The group included six men and eight women aged between 23 and 39, who consumed a hot pot dinner that used charcoal as fuel at a Beijing cuisine restaurant located on Lockhart Road, Wan Chai last night.

They developed symptoms including loss of consciousness, dizziness, vomiting, nausea, headaches, shortness of breath and palpitation around two hours after the dinner started, according to the Centre for Health Protection of the Department of Health.

The patients were sent to Ruttonjee Hospital and Queen Mary Hospital for treatment, while one of them sought medical treatment at Queen Elizabeth Hospital. Four of them were later transferred to Pamela Youde Nethersole Eastern Hospital for hyperbaric oxygen therapy.

Ten out of the 14 patients are now in stable condition, while the remaining four have been discharged.

A preliminary investigation showed while the air conditioner was turned on, the windows of the dining room and the door was also closed for a long period of time during the hot pot meal, which may have caused the increase in the carbon monoxide level inside the room.

The investigation is ongoing.

The center reminded members of the public to use vented fuel-burning appliances in a well-ventilated area. They should also seek medical attention immediately if suspected symptoms of carbon monoxide poisoning develop.