Sarah Biren
Sarah Biren
March 25, 2024 ·  5 min read

This City’s Parks are Going Organic with Ban on Synthetic Weed Killers

Philadelphia has placed a ban on weed killers in parks and public spaces. The City Council’s unanimous vote passed the legislation to outlaw synthetic herbicides on city-owned land. The herbicides included in the ban have been linked to health issues like asthma, learning disabilities, and cancer.  

The Ban on Weed Killers 

Council member Cindy Bass sponsored this bill called the Healthy Outdoor Public Spaces Bill. It applies to parks, playgrounds, and trails that used to be treated with chemicals like glyphosate and 2, 4-D. Additionally, the Department of Parks and Recreation is responsible to track the use of pesticides and report them every year to the City Council. [1] 

Glyphosate has garnered much controversy in recent years when, in 2015, The World Health Organization’s International Agency for Research on Cancer called the pesticide “probably carcinogenic to humans”. [2] This caused an outcry against the chemical as people came forward to blame their cancer diagnoses on it. U.S. Environmental Protection Agency released a study in 2020 deeming glyphosate safe, not a carcinogen, when used properly.  

Nevertheless, public health advocates are wary. They believe people should be careful since it’s difficult to guarantee exposure levels. There’s a lot of concern for children, in particular, since their playing can put them at a high risk of being exposed. This is one of the main reasons for the ban on weed killers.

Children play close to the ground where pesticides settle. They put their hands in their mouths and breathe more rapidly than adults increasing inhalation exposures,” said Sarah Evans, the assistant professor of environmental medicine and public health at the Icahn School of Medicine at Mount Sinai.  

Resistance Against the Ban on Weed Killers

Although the legislation passed on November 26, the bill would slowly take effect throughout the next three years. Starting this July, pesticide use will be posted publicly by the Department of Parks and Recreation. Golf courses and athletic fields are the only areas that won’t be affected by this bill.  

In the meantime, the city is working to develop a plan for organic land management, including regular soil testing.  

The Department of Parks and Recreation did not show support for the ban on weed killers. The officials argue that the bill would make the land’s health and ecology harder to manage, especially because the legislations doesn’t come with enough funding. The department is already struggling because of COVID-19, with $12.5 million reduced from their budget. 

“The known alternatives to herbicides are far less effective and far more costly,” said Commissioner Kathryn Ott Lovell. “So our already-stretched capacity to manage invasive plants would be greatly reduced.” 

The bill does allow the department herbicide usage if the project is approved beforehand. However, the department considers this “solution” unhelpful since it won’t help their staff members with their regular duties. [3]

Still, many people stand behind the ban, like Emma Horst-Martz, an advocate for the Pennsylvania Public Interest Research Group.

Organic land management is a safe and effective alternative to spraying toxic chemicals in our parks and playgrounds,” she said. “This change is well worth it to ensure that children and adults alike can safely enjoy outdoor spaces in the city, especially during the COVID-19 pandemic.

The Research Behind the Week Killers 


Dow Chemical developed 2,4-D as a weed killer in the 1940s. Despite it’s widespread usage, researchers are beginning to discover that this chemical may be dangerous to people and the environment. These hazards may include hormonal disruption and cancer. 

The IARC called it “possibly carcinogenic to humans” in 2015. This statement evoked environmental and consumer groups to lobby against the use of 2,4-D. However, the link to cancer isn’t concrete because of how difficult it is to collect the data needed to confirm or disprove this. Even IARC gave their “possibly” statement because of “inadequate evidence in humans and limited evidence in experimental animals”. [4] 

However, according to Jennifer Sass, senior scientist at the Natural Resource Defense Council, “Those are all data and red flags, but there are so many reasons to get off this treadmill. Waiting for more confidence in the cancers means waiting for more farmers and pesticide applicators to get cancer, and I don’t think anyone wants to collect our data that way.” [5] 

In the meantime, the United States Environmental Protection Agency holds that products with 2,4-D are safe as long as they are used properly and that the weed killer overall has “low toxicity for humans”. Nevertheless, they continue to evaluate the chemical. [6] 


Glyphosate was invented by Henri Martin, a Swiss chemist, in 1950. Two decades later, a chemist named John E. Franz improved the formula to become a plant-killer. Monsanto patented glyphosate in 1974 and began selling it as a herbicide under the name Roundup. Although it’s sprayed on public and private lawns, people became concerned about its safety. [7] 

It became infamous when the IARC deemed it “probably carcinogenic to humans” based on animal tests. The EPA maintains its safety because of multiple studies on the potential cancer-causing effects, including a 2017 study with a large group of agricultural works that found no connection between glyphosate and cancer. [8] 

However, there are conflicting studies available, like the 2019 review that found workers exposed to high amounts of glyphosate had a 41% higher risk of developing Non-Hodgkin lymphoma. [9] Still, more research is needed to prove this link.  

At this point, it seems that the potential hazard of this herbicide comes from inhaling it as opposed to eating food sprayed with it. The possible negative effects are what brought on the ban on weed killers in Philadelphia. 


  1. Philly parks are going organic with ban on synthetic weed-killers.” WHYY. Taylor Allen. December 3, 2020.
  2. IARC Monograph on Glyphosate.”  International Agency for Research on Cancer
  3. Environmental group says cancer-causing pesticides lurking in soil at Philly parks.” ABC. Chad Pradelli. August 19, 2020.
  4.  “WHO unit finds 2,4-D herbicide ‘possibly’ causes cancer in humans.” Reuters. Carey Gillam. June 23, 2015. 
  5. “Last year it was dicamba, this year it’s 2,4-D.” AP News. Johnathan Hettinger. March 30, 2019.
  6. 2,4-D” EPA
  7. What is glyphosate?” Live Science. Jen Monnier. September 18, 2020.
  8. Glyphosate Use and Cancer Incidence in the Agricultural Health Study.” Journal of the National Cancer Institute. Gabriella Andreotti. November 9, 2017.
  9. Pesticide use and risk of non-Hodgkin lymphoid malignancies in agricultural cohorts from France, Norway and the USA: a pooled analysis from the AGRICOH consortium.” IEA. Marria E. Leon. March 18, 2019.