The monthly allowance provided by Section 21624 shall be paid on account of patrol and state safety members retired for nonindustrial disability with effective dates of retirement prior to April 1, 1972, and who did not at retirement elect optional settlement 2 or 3 or an optional settlement involving life contingency under optional settlement 4. Upon receipt of a written application by the board, the benefits provided by this section shall also be payable to eligible survivors of retired members who are not receiving a monthly allowance on account of service as a patrol or state safety member if the retired member was alive and receiving a monthly allowance on June 30, 1974. The benefits shall be subject to the same eligibility and termination provisions that apply to members at retirement and shall be paid only for the period of time commencing on the first of the month following receipt by the board of the application for those benefits.