Gasworks building contamination reviewed

The old gasworks building in Humber St, Oamaru, where erosion has exposed historic contamination....
The old gasworks building in Humber St, Oamaru, where erosion has exposed historic contamination. PHOTO: HAMISH MACLEAN
The Department of Conservation is working closely with KiwiRail, the Otago Regional Council and the Waitaki District Council to investigate the historic contamination of the former Oamaru gasworks site, Doc Geraldine operations manager Duncan Toogood says.

KiwiRail confirmed over a week ago the old gasworks building in Humber St would be demolished. The only contamination in the building was asbestos contamination, strategic land use general manager Stephanie Campbell said, and KiwiRail had no plans for the site.

However, a regional council regulatory committee agenda from January lists the site as one of four in the region where ongoing work to address the effects of legacy contamination was required. It states site investigation took place in 1998, and in 2000 about 45cu m of contaminated material was removed, "but significant contamination remains on site''.

"Over the past 18 months, erosion along the foreshore has affected the stability of the site, exposing additional contaminants.''

ORC senior environmental officer Simon Beardmore said most of the site was contained within Section 28 Block III of Oamaru.

"Section 28 is owned by KiwiRail and the esplanade reserve is the responsibility of the Department of Conservation. The coastal erosion is currently confined within the reserve managed by Doc, however, if left unmanaged, it will eventually encroach into the land owned by KiwiRail. It is hoped that both government agencies will work together to remediate the site.''

Mr Toogood said the gas-making facility, operating from 1876 to 1980, had left "significant historical contamination''.

"While originally thought to be owned by the Waitaki District Council, the public esplanade was never vested in the Oamaru Borough Council as planned in the 1870s. Following the discovery of the contamination, research has uncovered the esplanade reserve remains in Crown ownership.

"I have visited the most exposed part of the site and have seen the visible seepage of waste which is exposed to the air and sea. Doc is concerned about the potential environmental impacts of the contamination and the risks it may present to sea birds and other marine life if the site is left unmanaged.''

Mr Beardmore said although a detailed review of options for site management or remediation had not been completed, the council expected "reinstatement of the rock wall is likely to be key to preventing further erosion and exposure of contaminants''.

"Removal of contaminated boulders and soil may be necessary to accommodate a new coastal structure. This may provide the opportunity to remove contaminants from the surface of the site ... and contain them beneath the structure.''

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