Glyphosphate Questions & Answers

Several Master Gardeners and members of the general public have called on Extension to provide guidance on glyphosphate use. Kaci Buhl (OSU Statewide Pesticide Safety Education) and Chip Bubl (OSU Extension Horticulture/General Agriculture) collaborated to develop a list of Q&As that might be helpful to you and your MGs, when you receive glyphosphate-related questions. I have copied and pasted their document, below.

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Glyphosate Questions & Answers

Kaci Buhl, Chip Bubl

Oregon State University Extension

What is glyphosate?

It’s a weed-killing chemical found in Roundup and many other weed killers. Like other herbicides, it is usually combined with one or many other ingredients to make the final product.

Does OSU have an official position for or against using glyphosate?

No. It is our mission to educate, not to legislate. We’re happy to answer questions and help find solutions using any legal, effective methods, while considering the risks.

Does glyphosate cause cancer in humans?

Maybe, at high enough doses. If it caused cancer at realistic exposure levels from using weed-killers, then farmers and other applicators would be the first to show this effect. The largest study ever published, looking at farmers and other applicators, found no association between glyphosate and solid tumors, including Non-Hodgkins Lymphoma (NHL).

That study found a potential association between glyphosate exposure and a certain type of blood cancer that was not statistically significant. Another study suggested that using fertilizers could account for this risk.

Why do regulators disagree about this?

They don’t. Not really.

The International Agency for Research on Cancer (IARC), an arm of the World Health Organization (WHO), determined in 2015 that glyphosate is a probable human carcinogen. That determination was surprising to many. IARC responded to critics by clarifying its intent – to identify potential hazards. They asked, “Can it cause cancer under any circumstances?” They group hazards based on the strength of evidence, not the potency of the carcinogen(s). They defer to national and international bodies to take the next step, which is risk-assessment. Risk assessment is based on expected levels of exposure and background cancer rates.

Many governments have published risk assessments about glyphosate, finding it is unlikely to cause cancer in humans when used according to the label directions as required.

To put the IARC determination in context, they put the following items in the same category as glyphosate, Group 2A “Probable human carcinogens.”

  • Red meat
  • Indoor emissions from burning wood
  • High-temperature frying
  • Late-night work shifts

The following items were placed in a stronger-evidence category, “Known human carcinogens.”

  • Processed meats
  • All alcoholic beverages
  • Sunlight
  • Engine exhaust
  • Outdoor air pollution

The work of hazard identification is important, but it’s only the first step in understanding risk.

What about the other ingredients in Roundup?

Researchers reviewed the scientific literature on glyphosate, its major metabolite AMPA, formulated Roundup® products manufactured by Monsanto, and the surfactant POEA. They concluded that none of the components caused cancer. However, POEA can be harmful to a variety of aquatic wildlife (i.e. minnows, frogs, micro-organisms).

It can be difficult to determine the risks associated with other ingredients in pesticide formulations, including Roundup. This is because manufacturers are not currently required to identify “other ingredients” on product labels.

How have the courts ruled?

Courts have ruled in different ways on this issue. A California jury found Monsanto liable in August 2018 for causing a man’s cancer. The man used glyphosate weed-killers for years. The case has been appealed. In contrast, a federal judge in California ruled in June 2018 against the state’s case for placing warning labels on containers of glyphosate under Proposition 65. It would have required warnings about the potential for glyphosate to cause cancer. The judge cited a “heavy weight of evidence” that the risk was very low. The courts will likely evaluate more cases in the future.

Are foods with glyphosate residue safe to eat?

A tiny amount of glyphosate is not likely to cause harm, even if we eat those foods daily. There are residue limits for glyphosate on many fruits, vegetables, corn, grains, milk, and eggs. The FDA monitors the level of glyphosate on foods in the marketplace. So far, they have not found foods with too much residue, based on risk assessments. The dose makes the poison.

How can I reduce my risk?

If you choose to avoid glyphosate exposure altogether, seek out organic foods with the official logo from USDA. Glyphosate is not allowed to be used in organic settings. Use alternative methods of weed control. Talk with your local master gardeners about what’s working for them..

If you choose to use glyphosate weed-killers, make sure to follow the product label carefully. The label is the law. While glyphosate is poorly absorbed through the skin, some parts of the body are more absorptive than others. Minimize your exposure, and keep others away until sprays have dried. Talk with your neighbors about any concerns they might have, and take steps to accommodate their needs.

October 2018 Update

Updates from the Statewide Master Gardener Program

  1. MG Instructor Database: for those of you searching for instructors for your 2019 MG classes, please remember that the list of MG instructors is annually updated, and housed in the ‘Master Gardener Program’ on Box. If you need access to this folder, please let me know. Specifically, the Excel file with the list of MG Instructors is in the sub-folder called ‘MG Basic Training Resources’, which can be accessed via https://oregonstate.box.com/s/alop5gv86az1q5zjscomgghds1v4y2mn
  2. MG Core Courses: Signe Danler recently sent out a information on how to access online Master Gardener modules, to supplement your in-person MG trainings. The required classes for MG training (Oregon MG Program, Botany Basics, Understanding Pesticides) are FREE for use. Other modules are available on a sliding scale ($50-$150 per module). If the sliding scale is out of your range, but you are interested in using an online module, please let us know. We charge a modest price to help cover basic program costs, but want to be flexible for counties without resources.
  3. MG Re-certification Stickers: I have 2019 Re-certification Stickers to send out for veteran MGs who have completed at least 10 hours of continuing education and 20 hours of approved volunteer service. If you have not already done so, please let Gail know (via email) how many stickers you need for your Master Gardener Program. They will go out in next week’s mail.
  4. Best Management Practices for MG Plant Sales: I have received feedback on our first draft from our task force. My goal is to synthesize all comments into a revised draft, by the end of this week (October 12th).
  5. 2018 CHAP Update: The 2018 Consumer Hort Advisory Panel came up with three recommendations to make annual MG trainings more fun, interactive, and accessible. These recommendations were to: a) move towards active learning in MG training classes; b) consider ways to keep costs low for MG trainings (scholarships, payment plans); c) lower the minimum number of required volunteer service hours for new MG trainees, to 55 or fewer hours. You can see the full description of recommendations on the hypertext entitled CHAP DRAFT Recommendations April 2018 on this page. At our working group meeting in July, recommendations 1 and 2 were adopted. Recommendation #3 received majority support, but there was still a lot of concern related to this recommendation. We are thus tabling this third recommendation, for the moment.
  6. Working Group Innovation Grant Funded:  Several Home Hort working group members advanced a proposal for a two-day retreat, to carefully consider what changes are needed to build a more inclusive EMG Program, but also how to implement change. Our Innovation Proposal for the Home Hort Working Group was funded!!! We are targeting May or June for the actual two-day retreat. Keep an eye out for the first step in this effort ~ a survey of MG coordinators.
  7. Fall OMGA Newsletter: The fall issue of the Gardener’s Pen Newsletter has been published and posted online. Please make sure that your Master Gardener volunteers have access to this statewide MG newsletter.
  8. 2019 International Master Gardener Conference (IMGC): If you will be attending the 2019 IMGC (June 16-21, 2019 in Pennsylvania), the room block is now open for reservations. Registration is not yet open, but the full slate of speakers and tours has been posted.
  9. Professional Development Opportunity, “Achieving the Extension Mission through Volunteers“: an instructor-led, online course offered by the University of Minnesota. This course has received positive reviews from other Extension Master Gardener coordinators. The cost is reasonable ($250), but the timing coincides with Oregon’s Master Gardener training. Topics include ‘Identifying and Recruiting Volunteers’, ‘Selecting and Matching Volunteers’, ‘Supporting Volunteers’, and ‘Communicating Public Value’. If you are interested in taking this course, but cost is an issue, please let Gail know.