A fire simulation conducted to investigate the rapid spread of last year’s deadly apartment complex blaze in Tai Po has found that non-fire-retardant materials may have caused “secondary ignitions” that exacerbated the spread of the inferno. Wang Fuk Court in Tai Po on December 10, 2025. Photo: Kelly Ho/HKFP. Testifying at a public hearing investigating the cause of the fire that killed 168 and displaced thousands last November, Richard Yuen, chair professor of architectural engineering at the City University of Hong Kong, said it was likely that scaffold netting around the estate at the time was not fire retardant.
In the test, carried out at the Fire Safety College of Sichuan University of Science and Engineering, it only took minutes for the fire to surge to the top of a three-storey structure meant to simulate conditions at Wang Fuk Court, the site of the deadly blaze.
A sample taken from the estate’s only undamaged building, Wang Chi House, burned up fully when it was ignited in the test. Yuen said it was “very likely” the sample was not fire retardant.
Yuen also said that the non-fire-retardant scaffolding nets could have caused “secondary ignitions” that exacerbated the spread of the blaze by lighting wooden planks, foam boards, and bamboo poles on fire.
Fireproof windows removed
In another experiment, fireproof windows, which were removed to allow workers more convenient access to the buildings’ exterior, were able to block temperatures of up to 1,061 degrees Celsius, Yuen said.
The committee had previously heard the openings allowed toxic smoke and fumes to enter the emergency staircases, accelerating the spread inside the buildings and trapping residents. Earlier hearings also revealed that residents made complaints to multiple government departments before the fire. Wang Fuk Court on April 22, 2026. Photo: Kyle Lam/HKFP. Lead counsel for the committee Victor Dawes previously said that initial investigations found that the blaze was most likely caused by workers smoking, while flammable construction materials may have contributed to the rapid spread of fire and smoke.
The presence of combustibles and use of non-fire-rated construction materials were the ultimate factor behind the rapid spread of the blaze, Yuen said on Wednesday.
Yuen said the simulation found that fire-retardant nets would not ignite, adding that the fire might have gone out on its own if proper nets were used.
Fire Services Department Assistant Director Yiu Men-yeung, testifying after Yuen, attributed the high death toll to several reasons including the deactivated fire alarm system, inaccessible escape routes, and vision-obstructing foam boards.
Yiu, who also leads the government’s interdepartmental investigation task force, told the committee that more than 90 per cent of the deceased were found in Wang Cheong House and Wang Tai House, the two buildings that were the first to set ablaze.
Most of the victims in Wang Cheong House retreated to their flats and died there after they found that the emergency stairs were not a viable means of escape, Yiu said. The bodies of people in Wang Tai House were mostly found on lower levels, where they found the exits were blocked by fallen debris, he added.