Press release | 01.07.2020 | sn

Banned in the EU, Permitted in the USA

The history of the herbicide atrazine is a story about the different ways of dealing with knowledge and ignorance

Since Elena Kunadt began her research on the history of the chemical herbicide atrazine in West German and American agriculture, she has been pursuing the question of whether political decisions taken on the use of this substance were solely based on sound knowledge. Her thesis is that decisions were also taken on the basis of ignorance and that this ignorance led to different assessments and thus differing political decisions. “In Germany, atrazine, which was particularly used in corn cultivation, was banned in 1991. It was subsequently banned in the entire EU in 2004. Its use is still permitted in the USA,” says Kunadt, who is writing her doctoral thesis on the history of atrazine at the Chair of the History of Technology.

EU directive based on ignorance

The ban on the herbicide atrazine is based on a directive of the European Community (now European Union) from 1980. This determined that the permitted levels of pesticide residues in drinking water may not exceed a concentration of 0.1 micrograms per liter. “But the ban was not based on knowledge that exceeding this concentration is harmful to humans or that atrazine itself is harmful to humans – as none of this has been sufficiently scientifically proven,” explains Kunadt. “The decisive factor was the agreement in the EU that herbicide residues should generally not be allowed in drinking water, precisely because too little or nothing is known about the harmful effects on humans.” Ignorance thus justified the EU directive and ultimately the ban in Germany.



Innocent until proven guilty

Quite a different approach in the USA: “Not knowing whether atrazine is harmful to humans did not lead to a ban but rather the decision that the substance may continue to be used as long as it is not proven to be harmful and that a threshold of 3.0 micrograms per liter, four times the permissible amount in the EU, is not exceeded in drinking water,” she says. Kunadt believes the reason for this very different decision in the USA is the different ways of dealing with a lack of knowledge: The EU acted on the principle of precaution and thus ascribed a potential danger to the substance. In the USA, the principle “innocent until proven guilty” directs the regulatory process, with the result that the substance is classified as safe until its impact on health can be directly proven.

The Americans introduced corn cultivation

Together with corn, atrazine was introduced to West German agriculture after 1945 with strong support from the Americans. Prior to this, essentially no corn was grown in Germany. And as a result, farmers had hardly any experience with this crop.

Oat now grew poorly

One problem with industrial corn cultivation is weed control. After the war, a lack of advancement in agricultural mechanization and a significant migration of the workforce from agriculture to industry meant that tearing weeds out either mechanically or by hand was extremely labor-intensive. Thus, as in the USA, the weeds were destroyed with chemical herbicides and finally with atrazine. Soon, however, West German farmers were confronted with the fact that, for example, oats grew poorly in fields where corn had previously been grown.

Research offers understanding of current debates

Weeds also developed resistance against the herbicide, “something which ultimately applies to every commonly used chemical herbicide,” says the researcher. “The pesticide industry and agricultural policy respond by repeatedly developing and permitting altered substances, which in turn leads to more resistance. Knowledge about resistance and residues and a lack of knowledge about environmental and health impacts have so far not led to a departure from this practice,” summarizes Kunadt. She finds this approach to knowledge and ignorance revealing, especially in order to understand current debates, for example on the pros and cons of glyphosate, but also to make decisions related to climate change. The history of atrazine shows, as if under a magnifying glass, how knowledge and ignorance give rise to failure to act or taking opposing action.

Further information

Elena Kunadt

Chair of History of Technology