The relationship between outdoor thermal conditions and acute injury in an aluminum smelter

The health and safety records at a smelting operation in the Midwest were reviewed to extract data relating to acute injury for the years 1997-1999, inclusive. For the purpose of this study, acute injury is defined as all first aid and recordable cases that are the direct result of a specific event. The objective was to assess the effect of outdoor thermal conditions on the occurrence of acute injury while also considering the factors of work location within the smelter and workers' age. The results indicated a significant relationship between outdoor thermal category based on heat index, age category, and the occurrence of acute injuries. Work location did not show a significant relationship with the occurrence of acute injuries. As compared to the reference thermal category of 16 °C (60 °F) and 21 °C (70 °F), there were significantly (p<0.05) elevated odds ratios associated with outdoor thermal conditions less than −7 °C (20 °F) and greater than 32 °C (90 °F). The injury rates for different work locations were consistent with job demands in those locations, although the odds ratios were not statistically significant. Finally, there was a significantly elevated odds ratio for younger workers, which appears to be related to the practice of assigning workers with less seniority to more demanding work locations.