Hazardous waste characterization


Framework for the Resource Conservation and Recovery Act

It is important to know the correct classification of all of the organization's waste, as different sets of rules will apply to the facility depending on the total amounts of each type of hazardous waste generated per year. Large quantity generators (LQGs) operate under more stringent rules and more comprehensive reporting requirements than small quantity generators (SQGs). The following information will assist healthcare organizations in determining what to count toward their hazardous waste totals.

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Once the organization has determined the types and amounts of hazardous waste generated per year, it will be able to find which rules apply to the facility by checking out the Healthcare Environmental Resources Center's (HERC) webpage on "Managing Hazardous (RCRA) Wastes". Please note that state regulations may be more stringent than the federal regulations. Consult the HERC State Hazardous Waste Locator to find more information on an individual state's hazardous waste regulations.

There are two primary ways that a waste material can become classified as a hazardous waste, subject to the EPA's Resource Conservation and Recovery Act (RCRA) requirements:

  • Listed wastes: Wastes from certain industrial processes are automatically classified as hazardous. Each waste of this type is given a code number. The full list of hazardous waste codes appears in the Code of Federal Regulations, 40 CFR 261.
  • Characteristic wastes: Wastes that do not appear on the CFR lists may nevertheless be classified as hazardous if they have one of four properties:
    • ignitability
    • corrosivity
    • reactivity
    • toxicity

In addition, materials can acquire hazardous waste status if they are mixed with, or contaminated with, or are derived from, other wastes that are themselves hazardous. The generator of the waste is responsible for determining if the waste is hazardous. The rules can get complicated. In addition to determining whether a waste is hazardous, the organization will need to know how each particular waste is classified. The rules that apply to a particular facility will depend on how much waste, and what type of waste it generates. Misclassifications can (and do) lead to citations and penalties.

Listed Waste

The RCRA regulations include four lists of materials, designated with the letters F, K, P, and U. If the active ingredient of waste product the organization is evaluating appears on the any of the four lists, the material is likely a hazardous waste but may need additional screening for verification of its HW status. The P- and U-lists, for example, do not apply to manufactured articles that contain a P- or U-listed waste (e.g. mercury thermometers) or to products that contain more than one active ingredient. Such wastes might still be hazardous, but their hazard classification would fall under a different category (most likely the toxicity characteristic discussed below).

What distinguishes the lists?

The F- and K-lists cover process wastes.The P and U-lists cover unused chemicals that are being discarded for various reasons; for example, they may be off-specification or expired, they may have been spilled and cleaned up, or they may be residues left in containers.

The distinction between the two process waste lists (F and K) lies in their specificity. The K-list deals with very specific processes that are typically carried out by one manufacturing sector only, such as organic chemical manufacturing or petroleum refining. The F-list covers general processes that might occur in a range of sectors, such as solvent use, metal finishing processes, and wood preserving.

The unused chemicals lists (P and U) differ in their degree of risk. P-listed wastes are "acutely toxic", meaning that they can cause death or irreversible illness at low doses. U-listed wastes are "toxic": they are still regarded as hazardous, but some of the more stringent regulations that apply to the P-list do not apply to U-listed wastes.


Healthcare facilities do not carry out manufacturing processes, and would not typically generate any K-listed materials.


The first five F-listed categories, F001 - F005, cover a range of solvents used in a variety of applications.  A healthcare facility might generate F-listed solvents such as acetone, methanol, toluene, xylene, and methylene chloride from departments such as:

  • Pathology laboratory
  • Histology laboratory (xylene)
  • Pharmacy
  • Morgue
  • Maintenance shops (degreasers)

The rest of the F-list is not likely to apply to healthcare facilities.


If the organization is interested in reducing the hazardous waste it generates, eliminating or finding substitutes for P-listed chemicals is a good place to start. A small quantity -one kilogram- of a P-listed waste can cause a facility to be classified as a "large quantity generator," and to have to comply with more stringent rules as a consequence.

The P-List includes about 239 different "acutely toxic" substances, listed under about 135 different waste codes. (Some codes cover several substances.) Practice Greenhealth has identified 15 of these that you might expect to find in a healthcare facility. They are listed below, along with their waste codes and typical uses associated with each. The CAS numbers for these compounds can be found in the official list at 40 CFR 216.33.

**Please note that the short list below is not meant to be exhaustive, and also that states may impose restrictions that apply to wastes beyond those listed in the federal list.

P-listed Chemicals Commonly Found in Healthcare Facilities


Code Use
3-benzyl Chloride P028 pharmaceutical manufacturing
Arsenic P012 veterinary medicine, severe parasitic diseases
Arsenic Trioxide P012 chemotherapy
Chloropropionitrile P027 pharmaceutical synthesis
Cyanide Salts P030 laboratory
Epinephrine P042 emergency allergy kits, certain types of glaucoma, eye surgery, cardiac arrest
Nicotine P075 smoking cessation, nicotine patches, etc.
Nitroglycerin P081 coronary vasodilator in angina treatment
Phentermine P046 appetite suppressant
Phenylmercuric acetate P092 bactericide, pharmaceutic aid in contact lens solutions and nasal sprays
Physotigmine P204 acholinergenics (liberates/acts like acetylcholine)
Physotigmine Salicylate P188 acholinergenics (liberates/acts like acetylcholine)
Potassium Silver Cyanide P099 bactericide
Sodium Azide P105 chemical preservative in hospitals, laboratories
Strychnine P108 veterinary tonic and stimulant

Special note on sodium azide (P105) Sodium azide, found in Enterococcus agars, is also used in detonators and other explosives. An odorless white solid, it is a rapidly acting, potentially deadly chemical. It changes rapidly to a toxic gas with a pungent (sharp) odor when it is mixed with water or an acid, or when it comes into contact with certain metals (for example when it is poured into a drain pipe containing lead or copper). But the odor of the gas may not be sharp enough to give people sufficient warning of the danger. Please note that serious accidents have occurred in laboratory settings. In one case, when sodium azide was poured into a drain, it exploded and the toxic gas was inhaled.


The U-List includes about 472 distinct materials, listed under about 247 different waste codes. (As with the P-list, the same code can refer to several different materials.) Practice Greenhealth has identified 66 of them that you might expect to find in a healthcare setting, and has listed them, along with their waste codes and typical uses, below. The CAS numbers for these compounds can be found in the official list at 40 CFR 216.33.

This list is not meant to be exhaustive. Be aware that states (particularly WA and MN) may impose restrictions that apply to wastes beyond those listed in the federal list.

U-listed chemicals commonly found in healthcare facilities



Code Use
Acetone U002 solvent in pharmaceutical formulations
Acetyl Chloride U006 cholesterol testing
Acrylonitrile U009 pharmaceutical manufacturing
Aniline U012 pharmaceutical manufacturing
Azaserine U015 antifungal, antineoplastic
Benzidine dichloride U243 pathology laboratory
Bromoform U225 sedative, hypnotic, antitussive
Cacodylic Acid U136 dermatologic
Carbon Tetrachloride U211 anthelmintic, pharmaceutical formulations
Chloral Hydrate U034 cough syrups, sleeping pills
Chlorambucil U035 chemotherapy
Chlornaphazin U026 antineoplastic
Chloroform U044 anesthetic
Creosote U051 antiseptic, expectorant
Cresols U052 antiseptics, disinfectants
Cyclophosphamide U058 chemotherapy
Daunomycin U059 chemotherapy
o-Dichlorobenzene U070 germicides, pharmaceutical manufacturing
m-Dichlorobenzene U071 germicides, pharmaceutical manufacturing
p-Dichlorobenzene U072 germicides, pharmaceutical manufacturing
Diethylstilbestrol U089 anticancer agent, contraceptive
Ethyl Acetate U112 drug flavoring agent, topical anesthetic
Ethyl Carbamate U238 antineoplastic
Ethyl Ether U117 disinfectant, anesthetic
Ethylene Oxide U115 high level sterilant for surgical instruments
Formaldehyde U122 antiseptic, disinfectant, preservative
Formic Acid U123 diuretic, heart and muscle treatment
Hexachloroethane U131 anthelmintic (anti-worm treatment)
Hexachlorophene U132 skin treatment ( pHisoHex, Septisol)
Hexachloropropene U243 dialysis, pesticide (Septisol foam?) *
Lindane U129 scabicide
Melphalan U150 chemotherapy
Maleic Anyhydride U147 pharmaceutical manufacture
Mercury U151 preservatives (thimerosal), antiseptics (mercurochrome), devices (thermometers, sphygmomanometers, others)
Methanol U154 solvent in pharmaceutical manufacture
Methylpyrilene U155 antihistamine
Methylthiouracil U164 thyroid inhibitor
U010 chemotherapy
Naphthalene U165 antiseptic, anthelmintic
N-butyl alcohol U031 bactericide, pharmaceutical manufacture, pain control, anti-hemorrhagic
P-Chloro-m-Cresol U039 antiseptic
Paraldehyde U182 sedative, hypnotic
Phenacetin U187 analgesic, antipyretic
Phenol U188 antiseptic, anesthetic, antipruritic (relieves itching)
Reserpine U200 hypertension, insanity, snakebite, cholera, horse tranquilizer
Resorcinol U201 acne, dandruff treatment, intermediate in pharmaceutical synthesis
Saccharin U202 sugar substitute, food preparation
Selenium sulfide U205 shampoos
Streptozotocin U206 chemotherapy
Tetrachloroethylene U210 anthelmintic
Uracil mustard U237 chemotherapy
Thiram U244 antiseptic
Trichloroethylene U228 inhalation anesthetic, pharmaceutical manufacture
Warfarin < 0.3% U248 anticoagulant
2-Chloroethyl Vinyl Ether U042 anesthetics and sedatives manufacture
3-Methylchloranthrene U157 cancer research

Chemotherapy agents

Many of the chemicals used to treat cancer patients during chemotherapy fall on either the U or P lists. These agents are often referred to by their brand names rather than the chemical designations appearing on the lists.  For convenience, Practice Greenhealth has listed some common brand names below, together with their chemical names and RCRA waste codes. Since new products may be introduced at any time, this list may not include all brand names composed of RCRA listed chemicals.

Brand name Chemical Name Code
Alkeran Melphalan U150
Cerubidine Daunomycin U059
CTX Cyclophosphamide U058
Cytotoxan Cyclophosphamide U058
Daunorubicin Daunomycin U059
DaunoXome Daunomycin U059
Leukeran Chlorambucil U035
Liposomal Daunorubicin Daunomycin U059
L-PAM Melphalan U150
Mitomycin Mitomycin C U010
Mutamycin Mitomycin C U010
Neosar Cyclophosphamide U058
Procytox Cyclophosphamide U058
Rubidomycin Daunomycin U059
Streptozocin Streptozotocin U206
Trisenox Arsenic Trioxide P012
Zanosar Streptozotocin U206

*Note that while most chemotherapy agents are U-listed, arsenic trioxide is P-listed.

In addition to these brand names, the organization may utilize various other listed drugs hat are used in cancer research or treatment, though they have not been FDA-approved for general use.  Examples include:

  • Azaserine U015
  • Chlornaphazin U026
  • Ethyl Carbamate U238
  • 3-Methylchloranthrene U157

Other chemicals may be added to the RCRA lists at some point in the future.  In any case, even if some of the chemotherapy agents in the facility are not currently included among the listed hazardous wastes, they are of necessity extremely toxic, since their primary function is to kill dividing cells.  The organization may want to consider handling all chemotherapy agents with the same level of care that is required for the listed hazardous wastes.

Outline of the six steps

EPA recommends that you follow a six step process to determine whether a waste is hazardous. The steps are listed below, expressed as a series of questions:

The steps are discussed in some detail, with an emphasis on issues that would typically arise in healthcare facilities. Because the issues can get complicated, each section also provide links to more detailed information.

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