(i) credited service which was rendered as a member of the uniformed force of the New York city department of sanitation; and

(ii) credited service which was rendered in another uniformed force (as defined in paragraph seven of this subdivision) immediately prior to becoming a member of the uniformed force of the New York city department of sanitation; and

(iii) credited service which was rendered in the uniformed force of the New York city police department or the uniformed force of the New York city fire department immediately prior to becoming a member of the uniformed force of the New York city department of sanitation and which was transferred to the New York city employees' retirement system pursuant to section forty-three of this chapter. 7. "Another uniformed force" shall mean (i) the uniformed transit police force maintained by the New York city transit authority and by its predecessor, the board of transportation; or (ii) all of the positions in the New York city housing authority which are included in the housing police service of the classification of the New York city department of personnel; or (iii) the uniformed force of the New York city department of correction. 8. "Minimum period" shall mean the minimum period of twenty years of allowable service in the uniformed sanitation force that is required in order for a participant in the twenty-year retirement program to be eligible for early service retirement pursuant to paragraph one of subdivision c of this section. 9. "Final compensation" shall mean the average compensation earned by a member during any five consecutive years which provide the highest average compensation. Where the period used to determine final compensation is the period which immediately precedes the date of retirement, any month or months (not in excess of twelve) which would otherwise be included in computing final compensation but during which the member was on authorized leave of absence at partial pay or without pay shall be excluded from the computation of final compensation and the month or an equal number of months immediately preceding such period shall be substituted in lieu thereof. 10. "Discontinued member" shall mean a participant in the twenty-year retirement program who, while he or she was a New York city sanitation member, discontinued service in the uniformed force of the New York city department of sanitation and has a right to a deferred vested benefit under subdivision d of this section. 11. "Administrative code" shall mean the administrative code of the city of New York. b. Participation in twenty-year retirement program. 1. Subject to the provisions of paragraph six of this subdivision, any person who is a New York city sanitation member on the enactment date of the twenty-year retirement program and who, as such a sanitation member or otherwise, last became subject to the provisions of this article prior to such enactment date, may elect to become a participant in the twenty-year retirement program by filing, within ninety days after the enactment date of the twenty-year retirement program, a duly executed application for such participation with the retirement system of which such person is a member, provided he or she is such a sanitation member on the date such application is filed. 2. Subject to the provisions of paragraph six of this subdivision, any person who becomes a New York city sanitation member after the enactment date of the twenty-year retirement program and who, as such a sanitation member or otherwise, last became subject to the provisions of this article prior to such enactment date, may elect to become a participant in the twenty-year retirement program by filing, within ninety days after becoming such a sanitation member, a duly executed application for such participation with the retirement system of which such person is a member, provided he or she is such a sanitation member on the date such application is filed. 3. Any election to be a participant in the twenty-year retirement program shall be irrevocable. 4. Each New York city sanitation member who becomes subject to the provisions of this article on or after the enactment date of the twenty-year retirement program shall become a participant in the twenty-year retirement program on the date he or she becomes such a sanitation member. 5. Where any participant in the twenty-year retirement program shall cease to hold a position in the uniformed force of the New York city department of sanitation, he or she shall cease to be such a participant and, during any period in which such person does not hold such a uniformed sanitation position, he or she shall not be a participant in the twenty-year retirement program and shall not be eligible for the benefits of subdivision c of this section. 6. Where any participant in the twenty-year retirement program terminates service in the uniformed force of the New York city department of sanitation and returns to such service as a New York city sanitation member at a later date, he or she shall again become such a participant on that date. c. Service retirement benefits. 1. A participant in the twenty-year retirement program:

(i) who has completed twenty or more years of allowable service in the uniformed sanitation force; and

(ii) who has paid, before the effective date of retirement, all additional member contributions and interest (if any) required by subdivision e of this section; and

(iii) who files with the retirement system of which he or she is a member an application for service retirement setting forth at what time he or she desires to be retired; and

(iv) who shall be a participant in the twenty-year retirement program at the time so specified for his or her retirement; shall be retired pursuant to the provisions of this section affording early service retirement. 2. (i) Notwithstanding any other provision of law to the contrary, the early service retirement benefit for participants in the twenty-year retirement program who retire pursuant to paragraph one of this subdivision shall be a pension consisting of:

(A) an amount, on account of the required minimum period of service, equal to one-half of his or her final average salary; plus

(B) an amount for each additional year of allowable service in the uniformed sanitation force, or fraction thereof, beyond such required minimum period of service equal to one and one-half percent of his or her final compensation; plus

(C) an amount for each year, or fraction thereof, of credited service other than allowable service in the uniformed sanitation force equal to one percent of his or her final compensation.

(ii) The maximum pension computed without optional modification payable pursuant to subparagraph (i) of this paragraph shall equal that payable upon completion of thirty years of service. d. Vesting. 1. A participant in the twenty-year retirement program who:

(i) discontinues city-service and service as a member of the uniformed force of the New York city department of sanitation, other than by death or retirement; and

(ii) prior to such discontinuance, completed five but less than twenty years of allowable service in the uniformed sanitation force; and

(iii) has paid, prior to such discontinuance, all additional member contributions and interest (if any) required by subdivision e of this section; and

(iv) does not withdraw in whole or in part his or her accumulated member contributions pursuant to section six hundred thirteen of this article unless such participant thereafter returns to public service and repays the amounts so withdrawn, together with interest, pursuant to such section six hundred thirteen of this article; shall be entitled to receive a deferred vested benefit as provided in this subdivision. 2. (i) Upon such discontinuance under the conditions and in compliance with the provisions of paragraph one of this subdivision, such deferred vested benefit shall vest automatically.

(ii) Such vested benefit shall become payable on the earliest date on which such discontinued member could have retired for service if such discontinuance had not occurred. 3. Such deferred vested benefit shall be a pension consisting of:

(i) an amount equal to two and one-half percent of such discontinued member's final average salary, multiplied by the number of years of allowable service in the uniformed sanitation force credited to such discontinued member on the date of such discontinuance; plus

(ii) an amount for each year, or fraction thereof, of credited service other than allowable service in the uniformed sanitation force equal to one percent of his or her final compensation. e. Additional member contributions. 1. In addition to the member contributions required by section six hundred thirteen of this article, each participant in the twenty-year retirement program shall contribute to the retirement system of which he or she is a member (subject to the applicable provisions of section 13-125.1 of the administrative code) an additional five and thirty-five one-hundredths percent of his or her compensation earned from all allowable service in the uniformed sanitation force rendered on and after the starting date of the twenty-year retirement program. A participant in the twenty-year retirement program shall contribute additional member contributions only until he or she has twenty years of allowable service in the uniformed sanitation force. 2. (i) Commencing with the payroll period which begins on the starting date of the twenty-year retirement program (for a person who elects to become a participant prior to such starting date), or commencing with the first full payroll period after a person becomes such a participant (for a person who becomes a participant on or after such starting date), additional member contributions at the rate specified in paragraph one of this subdivision shall be deducted (subject to the applicable provisions of section 13-125.1 of the administrative code) from the compensation of such participant on each and every payroll of such participant for each and every payroll period.

(ii) (A) Where any additional member contributions required by paragraph one of this subdivision are not paid by deductions from a participant's compensation pursuant to subparagraph (i) of this paragraph because such contributions are for service rendered in a payroll period prior to the actual commencement of deductions pursuant to such subparagraph (i), such amounts shall be paid by deductions from the compensation of such participant pursuant to item (B) of this subparagraph.

(B) Commencing with the payroll period in which deductions of additional member contributions from a participant's compensation are begun pursuant to subparagraph (i) of this paragraph, in addition to such deductions required by such subparagraph (i), there shall be another deduction of additional member contributions made from the compensation of such participant at the rate specified in paragraph one of this subdivision (subject to the applicable provisions of section 13-125.1 of the administrative code) on each and every payroll period until the total amount of unpaid additional member contributions described in item (A) of this subparagraph, if any, has been paid by deductions from compensation pursuant to this subparagraph. 3. (i)(A) Where any additional member contributions required by paragraph one of this subdivision are not paid by deductions from a participant's compensation pursuant to paragraph two of this subdivision, that participant shall be charged with a contribution deficiency consisting of such unpaid amounts, together with such interest thereon as required by subparagraph (ii) of this paragraph, compounded annually.

(B) Except as provided in subparagraph (ii) of this paragraph, no participant shall be required to pay any interest on his or her contribution deficiency.

(ii)(A) Should any person who, pursuant to paragraph eight of this subdivision, has withdrawn any additional member contributions (and any interest paid thereon) again become a participant in the twenty-year retirement program pursuant to paragraph six of subdivision b of this section, an appropriate amount shall be included in such participant's contribution deficiency (including interest thereon as calculated pursuant to item (B) of this subparagraph) as if such additional contributions had never been made.

(B) Interest on the amounts of additional member contributions included in a participant's contribution deficiency pursuant to item (A) of this subparagraph shall be calculated as if such additional member contributions had never been paid by a participant, and such interest shall accrue from the end of the payroll period to which an amount of additional member contributions is attributable, until such amount is paid to the retirement system.

(C) The rate of interest to be applied to each such amount during the period for which interest accrues on that amount shall be five percent per annum, compounded annually. 4. A participant, while he or she is a New York city sanitation member, shall pay the total amount of his or her contribution deficiency to the retirement system in accordance with payment procedures which shall be established by the executive director of the retirement system, and approved by the board of trustees of the retirement system. 5. Where a contribution deficiency chargeable to a participant pursuant to paragraph three of this subdivision has not been paid in full before the effective date of retirement, that participant shall not be eligible to retire pursuant to subdivision c of this section. 6. Where a contribution deficiency chargeable to a participant pursuant to paragraph three of this subdivision has not been paid in full before the date of discontinuance of service, that participant shall not be entitled to a deferred vested benefit pursuant to subdivision d of this section. 7. Where a participant has not paid in full any contribution deficiency chargeable to him or her pursuant to paragraph three of this subdivision, and a benefit, other than a refund of member contributions pursuant to section six hundred thirteen of this article or a refund of additional member contributions pursuant to paragraph eight of this subdivision, becomes payable under this article to the participant or to his or her designated beneficiary or estate, the actuarial equivalent of any such unpaid amount shall be deducted from the benefit otherwise payable. 8. (i) Such additional member contributions (and any interest thereon) shall be paid into the contingent reserve fund of the retirement system of which the participant is a member and shall not for any purpose be deemed to be member contributions or accumulated contributions of a member under section six hundred thirteen of this article or otherwise while he or she is a participant in the twenty-year retirement program or otherwise, except that, a surplus of such additional member contributions that are paid into the retirement system's contingent reserve fund may be used for the sole purpose of offsetting a deficit of basic member contributions.

(ii) (A) Should a participant in the twenty-year retirement program who has rendered less than fifteen years of allowable service in the uniformed sanitation force cease to hold a position in the uniformed force of the New York city department of sanitation for any reason whatsoever, his or her accumulated additional member contributions made pursuant to this subdivision (together with any interest thereon paid to the retirement system) may be withdrawn by him or her pursuant to procedures promulgated in regulations of the board of trustees of the retirement system, together with interest thereon at the rate of five percent per annum, compounded annually.

(B) Upon the death of a participant in the twenty-year retirement program, there shall be paid to such person as he or she has nominated or shall nominate to receive his or her accumulated member contributions by written designation duly executed and filed with the retirement system during the lifetime of such participant, or, to his or her estate if no such person is nominated, his or her accumulated additional member contributions made pursuant to this subdivision (including any interest thereon paid to the retirement system), together with interest thereon at the rate of five percent per annum, compounded annually.

(iii) Except as provided in subparagraph (ii) of this paragraph, no member while he or she is a participant or otherwise, shall have a right to withdraw such additional member contributions or an interest thereon from the retirement system. 9. No member of a public retirement system shall be permitted to borrow any portion of the additional member contributions (including any interest paid thereon by the participant) which are subject to this subdivision.