Oregon cities say herbicide, used correctly, is safe


City of Salem employees use a small amount of the herbicide Roundup to address weeds in Salem parks. Like most Oregon cities, Oregon State University and even conservation groups, the City believes the controversial herbicide, when used in a science-based protocol, is safe.

Roundup is the most widely used weed killer in the world. Sold by Monsanto, it was first introduced in 1974; by 2016, Americans had applied 1.8 million tons of it to agricultural crops, residential landscapes, public parks and roadways. The herbicide’s key ingredient, glyphosate, is taken into plants through the leaves. Inside the plant, it prevents the formation of critical amino acids, causing the plant to die.



Roundup products are sold to the public in nearly every grocery and hardware store in Salem.

“Last year we used a total 8.92 gallons of concentrated glyphosate on some landscaped rights-of-way and parks,” says the City of Salem’s Kenny Larson, “but not every park or right-of-way.”

Larson notes, “The solution we use has the same percentage of active ingredients as what is available to general consumers. The concentration is also not as high as other formulations available to consumers.”

In Portland, Mark Ross of City of Portland says that Portland Parks and Recreation also uses Roundup. “Often people’s first reaction is that any herbicide or pesticide is too much,” Ross says. “We care deeply about the environment at Portland Parks and Recreation. That’s why we use science-based protocols. This means we do use Roundup and other herbicides in some situations.”

“Glyphosate is actually one of the least toxic options available,” says Nichole Linehan, who coordinates the Integrated Pest Management (IPM) plan for Portland parks. “That is why it is so widely used.”

Both the cities of Eugene and Corvallis also employ glyphosate to address targeted weeds. Jude Geist, Supervisor of Corvallis Parks and Recreation Department, says, “Most cities generally need to resort to some herbicides, including glyphosate, to manage weeds.” Geist reports that most Oregon cities, “including Salem, have a pretty extensive IPM plan that includes using other approaches – but they do have to resort to herbicides.”

IPM is a holistic system for reducing weeds using the least toxic methods (like hand-weeding) first and expanding up to and including herbicides. IPM employs a spectrum of techniques such as mechanical tools like mowers and cultural tools like growing native vegetation to shade out invasives. Oregon State University says IPM can help the environment by “keeping both pests and pesticides to a minimum.”

In Salem, Larson says, an IPM approach means, “When we do use glyphosate, we limit our application and target specific weeds and plants.”

The benefits of IPM practices are reinforced by the training that many park staffs receive from OSU, which supports the judicial use of glyphosate for weed control on city properties. OSU researchers instruct and certify many of the applicators of cities like Portland and Salem.

In Portland, City Parkand Recreation staff oversees more than 11,000 acres of public spaces and review each site on a case-by-case basis, exploring the least-toxic options first.

“The City of Portland only uses herbicides when there is no other option,” Ross says, “such as controlling ivy on acres and acres of trees. We know some think that any application is too much – but all of us who work in the Parks Department, we are all Oregonians and environmentalists ourselves. We use science-based practices as part of a detailed IPM plan.”

But Roundup is controversial. When used improperly it can cause eye damage and skin irritation and is dangerous to aquatic life.

Studies have also linked doses of it to health problems for people. A March 2018 study published in Environmental Health was the first to suggest that exposure to glyphosate can influence the long-term well being of children. It showed that women with high levels of glyphosate in their bodies, likely from eating food containing it, are more likely to have shorter pregnancies. This can lead to children with reduced brain development. Other studies have linked glyphosate to ADHD, Alzheimer’s disease, autism, heart disease, kidney disease and Parkinson’s disease.

The most alarming finding came in 2015, when the International Agency for Research on Cancer (IARC) of the World Health Organization concluded that glyphosate is “probably carcinogenic” and that there was strong evidence of an association between glyphosate exposures and non-Hodgkin lymphoma.

Many countries responded to the IARC announcement; Portugal now prohibits the use of glyphosate in all public spaces and Netherlands has banned all non-commercial use. This year EU countries such as Slovenia, Greece and Luxembourg signed a letter to the EU Commission calling for “an exit plan for glyphosate” while Germany’s government began the process of banning the chemical. 

California, in part because of the IARC conclusion, declared that Roundup was carcinogenic. While Roundup can continue to be sold in California, its label must describe it as toxic.

Given these troubling findings, why do cities like Portland, Salem, Eugene and Corvallis still use Roundup?

City and Parks Department staff in Oregon cities are universally aware of the research published on glyphosate. However they are generally educated by researchers from Oregon State who say that after thousands of studies, the balance of the scientific evidence suggests the chemical, when used wisely and properly – is safe.

Proponents say frightening studies about hazards usually don’t take into account the way the chemical may have entered the environment or was employed in the study. For example, agribusiness can overuse and inappropriately use Roundup, and doesn’t always follow safety protocols.

They also say too much of nearly any substance can be toxic. “Many people believe that some pesticides are ‘safe,’ while others are ‘dangerous,’” notes the City of Portland. “Actually, all chemicals, including all pesticides, have the potential to be hazardous. Even products that are considered low in toxicity, natural, or organic can be hazardous if someone or something comes in contact with enough of the substance.”

Finally, some park professionals express skepticism of some alarming studies and a news media that can be eager to spread fear. “I always ask, is the study conducted by a university?” asks Linehan. “Is it published in a reputable scientific journal? Can it be replicated? Because once glyphosate has dried on a plant leaf, it is no longer biologically active.”

At a recent training sponsored by OSU, Larson says, “researchers presented [Salem City staff] an analysis of studies where they concluded that there is no definitive proof that glyphosate is carcinogenic.”

The OSU researchers who taught Salem staff may have been referring to a 2015 reassessment by the European Food Safety Authority, which reviewed the troubling conclusions of the IARC. The new study found that glyphosate “is unlikely to pose a carcinogenic hazard to humans.” Jose Tarazona, head of EFSA’s Pesticides Unit, called the analysis “an exhaustive process – a full assessment that has taken into account a wealth of new studies and data.”

In 2017 the European Chemicals Agency, an agency of the European Union, also conducted a comprehensive data review. It concluded, “available scientific evidence did not meet the criteria” to classify glyphosate as a specific harm for “organ toxicity, or as a carcinogen, as a mutagen or for reproductive toxicity.”

Linehan says, “We never use the word, ‘safe,’ because that is a feeling. Toxicity is about risk and amount and rate. For example, glyphosate is unhealthy when it comes undiluted directly from the jug. But used correctly, it is one of the least toxic options for weed control – even compared with some organic products.” Even vinegar, “an acetic acid higher in toxicity than glyphosate if used at a higher rate,” Linehan says, can be hazardous in excess.

Michele Delepine of the Multnomah Soil and Water Conservation District considers herself an environmentalist “first and foremost” saying, “I got into this field to protect the environment.” Delepine says that her organization, whose work addresses invasive plants that threaten Oregon ecosystems by displacing natives, as well as the beneficial insects and wildlife that depend on natives – uses glyphosate in targeted situations.

“We do this in the context of improving our ecosystem health,” she says, “ and we use it as part of an IPM plan.”