Step five: Check Washington state-only criteria

In Washington, businesses must check if their waste meets state-only dangerous waste criteria. This criteria is applied to wastes in addition to the federal toxic characteristic "F, P, U, or K" listed waste codes.

State-only criteria for:

Toxic wastes (coded WT01 or WT02) are determined based on the concentration of toxic components.
Persistent wastes (coded WP01, WP02, WPCB, or WP03) include polycyclic aromatic hydrocarbons (PAHs) halogenated organic compounds (HOCs), and some polychlorinated biphenyls (PCBs).
Solid corrosive wastes (coded WSC2) are solid or semi-solid wastes that have a pH that falls within the corrosive ranges listed below.

Is it a special waste?
Special wastes are a type of state-only dangerous waste that pose a relatively low hazard to human health and the environment. Generators can manage special wastes a couple different ways.

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State-only toxic wastes

The concentration of a waste's toxic components determines if it meets state-only toxic criteria and how it should be coded:

WT01 wastes have a 2.2 quantity exclusion limit (QEL), which also determines your generator category.
WT02 wastes, refer to the dangerous waste criteria in the regulations (WAC 173-303-100).

Testing wastes for toxicity

You can test if a waste meets state-only toxic criteria by using the following methods.

Chemical testing at an analytical lab can give you data about your waste if you are uncertain of its composition.

If you receive more than one test endpoint (that is, fish, oral-rat, inhalation-rat, or dermal-rabbit), the value with the highest toxicity must be used.

For example:

Results from tests on salmonids (the family of fish that includes salmon, trout, and other fish) must be used before tests on minnows.
Results from minnows must be used before tests on other animals.

These show the results from previous tests for specific chemicals. To use this method you will need to know the concentration of specific chemicals in your waste. Use the most conservative results noted in the material’s safety data sheet (SDS) and databases.

Here are some common toxicity databases:

How to verify test results against state-only toxic criteria

Once you know the test results for your waste:

Use the equation listed under dangerous waste criteria (WAC 173-303-100(5)(b)(ii)).
Based on that equation, determine if your waste meets the criteria noted in the Toxic Category Table (WAC 173-303-100(5)(b)(i)).

State-only persistent wastes

Persistent wastes have chemicals that are slow to break down, linger in the environment, and can accumulate in living tissue. Here are the types of persistent wastes to look out for.

Halogenated organic compounds (HOCs)

Coded: WP01 or WP02

HOCs are measured in parts per million (ppm) and are coded based on concentrations:

WP01: If the concentration of HOC waste is greater than 1% (10,000 ppm). This is considered an extremely hazardous waste (EHW).
WP02: If the concentration of HOC waste is greater than 100 ppm (0.01-1%). This is considered dangerous waste (DW) only.

What are HOCs?

HOCs are any organic (carbon-based) compound with at least one atom of:

Bromine, or
Chlorine, or
Fluorine, or
Iodine bonded directly to a carbon atom.

How do you know if you have HOCs?

Check your Safety Data Sheet (SDS or MSDS) and look for the above four chemicals or their prefixes.
For example: Chlorine.
Another option is to test the chemical.

Polychlorinated biphenyls (PCBs)

Coded: WPCB

Polychlorinated biphenyls (PCBs) are very persistent — they last for decades in people, other animals, and the environment. In Washington, the WPCB code (WAC 173-303-9904) applies to the following with concentrations of 2 parts per million (ppm) or greater:

Undrained transformers.
Capacitors.
Bushings containing PCB fluids.

It also includes certain wastes from:

Salvaging.
Rebuilding.
Discarding.

See the WPCB code (WAC 173-303-9904) or our PCB Dangerous Waste Guide for more information.

Can PCB wastes be excluded?

Some of these wastes may be excluded. See our PCB Dangerous Waste Guide for more information.

State-only solid corrosives

Coded: WSC2

A solid or semi-solid waste can designate as corrosive if its pH is within the corrosive range. To test pH, use a solution of 50% deionized water and 50% of your waste material (you need water to be able to test pH). It is corrosive if the pH is:

Less than or equal to 2, or
Greater than or equal to 12.5.

Solid corrosives are not common. Cement or lime, for example, are solids that may test as corrosive.

Frequently asked questions

The Biological Testing Methods for the Designation of Dangerous Waste publication includes two separate test procedures used to determine if a waste meets the definition of a state dangerous waste. Part A is the static acute fish toxicity test. Laboratories use a sample of solid waste to determine if it kills fish at a certain concentration, causing the waste to designate as a dangerous waste.

The fish toxicity test has been in use for over 40 years in Washington State, designed solely for the purpose of determining whether solid waste is a state dangerous waste based on toxicity. It does not include fish tissue testing and does not relate to human health criteria. The method measures mortality of juvenile salmon exposed to a waste mixture. The update to the test method changes test procedures to be more efficient for labs to use.

Part B included the acute oral rat toxicity test. This is an obsolete test which was removed from the publication in 2020.

Contact information

Need help?
Contact a dangerous waste inspector in your region.