YOUNTVILLE — A week and a half after California added one of the world’s most heavily used weed-fighting chemical to its list of cancer-causing substances, Yountville detailed its progress toward lessening its use – but added it will not yet shelve it completely.
Yountville more than halved its spraying of chemical herbicides, mainly glyphosate, over the last five years but has no plans to sideline the product, Public Works Director Joe Tagliaboschi told the Town Council last week.
The town’s announcement followed the July 7 posting of the weed-killer widely sold as Roundup onto the state’s list of known carcinogens. Under Proposition 65, the state’s Office of Environmental Health Hazard Assessment keeps a roster of several hundred chemicals it says can cause cancer, produce birth defects or harm fetuses.
The town reported cutting its use of herbicides including glyphosate from 8 gallons in 2011-12 to 2.95 gallons in the 2016-17 cycle that ended June 30. Tagliaboschi said the reduced spraying is largely the result of other practices like hand-weeding, mulching and drip irrigation, practices that lower the quantities needed of any kind of herbicide.
But lowering the amount of glyphosate to zero, however, is not yet in the cards, he added, saying its stocks of glyphosate and Turflon Ester — the only weed killers used by the town — remain labeled with the lowest of four caution levels issued by the Environmental Protection Agency. Herbicides and pesticides in the other three categories are required to be labeled “caution,” “warning” and “poison” — the most severe classification — based on their toxicity.
Alternative weed-attacking agents can use natural acids such as vinegar or citric acid, but present their own hazards to those using them, Tagliaboschi told the council. For a vinegar-based spray, the acidic content would be about 25 percent – five times the concentration of the food-grade version – and the risk of skin, eye and lung injuries would require Tyvek suits, respirators and gloves for protection, he said.
Any risk of glyphosate spraying would be higher for home users rather than town workers, who are required to receive safety training under state and local law, according to Napa County Agriculture Commissioner Greg Clark.
“The greatest risk is to the person handling the concentrate,” he said Tuesday. “… It’s very easy for a homeowner to go to the store and buy something, but not be as trained or prepared (as a town employee).”
Introduced in 1974 by Monsanto Co. under the Roundup brand, glyphosate became one of the most common herbicides for farming and gardening alike, effective on a wide variety of noxious plants, officials said. Sales increased further starting in the late 1990s with the arrival of “Roundup Ready” soybean and corn strains that could endure spraying while surrounding weeds died, statistics show.
Glyphosate is used on 250 different crops in California, the nation’s leading agricultural producers, and is sold in least 160 nations, records show.
However, research studies in recent years called its safety into question, culminating in a 2015 report by a branch of the World Health Organization that identified the herbicide as “probably carcinogenic” to humans. (Roundup has not been branded a cancer risk by the EPA.)
The company also reportedly faces lawsuits connected to glyphosate, including a case in San Francisco federal court alleging a link to non-Hodgkin’s lymphoma, a connection the company denies. Plaintiffs in that case have cited emails from a Monsanto executive suggesting an effort to ghostwrite pro-Roundup reports and attach the names of academics to vouch for its safety.
In response, California regulators announced plans to add Roundup to its state list of known cancer-causing agents, a roster created after Proposition 65’s passage in 1986. Monsanto sued the state to block the classification of glyphosate as cancer-causing, but a Fresno County judge dismissed the company’s bid in January.
Locally, the debate over glyphosate flared up in February 2016 after members of a Napa-based Nextdoor social media page alerted townspeople to a scheduled spraying at Fuller Park. Although city parks directors said the chemical is used only on planter boxes and bare ground rather than lawns, opponents called on Napa to try alternative weed killers based on vinegar, clove oil and other natural materials.
Napa has since announced plans to phase out Roundup in its parks, and rely not only on other substances but on mechanical removal as well as mulching to deny light and air to weeds. In time, the city will limit its use of glyphosate to streets and rights of way, parks and trees director Dave Perazzo said in April.
Other towns in California have gone further to distance themselves from the herbicide. City councils in Irvine and Encinitas reportedly have ordered an end to glyphosate use, as has the school district in the Los Angeles suburb of Burbank.
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