This section provides an overview of the cleanup process that typically occurs at a site following the discovery of a release or threatened release of a hazardous substance to the environment. See WAC 173-340-510 for an overview of the administrative options for investigating and cleaning up a site. If there are any inconsistencies between this section and any specifically referenced sections, the referenced section governs.

(1) Release reporting. Within 90 days of discovering a hazardous substance release or threatened release that may pose a threat to human health or the environment, an owner or operator must report the release to ecology as described in WAC 173-340-300. Other persons are encouraged to report such releases. Some releases are exempt from the release reporting requirements of this chapter, including those previously reported to ecology under the state's hazardous waste, underground storage tank, or water quality laws. The term "hazardous substance" includes a broad range of substances as defined in WAC 173-340-200.

(2) Initial investigation. Within 90 days of learning of a hazardous substance release, ecology conducts an initial investigation under WAC 173-340-310 to confirm whether a release occurred that poses a threat and to determine whether further remedial action is necessary to confirm or address that threat. Ecology may extend an initial investigation when independent remedial actions are completed within 90 days of release discovery. Ecology notifies owners and operators in writing of its determination. For sites where remedial action is necessary, ecology also notifies the public in the Contaminated Site Register and provides information about the site on ecology's website under WAC 173-340-600.

(3) Site hazard assessment and ranking. Based on the results of the initial investigation, ecology assesses and ranks the threats to human health and the environment posed by the site under WAC 173-340-320. Ecology may update the site's hazard assessment and rankings during the cleanup process when new information becomes available or conditions change. Ecology uses the results to support decisions to add or remove sites from the contaminated sites list, prioritize remedial action and funding among and within sites, track cleanup progress, and communicate threats to the public.

(4) Listing. Ecology lists a site based on the results of the initial investigation and the site hazard assessment and ranking.

(a) Contaminated sites list. If further remedial action is necessary, ecology adds the site to the contaminated sites list under WAC 173-340-330. The list also identifies the site's remedial action status. Ecology updates the status during the cleanup process to reflect current conditions. The list is publicly available on ecology's website.

(b) No further action sites list. If no further remedial action is necessary, ecology adds the site to the no further action sites list under WAC 173-340-335. The list identifies whether institutional controls or periodic reviews remain necessary at the site. The list is publicly available on ecology's website.

(5) Interim actions. Under certain conditions it may be necessary or appropriate to conduct an early, interim action at a site before conducting a cleanup action.

(a) WAC 173-340-430 describes when interim actions are typically appropriate at a site and the requirements for such actions.

(b) WAC 173-340-450 describes specific interim actions that UST system owners and operators must perform immediately or shortly after confirming a release from a regulated UST system to reduce the threats posed by the release, prevent any further release, and characterize the nature and extent of the release. As specified in chapter 173-360A WAC, such releases must be cleaned up in accordance with this chapter.

(6) Remedial investigation of site conditions. After a detailed work plan is prepared, a remedial investigation is conducted at the site under WAC 173-340-350 to identify the sources of contamination; to characterize the nature, extent, and magnitude of contamination; and to assess the threats posed by the contamination to human health and the environment. The results of the remedial investigation are used to establish cleanup standards and to develop and evaluate cleanup action alternatives in a feasibility study.

(7) Feasibility study of cleanup action alternatives. Based on the results of the remedial investigation, cleanup action alternatives for addressing the threats posed by the site are developed and evaluated in a feasibility study under WAC 173-340-351. The alternatives are evaluated against the requirements and expectations for cleanup actions in WAC 173-340-360 and 173-340-370. The results of the feasibility study are used to select the cleanup action for a site. A feasibility study is not required to select an applicable model remedy developed by ecology under WAC 173-340-390.

(8) Cleanup action plan. Based on the results of the remedial investigation/feasibility study, a cleanup action is selected and a cleanup action plan is prepared under WAC 173-340-380. The cleanup action plan documents the selected cleanup action and specifies the cleanup standards and other requirements the cleanup action must meet. Cleanup standards are established under Part 7 of this chapter and include the concentrations the cleanup action must meet (cleanup levels), the location where those concentrations must be met (points of compliance), and other regulatory requirements that apply to the cleanup action or site.

(9) Cleanup. After a cleanup action is selected, the cleanup is conducted under WAC 173-340-400 and 173-340-410. Cleanup includes design, construction, operation and maintenance, and monitoring of the cleanup action.

(a) Design. Before starting construction, plans are developed to detail the cleanup action. This includes engineering designs, construction plans and specifications, operation and maintenance plans, and compliance monitoring plans. Before or during this design phase, any permits or approvals needed to construct the cleanup action are identified and resolved.

(b) Construction. Construction of the cleanup action is conducted in accordance with the plans and specifications prepared during the design phase. Upon completion of construction, as-built reports are prepared to document all aspects of construction and compliance with plans and specifications. During and upon completion of construction, ecology may inspect the site and provide construction oversight.

(c) Operation and maintenance. After construction is complete, some cleanup actions need to be operated and maintained for a period of time to achieve cleanup standards. For example, a treatment system may be constructed and used to clean up contaminated groundwater. Operation and maintenance of such cleanup actions is conducted in accordance with a plan developed during the design phase.

(d) Monitoring. During the construction and the operation and maintenance of the cleanup action, the following types of compliance monitoring are conducted. Compliance monitoring is conducted in accordance with a plan developed during the design phase.

(i) Protection monitoring is conducted to confirm that human health and the environment are adequately protected.

(ii) Performance monitoring is conducted to confirm that the cleanup action is achieving or has attained cleanup standards and any other applicable performance standards, such as remediation levels or permit requirements.

(10) Cleanup completion. Ecology determines whether cleanup of the site is complete based on the criteria in WAC 173-340-330(5). Typically, a cleanup is complete if no further remedial action is necessary to achieve cleanup standards at the site. For nonpermanent cleanup actions, such as those involving containment of contamination, post-cleanup controls and monitoring may be necessary as part of the cleanup action to maintain and periodically review compliance with cleanup standards.

(11) Removal from contaminated sites list. After determining the cleanup of the site is complete, ecology removes the site from the contaminated sites list under WAC 173-340-330 and adds the site to the no further action sites list under WAC 173-340-335. The no further action sites list identifies whether institutional controls or periodic reviews remain necessary at the site.

(12) Post-cleanup controls and monitoring. For nonpermanent cleanup actions, after the cleanup is completed and the site is delisted, one or more of the following post-cleanup remedial actions may be needed to control or monitor contamination remaining at the site.

(a) Engineered controls. Engineered controls are containment or treatment systems that prevent or limit movement of, or exposure to, contamination. For example, materials may be placed over contaminated soils to limit contact with contamination. For a cleanup action to remain protective, engineered controls must be operated and maintained in accordance with the plan required under WAC 173-340-400.

(b) Institutional controls. Institutional controls prohibit or limit activities or uses of real property that may interfere with the integrity of engineered controls or result in exposure to contamination remaining at the site. For example, a property may be restricted to industrial land use at sites where cleanup standards are based on such use. Institutional controls may also obligate a person to operate, maintain, or monitor engineered controls to ensure the integrity of the cleanup action. Typically, institutional controls are implemented by recording a restrictive covenant on the property. For a cleanup action to remain protective, institutional controls must be maintained and enforced. See WAC 173-340-440.

(c) Confirmation monitoring. Confirmation monitoring is a type of compliance monitoring used to confirm the long-term effectiveness of a cleanup action after the cleanup is completed. See WAC 173-340-410. For example, confirmation monitoring may be used to confirm that engineered controls are operating properly and effectively limiting the movement of contamination remaining at the site. For a cleanup action to remain protective, confirmation monitoring must be conducted in accordance with the plan required under WAC 173-340-400. Ecology relies on the monitoring data during periodic reviews of post-cleanup site conditions.

(d) Financial assurances. Financial assurances are assurances made to ecology by a person that sufficient financial resources are available to provide for the long-term operation, maintenance, and monitoring of a cleanup action relying on engineered or institutional controls, and for any needed corrective measures. Ecology may require financial assurances under WAC 173-340-440(11).

(e) Periodic reviews. Ecology conducts periodic reviews of post-cleanup site conditions at least once every five years to determine whether they remain protective of human health and the environment. If ecology determines that conditions are not protective and that substantial changes to the cleanup action are necessary, ecology may relist the site on the contaminated sites list and revise the cleanup action plan. See WAC 173-340-420.

(13) Public notice and participation and tribal engagement.

(a) Site-specific information and alerts. For all sites on the contaminated sites list and the no further action sites list, ecology will:

(i) Make key site information publicly available on ecology's website under WAC 173-340-600(5), including the site's listing, remedial action status, hazard rankings, and remedial action plans and reports;

(ii) If requested, notify a person electronically under WAC 173-340-600(6) when the site information specified on ecology's website is added or changed; and

(iii) Provide notice of proposed actions available for public comment in the Contaminated Site Register.

(b) Ecology-conducted and ecology-supervised remedial actions. For ecology-conducted and ecology-supervised remedial actions, ecology provides the public with notice and opportunity to comment and invites tribal engagement on most steps in the cleanup process. For such sites, ecology prepares or requires site-specific public participation and tribal engagement plans. These and other requirements are described in WAC 173-340-600 (8) through (19) and 173-340-620.

(c) Independent remedial actions. For independent remedial actions, ecology provides the public with notice of any reports of such actions received by ecology, the results of any ecology review of such actions, the results of any periodic review of the site, and any institutional controls at the site. These and other requirements are described in WAC 173-340-600(20).