Three workers were rescued from a water treatment plant in Tuen Mun after they became trapped in a smoke-filled underground pipe during a fire yesterday.
The three men, aged between 30 and 43, were unconscious when firefighters brought them to the surface, the Fire Services Department said. They were in critical condition in Tuen Mun Hospital's intensive-care unit last night.
Another two men, aged 35 and 49, complained of feeling unwell from smoke inhalation and were treated in the same hospital.
The five workers are employees of Water Supplies Department contractor Ming Hing Construction Company. The fire broke out in the department's water treatment plant in Fu Tei Road, Tuen Mun, at about 2.45pm yesterday.
"An initial investigation showed the blaze broke out in an underground tank and smoke spilled into the pipe where three workers were carrying out repairs," the department said.
A total of 115 firefighters and paramedics were deployed to the scene, and 26 fire engines and six ambulances were dispatched. More than 70 people were evacuated from the site, police said.
It is understood the firefighters managed to douse the flames quickly, but it took about three hours to carry out ventilation work and complete a search in the confined area to ensure no one was left trapped inside.
The fire, water and labour departments are investigating the cause of the accident.
The Water Suppliers Department said it would look into whether workers followed safety requirements and proper procedures at the site.
Water treatment works at the plant were suspended last month because of repair works, the department said. The repair works were expected to be completed as early as next month.