ABSTRACT
As the Americans began incorporating CS into the broader scope of their combat operational plans, they quickly realized its fundamental properties – it was essentially non-lethal; it was effective at low concentrations; the cloud rapidly diffused, spread out over a large area and penetrated into hardened defensive fortifications; and, if delivered properly, the contamination could persist for extended periods – made it the best weapon for a number of tactical situations. Sometimes the decisive advantage obtained by using gas became obvious when a new weapon system was introduced onto the battlefield; at other times it was the result of careful analysis of past combat operations or the suggestion from a combat soldier in the field. Still other times it was pure chance, a discovery made through the impulsive actions of soldiers trying to get out of a tight situation with nothing to lose. Ironically, the situation that reopened the door for the United States to use riot-control agents in combat and the one these agents were uniquely suited for, that is to say incapacitation of soldiers hiding among civilians, was soon only a minor consideration for American troops. While Washington continued to maintain throughout the war that tear gas was routinely used for this purpose, field commanders told MACV in the spring of 1968 this was in fact not the case. These officers said their units rarely used CS specifically to save civilian lives and doubted it would ever be used routinely for this tactical purpose. The commanders justified their conclusion by pointing out civilians quickly evacuated a battlefield to prevent becoming hostages. While their justification was not entirely accurate, their conclusion was, and tear gas was only rarely used specifically to segregate combatants from civilian hostages. However, there were five other key niche areas where tear gas was universally regarded to be the key asset to resolve tricky situations. The first four of these were: breaking contact,
flushing an enemy out of hiding, denying the guerrillas access to either key terrain or critical resources, and search-and-rescue operations.1
