Hong Kong revises heat stress warning system after criticism

Hong Kong's Labour Department has updated its Heat Stress at Work Warning (HSWW) system, introducing two new trigger conditions to better safeguard workers against extreme heat. This move comes after significant public criticism that the previous system's thresholds were too high, leading to no alerts being issued even during the city's hottest day in 143 years.

The enhanced system, effective Friday, will lower the warning thresholds when an "Extremely Hot Weather" Special Alert is active from the Hong Kong Observatory. Specifically, when temperatures reach 35 degrees Celsius or above, the system will automatically escalate the warning level by one step, from amber to red, or red to black. This addresses concerns that the previous amber warning was frequently activated without reflecting the severe conditions faced by outdoor laborers.

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truly baffling

Previously, the HSWW system faced scrutiny as record temperatures only triggered the lowest-tier amber warning, with red and black warnings never being activated. Experts, including former Observatory chiefs, pointed out the Labour Department's reliance on the Hong Kong Observatory's Heat Index, which is designed for the general public, rather than a measure like the wet-bulb globe temperature that accounts for humidity and other factors critical for outdoor workers.

While the department has not yet adopted the wet-bulb globe temperature, it stated it will consider it for future improvements. The Association for the Rights of Industrial Accident Victims welcomed the amendments, believing they will increase the system's sensitivity. However, they urged the department to review the enhanced system within a year and consider making the rules binding for employers, a point that remains a significant gap in worker protection.

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After the launch of the enhanced system, the Labour Department will continue to review the operation of the system and make improvements, such as studying whether to include other monitoring data, for example, the Wet Bulb Globe Temperature, as one of the indicators of the system.