The World Health Organization and the World Meteorological Organization have issued their first comprehensive guidance in more than five decades on protecting workers from extreme heat, warning that climate-driven temperature rises now pose a major health and economic risk. The joint United Nations report says 2.4 billion people—about 70 % of the global workforce—are regularly exposed to dangerous heat, with 2024 registering as the hottest year ever recorded. The study links excessive heat to heatstroke, dehydration, kidney dysfunction and neurological disorders, and estimates that worker productivity drops by 2–3 percent for every degree Celsius above 20 °C. The International Labour Organization calculates that heat stress already contributes to more than 22.85 million occupational injuries each year. “Protection of workers from extreme heat is not just a health imperative but an economic necessity,” WMO Deputy Secretary-General Ko Barrett said, while WHO’s Rüdiger Krech noted that no one should “risk kidney failure or collapse just to earn a living.” The agencies urge governments and employers to create occupational heat-action plans tailored to local climates and industries, consider legal maximum working temperatures, and expand training so health professionals can correctly diagnose heat stress. Outdoor labourers in agriculture, construction and fisheries, along with older and low-income workers, are singled out as especially vulnerable. The report calls for collaboration among employers, unions and public-health experts to ensure mitigation measures are practical and scalable in a warming world.