Asbestos found at St George's Hospital has been contained and does not pose a health hazard, the Canterbury Earthquake Recovery Authority (Cera) says.

Cera chief executive Roger Sutton said the authority knew the building contained asbestos before demolition started, and asbestos was removed by Nikau Demolition as the building came down.

Demolition rubble at the site was monitored for asbestos, and small traces had been secured.

Sutton said the Canterbury District Health Board was confident the particles left in the rubble did not pose a risk to the hospital's staff, visitors, patients or neighbours.

The Ministry of Health had been informed, he said.

A Nikau spokesman said the asbestos was in the fine matter at the site and was situated at particular spots. Plenty of water and tarpaulins were stopping the asbestos from getting in the air.

Monitors around the perimeter would indicate if asbestos was escaping, he said.

Material contaminated with asbestos would eventually be dumped at a special site at the Kate Valley landfill in North Canterbury.

Asbestos has been an issue as the city's buildings have been demolished since the February 2011 earthquake.

A large dump in a KiwiRail warehouse in Cass St, Sydenham, has been identified as an asbestos risk.

The operators of the dump, now closed, did not notify authorities of the possible asbestos problem.

Department of Labour southern general manager Jean Martin said the department had received 320 notifications of hazardous work involving the removal of asbestos in Canterbury between the February 2011 quake and June 18 this year.

"Our construction inspectors have identified that asbestos issues tend to stem from sites that have not notified the department of the hazardous work being undertaken," she said.

"The predominant reason for this is usually the failure of the contractor scoping the work to identify or suspect [then test for] the presence of asbestos."

The department was yesterday unable to provide the number of sites where asbestos had been identified by its inspectors but not notified by site operators.

It was helping contractors identify hazards, including asbestos, with training workshops due to finish next week, Martin said.

It had recently established a team of health and safety inspectors whose focus was solely on the Canterbury rebuild and recovery. "The department wants to ensure that workers in the Canterbury rebuild are not injured, killed or contract occupational diseases as a result of inadequate health and safety systems in the workplace," she said.

Once the department was notified about asbestos, a decision was made on the ensuing process, taking into account previous work by the company and how the asbestos could be removed.

Environment Canterbury told The Press this week that it had received allegations about 44 demolition dump sites since February and had prosecuted the owners of two.

It had issued 15 abatement notices relating to seven sites and had issued one infringement notice.

The remainder of the sites had been investigated and the investigation closed or an investigation was still in progress.

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