Heat Illness in the Workplace: A Growing Concern for Employers

As rising temperatures continue to impact workplaces across the United States, the issue of heat illness prevention has become increasingly critical for employers. A recent webinar presented by Sara Osorio, EHS Affairs Coordinator at PRINTING United Alliance, highlighted that this hazard is particularly acute in industries where employees are exposed to high heat, both indoors and outdoors.

During her presentation, Osorio shared that heat-related illnesses are now the second leading cause of weather-related fatalities in the U.S., contributing to over 2,000 fatalities, as well as 170,000 work-related injuries, and more than $100 billion in lost productivity attributed to heat illness. Because of this, she said, the urgency for clear regulatory standards and effective prevention measures cannot be overstated.

Federal Regulation: Still in Progress

Currently, the U.S. Occupational Safety and Health Administration (OSHA) has developed a proposed federal regulation for heat illness prevention, Osorio said, though it has yet to be finalized. While the Biden administration proposed the rule, its future remains uncertain, especially under the Trump administration, which may significantly alter or delay its implementation.

She said that despite the lack of a finalized federal rule, however, OSHA has taken action. In 2022, the agency launched a National Emphasis Program (NEP) to conduct targeted inspections in high-risk industries whenever the heat index reaches or exceeds 80°F, or when there is a complaint or reportable injury related to heat. The NEP, it should be noted, applies both indoor and outdoor workplaces.

OSHA can also cite employers under the General Duty Clause, which requires employers to provide a workplace free from recognized hazards. This includes excessive heat, even in the absence of a specific regulation. In order to issue a citation, OSHA must prove that the hazard exists, is recognized, can cause harm, and that feasible methods of abatement are available.

State Standards Take the Lead

In the absence of federal progress, many states have created their own heat illness prevention standards. Osorio provided a summary of current state-driven efforts:

California leads with comprehensive regulations for both indoor and outdoor workplaces, requiring written prevention plans, training, acclimatization protocols, and specific heat triggers (e.g., 80°F for outdoor, 82°F for indoor).

Oregon and Maryland have identical rules that take effect at 80°F, requiring access to water, shade, training, and rest breaks; additional requirements are triggered above 90°F.

Nevada’s rule takes a job hazard analysis approach rather than using fixed heat triggers. Under that approach, facilities with 10+ employees must evaluate job roles for heat risks and, if hazards are found, implement a heat illness prevention plan. Osorio shared that his flexible model is seen by some as a possible template for future federal regulations.

Washington applies its rules to outdoor work, with a low threshold of 52°F for workers in non-breathable clothing. Other workers fall under the standard at 80°F; mandatory rest breaks are required at 90°F. Minnesota, by contrast, targets indoor heat only, with thresholds tied to work intensity — 77°F for heavy work, 80°F for moderate, and 86°F for light. Ventilation and control measures are key requirements.

Risk Factors and Symptoms

Addressing risks, Osorio shared that while heat illness can affect anyone, certain environmental and personal factors increase the risk. Environmental factors can include air temperature, humidity, radiant heat, air movement, workload, and whether personal protective equipment is being used. Personal factors include age, weight, hydration, medical conditions, alcohol or caffeine use, and a lack of heat acclimatization.

Common conditions resulting from excessive heat exposure can include heat rash, heat cramps, fainting, heat exhaustion, and heat stroke. Heat stroke is a life-threatening emergency, which is characterized by hot, dry skin, confusion, and loss of consciousness. Immediate medical attention to heat stroke is essential.

Prevention Strategies

Even in the absence of a federal regulation, Osorio spoke to the need to understand and implement heat illness prevention strategies, and shared that effective heat illness prevention programs should include the following:

• Access to cool, potable water
• Shaded or air-conditioned rest areas close to work zones
• Work/rest schedules, especially in high heat
• Training on recognizing and responding to symptoms
• Emergency response procedures
• Acclimatization protocols for new or returning workers
• Monitoring the weather and employee conditions

It is important to note that even drivers must be protected. In this situation, air-conditioned vehicles can count as rest areas, and driver training is essential.

Moving Forward from Here

With heat-related illnesses on the rise and federal regulation still pending, employers must stay proactive. Osorio shared that understanding the risks, complying with applicable state rules, and implementing effective prevention measures can save lives, reduce liability, and protect productivity in a warming world.