Extreme heat poses acute and chronic risks to workers across South Asia, yet personal exposure data from occupational settings remain scarce. Informal workers, who dominate textile and sanitation sectors, are disproportionately vulnerable: despite labor protections, they operate outside labor laws, lacking written contracts, social security, and healthcare benefits, while facing severe occupational, social, and economic hazards. Tamil Nadu is a major hub of India’s textile sector value chain. The state has recently surpassed Gujarat and Karnataka to emerge as the country’s leading textile exporter. While Tirupur and Erode have long dominated in textile manufacturing, Dindigul and Virudhunagar are emerging as significant centers, driven by Micro, Small and Medium Enterprises (MSME) concentration and Virudhunagar’s inclusion in the PM MITRA park programme. These districts are also experiencing escalating heat stress driven by climate change. Textile workers face sustained physical exertion in poorly ventilated factory floors, with heat risks compounded by hot commutes and heat-burdened homes. Sanitation workers face a similarly compounding vulnerability. By 2015, Tamil Nadu had outsourced sanitation work to contractual workers, the majority of whom were women. Drawn from particularly marginalized communities, these workers are exposed to severe occupational hazards such as harmful gases, sharp object injuries, and musculoskeletal disorders, while lacking adequate Personal Protective Equipment (PPE) and labor protections. Rising temperatures render this dangerous work increasingly life-threatening. Across both sectors, standard heat-health surveillance relies on ambient outdoor temperature, which fails to capture the layered exposures workers experience across workplace, transit, and domestic environments. Without personal exposure data collected in partnership with workers, the true heat burden in these populations cannot be fully characterized and evidence-based occupational heat standards will be challenging to develop.