Dow Paritūtū site / Taranaki Regional Council

This page outlines the history and legacy of the Dow site at Paritūtū, provides an overview of the roles and responsibilities of key stakeholders in relation to current and future management and outlines the next steps for the site.

The Dow Paritūtū agrichemical manufacturing site occupies a 16 hectare land parcel located between Paritūtū Road and Centennial Drive in north-western New Plymouth. The site and associated operations have been of ongoing interest to the local community as a result of concerns raised around the potential environmental and human health impacts of activities carried out at the site over the past 60 years.

Background

Ivon Watkins commenced manufacturing agricultural chemicals at the Paritūtū site in 1960. Four years later, the Dow Chemical Company acquired a 49% stake in Ivon Watkins to create Ivon Watkins-Dow Ltd. Following a number of company changes, Corteva Agriscience NZ Ltd became the owner and operator of the Paritūtū site in 2019, whilst Dow retained aspects of the environmental liability for the site. Corteva announced the closure of the site the following year.

Dow Chemical (NZ) Ltd will assume ownership of the site in the first quarter of 2023. Dow has committed to undertaking a full detailed site investigation and remedial works, as required. No future use of the site has been proposed at this stage. Future use will be the subject of further discussion with regulatory authorities, iwi/hapū and the community as the site investigation evolves.

Dow Paritūtū site, New Plymouth. The site boundary is indicated by the yellow line.

Community involvement in future of site

Three hapū and two iwi have an association with Paritūtū. It is a shared interest area between Taranaki Iwi and Te Atiawa; Ngāti Tairi Hapū and Ngā Mahanga (Taranaki) and Ngāti Te Whiti Hapū (Te Atiawa) have associations with the Dow Paritūtū site. It is understood urupā are located on the property, which was also a papakāinga (settlement) and a battle ground. The property sits within a broader cultural landscape of significance.

Iwi and hapū have a special relationship with Paritūtū, and have expressed a strong interest in being engaged in the investigation and remediation project, including ongoing direct communication with Dow.

The area is also of interest to the wider community, given its proximity to both a residential area of New Plymouth and to Back Beach, a popular recreation area.

Consents & compliance monitoring

Demolition of site infrastructure took place from mid to late 2022. While no further manufacturing is to be undertaken, Dow continues to hold two resource consents for the Paritūtū site: one to discharge stormwater to the Herekawe Stream at Back Beach (expiring 2026) and another to discharge contaminants to air (expiring 2044).

The current compliance monitoring programme for the site, undertaken by Council, includes regular site inspections, odour surveys, biomonitoring of the Herekawe Stream, and an annual marine survey of the northern end of Back Beach. For more detailed information, see annual compliance monitoring reports.

Remediation action plan

In November 2022, Dow and Corteva jointly announced the sale of the Paritūtū site to Dow. Site demolition to ground level was completed in December 2022. Dow will assume full ownership and responsibility for the ongoing management of the site, with the intention of undertaking site investigations and the development of a remediation plan. Dow has its own remediation team, which has extensive international experience in contaminated site investigation and remediation. It has also secured New Zealand-based contaminated land experts from Tonkin+Taylor to assist with delivery of the project.

On 21 November 2022, Dow and Tonkin+Taylor presented a draft remediation roadmap to the regulatory authorities and iwi/hapū for discussion. This roadmap is still in draft, awaiting formal feedback from stakeholders. It sets out, at a high level, a plan to take the site from demolition through to ongoing use. Interim steps include undertaking sampling and testing, risk assessment, consenting and planning, to develop a remediation plan based on the test results and compliance with regulatory requirements.

The project is long-term and expected to take a number of years to complete. The geology and hydrogeology at the site are complex. A thorough and complete site investigation is essential to ascertain the level of contamination, where it is located and the mechanisms by which contamination can move around in the environment.

Early work involving planning and site investigations is likely to take between two and four years to complete. Site remediation will be guided by the findings of the earlier investigations, and will likely take a further two to four years to complete. Depending on the remediation solutions selected, aspects of the remediation may continue beyond that timeframe. These time frames are estimates only and will depend on the complexity of the site, the nature of any contamination, and available options to remediate the site.

Tonkin + Taylor has been engaged by Dow to complete a site investigation and develop a remediation plan for the Paritūtū site. Click here for their website which provides information about the project.(external link)

Taranaki Regional Council (TRC) and New Plymouth District Council (NPDC) as the regulatory authorities, with iwi/hapū, will work alongside and in consultation with Dow throughout the life of the project. Dow has proposed that iwi/hapū and the wider community will have opportunities to have input into the development of remediation goals for the site as the project progresses.

TRC, NPDC and iwi/hapū have appointed Beca to independently review any work undertaken by Dow.

Any independent technical advice commissioned by the Council will be sought and secured independently of Dow however, where appropriate, we will seek reimbursement to keep costs to the community to a minimum.

To read a full overview click here [PDF, 720 KB].

Summary (external link)of Preliminary Site Investigation Paritūtū, New Plymouth [PDF, 15 MB]. Tonkin+Taylor, July 2024

Summary of soil and groundwater evaluations Paritūtū site, New Plymouth, New Zealand. [PDF, 7.5 MB] Groundwater Technology, 4 July 1996

Summary of soil and groundwater evaluations Paritūtū site, New Plymouth, New Zealand Appendices Part 1 of 2. [PDF, 20 MB] Groundwater Technology, 4 July 1996

[PDF, 24 MB]Summary of soil and groundwater evaluations Paritūtū site, New Plymouth, New Zealand Appendices Part 2 of 2. [PDF, 24 MB] Groundwater Technology, 4 July 1996

Investigation of alleged agrichemical waste disposal sites in New Plymouth - Part 1 [PDF, 11 MB], Taranaki Regional Council, August 2001

Investigation of alleged agrichemical waste disposal sites in New Plymouth - Part 2 [PDF, 11 MB], Taranaki Regional Council, August 2001

Dioxin Concentrations in Residential Soil, Paritūtū, New Plymouth [PDF, 3.6 MB], Pattle Delamore Partners Ltd, 26 September 2002

A Study of 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) Exposures in Paritūtū, New Zealand [PDF, 3.9 MB], Report to the New Zealand Ministry of Health, February 2005

Marfell Park, New Plymouth, Environmental Investigation, [PDF, 1.6 MB] Pattle Delamore Partners Ltd, August 2009