Owners and operators must permanently close an UST system, or a tank or piping run that is part of an UST system, in accordance with the requirements of this section.

(1) Notice of intent. Owners and operators must notify the department of their intent to permanently close an UST system, or a tank or piping run that is part of an UST system, at least thirty days, but no more than ninety days, before the planned start date using the applicable form provided by the department. Owners and operators must also confirm the planned start date with the department at least three business days before starting permanent closure.

(2) Decommission. When an UST system, or a tank or piping run that is part of an UST system, undergoes permanent closure, it must be decommissioned in accordance with the requirements of this subsection.

(a) Actions. To decommission an UST system, or a tank or piping run, undergoing permanent closure, the following actions must be completed, as applicable:

(i) Tanks must be emptied and cleaned by removing all liquids and accumulated sludge;

(ii) Piping must be emptied by removing all liquids;

(iii) Tanks must be removed from the ground or closed in place by filling with an inert solid material or in another manner approved by the department;

(iv) Piping must be removed from the ground or closed in place by capping; and

(v) Any liquids or sludge removed from the tanks or piping must be designated and disposed of in accordance with all applicable federal, state, and local requirements.

(b) Performance. Decommissioning must be performed:

(i) By or under the direct supervision of a service provider certified in accordance with Part 9 of this chapter; and

(ii) In accordance with a code of practice. The following codes of practice may be used to meet this requirement:

(A) American Petroleum Institute, Recommended Practice 1604, "Closure of Underground Petroleum Storage Tanks";

(B) American Petroleum Institute, Standard 2015, "Safe Entry and Cleaning of Petroleum Storage Tanks, Planning and Managing Tank Entry from Decommissioning through Recommissioning";

(C) American Petroleum Institute, Recommended Practice 2016, "Guidelines and Procedures for Entering and Cleaning Petroleum Storage Tanks";

(D) American Petroleum Institute, Recommended Practice 1631, "Interior Lining and Periodic Inspection of Underground Storage Tanks";

(E) National Fire Protection Association, Standard 326, "Standard for the Safeguarding of Tanks and Containers for Entry, Cleaning, or Repair"; and

(F) National Institute for Occupational Safety and Health, Publication 80-106, "Criteria for a Recommended Standard: Working in Confined Spaces."

(c) Reporting. Decommissioning must be reported to the department within thirty days using the applicable checklist provided by the department. The checklist must be completed by the service provider.

(3) Site assessment. When an UST system, or a tank or piping run that is part of an UST system, undergoes permanent closure, a site assessment must be conducted around the system or the part of the system being closed in accordance with WAC 173-360A-0730. Unless otherwise directed by the department, a site assessment is not required if:

(a) A release from the UST system had previously been confirmed and reported to the department; and

(b) Further remedial action is necessary to investigate or clean up the confirmed release under WAC 173-360A-0750(4).

(4) Return of facility compliance tag. If there are no UST systems in operation at the UST facility, the facility compliance tag must be returned to the department with the checklist required under subsection (2)(c) of this section.

(5) Partially exempt UST systems – Notice of permanent closure. Owners and operators of a partially exempt UST system identified in WAC 173-360A-0110 (2)(a) must notify the department in writing within thirty days of the permanent closure of the UST system.