Heat Safety Tool App


NIOSH and OSHA recently released the redesigned, co-branded OSHA-NIOSH Heat Safety Tool App. This version replaces the app previously created by OSHA in 2011. This app provides recommendations to prevent heat-related illnesses and reduce heat stress in outdoor workers based on local weather conditions used to calculate the heat index.

The app calculates the heat index at outdoor worksites using the smartphone’s geolocation capabilities to pull current weather conditions from the National Oceanic and Atmospheric Administration (NOAA) satellites. Based on the calculated heat index, users are provided specific sets of recommendations for protections against the heat.

Workers and managers can use these recommendations to adjust their work environment. The app recommendations were updated to reflect information found in the NIOSH Criteria for a Recommended Standard: Occupational Exposure to Heat and Hot Environments (published in 2016).

Along with updated recommendations, the co-branded app has new features and improved usability. With a basic understanding of the heat index, the app is a useful tool for working safely outdoors.

The heat index is a measure of how hot it feels when relative humidity is taken into account along with the actual air temperature. It is important to note that since heat index values were devised for shady, light wind conditions, exposure to full sunshine can increase heat index values by up to 15°F.

The App allows workers and supervisors to calculate the heat index for their worksite, and, based on the heat index, displays a risk level to outdoor workers. Then, with a simple “click,” you can get reminders about the protective measures that should be taken at that risk level to protect workers from heat-related illness-reminders about drinking enough fluids, scheduling rest breaks, planning for and knowing what to do in an emergency, adjusting work operations, gradually building up the workload for new workers, training on heat illness signs and symptoms, and monitoring each other for signs and symptoms of heat-related illness.

Working in full sunlight can increase heat index values by 15 degrees Fahrenheit. Keep this in mind and plan additional precautions for working in these conditions.

The OSHA Heat Tool is available in Spanish for Android and iPhone devices. To access the Spanish version on the iPhone, set the phone language setting to Spanish before downloading the app.

Stay informed and safe in the heat, check your risk level.

For more information about safety while working in the heat, see OSHA’s heat illness webpage, including new online guidance about using the heat index to protect workers.

The National Weather Service uses the heat index values to issue heat alerts, such as:

  • Excessive Heat Outlook – Extended excessive heat (heat index of 105°F-110°F [41°C-43°C]) over the next 3 to 7 days.
  • Excessive Heat Watch – Excessive heat may occur within the next 24 to 72 hours.
  • Excessive Heat Warning – The heat index will be life threatening in the next 24 hours. Excessive heat is imminent or has a high probability of occurring.
  • Excessive Heat Advisory – The heat index may be uncomfortable but not life threatening if precautions are taken.