Patches of snow dotted the ground when Canyon Mansfield stepped outside on March 16, 2017. The hill behind the 14-year-old’s home in Pocatello, Idaho, was not particularly large. At the summit, Mansfield would only be 300 yards from his house, and yet, he treasured the visits.
With its sweeping mountain view, the hill was Canyon’s refuge. His 3-year-old yellow lab, Kasey, was his constant companion there.
The two set off as usual that afternoon. Kasey was thrashing one of his toys when Canyon spotted a sprinkler-like object protruding from the ground. He ran a finger along the device. Suddenly, he heard a pop, and an orange cloud burst forth. Canyon lunged back as the front of his body was doused in chemicals. The burning began immediately.
As Canyon grasped for snow to irrigate his eyes, he heard Kasey grunting near the device. He called to him, but he didn’t come. He stopped what he was doing and ran to him. Dropping to his knees, Canyon watched as Kasey writhed in spasms. Frothing at the mouth, the dog’s eyes turned glossy. The boy didn’t want to leave, but he knew he needed help. He sprinted down the hill for his mother.
Canyon’s father, Mark Mansfield, a family doctor, was at work when the boy called for help. He raced home as fast as he could. Pulling into the property, Mansfield rushed to Kasey and positioned himself above the dog, prepared to perform mouth-to-mouth resuscitation. Canyon stopped him. It’s poison, Canyon said.
Kasey was dead, and Canyon’s head was pounding like never before. Toggling between his training as a physician and his horror as a parent, Mansfield struggled to sort out his son’s symptoms from the trauma he’d just experienced. He told Canyon to get into the shower immediately.
While his son cleaned up, Mansfield called the Bannock County Sheriff’s Office. A bomb and hazmat team were dispatched. Longtime Sheriff Lorin Nielsen was at a loss, trying to answer what felt like an absurd question: Who would plant a bomb in Pocatello?
Across the American West lies an untold number of potent chemical weapons, tucked away and waiting to go off. There could be one on your favorite hiking trail, or on the loop where you walk your dog, or in the woods where your kids play. Packed with sodium cyanide, these spring-loaded devices blast clouds of poison gas five feet into the air. Once inhaled, the lethal toxins mount a multidirectional attack on your cardiovascular, pulmonary, and central nervous system. Death can come in a matter of minutes.
The weapons, known as M-44s, are placed by an under-the-radar federal agency called Wildlife Services. The agency was created to protect the livestock industry’s bottom line by killing off the competition: namely, wild predators. The so-called cyanide bombs do kill predators, but they can also kill anyone else unlucky enough to stumble upon them. And they have a hair trigger.
Wildlife Services, which falls under the U.S. Department of Agriculture, is well known in conservationist circles. Most people, however, have never heard of it. For the uninitiated, a glimpse into the taxpayer-funded killing machine can be jarring.
In the past eight years, Wildlife Services killed nearly 21 million animals as part of its mission to oversee “the eradication and control” of species “injurious” to human endeavors, particularly ranching. While agents’ preferred means of killing is by air, with gunmen in helicopters and planes, M-44s were used to intentionally kill more than 88,000 animals from 2014 through 2022 — the period for which the agency has data available online. The total amounts to roughly 30 poisonings a day for much of the past decade.
M-44’s are part of “a broad strategy that also uses non-lethal methods, and that is informed by ongoing wildlife biology research,” Wildlife Services spokesperson Ed Curlett said in an emailed statement to The Intercept. Curlett added that 98 percent of the agency’s poison devices are placed on private lands and “only when the private, municipal, state, or federal landowner or manager requests assistance and enters a written cooperative agreement.”
According to Wildlife Service’s data, an additional 2,200 animals were killed unintentionally over the 2014 through 2022 period, including endangered species, domestic livestock, and pets like the Mansfields’ dog.
After losing Kasey, the Mansfields went on the offensive, suing Wildlife Services and traveling to Washington to spearhead legislation banning the use of M-44s. The hill behind the family’s home is managed by the Bureau of Land Management, an agency of the Department of the Interior. Idaho, at the time of Canyon’s poisoning, had banned M-44s on public land, but they remained legal on private land and on public lands throughout much of the rest of the country.
Surely, thought Mark Mansfield, the near-death of his child would motivate lawmakers to stop government agents from planting poison bombs everywhere. He was wrong.
The 2019 introduction of “Canyon’s Law” — a bill prohibiting M-44s on public land nationwide — went nowhere. “I don’t care if you’re red, blue, purple. I don’t care if you’re rural or urban. It just seems like a no-brainer,” Mansfield told me. “But somehow this still goes on. I’m shocked. I thought it would be a done deal within months. Call me naïve.”
Four years after it was written, Canyon’s Law was reintroduced last month by Reps. Jared Huffman, D-Calif., and Steve Cohen, D-Tenn. Sen. Jeff Merkley, D-Ore., introduced companion legislation in the Senate.
“This is remarkable. They weren’t prompted. We didn’t have a clue that they even knew this hearing was going on.”
After years of setbacks, advocates in the Mansfields’ corner believe the tide may finally be turning against M-44s — thanks to the emergence of an unexpected but critical ally. During a congressional hearing on Canyon’s Law last summer, the Department of the Interior submitted a statement outlining its M-44s position. “The Department is concerned that these devices pose a risk of injury or death to unintended targets, including humans, pets, and threatened and endangered species,” the statement said. The Department had “no technical objections” with the proposed bill “and would work to implement the legislation, if enacted.”
Brooks Fahy, the executive director of Predator Defense, a national wildlife advocacy group, was shocked. While the Department of Agriculture manages 193 million acres of public land in the U.S., the Department of Interior manages 245 million. The scale alone made the statement highly significant. That the largest land management agency in the country would take a critical position on the issue was unprecedented. “This is remarkable,” Fahy told me. “They weren’t prompted. We didn’t have a clue that they even knew this hearing was going on.”
Sensing an opportunity, Predator Defense and the nonprofit Center for Biological Diversity rallied organizations focused on wildlife preservation in the West. With more than 70 allied groups joining them, the groups filed a formal petition last month, on the heels of the reintroduction of Canyon’s Law, calling on the Department of Interior to ban the use of M-44s on its lands.
Success won’t come easy though. Behind the M-44 lies a well-connected industry that’s influenced the government’s predator killing program for generations, one that’s unlikely to relinquish its bombs without a fight.
Years of Hell
Mark Mansfield had to figure out two things after his son was poisoned: What was the toxin, and who was responsible?
Luckily, one of the sheriff’s deputies had worked as a federal trapper. He suggested contacting Wildlife Services. Nielsen, the sheriff, had never heard of the agency and had no idea that it was mining his county with spring-loaded poison sprayers.
Mansfield, too, was puzzled. He was even more taken aback when Todd Sullivan, the Wildlife Services supervisor who planted the device, showed up at his house.
“He killed my dog and he had nearly killed my child,” Mansfield said. “At that point in time, there was a lot of stress. It was very difficult for me not to, you know — whatever.”
The family was kept inside while Sullivan escorted law enforcement up the hill. Unbeknownst to the sheriff’s department, Wildlife Services had planted 18 cyanide bombs throughout Bannock County. Sullivan had placed the M-44 that poisoned Canyon and killed Kasey in plain view of the Mansfields’ backyard, a second device 60 feet from the first, and two more elsewhere in the neighborhood.
The public land behind the Mansfields’ home abutted private property, where a local sheep producer had leased an allotment to raise his stock. In an interview with a Bannock County detective, Sullivan said he meant to plant his bombs on private land, in accordance with Idaho law, and while he had the means to differentiate between jurisdictions, he didn’t. The Wildlife Services supervisor also admitted that there had been no livestock predation cases in the area. He was simply trying to “get a jump on the season” by poisoning any coyotes that might pass through.
“It was three years of hell for his parents and more so for him.”
In his thousands of hours in the emergency room, Mark Mansfield had never dealt with a sodium cyanide poisoning. He called specialists around the country to gather as much information as he could. It did not look good. As one toxicologist explained in a 2019 interview, sodium cyanide’s effects on the human body are similar to those of sarin gas, an internationally banned chemical weapon used in war zones.
Canyon’s pounding headache worsened with admission to the ER. He experienced nausea and vomiting on a near-daily basis. His hands and feet went numb. The worst of it lasted more than a month, but the long-term effects, from migraines to mood changes, lingered for years.
“Finally, about 2020, he was back to his baseline,” Mansfield said. “It was three years of hell for his parents and more so for him.”
A Family Fights Back
In the days after Canyon was poisoned, his father received an unsolicited call from Fahy, the Predator Defense executive director. “A lot of people helped us,” Mansfield said. “But he was the one who explained it to us.”
Fahy’s first encounters with Wildlife Services began in the 1970s, when the agency was still known as Animal Damage Control. Working as an investigator for the Humane Society in Oregon, he encountered the mummified remains of snared coyotes and orphaned pups at dens in rural areas throughout the state. He started Predator Defense a decade later as an animal hospital before transitioning into advocacy.
Fahy had witnessed the physical damage Wildlife Services’ traps can do but found the agency’s arsenal of poisons more unsettling. “You can’t remove it,” he said. “That poison is in their system and watching an animal die slowly, whether it be from sodium cyanide or strychnine or compound 1080, is extraordinarily disturbing.”
Fahy can rattle off cases going back years. There was the Wildlife Services trapper who scattered M-44s around a Christmas tree farm. And the one who hanged coyote carcasses on a family’s fence after killing their dog. And then there was Dennis Slaugh.
A heavy equipment operator from Vernal, Utah, Slaugh had little in the way of money but took great pride in the work he did for the county. That ended following his brush with an M-44 in 2003. Plagued with daily vomiting, diminished breathing, and soaring blood pressure, the 61-year-old was forced to quit his job. Wildlife Services denied any fault in the matter and claimed that Slaugh exceeded the statute of limitations to file a claim of wrongdoing. Unable to work, the medical bills piled up as Slaugh’s health deteriorated.
“They took my life away,” Slaugh said in a 2020 documentary. “And now I can’t hardly change a light bulb. It’s all from this cyanide. It just took everything away from me.”
As the years went by, Fahy collected case after case of M-44s killing pets and harming people across the West. Never once, he said, did he encounter an incident in which Wildlife Services, per the M-44 use restrictions required by the Environmental Protection Agency, contacted local medical providers to inform them of devices planted in their area. Signage was another problem. A trapper may place a single sign at one entrance on a large plot with several entry points, or they might not place one at all. Both were common in the investigations Fahy undertook.
Fahy had never seen a case quite like the Mansfields’ where a child came so close to death. He shared everything he knew with the family. In June 2018, the Mansfields filed suit against Wildlife Services, accusing Sullivan of failing to follow a slew of regulations meant to govern the placement of M-44s, including the placement of warning signs.
The Justice Department initially responded by blaming Canyon and his parents for what happened, before admitting Wildlife Services’ negligence and agreeing to pay the Mansfields $38,500 to settle the case in 2020.
Thick as Pudding
Despite the national coverage the Mansfield case received, Wildlife Services has clung to M-44s as “an effective and environmentally sound wildlife damage management tool.”
In the wake of Canyon’s poisoning, the agency published a brochure justifying the devices’ use. “Our use of M 44 devices strictly follows EPA label instructions, directions, and use-restrictions; applicable Federal, State, and local laws and regulations; and agency and program directives and policies,” it said. “Our personnel do not use M-44s on any property unless the land’s owner or manager requests and agrees to our assistance. We must have a valid written cooperative agreement, agreement for control, Memoranda of Agreement, or other applicable document signed by the landowner or authorized representative to place any M-44s.”
After years of bad press, Wildlife Services is acutely aware of its reputation as the “hired gun of the livestock industry.” The source of the oft-repeated description is Carter Niemeyer, formerly one of the agency’s most productive trappers and today one of its sharpest critics.
“Their lobbying power makes or breaks Wildlife Services.”
Niemeyer is the author of “Wolfer,” an account of his quarter century as a Wildlife Services supervisor in Montana from 1975 to 2000. The veteran trapper believes the agency has important elements to its portfolio, and that many of its East Coast operations are quite professional. But in the West, he argues, existential ties to the livestock industry still reign. Unwillingness to relinquish M-44, he says, is an artifact of that bond.
“The very existence of Wildlife Services is dependent upon the livestock industry and all of the cooperators,” Niemeyer told me. “Their lobbying power makes or breaks Wildlife Services. If the cattlemen and sheep men lost their faith in Wildlife Services and didn’t do this insistent, persistent, powerful lobbying that they do, Wildlife Services would be dead in the water and probably disappeared.”
One of the starkest examples of that power came in 1998, when then-Rep. Peter DeFazio, D-Ore., introduced a bill to cut Wildlife Services’ budget from $50 to $10 million by taking an axe to its predator killing program. DeFazio was a longtime critic of the program, often telling reporters that Wildlife Services was more secretive than the intelligence agencies he worked with on the House Homeland Security Committee. His bill passed, but in a highly unusual turn of events, it was subjected to revote less than 24 hours later. The American Farm Bureau was in a fury. Overnight, agriculture lobbyists convinced 38 members of Congress to change their minds. The proposal died the following day.
“They were against the ropes, and it was all over,” Niemeyer said. “And in the last minute of the last hour of the last second, the livestock industry lobbyists somehow got to enough congressmen to turn the whole thing around and get that budget back when we’d pretty much heard that it was a done deal.”
Niemeyer never used M-44s and didn’t like them. The trappers who worked for him mostly felt the same. They were dangerous, required lots of paperwork, and trappers had plenty of other tools to do their jobs. “I was not disappointed if a guy didn’t want to use him,” Niemeyer said. “I didn’t blame him. I wouldn’t have either if I was in their shoes.”
There was one problem.
“My walking orders as a supervisor was to make sure the men used them,” Niemeyer said. “There was a real push from higher levels of the livestock industry to push for their registration and push for their use. Some of the sheep men, some of the notorious ones I remember, they figured that if you got snares, put ’em out. You got traps. Put ’em out. And for God’s sake, if there’s M-44s and you got a bunch sitting there in your cabinet, put ’em out.”
In its 2019 brochure on M-44s, Wildlife Services pointed to tens of millions of dollars lost every year by ranchers due to livestock killed by predators. Those numbers, Niemeyer pointed out, reflect survey data, self-reported by ranchers. They are not independently verified.
Though Niemeyer’s Wildlife Services tenure ended more than 20 years ago, the livestock industry’s continued support for M-44s is evident today on the webpage of the American Sheep Industry Association, which represents more 100,000 sheep producers nationwide. The site features a dedicated “Fact versus Fiction” page on the issue of M-44s. Among the fictions listed is the notion that cyanide bombs present a risk to the public.
At this point, Niemeyer argued, clinging to M-44s is as much about symbolism as anything else. “Kinda like the old give ’em an inch, they take a foot,” he said. “If they take our M-44s, next year they’ll take our snares, and then the year after they’ll take our traps.”
There’s a material angle as well. In addition to federal funding, Wildlife Services relies on the financial support of “cooperators” to keep the lights on. In the case of its predator program, the cooperators are often agricultural interests.
“They’re thick as pudding,” Niemeyer said. “That lobbying power of the ag industry is what keeps Wildlife Services afloat. I wouldn’t call it a criminal, but they’re buddies. They needed us and we needed them, and that’s how it keeps going on to this day.”
Six years on, it’s impossible to measure the full impact that the poisoning had on Canyon, said Mansfield. “You’re not really going to have a control group on kids nearly killed by cyanide,” he said. “So anything and everything that ever happens to him, mentally and or physically, you say, ‘Oh, I wonder if cyanide has anything to do with that?’ It’s a haunting thought that comes up every single time.”
The family’s goal remains the same: getting Canyon’s Law passed. They are hopeful that the latest round of efforts will be the final push they have been waiting for.
Following Canyon’s poisoning, Idaho issued a statewide prohibition on the use of M-44s pending an environmental assessment that remains in effect today. Fahy, the Predator Defense advocate, had little time to celebrate.
“It literally ripped my guts out, the whole thing, what they got away with.”
In February 2018, he picked up the phone to learn that Dennis Slaugh passed away. The official cause was an acute myocardial infarction. Listed among his “conditions contributing to death” was “Cyanide Poisoning/Exposure From M44 Device 2003.” The words on Slaugh’s death certificate contradicted a claim on Wildlife Services’ brochure the following year — repeated on American Sheep Industry Association’s fact versus fiction page — which read: “No human fatalities have been associated with Wildlife Services’ use of M-44s.” When asked about the death certificate, Wildlife Services pointed to a 2008 federal investigation that purportedly cleared the agency of any culpability in Slaugh’s death.
Fahy was devastated. He, Slaugh, and Slaugh’s wife Dorothy had traveled to Washington together a decade before, urging lawmakers to act on M-44s before somebody was killed. Slaugh had never visited a city like D.C. before. He didn’t know what to expect, and he didn’t know what was happening inside his body — why, for example, he needed to pause periodically to vomit as he passed through the halls of the Capitol.
Looking back at a photo from the visit, Fahy notes the way Slaugh held Dorothy’s hand, squeezing it tightly. “He was scared,” Fahy said. He watched Slaugh’s slow and agonizing deterioration in the years that followed. His death was the outcome Fahy had dedicated his life to preventing.
“It literally ripped my guts out, the whole thing, what they got away with,” Fahy said. Approaching 70, Fahy has had his own health scares — a consequence, he believes, of internalizing decades of secondhand trauma. With Slaugh’s death, however, he vowed to continue their fight. Unlike Canyon’s poisoning, where at least there was some measure of accountability at the local level, he said, “with Dennis, Wildlife Services got away with it.”
“I find it unbelievable that there are people that could have treated him like that,” Fahy said. “Nobody stood up for him. They just walked right over him.”