6. (1) Upon the written application by a member in service, by one acting in his behalf or by his employer, any member, under 55 years of age, who has had four or more years of creditable service may be retired on an ordinary disability retirement allowance; provided, that the medical board, after a medical examination of such member, shall certify that such member is mentally or physically incapacitated for the performance of his usual duty and of any other available duty in the department which his employer is willing to assign to him and that such incapacity is likely to be permanent and to such an extent that he should be retired.

(2) Upon retirement for ordinary disability, a member shall receive an ordinary disability retirement allowance which shall consist of:

(a) An annuity which shall be the actuarial equivalent of his aggregate contributions and

(b) A pension in the amount which, when added to the member’s annuity, will provide a total retirement allowance of 1 1/2 % of final compensation multiplied by his number of years of creditable service but in no event shall the total allowance be less than 40% of the member’s final compensation.

(3) Notwithstanding the provisions of subsection (2) of this section, a member who has more than 20 but less than 25 years of creditable service and who is required to retire upon application by the employer on or after the effective date of P.L.1999, c.428, shall receive an ordinary disability retirement allowance which shall consist of:

(a) An annuity which shall be the actuarial equivalent of the member’s aggregate contributions; and

(b) A pension in the amount which, when added to the member’s annuity, will provide a total retirement allowance of 50% of final compensation plus 3% of final compensation multiplied by the number of years of creditable service over 20 but not over 25.

(4) Upon the receipt of proper proofs of the death of a member who has retired on an ordinary disability retirement allowance, there shall be paid to such member’s beneficiary, an amount equal to 3 1/2 times the compensation upon which contributions by the member to the annuity savings fund were based in the last year of creditable service; provided, however, that if such death shall occur after the member shall have attained 55 years of age the amount payable shall equal 1/2 of such compensation instead of 3 1/2 times such compensation.

L.1944,c.255,s.6; amended 1953, c.266, s.2; 1964, c.241, s.3; 1967, c.250, s.6; 1971, c.175, s.3; 1989, c.204, s.2; 1999, c.428, s.3.