(a) An environmental covenant is perpetual unless it is

(1) by its terms, limited to a specific duration or terminated by the occurrence of a specific event;

(2) terminated by consent under AS 46.04.330;

(3) terminated under (b), (e), or (g) of this section;

(4) terminated by foreclosure of an interest that has priority over the environmental covenant; or

(5) terminated or modified in an eminent domain proceeding, but only if

(A) the department is a party to the proceeding;

(B) every person whose consent is required under AS 46.04.330(a) is given notice of the pendency of the proceeding; and

(C) the court determines, after hearing, that the activity and use limitations subject to termination or modification are no longer required to protect human health, safety, or welfare, or the environment.

(b) The department may terminate or reduce the burden on the real property of an environmental covenant if the department finds that some or all of the activity and use limitations under the environmental covenant are no longer required to protect human health, safety, or welfare, or the environment, or modify the environmental covenant if the department determines that modification is required adequately to protect human health, safety, or welfare, or the environment.

(c) The department shall provide notice of any proposed action under (b) of this section to each person with a current recorded interest in the real property subject to the environmental covenant, each holder, all other persons who originally signed the environmental covenant, or their successors or assigns, and any other person with rights or obligations under the environmental covenant. The department shall provide 60 days for comment on the proposed action by parties entitled to notice. A determination by the department under this subsection is a final agency decision. Any person entitled to notice under this subsection may request an adjudicatory hearing under the procedures established by the department under AS 46.04.890.

(d) A person entitled to notice under (c) of this section may apply in writing to the department for a determination under (b) of this section that an existing environmental covenant be terminated, that the burden of an environmental covenant be reduced, or that an environmental covenant be modified. The application must specify the determination sought by the applicant, the reasons why the department should make the determination, and the information that would support it. If the department fails to begin a proceeding under (b) of this section within 90 days after receiving the application, the applicant may bring a civil action in superior court for termination, reduction of burden, or modification of the environmental covenant under (e) of this section.

(e) The superior court for a recording district in which the real property subject to an environmental covenant is located may, in a de novo action, under the doctrine of changed circumstances, terminate an environmental covenant, reduce an environmental covenant's burden on the real property, or modify the terms of an environmental covenant if the department fails to begin a proceeding within 90 days as provided under (d) of this section. The applicant under (d) of this section, a holder of the environmental covenant, or another person identified in (c) of this section may begin an action under this subsection. The person beginning the action shall serve notice of the action on the department and any person entitled to notice under (c) of this section. The person bringing the action shall make the department a party to the action. The court shall terminate, reduce the burden of, or modify an environmental covenant if the court determines that the person bringing the action shows that some or all of the activity and use limitations under the environmental covenant do not, or are no longer required to, protect human health, safety, or welfare, or the environment.

(f) An environmental covenant may not be extinguished, limited, or impaired through issuance of a tax deed, foreclosure of a tax lien, or application of the doctrine of adverse possession, prescription, abandonment, waiver, lack of enforcement, acquiescence, or a similar doctrine.

(g) The department shall terminate an environmental covenant if the environmental covenant was required under AS 46.04.300 solely because of the level or concentration of residual contamination on the property, and the department determines that level or concentration of residual contamination does not endanger human health, safety, or welfare, or the environment. The department shall provide notice of a termination under this subsection to each person with a current recorded interest in the real property subject to the environmental covenant, each holder, all other persons who originally signed the environmental covenant, or their successors or assigns, and any other person with rights or obligations under the environmental covenant.