Wisconsin's Public Liberal Arts College

Hazardous Waste Identification


Environmental Health and Safety

Hazardous Waste Identification

Wastes are defined as materials that are no longer suitable for their intended purpose. This includes materials that are waste products of a procedure, old outdated products that have not been used or new products purchased in excess. Hazardous wastes are solid, liquid or gaseous wastes with one or more of the characteristics listed below. Unless otherwise noted, the waste should be containerized and shipped for disposal.

  1. Corrosive: Any substance with a pH less than 2 or greater than or equal to 12.5. A corrosive waste with no other waste characteristic may be neutralized to a pH between 6 and 9 and sewered (Log date and Volume). Examples would include 5% nitric acid or an alkali such as sodium hydroxide.
  2. Ignitable: Any substance having a flash point less than 140°F (60° C), or any ignitable gas, or an oxidizer. Aqueous wastes containing 24% or less of an alcohol are not considered to be hazardous wastes. See the precautions on treatment in the introduction. Examples would include paint thinner, acetone, and potassium or ammonium dichromate.
  3. Reactive: Any unstable substance that can undergo rapid violent change, reacts violently with water, or is a sulfide or cyanide bearing material. Examples would include sodium or potassium cyanide.
  4. TCLP listed waste. A liquid mixture containing any of listed substances at or above the TCLP concentrations. If a solution contains a TCLP substance that is less than the Hazardous Waste regulatory limits but higher than the limits of the Municipal Sewer Code, it must be disposed of as a hazardous waste. Examples of a TCLP substance are silver, chromium or lead.
  5. Acutely Hazardous: Any material that has been found to be fatal to humans in low doses, or has an oral LD50 (rat) of less than 50 mg/kg, an inhalation LD50 (rat) or less than 2 mg/l, or a dermal LD50 (rabbit) of less than 200 mg/kg. Acutely hazardous wastes are found in NR605 Table IV. Examples would include potassium cyanide.
  6. It is a toxic waste. Any material listed in NR605 Table V. Examples would include formaldehyde.
  7. It is a listed waste from non-specific sources. Any material listed in NR605 Table II.

In general, all of the following substances used in our laboratories or studios should be disposed of hazardous waste: (this list is not complete)

  • Aqueous solutions, > 24% alcohol.
  • Cyanide-bearing wastes
  • Formaldehyde solutions, > 0.1%
  • Heavy metal salts and solutions
  • Oxidizing solutions
  • Sulfide-bearing wastes
  • Solvents
  • Chemicals labeled as toxic or poisons
  • Kerosene-saturated sawdust
  • Acid or base solutions

Sediment, soil, or other solid or aqueous materials that may have waste characteristics must be evaluated on a case-by-case basis.

Tables that identify the hazardous wastes in more detail are available from Carol Lindberg, Hazardous Materials Coordinator.


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