All elective officers, department heads, boards, commissions and/or other public officials of all state, county or municipal governments and departments and all political subdivisions thereof, who may be authorized to select or hire employees, are hereby required to strictly observe this preference for veterans and disabled veterans when implementing a reduction in force, filling vacancies or selecting new employees, provided that this chapter shall not apply to key employee positions. This preference shall be granted without regard to political affiliation or endorsements to veterans and disabled veterans who are qualified for the position or positions to be filled. In the event of an emergency which may endanger the health, safety, and public welfare, the provisions of this chapter may be dispensed with temporarily, but in no event shall persons who were employed to meet such emergencies be permitted to work for a period of time exceeding ninety (90) days, except such employees who meet all the requirements provided for in the chapter.