The anti-biotech activist Gary Hirshberg, Stonyfield Farms CEO and recent White House nominee to a trade advisory committee, seems to enjoy highlighting bad news. Even when its boguswhen the news is in fact not bad at allhe manipulates it to serve his personal, ideological campaign against modern agriculture.

Thats what happened last week when the International Agency for Research on Cancer, an arm of the United Nations, claimed that the worlds most popular weed killer may cause cancer.

Hirshberg talked to every reporter who would listen, calling this one more reason to get behind his Just Label It initiative, which demands warning labels on packages of food with genetically modified ingredients.

Even if its in debate and even if its in dispute, said Hirshberg of the new cancer claim, at least give consumers the right to know.

You know what consumers have a right to know? Hirshberg is peddling a lie.

The problem started on March 20, when the IARC announced that glyphosate, the main element of the herbicide widely known as Roundup, is a probable human carcinogen.

Except that it isnt.

Glyphosate may be the most vetted technology ever developed. This makes sense, given its massive popularity. Around the world, farmers use it to grow healthy crops. Ive used it on my own farm in Iowa safely for almost 30 years. It is one of the tools we use to produce more food on less land, making it one of our best allies in the fight for food security and the battle against global hunger.

Every reputable agency that has studied glyphosate has reached the same conclusion: It does not threaten human health.

In January, the European Union released the results of its latest ongoing review, launched three years ago and conducted by the German Risk Agency: In epidemiological studies in humans, there was no evidence of carcinogenicity and there were no effects on fertility, reproduction, or development of neurotoxicity that might be attributed to glyphosate.

This is the scientific-research equivalent of what doctors call a clean bill of health.

Regulators in the United States agree. Glyphosate does not pose a cancer risk to humans, said the Environmental Protection Agency in 2013.

The IARC is not just out of step with every responsible group that has studied glyphosate. Its out of step with fellow researchers at the UNs World Health Organization, its parent organization.

Glyphosate is unlikely to pose a carcinogenic risk to humans, said the WHO in 2004. The next year, in a separate analysis, it determined that the presence of glyphosate in drinking water does not represent a hazard to human health.

So whats going on here? How could the IARC be so wrong?

Part of the answer is that we dont know: The IARC has published only a headline-grabbing statement, not a detailed report. Apparently the report will come later. For now, however, those of us who follow this debate feel like math teachers who have to give a student a poor mark not only for arriving at the wrong answer, but also for failing to show his work.

Heres what we do know: The IARC has not conducted any original research that reveals new information. Instead, it merely has looked over the mountains of existing data and come up with a vague assertion about an imagined risk, defying a well-established consensus.

We also know this: The IARC has a history of alarmism. Just a few years ago it touted the now-discredited claim that cell phones cause brain cancer.

Perhaps youve heard the suggestion that just about anything can cause cancer, if the dosage is high enough. This is true of ordinary food ingredients such as sugar. Its also true of the hormone estrogen. The problem is that the dosages must be implausibly highwell beyond ordinary usage and occurrence.

Studies consistently show that glyphosate is safe, even when exposure exceeds recommended levels by a factor of more than 100. Beyond that, who knows? But then again, who cares?

Gary Hirshberg does. He has an agendanot a scientific agenda of truth seeking, but rather a political agenda that aims to scare people. Sadly, it has nothing to do with human safety or scientific truth.

Bill Horan grows corn, soybeans and other grains with his brother on a family farm based in North Central Iowa. Bill volunteers as a board member and serves as Chairman for Truth About Trade & Technology.

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