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# Cleaning Up Hazardous Waste Sites: lual'.I.' ., 

### ECOL 0 G' 

# Cleanup Standards and Cleanup Actions
Background Washington's hazardous waste**clean~** law, the Model Toxies Control 

### Act, mandates that site cleanups protect the state's dtizens and environment-In developing the Ad's cleanup regulation, Ecology established cleanup standards and requirements for deanup actions that fulfill this mandate. A majorportion ofthis effort 

### was completed in 

### February, 1991.

. . The Department of 

### Ecologyhas worked with the state Science 

### Advisory Board and representatives from

### business, local government and environmenlal gIoops to define site cleanup levels. 

## Determining Cleanup Requirements The Model ToxiesControl Ad deanup

### ~tio~**d~** a

### ~c>-sIeP.a~ 

# tr4-:'. establishing cleanup 

### requirements for 

### indiVidual sites: ", . .**~..** - .**.~.**
• Establishing Oeanup Standards: The standards provide a uniform. statewide approach to cleanup that can be applied on a site-by-site 

### basis. The two prinwy components of the 

### standards, cleanup levels and points of compliance, mustbe established for each site. Oeanup levels determine atwhat level a particular hazardous substance does 

### notthreatenhuman healthorthe environment. Points of compliance designate location on the site where

### the cleanup levels

# mustbemet.

• Selecting OeanupActions: 11Usstep involves evaluating methods that could

### be used to clean a siteand then deciding which ofthose methods would bestachieve cleanup standards. Aside from meeting the standards, the deanup actions must also provide permanent cleanup solutions, a reasonable time frame for cleanup and include monitoring to 

### ensure effectiveness. 

### STEP 1 - How Cleanup Levels AzeSet Eliminating all risks at a contaminated site often is not possible, even after cleanup. And since any level ofexposure to a hazardous substance is assumed to result in some risk, "clean" generally means that a site is cleaned up to the point that contamination no longerposes an unacceptable threat to human health and the environment. • For 

### cancer-causingsubstances, the acceptable risk level is defined as a conservative estimate of aperson's

# mances ofdeveloping cancerduring a lifetime of consistent exposure to a hazardous substance. ITmore than one contaminant ispresent OIl a site, the totalhealth risk for all cancer-causing substances must be mnsidered when setting cleanup levels. • For 

### non-carcinogenicsubaana», the cleanup level for each substanceat a site must be below that which could cause illness in humans. Ifmore than one substance at a site affects thebody in the same way, the effect ofall ofthose substancescombined must be considered when setting cleanuplevels.



### April 1991 Pwblicatiart 91-5

# • STEP 2 - 

### Selecting Cleanup Actions Step two of the cleanup process involves choosing the method or methods used to clean upa site.

• Permanent Cleanups; Ecology will require use ofpermanent cleanup methods whereverpractical. The regulation lists preferred technologies in this order. 1) 

### Reuse or recycling, 2)Destruction or detoxification, 3) Reduction of the amount ofwaste, 4) Contairunent ofwaste on-site, 5) On-site or off-site disposal.

• The Role ofCost: While cost cannotjustify establishing cleanup levels that may compromise human health or the environment, it can playa role in determining points ofcompliance and cleanup actions. Permitting less stringent cleanup levels based on cost would be inconsistent with the intent of the Model Tosdcs Control Act.

• Public Review: Ecology describes the method of site cleanup in a 

### draft -cleanup action plan", which is circulated for public review and comment. This plan is then finalized and used as the basis (or any negotiations with potentially liable persons who will be doing the site cleanup.

.. 

### Other Factors Affecting 

### Cleanup Requirements

• Property Use: Factors such as zoning, past siteuse and how adjacent properties are 

### used are important considerations when determining appropriate deanup levels. For most sites, cleanup levels will be set low enough thatuses ofthe 

### property will not be restricted in the future. Properties in heavy industrial areas may utilize a higher risk level. If site use changes after cleanup, the standards will be reviewed to ensure that cleanup levels protect human health and the environment.

• Applicable State and Federal Laws: Oeanup levels and methods used must comply with existing state orfederal laws.

• Environmental Conditions: Washington's diverse environment presents many variables in soil conditions, water tables, climate, and plant and animal communities. These variables 

### need to be considered because 

### they effect the way hazardous substances interact on a site and how they impact humans and wildlife.

• Technology: Although cleanup technologies are developing rapidly, many contaminants are still difficult or impossible to remove from soil and water. For this reason, some flexibility is provided to consider technologica1limitations when setting cleanup levels. Additionally, in some cases, cleanup levels are set at concentrations lowerthan what can be reliably measured using today's sampling and analyticalprocedures. In those situations, the lowest reliable measurement would initially be used. The availability ofimproved analytical methods will be periodicallyreviewed. 

### Protection After Cleanup

• ConfirmationalMonitoring: Monitoring must be conducted at each site 

### to verify that cleanup actions worked and remain effective over time.

.

• Periodic Review: Ifhazardous materials remain at a site at levels which exceed Method A or Bcleanup levels, Ecology will review the site

### every five years to ensure continued protectionofhuman health and the environment. Eoology will publish a notice ofall periodic reviews in the site registerand provide an opportunity for public review and comment.