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| 4 minutes read

OSHA Proposes Heat Stress Standard

On July 2, 2024, OSHA released its long-anticipated heat stress standard. It is a broad standard that, if finalized, will apply to employers in both construction and general industry. It is also a somewhat complicated standard. For example, whether or not particular employees are covered depends upon whether employees can reasonably be expected to work in temperatures exceeding what OSHA calls the “initial heat trigger.” The initial heat trigger is either a National Weather Service heat index (what the body’s temperature feels like when considering relative humidity and air temperature) of 80º F or a “wet bulb globe temperature” (a heat metric that takes into account air temperature, humidity, radiant heat and air movement) equal to recommended alert limits set by the National Institute for Occupational Safety and Health (NIOSH). If employees cannot reasonably be expected to work in conditions reaching the initial heat trigger, or if they can only be expected to do so for durations of 15 or less minutes per hour, the standard does not apply to them. 

Other exclusions from the standard include emergency services, indoor work where air conditioning keeps the temperature below 80º F, telework, and indoor sedentary work such as sitting, occasional standing and walking, and lifting objects less than 10 pounds.  If all of an employer’s employees fall within one or more of these exclusions, it does not have to comply with the standard.  If some employees fall inside an exception and some do not, the employer must comply with respect to those work activities that are covered.

The main requirement of the standard is that employers develop a site-specific Heat Illness and Injury Prevention Plan (HIIPP).  A HIIPP must include the following:

  • A comprehensive list of the types of work activities it covers;
  • All policies and procedures necessary to comply with the standard;
  • An identification of the heat metric, i.e., heat index or wet bulb globe temperature, the employer will utilize;
  • A heat monitoring plan; and
  • A heat emergency response plan.

Employers with 10 or more employees must have a HIIPP that is in writing. All covered employers must designate one or more “heat safety coordinators” to implement the HIIPP and must seek the input of non-managerial employees in the development and implementation of the HIIPP. Additionally, employers must evaluate their HIIPP annually or when a heat-related OSHA recordable event takes place. The HIIPP must be made available to all employees and in a language that they can understand.

Outdoor work employers are required to monitor heat conditions by tracking National Weather Service forecasts, by actually measuring the heat conditions at the worksite, or by assuming that work areas are covered. For indoor work, employers are required to identify each area where employees reasonably can be expected to be working at or above the initial heat trigger. 

Once the initial heat trigger is reached, employers must implement the following controls:

  • Provide access to potable water that is reasonably cool and of sufficient quantity to provide access to one quart of drinking water per employee per hour;
  • Provide break areas;
    • For outdoor locations this means one or more areas that can accommodate the number of employees on break and that has either artificial shade (not from equipment), natural shade, or air conditioning in an enclosed space
    • For indoor work areas this means areas with air conditioning or increased air movement and, if appropriate, dehumidification
  • For indoor areas identified as reaching the initial heat trigger provide increased air movement (such as fans or comparable ventilation and, if appropriate, dehumidification), air conditioning, or means of reducing any radiant heat sources;
  • Provide acclimatization to new and returning employees;
  • Allow and encourage paid rest breaks;
  • Provide two-way communication with employees; and
  • Ensure that if cooling PPE is being used that it is properly maintained.

The new standard also contains requirements for “high heat trigger” conditions. High heat trigger conditions exist when the heat index is 90º F or when the wet bulb glow temperature is equal to NIOSH recommended exposure (as opposed to alert) limits. When these conditions exist employers must:

  • Provide a paid rest break of at least 15 minutes every two hours;
  • Provide observation for signs of heat stress; and
  • Alert employees to the conditions and measures to be taken, such as water intake, rest breaks, and how to seek help in am emergency situation.

As for the HIIPP’s heat emergency response plan, employers must include the following:

  • A list of emergency phone numbers;
  • A description of how employees can contact supervision and emergency medical services;
  • The individuals designated to ensure that heat emergency procedures are invoked where appropriate;
  • A description of how employees can be transferred to a place where they can be reached by medical providers;
  • Clear directions to the worksite that can be given to emergency dispatchers; and
  • Procedures for responding to an employee experiencing heat stress.

The new standard also provides detailed procedures employers must follow when employees experience signs and symptoms of heat-related illness, including monitoring, the provision of first aid, reducing body temperature, and contacting emergency services. It also contains training procedures that must be implemented for both employees and supervisors.

The standard has not yet been published in the federal register. Once it is, it will become effective within 60 days, and employers will have 150 days to come into compliance. In the meantime, OSHA will continue to enforce heat stress issues through enforcement of the General Duty Clause.

This action by OSHA is the result of an extended rulemaking process based on the increased number of heat-related illnesses experienced by workers. Employers are encouraged to review the standard carefully and begin implementing its requirements.  


labor and employment and employee benefits, workplace safety