YOUNTVILLE — Exit glyphosate. Enter clove oil.

A suite of environmentally friendly compounds are the new weed-killing tools of choice for Yountville, which has announced its phase-out of glyphosate, the ubiquitous herbicide entangled in recent high-profile lawsuits linking it to cancer.

The town Public Works department, which in recent years stopped applying glyphosate in parks and other public places, is turning to a combination of substances that do not carry the caution or warning labels federal law requires for potential toxins. With the change, Yountville is ending its last remaining use of Roundup-like products by town workers, Public Works Director Joe Tagliaboschi told the town parks commission Thursday night.

The decision follows a series of multimillion-dollar court judgments against Roundup’s inventor Monsanto Co., including an Oakland jury’s $2 billion award Monday to a couple who argued their use of glyphosate-based weed killer caused them to fall ill with non-Hodgkin’s lymphoma.

In Yountville, a town of some 2,900 people, glyphosate use had dropped from 8 gallons in the 2011-12 fiscal year to one gallon from July 2018 to this April, according to Tagliaboschi. Earlier, Yountville ceased spraying the herbicide in parks and other public places, restricting its use to roadways and its corporation yard west of downtown on the opposite side of Highway 29.

The key ingredient in Yountville’s new formula is Weed Slayer, a herbicide that contains 6 percent eugenol, an essential oil found in cloves and molasses. When applied to noxious plants, the substance usually takes effect in less than a week but can require up to 14 days in some cases, according to an information sheet from Weed Slayer’s Florida-based maker Agro Research International LLC.

The weed-fighting mixture also includes a soap-like surfactant to increase the effectiveness of Weed Slayer, as well as an acidifier to slow the herbicide’s degradation. Switching to plant-based products will require an increase in mulching and mechanical removal, to deny sunlight to invasive plants and to prevent them from regrowing from the roots even as their leaves die.

None of the components are among the substances listed as possible carcinogens under California’s Proposition 65, which requires public posting of the use of such products, according to Tagliaboschi.

The switch to a new product will carry trade-offs at least initially, he cautioned parks commissioners. Compounds based on eugenol and other plant-based ingredients are in high demand from other cities replacing Roundup, and some people may be bothered by Weed Slayer’s strong clove-like smell. Yountville will post signs in areas being sprayed with Weed Slayer is it did when applying glyphosate in the past, said Tagliaboschi.

Yountville opted for a clove-based herbicide despite some residents’ recommendations for vinegar-based alternatives, which Tagliaboschi said the town rejected due to the risk of skin and eye burns from their high concentration of acetic acid – up to 25 percent, five times the level found in kitchen-grade vinegar.

The town’s use of Roundup has likely paled next to the quantities of the chemical bought over the years by residents – who are not required to receive special training or protective gear to buy or use it, unlike public works staff – but Tagliaboschi suggested Yountville can set a public example for homeowners by distancing itself from the weed killer.

“Your neighbor probably has a 3-gallon jug of it in his garage, and a sprayer,” he said. “The best way to change behavior is by model behavior, and if people want to learn how to do it, the best thing we can do is put them in touch with the people teaching us how to do better.”

Yountville is at least the second municipality in Napa County to publicly avoid the use of glyphosate. Napa phased out its use in 2016 and 2017, and in March announced it would also forbid contractors from applying Roundup and similar herbicides on city property.

Introduced by Monsanto in 1974 under the Roundup brand, glyphosate quickly became one of the most commonly used anti-weed chemicals for both gardening and agriculture, effective on a wide variety of noxious plants. Records indicate the substance is used in more than 160 nations, and is applied to some 250 different crops in California alone. Special strains of corn and soybeans have been marketed for two decades as “Roundup Ready” for their ability to withstand spraying while surrounding weeds are killed.

In recent years, however, governments and research studies have questioned the federal Environmental Protection Agency’s stance that glyphosate does not increase cancer risk. A 2015 report from a branch of the World Health Organization labeled Roundup and similar products “probably carcinogenic,” and California added glyphosate to its Prop. 65 list of cancer-causing agents in July 2017, over the objections of Monsanto executives who unsuccessfully sought a court order to block the listing.

Juries in a series of California cases have sided with plaintiffs who blamed Roundup for their illnesses. A federal jury in San Francisco ordered Monsanto in March to pay a Sonoma County man $80 million. In August 2018, a San Francisco jury awarded $289 million – later cut by a judge to $89 million – to a former golf course greens keeper who blamed his cancer on Monsanto’s Roundup Ready herbicide.

The three California trials were the first of an estimated 13,000 plaintiffs with pending lawsuits against Monsanto across the country to go to trial. St. Louis-based Monsanto is owned by the German chemical giant Bayer A.G.

Bayer said Monday that it would appeal the latest, $2 billion verdict in Oakland. “The verdict in this trial has no impact on future cases and trials, as each one has its own factual and legal circumstances,” the company said.

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Information from The Associated Press was used in this report.


City of Napa/Town of Yountville Reporter

Howard Yune covers the city of Napa and the town of Yountville. He has been a reporter and photographer for the Register since 2011, and previously wrote for the Marysville Appeal-Democrat, Anaheim Bulletin and Coos Bay (Oregon) World.