Summer may now be over, but the debate over how OSHA should regulate worker exposure to heat – indoors and out – may be getting hotter. Over the summer, both the National Institute for Occupational Safety and Health (NIOSH) and a coalition of private advocacy groups and individuals supported OSHA developing a heat stress standard. While OSHA has offered guidance on protecting workers from overheating and cited companies under the catch-all General Duty Clause, it does not currently have particular heat exposure limits or mandates.

The renewed discussion of a national OSHA standard began when NIOSH released a report on July 6, 2018 recommending that companies comply with the agency’s unofficial exposure limits. The paper echoed NIOSH’s long-standing recommendations that OSHA adopt an occupational heat stress rule. Those recommendations, first developed in 1972 and revised in 1986 and 2016, are in a NIOSH document called Criteria for a Recommended Standard: Occupational Exposure to Heat and Hot Environments.

NIOSH says current OSHA guidance “might not be sufficiently protective”

In its most recent report, NIOSH suggested tightening its recommendations further. The research agency said that by looking at OSHA records of 25 individual heat stress cases, it could “validate” appropriate exposure limits. Moreover, it concluded that OSHA’s “current occupational Heat Index guidance might not be sufficiently protective,” and it suggests a lower temperature threshold than before for taking protective measures.

NIOSH generally has recommended that OSHA impose permissible exposure limits for heat stress due to heat in the environment based on the “Wet Bulb Glove Temperature” (WBGT), which includes factors such as humidity, sunlight, and wind. It would also limit exposures based on metabolic heat (based on workload).

While NIOSH says that WBGT is the “gold standard,” outdoor work sites often do not have this measurement available and rely on weather reports for heat index information. Until now, NIOSH and OSHA have suggested that 91°F was the level for taking additional precautions.

However, NIOSH now says that the trigger for heightened preventive measures should be lower because “at a heat index of 85°F (29.4°C), workers wearing normal clothing are at risk for heat related illness.” As a result, says NIOSH, OSHA’s current guidance “might not be sufficiently protective,” and employers should implement additional protective measures to prevent heat-related illness and to screen for hazardous workplace environmental heat at 85°F.

Do you have a heat-related illness prevention program?

NIOSH has further recommended that employers adopt a comprehensive heat-related illness prevention program, including at least the following general components:

• Measure heat stress throughout the day using WBGT;
• Take actions to prevent heat exposure in excess of exposure limits;
• Use a heat index of 85° when WBGT is unavailable to screen for hazardous heat exposure;
• Use an acclimatization schedule for newly hired or long-term unacclimatized workers;
• Use engineering and administrative controls to reduce heat stress;
• Provide medical surveillance; and
• Provide fluids and shade areas for rest breaks.

OSHA also has extensive resources on its web site with guidance for dealing with heat exposure at different levels, including developing programs and training employees.

Private groups also call for a national heat stress standard

In the wake of the NIOSH report, Public Citizen, a consumer health advocacy group, submitted a letter on behalf of over 130 of organizations and 90 individuals, renewing a call for a national heat stress standard. In the letter, they petitioned OSHA to initiate the rulemaking process to formulate such a standard. They note that several states already have state heat stress regulations.

In 2012, Assistant Secretary David Michaels denied a similar petition saying, among other reasons, that it was unnecessary since OSHA has authority under the General Duty Clause to cite employers for hazardous heat exposure violations. A case pending before the OSHRC, Secretary of Labor, Department of Labor v. A.H. Sturgill Roofing, Inc., may address whether OSHA can continue to use the General Duty Clause in this way. Interestingly, this time, Dr. Michaels, who is no longer in office, actually signed onto the petition with Public Citizen, asking OSHA to issue the standard that he declined to issue in the past.

If your employees are exposed to potential hot conditions or heat stress, it is wise to include heat illness prevention measures in your safety plans and policies.