It ' s important to understand that these weapons are not nonlethal . These weapons are marketed as less than lethal or nonlethal to indicate that when used properly by qualified and trained specialists , the probability of casualty is diminished but not eliminated . It is also important to point out that the use of stun grenades by police forces is not normal , and should not be accepted so openly . These weapons were initially reserved for combat operations and peacekeeping operations which operate under context of acceptable loss . It ' s only very recently that they ' ve been deployed on civilian demonstrators especially in the US . Tear gas canisters are chemical explosives , they are more controlled but are still markedly lethal if not used correctly . There is a real threat of asphyxiation , which is why riot police grab teams are trained extensively in their use . Introducing low pressure explosives with minimal training and used so liberally in a noncontrolled environment is dangerous , and increases the risk of casualty . It is dangerous to speak so confidently about topics that people know little to nothing about . These are weapons designed to incapacitate and control , and you the average American , not necessarily you to avoid assumption do not know enough to make judgements supporting its use or to claim that its use is not responsible for civilian casualties which continue to increase in number .