An OSHA Heat Safety Tool App on their mobile phones allows workers with heat sensitivity to appropriately plan for and/or engage in outdoor work activities based on how hot it feels throughout the day. This app will visually indicate the current heat index and associated risk level specific to that worksite then recommend protective measures that should be taken in light of those heat index-based risk levels. It also provides first-aid information if heat-related illness is experienced. The app is available in English and Spanish for Android and iPhone devices.