Consumers should not buy or use individual 18650 lithium-ion battery cells due to possible fire risk, according to a warning just issued by the Consumer Product Safety Commission (CPSC). The commission says it is working with e-commerce sites like eBay to remove listings of loose 18650 cells, which are sometimes used in vapes, e-cigarettes, flashlights, and toys.

“[T]hese battery cells may have exposed metal positive and negative terminals that can short-circuit when they come into contact with metal objects, such as keys or loose change in a pocket,” the agency wrote Friday. “Once shorted, loose cells can overheat and experience thermal runaway, igniting the cell’s internal materials and forcibly expelling burning contents, resulting in fires, explosions, serious injuries and even death.”

Injuries related to exploding 18650 cells have been documented for a few years now, but the frequency seems to have increased along with their availability on sites like Amazon or from wholesale retailers.

One of the companies that makes 18650 cells, LG Chem, asked distributors of e-cigarette equipment in a late 2018 letter to stop selling them, warning that “[i]ndividual consumer use and handling” that could “lead to severe burns and disfigurement,” according to a report in The Atlantic. Samsung and Sony also warn consumers against using the cells.

18650 cells are often used in more heavy-duty commercial settings, and even power Tesla’s Model X and Model S vehicles — though the CPSC acknowledges that’s fine, since it’s their intended use. That said, there is a small but growing DIY community springing up around building custom battery packs for e-bikes and even electric cars using 18650 cells bought on the internet.

Developing…