(1) It shall be lawful to use any device which (a) is operated by the explosion of small amounts of gunpowder or other explosives, (b) is designed to discharge poison into the mouth of a wolf, coyote, fox, wildcat, or other predatory animals upon the grabbing or seizing of the bait attached to such device by such predatory animals, (c) does not discharge any ball, slug, shot, or other missile, and (d) does not endanger the life and limb of any human being or animal, other than a predatory animal, during the legal trapping season for fur-bearing animals. Such device may be used at any time by any agency of the commission or of the federal government or by persons having the written permission of the commission. Such lawful device when used shall be set not less than two hundred yards from any federal, state, or approved county highway and not less than one thousand yards from any school or from any inhabited dwelling without written permission of the resident of the dwelling. Such device shall not be used on another person's property without the written permission of the owner or operator.

(2) It shall be unlawful to use any of such devices unless the user shall, in addition to the other requirements of this section, post the land upon which the devices are emplaced with signs at least eighteen inches square and with block letters at least two inches in height and displaying the words DANGER, CYANIDE GUNS IN USE or with the official signs furnished for such a purpose by the United States Department of Agriculture. Such signs shall be placed at all entrances to the area where such devices are set, and a post shall be set by each such device displaying at least two of such signs in a manner so that such signs are plainly legible from all directions.