Mass. Gen. Laws ch. 149, § 24B: Contract provisions preventing employment of certain persons on account of age

Section 24B. Any provision in any contract, agreement or understanding entered into on or after September first, nineteen hundred and eighty-four, which shall prevent the private sector employment of any person over the age of forty because of his age, except as permitted by subsection 17 of section 4 of chapter one hundred and fifty-one B, shall be null and void.