Heat Stress Is Reshaping Protective Apparel Programs
As OSHA advances a federal heat rule and temperatures continue to climb, safety professionals are reevaluating how FR and FR/AR clothing affects worker comfort, compliance and physiological strain.
- By David Kopf
- Jun 18, 2026
For decades, flame-resistant (FR) and arc-rated (FR/AR) clothing has been viewed primarily through the lens of catastrophic injury prevention. In industries where flash fires, arc flashes and combustible hazards are part of the job, protective apparel serves a critical purpose: helping workers survive incidents that can unfold in fractions of a second.
But as temperatures rise and heat stress receives growing regulatory scrutiny, safety professionals are increasingly confronting another reality about FR apparel programs: the garments designed to protect workers can also contribute to heat strain, fatigue and reduced worker tolerance in hot environments.
That challenge is becoming harder to ignore. Heat-related illnesses and injuries continue to affect thousands of workers annually, while employers prepare for OSHA’s proposed Heat Injury and Illness Prevention rule, which would establish formal federal requirements for managing occupational heat exposure.
For employers whose workers already wear layered or heavy FR/AR apparel, the issue is especially complex. Protective clothing remains essential for preventing severe burn injuries, but organizations are increasingly under pressure to reduce overall heat burden and improve worker comfort during long shifts in high-temperature conditions.
As a result, FR and FR/AR apparel programs are beginning to evolve. While protection standards remain non-negotiable, manufacturers and safety leaders are placing greater emphasis on breathability, mobility and physiological comfort. Increasingly, safety professionals are recognizing that comfort is not simply a quality-of-life issue; it is directly tied to compliance, worker behavior and overall safety performance.
Why FR and FR/AR Clothing Matters
FR clothing is designed to self-extinguish and minimize burn injuries when exposed to flames or thermal events. Arc-rated apparel provides additional protection against the intense thermal energy generated during an electrical arc flash. Depending on the work environment, these garments may include shirts, pants, coveralls, outerwear and base layers.
Workers across utilities, oil and gas, electrical work, manufacturing and heavy industry rely on this protection every day. In many cases, FR or FR/AR requirements are driven by OSHA regulations, NFPA 70E guidance or employer hazard assessments.
Because of these hazards, employers have historically prioritized protection performance above nearly every other factor. Garments were selected based on arc ratings, flame resistance and durability. Comfort and wearability often came later in the conversation.
Today, however, many safety professionals are recognizing that uncomfortable PPE can create secondary risks of its own.
The Heat Burden Challenge
Traditional FR garments have long been associated with thicker fabrics, limited airflow and additional heat retention. In hot environments or physically demanding jobs, workers wearing layered protective clothing may experience substantial physiological strain over the course of a shift.
That burden becomes especially significant during summer months, in southern climates, or in industrial environments where workers are already exposed to radiant heat or poor ventilation.
The effects can include dehydration, fatigue, reduced concentration and diminished productivity. In more serious cases, workers may experience heat exhaustion or heat stroke.
Heat illness continues to represent a major occupational concern. Federal data shows environmental heat exposure kills dozens of U.S. workers annually and contributes to thousands of workplace illnesses and injuries each year. Safety experts also note that heat stress can indirectly contribute to additional incidents by impairing concentration, slowing reaction times and increasing the likelihood of mistakes.
Importantly, OSHA’s proposed heat rule applies to both indoor and outdoor workplaces, recognizing that manufacturing facilities, warehouses and industrial operations may expose workers to dangerous temperatures as well.
For organizations requiring FR/AR apparel, the challenge extends beyond heat illness alone. Uncomfortable protective clothing can also create compliance problems. Workers attempting to cool down may roll sleeves, remove layers or otherwise wear garments improperly. Even seemingly minor modifications can reduce protective effectiveness during a flash fire or arc flash incident.
Increasingly, employers recognize that workers are more likely to wear PPE consistently and correctly when garments reduce heat burden and allow greater comfort and mobility.
OSHA’s Heat Rule Raises the Stakes
In August 2024, OSHA released a proposed Heat Injury and Illness Prevention rule that would establish the first comprehensive federal standard specifically addressing occupational heat hazards.
If finalized, the rule would require employers to develop formal heat illness prevention plans and implement controls when workplace temperatures reach designated heat index thresholds.
Under the proposal, employers would need to provide water, rest breaks and shaded or cooled recovery areas beginning at an 80-degree Fahrenheit heat index. Additional protections would activate at higher temperatures, including enhanced monitoring and increased supervisory oversight.
The proposal also includes requirements related to:
- acclimatization procedures
- employee and supervisor training
- emergency response planning
- heat hazard assessments
- written prevention programs
OSHA estimates the rule could affect approximately 36 million workers nationwide.
The agency held hearings and stakeholder sessions throughout 2025 and is now reviewing testimony and industry feedback before determining the next phase of the rulemaking process. Even before a final standard is issued, OSHA has continued emphasizing heat-related enforcement through its National Emphasis Program and the General Duty Clause.
For safety professionals overseeing FR apparel programs, that means protective clothing itself is becoming part of the heat stress conversation.
How FR Apparel Is Beginning to Change
In response, manufacturers and textile developers are increasingly focusing on reducing physiological strain while maintaining required protection levels.
One of the most visible developments involves lighter-weight fabrics. Historically, many FR garments relied on heavier materials that could trap heat and restrict airflow. Newer fabrics are being engineered to reduce overall garment weight while still meeting required thermal and arc protection standards.
Moisture management has also become a major focus. Many modern FR fabrics are designed to improve sweat evaporation and move moisture away from the skin more efficiently. Improved breathability may help workers remain cooler during physically demanding tasks.
Garment construction is evolving as well. Stretch FR fabrics, ergonomic patterning and improved mobility features can reduce restriction and improve range of motion. In some environments, employers are also reevaluating layering strategies to balance protection with worker tolerance under changing environmental conditions.
Importantly, however, safety professionals must remember that cooler does not automatically mean safer.
Hazard assessments remain critical. Protective apparel must still be selected based on the specific thermal, electrical or combustible hazards associated with the job task.
Comfort as a Safety Issue
One of the most important changes occurring within the PPE industry is the growing recognition that comfort itself influences safety outcomes.
Workers experiencing heat strain and fatigue may become distracted, make poor decisions or lose focus during high-risk tasks. In environments involving energized equipment or combustible hazards, even small mistakes can carry severe consequences.
Comfort also affects compliance. Workers are more likely to wear protective apparel properly and consistently when garments fit correctly, allow movement and reduce heat burden.
Rather than treating comfort as secondary to protection, many organizations are beginning to view wearability as part of a broader risk reduction strategy.
What Safety Leaders Should Do Next
For safety managers and EHS leaders, the growing intersection between heat stress and FR apparel presents an opportunity to reevaluate PPE programs more holistically.
First, organizations should revisit hazard assessments to ensure apparel requirements align with both operational risks and environmental realities. Heat burden should be considered alongside thermal and electrical hazards during PPE evaluations.
Second, employers should involve workers directly in garment selection and wear trials. Employees who wear FR apparel daily often provide valuable feedback regarding mobility, layering challenges, comfort and usability during real-world conditions.
Organizations should also begin preparing now for the likely direction of OSHA’s heat stress standard. Many of the proposed requirements — including acclimatization planning, training programs and documented heat illness prevention procedures — already reflect emerging best practices.
Finally, safety professionals should remember that effective FR programs depend on more than compliance labels alone. The most effective apparel programs increasingly balance protection, wearability and worker acceptance together.
FR and FR/AR clothing will always serve a critical role in protecting workers from catastrophic hazards. But as heat stress concerns continue to intensify, the conversation surrounding protective apparel is changing.
The goal is no longer simply ensuring workers are protected during an emergency event. Increasingly, the goal is ensuring workers can safely and consistently wear that protection throughout an entire shift — even in some of the hottest and most physically demanding environments they may face.
This article originally appeared in the issue of Occupational Health & Safety.