Environmental Health & Safety Hazardous Materials / Wastes

Waste Identification Guide


By following the methods outlined in this section, laboratory and departmental personnel can determine if waste or surplus chemicals meet the definition of regulated waste. All chemicals found to be regulated must be managed through Environmental Health & Safety (EH&S).

After identifying chemicals, personnel may enter all applicable waste designation codes on the Chemical Collection Request forms sent to EH&S.

Assistance: If the responsible person requires assistance with identifying or designating wastes, he or she may contact EH&S; telephone 335-3041.


Responsible Individual: The individual in charge of the laboratory or workplace where waste or surplus chemicals are generated is responsible for determining whether chemicals are regulated dangerous wastes or not. This individual may be a principal investigator, research leader, instructor, shop supervisor, or unit administrator.

Scientific Name: To identify a waste chemical, determine the scientific name of the substance (or scientific names if a mixture). If the scientific name is not on the label of the waste container, refer to the Material Safety Data Sheet (MSDS). Scientific names of chemicals are required to be present on a MSDS which identifies a trade-name chemical.

Lists, Characteristics, Criteria: To designate a waste as a regulated waste, determine whether the waste

  • is present on one of the lists of hazardous or dangerous chemicals,
  • has the characteristics of a hazardous waste
  • meets certain criteria which make the substance a hazardous waste.

First check the lists, then review the characteristic and criteria parameters.

Lists: Compare the chemical name(s) with the lists. If the chemical name appears on a list it is a regulated waste.

If the chemical name does not appear on any of the lists, the substance may still be a regulated waste.

Characteristics: A substance must be managed as a dangerous waste if it shows characteristics of ignitability, corrosivity, reactivity, toxicity, or if the substance is an oxidizer as described in the dangerous waste regulations.

If the chemical name does not appear on any of the lists or if the chemical does not have waste characteristics, the substance may still be a dangerous waste.

Criteria: If the substance meets state criteria for toxicity or persistence the substance must be managed as a dangerous waste.

Not Dangerous Waste: If the waste does not meet any of the state criteria or federal characteristics, and is not present on a waste list, it is not a regulated waste and may be discarded using other waste disposal options.


Acutely Hazardous Waste: Some Extremely Hazardous Waste(EHW) is considered to be “acutely hazardous waste“by both state and federal agencies. Acutely hazardous waste can be accumulated in a waste generation area only in quantities up to one quart before it must be removed, within three days, to a 90-day accumulation area.

Hazardous Waste: A general term applied to any chemical waste.

NOTE: Federal regulations define hazardous waste as chemical waste only; radioactive and biological wastes are not specified in the federal regulations.

Waste Generation Area: A waste generation area is a room, a portion of a room, a group of interconnected rooms, or an outdoor site where regulated dangerous wastes are created.

EPA Lists and Characteristics

Waste Lists

  1. Acutely Hazardous Wastes (P codes)
  2. Dangerous Wastes (U codes)
  3. Dangerous Waste Sources (F and K codes)
  4. Toxicity Characteristics (D codes)
    NOTE: These are large lists and may load slowly.

NOTE: F-listed wastes are common at WSU but K-listed wastes are rarely generated by University activities.

Waste Characteristics

For chemicals which are not on these lists, EPA has definitions of “characteristics” of non listed hazardous wastes.If a surplus or waste chemical meets those characteristics, it must be managed as a hazardous chemical waste. These characteristics are identified by the terms ignitability, corrosivity, reactivity,and toxicity.

Ignitability (D001): If the waste chemical meets the ignitability characteristic as indicated below it is a dangerous waste and carries the D001 waste code.The following definition is from WAC 173-303-090(5).

NOTE: “Ignitable” substances include flammable liquids,flammable solids, flammable gases, and oxidizers.

  1. Flammable liquid is defined as a non-aqueous solution which has a flash point of less than 60 degrees C. (140 degrees F.)as measured by a Pensky-Martens Closed Cup Flash Tester utilizing a specific method.
  2. flammable liquid is also defined as an aqueous solution containing more than 24% alcohol which has a flash point of less than 60 degrees C. (140 degrees F.) as measured by a Pensky-Martens Closed Cup Flash Tester utilizing a specific method.
  3. Flammable solid is defined as any material which is not a liquid at standard temperature and pressure, and which may ignite as a result of friction or the absorption of moisture, or which may ignite spontaneously.
  4. Flammable gas is defined according to 49 CFR 173.300, as “a compressed gas” in which “any one of the following occurs”:
    1. Either a mixture of 13% or less (by volume) with air forms a flammable mixture or the flammable range with air is wider than 12% regardless of the lower explosive limit (tested using a specified method).
    2. When igniting the gas at the valve, the flame projects more than 18 inches beyond the ignition source with the valve opened fully, or, the flame flashes back and burns at the valve with any degree of valve opening (tested using a specified method).
    3. There is any significant propagation of flame away from the ignition source (tested using a specified method).
    4. There is any explosion of the vapor-air mixture in a drum (tested using a specified method).
    5. Oxidizer is defined as “a substance such as a chlorate, permanganate, inorganic peroxide, or a nitrate, that yields oxygen readily to stimulate the combustion of organic matter.” Oxidizer is also defined as “an organic compound containing the bivalent-O-O- structure and which may be considered a derivative of hydrogen peroxide where one or more of the hydrogen atoms have been replaced by organic radicals”, unless the material is classified as an explosive, forbidden for transportation, or it is determined that the predominant hazard of the material containing the organic peroxide is other than that of an organic peroxide.

Corrosivity(D002): If the chemical meets the corrosivity characteristic as indicated below it is a dangerous waste and carries the D002 waste code. The following definition is from WAC 173-303-090(6).

Corrosive is defined as:

  1. An aqueous solution which exhibits the characteristic of pH less than or equal to 2 or greater than or equal to 12.5.
  2. Any material which corrodes steel (SAE 1020) at a rate of 0.250 inches per year at 55oC.(130oF.).
  3. Any solid or semi-solid material which, when tested using a specified procedure exhibits a pH less than or equal to 2 or greater than or equal to 12.5.*
    *Any waste that exhibits the characteristic of corrosivity due only to #3 above will be designated DW and assigned the waste number WSC2.

NOTE: The City of Pullman has discharge limits that are much more stringent than those outlined above. The pH of any substance poured down the drain must be between 6 and 9. For additional requirements, contact EHS.

Reactivity (D003): If the waste meets the reactivity characteristic as indicated below it is a dangerous waste and carries the D003 waste code. The following definition is from WAC 173-303-090(7).

A reactive:

  1. reacts violently upon contact with water, or produces toxic or explosive gases upon contact with water, or
  2. is cyanide or sulfide bearing and when exposed to solution of pH less than 2 or greater than 12.5 produces toxic vapors, or
  3. is capable of detonation or explosion, or
  4. iIs classified as a Forbidden Material (49 CFR 173.51), Class A Explosive (49 CFR 173.53), or Class B Explosive (49 CFR 173.88) by the U.S. Department of Transportation.

Toxicity Characteristics (D004-D043): The toxicity characteristics waste list is used to control wastes with toxic characteristics. Chemicals on this list have “D” prefixes. (WAC 173-303-090(8)(c)) If a waste or any constituent of a waste mixture is on the Toxicity Characteristic list, it carries the applicable D code.

Washington State Waste Criteria

Waste Criteria

Washington rules are more restrictive than the federal rules governing waste management. Therefore, certain kinds of waste are regulated at the state level but not at the federal level.

The state of Washington adopted EPA’s categories and added another set of waste definitions called criteria wastes.

Criteria wastes are also identified by four digit codes, but these codes begin with the letter “W.” A second letter is added to describe the particular “criteria”, and two numbers following the two letters describe specific types of “criteria.”

The state of Washington defines two “criteria” waste types:

  1. Toxicity, with waste codes WT01 and WT02,
  2. Environmental persistence, with waste codes WP01, WP02, and WP03

If the chemical meets criteria as described below, it must be managed as a dangerous waste. (WAC 173-303-100,)

NOTE: There is a federal characteristic of toxicity which categorize chemical wastes as dangerous waste. In addition, there is a state criteria of toxicity which categorizes chemical wastes as dangerous waste.

Toxicity(WT01, WT02): If the waste meets the toxicity criteria as indicated below it is a dangerous waste. Refer to the following table to determine whether the chemical meets toxicity criteria. These criteria are from WAC 173-303-100.

Toxic Category Table

CategoryTLm 96 (Fish) or Aquatic LC 50 ppmOral (rat) LD 50 (mg/kg)Inhalation (rat) LC 50 mg/LDermal (Rabbit) LD 50 (mg/kg)Washington State Waste Code
X< .01="">< .5="">< .02="">< 2="">WT01
A.01 - .1.5 - 5.02 - .22 - 20WT01
B.1 - 15 - 50.2 - 220 - 200WT01
C1 - 1050 - 5002 - 20200 - 2000WT01
D10 - 100500 - 500020 - 2002000 - 20000WT02

To determine if a mixture of chemicals is a waste based on toxicity, find the Toxic Category (X,A,B,C, or D) for each chemical in the mixture, and use their percent concentrations in this formula:

Equivalent Concentration (EC)=sum(X)% + sum(A)%/10 + sum(b)%/100 + sum(C)%/1000 + sum(D)%/10000 where sum(X, A, B, C, or D)% is the sum of all the concentration percentages for a particular toxic category.

For example, a waste contains: .01% Aldrin (category A), 1% Endrin (Category C), 5% benzene (category C), 10% phenol (category C), and 83.99% water (nontoxic).

The EC would be:

EC=.01% + 0%/10 + 1%/100 + (5% + 10%)/1000 + 0%/10000
EC=.01% + 0% + .01% + .015% + 0% = .026
Equivalent Concentration equals .026%

The waste may then be designated based on the equivalent concentration.

If your EC is...Then your waste's designation is...State Waste Code
<>Not a Dangerous WasteNone Apply

Persistence(WP01, WP02, WP03): If the waste meets the persistence criteria as indicated in the table below, it is a dangerous waste. Persistent wastes contain either halogenated organic compounds or polycyclic aromatic hydrocarbons (PAH, containing 2 or more fused benzene rings). The following table is from WAC 173-303-100.

Persistence Waste Table

If your waste contains...At a concentration of...Then your waste's designation is...State Waste Code
Halogenated Organic Compounds (HOCs)greater than 1.0%EHWWP01
Halogenated Organic Compounds (HOCs)0.01 to 1.0%DWWP02
Polycyclic Aromatic Hydrocarbonsgreater than 1.0%EHW*WP03

*  No DW concentration level for PAH

Polychlorinated Biphenyl (PCB) Waste (W001): The state of Washington regulates as dangerous waste any PCB-contaminated waste containing 2 parts per million (ppm) PCB or greater.

Washington State University