What Happened

A new OSHA letter of interpretation is raising important questions for employers across every industry: if an employee's personal lithium-ion batteries malfunction at work and cause a burn injury, can it be classified as a work-related incident?

According to the January 20, 2026 guidance, the answer may be yes.

The letter examines a specific scenario involving an employee who brought e-cigarette batteries to their workplace. The batteries malfunctioned, causing burn injuries to the worker. OSHA's interpretation provides guidance on when such injuries must be recorded in an employer's OSHA 300 log.

When Personal Battery Burns Are Work-Related

Under OSHA's guidance, burn injuries from personal lithium-ion devices may be classified as work-related when:

• The injury occurs during work hours
• The incident happens on company premises
• A direct connection exists between the workplace environment and the battery malfunction — for example, if workplace conditions such as heat exposure contributed to the battery failure

This means that even though the device is personal property, the employer may still need to record the injury if the nexus between the workplace and the incident can be established.

Why This Matters for Employers

Lithium-ion batteries are everywhere in the modern workplace. Employees carry smartphones, smartwatches, e-cigarettes, portable chargers, and other personal devices that use lithium-ion cells. While catastrophic failures are rare, they do happen — and when they happen at work, employers need to know their recording obligations.

The key implications:

• OSHA 300 log recording — If the injury meets the work-relatedness criteria, it must be recorded even though the device is personal property
• Workplace policy considerations — Employers may want to review policies about personal electronic devices, especially in environments with heat, moisture, or chemical exposure that could affect battery stability
• Training — Workers should understand basic lithium-ion battery safety, including signs of swelling, overheating, or damage that indicate a battery should be replaced

Lithium-Ion Battery Safety Basics

Lithium-ion batteries fail for several reasons, many of which can be exacerbated by workplace conditions:

• Thermal exposure — High ambient temperatures or proximity to heat sources accelerate battery degradation and increase failure risk
• Physical damage — Drops, crushing, or puncture can compromise the battery's internal separator, leading to short circuits
• Chemical exposure — Contact with certain chemicals can corrode battery casings or connections
• Overcharging or use of incompatible chargers — Particularly relevant for e-cigarette batteries, which may use non-standard charging systems

When a lithium-ion battery enters thermal runaway, temperatures can exceed 500°C (932°F) and the cell can vent flammable electrolyte gases. Having proper first aid and fire suppression equipment accessible in the workplace is essential.

What Employers Should Do

• Review your OSHA 300 log procedures — Ensure your recordkeeping process accounts for injuries from personal devices
• Assess workplace conditions — Identify areas with elevated temperature, chemical exposure, or physical hazards that could affect battery safety
• Update safety training — Include lithium-ion battery hazards in your workplace safety orientation, especially in manufacturing, laboratory, and chemical handling environments
• Maintain first aid supplies — Ensure burn treatment supplies are accessible, and consider adding a Class D fire extinguisher in areas where lithium battery fires could occur