The fire department has set up a special task force to investigate a fire on Wednesday night in a 47-year-old commercial-residential block in King's Road, Quarry Bay.
Initial inquiries suggest that a "chimney effect" had accelerated the fire, which was rated No 4 alarm, the second-most severe on emergency services' five-tier classification system.
The fire at the 25-storey Chung Hing Mansion was put out at around 2.30am yesterday morning, 4-1/2 hours after it broke out. Some 700 residents were evacuated from the building, which had been renovated recently.
Two of eight people affected by the fire, aged 59 to 96, were discharged from hospital. The rest, mostly overcome by smoke, were in stable condition.
The Fire Services Department said it deployed 200 firemen and ambulancemen, using 17 jets to fight the blaze. Two people familiar with the investigation both said a chimney effect in the air shaft accelerated the fire, which engulfed 60 to 70 apartments near the shaft on all floors.
Initial information showed that a flat on the 10th floor first set fire. The flat was badly burned, with a large hole left in the front door. Most of the furniture inside the flat was burnt. An apple with some burnt incent sticks was seen at the entrance.
A Mrs Chan, in her 60s, who lived with her husband opposite to the flat, said she saw her neighbours burning candle and incense sticks over two days to celebrate a religious festival.
"Now I am still quite scared. It is quite lucky to not have a few causalities as many elderly live here," Chan said.
A man who lived in the apartment where the fire started said he suspected there was a short-circuit in an electrical appliance. But this cause has been rejected by investigators.
Susan Khoo, 51, a Malaysian who lives on the 15th floor, said she found that lots of rubbish, including paint cans and debris from the renovation projects, had been left in the stairwell.
She suspected some of this refuse could have been set on fire by a smoker.
"There is rubbish on every floor. I am quite surprised."