a plastic coating designed to keep water out.

Batteries sold commercially in the U.S. are often tested and certified by labs such as UL Solutions to ensure they meet safety standards. But the San Francisco Fire Department found that many of the city’s battery-sparked blazes were caused by non-certified lithium-ion batteries.

Consumer watchdogs and reviewers have noted that while fires caused by devices like e-bikes are still relatively rare, some budget models with less reputable, unbranded parts are more likely to include dangerous non-certified batteries.

“The problem here is not e-bikes and scooters, the problem is when people are using non-UL certified batteries in them,” Mahmood said.

His ordinance, which was set to be introduced at Tuesday afternoon’s Board of Supervisors meeting, aims to solve this problem upstream by prohibiting the sale of uncertified lithium-ion batteries, authorizing enforcement by the San Francisco Fire Department and establishing penalties of up to $1,000 per violation.

Glen Martin, the owner of In and Out E-Bike Repair in the Mission District, believes this legislation will have a positive impact. “I think the highest standards need to be employed behind these batteries,” Martin said.

While there is a state law in California that regulates lithium-ion batteries, Mahmood said his law would go further by regulating the online delivery component and giving the fire chief authority to issue citations.

In addition to the new legislation, the Fire Department is working hard to increase public awareness around lithium-ion battery safety and telling citizens to spot fires early.

The Fire Department recommends taking precautions such as only using the manufacturer’s charger, storing your e-bikes and scooters away from exits, and charging on flat, non-combustible surfaces out of direct sunlight (i.e., don’t leave your phone on the bed while it’s charging). If you hear popping or hissing, see a bulging battery or feel the device temperature rising, you may be in trouble.

KQED’s Ayah Ali-Ahmad contributed to this report.