As used in this chapter, unless the context clearly indicates otherwise:
ATTACK: Any attack or series of attacks by an enemy of the United States causing, or which may cause, substantial damage or injury to the civilian property or persons in the United States in any manner, by sabotage or by the use of bombs, missiles, shellfire, or atomic, radiological, chemical, bacteriological, or biological means or other weapons or processes.
DULY AUTHORIZED DEPUTY: A person who is presently authorized to perform all of the functions, exercise all of the powers and discharge all of the duties of an office in the event the office is vacant or at such times as it lacks administration due to the death, absence or disability of the incumbent officer.
EMERGENCY INTERIM SUCCESSOR: A person designated pursuant to this chapter for possible temporary succession to the powers and duties, but not the office, of a city officer in the event that such officer or any duly authorized deputy is unavailable to exercise the powers and discharge the duties of the office.
UNAVAILABLE: Either that a vacancy in office exists and there is no deputy authorized to exercise all of the powers and discharge the duties of the office, or that the lawful incumbent of the office (including any deputy exercising the powers and discharging the duties of an office because of a vacancy) and his duly authorized deputy are absent or unable, for physical, mental or legal reasons, to exercise the powers and discharge the duties of the office. (Prior code §1-69)