Any person, including a person that owns an interest in the real property, the Agency, or a municipality or other unit of local government, may be a holder of an environmental covenant. An environmental covenant may identify more than one holder. The interest of a holder of an environmental covenant is an interest in real property. A right of an agency under this subtitle or under an environmental covenant, other than a right as a holder, is not an interest in real property. An agency is bound by any obligation it assumes in an environmental covenant, but an agency does not assume obligations merely by signing an environmental covenant. Any person other than an agency that signs an environmental covenant is bound by the obligations the person assumes in the covenant, but signing the covenant does not change obligations, rights, or protections granted or imposed under law other than this subtitle except as provided in the covenant. The provisions of this subsection apply to interests in real property in existence at the time an environmental covenant is created or amended. An interest that has priority under other law is not affected by an environmental covenant unless the person that owns the interest subordinates that interest to the covenant. A person that owns an interest that has priority under other law is not required under this subtitle to subordinate that interest to an environmental covenant or to agree to be bound by the covenant. A subordination agreement may be contained in an environmental covenant covering real property or in a separate record. If the environmental covenant covers commonly owned property in a common interest community, the record may be signed by any person authorized by the governing board of the owners’ association. An agreement by a person to subordinate an interest that has priority under other law to an environmental covenant affects the priority of that person’s interest but does not by itself impose any affirmative obligation on the person with respect to the environmental covenant.