Step four: What are the hazards (characteristics)?

Waste characteristics are measurable, physical characteristics that might make your waste hazardous to you or the environment. Once you determine if your waste designates for any listed codes — K, F, P, or U — you will need to determine its characteristic hazards.

The four groups of characteristic hazards are:

  • Ignitable (D001).
  • Corrosive (D002).
  • Reactive (D003).
  • Toxic (D004 to D043).

Dangerous waste characteristics

Learn more about dangerous waste characteristics (WAC 173-303-090).

Ignitable: Code D001

Ignitable wastes easily catch fire and continue to burn for a long time. Ignitable wastes have a D001 code.

  • Ignitable liquid wastes have a flashpoint of 140 degrees F or less.
  • Ignitable solids catch fire and burn vigorously through friction, absorption of moisture, or spontaneous chemical changes.
  • Compressed gases and oxidizers are also classified as ignitable under certain conditions.

Corrosive: Code D002

Corrosive wastes are acids or bases that are capable of corroding metal containers, such as storage tanks, drums, and barrels. They can seriously damage skin, lungs, and other tissue. These wastes have a D002 code.

A liquid is corrosive if it:

  • Has a pH less than or equal to 2, or
  • Has a pH greater than or equal to 12.5, or
  • Corrodes steel at a specified rate.

Bleach and battery acid are common examples.

A solid or semisolid is corrosive if it:

  • Has a pH of less than 2, or
  • Has a pH greater than 12.5.

Solid corrosives are also a Washington state-only waste with the waste code WSC2.

Reactive: Code D003

Reactive wastes are unstable under "normal" conditions. They can cause explosions, toxic fumes, gases, or vapors when heated, compressed, or mixed with water. These wastes have a D003 code.

Examples include:

  • Lithium-sulfur batteries.
  • Explosives.

Toxic: Codes D004 to D043

Toxic wastes are harmful or fatal when ingested or absorbed. When toxic wastes are land-disposed, contaminated liquid may leach from the waste and pollute groundwater. There are 40 chemicals on the federal toxicity characteristic list (the “D list”) (see WAC 173-303-090(8)(c)), each with a unique waste code. If your waste contains one of these 40 chemicals at a concentration equal to or greater than the threshold level, you must use the waste code that corresponds with that chemical.

Examples include:

  • Heavy metals.
  • Pesticides.
  • Organic chemicals.

The Toxicity Characteristic Leaching Procedure (TCLP) is a laboratory test that measures the likelihood toxic chemicals will leach out of a waste in landfill conditions. If the waste exceeds threshold TCLP levels for characteristic chemicals, the waste is a dangerous waste. Learn how to choose an analytical laboratory to test waste.