Summer has a way of arriving all at once: longer days, vacation schedules, iced coffee orders, and the familiar hum of air conditioners working overtime. But for employers, warmer weather also brings a less refreshing seasonal concern: heat stress. Whether employees are working on construction sites, in agricultural fields, on loading docks, in commercial kitchens, in warehouses, or near heat-generating equipment indoors, employers should be prepared to identify and control heat-related hazards before they become medical emergencies, compliance problems, or both.

Federal landscape

At the federal level, as most employers know, the Occupational Safety and Health Administration (OSHA) does not currently have a specific heat stress standard for indoor or outdoor heat-related hazards. That does not mean, however, that heat-related hazards fall outside OSHA’s enforcement authority. OSHA may cite employers under the General Duty Clause of the Occupational Safety and Health Act, which requires employers to provide a workplace free from recognized hazards that are causing or are likely to cause death or serious physical harm.

Heat stress also remains an OSHA enforcement priority. The agency has used local, regional, and national emphasis programs to target inspections and enforcement in industries and worksites where employees may face elevated risks of heat-related illness. Employers in high-risk industries like manufacturing, warehousing, kitchens, construction, agriculture and landscaping, oil and gas, and transportation and delivery should be on high alert for both programmed and targeted inspections when high temperatures or heat-index conditions are present. 

To help prepare employers, on April 10, 2026, OSHA updated its National Emphasis Program on Outdoor and Indoor Heat-Related Hazards, to include, among other things, a list of questions employers can expect to answer during a programmed or unprogrammed heat inspection and guidance OSHA Compliance Officers will use to evaluate whether to issue a General Duty Clause violation for heat-related hazards. 

States fill the gap

In the absence of a federal heat-specific standard, several State Plan states (not just California) have moved ahead with their own requirements. Some state rules focus primarily on outdoor work, while others address indoor heat exposure as well. The broader trend is clear: states are increasingly adopting more detailed heat illness prevention obligations for employers, and employers with multistate operations should not assume that a heat stress program designed for one jurisdiction will satisfy the requirements of another.

Though state standards and regulations differ in scope and requirements, they often trigger employer obligations based on temperature, require employers to have and implement a written heat stress policy or procedure, ensure employees have drinking water, shade or other cooling measures, cool-down rest periods, training, acclimatization, and emergency response procedures. Some states’ standards or regulations apply to just outdoor workplaces (Washington) and other states’ standards apply to both indoor and outdoor workplaces (California, Nevada, Maryland). To date, California, Colorado, Washington, Oregon, Minnesota, Nevada, and Maryland all have heat-related standards or regulations that apply to at least some industries and worksites.

Pennsylvania may soon join the list of states with detailed heat stress rules. State representatives have introduced the proposed Pennsylvania Workplace Heat Protection Standards Act, which would direct the Pennsylvania Department of Labor and Industry to adopt comprehensive regulations addressing heat-related hazards.

Practical tips for employers

Regardless of whether an employer has operations in one of the states that has a heat-related standard or regulation, the most effective heat stress strategy is proactive, site-specific, and documented. 

• Develop a written plan that is tailored to your workplace that identifies responsible personnel, applicable trigger thresholds, preventive controls, acclimatization procedures, training requirements, emergency response steps, and anti-retaliation protections.
• Identify where heat exposure may occur across the organization. Outdoor risks may be obvious, but indoor risks can be just as significant in warehouses, production areas, commercial kitchens, boiler rooms, maintenance spaces, and areas with poor airflow or heat-generating equipment. Employers should assess not only ambient temperature but also humidity, radiant heat, air movement, workload, required clothing or personal protective equipment, and employees’ physical exertion.
• Monitor weather forecasts and heat-index conditions during warm months and designate responsibility for deciding when enhanced precautions are required or should be implemented. For indoor environments, employers should consider using thermometers, heat-index tools, or other appropriate measurement methods in areas where heat may accumulate.
• Implement engineering and/or administrative controls appropriate for the workplace. Effective controls may include ventilation, fans, evaporative coolers, air conditioning, reflective barriers, insulation of hot surfaces, shade structures, cooled break areas, mechanized equipment, earlier start times, reduced work intensity, job rotation, and more frequent rest periods.
• Ensure that cool drinking water is readily accessible and that employees are encouraged, not merely permitted, to drink it.
• Develop an acclimatization plan for new employees to allow those assigned to hotter or more strenuous work to ease into their job tasks.
• Train employees and supervisors on signs and symptoms of heat stress, what to do in an emergency, and applicable heat stress policies and procedures.