The Independent Committee investigating the deadly Tai Po fire in November heard on Friday that the use of “inappropriate” access doors, known locally as sang hau, was the primary cause of thick smoke infiltrating the emergency escape routes, trapping residents and exposing critical failures in regulatory oversight.

During the second day of the public hearing, Victor Dawes, leading counsel of the committee, explained that the staircase windows of the residential buildings were converted into the so-called sang hau, temporary openings used by renovation workers to access external walls for maintenance.

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According to outsourcing subcontractor submissions, they were instructed to create these openings on every fifth floor, and used flammable wooden doors instead of aluminum boards, as instructed by the main contractor Prestige Construction and Engineering Co Ltd, which violated fire safety regulations.

The Buildings Department's submissions stated that the access doors violated multiple regulations and were “inappropriate”.

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Dawes also questioned the Housing Bureau’s Independent Checking Unit's responsibility, as it only conducted random document checks for the sang hau construction applications and carried out no site inspections, resulting in a failure to understand the modifications or the consequences.

“Sang hau critically affected residents’ escape routes. Which department will supervise and inspect them, or will it be left solely to contractors to decide? This needs to be reviewed in the future,” he said.

Contact the writer at stacyshi@chinadailyhk.com