(CNN) The US Environmental Protection Agency has begun reauthorizing "cyanide bombs" used as chemical traps to kill predatory animals, despite backlash from environmental groups.

The EPA released its Interim Registration Review Decision from June , announcing that it is moving forward with the reauthorization of M-44s, chemical traps filled with sodium cyanide

The EPA received over 20,000 letters about the move, it says, but the vast majority did not support the continued registration of the devices.

The devices are used to protect livestock and protected species from predators like coyotes, foxes and feral dogs. But critics argue that they can harm people and non-predatory animals that may stumble upon them.

That's what happened in 2017, when a cyanide trap laid by the US Department of Agriculture killed a 14-year-old's dog in Idaho

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