DW: The European Chemicals Agency (ECHA) has said the weed killer glyphosate does not cause cancer. However, it kept the classification as a "substance causing serious eye damage and being toxic to aquatic life with long-lasting effects." Is that not enough to ban the chemical?

Karl Bär: If it was up to me to decide, the severe effects that glyphosate has on biodiversity would be enough to ban the chemical. But I doubt this is enough for the European Commission, which is very much in favor of using glyphosate.

And it will most probably use the ECHA's ruling that glyphosate is not causing cancer as a chance to again suggest to the member states that they should not ban glyphosate.

There have been reports of higher cancer rates in areas where glyphosate has been used. What kind of data did the European Chemicals Agency use to come to the conclusion that it doesn't cause cancer?

They are using the same data most probably that the European Food Safety Authority used already - collected by the German Federal Institute for Risk Assessment (BfR), which is in Berlin. And they are basically using data that they got from those companies producing glyphosate, which is a flaw in the system of chemical registration and classification in Europe.

Because it's essentially the companies providing the data?

The idea behind that - which is what the agencies say is good about it - is that those companies have to pay for the risk assessment which the agencies do. But they are also choosing the scientists and the questions - which makes it problematic. There is very little value given to independent data in those processes.

There's a huge problem with that. As long as we do not solve it, we will constantly have a dispute on whether the data is valid or not.

Do you agree with those findings - that glyphosate does not cause cancer?

I'm not a medical specialist, but I would not trust the data that they have and I would not agree that this is right.

There has been a ruling by the International Agency on Cancer Research in Lyon, a United Nations body, which said that it is most probably cancerogenic for humans.

And they have based their ruling on public and peer-reviewed studies only, which makes their result more trustable for me.

Glyphosate is designed to kill every plant that has not been genetically modified to be able to cope with the chemical. What does that mean for biodiversity in the long run?

Glyphosate is very effective for the use it's designed for. And that has a lot of negative consequences on biodiversity, because it kills everything.

So if there is nothing left but corn, you will have very few insects, you will have very few birds, you'll have very few mammals that live on insects and birds. Using huge amounts of very effective weed killer, you will destroy the whole ecosystem.

How long will the chemical remain in soil and water?

That is not a big problem with glyphosate - there are bacteria in the soil that destroy glyphosate and tear it apart into other components that then are slowly also [broken down]. So glyphosate is usually not found in groundwater aquifers, because it dissolves in the soil.

But this is only true as long as those bacteria are present in soil. So if you use glyphosate in, let's say, parks in your city to clean places where you walk or stand - weeds on stone [pavements] - you will not have those bacteria. Then glyphosate can go into the groundwater, which is why usually those uses are forbidden.

Because it's more or less sealed pavement and if you were to spray it to get rid of weeds, you don't have the soil with those bacteria that you were just talking about?

Yes - that is usually forbidden, but it's nevertheless done a lot by [individuals] who do not know it's forbidden.

There's a use of about 60 tons of the component in Germany by [individuals] every year. That is about one percent of the total use, but still has the most effects on groundwater.

Glyphosate has been found in people's urine, in food, even in beer - why is that not enough to stop using it?

Well, that would be good enough to stop using it if there was any official body within the European Union saying this is either cancerogenic or it is an endocrine-disrupting chemical [a chemical that either mimics or blocks hormones and disrupts the body's normal functions], or it is causing birth defects. There are a few cut-off criteria. As long as no official institution claims that glyphosate is within those cut-off criteria, they will not act.

Some weeds have already become resistant to glyphosate - doesn't that mean it's obsolete anyway now, since it no longer does what it was supposed to do?

What you can do as a farmer if you have a weed that is resistant to glyphosate is to use both glyphosate and other components like 2,4-D [2,4-Dichlorophenoxyacetic acid], which was used in Agent Orange in the 70s.

If you combine those with glyphosate, you'll kill everything and you'll kill those weeds that have grown resistant to glyphosate with the other component. Until you find a weed that is resistant to a multitude of different components - and it will become more and more complicated.

Glyphosate is considered extremely dangerous when it's combined with certain substances like POE tallow amine. Why is that?

Tallow amines are used to make glyphosate access the plants more easily. So the plants take up glyphosate through their green leaves and the tallow amines make glyphosate spread on the leaves better. And that has been used a lot with glyphosate because it increases its efficiency.

But those tallow amines have been found to cause a lot of human health problems, and they are banned in many European states. However, they are still used a lot in South America.

What do you think will happen next after the decision by the European Chemical Agency?

Most probably the European Commission - based on both the European Food Safety Authority and the European Chemical Agency rulings - will suggest to the member states that they renew the registration of glyphosate for something between 10 and 15 years.

And then the member states have a vote on that.

The member states vote with a qualified majority. So if there is no qualified majority to either ban or renew the registration of glyphosate, the Commission has the possibility to do whatever it wants to do. And the Commission will most probably say the registration is renewed.

The Commission last year was hesitant to do that, because they do not want to go through all the public "shaming and blaming" for renewing glyphosate again and again. They want the member states to take more of the responsibility. And that is one reason why they have again and again put the issue on the agenda of yet another meeting. And it could happen that this game is going on for a while.

But I'm very sure that the Commission now feels more safe to suggest another, very long renewal of authorization for glyphosate.

But you said the member states are the ones voting on it, so if a majority of member states were to say we want glyphosate banned then this would be the decision?

Yes, that is a very good part of this European process, because the people voting on this final decision are members of the governments of the member states. So they are elected politicians; they are responsible in public. They are responsible in elections. And we have a possibility to put pressure on them.

Karl Bär is an expert on agricultural policy and trade with the Munich Environment Institute.