Md. Code Ann., Pub. Safety § 6-319
(a) An abatement order directed to the occupant of the premises shall be served within 5 days after the order is issued:
(2) if no occupant or adult is found on the premises:
(i) by posting a true copy of the order in a conspicuous place on the door or other prominent entrance to the premises; and
(ii)1. by mailing a copy of the order by certified mail, return receipt requested, to the occupant at the occupant's last known address; or
(b) An abatement order directed to the owner of the premises shall be served within 5 days after the order is issued:
(2) if the owner is absent from the State or the owner's whereabouts are unknown to the State Fire Marshal:
(i) by posting a true copy of the order in a conspicuous place on the door or other prominent entrance to the premises; and
(ii)1. by mailing a copy of the order by certified mail, return receipt requested, to the owner at the owner's last known address; or
Added by Acts 2003, c. 5, § 2, eff. Oct. 1, 2003.