A. Defining Hazardous Waste

The Resource Conservation and Recovery Act (RCRA) defines what is and what is not a hazardous waste. Approximately 400 substances are "listed" by name in the regulations as hazardous waste. Other materials which meet the definition of one or more of the "characteristic" wastes are also regulated and must be properly disposed of. Under no circumstances should personnel dispose of waste down drains or the trash if they are unsure as to whether it is hazardous or non-hazardous.

  1. Characteristic Wastes - If a waste meets one or more of the following four "characteristics" it is considered a hazardous waste:
    • Ignitability
      • Liquids having a flashpoint of less than 140 degrees F (includes almost all organic solvents).
      • Materials that are not liquids and are capable of causing fire under standard temperature and pressure.
    • Corrosivity
      • Any aqueous material having a pH less than or equal to 2.0, or greater than or equal to 12.5.
      • All common organic and mineral acids are considered corrosives. Aqueous bases such as sodium hydroxide and potassium hydroxide have the characteristic of corrosivity.
    • Reactivity
      • Materials that are normally unstable and readily undergo violent change without detonating.
      • Materials that react violently with water or form potentially explosive mixtures with water or, when mixed with water form toxic vapors or fumes.
      • Materials that form hydrogen cyanide or hydrogen sulfide gas when exposed to pH conditions between 2 and 12.5.
      • Materials readily capable of detonation or explosive decomposition if subjected to a strong initiating source or is heated under confinement.
      • Materials that meet the definition of a Department of Transportation explosive.
    • Toxicity Characteristic Leaching Procedure (TCLP) Wastes\
      • Any waste product is considered "TCLP toxic" if it leaches any one of 40 named metals, solvents or pesticides in specific quantities.
      • The following chemicals are found under the Toxicity characteristic and are regulated in parts per million (ppm) concentrations: 

          u>Contaminant Regulatory Level (ppm)
          Arsenic 5.0
          barium 100.0
          Cadmium 1.0
          Chromium 5.0
          lead 5.0
          Mercury  0.2
          selenium 1.0
          silver 5.0
          benzene 0.5
          carbon tetrachloride 0.5
          chlorobenzene 100.0
          chloroform 6.0
          cresol 200.0
          Lindane 0.4
          methyl ethyl ketone 200.0
          nitrobenzene 2.0

        Many metals are toxic to humans and aquatic life in very low concentrations. Metals are a persistent problem because they cannot be broken down into less toxic materials. The Borough of Huntingdon regulates disposal of additional metals which are not on the RCRA list, including copper, nickel, and zinc.
  2. Listed Wastes - Some chemicals are RCRA regulated wastes because they are found on a list (U & P listed). The U & P listed wastes can be found in Appendix B and Appendix C, respectively. In addition, some chemicals are listed RCRA regulated wastes because they are generated from either a specific or a non-specific source (K & F listed).
    • U and P listed wastes are chemicals which are regulated by RCRA if they are unused commercial products, off-specification species, spill residues, and all formulations containing the chemical as the sole active ingredient. P-listed wastes are acutely hazardous chemicals which are extremely toxic to humans. P-listed wastes include chemicals such as sodium azide, osmium tetroxide, and potassium cyanide. Empty containers which once held a P-listed chemical must be triple rinsed with an appropriate solvent before being considered a non-regulated waste. U-listed wastes are chemicals which are toxic to humans. U-listed wastes include chemicals like chloroform, phenol, and acetonitrile. Empty U-listed waste containers do not have to be rinsed; however all the material must have been removed (by normal pouring or scraping).

B. Collection, Labeling and Containment

  1. Laboratory supervisors are responsible for the safe collection and temporary storage of hazardous wastes generated in their laboratory.
  2. Waste must be stored in closed containers at or near the point of generation. Such "satellite storage areas" are limited by federal regulations to a maximum volume of one quart of P-listed waste. It is important that the one quart limit of P-listed wastes is not exceeded and that P-listed wastes are not mixed with larger volumes of other materials.
  3. Hazardous waste containers must be labeled with the words "Hazardous Waste" and a list of constituents present in amounts > 1.0% (0.1% for Particularly Hazardous Substances).
    Note: in certain circumstances, the contents of a container may be noted on a separate sheet maintained near the accumulating container; this is practical when small amounts of many different materials are placed into one container.
  4. The identity of the contents in the container must be in the form of the chemical name and not a chemical formula; no abbreviations should be used. Any manufacturer labels present on the container must be completely removed or completely obscured.
  5. Containers of liquid waste must include provision for secondary containment in the event of a leak or spill. Bottles and other containers housing waste must be kept closed except when filling. Bottles should not be filled completely: leave about 5% of the capacity of the bottle empty to provide room for expansion. Evaporating waste (aqueous or organic) to reduce the quantity is not permitted under any circumstances.
  6. Solid chemical waste can be collected in plastic bags or plastic containers. Solid waste containers must be sealed.
  7. Chemical waste must be collected in a chemically compatible container. 

C. Segregation of Wastes  

  1. Segregation of chemical waste is necessary so that waste can be safely collected and disposed. Chemical waste must be segregated in such a manner that only chemically compatible wastes are mixed together.

    In general, segregate solids from liquids, and organics from inorganics.

    It is important to also segregate:

    • Halogenated from non-halogenated solvents.
    • Strong acids from bases.
    • Sulfides or cyanides from acids.
    • Particularly hazardous substances from all other waste classes.
  2. Caution and common sense must be used when collecting chemical waste in the laboratory so that incompatible materials are not mixed together. Empty waste containers should be properly rinsed if they held a material which is incompatible with the waste to be collected. All chemicals should be handled with respect and every effort made to understand their chemical, physical and toxic properties prior to working with them.


D. Prohibited Materials

Some waste products are not allowed in the chemical waste stream because of regulatory compliance issues. Please segregate the following materials from chemical waste streams:

  • Asbestos
  • Infectious Waste (see Juniata's Infectious Waste Protocol)
  • PCB's (polychlorinated biphenyls)
  • Radioactive Materials
  • Uranium Compounds (uranyl acetate and uranyl nitrate)

E. Sewer Disposal Guidelines

In general, Juniata prohibits the disposal of chemical waste into the sanitary sewer; such disposal is regulated by the Clean Water Act. The following guidelines must be followed whenever considering disposing of chemicals into the sewer:

  1. The sanitary sewer shall be used only for the disposal of small quantities of non-toxic buffer solutions and non-hazardous chemicals. In many cases, toxic chemicals cannot be present in concentrations greater than 1 ppm (note: a 1% solution is 10,000 ppm in concentration).
  2. Waste must be water soluble.
  3. Flammable liquids are not allowed into the sanitary sewer. This includes most organic solvents.
  4. Do not dispose of corrosive waste (acidic or basic) into the sewer.
  5. Toxic, heavy metals are stringently regulated.  Do not dispose of these substances in sinks or drains.
  6. Waste cannot contain a large amount of highly concentrated colored dyes.  Do not discard expired dyes or concentrated stock solutions into the sewer.
  7. Waste cannot be either a carcinogen or highly toxic. 
  8. Do not dispose of infectious materials in sinks or drains without prior disinfection with an appropriate disinfectant.
  9. Although most chemical waste cannot be disposed of into the sewer and must be disposed of as hazardous waste, the following is a list of chemical waste that is acceptable for sewer disposal in quantities of 5 gallons or less:
    Organic Chemicals Sink Approved:
    • Acetates: Na, K, Ca, and NH4
    • Alcohols: water soluble, 20% or less concentration
    • Amino acids and their salts
    • Citric acid and salts of Na, K, Mg, Ca, and NH4
    • Ethylene glycol: concentrations of 10% or less
    • Lactic acid and salts of Na, K, Mg, Ca, and NH4
    • Sugars: dextrose, fructose, glucose, sucrose

    Inorganic Chemicals Sink Approved:
    • Common acids and bases: neutralized as part of your experimental protocol, no metals present
    • Bicarbonates: Na, K
    • Bleach
    • Bromides: Na, K
    • Buffer Solutions: Non-toxic w/0.1% or less sodium azide
    • Carbonates: Na, K, Mg, Ca
    • Chlorides: Na, K, Mg, Ca
    • Iodides: Na, K
    • Phosphates: Na, K, Mg, Ca, NH4
    • Sulfates: Na, K, Mg, Ca, NH4

F. Waste Minimization

Some of the things that can be done to minimize the amounts of hazardous waste generated include:

  1. Minimize intake: use only the smallest amounts possible to perform an experiment,
  2. Recycle whenever possible, and
  3. Find less hazardous, less toxic, alternative materials to use whenever possible.