Md. Code, Public Safety § 12–917

(a) A person may not:

(1) willfully and persistently operate in the State a boiler or pressure vessel, except a pressure vessel covered by an owner-user inspection service as provided by this subtitle, without a certificate;

(2) operate in the State a boiler or pressure vessel at a pressure exceeding that specified on the certificate; or

(3) interfere with or impede the official duties of the Commissioner, an authorized representative of the Commissioner, or a member of the Board.

(b) A person who violates this section is guilty of a misdemeanor and on conviction is subject for each violation to imprisonment not exceeding 5 years or a fine not exceeding $5,000 or both.