Summer’s heat is here and brings the leading cause of death among all hazardous weather conditions in the United States, according to OSHA. Data from the Bureau of Labor Statistics show nearly 480 workers died from exposure to environmental heat from 2011-2022, an average of 40 fatalities per year.

Both outdoor and indoor workers can be affected by extreme heat, which is why OSHA is still focused on protecting America’s workforce from heat-related hazards. Stakeholder feedback from the proposed Heat injury and Illness Prevention rule public hearing on June 16 gives the agency essential information to analyze and review. Once reviewed, OSHA will determine the rule’s final destiny – finalization and publishing to the Federal Register or being put on the back burner until further research can be done.

The public comment period on OSHA’s proposed Heat rule closed on January 14, 2025, with a public hearing held June 16, 2025. The agency has not provided a date for a final rule. Typically, there is a 24- to 60-month review period following the public hearing. Effective dates are often 60 days after publication of the final rule, with full compliance expected at 150 days.

OSHA’s proposed heat rule would apply to all employers conducting outdoor and indoor work in all general industry, construction, maritime, and agricultural sectors under the agency’s jurisdiction with a few exceptions. However, it excludes short-duration heat exposures, emergency response activities, indoor sites kept below 80°F, telework, and indoor sedentary work activities.

In addition to temperatures, heat generation from industrial processes and radiant heat such as ovens and furnaces have also been considered throughout the rulemaking process.

“Indoor” is defined in the proposed rule as “an area under a ceiling or overhead covering that restricts airflow and has along its entire perimeter walls, doors, windows, dividers, or other physical barriers that restrict airflow, whether open or closed.” Examples include:

• A garage, even if the door is open;
• The interior of a warehouse, even if multiple doors are open on loading docks; and
• A shed with four walls and a ceiling, even if the windows are open.

Construction activity is considered “indoors” when performed inside a structure after the outside walls and the roof are built.

Key elements in OSHA’s proposed rule will require impacted employers to:

• Develop a Heat Illness Prevention Plan (HIPP) that addresses risk assessments, monitoring, exposure controls, emergency response to heat stress, training, and documentation;
• Evaluate the HIPP annually;
• Identify and respond to heat hazards for outdoor and indoor environments affected by excessive heat (e.g., at 80 degrees, employers must provide water and rest breaks and at 90 degrees, employers must monitor signs of heat illness and provide mandatory 15-minute breaks every two hours);
• Establish heat metric(s) and monitoring systems for protecting employees from excessive heat;
• Designate a heat safety coordinator;
• Institute “water – rest – shade” procedures to ensure workers can cool down when necessary;
• Develop heat illness and heat-related emergency response plans;
• Implement engineering controls such as ventilation and air conditioning and administrative controls including acclimatization and water – rest – shade;
• Provide initial and refresher training for supervisors, heat safety coordinators, and employees to ensure understanding of heat hazards, personal risk factors, recognition of early symptoms of heat stress, and activation of emergency services when necessary; and
• Maintain written or electronic records of indoor temperature monitoring results for six months.

OSHA’s proposed Heat rule contains numerous requirements for employers, but it remains to be seen which provisions are retained in a final version. Following the June 16 public hearing, the agency will review comments it received and determine next steps.