Objective To investigate the association between work-related injuries and temperature, to identify the groups of workers at high risk of heat-related injuries, and to explore the possible lagged effects of extreme heat on work-related injuries.

Method Workers’ compensation claims data obtained from SafeWork South Australia for the period of 2001–2010 were transformed into time series format and merged with daily meteorological data. The impacts of temperature on daily work-related injury rates were estimated by using generalised estimating equation model with negative binomial distribution, a log link function and a first order autocorrelation structure. A piecewise linear spline function was utilised to quantify the effect of temperature on work-related injury rates below and above thresholds. The day of the week and long-term trends were adjusted.

Result Overall, there was an association between work-related injuries and temperature in South Australia. One degree Celsius increase in temperature below 38 was associated with 0.2% increase of injury rate. However, the injury risk declined significantly above this temperature. Specifically, the following groups of workers were at high risk of heat-related injury: male workers (IRR 1.004, 95% CI 1.002–1.005); and young workers aged < = 24 (IRR 1.003, 95% CI 1.000–1.006). Occupations at risk were labourers and related workers (IRR 1.004, 95% CI 1.001–1.006), intermediate production and transport workers (IRR 1.002, 95% CI1.000–1.004), and tradespersons and related workers (IRR 1.003, 95% CI 1.001–1.006). Industries showing an association between injuries and temperature were agriculture (IRR 1.007, 95% CI 1.002–1.013), construction (IRR 1.005, 95% CI 1.002–1.008), finance, property and business services (IRR 1.006, 95% CI 1.001–1.012), and overall outdoor industries (IRR 1.004, 95% CI 1.002–1.006). A lagged effect of extreme heat on work-related injury rates has not been found.

Conclusion The risk of work-related injuries is significantly associated with heat exposure, especially for vulnerable groups in the workplace.