Pocatello's city council has voted to oppose the manufacture of cyanide bombs in town, sending a strong message about the danger of these devices.

Cyanide bombs, also called M-44s, are spring-loaded traps that spray cyanide into an animal's mouth, causing injury or death.

Dr. Mark Mansfield, a physician and M-44 opponent in Pocatello, knows the dangers firsthand. An M-44 detonated while Mansfield’s teenage son Canyon was walking his dog near their home in 2017. Canyon recovered but watched the dog, Kasey, die in front of him. Mansfield approached Pocatello's city council about the resolution against the devices and said he was speechless when it passed unanimously.

"It's a statement without doubt that this M-44 cyanide bomb and its manufacture, its assembly, its distribution to the entire United States, is unwelcomed in our city," Mansfield contended.

Since Canyon's injury, the Mansfields have become some of the leading voices working to ban M-44s. The federal government uses them to kill coyotes, foxes and other animals viewed as threats to livestock. The Pocatello Supply Depot, a warehouse owned by the federal government, makes and supplies most cyanide bombs in the U.S.

The city council's resolution comes after the Trump administration lifted a 2023 ban on cyanide bombs on Bureau of Land Management land in April.

Brooks Fahy, executive director of the nonprofit Predator Defense, has spent the past few decades fighting the use of the devices. Fahy said cyanide bombs have killed thousands of nontargeted animals, including endangered species and countless family dogs. While federal trappers are legally required to post warning signs, Fahy argued signage is a red herring and does not protect animals, adding there were no warning signs when Canyon and Kasey were poisoned.

"Children don't read warning signs, animals don't read warning signs, and what we've discovered through our field investigations over the last 35 years is at least half the time, they don't put up the warning signs because they don't want to make the public aware that these devices are even there," Fahy pointed out.

Fahy, Mansfield and other supporters said they will keep fighting to ban M-44s. They are also pushing Congress to pass legislation called Canyon's Law.

Mansfield explained it would make the ban permanent, so future presidential administrations would be unable to put other families in harm's way.

"As we know, Congress is pretty dysfunctional, and once they pass something, they rarely ever reverse it," Mansfield observed. "If we could get it passed, it'd be forever. Because I just think, who logically would ever bring back cyanide bombs onto public lands?"

The bill was introduced in the U.S. Senate last year. Fahy is not expecting action on it during this midterm election year but encouraged people to contact their senators and representatives to increase support for it.