Brewing battle over Forest Service glyphosate spraying near Lake Tahoe’s pristine waters

Katherine Levy remembers a childhood deeply rooted in the natural offerings of Lake Tahoe – water skiing in the summer and working as ski instructor on the surrounding snow-covered mountains during winter months.

After leaving the area for many years, Levy recently moved back to live out her retirement along the lake’s north shore. But she doesn’t like what she has found upon her return: A US government plan to spray multiple types of herbicides – including the cancer-linked glyphosate weed killer – within national forest property that abuts the community’s cherished lake.

“I was horrified to find out what has been going on,” Levy said.

Levy is among a number of Lake Tahoe-area residents and officials who are fighting to block or alter the US Forest Service project, which is aimed at restoration of areas damaged by the 2021 Caldor Fire.

The wildfire burned through more than 200,000 acres in and around the Lake Tahoe Basin. The Forest Service manages more than 156,000 acres of National Forest land within that basin.

A town hall meeting was June 11 to strategize on how to fight the Forest Service plan, and residents are calling for action in various social media, including in posts on Facebook groups such as Lake Tahoe Locals and Keep Tahoe Blue.

The brewing battle is only one of similar fights over forestry pesticide use playing out across the US, but the Lake Tahoe issue has drawn the attention of leaders with the Make America Healthy Again (MAHA) movement, who have been lobbying the US Environmental Protection Agency to ban or severely restrict glyphosate use.

“The greater Tahoe community is shocked that the US Forest Service would even consider spraying glyphosate in its treasured, pristine forest, and is rapidly organizing to push back,” said MAHA leader Kelly Ryerson, who is helping organize opposition.

Glyphosate was introduced in the 1970s by the former Monsanto Co,. and brands made with the chemical, such as Roundup, have long been popular with farmers as well as homeowners and commercial landscapers. But in 2015, World Health Organization cancer experts classified the pesticide as probably carcinogenic to humans. The chemical is also linked to harms to animals, and federal regulators have found it could adversely impact over 90% of endangered species.

Worried about the water

Lake Tahoe has long been a popular tourist destination, recognized as the largest alpine lake in North America and unusually pristine. It sits in the Sierra Nevada mountain range, straddling the border of California and Nevada. Area residents are spread among 12 towns and two mountain villages.

“It is a major concern for all of us.” – South Lake Tahoe Mayor Cody Bass

Roughly 75% of the lake’s watershed is within national forest land and part of the area where spraying is proposed to take place sits on mountains above the lake where snow melt feeds into a tributary leading directly into Lake Tahoe.

“It is a major concern for all of us,” said South Lake Tahoe Mayor Cody Bass. “I had no clue that glyphosate was still being used in the forest. It was kind of a shock to me that we know what we know about it and still use it on public lands.”

Bass, who is also a local business owner, sits on the 15-person governing board of the  Tahoe Regional Planning Agency (TRPA). The TRPA strongly discourages the use of synthetic herbicides in the area and Bass is now asking the board to prohibit the chemicals. 

The TRPA sent a letter to the Forest Service’s Lake Tahoe Basin Management Unit on May 27 asking for a meeting with Forest Service officials. The letter notes that the TRPA and water quality officials want to minimize herbicide use “to the greatest extent feasible”.

Though Forest Service plans for the larger restoration project have been in motion for more than a year, the community only recently became aware of the work after an article in the Mother Jones news outlet mentioned that up to 75,000 acres affected by the Caldor Fire were targeted for glyphosate spraying. The plans include areas near Lake Tahoe ski resorts, Mother Jones reported.

A follow-up article by the outlet revealed in late May that spraying was already underway at one of the area’s ski and snowboard resorts south of Lake Tahoe within the Eldorado National Forest.

The herbicide spraying on public forest land in Lake Tahoe is not unique. From 2017 to 2020, 938,732 pounds of pesticide products were applied on 1,467,944 cumulative acres of federal forest service land throughout the US, according to federal data obtained by the Center for Biological Diversity (CBD).

“People think it’s this one off, but it is actually ubiquitous,” said Lori Ann Burd, director of the CBD’s environmental health program. “We expect there are going to be more and more of these spray projects. There is always some excuse that doesn’t make a ton of sense when you weigh that with the potential harms and risks.”

“Emergency” authorization

The Forest Service plan calls for the use of glyphosate and other herbicides to help clear areas of shrubs, brush and other vegetation before new tree plantings and to manage vegetation that might interfere with the growth of the trees after planting, according to the Forest Service.

In March, Forest Service officials said work to restore 11,700 acres within the Lake Tahoe basin warranted “emergency” authorization. Within the project, the service estimated 2,400 to 3,600 acres “may be treated with herbicides to support reforestation.” 

The herbicides would not be sprayed from the air, but from backpack sprayers to try to minimize damage to “non-target” native plants, and the Forest Service has said it will work to reduce the risk of the pesticides getting into streams and other waterbodies.

“Forest restoration involves targeted actions to facilitate post-fire recovery of the forested landscape; enhance resilience to wildfire, insects, and disease; and support wildlife species that depend on healthy forest habitats … “ the Forest Service stated in a 2025 proposal laying out its plans. “Proposed forest restoration treatments involve forest thinning and fuels reduction, reforestation activities (site preparation, planting, and competition release), herbicide treatment, and prescribed fire.”

The Forest Service lists glyphosate and four other herbicides in its plan for the continued restoration work, but most of the local outrage is over glyphosate and fears over risks to both human and environmental health.

When asked about the local opposition, Robert Lorens, the Forest Service’s National Environmental Policy Act (NEPA) planner for the project, acknowledged community concerns. 

He pointed to information on the Forest Service website stating that each herbicide used is properly registered with regulators, has undergone a biological review and has been determined to be the “best tool for achieving forest health or restoration.” The agency’s website also states that the Forest Service conducts a “rigorous and multidisciplinary assessment of each chemical” and its potential impacts.

The assurances are not calming resident fears, however.

“People come here from around the world because of its purity and natural beauty,” said Hannah Teter, who lives in the South Lake Tahoe area, close to the area impacted by the Caldor Fire, and works at a local wakesurf charter company. “The idea of spraying thousands of gallons of herbicides across the Tahoe Basin in an effort to dictate which species regrow after a natural wildfire is deeply troubling.”

She worries about her brother, who lives next door and is currently battling cancer. The use of glyphosate poses serious concerns for area residents, “especially those who are already immunocompromised and vulnerable,” Teter said.

Featured image of Lake Tahoe by Brandon Berry of UC Davis’ Tahoe Environmental Research Center.