Researchers sound alarm about common yard product after discovering potential link to cancer in dogs: 'Highly toxic'

Yahoo

11-06-2025

An animal welfare organization warned pet owners to be on their guard after multiple studies suggested that a lawn treatment raises the cancer risk for dogs.
According to the Natural Resources Defense Council, the culprit is "the most dangerous pesticide you've never heard of" — and it's still widely used.
In 2023, Humane World for Animals broke down how the herbicide 2,4-D raised the alarm among researchers after a 1991 study found that dogs whose owners used 2,4-D had up to a 200% higher risk of developing malignant lymphoma.
While a follow-up study (with links to the chemical industry) refuted the findings, another study in 2012 supported the first study's claims.
Dr. Lauren Trepanier, a professor of internal medicine at the University of Wisconsin-Madison School of Veterinary Medicine, suggested there may be one reason our furry friends could be particularly at risk compared with humans.
"We're not all going out and rolling on our lawns after we put herbicides on it," Trepanier said. On the other hand, dogs roll around, sniff, dig, and pick up debris with their mouths.
In 2016, Kristi Pullen, a staff scientist in NRDC's health program, warned in an article from the nonprofit that rising rates of 2,4-D use could "create a perfect storm of hazard and exposure coming together."
2,4-D can linger in the environment and harm biodiversity, contributing to food insecurity and economic losses. According to the Environmental Protection Agency, the chemical can be "highly toxic to fish and other aquatic life" relied upon by millions for food and income.
The International Agency for Research on Cancer also classifies 2,4-D as "possibly carcinogenic" to humans, per the Agency for Toxic Substances and Disease Registry. Several studies found that farm workers and professional herbicide applicators had an increased risk of certain cancers, including non-Hodgkin lymphoma, after high levels of exposure.
Despite the aforementioned findings, 2,4-D is still widely used to treat turf lawns, food crops, aquatic and forestry sites, and more, according to the EPA, which decided in 2004 and 2014 that it didn't have enough data to discontinue 2,4-D.
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Researchers are still investigating 2,4-D's connection to cancer, but NRDC senior scientist Jennifer Sass advised in 2016 that it is "better to take precautions to prevent possible cancers than to wait for more evidence." Dr. Barbara Hodges, program director of advocacy and outreach for the Humane Society Veterinary Medical Association, has a similar mindset.
"I advise my clients about the risks of cancer from these products and recommend that they not use lawn chemicals — for the sake of their pets and the human animals in their families, and also for the sake of wildlife species and the overall environment," Hodges, a practicing veterinarian, told Humane World for Animals.
Planting trap crops is one effective method of chemical-free pest control in gardens, while choosing cost-effective native plants reduces the need for pesticides overall. Trepanier also cautioned pet owners to be wary of walking their dogs in vibrant green parks during hot, dry seasons, as those parks likely used chemical herbicides and pesticides.
If you supplement your dog's diet with fruits and vegetables that aren't homegrown and guaranteed to be pesticide-free, also make sure to wash the produce first (while, of course, keeping in mind that some fruits and veggies, such as grapes and onions, aren't safe for your pets).
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