This story was updated on June 3rd after receiving information from New York City’s Department of Parks and Recreation.


A herbicide used to control weeds in New York City’s parks may be linked to cancer in humans. Roundup, which is the liquid herbicide most heavily used by the city’s Parks Department, has again become the subject of controversy.

Roundup was sprayed in New York City parks over 1,300 times in 2013, according to a Health Department report.

Questions about Roundup’s connection to cancer have been raised before but a new analysis by the International Agency for Research on Cancer has classified glyphosate, the active ingredient in Roundup, as “probably carcinogenic to humans.”

That analysis needs to be put in a broader context, however, argues a recent article in the New York TimesTimes reporter Andrew Pollack writes that the IARC has examined substances like glyphosate through a “very narrow” lens- that being whether they “might cause cancer under some circumstances, even if those circumstances are unlikely to occur.”

The agency classifies alcoholic beverages as human carcinogens, along with tobacco, arsenic and asbestos, says Pollack. Even activities like working the night shift (because of major sleep disruption) or being a hairdresser (because of repeated exposure to chemical dyes) are classified as “probably” cancer-causing, he reports.

A push to limit use of synthetic pesticides in NYC’s parks

Despite -or because of- this lack of certainty, City Council Member Ben Kallos of Manhattan has introduced legislation that limits the use of traditional pesticides in New York City’s parks.

Citing what he described as “unnecessary, toxic pesticide use,” Kallos said in a statement that “all families should be able to enjoy our city parks and resources without having to worry about what chemicals are being used.”

The Department of Parks and Recreation provided the following statement in response to our questions about its use of glyphosate, the new analysis showing a possible connection to cancer, and Council Member Kallos’ proposed legislation:

“NYC Parks is committed to environmentally responsible pest management…[and] treats weeds where they grow, by manual or mechanical means whenever possible – hand pulling, mulching, cultural controls such as shading out sun-loving weeds, and planting robust weed-suppressive plants that can effectively compete with the weeds for light, air and water.

When that fails, or when resources do not allow, we spray Roundup, in complete compliance with NYC, NY State and Federal laws.”

Long-standing questions about Roundup

Months before the International Agency for Research on Cancer’s analysis was released this March, media outlet DNAinfo reported on two studies showing Roundup’s possible connection to non-Hodgkin’s lymphoma and breast cancer.

Glyphosate, and glyphosate formulations, were subsequently found by the IARC to have “induced DNA and chromosomal damage in mammals, and in human and animal cells in vitro.” This is important because our DNA manages cell reproduction, and DNA and chromosomal damage can become precursors to cancer.

Here’s a lengthy excerpt from Pollack’s March, 2015 New York Times article so readers can see how he frames the issue:

“Thirty years ago, an Environmental Protection Agency committee determined that the popular weed killer Roundup might cause cancer. Six years later, in 1991, the agency reversed itself after re-evaluating the mouse study that had been the basis for the original conclusion.

Now the issue is back again, in an even bigger way. An agency of the World Health Organization has declared that glyphosate, the active ingredient in Roundup, “probably” causes cancer in people. One piece of evidence the agency cites is that same mouse study.

The declaration drew an angry response from Monsanto, the maker of Roundup, which has accused the agency of having an “agenda” and “cherry picking” the data to support its case.

The conclusion is “starkly at odds with every credible scientific body that has examined glyphosate safety,” Philip Miller, Monsanto’s vice president for global regulatory affairs, told reporters on Tuesday. That includes a recent review by German government regulators on behalf of the European Union.

The new controversy and the reversal by the E.P.A. decades ago demonstrate how the same data can be interpreted differently and how complicated and politically perilous such a decision can be. But the discrepancy between Monsanto and the health organization can be partly explained by the specific way its agency analyzes the data.

Officials at the agency, the International Agency for Research on Cancer, said they had no agenda other than to inform the World Health Organization. They said the conclusion was based on studies of people, laboratory animals and cells.

“All three lines of evidence sort of said the same thing, which is we ought to be concerned about this,” said Aaron Blair, a retired epidemiologist from the National Cancer Institute who was chairman of the group of 17 reviewers from around the world; agreement on the classification was unanimous.

Glyphosate, introduced in the 1970s, is the most widely used herbicide in the world, sprayed on farms, in forests, on road sides and in gardens, and has a reputation for being benign, as pesticides go. It is now generic and used in many products, not only Roundup.”

Controlling weeds and rodents across 28,000 acres

Killing weeds and rodents are the main goals of pesticide use in the City’s parks, according to the Department of Health report. The Parks Department maintains 28,000 acres of parks, playgrounds, athletic fields, natural areas, recreational facilities, comfort stations, beaches, historic buildings, and parkways.

Herbicides account for the largest share -almost forty percent- of the Parks Department’s total pesticide use. Roughly another third of the Department’s pesticide use goes toward rodent control, especially rats and roaches.

In addition to Roundup, the Parks Department used two other herbicides in 2013 which contained glyphosate. Accord XRT, manufactured by Dow AgroSciences, was applied over four-hundred times. Glypro, also manufactured by Dow, was applied 103 times.

Council Member Kallos’ bill, which is co-sponsored by Council Member Helen Rosenthal, would require that the City use only biological pesticides, derived from natural materials, instead of synthetic, traditional pesticides–“except under necessary circumstances.”

The argument for bio-pesticides

Council Member Kallos’ office points to the fact that other U.S. cities, like Chicago, Portland and Seattle, are already moving to reduce the use of traditional pesticides in public spaces. Almost ninety percent of Chicago’s parks are reportedly pesticide-free.

Kallos also noted that the U.S. Environmental Protection Agency is moving to put new restrictions on glyphosate to “help address the rapid expansion of weeds resistant to the chemical.”

As an alternative, the EPA is advocating for greater use of biological pesticides. “Biopesticides are usually inherently less toxic than conventional pesticides,” says the agency.

They are also more precise. “In contrast to broad spectrum, conventional pesticides that may affect organisms as different as birds, insects, and mammals,” biopesticides generally affect only the pest being targeted and closely related organisms, says the EPA.

And biopesticides are often effective in very small quantities and tend to decompose quickly, adds the agency, resulting in lower rates of exposure.

A more labor intensive solution

At least 283.5 million pounds of glyphosate were used in U.S. agriculture in 2012- up from 110 million pounds in 2002. Biopesticides can greatly decrease the use of glyphosate, and other conventional pesticides, but they can’t eliminate their use altogether, says the EPA.

Biopesticides are just one component of an “Integrated Pest Management” program, whether you are a farmer or a large city, explains the EPA. Their effective use requires an understanding of pest management that is deeper than how to apply a chemical.

And controlling weeds without pesticides takes work. “Grass is kept taller to shade weeds and mowed more often. More aeration and overseeding are required,” notes the Chicago Sun-Times. But the Times points out that the city of Chicago’s decision to move away from traditional pesticides was also a financial one.

Will New York City follow suit and restrict the use of traditional, synthetic pesticides? No matter what, we will continue to hear about Roundup and glyphosate. Researchers are also beginning to question whether glyphosate can be linked to the problems currently affecting the nation’s honeybees.

More to come…




  • Central Park


    In 2011, New York State enacted the Child Safe Playing Fields Act banning pesticides at playing fields and playgrounds, excluding Central Park which has continued to use the banned pesticides exactly where children play (Sheep Meadow, etc). A recent NIH Consensus report placed pesticides at the top of the list of substances harmful to children and pregnant women, including increased incidence of ADD, ADHD and autism. Pets are also at risk.

    Please look at CENTRALPARKPESTICIDES for the supporting documentation including the Central Park Conservancy’s letter defending its use of banned pesticides and its practices generally keeping the public in the dark.

  • Central Park

    CENTRAL PARK PROTEST Sunday, Sept 10 2017 noon to 4pm at Sheep Meadow, Central Park
    is holding a silent protest (Sunday, September 10, 2017 from noon to 4pm in Central Park at Sheep Meadow) asking Central Park to stop using banned pesticides where children play.

    In 2010, New York State enacted the Child Safe Playing Fields Act which banned pesticides at school playing fields; NY State also listed alternatives to pesticides. Central Park, however, has continued to use banned pesticides exactly where children play (for example, Sheep Meadow). Protesters will wear masks over their mouths representing Central Park’s
    silence about its use of banned pesticides and their toxic effects. ​

    Nicki Franks, Barnard College sophomore and founder of,stated “Pesticides banned by New York law as unsafe for children at school are unsafe for children in the Park. As noted by the American Academy of Pediatrics and the Consensus Statement on Neuro-Developmental Risks linked on our website, children and pregnant women are uniquely vulnerable to pesticide exposure with studies showing increased incidence of ADD, ADHD and autism. Central Park puts up tiny 8.5×11 inch signs on the fence for a few days when it uses lawn pesticides.
    However, many pesticides are petroleum based and their toxicity lasts long after those tiny signs come down. The Park should not use banned pesticides where children play and large permanent signs should indicate
    where pesticides have been applied”.

    Ms. Franks added: “Central Park has kept park donors and users in the dark about its use of banned pesticides where children play. Our protest will inform about Central Park’s use of banned pesticides and show our support for NYC Council Bill 800 which limits chemical pesticides and Bill 754 which requires pesticide notification. Battery Park City has been successfully managed organically for 27 years and Harvard University switched to organic management of its sprawling campus in 2008 with excellent results. Green grass does not require harm to children and pets”.

    For further information contact:
    Ms. Nicki Franks