The government is being asked to step in and force a multi-national agri-chemical business to clean up its New Plymouth production site - which the local mayor has described as a "ticking time bomb".
The Paritutu agrochemical plant in 1968. Photo: CC / Phillip Capper
Mayor Neil Holdom fears Corteva Agrisciences - previously the agricultural arm of DowDupoint - could walk away from the Paritutu plant leaving ratepayers with a remediation bill in the tens of millions of dollars.
Corteva has recently closed the 16-hectare site which borders Paritutu Centennial Reserve and residential housing.
Under previous management, it produced the herbicide 2,4,5-T which has been linked to health concerns.
From the 1960s through to 1987, Ivon Watkins (later Ivon Watkins-Dow) made the herbicide 2,4,5-T at Paritutu - which contained the toxic dioxin TCDD.
In the mid '80s, elevated levels of TCDD were found in the soil on the site's boundaries with reserve land and a residential street.
In 1998, similar levels were found on Mt Moturoa some distance away.
Dioxins are insoluble and break down very slowly in soil, if at all.
New Plymouth Mayor Neil Holdom - with the backing of Taranaki iwi - has written to Environment Minister David Parker asking the government to put pressure on Corteva to assess the site and remove any contaminated material.
Holdom told the minister the area had "experienced various and significant exposure to highly toxic chemicals over decades".
"What we've got there under the ground is a ticking time bomb and what we really want is Corteva to dig it up and take it off to a high-temperature incinerator in Europe and dispose of it safely, so that we're not left with the legacy of the activities there which have made them hundreds of millions of dollars over the years."
New Plymouth Mayor Neil Holdom has written to the environment minister, with support from Taranaki iwi, asking for the government to put pressure on Corteva for assessment of the site. Photo: RNZ / Robin Martin
Holdom wanted the site drilled and comprehensively tested.
Although there were examples of Dow subsidiaries paying to remediate production sites around the world, Holdom feared without government pressure Corteva could leave the New Plymouth site as it was.
"In a nutshell if Corteva, which is a $35 billion United States agri-company can sell that site then any liability or connection they have with all the legacy toxic chemicals on the site essentially transfer either to the person that buys it or to the people of New Plymouth district."
Holdom estimated it would cost between $50 million and $60m to make the site safe.
The plant is in the Taranaki iwi rohe. Its chair, Leanne Horo, echoed Holdom's fears.
"We know that this site was used to manufacture 2,4,5-T resulting in production of dioxin and that the contamination of the soil poses a risk to our future generations, our communities, and our environment, and it is important that we ensure that this situation is resolved by removing the contamination.
"It is important that this site is remediated."
But Environment Minister David Parker said responsibility to ensure the site was safe did not fall with the government.
"It falls with the district council and the regional council between them, probably in the main with the regional council, to make sure they have all the information they need to make these assessments and if they haven't got it to ask for the additional information, and if it's not provided promptly to go onto the site and do their own investigations."
Environment Minister David Parker says he expects Corteva to co-operate with the relevant authorities. Photo: RNZ / Angus Dreaver
He expected the company would co-operate fully.
"The councils will decide what further investigation is needed if there is an absence of information about parts of the site, and the owner of the site, which is a subsidiary of one of the largest and oldest chemical companies in the world, will act responsibly to clean up the site properly before they leave."
In a statement, Taranaki Regional Council (TRC) said Corteva was compliant with all its current consents.
TRC science manager Victoria McKay said it had removed all product from the Paritutu site, cleaned it thoroughly and validated the process through testing, and ongoing monitoring programme remained in place, including annual stormwater sampling and four on-site inspections.
"The TRC was not aware of any soil contamination on the property," McKay said, although the council has previously acknowledged there were no records for soil contamination under the building where 2,4,5-T was made.
She said a change of land use at the site would trigger a requirement for further investigation.
"Any future development or subdivision would need to meet the requirements of the National Environmental Standards for Assessing and Managing Contaminants to Soil to Protect Human Health, with site investigations by suitably qualified environmental professionals required to demonstrate suitability for that purpose."
Under the Resource Management Act, New Plymouth District Council would be responsible for ensuring that the site was suitable for the proposed new land use.
Corteva did not respond to RNZ questions.
Last year it said it would work with authorities to ensure the Paritutu site was managed appropriately whatever future use was decided upon.
