Geoff Bennett:

As reported earlier, in a 7-2 ruling today, the U.S. Supreme Court sided with the manufacturer of the weed killer Roundup. The decision overturns a jury award to a man who said more than two decades of exposure to Roundup caused him to develop a type of blood cancer. The ruling is expected to block thousands of similar lawsuits across the country.

Joining us now is Dr. Chadi Nabhan. He's a medical oncologist and the author of "Toxic Exposure: The True Story Behind the Monsanto Trials and the Search for Justice." He also served as a key expert witness in three of the first Monsanto trials.

Thank you for being with us.

Dr. Chadi Nabhan:

Thank you, Geoff, for having me.

Geoff Bennett:

So Roundup is one of the most widely used herbicides in the country, used on more than 300 million acres of U.S. farmland and sold since the 1970s. We can walk into a home improvement store right now and buy a bottle.

What does the science tell us about the potential health risks?

Dr. Chadi Nabhan:

We have learned a lot about Roundup and its active ingredient, glyphosate, over the years. Mainly, it's linked to carcinogenicity and the ability to cause cancer and specifically non-Hodgkin's lymphoma.

The IARC, the International Association on Research on Cancer, in 2015, labeled glyphosate, the main ingredient of Roundup, as a probable human carcinogen based on published data, peer-reviewed literature, based on animal studies, toxicology studies, as well as epidemiological studies.

So we know today, in 2026, way more than what we knew back then in the '70s and '80s, when Roundup came to market. But the most important part that we know is, it's linked to carcinogenicity and specifically non-Hodgkin's lymphoma, which is the blood cancer that you were referring to earlier.

Geoff Bennett:

So, the EPA, when it says that Roundup does not cause cancer if used properly, and they didn't require Monsanto, which was later acquired by Bayer, to have a warning label, what are they basing that on?

Dr. Chadi Nabhan:

I think it's important to look at the entire picture.

The EPA usually looks at the evidence that is available to them at the time, and often that evidence is presented to them and supplied by the manufacturer of the herbicide or the pesticide. And, of course, the evidence changes. The evidence evolves. Science changes and science evolves.

We know today way more things than -- when we knew many years back. So the EPA really relies on the evidence that was presented to them. But one of the most important things to know that -- just to give you an example, one of the papers that the EPA relied on was retracted just recently, several months ago.

It was a paper that was authored by Williams and colleagues, and that paper was retracted because of ethical concerns and research misconduct. This is the paper that continues to be cited by everyone that says glyphosate is safe and Roundup is safe.

So if the paper that everybody says is a good paper and this is something that's safe gets retracted because we don't know the integrity of it, and the EPA relied on it at the time, then there is a problem.

Why was the paper retracted? Because of the litigation trials, because of what surfaced in courts, because of these lawsuits that actually brought this paper to light.

Geoff Bennett:

In a statement to the "News Hour" after today's ruling, Bayer said this in part: "The U.S. Supreme Court decision is good for science, farmers, and industries that depend on regulatory clarity for innovation. It should help significantly contain the Roundup litigation after nearly a decade of legal battles."

So what are the larger implications here?

Dr. Chadi Nabhan:

I think there's a legal aspect of this, which I cannot comment on because I don't have the legal expertise.

But from a scientific and a medical perspective, as someone who has treated and cared for hundreds on hundreds of patients with lymphoma, it is important for us to identify and know the causes of this disease, if we can. Many times, we can't. Many times, a patient has a disease and they ask, why do I have it? And we don't have an answer.

But if we're able to identify a cause, and if there is a possibility that a compound like this is causing cancer and is hurting people, it is our obligation to not have it available to the general public.

And, look, I mean, again, you -- we all know that, 50, 60 years ago, we thought tobacco was safe, didn't we? We actually had doctors advertise for smoking. We had people smoke in the hospitals. There are pictures of this online.

Well, we know today that it's not. So it's OK to admit that we know today more than we knew before. But I believe it's a nihilistic approach to ignore the evidence and to say, well, it's very safe, do whatever you want with it, and nothing to worry about. It's just not true.

Geoff Bennett:

Dr. Chadi Nabhan, thanks again for joining us. We appreciate it.

Dr. Chadi Nabhan:

Thank you for having me.