Don't know if this stuff is still available but it's called Calcium Carbide and is a really good gopher getter (works on moles too). EPA or homeland security may have banned it. This stuff is what the miners used to fuel their lamps while in the mines. The way to use it is uncover the "run" (hole) and spoon in a couple of tablespoons of the Calcium Carbide. Place a piece of cardboard over the hole to keep it from caving in. Cover the mound up and pour on about a quart of water. When the water hits the Carbide it generates Acetylene gas which spreads throughout the entire run and kills everything. Doesn't hurt the dirt. Good luck.