‘Baffling’ work heat stress warnings to be revamped after record temperatures trigger only lowest alerts

Hong Kong's Labour Department plans to overhaul its heat stress warning system following record temperatures that only triggered the lowest alert. Former weather official Lam Chiu-ying has criticized the current mechanism as "baffling" and "decorative" after it issued only the lowest "amber" level during a recent heatwave. The Labour Department's Heat Stress at Work warning system currently consists of amber, red and black alerts, recommending various rest arrangements for employees working outdoors or without air conditioning.

However, none of these recommendations are legally binding upon employers. Hui stated that his department will collaborate with the Observatory to enhance the sensitivity of the warning system to "unusually high temperatures". The revamp is expected to be completed this summer. The Hong Kong Heat Index, which determines the level of the warning, considers factors like air temperature, humidity, wind speed, and solar radiation.

Since the 1950s, heatwaves have become more intense and frequent due to human-caused climate change, increasing the risk of lethal heat stress. Hong Kong's temperature has risen by 1.7 degrees Celsius since the Industrial Revolution, with heat and humidity potentially becoming lethal by the end of the century, according to a 2023 study.