Glyphosate aka Roundup fact or fiction?

Published 9:45 am Sunday, September 3, 2023

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I did a class for the Cypress Landing community a few weeks back and one of the questions was about Roundup or herbicides that contain the active ingredient glyphosate. I have taken several calls over the last few years from folks telling me they are afraid of Round-up (or other products with the active ingredient glyphosate). A while back there was a talk offered for advanced education of NC State Extension Master GardenerSM volunteers led by Dr. Joe Neal, Professor of Weed Science and Extension Specialist. He put a talk together titled: Glyphosate: Can we separate fact and fiction? And, how do we control weeds without it?

Dr. Neal did an amazing job explaining the facts and fiction surrounding the product. He discussed the science behind the World Health Organization’s (WHO) International Agency for Research on Cancer finding that glyphosate is “probably carcinogenic to humans” while another division of WHO, the Joint FAO/WHO Meeting on Pesticide Residues concluded that “glyphosate is unlikely to pose a carcinogenic risk to humans…”. In fact, no other major national regulatory agency in the world classifies glyphosate as a probable carcinogen. He went into detail about how New Zealand’s Ministry for Primary Industry took this a step further in showing the difference between a hazard assessment and a risk assessment. The other parts of the discussion concerned the food levels of glyphosate, risk assessment, personal protective equipment, pesticide safety classification for conventional and organic pesticides, and alternatives that are available in place of glyphosate.

A hazard assessment tests the possibility of danger. Picture a busy street in a city that never stops. Would you cross the street with cars coming? There is a good chance you will get hurt! The cars are a hazard, Does this mean that we should outlaw all cars? Now would you cross if the light indicates it is safe to cross? That light telling you to go is your personal protection equipment (PPE). This minimizes the hazard. Risk on the other hand is a factor of hazard times exposure. We have the hazard but what is the likely exposure to the hazard if you are using your PPE and following the label for the product? By the way, fun fact, the LD50 (lethal dose, given all at once, in 50% of test subjects, expressed in mg/kg of body weight) of glyphosate is 5600 mg/kg, the LD50 for caffeine is 200 mg/kg. I hope you aren’t reading this while drinking your morning dose of caffeine!

Inevitably, these discussions then turn towards residue in foods. Is there glyphosate residue in our foods? Yes. Is it dangerous and is it going to cause cancer in all of us? Studies are done on this subject as well. The Environmental Protection Agency calls it the NOAEL – No Observed Adverse Effect Level. They find this level through scientific study and then add a 100-fold safety factor to it to define the level at which chronic exposure over a prolonged period may result in adverse effects. Using this factor, a 175-pound person would have to consume 2,285,714 carrots per day for a period of two years to reach the threshold. Don’t eat carrots, how about 3,389,831 bananas per day for two years? Not a fruit or vegetable fan? How about 12,454, 12-ounce beers per day for a period of two years?

Now, I say all of this to get to the nuts and bolts of this thing, no matter what the chemical, we need to be using it correctly. Are there hazards? Absolutely. Are there risks? You bet. How do we minimize our exposure and therefore lessen the risk of the hazards? Use your PPE and read the chemical’s label entirely. Wear waterproof gloves and shoes with long pants. Wash your PPE according to instructions. This really goes back to common sense; does it matter if a gun is loaded or not? Always treat a gun as if it was loaded, always treat one of these chemicals as if it were a loaded gun.

Do you want to go organic? OMRI approved herbicide chemicals carry warning labels too. You must still read the label and take the proper precautions using correct PPE and application procedures. NC State has resources for you too including a factsheet for glyphosate alternatives (

You can get more information on glyphosate and other chemicals by visiting the NCSU Weed Management Portal at This site is a wealth of information that contains factsheets on herbicides, damage factsheets, weed ID, and management resources. Get the facts and make an informed decision about what you want to do and how you want to do it.

NC State Extension provides unbiased, research-based, University information to you the consumer or producer. If you have not visited your local Cooperative Extension Center, you may be pleasantly surprised by all the information, workshops, and programming we offer. We will have a fall veggie class coming up on September 9 (please register by following this link: and veggie sale on Saturday September 16, call our office or look on the Beaufort County Master Gardeners’ Facebook page for more information. If you are interested in the Extension Master GardenerSM Volunteer (EMGV’s) program training, now is the time to call our office or visit the website ( for more information. We will be having a training that will begin in September. We will meet on Tuesdays at the Beaufort County Center from 9:00-12:00 beginning September 19. If you are interested, please send in your application!

If you are having an issue in your home garden or landscape, send your questions to Gene Fox, Consumer Horticulture Agent with the North Carolina Cooperative Extension Service, please email Gene at or call at (252)946-0111. Learn more on Facebook at the Blacklands Area Horticulture page or visit the Extension Office located at 155 Airport Road in Washington, NC.