(1) Purpose. The site hazard assessment and ranking process provides a method for ecology to assess and rank threats to human health and the environment posed by a site based on information readily available at the time of assessment. The site hazard assessment and ranking process satisfies the requirements of RCW 70A.305.030 (2)(b), and is not a substitute for a remedial investigation. Ecology uses site hazard assessments and rankings to:

(a) Support decisions to add or remove sites from the contaminated sites list under WAC 173-340-330 or the no further action sites list under WAC 173-340-335;

(b) Prioritize remedial actions and allocate agency resources among and within sites as part of program planning and assessment under WAC 173-340-340;

(c) Inform the public and the legislature about the threats posed by contaminated sites;

(d) Reflect changes in threats posed by a site based on new information or changes in site conditions; and

(e) Identify whether the population threatened includes a likely vulnerable population or overburdened community.

(2) Development. Ecology will establish and maintain a site hazard assessment and ranking process.

(a) Functional requirements. The site hazard assessment and ranking process must enable ecology to use readily available information to:

(i) Rank the potential exposure of human and environmental receptors to confirmed or suspected releases of hazardous substances through each environmental medium;

(ii) Rank the severity of such exposures to human health and the environment;

(iii) Identify whether the potentially exposed population includes a likely vulnerable population or overburdened community;

(iv) Identify the environmental health disparity ranking of the potentially exposed population using the environmental health disparities map developed pursuant to RCW 43.70.815 or other readily available information; and

(v) Report the assessor's level of confidence in the information used for the assessment.

(b) Performance standards. Ecology will establish performance standards for assessing the technical validity, efficiency, consistency, and practical utility of the site hazard assessment and ranking process.

(c) Quality assurance. Ecology will periodically assess whether the site hazard assessment and ranking process meets the performance standards established under (b) of this subsection, and update the process as appropriate.

(d) Public participation. When establishing the site hazard assessment and ranking process or making any change to the process that could affect hazard rankings, ecology will provide the public with notice and an opportunity to comment. The public comment period must be at least 30 days.

(3) Implementation.

(a) Applicability and timing.

(i) Ecology will perform a site hazard assessment and ranking before adding or removing a site from the contaminated sites list under WAC 173-340-330 or the no further action sites list under WAC 173-340-335.

(ii) For sites on the contaminated sites list on the effective date of this section, ecology will conduct a site hazard assessment and ranking as resources permit. As part of the strategic plan required under WAC 173-340-340, ecology will develop goals and strategies for completing a site hazard assessment and ranking of such sites.

(iii) Ecology may also conduct a site hazard assessment and ranking when new information becomes available or when site conditions change.

(b) Performance. Ecology will review readily available information when conducting a site hazard assessment and ranking.

(c) Reliance on others. Ecology may rely on another government agency or a contractor to ecology to perform a site hazard assessment and ranking on its behalf, provided:

(i) The agency or contractor is not suspected of having contributed to the release or threatened release; and

(ii) The agency or contractor has no conflict of interest.

(d) Notification. Upon completing a site hazard assessment and ranking, ecology will:

(i) Make the site's current hazard rankings publicly available on ecology's website under WAC 173-340-600(5). The hazard rankings will include the results specified in subsection (2)(a) of this section; and

(ii) If requested, notify a person electronically under WAC 173-340-600(6).