Rediscovered Report Unveils Severe Soil Contamination at New Plymouth Chemical Plant

A long-lost report has recently surfaced, revealing alarming levels of soil contamination at the former Dow chemical plant in New Plymouth, New Zealand.

The report, missing since the late 1990s, was part of a 1996 Environmental Assessment Project (EAP) conducted at the Paritūtū site. Its findings are significant, showing contamination levels far higher than previously disclosed, raising concerns about the site's environmental legacy.

The Taranaki Regional Council (TRC) released the report after securing permission from Dow, the multinational chemical giant that once operated the facility. The report, titled Soil and Groundwater Evaluation, indicates that soil contamination at certain site areas was more than 450 times higher than the previously acknowledged groundwater contamination levels. Even more startling, the contamination exceeded acceptable levels—based on international standards—by over 1400 times.

This revelation is particularly troubling given the plant's history. From 1960 to 1987, Ivon Watkins-Dow, the facility's original operator, manufactured herbicides at the site, including 2,4,5-T and 2,4-D, both components of Agent Orange. This toxic defoliant, used extensively during the Vietnam War, has been linked to severe health issues, including cancers and birth defects.

Dioxins researcher Andrew Gibbs, who had been investigating the site, first learned of the lost report through a leaked summary. The summary did not include soil testing data, leading Gibbs and others to press for the document's release. Initially, the TRC claimed the report could not be found, but it was eventually located, having been misfiled in the council’s archives.

The full report revealed high levels of contamination, especially on the site's western boundary, where chemical drums were historically discarded. In some areas, soil contamination was more than 5000 parts per million (ppm) for phenoxy weedkillers and over 1800 ppm for chlorophenols, far exceeding the 5 ppm "clean-up" level set by the TRC during a 1996 investigation of a similar site.

These findings significantly affect the ongoing cleanup efforts at the Paritūtū site. The plant was demolished in 2022, and Dow, along with its New Zealand remediation partner, Tonkin & Taylor, is in the midst of a multi-year cleanup process. A Preliminary Site Investigation (PSI) has been completed and submitted to the TRC for independent review by consultants Beca Group.

Gibbs believes the rediscovered report strengthens the case for extending the investigation into neighboring Centennial Park, arguing that the contamination may have spread beyond the site's original boundaries. The report also raises questions about the extent of the contamination's impact on the surrounding environment, including the possibility of contamination seeping into nearby groundwater.

Dow has responded to the report's findings by emphasizing its commitment to current and accurate data collection, rather than relying on decades-old information. The company stated that its ongoing environmental study aims to provide a comprehensive site analysis, addressing gaps in previous investigations.

The TRC has reiterated that its primary concern is groundwater contamination, which poses a risk of spreading beyond the site. As part of the ongoing investigation, the council has expanded its groundwater monitoring network, but questions remain about whether additional soil testing should be conducted in adjacent areas like Centennial Park.

This rediscovered report is a critical piece of the puzzle in understanding the environmental impact of the Paritūtū site. Its findings underscore the importance of transparency and thorough investigation in managing contaminated sites. As the cleanup process continues, the report will likely play a pivotal role in shaping the future of environmental remediation efforts at this controversial location.