Md. Code, Public Safety § 12-1103
§12–1103.
A carbon monoxide alarm may be combined with a smoke alarm if the combined device complies with:
(1) this subtitle;
(2) Title 9 of this article; and
(3) American National Standards Institute (ANSI)/Underwriters Laboratories (UL) standards 217 and 2034 or ANSI/UL 268 and 2075.