Calls for system review after lowest alert in force during record-breaking heat

Hong Kong authorities are facing calls to review the heat stress warning system after it remained at the lowest level during the city's hottest day on record, with temperatures reaching 36.9 degrees Celsius (98.4 Fahrenheit). Labour unionists and a leading meteorologist suggested that heatstroke should be recognized as a work-related injury, granting workers compensation.

The scorching heat, influenced by Typhoon Dolphin, prompted temperatures of up to 39.8 degrees in Sheung Shui, the city's highest since automated weather stations were introduced in the 1980s. Chau Sze-kit, chairman of the Construction Industry Employees General Union, criticized the system, stating the amber heat stress alert appeared "mocking" the extreme conditions.

The heat stress warning system considers air temperature, humidity, wind speed, solar radiation, and hospital admission figures to assess heat stress. Employers must provide extra rest periods and hydration breaks for workers under amber alerts, while red and black alerts require suspending or halting work. Since its implementation in May 2023, only amber warnings have been issued, with no red or black alerts.

Former Observatory director Lam Chiu-ying proposed using a more comprehensive measure like the wet-bulb globe temperature to determine heat stress. However, concerns were raised about the difficulty of determining whether an incident was caused by heatstroke or a worker's pre-existing conditions.