7 Best Practices for Managing Heat Stress in Indoor Work Environments

Heat-related injury and illness are occupational hazards that impact many industries and affect millions of employees annually. Heat stress occurs when an individual’s body accumulates more heat than it can dissipate. The increase in body temperature can result from several factors, including metabolic heat from physical exertion, workplace conditions, and clothing or personal protective equipment (PPE) that make it difficult to release heat from the body. Indoor work environments can create hot atmospheric conditions similar to outdoor environments and, in some cases, exceed outdoor temperatures. Types of heat-related illnesses include heat stroke, heat exhaustion, rhabdomyolysis, heat syncope, and heat-related cramps and rashes.

Industries commonly associated with indoor heat exposure include, but are not limited to, commercial kitchens, manufacturing, warehousing, laundry and dry-cleaning services, and greenhouses. Industrial equipment, ovens and furnaces generate significant heat within enclosed spaces, and solar radiation striking a facility’s roof and walls can push interior temperatures to dangerous levels. High humidity amplifies the heat index, and poor ventilation makes cooling work areas difficult. Without adequate airflow, access to hydration, and air-conditioned break areas, these environments can become dangerously hot.

Beyond the human cost, employers face real regulatory exposure. While a permanent federal heat standard remains uncertain under the current administration, OSHA’s National Emphasis Program on heat-related hazards has been extended through April 2031, and several states, including California, Minnesota, Oregon and Maryland, have already adopted their own indoor heat illness prevention standards. Regardless of where federal rulemaking lands, OSHA can and does cite employers under the General Duty Clause for failing to protect workers from heat hazards.

The good news is that heat-related injury and illness are largely preventable and, with strong controls and procedures in place, can be managed in your operation. Consider these seven best practices to manage heat stress in your workplace.

1. Implement a Heat-related Injury and Illness Prevention Program

 

Developing a formal indoor heat-related injury and illness prevention program is a best practice, and for many organizations, simply taking the time to establish one is a significant step forward. A structured program signals a genuine organizational commitment to employee safety and can provide several tangible benefits, including preventing heat-related injuries and illnesses, reducing workers’ compensation claims, lowering absenteeism and turnover, and maintaining a productive workforce. Employees who see their organization actively working to keep them safe tend to be more engaged, loyal and productive.

Because indoor work environments vary widely, the program should be tailored to your specific operation, accounting for your facility’s characteristics, the nature of the work performed, and the types of heat relief available to employees. A one-size-fits-all approach is unlikely to address the real conditions your workforce faces. Once developed, formalizing the program in writing and communicating it directly to employees ensures that everyone understands the practices in place and knows what to do when heat-related risks arise. New employees should be made aware of heat-related hazards and the various reliefs during orientation, and experienced employees should be reminded annually. Consider delivering heat-awareness training in the spring, before the hotter months arrive, so the information stays fresh when employees need it most.

A well-built program is the foundation, but it only delivers results when supported by consistent, day-to-day practices. The remaining six best practices outlined in this document support the program’s mission.

2.     Monitor and Record Temperature

Consistent temperature monitoring is your first line of defense in identifying when and where employees face elevated risk. Effective heat management starts with accurate data. Place thermometers in the hottest work areas of your facility and at multiple points throughout. An option to consider is Wi-Fi-enabled thermometers, which allow supervisors to monitor conditions in real time from laptops, tablets or smartphones, enabling faster response when temperatures climb.

Use heat index readings rather than raw temperature alone. The heat index accounts for humidity and better reflects what workers actually experience, making it a more reliable trigger for interventions such as work-rest cycles, job rotations or temporary work stoppages. Establish clear internal thresholds, such as action levels tied to heat index ranges, so supervisors know when to intervene and employees know what to expect.

3.     Establish a Work-rest Cycle to Reduce Excessive Heat Exposure

Effective work-rest cycles are driven by two key factors: the heat index in the work area and the intensity of work being performed. Work intensity is generally classified as light, moderate or heavy. While no regulatory standard exists for work-rest cycles, the National Institute for Occupational Safety and Health (NIOSH) provides general guidance as a useful starting point, though applicability will vary by operation. For more information, refer to NIOSH’s work-rest cycle guidance.

If work-rest cycles are not feasible within your operation (or required within your state), job rotation is an effective alternative. Limit prolonged exposure to the hottest areas of your facility by rotating employees throughout the shift. In facilities with more uniform temperatures, consider rotating job tasks by light, moderate or heavy classifications to manage overall physical strain.

4.     Make Hydration Stations Readily Available

Maintaining adequate hydration is critical to preventing heat-related injury and illness. Provide designated hydration stations stocked with water and electrolyte replenishment options, such as sports drinks or electrolyte packets. Replacing lost fluids and electrolytes supports healthy blood volume, circulation and the body’s ability to regulate temperature through sweating.

Even mild dehydration can impair judgment, coordination and work performance, increasing the risk of both heat illness and workplace incidents. Ensure fluids are consistently accessible throughout your facility, particularly during warmer months, to safeguard employee health and sustain operational productivity.

Equally important is actively encouraging employees to hydrate regularly. Workers may delay drinking fluids due to workload demands, habits or simply because they do not recognize early signs of dehydration. Supervisors play a key role here: building hydration reminders into shift routines, toolbox talks or team check-ins help reinforce the message and normalize taking breaks before thirst sets in. A workforce that is reminded and empowered to stay hydrated is better protected and more productive.

5.     Provide Cooling PPE

Cooling PPE is an effective way to reduce the risk of heat-related illness and can be tailored to your operation’s specific needs. When selecting cooling PPE, consider both the temperature conditions within your facility and the physical intensity of the work being performed, as these factors will determine the most appropriate and cost-effective solutions.

Available options include, but are not limited to:

• Cooling towels and bandanas—Lightweight, low-cost options suitable for general heat relief
• Moisture-wicking base layers—Help manage perspiration and maintain comfort during prolonged physical activity
• Ice/gel cooling vests—Provide active cooling for workers in high-heat environments or performing heavy work
• Cooling sleeves—Offer targeted protection for the arms while maintaining freedom of movement

Evaluating your facility’s specific heat hazards will help ensure the selected PPE provides meaningful protection while remaining practical for day-to-day operations.

6.     Make Climate-controlled Break Rooms Accessible

Access to climate-controlled rest areas is an essential component of an effective heat management program. Providing a cool environment during breaks allows the body to dissipate heat and restore a healthy core temperature, reducing cumulative heat stress throughout a shift.

In high-heat work environments, climate-controlled rest areas should be accessible during every work-rest cycle. They should ideally be located close to work areas so employees can reach them quickly without their rest time being consumed by travel. Consistent access to cool recovery spaces reduces the risk of heat exhaustion and allows employees to return to work refreshed and alert.

7.     Develop an Acclimatization Period for New Hires and Returning Workers

Heat acclimatization is the gradual introduction of employees to heat exposure, allowing their bodies to physiologically adapt over time. It is particularly important for new hires who have not yet developed the heat tolerance required by their role, but it is not exclusive to them. Employees returning from extended absences due to illness, vacation or leave should undergo a similar reintroduction process, as heat tolerance can diminish after just a few days away from the work environment.

As with work-rest cycles, NIOSH and the Centers for Disease Control and Prevention provide a recommended acclimatization schedule to guide this process. While applicability may vary by operation, it serves as a practical framework for reducing risk during the adjustment period. For more information, refer to the NIOSH acclimatization schedule.

Take Action

Heat-related injury and illness are serious occupational hazards, but with the right program in place, they are largely preventable. By monitoring temperatures, establishing work-rest cycles, maintaining hydration stations, providing cooling PPE, ensuring access to climate-controlled rest areas, and implementing acclimatization protocols, organizations can meaningfully reduce the risk of heat-related harm to their workforce. Start by evaluating your current practices against these seven best practices and take the necessary steps to build a safer, healthier work environment for everyone in your facility.

Article Published By: Zywave, Inc.