Originally published 2019-08-26.
M-44s are spring-loaded devices that fire a dose of sodium cyanide powder into the mouth of an animal that tugs on a baited head. Critics call them “cyanide bombs.” In August 2019 the U.S. Environmental Protection Agency (EPA) allowed them to stay in use on an interim basis, despite a wave of public objections, and in December 2019 it tightened the rules after a backlash. Here is what the devices are, what the 2019 decisions actually said, and why the fight over them has lasted for decades.
What an M-44 is, and why the nickname is misleading
Despite the “bomb” label, an M-44 does not explode. It is a small tube driven into the ground with a capsule holder on top, wrapped in material scented to attract canines. When an animal bites and pulls on it, a spring ejects sodium cyanide into its mouth. The poison reacts with moisture to release hydrogen cyanide, which blocks the body’s ability to use oxygen, and death usually follows within minutes.
The devices are aimed mainly at coyotes and foxes that prey on sheep, goats and calves. The main user is Wildlife Services, a branch of the U.S. Department of Agriculture that removes animals considered a threat to livestock, crops, airports or public health. A handful of state agencies are also licensed to use them.
The problem critics point to is simple: the device cannot tell a coyote from anything else curious enough to pull on it. Dogs, foxes, raccoons, opossums, skunks and even bears have been recorded among the victims, and people have been exposed as well.
What the EPA decided in August 2019
Sodium cyanide is registered as a pesticide, so it goes through the EPA’s periodic safety review. In early August 2019 the agency issued an interim decision that kept M-44s legal while the review continued, with a final decision expected after 2021. The approval covered Wildlife Services nationwide and state agencies in Montana, New Mexico, South Dakota, Texas and Wyoming.
The August version came with modest new rules. According to the Center for Biological Diversity, devices had to sit at least 100 feet from a public road or trail, up from 50 feet; elevated warning signs had to be placed within 15 feet of each device rather than 25; and residents living within half a mile of a placement had to be notified.
Opponents said this changed little. Collette Adkins, carnivore conservation director at the Center for Biological Diversity, put the group’s position bluntly: “Cyanide traps can’t be used safely by anyone, anywhere.” Brooks Fahy of the group Predator Defense called the decision a “complete disaster,” as High Country News reported.
The numbers behind the dispute
Federal records, as summarised by conservation groups, show how widely the devices have been used:
- 2016: about 13,530 animals killed by M-44s, including 321 that were not the intended target.
- 2017: 13,232 animals.
- 2018: 6,579 animals, mostly coyotes and foxes, with more than 200 non-target deaths, including foxes, opossums, raccoons, skunks and a bear.
- 2019 and 2020: about 8,200 and 7,691 animals respectively; in 2020 the non-target victims again topped 200, including a black bear and five dogs.
For scale, Wildlife Services reported killing more than 1.5 million native animals by all methods in 2018, so M-44s are a small slice of its work. They draw attention because poison left unattended in open country is indiscriminate in a way a targeted method is not. Critics, including former agency employees, also argue the official tallies understate the true toll, since an animal that wanders off before dying may never be found.
Supporters of the program, mainly livestock producers, see it differently. Predation can cost a small ranch real money, and they argue that M-44s let them deal with specific problem animals without the wider disturbance of shooting or trapping.
Why the public comment figure needs context
When the EPA opened its proposal for comment, the Center for Biological Diversity and the Western Environmental Law Center reviewed more than 22,000 submissions and found that over 99.9 percent asked for a ban. That is a striking level of opposition, but it should be read for what it is.
Public comment periods are not opinion polls. People who feel strongly, and organisations that encourage members to write in, are far more likely to take part. The figure shows that the people who engaged with the process overwhelmingly opposed M-44s; it does not prove that 99.9 percent of Americans do. It is still a meaningful signal, and the EPA itself changed course within months.
Canyon Mansfield and the incidents that shaped the debate
Much of the modern opposition traces back to one afternoon in Pocatello, Idaho. On 16 March 2017, 14-year-old Canyon Mansfield was walking his yellow Labrador, Casey, on a hill behind the family home when he touched what he thought was a sprinkler head. It was an M-44. The device sprayed him and the dog with orange cyanide powder; Casey died in front of him, and Canyon was hospitalised and reported vision problems afterwards.
The case led Wildlife Services to stop using M-44s in Idaho, a halt that later became part of a lawsuit settlement. The Mansfield family sued the federal government, and the incident became the face of a national campaign. A bill named Canyon’s Law, introduced by Oregon congressman Peter DeFazio, proposed banning the devices on federal public lands, though it did not advance to a vote.
Other states acted on their own. Oregon passed a statewide ban, signed by Governor Kate Brown in 2019, that took effect in 2020. In Colorado, Wildlife Services agreed in 2017 to pause M-44 use after environmental groups sued.
The December 2019 reversal
The criticism had an effect. On 5 December 2019 the EPA withdrew its August interim decision and issued a new one that it described as more protective. Under the revised rules, M-44s may not be placed within 600 feet of a home unless affected landowners give written permission, the buffer from public roads and paths grew to 300 feet, and two warning signs must stand within 15 feet of each device.
Those changes made accidental contact by hikers and pets less likely near roads and homes, but they did not satisfy groups who want the devices banned outright. Their argument is that buffers protect people on paths, not wildlife or dogs that roam freely across open land.
What this means for hikers, dog owners and landowners
M-44s are still legal in several western states, so it is worth knowing what to look for if you walk in grazing country:
- Read posted signs. Warning signs are required near devices. If you see one, keep dogs leashed and stay on the trail.
- Do not touch unfamiliar stakes or pipes sticking out of the ground, especially if they have a fuzzy or scented top.
- If a person or pet is exposed, call emergency services or a vet immediately and tell them cyanide may be involved. Treatment is time-critical and must come from professionals.
- Landowners who share a boundary with grazing allotments can ask the relevant state agency or Wildlife Services office whether devices are in use nearby.
The broader question, whether lethal predator control on public land is worth its side effects, is not settled. Non-lethal tools such as guard dogs, fencing, lights and range riders are increasingly used, and the debate over M-44s is one part of a long argument about how ranching and wildlife share the American West.
Sources: Center for Biological Diversity, August 2019; High Country News: cyanide bomb use reauthorized; Western Livestock Journal, December 2019; Endangered Species Coalition, March 2022; East Idaho News, November 2018.
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