How Do Chemical Weapons Smell?

Obviously, this isn't one of those questions you go out and answer based on personal observation and experimentation. However, the fragrance of chemical agents is known from their testing and use. Many chemical weapons are colorless and odorless in their pure form. The nerve agents sometimes carry a faint fruity aroma. Certain blistering agents, like mustard gas and phosgene, smell weedy or floral. Lewisite smells of geraniums. Soman reputedly smells like Vicks VapoRub™. Many people are aware that the cyanide in Zyklon B has a bitter almond odor, but you might be surprised to learn not everyone has the smell receptor to detect it.

When I first published this blog entry, I got a question almost right away from a reader asking if the odors are just the closest analogy a person exposed to the agent could come up with (you know... like saying a new food 'tastes like chicken' because you don't have anything closer to compare to it). From personal experience, I can say cyanide smells just like almond extract or Amaretto™ and hydrogen sulfide smells just like rotten eggs (I have the local paper mill and some leftoever Easter eggs to thank for that experience). Some of the other agents may have distinct odors, all their own. Smell is personal, determined in part by heredity, so two people may perceive an odor differently, which is part of why some people say Soman smells like rotting fruit while others detect a camphor odor.

Chemical Weapons - What You Need to Know | Ricin & RCA
Photo Credit: U.S. Army. Chemical Weapons Symbol.