Following the successful 2024 launch of its original heat stress app, AIHA (American Industrial Hygiene Association) — led by Lawrence D. Sloan, National Commission on Climate and Workforce Health Commissioner and current AIHA CEO — has released Heat Stress App 2.0.

Now tailored to indoor workers working in non-air-conditioned environments, the updated version also helps users assess heat risks from localized heat sources like ovens and furnaces. The app is free to download on iOS and Android platforms and is available in four languages: English, Spanish, French, and Portuguese. To download the app, click here.

What’s New in Heat Stress App 2.0

Previously, AIHA’s original heat stress app helped outdoor workers and their employers assess job-related heat health risks. The app update now allows users to select whether they work indoors or outdoors, prompting them to select specific criteria about their workplace. 

The indoor workers’ version measures key heat risk factors in enclosed environments, such as: 

• Indoor temperature and relative humidity
• Non-solar heat irradiance (from nearby hot equipment or materials)
• Wind speed
• Workload intensity
• Clothing

Why Indoor Workers Are at Risk

According to the Centers for Disease Control and Prevention (CDC), extreme heat is the leading weather-related killer in the United States. Indoor heat stress can be just as dangerous as outdoor heat stress.

“While heat stress risks for outdoor workers are more obvious due to intense sunlight and high outdoor temperatures and humidity levels, heat stress that workers face in indoor environments may be vastly underestimated — especially when there is a localized heat source, such as a hot oven or furnace,” said Lawrence D. Sloan.

Limited climate control or ventilation in foundries, commercial kitchens, and warehouses can lead to dangerous heat buildup from ambient temperatures and indirect solar radiant heat. Indoor heat exposure can result in occupational illnesses and increase workers’ risk of injuries.

Employees are at greatest risk when they are not acclimatized to their work environment, perform strenuous activity, or wear heavy or non-breathable clothing. Learn how to recognize heat stress symptoms and lower your risk at AIHA’s employee resource page.

Employers can conduct risk assessments, provide hydration and cooling areas, adjust work hours, and offer symptom-recognition training to prevent worker injury risk and increase productivity. For employers looking to implement effective prevention measures, visit AIHA’s employer resource page.

How the App Calculates Risk

The app uses the Wet Bulb Globe Temperature (WBGT) index, widely recognized as the gold standard in evaluating environmental heat stress, to translate indoor conditions into a heat stress risk score. Based on an individual's risk level, the app also delivers heat alerts and health recommendations (e.g., rest breaks and water consumption). 

Additional resources include fast reads on recommended heat stress prevention measures, warning signs of heat-related illness, and recommendations for heat acclimatization.

Empowering Business Leaders To Take Action

The National Commission on Climate and Workforce Health is a group of business, health, and climate leaders who share a mission to protect workers from the health risks posed by extreme weather.

Want free tools to help your company adapt to today’s climate conditions and invest in human and business resilience? Sign up for our monthly newsletter to stay up to date on the Commission's latest resources and recommendations.

The Commission was created by the Health Action Alliance in partnership with Mercer and with strategic input from the CDC Foundation. Additional support for the initiative is being provided by Elevance Health and The Hartford. Learn more at ClimateHealthCommission.org.

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