Section 9. Zoning ordinances or by-laws shall provide for specific types of uses which shall only be permitted in specified districts upon the issuance of a special permit. Special permits may be issued only for uses which are in harmony with the general purpose and intent of the ordinance or by-law, and shall be subject to general or specific provisions set forth therein; and such permits may also impose conditions, safeguards and limitations on time or use.

Zoning ordinances or by-laws may also provide for special permits authorizing increases in the permissible density of population or intensity of a particular use in a proposed development; provided that the petitioner or applicant shall, as a condition for the grant of said permit, provide certain open space, housing for persons of low or moderate income, traffic or pedestrian improvements, installation of solar energy systems, protection for solar access, or other amenities. Such zoning ordinances or by-laws shall state the specific improvements or amenities or locations of proposed uses for which the special permits shall be granted, and the maximum increases in density of population or intensity of use which may be authorized by such special permits.

Zoning ordinances or by-laws may provide that special permits may be granted for multi-family residential use in nonresidentially zoned areas where the public good would be served and after a finding by the special permit granting authority, that such nonresidentially zoned area would not be adversely affected by such a residential use, and that permitted uses in such a zone are not noxious to a multi-family use.

Zoning ordinances or by-laws may provide for special permits authorizing the transfer of development rights of land within or between districts. These zoning ordinances or by-laws shall include incentives such as increases in density of population, intensity of use, amount of floor space or percentage of lot coverage, that encourage the transfer of development rights in a manner that protect open space, preserve farmland, promote housing for persons of low and moderate income or further other community interests; provided, however, that nothing herein shall prohibit a zoning ordinance or by-law from allowing transfer of development rights to be permitted as of right without the need for a special permit or other discretionary zoning approval.

Zoning ordinances or by-laws may also provide that cluster developments or planned unit developments shall be permitted upon the issuance of a special permit.

Notwithstanding any provision of this section to the contrary, zoning ordinances or by-laws may provide that cluster developments shall be permitted upon review and approval by a planning board pursuant to the applicable provisions of sections 81K to 81GG, inclusive, of chapter 41 and in accordance with its rules and regulations governing subdivision control.

''Cluster development'' means a residential development in which the buildings and accessory uses are clustered together into one or more groups separated from adjacent property and other groups within the development by intervening open land. A cluster development shall be permitted only on a plot of land of such minimum size as a zoning ordinance or by-law may specify which is divided into building lots with dimensional control, density and use restrictions of such building lots varying from those otherwise permitted by the ordinance or by-law and open land. Such open land when added to the building lots shall be at least equal in area to the land area required by the ordinance or by-law for the total number of units or buildings contemplated in the development. Such open land may be situated to promote and protect maximum solar access within the development. Such open land shall either be conveyed to the city or town and accepted by it for park or open space use, or be conveyed to a non-profit organization the principal purpose of which is the conservation of open space, or to be conveyed to a corporation or trust owned or to be owned by the owners of lots or residential units within the plot. If such a corporation or trust is utilized, ownership thereof shall pass with conveyances of the lots or residential units. In any case where such land is not conveyed to the city or town, a restriction enforceable by the city or town shall be recorded providing that such land shall be kept in an open or natural state and not be built for residential use or developed for accessory uses such as parking or roadway.

''Planned unit development'' means a mixed use development on a plot of land containing a minimum of the lesser of sixty thousand square feet or five times the minimum lot size of the zoning district, but of such larger size as an ordinance or by-law may specify, in which a mixture of residential, open space, commercial, industrial or other uses and a variety of building types are determined to be sufficiently advantageous to render it appropriate to grant special permission to depart from the normal requirements of the district to the extent authorized by the ordinance or by-law. Such open space, if any, may be situated to promote and protect maximum solar access within the development.

Zoning ordinances or by-laws may also provide for the use of structures as shared elderly housing upon the issuance of a special permit. Such zoning ordinances or by-laws shall specify the maximum number of elderly occupants allowed, not to exceed a total number of six, any age requirements and any other conditions deemed necessary for the special permits to be granted.

Zoning ordinances or by-laws may provide that certain classes of special permits shall be issued by one special permit granting authority and others by another special permit granting authority as provided in the ordinance or by-law. Such special permit granting authority shall adopt and from time to time amend rules relative to the issuance of such permits, and shall file a copy of said rules in the office of the city or town clerk. Such rules shall prescribe a size, form, contents, style and number of copies of plans and specifications and the procedure for a submission and approval of such permits.

Zoning ordinances or by-laws may provide for associate members of a planning board when a planning board has been designated as a special permit granting authority. One associate member may be authorized when the planning board consists of five members, and two associate members may be authorized when the planning board consists of more than five members. A city or town which establishes the position of associate member shall determine the procedure for filling such position. If provision for filling the position of associate member has been made, the chairman of the planning board may designate an associate member to sit on the board for the purposes of acting on a special permit application, in the case of absence, inability to act, or conflict of interest, on the part of any member of the planning board or in the event of a vacancy on the board.

Each application for a special permit shall be filed by the petitioner with the city or town clerk and a copy of said application, including the date and time of filing certified by the city or town clerk, shall be filed forthwith by the petitioner with the special permit granting authority. The special permit granting authority shall hold a public hearing, for which notice has been given as provided in section eleven, on any application for a special permit within sixty-five days from the date of filing of such application; provided, however, that a city council having more than five members designated to act upon such application may appoint a committee of such council to hold the public hearing. The decision of the special permit granting authority shall be made within ninety days following the date of such public hearing. The required time limits for a public hearing and said action, may be extended by written agreement between the petitioner and the special permit granting authority. A copy of such agreement shall be filed in the office of the city or town clerk. A special permit issued by a special permit granting authority shall require a two-thirds vote of boards with more than five members, a vote of at least four members of a five member board, and a unanimous vote of a three member board.

Failure by the special permit granting authority to take final action within said ninety days or extended time, if applicable, shall be deemed to be a grant of the special permit. The petitioner who seeks such approval by reason of the failure of the special permit granting authority to act within such time prescribed, shall notify the city or town clerk, in writing within fourteen days from the expiration of said ninety days or extended time, if applicable, of such approval and that notice has been sent by the petitioner to parties in interest. The petitioner shall send such notice to parties in interest by mail and each such notice shall specify that appeals, if any, shall be made pursuant to section seventeen and shall be filed within twenty days after the date the city or town clerk received such written notice from the petitioner that the special permit granting authority failed to act within the time prescribed. After the expiration of twenty days without notice of appeal pursuant to section seventeen, or, if appeal has been taken, after receipt of certified records of the court in which such appeal is adjudicated, indicating that such approval has become final, the city or town clerk shall issue a certificate stating the date of approval, the fact that the special permit granting authority failed to take final action and that the approval resulting from such failure has become final, and such certificate shall be forwarded to the petitioner. The special permit granting authority shall cause to be made a detailed record of its proceedings, indicating the vote of each member upon each question, or if absent or failing to vote, indicating such fact, and setting forth clearly the reason for its decision and of its official actions, copies of all of which shall be filed within fourteen days in the office of the city or town clerk and shall be deemed a public record, and notice of the decision shall be mailed forthwith to the petitioner, applicant or appellant, to the parties in interest designated in section eleven, and to every person present at the hearing who requested that notice be sent to him and stated the address to which such notice was to be sent. Each such notice shall specify that appeals, if any, shall be made pursuant to section seventeen and shall be filed within twenty days after the date of filing of such notice in the office of the city or town clerk.

Zoning ordinances or by-laws shall provide that a special permit granted under this section shall lapse within a specified period of time, not more than 3 years, which shall not include such time required to pursue or await the determination of an appeal referred to in section seventeen, from the grant thereof, if a substantial use thereof has not sooner commenced except for good cause or, in the case of permit for construction, if construction has not begun by such date except for good cause.

Zoning ordinances or by-laws shall also provide that uses, whether or not on the same parcel as activities permitted as a matter of right, accessory to activities permitted as a matter of right, which activities are necessary in connection with scientific research or scientific development or related production, may be permitted upon the issuance of a special permit provided the granting authority finds that the proposed accessory use does not substantially derogate from the public good.

In any city or town that accepts this paragraph, zoning ordinances or by-laws may provide that research and development uses, whether or not the uses are currently permitted as a matter of right, may be permitted as a permitted use in any non-residential zoning district which is not a residential, agricultural or open space district upon the issuance of a special permit provided the special permit granting authority finds that the uses do not substantially derogate from the public good.

''Research and development uses'' shall include any 1 or more of investigation, development, laboratory and similar research uses and any related office and, subject to the following limitations, limited manufacturing uses and uses accessory to any of the foregoing.

''Limited manufacturing'' shall, subject to the issuance of the special permit, be an allowed use, if the following requirements are satisfied: (1) the manufacturing activity is related to research uses; (2) no manufacturing activity customarily occurs within 50 feet of a residential district; and (3) substantially all manufacturing activity customarily occurs inside of buildings with any manufacturing activities customarily occurring outside of buildings subject to conditions imposed in the special permit.

A hazardous waste facility as defined in section two of chapter twenty-one D shall be permitted to be constructed as of right on any locus presently zoned for industrial use pursuant to the ordinances and by-laws of any city or town provided that all permits and licenses required by law have been issued to the developer and a siting agreement has been established pursuant to sections twelve and thirteen of chapter twenty-one D, provided however, that following the submission of a notice of intent, pursuant to section seven of chapter twenty-one D, a city or town may not adopt any zoning change which would exclude the facility from the locus specified in said notice of intent. This section shall not prevent any city or town from adopting a zoning change relative to the proposed locus for the facility following the final disapproval and exhaustion of appeals for permits and licenses required by law and by chapter twenty-one D.

A facility, as defined in section one hundred and fifty A of chapter one hundred and eleven, which has received a site assignment pursuant to said section one hundred and fifty A, shall be permitted to be constructed or expanded on any locus zoned for industrial use unless specifically prohibited by the ordinances and by-laws of the city or town in which such facility is proposed to be constructed or expanded, in effect as of July first, nineteen hundred and eighty-seven; provided, however, that all permits and licenses required by law have been issued to the proposed operator. A city or town shall not adopt an ordinance or by-law prohibiting the siting of such a facility or the expansion of an existing facility on any locus zoned for industrial use, or require a license or permit granted by said city or town, except a special permit imposing reasonable conditions on the construction or operation of the facility, unless such prohibition, license or permit was in effect on or before July first, nineteen hundred and eighty-seven; provided, however, that a city or town may adopt and enforce a zoning or non-zoning ordinance or by-law of general application that has the effect of prohibiting the siting or expansion of a facility in the following areas: recharge areas of surface drinking water supplies as shall be reasonably defined by rules and regulations of the department of environmental protection, areas subject to section forty of chapter one hundred and thirty-one, and the regulations promulgated thereunder; and areas within the zone of contribution of existing or potential public supply wells as defined by said department. No special permit authorized by this section may be denied for any such facility by any city or town; provided, however, that a special permit granting authority may impose reasonable conditions on the construction or operation of the facility, which shall be enforceable pursuant to the provisions of section seven.