Towers from processing plant at Puhipuhi Mine, Northland
Image: DOC


DOC is responsible for potentially contaminated sites on public conservation land.

Contaminated sites are areas of land that have been used for mining, fuel and chemical storage, agricultural businesses, cemeteries, landfills, and a range of other activities.

Associated with these activities and industries, and varying from site to site, are substances including landfill material, heavy metals/metalloids (such as arsenic, mercury, cadmium, copper and lead), pesticides and various hydrocarbon compounds. These substances can become a problem when they occur at levels which may affect human health and/or the environment.

Contamination is not always limited to a specific site. Substances may leach through the soil into groundwater, or be carried to nearby land and water ways in rainwater runoff or as dust.

Some of these sites have not been in use for decades – or even more than a century – while others were more recently mothballed or vacated by previous owners.

In many cases, DOC has inherited these sites as they are within land the department is responsible for. In other cases, we administer or manage small strips of land in coastal or natural environments adjacent to sites where heavy industry has occurred – but the operation has been shut down and the previous operator has left the site.

Managing contaminated sites

As a responsible land manager – and with a duty of care to ensure the health and safety of people who visit the areas we manage – we’ve begun a long-term work programme to address the issues associated with these sites.


The first step for DOC is to prioritise the sites – we need to determine which ones need the most urgent attention. We’ve already identified the top sites in each region where the most planning and work will be needed.

From that list we’ve identified the top few sites in each region. We plan to investigate and determine the level of risk at each site. Once that work is completed, we will have several options available – including management of the sites, or remediation. We’ll be focussing on the top priority sites over the next 10 years.  


We have planning work underway for Oamaru Gasworks, Little Tahiti landfill and Ocean Beach in the South Island, and Puhipuhi mine in Northland.

We also expect a consistent flow of new information about these sites through investigations, and that will be a key factor in our planning for this work, and the delivery of on-the-ground management and remediation activities.

You can request site-specific information, but what we have available will vary from site to site, and it may take time to compile.

It is possible we will need to temporarily restrict public access to some of these sites to ensure the health and safety of visitors – and our staff and contractors.


For further information please email with the subject line: Contaminated sites

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