San Francisco’s Pesticide Problem

SFRPD pesticide usage pie chart 2014Ever since the World Health Organization declared glyphosate (Roundup, Aquamaster) a probable human carcinogen in March 2015, San Francisco has had a problem: This is the herbicide most frequently used in San Francisco’s parks.

There’s only one good solution: A greater tolerance for “weeds.” The bad solution would be to substitute other herbicides that may be even more hazardous but which are less well studied. Or even ones that are acknowledged to be more hazardous than Roundup but are used anyway, like triclopyr (Garlon), the second most commonly used pesticide in our parks.


The San Francisco Recreation and Parks Department (SFRPD) uses Roundup Custom (or Aquamaster, it’s the same product) both in the Natural Areas and elsewhere in the parks. The pie chart here shows the pattern of herbicide use by active ingredient in 2014. In June 2015, after the WHO declared Roundup a probable carcinogen, the San Francisco Department of the Environment (SFDoE) reclassified it to Tier I, Most Hazardous, from Tier II, More Hazardous.

They haven’t stopped using it. Between April and September 2015, Roundup Custom has been applied nearly a hundred times in various places, including Golden Gate Park. Nearly half of those applications were in Natural Areas (like Glen Canyon, McLaren Park, Bernal Hill, Bayview Hill, Twin Peaks, and Billy Goat Hill). These are all places where people visit with their families, including children and pets.

We’ve been finding evidence that the herbicides in use in city parks are more toxic than most people realize. In April 2013, we compiled some of the information about Roundup in our article Pesticides and Cancer, Glyphosate and Gut Bugs. We’d asked San Francisco Department of the Environment, (which decides what pesticides can be used on San Francisco city properties) to reclassify glyphosate to Tier I as they actually did in June 2015 in response to the WHO decision. And these pesticides can become ubiquitous. Recently, a study in Argentina found glyphosate in sterile cotton gauze and even in tampons. We don’t know what the results for the US would show, but clearly glyphosate does not disappear from the environment as easily as its proponents suggest.


SFDoE is trying, through its Integrated Pest Management system, to reduce pesticide use. They’ve had some success; they claim an 80% reduction in pesticide use since 2003.

But it’s not enough. People are becoming much more aware of this pesticide use, and they’re fighting back.

The San Francisco Chronicle published an article, Pesticide Petition Grows: Glen Canyon Park neighbors lead drive to ban city’s use of herbicide in natural areas on November 1, 2015. The petition they refer to was initiated by Jill Fehrenbacher, and is addressed to Governor Jerry Brown. It has over ten thousand signatures. If you would like to add your signature, it’s here: Urge lawmakers to ban dangerous pesticide use at schools and public parks.

Children in a tree, Glen Canyon.

Children in a tree, Glen Canyon. This tree is gone. But children still play in the Canyon.

The article interviewed Ms Fehrenbacher, whose child goes to a preschool within Glen Canyon, and who is one of the many small children that play there. It interviewed Victoria Hamman, who suspects that pesticides caused her dog’s death by cancer.  [Edited to Add 12/5/15: We re-published an article about this by Dr Hamman ‘Did Roundup Kill My Dog?’.] It also quotes the San Francisco Forest Alliance.

“Herbicides are more toxic and more persistent than the public realizes,” said Rupa Bose, vice president of the San Francisco Forest Alliance, a nonprofit that supports the city’s nature. “We’re especially concerned about the natural areas where the public doesn’t expect herbicides. These are places where people gather blackberries, kids nibble on oxalis and dogs eat grass.”

(If the link doesn’t work, you can read a downloaded version of the article here: SFChronicleNov2015 article on pesticides )

glen canyon anti-poison signatures 1This has been an issue for us since the beginning of SF Forest Alliance, when we launched a petition aimed at SF city authorities in 2012 and got over a thousand signatures in only a few days. We think that as even more people become aware of the risks of herbicide use, the opposition to their use will become a tide.


Here’s why SFDoE’s Integrated Pest Management is not enough: They can only decide what herbicides to place on the permissible list, but it’s up to the land managers to decide when and how much to use. What’s really needed is a change in the goals. Roundup is even being used on sidewalks and playgrounds, and on greens and meadows – and of course in the Natural Areas.

Surprisingly, the sports fields and golf courses don’t routinely use much of any herbicides. There are exceptions; the renovation of Kezar Stadium used a huge amount of herbicides in 2014;  Harding, which is not managed by the city but under contract to the PGA Tour also uses a lot of herbicides to maintain tournament readiness; and in 2014, Gleneagles used a lot more herbicide than it was supposed to do owing to a contractor mistake.

As long as land managers believe that weeds are a major problem, pesticide use will be the most cost effective way to handle it.  But the dollar costs don’t count the risks of exposure. They also don’t consider that the risks will be borne unequally by the most vulnerable: Small children, whose small size and immature bodily processes make them susceptible; pets, who are in greater contact with vegetation and earth than most people; the chemically sensitive who react badly to herbicides.

Anise swallowtail butterfly breeds on fennel

Anise swallowtail butterfly breeds on fennel

The so-called Natural Areas are a particular problem. These are places where the public really doesn’t expect to find pesticides in use. It expects them to be wild and natural, places where children and pets can play in nature. The Natural Areas Program (NAP), which seeks to convert wild areas into Native Plant gardens, uses herbicides to fight plants it decides are invasive.

toddler holding oxalisThese include oxalis which provides nectar and which children love, the ever-popular blackberry that is a source of free berries in season besides providing habitat for birds and other wildlife, fennel that is the nursery plant of the the Anise Swallowtail Butterfly, and of course eucalyptus – the tree that San Francisco needs most to fight global warming and reduce pollution.

Pesticide PlanIn fact, NAP has a hit-list of 3 dozen species. Besides Roundup, it uses Garlon (triclopyr) which is even more toxic, especially to women, Stalker (imazapyr), and Milestone VM (aminopyralid). For a summary of the problems with each of these chemicals, read Toxic and Toxic-er: Natural Areas Programs Pesticides.

Many of the newer herbicides are potentially even more hazardous than Roundup, but because they are newer and not so widely used, there is less information about them. We would hate to see San Francisco shift from the devil we know to the one we don’t. We think people would much rather live with a few weeds in public places than have pesticides used to kill them.

The San Francisco Forest Alliance calls for No Herbicides in Our Parks.

Some pesticides are needed for health and safety: to fight mosquitoes, to prevent cockroaches, to remove yellow-jackets from areas where children play. But plants aren’t a health issue, and most herbicides don’t protect our health and safety – especially when they’re used in the so-called “Natural Areas” to create Native Plant gardens.

[Edited to Add on Nov 3 2015: We’ve made some minor edits to this article to clarify a couple of points.]

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6 Responses to San Francisco’s Pesticide Problem

  1. Dee Seligman says:

    Very simple to understand. Thank you for such clarity.

  2. Tony Holiday says:

    I so love what these guys call “weeds,” those who waste time volunteering to eradicate them. The way the yellow oxalis looks, for example, on the slopes of Glen Canyon during “rainy season’ – such beauty it’s a shame they can’t see. Fennel is a good-for-you edible herb. And I definitely saw less blackberries this year – another healthy edible for humans and animals. Leave nature alone – it’s there for people, their kids, their dogs and the critters who live in the parks to enjoy. Get a LIFE, anti-“weed” NAP-pers and cease and desist with the poisons. Excellent post.

  3. Philip Snyder says:

    Glycophosphate may or may not cause cancer, but a much worse product is Garlon. This herbicide will have to be used if profuse amounts over a prolonged time if cutting the Eucalyptis trees are cut to keep the roots from regenerating new sprouts. Any other method would be too labor intensive. Over 10 years ago while working on the original plan for Mount Sutro, I was stopped from reading information from the official Material Safety Data Sheet by the UC moderator who was alarmed at what I was reading. If they haven’t rewritten the MSDS, I would suggest that all concerned look up the MSDS on the internet and read it for yourselves.

  4. alicia snow says:

    Excellent post!  There’s nothing “natural” about the Natural Areas Program.  But with all the recent overwhelming evidence of cancer from herbicide use, how can officials of the NAP face their fellow San Franciscans?   These individuals are setting policy that deliberately endangers their neighbors.  It is actually in their power to protect their neighbors, their neighbors’ children and their pets, but they choose poisoning them instead.  Why not confront them and hold them accountable?  Why not sue the NAP for disregarding WHO warnings?  I’ll bet they would pay attention to that.

  5. Toni says:

    “Natural Areas” should, for the most part, be left to Mother Nature. Toxic chemicals have no place in San Francisco parks and natural areas.

  6. Christy Cameron says:

    How do I sign the petition?

    Sent from my iPad

    [SFForest: Hi Christy, here’s the petition: LINK. It has nearly 11,000 signatures now.]

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