Modern versions ... his technology to the U.S. military and its allies to combat the horrific gas attacks of World War I. “With a few slight modifications [the masks] will withstand chlorine ...

Wikimedia Commons Haldane, for his part, helped to work on the box respirator, the direct ancestor of the modern gas mask. The box respirator was ultimately designed by another scientist ...

in a gas mask drill. The experiments however, exposed troops to chemical weapons without such protection. Bettmann/CORBIS During World War II, the U.S. military conducted secret chemical weapons ...