Nerve gas

Nerve gases are clear and colorless, and they can be odorless or have a slight, sweetish smell. They enter the body through the air or on contact with the skin. Nerve gases can be released using spray tanks, bombs, missiles or land mines. Nerve agents have more density than air, making them dangerous to people in low areas.

Nerve gases attack the nervous system of the body by interrupting the breakdown of neurotransmitters that signal muscles to contract. The gases inactivate the enzyme cholinesterase, which normally controls the transmission of nerve impulses. The impulses continue uncontrolled and cause respiratory breakdown.

Nerve gases generally cause death by asphyxiation. The symptoms preceding this include blurred vision, runny nose, tightness in the chest and constriction of the pupils. The victim will next have difficulty breathing, and will experience nausea and drooling. As the victim continues to lose control of his bodily functions, he will involuntarily vomit, defecate and urinate. This phase is followed by twitching and jerking, and the victim will lapse into a coma and suffocate as a consequence of convulsive spasms.

Nazi Germany developed nerve gases during World War II. As chemical weapons, they are classified as weapons of mass destruction by the United Nations. VX is the most deadly nerve gas and Tabun is the least deadly (although still very hazardous).