Preventing carbon monoxide poisoning in Hong Kong’s workplaces: Employers’ obligations

Summary

The Hong Kong Labour Department published Guidance Notes (17 Dec 2025) on preventing carbon monoxide (CO) poisoning at work. CO is a colourless, odourless and highly poisonous gas often produced by fuel-powered engines, heaters and appliances used in poorly ventilated spaces. The guidance sets out a hierarchy of controls employers should follow: identify sources, eliminate or substitute fuel-powered equipment, employ engineering and administrative controls, monitor air quality and provide training and detectors.

Key Points

Identify all potential CO sources in the workplace before deciding controls.
Eliminate or substitute fuel-powered equipment where possible (use electric, hydraulic or pneumatic alternatives).
Use engineering controls: direct venting, local exhaust ventilation (LEV) and increased general ventilation with a dedicated fresh-air supply and directional airflow.
Do not rely solely on natural ventilation (opening windows/doors) for significant CO emissions.
Apply administrative controls: ban idling engines indoors, limit exposure time, use warning signs and provide training on CO risks and symptoms.
Implement regular monitoring and air-quality testing and install CO detectors with audible/visible alarms where exposure risk exists.
Maintain equipment and ventilation systems; stop using malfunctioning equipment and follow manufacturers’ instructions.
Operate generators and engine-driven equipment outdoors at least 5 metres away from building openings and air intakes.
Employers are legally obliged under the Occupational Safety and Health Ordinance (Cap. 509) and the Factories and Industrial Undertakings Ordinance (Cap. 59) to provide, so far as reasonably practicable, a safe working environment.
CO exposure is acutely dangerous: about 0.4% (4,000 ppm) can cause unconsciousness and death within minutes.

Context and relevance

The guidance responds to the ongoing risk posed by fuel-powered appliances and engines used in workplaces—common in logistics, catering, construction and industrial settings. It reinforces an international trend toward stricter on-site air quality and occupational-safety practices, and gives employers practical, legally framed steps to reduce acute poisoning incidents and compliance risk.

Why should I read this?

Look — if you run or manage a workplace in Hong Kong (or look after workers who use engines, heaters or generators), this is one of those must-do reads. It tells you exactly what to check, what to fix, and what you absolutely shouldn’t ignore (like where to put a generator). Saves you from guessing and, frankly, could save lives.

Author style

Punchy: the article distils the Labour Department’s practical guidance into clear actions employers must take. If you’re responsible for workplace safety, the detail matters — this isn’t optional reading.