How Do Chemical Weapons Smell?

The molecules used as chemical weapons are often small. Some have no odor, but others have a characteristic scent that warns of their presence.
The molecules used as chemical weapons are often small. Some have no odor, but others have a characteristic scent that warns of their presence. INDIGO MOLECULAR IMAGES / Getty Images

You may have a mental image of a chemical agent as some greenish vapor with a pungent, unpleasant smell. Are you surprised to learn most chemical agents are colorless and odorless? Many have characteristic odors, but some actually smell nice.

Chemical Agent Odors

Many blister agents smell a bit like plants. Other agents may have pungent odors, yet most chemical weapons have no scent at all. Here's a list of some chemical agents and their... bouquets:

  • Sulfur Mustard: includes mustard gas, usually odorless and colorless in pure form but yellowish-brown with an odor reminiscent of the mustard plant, garlic, or horseradish when used in warfare
  • Chlorine Gas: pale greenish gas with a suffocating, unpleasant odor, similar to chlorine bleach
  • 3-quinuclidinyl benzilate (QNB or NATO BZ or Iraqi Agent 15): odorless incapacitating agent
  • Lewisite: WWI blister agent that smells strongly of geraniums
  • Phosgene Oxime: blister agent with an irritating smell, though somewhat of mown hay or cut green corn
  • Sarin: extremely toxic odorless nerve agent
  • VX: probably the most toxic nerve agent, odorless
  • Soman: nerve gas that smells like Vicks VapoRub or rotting fruit, depending on who you ask
  • Tabun: highly toxic nerve agent with a faint fruity smell, though odorless when pure
  • Zyklon B: hydrogen cyanide-containing blood agent, famous for its use in Nazi death camps, which has a bitter almond odor (not everyone has the ability to smell it, though)
  • Hydrogen Sulfide: blood agent that smells of rotten eggs
  • Adamsite or DM: odorless riot control agent that causes vomiting and sneezing
  • CS Gas: tear gas, odorless