How to Hide an Empire: A History of the Greater United States

by Daniel Immerwahr

was an important post. Though the Chemical Warfare Service ran tests on animals—goats were a favorite—it insisted that all gases and equipment be ultimately tested on humans. Those humans were soldiers, recruited with modest inducements such as extra leave time or appeals to patriotism. They participated in three types of tests. In the drop test, liquid was applied to their skin. In the field test, planes sprayed them from overhead. In the chamber test, sometimes called the “man-break test,” participants were locked in gas chambers and gassed until they faltered. Those inhaling gas usually had protective gear, but the tests often pushed past the point where that gear functioned. In some cases, that meant days in gas chambers or in the jungle with gas bombs dropping overhead. Participants seeking to leave midway through were threatened with court-martial. During the war, the military tested its gases and gear on more than sixty thousand of its own men.