For whatever reason, the internet seems to love This One Simple Trick: using bug spray –especially wasp spray– for self defense. It shoots 20 feet, and contains a neurotoxin that is immediately effective, so if that’s all you know about it, one can imagine where the appeal lies. The issue here is that the neurotoxin in question is usually one of a group of chemicals called pyrethrins, which are commonly found in other insecticides like Fly-Die, which is intended to be sprayed directly onto livestock and pets.
Pyrethrins and pyrethroids are absolutely neurotoxic, but in commercially available formulations are not concentrated enough to affect most mammals over 5lb. For example, the average yellow jacket weighs 0.04-0.08g while the average American human weighs 80,000g. Similarly, the volume of pyrethrin-based insecticide necessary to paralyze or kill a human is going to be tens of thousands of times larger vs a wasp. To put it another way, the volume of plain old water you drink on any random day is enough to kill dozens of these insects, were they somehow forced to ingest it. Dose is what makes a poison, and wasp spray is simply not going to deliver enough of it to a human being to be effective as a self-defense tool.
As the article linked above illustrates, this mental exercise plays out the same way in real life. A man who, for whatever reason, decided today was the day to get froggy with his neighbor bet his life on wasp spray, likely because he’d heard about it online or from a friend, and lost. His intended victim was not only not killed by a shot of Raid to the face, he was capable of lethal force, drawing and firing a concealed handgun that would later kill his pyrethrin-wielding attacker.
Lastly, if you look at the label on any can of wasp spray, it plainly states that using it in a manner inconsistent with the label is a federal crime, and that the primary danger to humans is “eye irritation”. While it’s unlikely that an actual prosecution would follow, it’s not going to read well to a jury that you chose a self-defense method that is explicitly unlawful. Choose something designed to stop humans, like a quality pepper spray, if you are looking for something other than a gun or knife. It has a much greater chance of actually stopping an attack, and doesn’t require breaking the law to use on an attacker.
