Mass. Gen. Laws ch. 40 § 4F
In any city or town which accepts the provisions of this section, any contracts or orders for items of clothing or apparel shall be given to such establishments only as submit to the city or town the name and address of the manufacturer of such items, and the names and addresses of any and all contractors for such items, and only to such establishments as pay the prevailing rate of wages, determined by the commissioner of labor and industries. Said prevailing rates shall be based on wage rates and working hours that have been established by collective bargaining agreement or understanding between organized labor and employers in the apparel industry. Said commissioner shall, upon application from a city or town, prepare and furnish for the use of such city or town a list of the several classifications of labor usually performed by the employees in the apparel trades, together with the prevailing rate of wages and working hours.
A written declaration by the bidder on said contracts or orders for items of clothing or apparel, upon submission of his bid, that each garment to be purchased shall have a union label affixed to such garment shall be sufficient evidence that said manufacturer or contractor pays the prevailing rate of wages based on wage rates and working hours established by collective bargaining or understanding between organized labor and the employer. Every contractor, subcontractor or other employer, engaged in any work to which this section applies, shall keep a true and accurate record of employees, showing the name, address and occupational classification of each employee, and the hours worked by, and the wages paid to, each such employee, and shall furnish to the city or town upon request a true statement of the contents of such record.
Mass. Gen. Laws ch. 40, § 4F