Hong Kong investigators are piecing together how the city’s worst fire in decades rapidly raged through seven high-rise buildings, leaving at least 159 people dead, dozens injured, and more than 30 still missing.

Investigators found that protective green-mesh netting installed around the Wang Fuk Court complex, which was undergoing extensive renovations, did not meet flame-retardant standards.

Amid calls for transparency and accountability, Hong Kong’s leader, John Lee, has ordered a judge-led committee to investigate the fire and review oversight of building renovations. Hong Kong’s anti-corruption body has also launched its own investigation.

Here is what we know about the blaze and how it spread so quickly.

How did the fire start?

This is not yet known, though a number of residents had reportedly complained of construction workers involved in the renovation project smoking cigarettes on site.

The fire broke out at Wang Cheong House, one of eight identical 31-storey residential towers at the Wang Fuk complex, which was built in the 1980s.

The first call to the fire brigade came at 2.51pm on Wednesday, November 26, Hong Kong time (5.30pm AEDT).

Social media footage captured the fire’s early stages as the green mesh netting and bamboo scaffolding covering the building rapidly ignited.

The fire spread quickly up the side of the building, and within minutes the entire block was alight.

As it took hold, burning debris began to fall to the ground. Within minutes, fire had spread to seven of the eight buildings, which form a V-shape that extends out towards several other skyscrapers.

Some 750 firefighters tried to quell the flames and rescue hundreds of residents trapped inside. The high temperatures prevented firefighters from entering the buildings, said Hong Kong deputy fire chief Derek Armstrong.

The Leungs, a married couple in their 70s who lost their apartment in the fire, recounted to Reuters how they were having afternoon tea at a nearby restaurant when their daughter alerted them to the fire.

“It all happened within just an hour or two. I stood there watching as one block after another went up in flames – my legs felt so weak I could hardly stand,” Mrs Leung said, choking up with tears.

“When I saw it, I felt completely helpless. I still don’t understand how the fire could spread so fiercely, devouring one building after another.”

“The bamboo scaffolding cracked, and there was banging that sounded like exploding windows – the flames were completely out of control.”

One man told this masthead that no alarm had sounded, and that he had been alerted to the emergency by neighbours banging on his apartment door.

What caused it to spread so quickly?

Hong Kong police have said the exterior walls of the complex’s buildings “had protective nets, membranes, waterproof tarpaulins, and plastic sheets suspected of not meeting fire safety standards”.

Investigators also suspect other materials, such as Styrofoam-type panels used to protect windows from damage during the renovation work, were not properly fire-resistant.

One Wang Fuk Court resident, Lau Yu Hung, 78, told The New York Times that many of the windows in his block were covered with a thin layer of polystyrene foam.

The material blocked out much of the light and prevented residents from seeing outside, he explained. It was only because of a small gap in the foam covering the bathroom window that he had been able to see that a neighbouring building was on fire and escape in time, he said.

Strong winds also fanned the flames and may have prevented helicopters from being used in the firefighting effort.

According to Bloomberg, inspections had flagged risks well before the disaster. Regulators conducted 16 checks on the renovation project and issued repeated written warnings urging the contractor to put proper fire-prevention measures in place, including as recently as last week, according to Hong Kong’s Labour Department.

At least 15 people have been arrested on manslaughter charges as the fire investigation proceeds, including two directors and one engineering consultant from a construction firm, Hong Kong Police have said.

On December 2, officials said they had completed searching for bodies in the interiors of the buildings and would now focus on other areas.

The search may take weeks due to the hazardous conditions and difficulty in collecting bodies and human remains, some of which have been found on rooftops and stairwells.

What type of buildings were they?

Wang Fuk Court is a complex of privately owned, government-subsidised housing in the Tai Po district of Hong Kong’s New Territories, close to the northern border with mainland China.

Built in the 1980s, the basic apartments measure 40 to 45 square metres, according to online real estate listings. Like most of Hong Kong’s high-density housing, they appear not to have been equipped with smoke detectors or sprinkler systems.

The buildings were also constructed before revisions to the city’s fire codes required mandatory fire refuge floors.

Hong Kong’s 7.5 million residents mostly live in cramped apartments crammed on scarce flat land or perched on the slopes of steep mountainsides. Many of those high-rise buildings are crowded together.

How does this fire compare to Grenfell Tower?

The 2017 Grenfell Tower fire was one of the United Kingdom’s worst modern-day disasters.

Seventy-three people died when a fire, which started in a malfunctioning fridge, engulfed a 23-storey west London tower block, fuelled by flammable metal cladding that had been added to the exterior during renovation work.

A six-year public inquiry eventually exposed a range of regulatory failings of building standards and fire safety stretching back decades. A criminal investigation into a number of organisations, companies and individuals connected to the disaster is ongoing.

In both disasters, graphic imagery quickly captured news feeds around the world. But while they appear to have superficial similarities, there are also significant differences.

At Grenfell Tower, the fabric of the building itself – Polyethylene-filled aluminium composite cladding added during renovation work – was found to be the root cause, rather than exterior scaffolding or temporary sheeting.

In many high-rise buildings, including Grenfell Tower, shelter-in-place (or “stay put”) is a common fire safety standard. However, it becomes ineffective when an unimpeded fire spreads up the outside of a building. This happened at Grenfell Tower and in Hong Kong.

And in another possible parallel with Hong Kong, combustible foam insulation added to window frames at Grenfell Tower was found to be a significant factor in helping the fire to spread.

Helping the survivors

More than 2600 residents have been put in temporary accommodation, the government has said, with 1013 residents staying in hostels, camps or hotel rooms. Another 1607 residents have moved into transitional housing units.

“I can’t sleep at night, thinking about my home. Everything that I have earned for decades is gone,” said Mrs Leung.

Her 41-year-old daughter, Bonnie Leung, said it was “unfathomable that such a tragedy, so many deaths, can happen in Hong Kong”.

The fire was deadlier than one in November 1996, when 41 people died in a commercial building in Kowloon in a blaze that lasted for around 20 hours. A warehouse fire in 1948 killed 176 people, according to the South China Morning Post.

With AP, Reuters

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