​The Labour Department (LD) announced today (August 27) that with effect from tomorrow (August 28), the Heat Stress at Work Warning (HSWW) system will be further enhanced to better safeguard the occupational health of employees working under hot weather or in high-temperature environments.
      
     To cope with the extremely hot weather due to climate change, the LD has promptly reviewed and enhanced the existing HSWW system on top of its original functions to enhance the warning alert under abnormally high temperatures.
      
     The enhanced system will introduce two new conditions for triggering different levels of HSWW. First, when the "Extremely Hot Weather" Special Alert issued by the Hong Kong Observatory (HKO) is in effect, the monitoring threshold for triggering a higher level of warning will be lowered, enabling the early activation of a higher level of warning. Second, when the measured temperatures generally over Hong Kong reach 35 degrees Celsius or above, apart from lowering the monitoring threshold for triggering a warning, the warning level will be raised by one level automatically (i.e. from Amber Warning to Red Warning, or from Red Warning to Black Warning), in order to alert the public of the health risks of heat stress when working under abnormally high temperatures. For details of the enhanced system, please refer to the annex.
      
     Since the establishment of the HSWW system in 2023, the LD has maintained communication with stakeholders and listened to their views. The LD has also continuously reviewed and enhanced the system as appropriate by making reference to information and advice provided by other departments, including the HKO, to suit the actual circumstances of Hong Kong. Since 2024, when the HKO issues the "Extremely Hot Weather" Special Alert, the LD will issue an Amber Warning even if the index has not reached the level for issuing the HSWW, to take into account the hot weather conditions. From this April, in addition to using the Hong Kong Heat Index measured at the monitoring station at King's Park, the LD has added the indices measured at the other nine locations as issuing criteria of the HSWW, enhancing the coverage and sensitivity of the system. After the launch of the enhanced system, the LD 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.
      
     The enhancement of the system will not impose additional work for employers and employees. They should continue to pay heed to the level of the HSWW issued by the LD and make corresponding work arrangements. Employers shall conduct heat-stress risk assessments for employees working in hot environments, and based on the assessment results and the risks of heat stroke faced by employees at different levels of the HSWW, implement the heat stroke prevention measures recommended in the Guidance Notes on Prevention of Heat Stroke at Work, including rescheduling work periods, setting up shade covers, providing ventilation and heat dissipation equipment, and reminding employees to replenish their water and rest in a timely manner. In addition, employers should keep assessment records and explain the assessment results to employees and give appropriate instructions to ensure that employees take an appropriate amount of rest according to the assessment results to minimise the heat stress at work.
      
     The LD also encourages and motivates employers to arrange on-site heat-stress risk assessments, taking into account the special circumstances of their work nature and workplace (such as geographical locations and specific working environments). They can also seek assistance from occupational health professionals, and take appropriate preventive measures based on the results to reduce the risk of heat stroke at work.
      
     The LD reminds employers that they may face prosecution if they endanger the health of employees without providing suitable heat stroke prevention measures. The LD also enhances inspections and enforcement actions targeting workplaces with a higher risk of heat stroke to safeguard the occupational safety and health (OSH) of employees.
      
     Employees should also pay attention to their own physical condition and inform their employer if they feel unwell. When necessary, they can call the LD's OSH complaint hotline at 2542 2172 or submit an online OSH complaint form (eform.cefs.gov.hk/form/ld0001/en/) to seek assistance from the LD.
      
     The LD disseminates the HSWW levels to members of public through multiple channels, including the "iAm Smart" and "My Observatory" mobile applications, government press releases, the HKO's official website, and major media platforms. For the HSWW and related guidelines, please refer to the LD's thematic webpage: www.labour.gov.hk/eng/news/prevention_of_heat_stroke_at_work.htm.

Ends/Thursday, August 27, 2026
Issued at HKT 14:00

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