Right, Tannerite is legal (binary explosive, which is somehow technically different), but not for the purpose of harming animals, which is what happened in this case. Under Texas law, this would be illegal and constitute torture of the animals since the hunters knowingly set off the tannerite in close proximity to the animals which by design would cause unnecessary pain or suffering because of proximity to the detonation. That would be under 42.09(1). Most, if not all other states have similar laws.