The OSHA NIOSH Heat Safety Tool represents a specialized government-developed application designed to address occupational heat exposure risks. Developed by the Centers for Disease Control and Prevention, this Android application serves as a digital companion for outdoor workers and safety managers who require accurate environmental monitoring to comply with workplace safety regulations. The app occupies a unique position in the market as one of the few tools backed directly by federal safety agencies. The application's core functionality centers on real-time heat index calculation using location data, providing both current conditions and hourly forecasts. The interface displays color-coded risk levels ranging from caution to extreme danger, accompanied by specific OSHA and NIOSH recommendations for each risk category. Additional features include hydration reminders, rest break guidance, and educational resources about heat illness symptoms and prevention strategies. The tool automatically updates based on GPS coordinates, eliminating manual data entry requirements. User experience analysis reveals a functional but utilitarian interface prioritizing information clarity over aesthetic appeal. The main screen presents the current heat index prominently with corresponding safety recommendations immediately accessible. Real-world usage patterns indicate the app serves primarily as a pre-shift planning tool and periodic safety check during work hours. Field testing shows reliable performance when location services function properly, though some users report occasional connectivity issues affecting data accuracy. User feedback trends demonstrate polarized experiences, with many praising accuracy while others report technical issues. Multiple five-star reviews from 2023-2024 highlight the app's precision compared to manual calculations, with user 'No Thankyou' noting on June 25, 2023: 'The app seems to be very accurate compared to how I normally calculate Heat Index by hand.' However, technical problems persist, as evidenced by 'Chrysanthi Gavagan's' June 21, 2024 review detailing location data failures despite permission checks and reinstallations. Feature requests include timestamp documentation for compliance purposes, as mentioned by user 'Rafael' on July 21, 2024. The application's primary strength lies in its authoritative safety recommendations directly from regulatory agencies, making it valuable for compliance documentation. However, the 2.9 rating reflects persistent technical reliability issues that undermine its utility. The tool serves best as part of a comprehensive heat safety program rather than a standalone solution, particularly for construction, agriculture, and landscaping professionals requiring OSHA-compliant heat illness prevention measures.