This report by Urban Institute researchers offers the first nationally representative estimates of how outdoor and indoor workers are affected by extreme heat, highlighting that low-wage workers, defined as adults earning less than $15 an hour, face greater risks than higher-wage earners. This study reveals that more than 1 in 7 outdoor workers experienced heat exhaustion or heat-related symptoms at their jobs in 2023. Other key findings include that heat exhaustion is a significant issue, disproportionately affecting vulnerable groups such as Hispanic/Latinx men, low-wage earners, and individuals in fair health. Among indoor workers in non-climate-controlled environments, nearly 9 percent reported heat exhaustion. The highest rates of heat-related symptoms were reported in agriculture, mining, and construction, with nearly 19 percent of workers affected. The findings come as the federal government considers the first-ever national worker protections against extreme heat, emphasizing the need to identify vulnerable groups and inform policy decisions. The report underscores the need for comprehensive federal workplace heat safety standards that cover both outdoor and indoor workers across all industries, along with collective bargaining agreements and voluntary actions by businesses to mitigate the impacts of extreme heat on workers.