The Labour Department has reviewed the existing Heat Stress at Work Warning system and announced an enhanced arrangement yesterday (27 August). The new system links the warning more closely with the Hong Kong Observatory’s “Extremely Hot” special alert (issued when forecast or actual temperatures reach 35°C or above) and actual temperature readings. Oxfam Hong Kong (OHK) welcomes this move, considering the revision an effective step to increase the sensitivity of the warning mechanism and to address gaps in the current system and heat index, which have not fully reflected the risks faced by workers under extreme heat.

To better capture the heat stress experienced by outdoor workers across different districts and workplaces, and to strengthen protection measures, OHK has put forward three recommendations for the Labour Department’s ongoing review and research over the coming year:

1. Calculation of the Heat Index
The calculation method should more accurately capture the heat stress faced by outdoor workers, taking into account both direct sunlight and high humidity. OHK supports the Labour Department’s current adoption of a “dual‑track” approach, which combines the Hong Kong Heat Index (HKHI) and temperature thresholds. We urge the Department to complete research before next summer to incorporate the internationally recognised Wet Bulb Globe Temperature (WBGT) index, thereby refining the HKHI calculation to better reflect actual working conditions.

2. District‑based Heat Warnings 

The Observatory’s territory‑wide Very Hot Weather Warning and Extremely Hot Weather Special Alert are public advisory aimed at all citizens and must remain unified. By contrast, the Heat Stress at Work Warning is an occupational safety warning issued by the Labour Department, directed at employers and workers.

Data from both the Observatory and OHK show significant variations in heat stress across districts and workplaces. We therefore recommend introducing district‑based warnings (covering at least 18 districts) to reflect localised heat stress. In addition, high‑risk workplaces such as airport aprons and construction sites should be designated for mandatory installation of WBGT devices, enabling workers to plan work and rest schedules based on localised data. Mobile outdoor workers could adjust their arrangements according to district warnings.

3. Guidance Notes on Prevention of Heat Stroke at Work 

The Labour Department should clearly define the scope of application for the Heat Stress at Work Warning and related Guidance Notes. Beyond listing examples of occupations and workplaces, Japan’s approach could be referenced, using working hours in hot outdoor or indoor environments as a standard (e.g. continuous work exceeding one hour, or more than four hours per day). This would better cover occupations that are difficult to categorise, such as delivery staff, ensuring they receive appropriate protection during prolonged outdoor work.

We also recommend further study to include heat‑related illnesses in the list of occupational diseases. This would strengthen enforcement of preventive guidelines and safeguard workers’ health and safety. Meanwhile, we propose promoting the installation of WBGT systems at outdoor workplaces, with possible subsidies for purchasing the equipment. This would provide employers with scientific evidence to guide heatstroke preventive measures when necessary, while protecting the rights of both employers and employees in the event of disputes.

Conclusion:

OHK welcomes the Labour Department’s swift review and revision of the Heat Stress at Work Warning System, which demonstrates its commitment to safeguarding workers’ health. We believe the professionals will continue to improve the calculation method and system design, while promoting the gradual introduction of WBGT monitoring in workplaces. Looking ahead, we hope to see the establishment of a mechanism that more closely reflects district-level working conditions and can therefore be effectively implemented, so that workers’ safety and health could be ensured.

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For enquiries, please contact:

Dr Terry Leung
Director of Hong Kong, Macau, Taiwan Programme Unit, Oxfam Hong Kong
Telephone: (852) 3120-5144
Email: [email protected]

Ms Celine Chi
Social Development Research Officer, Oxfam Hong Kong
Telephone:(852) 3120-5298
Email: [email protected]