The Howard Springs Quarantine Facility (HSQF) is located in tropical Northern Australia and has 875 blocks of four rooms (3,500 rooms in total) spread over 67 hectares. The HSQF requires a large outdoor workforce walking outdoor pathways to provide individual care in the ambient climate. The personal protective equipment (PPE) required for the safety of quarantine workers varies between workgroups and limits body heat dissipation that anecdotally contributes to excessive sweating, which combined with heat stress symptoms of fatigue, headache, and irritability, likely increases the risk of workplace injuries including infection control breaches.

The purpose of this study was the description of qualitative and quantitative assessment for HSQF workers exposed to tropical environmental conditions and provision of evidenced-based strategies to mitigate the risk of heat stress in an outdoor quarantine and isolation workforce.

The study comprised two components - a cross-sectional physiological monitoring study of 18 workers (eight males/ten females; means: 41.4 years; 1.69m; 80.6kg) during a single shift in November 2020 and a subjective heat health survey completed by participants on a minimum of four occasions across the wet season/summer period from November 2020 through February 2021. The physiological monitoring included continuous core temperature monitoring and assessment of fluid balance.

The mean apparent temperature across first-half and second-half of the shift was 34.7°C (SD = 0.8) and 35.6°C (SD = 1.9), respectively. Across the work shift (mean duration 10.1 hours), the mean core temperature of participants was 37.3°C (SD = 0.2) with a range of 37.0°C - 37.7°C. The mean maximal core temperature of participants was 37.7°C (SD = 0.3). In the survey, for the workforce in full PPE, 57% reported feeling moderately, severely, or unbearably hot compared to 49% of those in non-contact PPE, and the level of fatigue was reported as moderate to severe in just over 25% of the workforce in both groups.

Heat stress is a significant risk in outdoor workers in the tropics and is amplified in the coronavirus disease 2019 (COVID-19) frontline workforce required to wear PPE in outdoor settings. A heat health program aimed at mitigating risk, including workplace education, limiting exposure times, encouraging hydration, buddy system, active cooling, and monitoring, is recommended to limit PPE breaches and other workplace injuries in this workforce.