Guard AlaskaÂ® Bearspray Guard Alaska ultra hot pepper spray has proven so effective repelling bears, it is the only one registered with the EPA as a repellent for All Species of bear! It is absolutely the most effective and powerful bear defense spray available today. It is environmentally safe! Does not contain flammable or ozone depleting substances.This bear pepper spray elicits an intense burning sensation when it comes in contact with skin, causing pain receptors to send the same impulses as those generated by burning heat. It is a very effective defense because of the way it effects the mucous membranes of the eyes, nose and lungs. This spray immediately causes these tissues to swell and the result is a nearly total, yet temporary, loss of sight and severe restriction of breathing.