Mass. Gen. Laws ch. 149 § 11
The department may require every physician treating a patient whom he believes to be suffering from any ailment or disease contracted as a result of the nature, circumstances or conditions of the patient's employment to report such information relating thereto as it may require, within such time as it may fix, and it may issue a list of such diseases which shall be regularly reported upon by physicians, and may add to or change such list at any time. The department shall pay no fee for such report. Copies of all such reports and all statistics and data compiled therefrom shall be kept by it, and shall be furnished on request to the department of industrial accidents and the department of public health. No such report shall be subject to summons nor shall its contents be made public.
Mass. Gen. Laws ch. 149, § 11