Former Fruitgrowers Chemical Company site, Māpua

The Fruitgrowers Chemical Company built its plant in 1932, in the centre of the village. According to Wikipedia, from the 1940s it made organomercury and organochlorine pesticides, including DDT, DDD, dieldrin, 2,4-D and paraquat, and organophosphates from the 1960s; by 1978 it was using 124 chemicals in 84 formulations. A minerals processor, Mintech, worked on the same site, and the two factories had their own landfill. When the plant closed in 1988 the soil, the groundwater, the Waimea Inlet and the estuarine sediments were contaminated, and the site was left with no liable party able to pay.

Tasman District Council became the owner between 1989 and 1996. In 1999 the government allocated 3.1 million New Zealand dollars. Taking the soil away would have meant many truck movements and was ruled out; in November 2001 a contract was signed to treat it on site by mechano-chemical dehalogenation (MCD), in which a ball mill grinds the soil finely and triggers the destruction of chlorinated compounds. Formal trials in 2004 showed that the plant brought soil within the acceptance criteria, but in one of them a breakdown led to the formation and release of small quantities of dioxin.

Between February 2005 and July 2007 about 8,000 m³ of soil went through the reactor, 30% more than the 6,161 estimated, at 83 m³ a week against the 108 in the contract. In all, more than 60,000 m³ was excavated and over 8,000 samples analysed; the site was capped with half a metre of residential-quality soil. The works took more than three years instead of 18 months and cost about 12 million New Zealand dollars instead of 6. In 2008 the Parliamentary Commissioner for the Environment published a critical investigation of the management, the emission controls and the groundwater, and recommended that New Zealand set up a system of independent environmental auditors.