Washington state-only criteria

In Washington, businesses must designate their waste to see if it meets Washington state-only criteria. This is in addition to the first four steps of waste designation. Designating for Washington state-only criteria is considered steps 5 through 7 of the waste designation process.

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Who must designate for Washington state-only criteria?

The following generators must designate for Washington state-only criteria:

Generators with waste that does NOT designate as listed waste or characteristic waste.
Small quantity generators (SQGs) with listed or characteristic waste (proceed to step 5 ONLY).

Medium and large quantity generators (MQGs and LQGs) with listed or characteristic waste are NOT required to designate for Washington state-only criteria.

Step 5: Washington state-only toxic waste

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

WT01 is for waste that meets specific toxicity concentrations (WAC 173-303-100). WT01 waste counts toward the 2.2 pound quantity exclusion limit (QEL) because it is a toxic extremely hazardous waste.
WT02 is for waste that has lower toxicity than WT01 waste but still surpasses a concentration threshold (WAC 173-303-100).

Use one of the following methods to determine if your waste is considered a Washington state toxic:

Book designation, using published toxicity data, or
Fish bioassay.

If you know all the toxic substances in your waste, you can calculate if your waste is state-only toxic.

You must know:

The identity and concentration of each hazardous substance.
The lethal dose or lethal concentration of each hazardous substance or both.

How to calculate state-only toxic

To calculate if your waste is state-only toxic:

Use the Toxic Category Table (WAC 173-303-100(5)(b)(i)) to determine the toxic category of substance.
Determine the equivalent concentration (WAC 173-303-100(5)(b)(ii)). WT01 wastes have an equivalent concentration equal to or greater than 1%. WT02 wastes have an equivalent concentration less than 1% but greater than 0.001%.

How to find lethal dose or lethal concentration

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:

What if there are multiple toxicity values?

If there are multiple toxicity values, such as lethal dose (LD50) or lethal concentration (LC50) for fish, oral-rat, inhalation-rat, or dermal-rabbit, then 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.

How to find identity and concentration

Most information about the hazardous substances can be found with the following:

Safety Data Sheets (SDSs)
Understanding reaction, concentration, or dilution effects associated with the production process

To better understand your waste’s composition, you can send a representative sample of your waste to an analytical lab to test for the concentration of suspected hazardous substances.

Analytical testing using a fish bioassay offers a more accurate determination of toxicity. This method requires that you send a representative sample to an alytical laboratory to test if it kills fish at certain concentrations.

You can choose to do both book designation and fish bioassay. If the designation acquired from book designation and bioassay data don’t agree, then bioassay data will be used to designate waste.

Read our Biological Testing Methods for the Designation of Dangerous Waste for more information.

Step 6: Washington state-only persistent wastes

Persistent wastes have chemicals that are slow to break down, linger in the environment, and can accumulate in living tissue. There are two types of persistent wastes to designate:

Polycyclic aromatic hydrocarbons (PAHs)
Halogenated organic compounds (HOCs)

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

Bromine
Chlorine
Fluorine
Iodine bonded directly to a carbon atom

NOTE: Halogenated polymers, such as polyvinyl chloride (PVC), are NOT considered persistent dangerous waste.

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

WP01 is for waste with an HOC concentration greater than 1% (10,000 ppm).
WP02 is for waste with an HOC concentration less than 1% and greater than 0.01% (100 – 10,000 ppm).

Step 7: Washington state-only PCB or special waste

There are three categories of waste to designate in this step:

Waste polychlorinated biphenyls (PCBs)
Solid corrosives
Special wastes

Waste with polychlorinated biphenyls (PCBs) greater than or equal to 2 parts per million (ppm) and less than 50 ppm may be state-only dangerous waste (coded WPCB). Waste PCBs are defined in the WPCB code (WAC 173-303-9904) as:

Transformers, capacitors, or bushings that contain PCB fluids with concentrations greater than or equal to 2 ppm, unless they are drained of all free-flowing liquid.
All wastes containing PCBs greater than or equal to 2 ppm generated from salvaging, rebuilding, or discarding transformers, capacitors, or bushings.

Can PCB wastes be excluded?

Yes. See our Polychlorinated Biphenyl Dangerous Waste Guide for more information.

Special waste poses a relatively low hazard to human health and the environment. If your waste meets specific designation criteria, you can choose to manage the waste under the conditional exclusion requirements or as fully regulated dangerous waste. See our Focus on: Special Waste Exclusion for information on the designation criteria and requirements.

Examples of potential special wastes include:

Lye contaminated absorbents and debris.
Pollution control filter cake.
Dried paint.
Metal machining wastes.

Contact information

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