OSHA’s proposed heat rule: Compliance and enforcement considerations ahead of finalization

The Occupational Safety and Health Administration (OSHA) has proposed a rule aimed at regulating heat-related hazards in the workplace. 

If finalized, the rule, entitled “Heat Injury and Illness Prevention in Outdoor and Indoor Work Settings,” would be the first federal labor rule to specifically address heat-related risks. It would impose nationwide, affirmative obligations on employers to evaluate and control heat exposure in both outdoor and indoor environments. As a result, the rule’s finalization would represent a new development for employers subject to OSHA’s jurisdiction, adding to the existing set of legal and compliance obligations that companies face in connection with environmental risks.

This alert discusses the proposed rulemaking, existing enforcement mechanisms, and compliance considerations for employers ahead of any final rule.

Background

OSHA first proposed the rule in August 2024 and, in January 2025, extended its National Emphasis Program (NEP) on outdoor and indoor heat-related hazards from April 8, 2025 to April 8, 2026. The extension provides interim enforcement guidance for employers while the proposal remains pending. The proposed rule remains listed on the Office of Information and Regulatory Affairs’ most recent Unified Agenda. 

Overview of proposed rule and enforcement 

The proposed rule states that extreme heat is the leading cause of death among weather-related fatalities. It would require employers to create a heat injury and illness prevention plan to evaluate and control heat hazards in the workplace. The rule would also establish requirements for:

• Identifying heat hazards
  
  
• Implementing engineering and work practice control measures
  
  
• Developing and implementing a heat illness and emergency response plan
  
  
• Providing training to employees and supervisors
  
  
• Retaining certain records

The proposed rule has broad applicability and would cover all employers under OSHA’s jurisdiction, subject to limited exceptions, such as short-term employee exposure to high heat levels or work activities for which there is no reasonable expectation of heat hazards.

In the proposed rule, OSHA preliminarily determines that heat index thresholds of 80°F and 90°F are protective of workers and generally consistent with existing state-level heat illness prevention standards. The rule would require employers to implement defined control measures when the initial heat trigger of 80°F is reached, with additional controls required at the high-heat trigger of 90°F.

Specifically, upon reaching the initial heat trigger, employers would be required to implement certain control measures, including:

• Acclimatization protocols for employees during their first week of work
  
  
• Access to suitably cool drinking water in readily accessible locations and in sufficient quantities (i.e., one quart per employee per hour)
  
  
• Indoor work area controls (e.g., air conditioning or fans)
  
  
• Paid rest breaks in areas with cooling measures that can be taken as needed

Further, upon reaching the high-heat trigger, employers would be required to implement the control measures applicable at the initial heat trigger, as well as additional measures including:

• Hazard alerts reminding employees to drink water and take breaks
  
  
• Systems for observing employees for signs and symptoms of heat-related illness
  
  
• Mandatory paid 15-minute rest breaks every two hours in break areas with cooling measures.

At present, in the absence of a heat-specific standard, OSHA generally addresses hazardous heat conditions in the workplace through enforcement under the Occupational Safety and Health Act’s General Duty Clause (Section 5(a)(1)). Under this provision, employers are required to furnish employees with employment and a place of employment “free from recognized hazards that are causing or are likely to cause death or serious physical harm.” To establish a violation of the General Duty Clause, OSHA must demonstrate that:

• The employer failed to keep the workplace free of a hazard to which its employees were exposed
  
  
• The hazard was recognized

• The hazard was causing or likely to cause death or serious physical harm
  
  
• A feasible means existed to eliminate or materially reduce the hazard

While the timing and scope of final rulemaking remain uncertain, OSHA’s existing enforcement authority allows the agency to continue citing heat related hazards regardless of whether the proposed rule is finalized. In doing so, OSHA has relied on the General Duty Clause, as well as enforcement emphasis programs, hazard alerts, and other guidance – including its NEP on outdoor and indoor heat-related hazards. A heat-specific injury and illness prevention standard, such as that proposed by OSHA, would more clearly articulate enforceable employer obligations and provide a defined regulatory framework for addressing workplace heat hazards.  

Learn more

If you have questions regarding this alert, please contact one of the authors or your regular DLA Piper contact.

DLA Piper’s Environment, Health and Safety and Environmental and Catastrophic Events teams help clients anticipate, manage, and respond to emerging workplace risks driven by extreme heat, environmental events, and evolving enforcement priorities. Our multi-disciplinary teams advise on regulatory compliance, inspections and enforcement actions, internal investigations, and follow on litigation arising from environmental hazards.