‘Lost’ report reveals pollution at controversial New Plymouth chemical plant

The extent of soil contamination at the controversial New Plymouth chemical plant has finally been revealed after a “lost” report from the late 1990s resurfaced.

The Taranaki Regional Council (TRC) released the soil and groundwater assessment report with the permission of multinational chemical giant Dow Chemical.

It was part of the 1996 Environmental Assessment Project (EAP) for Dow Chemical’s former manufacturing facility in Paritutu.

Investigations have shown that soil contamination levels in some areas are more than 450 times higher than previously confirmed groundwater contamination levels.

When the Truth and Reconciliation Commission investigated the Ivon Watkins plant in Buller Street, New Plymouth in 1996, the levels were more than 1400 times higher than the acceptable level for the plant, based on overseas benchmarks.

Dioxin researcher Andrew Gibbs said the new information in the rediscovered report reinforced the view that current investigations of the Paritutu site should be extended to neighbouring Centennial Park.

The Paritutu site was dismantled in 2022, and Dow and its New Zealand-based remediation partner, Tonkin & Taylor, are conducting a cleanup operation that is expected to take several years.

Tonkin & Taylor has completed a preliminary site investigation (PSI) which has been submitted to the TRC and is currently undergoing an independent review by consultant firm Beca Group.

Ivon Watkins – later Ivon Watkins-Dow – produced the herbicides 2,4,5-T and 2,4-D in Paritūtū from 1960 to 1987.

These herbicides contain toxic dioxins, the main ingredient in Agent Orange, a defoliant used by the U.S. military in the Vietnam War that has been linked to cancer and birth defects.

Any contamination found in the PSI would be expected to be low, given the average half-life of the chemical is 46 days (the time required for 50% breakdown as stated in the 1996 EAP).

Lost report found

A “lost” soil and groundwater assessment summary was leaked to Gibbs, but it did not include soil test data.

Gibbs and Radio New Zealand asked for the full report but were initially told it could not be found.

Abby Matthews, director of environmental quality at the Truth and Reconciliation Commission, said the report, which was stamped “confidential,” was never “lost” because it was always in the files, just not where it was expected.

“It appears that this report was refiled into the wrong bin, probably because our filing system changed in the late 1990s.

“We have no way of knowing when it was last seen.”

Dow Chemical did not respond directly to Radio New Zealand’s questions about why it did not publish soil contamination data in 1996, but pointed out that Current Site Survey.

“These are great questions,” the company said in a statement.

“(That’s why) Dow is committed to a detailed study of current environmental conditions at the Paritutu mine, rather than relying on information that is, in many cases, outdated.

“Our goal is to obtain and utilize current, accurate data rather than guessing what might have been discovered or said decades ago.”

The TRC reviewed and accepted the findings, conclusions and recommendations of the 1996 EAP report, but Matthews said the TRC was not responsible for releasing the data contained in the report.

“Dow (then DowElanco) voluntarily commissioned the 1996 report and shared it with the Taranaki Regional Council for information. The press release dated 27 September 1996 was also written and issued by Dow (then DowElanco),” she said.

In June, According to RNZ Documents leaked to Gibbs suggest the current investigation may need to expand beyond the confines of this location.

Gibbs argues that groundwater contamination found at the northern boundary of the site could have been caused by a former off-site pool of liquid waste at the base of the Paritutu Rock.

The leaked documents are part of an EAP report that TRC, which owned the 16-hectare land at the time, informally requested from Dow in the 1990s and include a 1994 hydrological survey, a missing 1996 soil and groundwater assessment summary (minus soil data) and a 2020 groundwater management report.

In 1997, the Truth and Reconciliation Commission sold the Paritutu mine to Dow Chemical Company for $1.7 million.

A year ago, Dow’s EAP report indicated that groundwater at two locations on the site was contaminated with low levels of phenoxy and chlorophenols, with contamination levels below 15 ppm (parts per million).

By comparison, the US Environmental Protection Agency’s guideline for New Zealand’s marine environment is 30ppm.

Investigators identified Test Hole 39 on the western boundary of the site and Test Hole 42 on the northern fence line as areas of concern.

Dow’s focus is on groundwater contamination, and it stressed that the contaminants pose no risk to employees or nearby residents, and will not reach the coastline, which is now a marine park.

It did not test for dioxins.

In a 1996 media release, the group said: “In soil, dioxins bind to the clay and do not migrate with groundwater, so they pose no threat to the environment.”

What the report shows

Drill logs from the complete soil and groundwater assessment showed high concentrations of phenoxy herbicides and related chlorophenol chemicals were found in soil in 13 test holes.

The most contaminated area is the western border, where chemical drums have historically been discarded.

In test well 39c, phenoxy herbicide levels of 5521.5 ppm and chlorophenol levels of 1806.5 ppm were found.

This is well above what the TRC calls Buller Street’s “clean-up” level of 5ppm.

More than 80% (4659 ppm) of the contamination in well 39c was 2,4,5-T and 2,4-D, components of Agent Orange.

The report also showed that 13 groundwater testing holes were contaminated.

The highest levels of phenoxy and chlorophenol were found in test well 39J, at 14.5 ppm and 1.5 ppm, respectively, while well 42 had levels of 6.5 ppm and 1.4 ppm, respectively.

Dow’s modeling suggests that contaminated groundwater at concentrations above the laboratory detection limit of 0.03 ppm – the lowest level that can be found in tested samples – would not reach the coast.

The soil and groundwater assessment described borehole 42 as a “point source” – by one definition, it is a single identifiable source of contamination from which contaminants are discharged – but the contaminants were below laboratory detection limits within 100 meters of the borehole.

The report recommends covering the contaminated soil with an impermeable seal to prevent further infiltration of rainwater into the site’s aquifer.

Report of great significance – Dioxin researchers

Gibbs said the details revealed in the “missing” assessment report were significant.

“First, high concentrations of Agent Orange components 2,4-D and 2,4,5-T were found in the soil behind the west side of the plant, where the TRC reported that barrels of the chemicals had been dumped and their contents had leaked into the soil.

“These conditions have never been reported before and are much higher than the reported water table levels.”

He said the report strengthened the argument that current site investigations should be extended to neighbouring Centennial Park.

“The second highest level of groundwater contamination was near the old pond at the north end of the plant, but they did not find any soil contamination there.

“This is really compelling evidence that the groundwater contamination is a legacy of the discharge ponds from the 1960s.

Gibbs believes that these ponds are not just for cooling water as some have said, but can also be used to discharge wastewater that flows into the back beach.

Taranaki Regional Council responds

Abby Matthews, TRC’s director of environmental quality, said the council had previously said it was “not aware of soil contamination on the (Paritūtū) property,” referring to the building where 2, 4, 5-T is produced.

There was never any testing done there.

She reiterated that the Truth and Reconciliation Commission was concerned about groundwater contamination.

“Environmental risks arise from the potential for contaminants in groundwater to migrate beyond property boundaries.

“To this end, the company and the city council agreed to expand the groundwater monitoring network and implement additional monitoring.

“The purpose of the groundwater program is to detect any contaminants that migrate toward the perimeter of a property, as well as track any changes in contaminant levels over time.”

Asked if further testing should be done at Centennial Park, near the site boundary, Matthews pointed to the current site investigation.

“Dow’s initial and subsequent detailed site investigations were conducted by Tonkin and Taylor.

“Beca is currently reviewing their report independently on behalf of New Plymouth District Council, the iwi, the hapu and ourselves and the report will be available shortly. The report will compile all available information about the site.”

Dow’s response

In order to conduct a comprehensive and accurate analysis of the site, the first step is to prepare a preliminary site investigation report, which will be released soon, Dow said in a statement.

As requested by the Truth and Reconciliation Commission and indigenous peoples, the public safety initiative is being reviewed by independent experts selected by the Truth and Reconciliation Commission and indigenous peoples.

It said the move was intended to fill any testing and data gaps identified during the preparation of the PSI, including those raised in the RNZ questions.