12- 180 C.M.R. ch. 11, § 15
Whenever the executive director prepares a notice under this Chapter, the executive director shall administratively determine whether the employer shall post the notices or forward them to all affected employees by postpaid first class mail, electronic mail or by other acceptable means. The executive director shall specify the places and periods of posting, and the manner of determining the date of its commencement. The posting period may not be less than 7 calendar days, except for extraordinary circumstances. The employer shall take reasonable precautions to ensure that posted notices are not altered, covered, defaced or removed before the completion of the posting period and shall notify the executive director of satisfaction of the posting requirements.
12- 180 C.M.R. ch. 11, § 15