Batteries: Lithium-ion Battery Safety Fact Sheet

FactSheet Lithium-ion Battery Safety Lithium-ion batteries are one type of rechargeable battery technology (other examples include sodium ion and solid state) that supplies power to many devices we use daily. In recent years, there has been a significant increase in the manufacturing and industrial use of these batteries due to their superior energy storage characteristics. This increased use of lithium-ion batteries in workplaces requires an increased understanding of the health and safety hazards associated with these devices.

The hazards and controls described below are important in facilities that manufacture lithium-ion batteries, items that include installation of lithium-ion batteries, energy storage facilities, and facilities that recycle lithium-ion batteries.

Lithium-ion Batteries A lithium-ion battery contains one or more lithium cells that are electrically connected. Like all batteries, lithium battery cells contain a positive electrode, a negative electrode, a separator, and an electrolyte solution. Atoms or molecules with a net electric charge (i.e., ions) are transferred from a positive electrode to a negative electrode through an electrolyte solution. Lithium cells store and release power by converting chemical potential energy into electrical energy using lithium ions or lithium metal. Electrolyte solutions allow ions to flow freely between the electrodes. There are several types of lithium cells, including cylindrical cells, prismatic pouch cells, and prismatic metal can cells. Chemical Hazards Lithium-ion batteries use lithium in ionic form Lithium-ion batteries contain various instead of in solid metallic form and are usually components that present different chemical rechargeable, often without needing to remove hazards to workers, such as flammability, the battery from the device. They power devices toxicity, corrosivity, and reactivity hazards. such as mobile telephones, laptop computers, These chemicals may enter the workplace as raw tablets, cameras, power tools, electric vehicles, materials or recycled materials. As processes and machinery, and are also used in large Energy change, any new chemicals must be thoroughly Storage Systems (ESS). assessed for potential safety and health impacts to the workplace and workers. Potential Hazards A lithium-ion battery cathode is made of a Lithium-ion batteries may present several health lithium metal oxide material. The choice of and safety hazards during manufacturing, use, cathode material depends on the desired emergency response, disposal, and recycling. characteristic of the battery. These materials can These hazards can be associated with the include lithium cobalt oxide (LiCoO2), lithium chemicals used in the manufacture of battery manganese oxide (LiMn2O4), lithium nickel cells, stored electrical energy, and hazards created manganese cobalt oxide (LiNiMnCoO2), lithium during thermal runaway, (see below) which can nickel cobalt aluminum oxide (LiNiCoAlO2), or include fire, explosions, and chemical byproducts. lithium iron phosphate (LiFePO4).

Common materials for a lithium-ion battery Safety Hazards anode include carbon-based materials such In addition to electrical hazards, lithium-ion as graphene, nanofibers, carbon nanotubes, batteries can also present hazards resulting graphite, and titanium-based materials such as from thermal runaway. Because lithium-ion lithium titanate and titanium dioxide. batteries combine a flammable electrolyte with a significant amount of stored energy, thermal Lithium-ion batteries contain electrolytes runaway reactions are possible. Thermal runaway that are a combination of solvents with an is a chain reaction where the heat released from electrolytic salt. Lithium hexafluorophosphate, the failure of one cell damages nearby cells. This the most common salt used in lithium-ion cells, can be initiated by internal short circuiting due can react with water to form hydrogen fluoride to defects during manufacturing, mechanical (HF). The most common solvents used in damage to the battery, exposure to excessive lithium-ion batteries include ethylene carbonate heat or cold, and improper charging. (EC), propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate Thermal runaway can be identified by (EMC), and diethyl carbonate (DEC). Some of several indicators including a rise in battery these electrolytes are flammable liquids and temperature, venting of gas, vapor, or smoke requirements within OSHA’s Process Safety from the battery, or the presence of fire. Fires Management standard may apply to quantities caused by thermal runaway can produce exceeding 10,000 lb. additional chemical hazards that may include hydrogen fluoride (HF), hydrogen chloride (HCl), Many of the chemicals used in lithium-ion hydrogen cyanide (HCN), phosphoryl fluoride battery manufacturing have been introduced (POF3), carbon monoxide (CO), carbon dioxide relatively recently. Consequently, there may (CO2), black carbon, and other potentially be limited toxicological information and few hazardous chemicals and particulates. established OSHA permissible exposure limits (PELs). Additionally, because some of For additional information see OSHA’s Safety OSHA’s PELs may be outdated and inadequate and Health Information Bulletin on Preventing for protecting worker health, employers Fire and/or Explosion Injury from Small and should consider alternative occupational Wearable Lithium Battery Powered Devices. exposure limits (OELs) developed by technical, professional, industrial and/or government Safety by Design organizations to ensure worker protection. For Whether manufacturing or using lithium- chemicals without occupational exposure limits, ion batteries, anticipating and designing out Occupational Exposure Banding and Control workplace hazards early in a process adoption Banding can be used with the Hierarchy of or a process change is one of the best ways to Controls to manage risks and prevent exposure prevent injuries and illnesses. Hazard controls to hazardous chemicals. See the NIOSH Control must be addressed in the initial design and Banding webpage and the OSHA Permissible construction phases, as well as implemented Exposure Limits – Annotated Tables for through changes to management and additional information and explanation. manufacturing processes as production methods Additionally, when a lithium-ion battery or cell and energy storage technologies evolve. Safety does not meet exemptions under OSHA’s Hazard by design includes the proactive substitution and Communication Standard (HCS) as an “article,” adoption of less hazardous technologies. See the the manufacturer or importer is required to NIOSH webpage, Prevention through Design, for classify the chemical hazards and provide the additional information. hazard information to downstream users. For Safety and Health Management System additional information, see OSHA’s Letters of Interpretation regarding the Coverage of lithium- Establishing a safety and health management ion batteries under the Hazard Communications system (SHMS) (i.e., safety program) is an Standard (6/23/2021) and Applicability of the effective way of protecting workers from HCS to Lithium-ion Batteries (12/1/2022). potential hazards associated with lithium-ion

batteries. A mature and effective SHMS can • Disposing of lithium-ion batteries and devices prevent workplace injuries and illnesses by containing these batteries, at designated using proactive approaches to find and fix recycling facilities and not placing them in workplace hazards before they cause injury and municipal trash or recycling bins illness to workers. To be effective, the SHMS • Not mixing battery types (e.g. lithium-ion, must have meaningful worker engagement alkaline, lead acid) in recycling facilities and participation. In many workplaces, worker • Providing safety showers and eyewash participation may include a safety committee stations in locations where exposure to that can bring workers and management electrolytes may occur together to identify and find solutions, and • Developing and implementing an emergency to promote safety and health. See the OSHA response plan, including emergency webpage Recommended Practices for Safety and procedures, and creating training for Health Programs for additional information on response personnel that addresses possible implementing a successful SHMS or program. physical and chemical hazards, including hazardous decomposition products (e.g., Hazard Controls hydrogen fluoride) Lithium-ion battery hazard controls should • Conducting a hazard assessment and using be implemented according to the Hierarchy proper personal protective equipment (PPE), of Controls. Controlling hazards at the source when appropriate is the most effective method to eliminate or reduce hazards. . OSHA’s Transitioning to Safer Training Chemicals Toolkit is a step-by-step resource with Education and training are important tools information, methods, tools, and guidance for for informing workers and managers about employers and workers to proactively reduce or workplace hazards and controls. Workers eliminate chemical hazards at the source through must be trained in a language and at a literacy informed substitution. level they understand. Appropriate training may include, but is not limited to, Hazard Additionally, hazard controls that can be Communication (29 CFR 1910.1200) training, implemented in workplaces that manufacture or Hazardous Waste Operations and Emergency use lithium-ion batteries include: Response (HAZWOPER) (29 CFR 1910.120) • Ventilation, including local exhaust ventilation training, and Process Safety Management (29 (LEV) and enclosures CFR 1910.119) training . OSHA’s publication • Process automation and isolation of Training Requirements in OSHA Standards hazardous materials provides a general overview of the training • Storage of lithium-ion batteries and devices in requirements in specific OSHA standards. dry, cool locations In workplaces with lithium-ion batteries, it • Following National Fire Protection Association is important that employers ensure that an (NFPA) guidance for the installation of Energy emergency action plan (EAP) includes lithium- Storage Systems related incident response procedures based • Following manufacturer’s instructions for on the manufacturer’s instructions and NFPA storage, use, charging, and maintenance of guidance for responding to battery failures, lithium-ion batteries including fires and/or explosions caused by • Limiting the quantity of stored lithium-ion thermal runaway, and that workers are trained batteries on these procedures. • Following the manufacturer’s guidance on how to extinguish small battery fires For workplaces involved in the manufacturing, • Continuous monitoring for flammable and repair, use, and recycling of lithium-ion toxic gases in large storage locations batteries, it is important for employers to ensure • Using shipping guidance provided by the that exposed workers receive appropriate US Department of Transportation and information about the hazards associated with International Air Transport Association (IATA) lithium-ion batteries and that workers receive and following proper shipping and packaging training on the physical and health hazards requirements provided in 49 CFR 173.185 associated them.

OSHA Standards Consensus/Industry Standards While there is not a specific OSHA standard and Programs for lithium-ion batteries, many of the OSHA • National Fire Protection Association, NFPA general industry standards may apply, as well 855 Standard for the Installation of Stationary as the General Duty Clause (Section 5(a)(1) Energy Storage Systems of the Occupational Safety and Health Act of • International Electrotechnical Commission, 1970). These include, but are not limited to the IEC 62281 Safety of Primary and Secondary following standards: Lithium Cells and Batteries During Transport • Underwriters Laboratories, UL 2054 Standard • 1910 Subpart L - Fire Protection for Household and Commercial Batteries • 1910 Subpart S - Electrical • Underwriters Laboratories, UL 9540 Standard • 1910.39 Fire Prevention Plans for Energy Storage Systems and Equipment • 1910.119 Process Safety Management of • The American Society of Safety Professionals, Highly Hazardous Chemicals ANSI/ASSP Z10.0 Occupational Health and • 1910.120 Hazardous Waste Operation and Safety Management Systems Emergency Response • International Organization for Standardization, • 1910.132 Personal Protective Equipment ISO 45001 Occupational Health and Safety • 1910.134 Respiratory Protection Management Systems • 1910.147 The Control of Hazardous Energy (Lockout/Tagout) How to Contact OSHA • 1910.151 Medical Services and First Aid OSHA’s mission is to assure America’s workers • 1910.178 Powered Industrial Trucks have safe and healthful working conditions free • 1910.1000 Air Contaminants from unlawful retaliation. For more information, • 1910.1020 Access to employee exposure and visit www.osha.gov or call OSHA at 1-800-321- medical records OSHA (6742), TTY 1-877-889-5627. • 1910.1200 Hazard Communication

These standards are also representative of the types of protections that apply to the manufacture and use of other energy storage technology, whether in use now or under development.

This is one in a series of informational fact sheets highlighting OSHA programs, policies or standards. It does not impose any new compliance requirements. For a comprehensive list of compliance requirements of OSHA standards or regulations, refer to Title 29 of the Code of Federal Regulations. This information will be made available to sensory-impaired individuals upon request. The voice phone is (202) 693-1999; teletypewriter (TTY) number: (877) 889-5627.

DTSEM FS-4480 01/2025