• MD-DE Forage Council

The Dirt on RoundUp

by Matt Morris, Agriculture Educator, Frederick County


Recently, someone I know had a bag of wood chips for their grill and right on the bag it said, “This product is known to the State of California to cause cancer.” It’s a good thing we live in Maryland and not California or else we’d have been in trouble! In all seriousness, that bag of wood chips reminded me of a similar situation that is all over the radio and TV and that is the glyphosate/cancer relationship. I am by no means a health professional, but I do know a little bit about the reason this has come to be national news so I will try to outline that below.


First let me give some background on glyphosate. Glyphosate, which is the main ingredient in the herbicide RoundUp® (and countless generic versions) was first commercialized in the 1970’s as a broad-spectrum herbicide, meaning it works on both grasses and broadleaf plants. The appeal was that it worked on many weeds, but had no residual activity in the soil as it was immediately decomposed in the soil into carbon dioxide, ammonia, and phosphoric acid by soil bacteria. It was one of the products that paved the way for no-till crop production. Yet, it did not gain widespread popularity until the advent of crops that were tolerant of its spray. I personally think this is when the disdain for glyphosate began as it was associated with “GMO” crops.


Fast forward to 2015 and The International Agency for Research on Cancer (IARC), a division of the World Health Organization, determined in 2015 that glyphosate is a probable human carcinogen. This lead to the August 2018 ruling by a California court that Monsanto was responsible for a worker’s cancer. My concern is that a jury came to this conclusion, not a group of scientists. The reason the IARC came to that conclusion is in the question they asked: Can glyphosate cause cancer under any circumstance? This probable carcinogen determination is what lead to the wave of lawsuits against Monsanto, the developer of RoundUp®. What they did not determine is the actual cancer risk a user of glyphosate may be exposed to. In essence, what is the risk of cancer from glyphosate to the user when used according to the label and under normal circumstances? That determination would normally be made through risk assessment studies, of which there are many. The EPA and the European Food Safety Authority have both conducted risk assessments on glyphosate and found it unlikely to cause cancer in humans when used according to the label.


But let’s go back to the probable human carcinogen finding from The IARC. There are many things that fall also into that probable category: fried food, red meat (which must be a mistake), and late night work shifts. Even worse are the “known human carcinogens”: alcoholic beverages, sunlight, Chinese style salted fish, and air pollution among many others. I think what that is telling us is we should be drinking (moderately) in the shade! In all seriousness this means that there are lots of things that can cause cancer in high enough doses. We all know that sunlight can give us cancer so we take steps to minimize our risk like wearing clothes or putting on sunscreen. The same should be done with glyphosate. Use it in accordance with the label and science says your risk of cancer is extremely low. My other question is this: why have many of the known human carcinogens we use in everyday life (gasoline anyone?) not received the same treatment as glyphosate? Is it because there is no unifying villain like Monsanto in the alcohol or salted fish industries for people to rally against?


Decades of science and studies have tried to find the definitive link between cancer and glyphosate, but have yet to yield any. If they do, I will be the first one to say something must be done. However, so far science has said the opposite. That is why I believe the proper use of this important chemical is not something we should spend a tremendous amount of time worrying about.

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