Characterizing Heat Health Hazards and Receptivity of Cooling Interventions Among Indoor Lumber Mill Workers in Southern Thailand

OBJECTIVE: To evaluate the effectiveness and feasibility of two workplace cooling strategies and identify priorities for future mixed-methods research and practical solutions. METHODS: A pilot randomized crossover field trial was conducted among 12 sawmill workers in southern Thailand under three conditions: no cooling (CON), a phase change cooling vest (VEST), and a combined cooling oasis (OASIS: hydration, fans, water dousing, cooling towels). Core temperature and heart rate were continuously monitored. Worker perceptions were explored through post-intervention focus group discussions. RESULTS: Compared with CON, OASIS reduced core temperature (-0.24°C; 95% CI: 0.23, 0.25) and heart rate (-7 bpm; 95% CI: 6, 9), while VEST reduced core temperature (-0.17°C; 95% CI: 0.17, 0.18) and heart rate (-5 bpm; 95% CI: 4, 6). Despite greater physiological benefits from OASIS, most workers preferred VEST due to ease of use and caused minimal disruption to workflow. OASIS was perceived as effective but interruptive. CONCLUSIONS: Combined cooling strategies can reduce heat strain in indoor industrial settings; however, the adoption of interventions is strongly influenced by practicality and economic considerations. Hybrid approaches and structural improvements are recommended. A full mixed-methods study is needed to evaluate effectiveness, productivity, and cost-effectiveness to inform scalable occupational heat policies.