Aerial spraying of chemicals — including one banned in Europe  to kill sagebrush and invasive plants appears to be “the most-reasonable option” for the Bighorn National Forest to meet range and habitat goals, the U.S. Environmental Protection Agency says.

The EPA made its comments on the national forest’s proposal to kill mountain big sagebrush, native larkspur and non-native weeds in a July letter to Forest Supervisor Andrew Johnson. Administrators of the 1.1-million-acre Bighorn National Forest would attack invasive Medusahead and Ventenata grasses, plus the native sagebrush and larkspur, to preserve wildlife habitat, improve domestic stock grazing and reduce the threat of fire, according to a draft environmental impact statement.

The Bighorn plan “appears to be the most-reasonable option” to achieving the national forest’s desire for up-to-date and effective “vegetation overgrowth management techniques,” wrote Philip Strobel, the EPA’s regional director for compliance with environmental law. The letter lends an imprimatur for the project from a significant federal partner tasked with overseeing toxic substances and pollution.

The EPA endorsement of the national forest plan may assuage some worries about both aerial spraying, which critics said would hit untargeted areas, and the proposed use of the herbicide tebuthiuron, which is banned in Europe.

The chemicals “have all been registered by EPA and provide more selective and effective options for controlling targeted plant species,” Strobel wrote. “Aerial applications will cover areas not easily accessible for ground application and will be more effective for treatments in large areas with fewer applications.”

Several environmental, community and bird groups have criticized the Bighorn plan. The Forest Service has not provided copies of comments, but the EPA gave its letter to WyoFile following a records request.

But the plan falls short…

Despite EPA support for elements of the long-range Bighorn proposal, the environmental agency echoed others’ criticism of the draft 246-page draft environmental impact statement. The Bighorn Forest, which stretches from Montana to Tensleep, from Story to Shell, had to complete that study to authorize aerial spraying.

The Forest Service was imprecise in describing how much acreage it would treat to reduce mountain big sagebrush, the EPA said. The EIS also is vague when it comes to describing how big the overall vegetation treatment area would be, the environmental agency said.

A female broad-tailed hummingbird feeds in Colorado. (David Inouye/U.S. Geological Survey)

The national forest’s descriptions of its proposed eradication and reduction program could span an area that could be more than five times as large as indicated in the EIS, depending on how one reads the document, the EPA suggested.

“[I]t is unclear in the Draft EIS that the maximum treatment of 15,000 acres of mountain big sagebrush over two years will satisfy the project’s desired conditions rapidly or whether 76,500 acres (5,100 acres per year for 15 years) is the goal,” Strobel wrote.

Similarly, the forest’s description of total treatment acreage for all types of vegetation could be interpreted widely, the EPA said. “[I]t is never clearly identified if 79,650 [acres] or 375,000 acres of treated vegetation is the goal,” the letter reads.

National Forest officials also should map where the herbicides are to be sprayed and where vegetation would be otherwise killed. “We recommend the USFS include waterbodies, wetlands and other sensitive areas on maps near treatment areas,” Strobel wrote

Finally, the Forest Service should look to changing domestic stock grazing methods as part of its strategy, the EPA said.

“[T]he Draft EIS does not discuss additional changes to livestock grazing protocols in the BNF that could be incorporated to avoid disruption or restoration of the natural vegetation regime with minimal mechanical, chemical, or biological interventions,” Strobel wrote. “We recommend that the Final EIS evaluate if there are additional modifications or best practices the BNF can adopt for livestock grazing to lessen the overall need for human interventions in the management of mountain big sagebrush over the next 15 years.”

Western Watersheds Project has criticized the project saying the Bighorn Forest has “a fictional understanding of sagebrush ecology.”

The Council for the Bighorn Range has said treating sagebrush and removing larkspur “are not beneficial to the myriad of sage-dependent birds that inhabit the sagebrush-steppe.” The Bighorn Audubon Society called the proposal to thin sagebrush “a very unreasonable plan that purposely further reduces bird and other wildlife habitat.”

Angus M. Thuermer Jr. is the natural resources reporter for WyoFile. He is a veteran Wyoming reporter and editor with more than 35 years experience in Wyoming. Contact him at or (307)...

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  1. I looked up an article about spraying big sage brush in Wyoming in the 1950s because I had heard that huge tracts of land were sprayed from the air in order to increase grasses for grazing. It appears they used 2,4-D at that time and it has a long half life – I think they treated over a million acres in our area alone. Incidentally, the use of 2,4-D fell out of favor but recently the EPA approved it for being added to Roundup since some plants were developing immunity to Roundup -they expect the use of 2,4-D to increase by 100-600% due to this EPA ruling – but now, the evidence is mounting about the negative affect of 2,4-D on human health at the same time the EPA has given a go ahead for its use.
    Also learned at the VFW last night that snow used to lie in the shade of big sage brush well into June in the 5,000 – 6,000 foot elevations thus providing needed moisture – since the big sage brush was sprayed some of the springs have dried up.
    One article said dioxins were being added to the chemical spraying mixtures the USFS used until the mid 1990s – not a lot, but enough to be of concern. Latest estimates are that over 300,000 Vietnam vets have died young due to the dioxin in agent orange – the death toll from spraying by the US government far exceeds the combat deaths – and that doesn’t include an estimated 4,000,000 civilians that were sprayed. The US governments track record is down right deadly when it comes to spraying toxic chemicals – and EPA goes along with a lot of it. Very, very concerning behavior.

  2. I haven’t reviewed the USFS’s proposal so these comments are general in nature;

    1.) The Powder River Basin Resource Council and Wyoming Outdoor Council may be interested in appealing the USFS decision to federal court and argue;

    2.) The proposed plan did not include an alternative utilizing goats for weed control;
    3.) Wyoming big sage brush is a host species for certain species that are on the states list of species in greatest conservation needs and should not be sprayed;
    4.) The USFS proposal did not analyze the affect of Spike on municipal drinking waters and aquatic species;
    5.) The USFS proposal did not consider best available science developed in Europe and Australia;
    6.) The USFS proposal did not adequately consider the half life and duration of Spike in the soil;
    7.) The USFS proposal did not consider whether or not livestock grazing in the sprayed areas can pick up and accumulate Spike in their bodies – certainly not organic beef.
    8.) A finding of ” No significant impact ” was in error and the USFS needs to do a full EIS on the proposal;
    9.) And more ……………….

    These are just some possible arguments off the top of my head which may or may not be applicable – there are quite a few interesting factors to consider though.

    1. P.S. The above arguments can only be appealed in federal court if the appealing party commented on them during the comment period – that’s why its so important to comment during the specified period – if you don’t submit comments you usually give up your right to appeal later – a big factor!!

  3. Mike and Lisa Kimsey of Manderson, Wyoming have a business called ” Big Horn Basin Boers ” which provides goats for weed control using natural solutions. Please Google ” Kimsey goats Wyoming ” for information about their business. A much better approach to invasive weeds than spraying and they are only a few miles away from the Big Horns. They are willing to go but the USFS must have the foresight to use natural treatments. DA.

    1. P.S. Internet articles about Game and Fish using Kimsey goats at the Yellowtail Wildlife Management area east of Lovell and in other projects in Montana – 1500 total goats available for weed control.

  4. I say absolutely no spraying no chemicals The bighorns are one of the only pristinish areas left Just a bored range manager from saint elsewhere needing a project Absolutely heartbreaking

  5. No herbicides in the bighorns no intervention We have one of the few pristine areas in the country Absolutely disgusting idea Just some range manager wanting a project

  6. Ask the elk,deer,antelope and Sage grouse if big sagebrush is a noncrop.From fall to early spring they may disagree.

  7. Yeah, lets spray the whole state with Round-up and Spike. Then there should be no grass or sagebrush to fight over. NOT! Stop it. Bad plan. BS

  8. Tebuthiuron, sold by Dow Chemicals under the consumer brand name of Spike, is a highly water-soluble non-selective herbicide with a half life persistence of a year or longer. It acts by absorption through the roots, and disruption of photosynthesis. It is commonly used to kill woody plants such as Big Sagebrush, and because of its water solubility should not be used near wetlands, where it is also highly toxic to aquatic vegetation. It is being studied as a persistent pesticide of concern in Australia, and has been banned in Europe. This poison should not be financed by the public to be sprayed on public wildlands.

    1. Linda: The runoff from the Big Horns becomes the municipal water supply for Buffalo, sheridan, Worland, Basin, Greybull, and Lovell – I doubt if the towns are even aware of the Spike getting into their water supply. That half life is really concerning as is the water solubility which means ability to be transported in solution for many miles – I wonder how this affects the fish in the mountain streams – does the food chain result in an accumulation in their muscles and do the fish have the ability to metabolize the chemical or does it stay in the liver??? Really a bad idea. By the way our top chemical engineer from SDSM&T went to work for DOW and got chemical poisoning so bad he committed suicide at a young age – DOW never divulges these tragedies.

  9. Aerial spray native plants like Wyoming big sagebrush, Artemisia tridentate, designated as the state’s official shrub only continues the USFS war on wild flora and the wildlife dependent on it. Sagebrush is one of the most important browse species for wildlife and should be protected not killed. The USFS proposal for aerial spraying toxic chemicals on the Bighorn National Forest is only adding another nail in the coffin of flora and fauna extirpation in Wyoming.
    Cease and desist.

    1. YES, cease and desist. No more chemicals in our environment please! Should be more than enough unemployed and cons in Rawlins that a good start would be manual weeding with some pay for services. BS

  10. The USFS has a long history of poisoning the American people with aerial spraying. I found the following article:
    They even have sprayed dioxins/agent orange including on adjacent private land and water sources. EPA and USFS employees need to take a refresher course called “Cancer 101 “. Outrageous conduct – as usual, Federal court is the only chance of stopping it – witness the number of cases in Federal court concerning cancer causing organic chemicals and the huge damages awarded – as usual, the system lets the poisoning occur for many, many years, and then after the scientific evidence links cancer to the organic chemical – the government finally does something – well, maybe does something. So cancer rages on.

    1. P.S. Sometimes the only way to stop this is for the Gerry Spences, Erin Brochovichs and Karen Silkwoods of our country to fight the whole system in court.