Roundup Weed Killer

Roundup is a popular weed killer containing glyphosate as its active ingredient. Initially registered in 1974 by Monsanto and now owned by Bayer, it’s extensively used in agricultural and residential settings.

Glyphosate is the most used herbicide in American agriculture according to the U.S. Environmental Protection Agency. Users apply approximately 280 million pounds of glyphosate annually to an average of 298 million acres of land. Users apply Roundup in various forms, like liquid concentrate and ready-to-use versions, using different methods like spraying and wiping.

Roundup is highly effective at managing weeds and is widely used in producing grains, nuts, fruits and vegetables. However, recent studies raise concerns about its potential health risks, particularly regarding Roundup’s links to cancer.

Glyphosate disrupts plant growth by inhibiting crucial enzymes. After application, it’s absorbed by plants and travels to the roots, shoots and leaves, ultimately killing them.

The enzymatic pathway targeted by glyphosate is not found in mammals, suggesting that the herbicide would not affect humans. However, the actual level of harm is still being questioned by many. 

It’s non-selective and doesn’t differentiate between weeds and other plants. Roundup kills most plants it contacts, requiring precise application. Some Roundup formulas affect plants within hours.

Monsanto engineered its Roundup Ready crops, which can resist Roundup, in 1996. Using Roundup Ready crops allows farmers to spray fields without fear of crop loss. The innovation revolutionized agriculture and immediately led to a boom in Roundup use.

In 2022, the EPA reaffirmed its claim that there are “no risks of concern to human health from current uses of glyphosate” when used in accordance with its current registration label. However, independent studies suggest a link to non-Hodgkin lymphoma with long-term exposure. Bayer disputes these claims, citing over 800 studies affirming Roundup’s safety.

In opposition to the EPA’s claims, the World Health Organization’s International Agency for Research on Cancer (IARC) classified glyphosate as “probably carcinogenic to humans” in 2015 based on evidence of DNA damage and tumor formation in animal studies. The study conducted by the IARC aimed to recognize potential causes of cancer, but it failed to account for the likelihood of exposure to doses of other carcinogens that may be encountered in the environment (like red meat, late-night work shifts and indoor emissions from burning wood), according to researchers at Penn State University.

A further study by the University of Washington published in Mutation Research found a 41% higher risk of non-Hodgkin lymphoma with heavy glyphosate exposure.

These differing conclusions highlight ongoing debates about Roundup’s safety. While the EPA reassures consumers, the IARC’s findings and independent research underscore the importance of continued scrutiny regarding the potential health risks associated with glyphosate and Roundup use.

Plaintiffs in Roundup lawsuits claim that manufacturers of the herbicide failed to properly label the product with cancer risk warnings.

In 2020, Bayer agreed to pay nearly $11 billion to settle most of these claims. However, thousands of active cases in the MDL and state courts across the U.S. still exist. As of March 2025, there were 4,414 Roundup lawsuits pending in multidistrict litigation in northern California.

Internal corporate communications at Monsanto suggest the company may have hidden the dangers of the herbicide. Individuals affected by Roundup exposure, particularly those diagnosed with non-Hodgkin lymphoma, can still file claims seeking compensation.

Despite Roundup’s potential link to cancer, the U.S. has not banned its use. The EPA says its review of available studies does not show that glyphosate has any human health “risks of concern” based on its current uses.

Bayer reformulated its residential Roundup products in 2023, replacing glyphosate as the active ingredient for residential versions sold in the U.S. Bayer CEO Werner Baumann emphasized that the move was not because of danger to users: “Let me be very clear that this is exclusively geared at managing litigation risk and not because of any safety concerns.”

However, glyphosate-based Roundup products are still available for agricultural and other large-scale uses.

If exposed to glyphosate from skin contact, inhalation or ingestion, promptly wash your skin and eyes and seek medical attention. Symptoms may include eye or skin irritation, respiratory discomfort, increased saliva and gastrointestinal issues like nausea and vomiting.

Fatalities have occurred in cases of intentional ingestion, though glyphosate generally exits the body unchanged (not metabolized) through urine and feces.

“We always recommend basic safety principles to our customers if they’re going to be working with glyphosate,” Chrissie Handley, lawn care specialist with Online Turf, told Drugwatch.

That means reading and following the recommended dosage and use instructions on the label. You should keep children and animals away during and after treatment to minimize their exposure. The Agency for Toxic Substances and Disease Registry (ATSDR) recommends waiting for 24 hours before allowing exposure.

Handley also recommends using personal protective equipment — PPE — to minimize your exposure.

“PPE would include protective clothing, eyewear and, if handling significantly concentrated glyphosate, you may want to wear a respirator [or] dust mask,” Handley said.

There are various Roundup alternatives for controlling weeds. Ways to control weeds include using mulch, herbicidal soap, corn gluten, manual removal or iron-based herbicides. Some organic herbicide brands can also help control weeds, but they are most effective when the weeds are newly sprouted.

Some home recipes for weed killer involve using vinegar, salt and dish soap. However, it is important to note that if this mixture is swallowed, it can be more toxic than glyphosate. Therefore, it should be kept away from children and pets.