Any member permanently incapacitated for the performance of duty shall be retired for disability regardless of age if, and only if:
(a) The member’s incapacity is a result of injury or disease arising out of and in the course of the member’s employment, and such employment contributes substantially to such incapacity, or
(b) The member has completed five years of service, and
(c) The member has not waived retirement in respect to the particular incapacity or aggravation thereof as provided by Section 31009.
The amendments to this section enacted during the 1979–80 Regular Session of the Legislature shall be applicable to all applicants for disability retirement on or after the effective date of such amendments.