Update, August 16th 2019: The EPA has reneged on its decision to lift the temporary ban in response to the resulting backlash.

EPA Administrator Andrew Wheeler announced his withdrawal of the decision in a statement, saying: "This issue warrants further analysis and additional discussions by EPA with the registrants of this predacide...I look forward to continuing this dialogue to ensure U.S. livestock remain well-protected from dangerous predators while simultaneously minimizing off-target impacts on both humans and non-predatory animals."

The US federal government has given "cyanide bombs" as a method to kill wild animals the thumbs-up, despite strong opposition from environmentalists and wildlife advocates.

Cyanide bombs, officially known as M-44s, are spring-loaded traps filled with sodium cyanide – a poison designed to kill pests, including foxes, coyotes, and wild pigs. The idea is to entice the animal in with bait, then spray their mouths with toxic chemicals. 

The problem is, "pests" are not the only animals that have been caught in the trap. Not only does it risk killing wild animals that are not considered pests, particularly threatened or endangered ones, but also pets and people who inadvertently get in the way.

The US Fish and Wildlife Service (FWS) revealed more than 1.5 million animals were disposed of by their agents in 2018, 6,500 or so by M-44s. Animals killed included wolves, black bears, and owls.

In 2017, three pet dogs were killed by a "cyanide bomb" and a teen from Idaho was temporarily blinded. His parents successfully sued the government for $150,000 the following year.

The FWS has employed M-44s since the 1960s but were forced to reconsider their use after a lawsuit was brought up by four conservation and wildlife groups in 2018.

Idaho and Colorado have both previously banned the traps, and Oregon signed the ban on using them into law in May. 

On Tuesday, the Environmental Protection Agency (EPA) reauthorized their use, allowing it to continue on an interim basis and with certain provisos. New restrictions mean that M-44s can no longer be placed within 100 feet (30 meters) of a public road or path. (Previously, the rules stated 50 feet/15 meters.) Now, warning signs must be visible from 15 feet (4.5 meters) – not 25 feet (7.6 meters).

The EPA sided with ranchers and agriculturists, stating that M-44s will prevent predators attacking livestock, while a ban would lose farmers money. But opponents of the poison device have criticized the decision, calling the bombs "indiscriminate killers".

"Cyanide traps are indiscriminate killers that can’t be used safely by anyone, anywhere," Collette Adkins, carnivore conservation director at the Center for Biological Diversity, said in a statement.

"We’re fighting for a permanent nationwide ban, which is the only way to protect people, pets and imperiled wildlife from this poison."

The Center for Biological Diversity found that more than 99 percent of comments received by the EPA in relation to the M-44 reauthorization supported a ban.