Homosexuality is incompatible with military service. The presence in the military environment of persons who engage in homosexual conduct or who, by their statements, demonstrate a propensity to engage in homosexual conduct, seriously impairs the accomplishment of the military mission. The presence of such members adversely affects the ability of the armed forces to maintain discipline, good order, and morale; to foster mutual trust and confidence among service members; to ensure the integrity of the system of rank and command; to facilitate assignment and worldwide deployment of service members who frequently must live and work in close conditions affording minimal privacy; to recruit and retain members of the armed forces; to maintain the public acceptability of military service; and to prevent breaches of security.
DOD Directive 1332.14 (Enlisted Administrative Separations), January, 1981):

Example

USS Iowa turret explosion - Wikipedia, the free encyclopedia
USS Iowa turret explosion