OBJECTIVE: Describe the relation between clinic visits for symptoms of heat-related illness (Heat-Related Visits, HRV) and ambient Heat Index among aluminium smelters in the Arab Gulf States. METHODS: Four smelters provided HRV data. Meteorological data from nearby airports provided data for Heat Index (HI). Three approaches to finding a smelter-specific trigger for heat stress management were examined. RESULTS: The rate ratios from Poisson regressions were 1.2/°C for one smelter, 1.1/°C for two others and 0.96 (not significant) for the fourth
all showed no carry-over effect from preceding day. Using a logistic distribution provided a reasonable trigger. CONCLUSIONS: HRVs increased with the Heat Index for three of the four smelters. In this limited study, the trigger point based on the logistic distribution at p = 0.05 was the most protective.