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- Taxies Information .e ......".. IUrI 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 major portion of this 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 indiVidualsites: ", . . ~.. - . .~.

• 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, must be

established for each site. Oeanup levels determine at what level a particular

hazardous substance does notthreaten human health orthe environment. Points of

compliance designate location on the site where the cleanup levelsmust bemet.

• Selecting Oeanup Actions:11Usstep involves evaluating methods that couldbe

used to clean a site and then deciding which of those methods would best achieve

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 Aze Set

Eliminating all risks at a contaminated site often is not possible, even after cleanup. And

since any level of exposure 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

longer poses an unacceptable threat to human health and the environment.

• For cancer-causing substances, the acceptable risk level is defined as a conservative

estimate of a person'smances of developing cancer during a lifetime of consistent

exposure to a hazardoussubstance. IT more than one contaminant ispresent OIl a

site, the total health risk for all cancer-causing substances must be mnsidered when

setting cleanup levels.

• For non-carcinogenic subaana», the cleanup level for each substance at a site must be

below that which could cause illness in humans. Ifmore than one substance at a site

affects the body in the same way, the effect of all ofthose substances combined must

be considered when setting cleanup levels.

April 1991

Pwblicatiart 91-5
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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 of permanent cleanup methods

wherever practical. The regulation lists preferred technologies in this order. 1) Reuse

or recycling, 2)Destruction or detoxification, 3) Reduction of the amount of waste, 4)

Contairunent of waste on-site, 5) On-site or off-site disposal.

• The Role of Cost: While cost cannot justify establishing cleanup levels that may

compromise human health or the environment, it can playa role in determining

points of compliance 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 site use and how adjacent properties are

used are important considerations when determining appropriate deanup levels.

For most sites, cleanup levels will be set low enough that uses of the property will

not be restricted in the future. Properties in heavy industrial areas may utilize a

higher risk level. Ifsite 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 or federal 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 lower than what can be reliably measured using today'ssampling

and analytical procedures. In those situations, the lowest reliable measurement

would initially be used. The availability of improved analytical methods will be

periodically reviewed.

Protection After Cleanup

• Confirmational Monitoring: Monitoring must be conducted at each site to verify

that cleanup actions worked and remain effective over time. .

• Periodic Review: If hazardous 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 protection of human health and the environment. Eoology will publish a

notice of all periodic reviews in the site register and provide an opportunity for

public review and comment.