From the article: > ...agents like mustard gas, which have a characteristic odor, tend to dull a victim’s sense of smell “after only a few breaths so that the

From the article: > ...agents like mustard gas, which have a characteristic odor, tend to dull a victim’s sense of smell “after only a few breaths so that the smell can no longer be distinguished.” In addition, the implementing body of the Chemical Weapons Convention states, respiratory damage can occur in the presence of even tiny, unsmellable concentrations of the agent.