Hong Kong’s Labour Department added two triggers to its workplace heat-warning system in late August, in a move intended to better reflect heat stress caused by high temperatures, strong heat radiation, humidity and limited air movement. The changes are also intended to cover poorly ventilated indoor workplaces, rather than focusing only on outdoor conditions.
Labour Commissioner Sam Hui said the warning system itself is not law, but employers still have legal duties under occupational-safety requirements to assess and manage risks including heat exhaustion and heatstroke. Employers should make advance risk assessments and consider measures such as cooling stations, fans, improved ventilation, shade and cooling clothing.
They should also consider moving heavy work away from the hottest hours, Hui said. A heat warning should not automatically be treated as an instruction to halt all work: whether work continues should depend on the protective measures in place and the priority given to workers’ health risks.
The authorities are retaining a locally adjusted approach rather than relying solely on the international Wet-bulb Globe Temperature index. The reports said the authorities considered that using the index alone might not fully reflect humidity and poor air circulation in Hong Kong workplaces, although the final role or weighting of the index has not been specified.
Hui said the department would review data from the current summer and consider further adjustments or additional elements before the next summer or hot season. The review does not yet have a specified publication date.
Hui also said he was open to discussing whether heatstroke should be classified as an occupational disease. Any such move would require clear legal criteria and medical evidence establishing a causal relationship between the illness and specific workplace conditions.
The Labour Department said it was willing to work with unions to help workers obtain medical evidence concerning suspected work-related heatstroke. It is also considering a reference database based on medically verified past cases, but no decision or timetable has been given.