1. (a) The requirements of 18 AAC 75.325 - 18 AAC 75.390 are referred to in this chapter as the "site cleanup rules." The site cleanup rules establish administrative processes and standards to determine the necessity for and degree of cleanup required to protect human health, safety, and welfare, and the environment at a site where a hazardous substance is located.

2. (b) The site cleanup rules apply to

   1. (1) a sudden or recent discharge or release of a hazardous substance, if the department determines under 18 AAC 75.310 that application of the site cleanup rules is necessary; or
   2. (2) a release of a hazardous substance caused by past activities.

3. (c) The site cleanup rules do not apply to

   1. (1) a release from an underground storage tank (UST) subject to AS 46.03.365 - AS 46.03.450 and 18 AAC 78, except as made applicable expressly by 18 AAC 78; or
   2. (2) an oil and gas reserve pit closure and permitted solid waste storage or disposal facility regulated under 18 AAC 60, 18 AAC 62, or 42 U.S.C. 6901 - 6992k (Solid Waste Disposal Act, as amended by the Resource Conservation Recovery Act).

4. (d) A responsible person shall investigate, contain, and perform a cleanup of a discharge or release of a hazardous substance unless

   1. (1) the department makes a written determination that a discharge or release does not pose a threat to human health, safety, or welfare, or to the environment and requires no cleanup action according to the information available at the time of the determination; or
   2. (2) the department issues an order under AS 46.04.020(c), or the commissioner issues an order under AS 46.09.020(c) that the responsible person cease cleanup activities.
5. (e) A person who is not a responsible person and who undertakes a cleanup activity at a site that is subject to the site cleanup rules shall comply with those provisions of the site cleanup rules that are applicable to the particular cleanup activity undertaken.

6. (f) A responsible person shall

   1. (1) to the maximum extent practicable,

      1. (A) use permanent remedies;

      2. (B) recover free product in a manner that

         1. (i) minimizes the spread of contamination into an uncontaminated area by using containment, recovery, and disposal techniques appropriate to site conditions;
         2. (ii) avoids additional discharge; and
         3. (iii) disposes of the recovered free product in compliance with applicable local, state, and federal requirements;
      3. (C) complete cleanup in a period of time that the department determines to be protective of human health, safety, and welfare, and of the environment;
      4. (D) prevent, eliminate, or minimize potential adverse impacts to human health, safety, and welfare, and to the environment, onsite and offsite, from any hazardous substance remaining at the site; and
      5. (E) evaluate and perform a cleanup of surface soil staining attributable to a hazardous substance;
   2. (2) meet the applicable cleanup levels determined under 18 AAC 75.340 - 18 AAC 75.350; and

   3. (3) provide for long-term care and management of a site as required under the site cleanup rules, including proper operation and maintenance of

      1. (A) cleanup techniques and equipment;
      2. (B) monitoring wells and equipment, if required; and
      3. (C) institutional controls, if required under 18 AAC 75.375.
7. (g) If using method two or method three for determining the applicable soil cleanup levels as described in 18 AAC 75.340 and 18 AAC 75.341, or if applying the groundwater cleanup levels at Table C in 18 AAC 75.345, a responsible person shall ensure that, after completing site cleanup, the risk from hazardous substances does not exceed a cumulative carcinogenic risk standard of 1 in 100,000 across all exposure pathways and does not exceed a cumulative noncarcinogenic risk standard at a hazard index of one, reported to one significant figure, across all exposure pathways. Instructions for determining cumulative risk are provided in the department's Procedures for Calculating Cumulative Risk, dated February 1, 2018, and adopted by reference.
8. (h) If proposing an alternative cleanup level for soil or groundwater, based on a site-specific risk assessment under method four in 18 AAC 75.340(f) or under the provisions of 18 AAC 75.345(b)(2), a responsible person shall ensure that the risk from hazardous substances does not exceed the cumulative carcinogenic risk standard of 1 in 100,000 across all exposure pathways and does not exceed the cumulative noncarcinogenic risk standard at a hazard index of one, reported to one significant figure, across all exposure pathways. Instructions for determining cumulative risk are provided in the department's Procedures for Calculating Cumulative Risk, adopted by reference in (g) of this section.

9. (i) A responsible person, owner, or operator shall obtain approval before disposing of soil or groundwater from a site

   1. (1) that is subject to the site cleanup rules; or
   2. (2) for which a written determination from the department has been made under 18 AAC 75.380(d)(1) that allows contamination to remain at the site above method two soil cleanup levels under 18 AAC 75.340(a)(2) or groundwater cleanup levels listed in Table C in 18 AAC 75.345(b).
10. (j) The department will seek public participation regarding activities conducted under the site cleanup rules, using methods that the department determines to be appropriate for seeking public participation.
11. (k) If a discharge, release, or planned cleanup affects an anadromous fish-bearing stream or lake or an area designated under AS 16.20, activities under the site cleanup rules are subject to coordination with appropriate resource agencies, including the Department of Fish and Game under AS 16.05.871(a) or AS 16.20.

(Eff. 1/22/99, Register 149; am 8/27/2000, Register 155; am 1/30/2003, Register 165; am 10/9/2008, Register 188; am 6/17/2015, Register 214; am 1/1/2016, Register 217; am 11/6/2016, Register 220; am 9/29/2018, Register 227)

Authority: AS 46.03.020, AS 46.03.740, AS 46.04.070, AS 46.03.050, AS 46.03.822, AS 46.09.020, AS 46.03.710, AS 46.04.020