According to the Bureau of Labor Statistics, 479 workers in the United States died from exposure to environmental heat between 2011 to 2022 – an average of 40 fatalities per year. The Occupational Safety & Health Administration (OSHA) states that 50-70% of the outdoor fatalities occur in the first few days of working in warm or hot environments, because the body is not acclimatized to the heat.1

Climate change has intensified heat risks for workers, leading to increased heat-related illnesses and deaths – especially in physically demanding jobs in extreme conditions.2 More than 70% of the global workforce is at risk from severe heat. As the climate changes, average and extreme temperatures are increasing, along with heat waves.3

To address this, OSHA issued a new federal standard for Heat Injury and Illness Prevention, which was proposed on August 30, 2024 and passed the comment period ending January 14, 2025. The American Industrial Hygienist Association (AIHA) commented with their recommendations on the proposed standard on November 5, 2024.

OSHA is looking to finalize the new rule to help prevent workplace heat-related injuries and illnesses in both indoor and outdoor environments and has scheduled a virtual public hearing on June 16, 2025. This hearing will allow stakeholders to present their views and suggestions directly to OSHA, further informing them of the development of the final rule. It applies to construction, general industry, maritime, and agriculture sectors, unless subject to an exception (i.e., work where employees are unlikely to be exposed to extended high-heat conditions, like in an air-conditioned office).

State-Mandated Heat Illness Prevention Requirements

Currently, OSHA can enforce heat-related hazards under the General Duty clause which requires employers to provide a workplace free from recognized hazards that are likely to cause death or serious harm. California, Maryland, Washington, Oregon, Nevada, Minnesota, Colorado and New York have already adopted heat-related regulatory standards to protect workers. Other states, like Texas and Virginia, provide recommended guidelines for preventing worker heat injury and illness. On the next page we present a comparison between the key requirements in the new proposed OSHA Standard for Heat Injury and Illness Prevention and current state mandates.

HETI Industrial Hygiene Services

HETI has Certified Industrial Hygienists across the U.S. available to help clients navigate through heat injury and illness prevention issues, including compliance. We have extensive experience in Heat Injury and Illness Plan (HIIP) development, heat monitoring techniques, risk assessments, emergency response procedures, and employee training experience – with a variety of industries, including manufacturing, oil and gas, and government.

References:
1OSHA – Overview: Working in Outdoor and indoor Heat Environments
2OSHA – Heat Injury and Illness Prevention in Outdoor and Indoor Work Settings Rulemaking
3 EPA – Climate Change and the Health of Workers
4 https://www.bdlaw.com/publications/osha-proposes-new-heat-injury-and-illness-prevention-standard/
5Trump Administration’s ‘Regulatory Freeze Pending Review’ Pauses OSHA’s Rulemaking on Heat Illness and
Emergency Response

6“Chill For Now”—Trump Administration Pauses Heat Hazard Rule, But Contractors Still Face Compliance Issues
7California Indoor Heat Protections approved to go into effect
8R131-24
9MNOSHA Heat Stress Guide
10 HOUSE BILL 25-1286
11 S1604C

To find out more about this and other HETI industrial hygiene services, please contact us.
Renee Cowell, CIH, CSP
Senior Industrial Hygienist
Phone: 978.263.4044
development@hetiservices.com
HETI at AIHA CONNECT 2025
Meet the HETI team at Booth #734 during the American Industrial Hygiene Association
Annual Conference & Expo, May 19-21 in Kansas City, Missouri
HETI’s Dr. Daniel Farcas, CIH, CSP, CHMM will teach the course,
PDC 406: CIH Exam Equations Visually Explained,
on Sunday, May 18 from 8:00 AM to 5:00 PM
at the Kansas City Convention Center, Room 2101

Lithium-ion batteries have revolutionized consumer electronics and motor vehicles and have contributed to the enhancement of renewable energy storage. These batteries are used globally every day to power laptops, cell phones, power tools, e-bikes, hoverboards and portable devices – such as forklifts and pallet jacks. Today in China, there are more than 350 million electric motorcycles and e-bikes in use, representing the single largest sector of motor vehicles.

Why have lithium-ion batteries become so popular? They have a higher power density than traditional batteries. They are inexpensive to produce, charge quickly, and hold a charge for a longer period of time. And they have a longer life – able to go through up to 1,000 charging cycles.

As widespread as their use is, lithium-ion batteries have a very short history. The first commercially available battery was introduced in the Sony Handi-Cam in 1991 and the first automotive battery was the Tesla Roadster in 2008. Yet the concept of a lithium-ion battery nearly ended in the 1980s when the world had no interest in a rechargeable battery

In this edition of HETI Horizons, we will explore the composition and structure of lithium-ion batteries and how they should be handled to prevent uncontrolled fires that burn intensely and at very high temperatures. Most suburban and rural fire departments are poorly trained or equipped to fight lithium battery fires.

How Do Lithium-Ion Batteries Work?

Rechargeable batteries are composed of an anode and a cathode. Lithium-ion batteries store a lithium electrolyte salt solution and two current collectors (positive and negative). When the battery is discharging, providing current, the anode releases lithium ions which travel through the electrolyte to the cathode. When charging, the opposite happens.

Why Are Lithium-Ion Batteries Dangerous

Lithium-ion batteries pose fire and explosion hazards when they are misused or damaged. The electrolyte-rich fluid, which allows the battery to store a lot of energy, is both volatile and flammable. Most fires result from cell failure when exposed to high temperatures. When one cell fails and ignites, it causes a condition known as thermal runaway – where all cells ignite until all of the fuel is consumed.

The heat from a battery fire can reach temperatures as high as 1,000 degrees Fahrenheit in a matter of seconds – resulting in significant structural damage when the fire is in an enclosed space. A lithium-ion battery fire can cause the release of toxic chemicals such as hydrogen fluoride and hydrogen chloride. In an uncontrolled battery failure, the resulting fire may be hard to contain and can easily hold enough heat to reignite. The Consumer Product Safety Commission reported that during the five-year period of 2017-2022 there were more than 25,000 overheating or fire incidents involving over 400 types of lithium batteries.

The mechanisms that cause, and the consequences of, battery failure are not well understood. Studies indicate that 80% of fires are caused by electrical damage – typically a result of cell failure, overcharging, and mismatched batteries/chargers sold online as replacements. About 10% stem from physical damage – such as dropping or striking a battery. The remaining fires result from manufacturing defect.

Fighting a fire involving a lithium-ion battery is difficult. Due to the elevated temperature of these fires, the use of a portable fire extinguisher is typically not effective. The best response is to contact the fire department and let them know the fire involves a device with a lithium-ion battery. Since the battery does not contain lithium metal, explosion hazard is not the primary risk. The key is to lower the temperature at the source of the fire as quickly as possible with a water spray. This can cool the battery to help prevent the spread of the fire but will not extinguish the fire until the fuel is consumed. There are specialized products such as F-500 which forms a thin layer around the fuel molecules preventing oxygen from reaching the fuel. F-500 portable extinguishers are commercially available for Class D fires, which may be a consideration for commercial properties that have portable devices with lithium-ion batteries. However, at this point, fire departments are unlikely to carry this equipment on their vehicles.

Lithium-Ion Battery Safety

Correct storage and use of lithium-ion batteries are very important. Batteries should be protected from extremes in temperature during charging, since overcharging can create excessive heat inside a battery. It is important to use a quality charger recommended by the equipment manufacturer – designed to control the amount of charge to go into a battery cell and to shut off the charger when fully charged. Charging when a building is not occupied is not recommended unless there is a timer on the circuit. Chargers purchased online that are not labeled or certified are not recommended.

Underwriters Laboratories is proposing a standard, UL1487, for battery containment enclosures – designed to limit fire spread in the event of a cell failure. Other applicable standards include UL 2272 “Systems for Personal E-Mobility Devices” and UL2849 “Standard for Safety for Electrical Systems on E-Bikes”. There are also lithium-ion battery management systems that can be utilized to track battery temperature, cell voltage and cell charge. Heat, smoke, swelling or popping sounds may be early warning signs of impending cell failure – indicating the device should be isolated, if possible, taking care to protect the safety of occupants.

HETI: Helping Bring Safe Battery Management to the Workplace

HETI can provide training on lithium-ion battery safety, assist with the selection of portable fire extinguishers, set up training programs for device management, and offer guidance on proper disposal of end-of-life batteries and chargers.

For further information on HETI’s environmental health & safety services, please contact us.
Scott Herzog, CIH and Theresa Butziger, LPG