# •**-~** 

# Focus e**i:r·l~ft'I·(/~&~i** 

# Washington Ranking 

# Method
Every hazardous waste site in Washington is unique and poses potentially different 

### type and level of 

### risk to human health and the environment. The Model 

### Toxics Control Act requires lhcsc sitC'S to 

### be ranked relative to each other to guide Ecology's 

### uscof cleanup I"t"5OUI"Ct'S. Working with 

### theScience Advisory 

### Board,**Eco~** has developed a ranking system for hazardous 

### sites 

### known as 

### the Washington Ranking 

## Method.·

. Ecology 

### ranks a site 

### after the agency gathers enough information 

### to complete a site

### hazard assessment. Owners/operators and any otherpotentially liable 

### personsknown to 

### the agency are notified when their 

### hazardoos waste site 

### isranked and placed on Ecology's Hazardous 

### Sites list. Additions to the list are announced twice each 

### year. . 

## What Does the Washington Ranking Method 007 A site's potential threat 

### to human health 

### and the environment 

### is estimated 

### using thedata gathered during the site 

### hazard 

### assessment. The Washington Ranking 

### Methodcategorizes sites on

### the basis of this information. Sites 

### are ranked on a scale of one 

### tofive, 

### with 

### a score ofone 

### representingthe 

### highest level of concern and 

### five the lowest. The Washington 

### Ra.nJdng Method is designed 

### to:

• Provide a consistent, objective means ofassessing 

### sites

• Establish a scientifically defensible method ofevaluating 

### sites

• Maximize accuracy 

### with minimum data

• Provide

### adequate distinction between 

### sites 

## How Will the Rankings Be Used? 11 

### isimporlanJ 

### 10 keep ill mind

### tJuztIttuArdous sittranJ:ing 

### isnot

### theSGme lIS 

### risIc**~ml.** Rather, it is an estimation ofthe potential threat 

### posed by a siterelative to 

## an other ranked sites 

### in thestate. An actual assessment 

### ol site's health 

### risk is detennined after analysis 

### by the state Department of

### Health or by a county healthdepartment.

. The Washington 

### Ranldng Method provides a framework in wNdl to organize 

### and**oom~** 

### sites. However, it isnot 

### the only factor used to determine which sites receive priority for Ecology'S resources. Other considerations include the availability of 

### funds, the potential cost

### ofcleanup, the level ofcooperation. 

### shown by 

### a responsible party, and public concern about a site. --.. The ModeJ Taxies Control Act was implemented in March, 1989, after voter approval oflnJtiative 97. 

### Some of 

### thesites being investigated and cleaned up under the Ad were already receiving attention under previoasJaws.ln the interest of efficiency, work will continue 

### on most of

### these sites even if 

### they rank lower than newly added sites.

. . . 

## How Does the Washington Ranking Method Work? When ranking a site, Ecology considers the 

### primary routes through which humans or theenvironment could be exposed to hazardous substances found on that site. "These routes include air, surface water and ground water. For each 

### "exposure route", the following information is evaluated to determine the relative risk 

### posed by 

### each site. 

### SubstanceOYracteri.stics Site Chuaeterlstics Exposure Potential Toxicity 

### ofsubstance Migration potential Population

. Quantity ofsubstance 

### Soil permeability 

### Sensitiveenvironment Mobility 

### 01 substance AveragerainfaU Surface water uses Containment 

### flood plain**(irriga~** d.rinJc.ing Terrain sJope water, fisheries) Distance 

### to ground water Ground water uses 

# , April, 1991