Report: pesticide firms withheld studies on harmful effects

Swiss-based Syngenta was bought out by the ChemChina group in 2017. Keystone / Patrick Pleul

Four pesticide manufacturers, including Swiss-based Syngenta, for years withheld studies showing potential harmful effects of certain products, an investigative journalism team has revealed.

A total of nine pesticides were subject to so-called DNT studies by the manufacturers in the 2000s, whose results were not submitted to European Union (EU), wrote Swiss public media SRFExternal link on Thursday.

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SRF collaborated on the journalistic research with the Bayerischer Rundfunk, Spiegel (both Germany), the Guardian (UK), and Le Monde (France) media outlets.

The Swiss broadcaster said one of the pesticides was “Vertimec Gold”, an emergency pest-killer used on crops and which contains the abamectin insecticide.

In spring this year, the EU renewed the approval for abamectin, but restricted its use further, based on Syngenta studies from 2005 and 2007 – which only recently came to light – showing adverse effects of the chemical on rats.

Switzerland is currently examining whether to correspondingly tighten its rules on abamectin.

Serious concerns

According to the journalists, and to a Swedish medical researcher who first uncovered the missing tests, there has been an obligation under EU law to report all available adverse data on products since the early 1990s.

Internal EU documents seen by the journalists suggest officials in Brussels have “serious concerns” about the missing studies.

Syngenta told SRF it had not infringed any obligations, and that the studies in question were done to satisfy demands of US regulators, before being subsequently required by EU authorities. The company added that the studies did not raise any new adverse findings.

The pesticide manufacturers involved also include Germany’s Bayer, Japan’s IKS and Nissan Chemical Corporation.