Maryland Code, Tax-General § 2-114

(a) Notwithstanding the provisions of § 9-602 of the Criminal Law Article and subject to subsections (b), (c), (d), and (e) of this section, the Comptroller may monitor and record incoming telephone calls to employees of the Comptroller's call centers to telephones within the offices of the Comptroller for training, quality control, and employee safety purposes.

(b) Any monitored or recorded telephone call shall contain a notice to the telephone caller that “Your call may be recorded or monitored for training and quality control purposes”.

(d) Notwithstanding any other provision of law, information derived from an incoming telephone call to employees of the Comptroller's call centers may not be used in any criminal or civil proceeding against any Maryland taxpayer unless the caller has made a personal and imminent threat against an employee or property of the State.

(e) Recorded telephone calls may not be retained by the Office of the Comptroller for longer than 60 days, except: