CHEYENNE, Wyo. (AP) — A coalition of environmental groups has petitioned the U.S. Fish and Wildlife Service asking for a Wyoming statewide ban on cyanide traps being used to kill coyotes.

The animal rights and conservation groups petitioned Tuesday amid recent incidents where dogs in Wyoming and Idaho were killed by the traps.

A coalition of some of the same groups filed a similar petition in March in Idaho, which prompted a statewide ban on private, state and federal land.

Trappers in Wyoming began using the trap, M-44s, in 1975. The traps kill by injecting sodium cyanide powder into an animal's mouth that releases hydrogen cyanide gas when mixed with saliva. Because the poison is metabolized instantly, M-44s are seen as a less hazardous way to kill predators than poisons.