A. At least thirty days before beginning either permanent closure or a change-in-service under subsections B and C of this section, or within another reasonable time period determined by the fire department, owners and operators must notify the fire department of their intent to permanently close or to make the change-in-service, unless such action is in response to corrective action. The required assessment of the excavation zone must be performed after notifying the fire department but before completion of the permanent closure or a change-in-service.

B. To permanently close a tank, owners and operators must empty and clean it by removing all liquids and accumulated sludges. All tanks taken out of service permanently must also be removed from the ground or, upon special approval from the fire department, filled with an inert solid material.

C. Continued use of an underground storage tank system to store a non-regulated substance is considered a change-in-service. Before a change-in-service, owners and operators must empty and clean the tank by removing all liquid and accumulated sludge and conduct a site assessment.

D. Before permanent closure or a change-in-service is completed, owners and operators must measure for the presence of a release where contamination is most likely to be present at the underground storage tank site. In selecting sample types, sample locations, and measurement methods, owners and operators must consider the method of closure, the nature of the stored substance, the type of backfill, the depth to ground water, and other factors appropriate for identifying the presence of a release.

E. If contaminated soils, contaminated ground water, or free product as a liquid or vapor is discovered under subsection A of this section, or by any other manner, owners and operators must begin corrective action.

F. Owners and operators must maintain records demonstrating compliance with closure requirements under this regulation. The results of the excavation zone assessment must be maintained for at least three years after completion of permanent closure of change-in-service in one of the following ways:

G. Where appropriate, a permit issued under Section 17.21.040 satisfies the requirements of this section.