Maryland Code, Environment § 14-115

(a) The Department may summon witnesses, administer oaths, and require the production of records, books, and documents for examination at any hearing or investigation it conducts.

(b) If any person fails or refuses to comply with a subpoena issued by the Department, or if any witness refuses to testify as to any matter regarding which the witness may be interrogated, any court of competent jurisdiction, upon the application of the Department, may issue an attachment for the person and compel the person to comply with the subpoena, and appear before the Department and produce records, books, and documents for examination and give testimony. If a person disobeys a subpoena or refuses to testify, the court may punish the person for contempt.