The Environmental Protection Agency will allow the use of what critics call "cyanide bombs" to help farmers protect livestock from wild animals, angering environmental groups that say they aren't safe.

This week, the agency reauthorized use of M-44s in an interim decision posted to the Federal Register as a part of its ongoing review of the traps, which contain sodium cyanide. Its approval comes after a public comment period that garnered thousands of objections to the use of the devices.

Commenters expressed concerns about killing non-target wildlife and introducing the poison to residential areas. They also said that method, which involves luring predators like coyotes with bait to a device that sprays sodium cyanide into their mouths, is inhumane.

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To address some of these concerns, the EPA issued new restrictions for the use of the devices, which are typically deployed by a program within the Department of Agriculture called Wildlife Services. These include limiting placement of the devices to at least 100 feet outside of a public road or path and requiring visible warning signs within 15 feet of the trap.

But these restrictions aren't enough for the groups like The Center for Biological Diversity and WildEarth Guardians that previously petitioned the agency to stop all registered uses of the traps.

"Cyanide traps are indiscriminate killers that just can't be used safely," Collette Adkins, an attorney and biologist at the Center, said in a statement. "We're not fooled by the feds' ridiculous suggestion that bigger warning signs could somehow keep cyanide traps from hurting people, pets and imperiled wildlife. A permanent nationwide ban is the only answer."