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Why the Addition of a Warning Label to Roundup Matters

Nathan Donley, a staff scientist with the Center for Biological Diversity, discusses the harmful side effects of the glyphosate.
(Photo: Mike Mozart/Flickr)

(Photo: Mike Mozart/Flickr)

Last week, the California Environmental Protection Agency (CalEPA) announced plans to label glyphosate—commonly known as the primary ingredient in the herbicide Roundup—as a cancer-causing chemical.

Proposition 65, voted into California law in 1986, requires the state to publish a list of chemicals linked to either cancer or birth defects. Any business putting consumers in contact with these chemicals is required to warn its customers about their potential hazards, either in the form of public notice, a workplace posting, or a label on the product. Environmentalists are rejoicing the state's announcement to label glyphosate as a carcinogen, hailing as it a key step toward eventually placing federal restrictions on the chemical.

We can thank Monsanto, the agrochemical and biotech powerhouse famously vilified in the 2008 documentary Food, Inc. for all those "Roundup Ready" corn and soy crops genetically modified to survive normally fatal doses of the glyphosate. Farmers, in effect, can plant Monsanto’s herbicide-tolerant crops and spray their entire fields with glyphosate to kill all other weeds. It's no wonder, then, that Roundup is the most commonly used glyphosate-based herbicide in the entire United States. Between 1990 and 2012, use of glyphosate on crops nationwide increased from 10 million pounds to more than 280 million pounds of the herbicide.

Glyphosate has been linked to a host of human health and environmental defects. In March, the International Agency for Research on Cancer announced that glyphosate, among several other pesticides, is a probable carcinogen. Additional research has found that rats exposed even to low doses of Roundup can sustain liver and kidney damage.

The herbicide has also devastated Monarch butterfly populations. Monarchs feed solely on milkweed, which, thanks to products like Roundup, has been wiped out throughout the Midwest. According to the Center for Biological Diversity, butterfly numbers have declined by more than 80 percent in the last two decades. Such steep population drops prompted the Center to file a legal petition last year with the U.S. Fish and Wildlife Service seeking protection under the Endangered Species Act. USFWS is expected to announce by the end of the year whether the proposal will be accepted, rejected, or added to the candidate waiting list, says Nathan Donley, a staff scientist with the Center for Biological Diversity.

We had the chance to speak with Donley about why California's intent to label glyphosate as a human carcinogen might help save monarch butterflies nationwide, and why the herbicide has been so controversial since it first hit the market.


How does glyphosate affect wildlife?

Basically the entire central part of our country is just being doused in glyphosate. It's killing all plant life except for agricultural crops. The milkweed plant is the sole host plant of the Monarch caterpillar; the Monarch is completely reliant on milkweed for survival as a species. Without that plant, we've seen Monarch populations decline 80 to 90 percent in the last 10 to 15 years. This once abundant species is now pretty rare.

Nathan Donley. (Photo: Elise Wong)

Nathan Donley. (Photo: Elise Wong)

The fact that an entire species can go from abundant to rare in such a short period of time is frightening. It really shows how powerful this chemical is at degrading habitat.

Why is the CalEPA's announcement so important?

If they decide to list this chemical [under Proposition 65] and it survives the inevitable legal challenges, I think it's possible that every bottle of Roundup or glyphosate formulation sold in the state of California would have to be labeled as known to the state of California to cause cancer.

It would be a huge deterrent for the purchase of this product, at least in that state. I think Monsanto has created this false narrative that glyphosate is safe. That position clearly can't be maintained anymore. It decreases, in my view, the credibility of Monsanto, and I think it will probably be a precursor for hopefully federal action, at least federal acknowledgment that glyphosate does cause cancer.

Glyphosate residue has been found on up to 90 percent of the country's soybean crop. Why is this worrisome?

The unprecedented amounts of glyphosate that are being applied—right now I think the latest figures are from 2012, and it's around 280 million pounds used in the U.S.—that number just boggles your mind. It's just so, so widespread. It's infiltrating entire ecosystems. Animals and wildlife are going to be foraging for food around crops and being exposed. They're going to be drinking water that can have detectable levels of glyphosate. This glyphosate exposure is also acting in concert with thousands of other artificial toxins that are in our environment, so looking at glyphosate exposure as a single toxin is really not getting the entire picture. You have to look at it in the entire context of everything else that's being put into the environment.

Why is glyphosate so popular nationwide?

Somewhere around 90 percent of all the soy grown in this country is glyphosate-tolerant, and corn, I think, is just below that, around 88 or 89 percent. We're looking at almost entire species of crops that have this genetic trait. The wide adoption of these crops has caused people who farm to use increasing amounts of this pesticide.

In 1990, 10 million pounds of glyphosate were used each year on crops in the U.S. In 2012, that number rose to around 280 million—that's a 2,700-percent increase in usage since Roundup-ready crops have been in widespread use. This chemical really is so widespread that no matter where you live, or what you eat, it's nearly impossible not to have exposure during your lifetime.