The evidence, much of which was unseen until the hearing began on Thursday, showed that "almost all life-protecting fire safety appliances failed because of human errors", leading counsel Victor Dawes told an independent committee conducting the probe.

The government counsel is expected to outline its response at a later date in the hearings.

Here are key takeaways from the evidence presented in committee leading counsel's opening address:

- Residents' complaints -

For years, residents of Wang Fuk Court repeatedly complained to the Hong Kong Labour Department about construction workers smoking, but received little response.

The Labour Department carried out at least 16 inspections but concluded the smoking complaints could "not be justified" and referred the complaints to the Fire Services Department, who said the issue did not fall within their remit.

In its fire safety inspections, the Labour Department also only examined the flame-retardant qualities of scaffolding netting through documents, without any on-site testing.

It claimed that it lacked the necessary expertise on fire-resistant netting and that responsibility lay with the Buildings Department.

"If departments have conflicting positions and if no department feels that the matter's under their jurisdiction, then how and where can complainants complain? And if the complaints are not addressed, how can they follow up?" Dawes said.

- Netting and cigarettes -

Substandard construction safety netting and cigarette butts are the focal points of the probe into the causes of the fire and its rapid spread.

The contractor only ordered one batch of flame-retardant netting. The rest was cheaper netting with no fire resistance.

The committee saw text messages by a surveyor at the Housing Bureau's Independent Checking Unit (ICU) notifying a contractor before an official inspection of the netting.

Staff members also disclosed the purpose of inspections, giving the construction firm an opportunity to "tamper with" testing results, Dawes said.

The Fire Investigation Task Force believes that an ignited cigarette caused combustible material to catch fire, sparking the blaze.

Evidence showed that workers had been smoking on a rooftop, while police found remains of cardboard boxes, garbage and cigarette butts at a light well where the fire was believed to have started.

- Alarm system failed -

Fire alarm systems for seven of eight blocks had been deactivated, which "greatly shortened the time for residents to evacuate," Dawes said.

Required fire-retardant nets were not used in many places, and the windows were covered by foam boards, which may have contributed to the spread of fire into the flats, the panel heard.

While the staircase and corridors were meant to serve as potential escape routes, the windows had been removed to allow workers to easily climb in and out of buildings.

The open accesses meant smoke and fire was able to spread more rapidly, trapping residents.

Footage released at the hearing showed that the fire spread to seven buildings within 90 minutes on November 26, while the blaze took 43 hours to be fully extinguished.

- Firefighter's death -

Video presented at the hearing showed some of the last minutes of firefighter Ho Wai-ho, who went up one of the towers in response to an emergency call.

CCTV clips showed him entering a building with two other firefighters and stopping to assist residents who were evacuating, then entering and exiting a lift.

Minutes after issuing a mayday call, Ho likely smashed a window on the 31st floor in an attempt to escape and fell to his death, Dawes said.

He was found in an open space with multiple fractures and lacerations, and taken to hospital, where he was shortly pronounced dead.

Autopsy showed that Ho had inhaled a significant amount of carbon monoxide.

- Victims -

Of the 168 people who died in the fire, 110 were women and 58 men, aged between six months and 98 years old.

The victims included 150 residents, nine migrant domestic workers, seven construction workers, one firefighter and one visitor.

The hearing was told 37 households lost more than two family members.

Those injured were aged between three months and 87 years old.

The complex housed more than 4,600 residents, 1,700 of them over the age of 65.