WAC 173-183-340
Oil class ranking. (1) The purpose of
this section is to provide a relative ranking of the severity
of effects caused by a spilled oil. The ranking is based on
the known chemical, physical, and mechanical properties of
oils in the six classes identified in this section, as well as
other properties affecting propensity to cause acute toxicity
and mechanical injury, and to persist in the environment. For
purposes of the compensation schedule, relative rankings of
the severity of effects caused by a spilled oil are provided
for the following classes of oils:
(a) Prudhoe Bay crude oil;
(b) Bunker C;
(c) No. 2 fuel oil;
(d) Gasoline;
(e) Kerosene; and
(f) Kerosene-type jet fuel.
(2) The relative ranking scores for the oil classes range
from 1 to 5, where 1 represents the least harmful effect and 5
represents the most harmful effect. For purposes of RCW 90.48.366 and 90.48.367, the acute toxicity, mechanical
injury, and persistence relative ranking scores for the oils
described by the classes enumerated in subsection (1) of this
section shall be as follows:
Table 1. Acute Toxicity, Mechanical Injury and
Persistence Relative Ranking Scores for Classified Oils (OIL).
| Oil Class |
Acute
Toxicity |
Mechanical
Injury |
Persistence |
| Prudhoe Bay Crude Oil |
0.9 |
3.6 |
5 |
| Bunker C |
2.3 |
5.0 |
5 |
| No. 2 Fuel Oil |
2.3 |
3.2 |
2 |
| Gasoline |
5.0 |
1.0 |
1 |
| Kerosene |
1.4 |
2.4 |
1 |
| Kerosene-type Jet Fuel |
1.4 |
2.4 |
1 |
(3) In cases where the spilled oil is not described by
any of the oil classes listed in subsection (1) of this
section, or is a mixture of oils, the department shall
determine the acute toxicity, mechanical injury, and
persistence scores as follows:
(a) By assigning the acute toxicity, mechanical injury,
and persistence scores assigned to the oil class best
describing the spilled oil from subsection (2) of this
section; or
(b) By using the following guidance to determine the
acute toxicity, mechanical injury, and persistence relative
ranking scores:
(i) Acute toxicity relative ranking score. An acute
toxicity raw score is determined by summing the weighted
averages of the 1-, 2-, and 3-ringed aromatic compounds
comprising the spilled oil and dividing this sum by 107, where
aromatic compound composition is determined by percent-weight,
and weighting is determined by aqueous solubility of the
aromatic compounds, as described by the following formula:
Acute Toxicity Raw Score =
[(SOL1*PCT-WT1)+(SOL2*PCT-WT2)+(SOL3*PCT-WT3)]/107
where SOLi = solubility in seawater of i-ring aromatic
hydrocarbons, and
PCT-WTi = percent weight of i-ring aromatic hydrocarbons
in the spilled oil, i = 1, 2, and 3.
The final acute toxicity relative ranking score is
determined by rounding the acute toxicity raw score to the
nearest 0.1 using standard rounding procedures where decimals
less than 0.05 are rounded down and decimals equal to or
greater than 0.05 are rounded up.
(ii) Mechanical injury relative ranking score. A
mechanical injury raw score is determined by subtracting 0.688
from the specific gravity of the spilled oil and dividing this
result by 0.062 as follows:
Mechanical Injury Score = (SP - 0.688)/0.062
where SP = specific gravity of the spilled oil.
The final mechanical injury ranking score is determined
by rounding the mechanical injury raw score to the nearest 0.1
using standard rounding procedures where decimals less than
0.05 are rounded down and decimals equal to or greater than
0.05 are rounded up.
(iii) Persistence relative ranking score. A persistence
relative ranking score is determined from empirical data
describing the length of time the spilled oil is known to, or
is likely to, persist in a variety of habitat types. Scoring
is assigned on a 1 to 5 scale as follows:
| SCORE |
ANTICIPATED PERSISTENCE |
| 5 |
5 - 10 years or more |
| 4 |
2 - 5 years |
| 3 |
1 - 2 years |
| 2 |
1 month to 1 year |
| 1 |
days to weeks. |
(4) In cases where the spilled oil is comprised of two or
more types of oil, damages shall be calculated under the
schedule for each oil type and then summed to calculate total
damages liability.
[Statutory Authority: Chapter 90.48 RCW. 92-10-005 (Order
91-13), § 173-183-340, filed 4/23/92, effective 5/24/92.]
NOTES:
Reviser's note: The brackets and enclosed material in the text of the
above section occurred in the copy filed by the agency.