Section 36. The department shall keep records of the admission, treatment and periodic review of all persons admitted to facilities under its supervision. Such records shall be private and not open to public inspection except (1) upon proper judicial order whether or not in connection with pending judicial proceedings, (2) that the commissioner shall allow the attorney of a patient or resident to inspect records of said patient or resident if requested to do so by the patient, resident or attorney, (3) that the commissioner may permit inspection or disclosure when in the best interest of the patient or resident as provided in the rules and regulations of the department and (4) as required by section one hundred and seventy-eight C to one hundred and seventy-eight O, inclusive, of chapter six. This section shall govern the patient records of the department notwithstanding any other provision of law. Each facility, subject to this chapter and section 19 of chapter 19, that provides mental health care and treatment shall maintain patient records, as defined in the first paragraph of section 70 of chapter 111, for at least 20 years after the closing of the record due to discharge, death or last date of service. A facility shall not destroy such records until after the retention period has elapsed and only upon notifying the department of public health that the records will be destroyed, provided that the department shall promulgate regulations further defining an appropriate notification process. On the notice of privacy practices distributed to its patients, each facility shall provide: (i) information concerning the provisions of this section; and (ii) the hospital or clinic's records termination policy.