Hong Kong heat stress warning system gets new triggers as Labour Dept acts on criticism
SCMP · 8 SOURCESabout 1 hour ago3 MIN
Summary
Hong Kong's Labour Department unveiled an enhanced Heat Stress at Work Warning system on Thursday, with new measures taking effect the following day. Commissioner for Labour Sam Hui Chark-shum introduced two key modifications following widespread criticism that the three-tier Amber-Red-Black system had failed to issue Red or Black warnings in its three years of operation, even when temperatures exceeded 39 degrees Celsius in some areas earlier this month .
Key Points
- When temperatures measured across many parts of Hong Kong reach 35 degrees Celsius or above, the warning level will automatically escalate by one tier—from Amber to Red, or from Red to Black .
- The second modification lowers triggering thresholds whenever the Hong Kong Observatory issues an Extremely Hot Weather Special Alert, permitting earlier escalation to higher warning levels .
- Under the new framework, during an Extremely Hot Weather Alert, a Red warning will be triggered when just two monitoring stations reach a heat index of 32—down from four stations previously—yet even during recent extreme temperatures, monitoring stations only recorded indices of 30 to 31.8 degrees .
- The system uses the Hong Kong Heat Index rather than the internationally recognised Wet Bulb Globe Temperature standard, a decision the Labour Department defended by stating the local index is more sensitive to humidity and better suited to Hong Kong's subtropical climate .
- Deputy Labour Commissioner (Occupational Safety and Health) Chiang Chi-ho explained the revamped system now operates on a "three-pillar" approach, with the existing heat index as the base evaluation supplemented by the two new trigger conditions .
- Industry representatives including Hong Kong Construction Industry Sub-contractors Association president Ng San-wa urged authorities to mandate full work stoppages during Black warnings without distinguishing between labour intensity levels, arguing that construction workflows are interconnected and the expected one to two Black warning days per year would have minimal impact on overall project timelines .
- Labour Federation president Lam Chun-sing welcomed the changes but noted that under Black warnings, only "very heavy labour" and "heavy labour" categories are required to stop work, recommending this protection be extended to "medium labour" workers such as outdoor cleaners .
- Former Observatory director Lam Chiu-ying acknowledged the improvements as progress but maintained the system retains an "unscientific defect" by continuing to use the Hong Kong Heat Index rather than adopting the internationally recognised Wet Bulb Globe Temperature standard .
Why It Matters
With climate change driving more frequent and severe heatwaves, Hong Kong's revision of its worker protection framework signals recognition that existing safeguards were inadequate for modern extreme weather conditions . However, critics argue that without converting these guidelines into legally binding requirements, employers—especially those facing project deadlines and potential penalties for delays—will continue to lack sufficient motivation to protect workers from heat-related health risks .
With climate change driving more frequent and severe heatwaves, Hong Kong's revision of its worker protection framework signals recognition that existing safeguards were inadequate for modern extreme weather conditions . However, critics argue that without converting these guidelines into legally binding requirements, employers—especially those facing project deadlines and potential penalties for delays—will continue to lack sufficient motivation to protect workers from heat-related health risks .