Section 89. If a member of the police or fire force, or a forest warden, of a city or town is killed, or dies from injuries received, or dies as a natural and proximate result of undergoing a hazard peculiar to his employment, while in the performance of his duty, and it shall be proved to the satisfaction of the appropriate public authority as hereinafter defined that such death was the natural and proximate result of an accident occurring, or of undergoing a hazard peculiar to his employment, while he was acting in the performance and within the scope of his duty, and a majority of the members of a board consisting of two physicians designated by the public authority hereinafter defined, and one physician to be designated by the commissioner of public health, who shall serve as chairman of the board, shall certify to the appropriate public authority that the death was the natural and proximate result of the said injury or hazard, there shall, except as hereinafter provided, be paid out of the treasury of such body politic and corporate, to the following dependents of such deceased person the following annuities: To the widow, so long as she remains unmarried, an annuity of fifteen hundred dollars a year, increased by not exceeding three hundred and twelve dollars for each child of such deceased person during such time as such child is under the age of eighteen or over said age and physically or mentally incapacitated from earning; and, if there is any such child and no widow or the widow later dies, such an annuity as would have been payable to the widow had there been one or had she lived, to or for the benefit of such child, or of such children in equal shares, during the time aforesaid; and, if there is any such child and the widow remarries, in lieu of the aforesaid annuity to her, an annuity not exceeding five hundred and twenty dollars to or for the benefit of each such child during the time aforesaid; and, if there is no widow and no such child, an annuity not exceeding one thousand dollars to or for the benefit of the father or mother of the deceased, or to or for the benefit of an unmarried or widowed sister of the deceased with whom he was living at the time of his death, if such father, mother or sister was dependent upon him for support at the time of his death, during such time as such beneficiary is unable to support himself or herself and does not marry. The members of said board to be designated by the public authority and the commissioner of public health, as aforesaid, shall be so designated within thirty days after the filing of an application for an annuity hereunder, and said members shall make their report within sixty days after their appointment. The total amount of all such annuities shall not, except as hereinafter provided, exceed the annual rate of compensation received by such deceased person at the date of his death if such annual rate was more than fifteen hundred dollars. If such deceased person was a reserve, intermittent or special policeman or a reserve or call fireman of a city or town, and, at the time he was killed or at the time he received the injuries or underwent the hazard resulting in his death, was performing duty to which he was assigned or called as such policeman or fireman, the total amount of all such annuities shall not exceed the annual rate of compensation payable to a regular or permanent member of the police or fire force thereof, as the case may be, for the first year of service therein, if such annual rate was more than fifteen hundred dollars, and if there are no regular or permanent members of the police or fire force thereof, as the case may be, said total amount shall not exceed the sum of twelve hundred dollars. The amount of any such annuity shall from time to time be determined within the limits aforesaid by the appropriate public authority as hereinafter defined.

In case the deceased was a member of a contributory retirement system for public employees, the benefits provided under this section shall be in the alternative for the benefits, if any, provided by such retirement system for dependent widows and children or for dependent fathers or mothers; and the widow, or if there is no widow, the legal representative of the children entitled thereto, if any, otherwise the father or mother in the order named, shall elect which benefits shall be granted. Such election shall be made in writing and shall be filed with the retirement board in charge of the system of which the deceased was a member and shall not be subject to change or revocation after the first payment of any benefit thereunder.

In the case of a city employee, within thirty days after receiving a medical report on such employee from the medical board the mayor shall file said report with or without recommendations to the city council, and they shall act thereon within sixty days.

The words ''appropriate public authority'', as used in this section, shall mean, as to the commonwealth, the state board of retirement; as to Suffolk county, the Boston retirement board; as to other counties and cities or towns, the appropriate retirement board, established under section twenty, having jurisdiction in the governmental unit in which person was employed, or, if there is no such board in the case of a town, the selectmen.

The provisions of this section shall apply to deaths resulting from injuries received, occurring on or after January first, nineteen hundred and thirty in the case of policemen and firemen and members of the office of public safety and inspections of the division of professional licensure and the division of inspection of the department of fire services doing police duty, occurring on or after August twenty-fifth, nineteen hundred and thirty-two in the case of inspectors or examiners of the registry of motor vehicles in the department of highways, occurring on or after September twenty-fifth, nineteen hundred and thirty-four in the case of forest wardens of cities or towns, and occurring on or after January first, nineteen hundred and thirty-four in the case of inspectors of the department of labor and workforce development and of prison officers, and occurring on or after January first, nineteen hundred and thirty-five, in the case of said technical employees, and to deaths resulting from hazards undergone, occurring on or after January first, nineteen hundred and thirty-five, in the case of policemen, firemen, uniformed members of the department of state police, forest wardens of cities or towns, inspectors of the department of labor and workforce development and prison officers, or occurring on or after January first, nineteen hundred and thirty-six, in the case of said technical employees, irrespective of the time of receiving the injuries or undergoing the hazards resulting in such death; provided, that nothing contained in this section shall affect any annuity lawfully granted under the provisions thereof as previously from time to time in effect.