Cheminova was not born a pesticide company. The civil engineer Gunnar Andreasen founded it in Copenhagen in 1938, making anti-rust treatments at a factory at Sydmarken 10–12 in Mørkhøj, north of the city. The German occupation cut off the raw materials, so the firm improvised, turning out replacements for raw rubber and sugar and thinners for paint and varnish — the improvised chemistry of a country cut off from its suppliers. Twice in the last winter of the war, Danish resistance groups struck the plant. Holger Danske sabotaged the factory on 2 January 1945, and BOPA hit it again on 14 February. In 1943, in the middle of all this, Andreasen signed over every Cheminova share to Aarhus Universitets Forskningsfond, the Aarhus University Research Fund. When the war ended and German chemical patents were released to the Allies, Cheminova built a new plant at Måløv Byvej 229–233 and turned to insecticides.

Måløv did not work out. Neighbours and the local authority complained about what the plant's wastewater was doing to the water environment, and by 1953 Cheminova was looking for somewhere with fewer neighbours. It found Harboøre Tange: a sandspit roughly ten kilometres long, strung between the Limfjord and the North Sea, joining the villages of Harboøre and Thyborøn. There was a second attraction. A salt dome lies beneath Rønland, and chlorine — extractable from salt — was a key ingredient in the company's products. One of the first things Cheminova bought after the move was a salt extraction plant. It was decommissioned almost immediately, when the local authority refused permission to sell the surplus salt and the arithmetic collapsed. The pesticide plant stayed, and is still there today.

Høfde 42 was a municipal chemical waste dump, and between 1957 and 1962 Cheminova used it heavily. The permit covered three types of waste. What actually went into the dunes and the sea, according to later accounting, was more than a hundred different substances, solid and liquid, from pesticide production. The inventory that remains buried there is specific and unpleasant: roughly 70 tonnes of parathion — the organophosphate sold in Denmark as Bladan, a smell Danes who grew up on farms still write about — along with about 10 tonnes of malathion, 6 tonnes of sulfotep, and 7 tonnes of mercury. Parathion and its relatives were Cheminova's main business for years. The company has since phased out its most toxic products, but what was buried in the 1950s does not phase out.

The people who forced the issue were not regulators. A local fisherman known as Rav-Aage started noticing dead fish and sick gulls, and kept saying so. Biology students from Aarhus University took up the work and gave the complaints the weight of measurement. It took years, and the first result was partial: in the early 1980s a small fraction of the depot — 5,600 cubic metres — was dug out and removed. The rest stayed. By 2006 the authorities had settled on containment rather than removal, driving about 600 metres of steel sheet piling eleven metres down to ring the core of the contamination, capping it with a plastic membrane and holding the groundwater level inside under active control. The wall was guaranteed to function through 2021.

Region Midtjylland put the cost of removing the ground contamination at Høfde 42 at a quarter of a billion kroner in 2014 — the same year that the American FMC Corporation bought Cheminova outright for roughly 8.5 billion kroner from Auriga Industries, which had held the company since its 1986 flotation. In December 2020 the Danish state allocated 630 million kroner over five years to deal with the country's so-called generational pollution sites, of which Høfde 42 is the most notorious, with 125 million of that coming from Auriga. The chosen method is thermal: heat the buried mass to 350 degrees in place and break the compounds down. Sixty-odd years after the last barrel went into the sand, the dunes at groyne 42 are finally being taken apart.