These experiments are not only controversial because of the animal abuse involved. While they may appear to serve a defensive purpose, vaccine research may be intended to find ways to allow the use of chemical agents in combat or to circumvent defenses, according to some critics. Chemical weapons are widely tested on rats, primates, pigs, rabbits, and other animals. Poison gases can damage the lungs, nerves, skin, and eyes, and cause a slow and painful death. Such tests are as misleading as they are cruel.
Animals often respond to chemical agents and antidotes differently than humans.
A rat's respiratory system differs greatly from that of a human, and rats are more susceptible to toxins because they are unable to vomit. Mice have a genetic tendency to develop lung tumors, rendering much of the research on physiological effects of exposure invalid. Mustard gas, first used in World War I, continues to be a favorite agent for Department of Defense animal experimenters. Yet good treatments are already available and are easy to use. Preventive drugs, such as benactyzine, oximes, aprophen, and physostigmine, are also commonly used.