What follows is an excerpt from the bulletin, “OSHA: Preventing Fire and/or Explosion Injury from Small and Wearable Lithium Battery Powered Devices” on the Occupational Safety and Health Administration (OSHA) website.
The excerpt outlines the hazards involved.
Please see the OSHA Safety and Health Information Bulletin in its entirety at the following OSHA web address:
Lithium batteries are generally safe and unlikely to fail, but only so long as there are no defects and the batteries are not damaged. When lithium batteries fail to operate safely or are damaged, they may present a fire and/or explosion hazard. Damage from improper use, storage, or charging may also cause lithium batteries to fail. Testing batteries, chargers, and associated equipment in accordance with an appropriate test standard (e.g., UL 2054). NRTL certification (where applicable), and product recalls, help identify defects in design, manufacturing, and material quality.
Damage to lithium batteries can occur immediately or over a period of time, from physical impact, exposure to certain temperatures, and/or improper charging.
- Physical impacts that can damage lithium batteries include dropping, crushing, and puncturing.
- Damage to all types of lithium batteries can occur when temperatures are too high (e.g., above 130°F). External heat sources (e.g., open flames, heaters, etc.) can also accelerate failure in cells with defects or damage from other causes.
- Damage to lithium-ion batteries can occur when the batteries themselves or the environment around the batteries is below freezing (32°F) during charging. Charging in temperatures below freezing can lead to permanent metallic lithium buildup (i.e., plating) on the anode, increasing the risk for failure.
- Charging a device or battery without following manufacturer’s instructions may cause damage to rechargeable lithium-ion batteries. For example, some manufacturer-authorized chargers will cycle the power to the battery on and off before it is fully charged to avoid overcharging. Since ultra-fast chargers may not cycle power, do not use them unless the manufacturer’s instructions include them as an option.
Heat released during cell failure can damage nearby cells, releasing more heat in a chain reaction known as a thermal runaway. The high energy density in lithium batteries makes them more susceptible to these reactions. Depending on the battery chemistry, size, design, component types, and amount of energy stored in the lithium cell, lithium cell failures can result in chemical and/or combustion reactions, which can also result in heat releases and/or over-pressurization.
- In chemical reactions, by-products from the electrolyte solution and electrodes can increase the pressure in the cell to the point where the cell walls expand and by-products leak out. Chemical by-products usually include carbon monoxide, carbon dioxide, hydrogen, and hydrocarbons. In many cases, the by-products are also combustible and could ignite.
- In combustion reactions, a thermal runaway releases byproducts that may ignite to cause smoke, heat, fire, and/or explosion. The by-products from a lithium battery combustion reaction are usually carbon dioxide and water vapor. In some lithium batteries, combustion can separate fluorine from lithium salts in the battery. If mixed with water vapors, fluorine may produce hydrofluoric acid, which is particularly hazardous because workers may not feel its effects until hours after skin exposure.
Ensure that an emergency action plan (EAP) for a workplace with lithium-powered devices or batteries includes lithium-related incident response procedures based on manufacturer’s instructions for responding to battery failures including fires and/or explosions.
Ensure that appropriate information about the hazards of lithium-powered devices and lithium batteries is communicated to exposed workers (e.g., during repair of lithium-powered devices or during recycling activities) and that workers receive training on the physical and health hazards associated with lithium-ion and/or lithium-metal cells or batteries.