In 1980, out of 5,324 USA servicemen removed from nuclear weapons work, the largest proportion (1,726) went because of drug abuse. A 1982 Pentagon survey showed that 31.4% of American servicemen in Europe admitted using drugs including marijuana, cocaine and LSD in 1981. Among young enlisted men the figure exceeded 40%. Some scientists believe the drug-taking increases the risk of a serious incident, maybe nuclear, happening by mistake.