Any person entitled to receive a disability retirement benefit under article 3, as in effect immediately before October 1, 1989, may elect to be governed by this article instead of article 3 by making written application to the chief executive officer within 6 months of October 1, 1989.   [RR 1997, c. 2, §22 (COR); PL 2021, c. 548, §45 (REV).]