The Hazardous Waste Determination: Is my chemical waste a ‘hazardous waste’?

The process for determining if your chemical waste is a ‘hazardous waste’ is called a waste determination. Waste determinations can be made in one of two ways:

  1. Through collecting a sample of the waste and sending it for analysis, or
  2. Exercising knowledge of the chemical and processes which generated it to determine whether or not it is a hazardous waste. MSDS sheets are useful in these determinations.

For laboratory operations it usually possible to use chemical and process knowledge to make an accurate waste determination. Contact EHSEnvironmental Health & Safety for help in making waste determinations.

Test #1: Characteristic Hazardous Wastes

Your chemical waste is a hazardous waste if it exhibits any of the following characteristics:


  • Liquids with flash point < or = 140 F
  • Solids which can ignite via friction or reaction
  • Flammable gases
  • Strong oxidizers

Examples: Alcohols, solvents, stains and mixtures containing these materials


  • Liquids with a pH: ≤ 2.0 ≥ 12.5

Examples: Acids and bases


  • Unstable materials
  • Reacts violently with water or air
  • Cyanide or sulfide which can generate toxic gases.

Examples: Alkali metals, silanes, azide compounds, sodium cyanide


  • Wastes bearing the metals:
    • Arsenic
    • Barium
    • Cadmium
    • Chromium
    • Lead
    • Mercury
    • Selenium
    • Silver
  • Halogenated organics
  • Oil

Examples: Hg-preserved antibodies, chloroform, vacuum pump oil, photo fixer

Test #2: Listed Hazardous Wastes

Your chemical waste is a hazardous waste if it exists on a state or federal list of hazardous wastes:

  • F List: containing 10% or more (before use) of halogenated and non-halogenated solvents such as: trichloroethylene, methylene chloride, carbon tetrachloride, chlorobenzene, xylene, acetone, ethyl acetate, ethyle benzene, methanol, ethyl ether, cresols, nitrobenzene, toluene, MEK, carbon disulfide, pyridine, benzene …
  • U List: Only applies to chemicals that are 1) unused and 2) sole active ingredients. We don’t often generate U-listed materials because we don’t often generate wastes that are ‘unused.’
  • P List: The P-list is for‘acutely hazardous’ chemical wastes. It is important because if a chemical is on the P-list both the waste chemical AND the empty container must be collected as hazardous waste. Some common examples of P-listed wastes are: sodium azide, acrolein, oxides of arsenic, benzyl chloride, carbon disulfide, nicotine, nitroglycerin, phenylthiocarbamide, proprionitrile …


  • Treating hazardous wastes to render them non-hazardous is NOT an option (dilution, neutralization, etc.)
  • Mixing hazardous waste chemicals with other materials results in the entire mixture becoming hazardous waste
  • Any time a hazardous waste is spilled, all disposable materials (pads, towels, gloves, etc.) used in the cleanup process become hazardous waste.

This guide is intended as a quick reference. Contact EHS for more complete information.

CRCCharles River Campus: 353-4094
BUMCBoston University Medical Campus: 638-8830
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