The Heat Is On
OSHA’S National Emphasis Campaign on Heat Illness Prevention Could Preface a National Standard
by: By Rachel Brown

Section: Features-Summer 2023


Direct Sun Exposure Indoor Radiant Heat Sources Limited Air Movement Lack of Recent Exposure Pregnancy Not enough Fluids Medications Physical Conditioning & Health Problems PPE & Clothing Physical Exertion Advanced Age

Many industries are experiencing the challenges of keeping workers safe from heat illness as temperatures soar are adapting to new standards as a result. The construction industry, which includes spray polyurethane foam application, is no exception.

Heat is the leading cause of weather-related fatalities, according to The Centers for Disease Control and Prevention (CDC). Workers suffer over 3,500 injuries and illnesses related to heat each year. While extreme heat has always posed a danger to workers – indoors and outdoors – increasing temperatures have posed even more significant risks, with 18 of the last 19 years ranking the hottest on record.

Excessive heat claimed an average of 143 lives per year in the U.S. from 1991 through 2020, according to the National Oceanic and Atmospheric Administration (NOAA). That’s higher than the average annual death tolls from flooding (85), tornadoes (69), hurricanes (46) and lightning (39) in that 30-year period.

For the first time, the U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA) has launched a National Emphasis Program to protect millions of workers from heat illness and injuries. Through the program, OSHA will conduct heat-related workplace inspections before workers suffer completely preventable injuries, illnesses or, even worse, fatalities.


OSHA currently relies on the general duty clause (OSHA Act Section 5(a))(1)) to protect workers from heat illness, but recently issued an Advanced Notice of Proposed Rulemaking in October 2021 to call attention to a possible federal standard down the pipeline. While several states have issued heat protection rules, a national standard is lacking.

"Every heat fatality I’ve ever investigated has been 100% preventable," said Victor Ramon, Compliance Assistance Specialist, OSHA. "There have been way too many heat-related incidents."

OSHA is implementing its enforcement initiative on heat-related hazards by developing a National Emphasis Program (NEP) on heat inspections and launching a rulemaking process to develop a workplace heat standard. This initiative, which will remain in effect for three years, would be applied on days when the heat index rises above 80 degrees Fahrenheit.

As part of the program, OSHA will proactively initiate inspections in over 70 high-risk industries in indoor and outdoor work settings when the National Weather Service has issued a heat warning or advisory for a local area. On days when the heat index is 80 degrees F or higher, OSHA inspectors and compliance assistance specialists will engage in proactive outreach and technical assistance to help stakeholders keep workers safe on the job. Inspectors will look for and address heat hazards during inspections, regardless of whether the industry is targeted in the NEP.

"The trigger point is when the heat index exceeds 80 degrees Fahrenheit," Ramon said. Ramon suggested using the OSHA-NIOSH Heat Index app, a downloadable app via most devices and smartphones that can serve as a planning and monitoring tool while employees are working.

Further, employers should create a heat illness plan to protect workers from heat illness by monitoring all workers for heat illness; providing plenty of water and cool areas for breaks; allowing workers to gradually increase workloads or take more frequent breaks as they acclimatize or build tolerance to heat; establishing a plan for heat emergencies, i.e., dangerous, extreme temperatures or employee heat stroke; and training supervisors on recognizing heat hazards and heat illness symptoms.



There are relatively simple precautions workers can take to prevent heat illness. It’s important employers help educate and enforce these preventive measures to avoid potential illness or even worse, heat-related death.

"Three out of four fatalities from heat illness happen during the first week of work," said Ramon. The first step in prevention is acclimatization for new and returning workers who need to build tolerance to heat by taking frequent breaks. He suggested following the 20% rule: On the first day, only work 20% of that shift at full intensity in the heat. After that, increase the time working at full intensity by 20% each day. "If a fatality occurs after acclimatization, liability (of the employer) goes down," Ramon said.

Personal and protective clothing and equipment is something else to consider in heat illness prevention. For indoor work, loosely worn reflective clothing is recommended to deflect radiant heat, such as vests, aprons or jackets, Ramon said. Cooling vests and water-cooled/dampened garments may be effective under high temperature and low humidity conditions.

In environments where respirator usage is necessary, Ramon suggested consulting with an industrial hygienist to determine the appropriate clothing to prevent heat stress while still protecting workers.

Tools such as dermal patches for core temperature monitoring and heart rate monitors to identify when workers need a break can further aid in monitoring the work site. Both sustained (180 minus age) and recovery (120 bpm after a peak work effort) heart rates are recommended guidelines for limiting heat strain.

For those looking for more insight, OSHA offers a free on-site consultation program to small- and medium-sized businesses where consultants from state agencies or universities work with employers to identify workplace hazards, provide advice for compliance with OSHA standards, and assist in establishing and improving safety and health programs.

There are resources on OSHA’s website to review and to help employers formulate a plan:


While monitoring the team as a whole is important, there are individual risk factors that come into play when considering heat illness. Employers aren’t always aware of these individual circumstances – and sometimes, the worker is not either.

"Educate employees on certain medications and how they can affect heat," Ramon said. Three out of four fatalities happen during the first week of work."

Certain health conditions, such as pregnancy, medications and age, can all play a factor in elevated risk to heat exposure. Additionally, using illegal drugs and alcohol in hot work environments are particularly dangerous. Workers should consult a doctor or pharmacist about wither they are at increased risk for heat-related illness due to health conditions or medications.