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Asia heatwave: Hong Kong introduces new guidance and warning system to prevent heat stroke at work

Asia heatwave: Hong Kong introduces new guidance and warning system to prevent heat stroke at work


Employers and employees are advised to be aware about the three levels of 'Heat Stress at Work Warning' when working under hot weather conditions.

The Labour Department (LD) of Hong Kong has introduced Guidance Notes on Prevention of Heat Stroke at Work and Heat Stress at Work Warning effective 15 May 2023, reminding employers and employees to take appropriate measures to prevent heat stroke when working in hot weather or hot environments.

The Guidance Notes document is applicable to:

  • Work conducted in outdoor locations without shelters;
  • Work conducted in indoor locations without air-conditioning system installed;
  • Work conducted near heat sources or heat-generating facilities.

According to the Occupational Safety and Health Ordinance, employers are required to provide or maintain a system of work that is, so far as reasonably practicable, safe and without risks to health. A spokesperson for the LD said employees working under hot weather or in hot environments may have an increased risk of heat stroke. Employers should assess in advance the risk factors for heat stress in employees at work, and formulate preventive and control measures for the different risk factors, including the scheduling of appropriate work-rest periods, so as to reduce the risk of heat stroke posed to employees in hot environments.

The spokesperson added, "Since the nature and requirements of different industries and job positions vary, employers and employees should make reference to the guidance notes in advance and adopt a risk-based and consultative approach to devise reasonable and mutually acceptable work-rest schedules under different levels of the Heat Stress at Work Warning."

To enhance employers and employees' understanding of the level of heat stress in outdoor or indoor working environments without air-conditioning under hot weather, the LD has introduced three levels of Heat Stress at Work Warning based on the Hong Kong Heat Index:

heat stress at work warning en

The notifications of Heat Stress at Work Warning will be disseminated via the "GovHK Notifications" or "MyObservatory" mobile applications, government press releases, the Hong Kong Observatory's webpage and the mass media. When the Heat Stress at Work Warning is in force, hourly updates will be sent out automatically. If the Heat Stress at Work Warning reaches a higher level, an earlier update will be issued.

Employers have to make appropriate arrangements for rest periods based on the level of physical exertion in work in the hour following the announcement of the Heat Stress at Work Warning and the hourly updates announcing the continued effectiveness of the warning.

The LD spokesperson reminded that since weather changes are unavoidable natural phenomena, employers should not unreasonably withhold wages, attendance awards or allowances for employees who have extra rest time given under the Heat Stress at Work Warning. Employers should also observe their statutory responsibilities and requirements under the Occupational Safety and Health Ordinance, the Factories and Industrial Undertakings Ordinance, the Employment Ordinance, the Employees' Compensation Ordinance and the Minimum Wage Ordinance.

According to the Guidance Notes, to prevent employees from suffering heat stroke while working, employers can implement the following preventive and control measures:

  • The person responsible for the workplace must ensure that there is sufficient cool drinking water available for employees, and should arrange for their employees to have access to drinking water within 10 minutes of walking. In general, employers should provide employees with about 250 to 500ml of drinking water per hour. If employees are at high risk of heat stress while working, they should be advised to drink approximately 250ml of cool drinking water every 15 to 20 minutes, which is about 750 to 1,000ml of cool drinking water per hour, but no more than 1,500ml of water per hour. Employers may consider providing drinks with electrolytes such as sodium ions and potassium ions.
  • For work processes performed under high heat, such as metal melting and casting, employers must install appropriate mechanical devices, such as exhaust systems and insulation, to regulate the temperature of the employees’ work area, and provide suitable personal protective equipment for heat protection and insulation.
  • Employers/responsible persons should provide shade or cover, or consider the appropriate use of sunshade/parasol, to block the sunlight for employees who work outdoors for extended periods.
  • Employers should install air conditioning system, blowers or misting fans, or provide portable fans to facilitate heat dissipation for employees.
  • If employers need to provide work clothes for employees, they should provide light-coloured, thin, and loose-fitting clothing as far as possible. Furthermore, employers should provide appropriate sun protection equipment for employees, e.g. wide-brimmed hats, safety helmets with neck shades, cooling towels, sun protection sleeves that have good sweat-wicking and dry-fit properties, etc.
  • Employers/responsible persons should provide suitable mechanical aids for employees to use, or instruct employees to take other appropriate measures to minimise physical exertion. If employees need to engage in heavy physical work for long periods or at a rapid pace, they should be arranged to rotate work or have different employees to perform the work in turn.
  • Employers should arrange an appropriate acclimatisation period to allow the employee to fully adapt to working in a hot environment.
  • In hot summer days, employers should schedule outdoor and physically demanding work to cooler daytime periods (e.g. before 10 a.m. or after 4 p.m.) as far as reasonably practicable. Alternatively, they can arrange for employees to work alternately in hotter and cooler environments.
  • Employers should let employees performing light to moderate levels of physical work have a minimum of a 10-minute rest break after every two hours of work, while employees performing heavy to very heavy levels of physical work should be given at least a 15-minute rest break after every two hours of work. If the Heat Stress at Work Warning is in effect, employers should provide more rest time as recommended. Employers can divide the required rest breaks into shorter but more frequent periods, depending on the working conditions.

More details of the Heat Stress at Work Warning and the relevant guidance notes can be found on the LD's webpage or the Occupational Safety and Health Council's dedicated webpage.

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Lead image / HKSAR Government Press Releases (R-L: Vincent Fung, Deputy Commissioner for Labour (Occupational Safety and Health); and Catherine Wong, General Manager of the Occupational Safety and Health Council)

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