Asbestos may have been released into the air near schools and homes after a consultant wrongly claimed the carcinogenic substance was not present in a government building before demolition work began.
The government is investigating after ordering a halt to demolition at 21, 23 and 25 Borrett Road in February. The Mid-Levels site is less than 100 metres from the English Schools Foundation's Island School, the Carmel Jewish day school and several kindergartens.
Work was stopped when Environmental Protection Department inspectors found the harmful substance in pipes and trunk cable sealants in a building at the former government residences. A registered asbestos consultant's report had said the blocks were free of asbestos.
Inhaling asbestos can cause lung cancer, asbestosis and mesothelioma, and the International Labour Organisation estimates it causes 100,000 deaths each year. Blue and brown asbestos has been banned in Hong Kong since 1996.
The department declined to name the consultant or give an opinion on whether the mistake was a result of negligence. But it confirmed that no air-quality monitoring for asbestos had been carried out during the demolition, which was the usual practice if the block had asbestos.
Questions remain on how long the demolition work had gone on for - it is believed to have started in mid-January. It is also unclear how many people worked on the site and whether any precautions had been taken to protect them.
'As the case is still under investigation, which might lead to legal action, no further details will be disclosed,' the department said.
Cheung Kong (Holdings) bought the site for HK$11.6 billion through its subsidiary Bristow Investments in June last year. The developer said three and a half floors in one of the 17-storey blocks had been removed. One storey had been removed from each of the other two.
It blamed contractor Hung Key Cheong Yip for providing 'misinformation', leading to the confusion. The contractor has since instructed another consultant to carry out a new assessment for approval. Work resumed on Monday.
Cheung Kong said air monitoring tests by the contractor showed no impact on air quality. The department had monitored five spots weekly, all of which were within 100 metres of the site. Results showed a low risk of asbestos exposure.
But an independent asbestos consultant, Lee Yarnall, said assessments taken after demolition stopped did not necessarily prove that there had been no exposure. 'This could only have been accurately measured by air testing [at the time],' said Yarnall, a director of consultancy Aspec.
Yarnall estimated that removing the asbestos from Borrett Road might cost up to HK$3 million.
The owner of a building or a contractor must hire a qualified consultant and laboratory to carry out an assessment. Breaking the law can result in a HK$200,000 fine and six months in jail.