Heat Stress

The National Institute for Occupational Safety and Health (NIOSH) has outlined criteria for a recommended standard addressing occupational heat stress. This document offers guidance to employers on preventing heat-related illnesses.

Various U.S. states operate their own OSHA-approved State Plans, some of which have adopted standards covering hazards not addressed by federal OSHA standards. Notable states with heat exposure standards include:

• California: The Heat Illness Prevention Standard mandates training, water, shade, and planning, triggered at 80°F.
• Colorado: Reflected in the Agricultural Labor Conditions Rules for heat.
• Minnesota: Applicable to indoor places of employment.
• Oregon: Encompasses both General Occupational Safety and Health (including construction and forest activities) and Agriculture.
• Washington: Covered under the Outdoor Heat Exposure Rule.

• Personal Protective Equipment (PPE) Standard (29 CFR 1910.132(d)): Requires employers in general industry to conduct hazard assessments for appropriate PPE use.
• Recordkeeping Regulation (29 CFR 1904): Mandates the recording of work-related injuries and illnesses, with specific reporting requirements for fatalities and inpatient hospitalizations.
• Sanitation Standards (29 CFR 1910.141, 29 CFR 1915.88, 29 CFR 1917.127, 29 CFR 1918.95, 29 CFR 1926.51, 29 CFR 1928.110): Ensures the provision of potable water.
• Medical Services and First Aid Standards: Require adequate training for on-site personnel (29 CFR 1910.151, 29 CFR 1915.87, 29 CFR 1917.26, 29 CFR 1918.97, 29 CFR 1926.50).
• Safety Training and Education Standard for Construction (29 CFR 1926.21): Specifies safety training requirements.

Several Letters of Interpretation provide guidance on specific issues, including the use of personal protective equipment, recordkeeping for heat-related illnesses, and acceptable methods to reduce heat stress in the workplace.

• The use of hard hats while working on roofs in hot weather. (August 1, 2014). Addresses concerns related to the use of hard hats and roofers’ risk of heat-related illnesses from exposure to excessive heat.
• Whether the use of personal protective equipment is mandatory when working under heat stress conditions. (May 18, 2010). OSHA guidance for choosing appropriate PPE to protect workers from electrical hazards when heat stress is a factor.
• Clarification of preexisting injury/illness and recordkeeping. (October 6, 2009). Clarifies recordkeeping requirements for heat-related illnesses.
• Wearing short-sleeved shirts while performing a thermal spray operation with exposure to hexavalent chromium fumes. (January 25, 2007).
• Requirements for “nature breaks” and weather-related “comfort breaks” for U.S. Postal Service employee. (May 12, 2006)
• Acceptable methods to reduce heat stress hazards in the workplace. (October 17, 2001). Identifies feasible and acceptable methods that can be used to reduce heat stress in workplaces.
• Fire retardant PPE requirements and PPE hazard assessment. (March 27, 1998). Identifies heat and cold stress as factors considered under PPE hazard assessment.
• Interpretation of OSHA requirements for personal protective equipment to be used during marine oil spill emergency response operations. (September 11, 1995). 29 CFR 1910.132(d) mandates that the employer perform a hazard assessment of the workplace to determine if the use of PPE is necessary; select and mandate worker use of the necessary PPE; communicate selection of PPE decisions to workers; and select PPE that properly fits the employees.
• Landscaping employees working in extreme temperatures. (July 14, 1992).