Hong Kong construction site blaze mostly put out after burning for 40 hours

Emergency personnel were unable to access the basement area of the site, where they said they believed the fire started, for more than a day. Drones were deployed for aerial surveillance and robots sent to assist firefighters during the marathon bid to gain the upper hand.

Authorities also mobilised seven water jets and two breathing apparatus teams.

At its peak, the fire was upgraded to a No 4 alarm. Fires in Hong Kong are rated on a scale of one to five, with five the most serious.

The Fire Services Department said earlier that explosions had occurred in the basement, possibly linked to oxyacetylene cylinders.

The large size of the site, at 70 metres by 80 metres (230 feet by 262 feet), had complicated efforts to tackle the fire, the department said.

The basement was also like a maze and contained a large number of wooden boards and building materials, it said.

Hong Kong building where deadly fire erupted is warren of flats and businesses

The cause of the blaze is still under investigation. No casualties have been reported but residents nearby were forced to close their windows to avoid the plumes of thick smoke entering their flats.

The site is for a Housing Society dedicated rehousing estate at Phase 2 of the Hung Shui Kiu/Ha Tsuen New Development Area.

The scheme was expected to be completed in 2026 and provide 962 subsidised flats for sale.

The society said it would consider reinforcing two tower cranes at the site, or disassembling and replacing them, after the site was reopened.

A separate fire on Wednesday broke out in a 60-year-old tenement building killing at least five people and injuring 43 others.