(1) The RDA committee chair shall, in consultation with the OSC and RDA committee, determine the following:

(a) For spills into marine or estuarine environments excluding the Columbia River estuary:

(i) The acute toxicity, mechanical injury and persistence oil class rankings for the spilled oil as provided in WAC 173-183-340;

(ii) Subregion(s) exposed to the spilled oil;

(iii) Habitat types exposed to the spilled oil as classified in WAC 173-183-410 for spills of 1,000 gallons or more;

(iv) Percent coverage of each habitat type within the area of spill exposure for spills of 1,000 gallons or more;

(v) Percent coverage of habitat types present within the subregion(s) exposed to spilled oil for spills of less than 1,000 gallons.

(vi) A spill's habitat vulnerability scores (HVS) for acute toxicity, mechanical injury, and persistence as determined by the procedures outlined in WAC 173-183-400; and

(vii) The spill vulnerability scores (SVSAT, SVSMI, SVSPER) for the most vulnerable season affected by the spill using the formula provided in WAC 173-183-400.

(b) For spills in the estuarine waters of the Columbia River:

(i) The acute toxicity, mechanical injury, and persistence oil class rankings for the spilled oil as provided in WAC 173-183-340;

(ii) The cell(s) exposed to the spilled oil; and

(iii) The spill vulnerability score (SVS) for the most vulnerable season affected by the spilled oil using the procedures provided in WAC 173-183-500.

(c) For spills in freshwater streams, rivers, and lakes:

(i) The acute toxicity, mechanical injury and persistence oil class rankings for the spilled oil as provided in WAC 173-183-340;

(ii) Freshwater vulnerability score as described in WAC 173-183-610;

(iii) Freshwater habitat index as described in WAC 173-183-620; and

(iv) Spill vulnerability score (SVS) as outlined in WAC 173-183-600 for each stream, river, and/or lake environment exposed to the spill; and

(d) For spills in freshwater wetlands:

(i) The acute toxicity, mechanical injury, and persistence oil class rankings for the spilled oil as provided in WAC 173-183-340;

(ii) Freshwater wetland vulnerability score as described in WAC 173-183-710;

(iii) Spill vulnerability score (SVS) as outlined in WAC 173-183-700 for each wetland exposed to the spill.

(2) For spills that enter more than one environment, the RDA committee chair shall, in consultation with the OSC and RDA committee, make the determinations enumerated under subsection (1)(a) through (d) of this section.