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Keep in mind that solid
waste does not have to
be a solid... it can also
include liquids, sludges,
and contained gases.

Abandoned means:

- disposed of,
- burned or incinerated,
- accumulated, stored,
or treated before or
in lieu of being
disposed of

Recycled means

- used in a manner
constituting disposal,
- burned for energy
- reclaimed, or
- accumulated



Hazardous waste comes in all shapes and forms. It may be solid, liquid or sludges. It may be the by-product of manufacturing processes or simply commercial chemical products, such as cleaning fluids or solvents, or battery acid that has been discarded. Whatever their form, however, proper management and disposal of hazardous waste is essential to protect our valuable natural resources.

According to the regulations, the first step of hazardous waste management requires the determination of whether or not waste materials you generate are hazardous waste. RCRA requires that a hazardous waste determination be performed on each waste stream a facility produces. This may include performing chemical analysis on the waste or perhaps simply using your knowledge of the waste to make that determination. Although hazardous waste determination can be a confusing process, it is vitally important to the proper management of hazardous waste. This module will take you through the hazardous waste determination process step-by-step.

In order to be a hazardous waste, a waste must first be a solid waste. There are certain wastes which are specifically excluded from the definition of a solid waste. Furthermore, certain solid wastes are specifically excluded from being a hazardous waste. If your waste appears on one of the hazardous waste lists, it is a listed hazardous waste. Additionally, there are specific standards to determine if the waste exhibits a hazardous characteristic, thus making it a characteristic hazardous waste. Our hazardous waste determination flowchart will help you follow the logic used in determining if a particular waste falls under the RCRA definition of a hazardous waste.

Solid Waste Definition

Under RCRA, the term solid waste is an important component of the regulations. The definition of solid waste is very broad and includes non-hazardous solid wastes, such as municipal garbage, but it also includes hazardous solid wastes.

A solid waste, as defined in 40 CFR 261.2, refers to any discarded material that is not excluded by definition or that is not excluded by a variance. According to the regulations a "discarded material" is any material which is:

  • abandoned,
  • recycled or accumulated, stored, or treated before recycling, or
  • considered inherently waste-like.

If your waste does not meet the definition of a solid waste, then it is not a hazardous waste.


If you can no longer use a material and you are planning to get rid of it, either by throwing it away or by burning it, that material would be classified as a solid waste. You are also not allowed to keep waste on site instead of disposing of it to bypass the regulations.

Recycled or Accumulated

Some wastes may still be solid wastes even if they are recycled. Anything recycled that is placed on the land or in the land ("used in a manner constituting disposal"), or anything that needs treatment, such as reclamation, before reuse is still classified as a solid waste. However, some materials may qualify for an exemption from the definition of solid waste and fall out of RCRA regulation when recycled.

Inherently Waste-like

EPA has specifically designated some materials as solid wastes through the inherently waste like definition. These materials, even when they are recycled, are considered solid wastes. They include dioxin containing materials like listed hazardous waste numbers F020, F021, F022, F023, F026 and F028 and other materials the EPA administrator deems hazardous.

Solid Waste Exclusions

If your waste meets the above definition of a solid waste, it still may not be regulated by EPA as solid waste. EPA has specifically excluded some materials from regulation under RCRA. If your waste is excluded from solid waste regulations then it is not a hazardous waste. Materials recycled in the following manner are not regulated:

  • used in an industrial process to make a product (without reclamation)
  • used as an effective substitute for another commercial chemical product
  • returned to the original process from which they are generated (without first being reclaimed)

Other wastes listed in 40 CFR Part 261.4(a) are also excluded.

  1. domestic sewage;
  2. industrial waste water discharges from point sources which are subject to regulation under the Clean Water Act
  3. irrigation return flows;
  4. nuclear materials regulated under the Atomic Energy Act of 1954;
  5. materials subject to in-situ mining techniques which are not removed from the ground as part of the extraction process;
  6. pulping liquors that are reclaimed in a pulping liquor recovery furnace and reused in the pulping process;
  7. spent sulfuric acid used to produce virgin sulfuric acid, unless it is accumulated speculatively.
  8. secondary materials that are reclaimed and returned to the original process provided that certain provisions found in 40 CFR 261.4(a)(8) are met
  9. spent wood preserving solutions that are reclaimed and reused for their original purpose; and,
  10. certain EPA listed K-wastes as described in 40 CFR 261.4(a)(10)
  11. Non-wastewater splash condenser dross residue from the treatment of K061 in high temperature metals recovery units provided it is shipped in drums and not land disposed before recovery
  12. certain oil bearing hazardous waste generated at a petroleum refinery as described in 40 CFR 261.4(a)(12)
  13. Excluded scrap metal being recycled
  14. Shredded circuit boards being recycled provided they meet the provisions listed in 40 CFR 261.4(a)(14) and
  15. other wastes as listed in 261.4(a).

If a material has been classified as a solid waste and does not meet any exclusions or exemptions, the next step in the hazardous waste identification process is to determine if the solid waste meets the definition of a hazardous waste.

Hazardous Waste Definition

The hazardous waste regulations specify that a material that is a "solid waste" is hazardous if it is not excluded from the regulations, and meets any of the following conditions:

  • Exhibits any of the characteristics of a hazardous waste;
  • Has been named as a hazardous waste and listed as such in the regulations;
  • Is a mixture containing listed hazardous waste and non-hazardous waste;
  • Is a waste derived from the treatment, storage or disposal of listed hazardous waste.

Hazardous Waste Definition and Exclusions

EPA spent many months interacting with industry and the public to develop a definition of "hazardous waste". EPA developed two primary types of hazardous waste. These wastes are commonly referred to as listed wastes and characteristic wastes. There are 4 hazardous waste lists and 4 hazardous waste characteristics which will be discussed in more detail below.

Listed Hazardous Waste Definition

EPA specifically determined that some wastes are hazardous by virtue of the manufacturing process from which they come. These wastes are incorporated into lists published by EPA. A hazardous waste listing is a narrative description of a specific type of waste that EPA considers dangerous enough to deserve regulation.

EPA has studied and listed hundreds of specific industrial wastestreams. These listed hazardous wastes are organized into three different categories which are found in the regulations at Part 261, Subpart D. These three categories include:

  • Non-Specific Source waste (the F - List) These are generic wastes commonly produced by manufacturing and industrial processes. Examples include spent halogenated solvents used in degreasing and wastewater treament sludges from electroplating processes as well as dioxins wastes. The F - List is codified in the regulations at 40 CFR 261.31.
  • Specific Source waste (the K - List) consists of wastes from specifically identified industries such as wood preserving, petroleum refining, and organic chemical manufacturing. These wastes typically include sludges, still bottoms, wastewaters, and residues. The K - List is found at 40 CFR 261.32.
  • Commercial chemical products (the P & U Lists) consists of specific commercial chemical products or manufacturing chemical intermediates. These lists include chemicals such as chlorform and creosote, acids such as sulfuric acid and hydrochloric acid, and pesticides such as DDT. The P list is comprised of acutely hazardous wastes. Both the P - List and U - List are codified in 40 CFR 261.33.

Each waste on the lists is assigned a hazardous waste code consisting of the letter associated with the list followed by three numbers. For example, the wastes listed as hazardous on the F - List are assigned the waste codes F001, F002, and so on.

F - List Wastes

The F - List wastes can be divided into several groups, depending on the type of manufacturing or industrial operation which creates them. The categories of F - Listed wastes are:

  • spent solvent wastes (F001 - F005),
  • wastes from electroplating and other metal finishing operations (F006 - F012, F019),
  • dioxin-bearing wastes (F020 - F023 and F026 - F028),
  • wastes from the production of certain chlorinated aliphatic hydrocarbons (F024, F025),
  • wastes from wood preserving (F032, F034, and F035),
  • petroleum refinery wastewater treatment sludges (F037 and F038), and
  • multisource leachate (F039).

The F001 through F005 wastes are generated by a large number of individuals, therefore we will highlight those wastes in this section. Individuals should reference 40 CFR 261.31 for an entire listing of F - List wastes.

F001 wastes include:

"...the following spent halogenated solvents when used in degreasing operations: tetrachloethylene, trichloroethylene, methylene chloride, 1,1,1-trichloroethane, carbon tetrachloride, and chlorinated fluorocarbons. These spent solvents must contain, before use, a total of 10% or more by volume of any of the solvents listed in F001, F002, F004 or F005...."

The key points to remember about F001 wastes are that the material must:

  1. be a spent halogenated solvent,
  2. be used in degreasing, and
  3. contain before use at least 10% of the listed solvents.

The F002 list contains nearly the same list of halogenated solvents in F001 however, the requirement for use in degreasing operations does not appear. The 10 % before use criteria is also present in the F002 list.

F003 wastes are non-halogenated solvents including xylene, acetone, ethyl acetate, ethyl benzene, ethyl ether, methyl isobutyl ketone, n-butyl alcohol, cyclohexanone and methanol with 10 % before use of solvents listed in F001, F002, F003, F004 and F005.

F004 wastes the are non halogenated solvents cresol, cresylic acid and nitrobenzene or mixtures containing at least 10 % before use of the solvents listed in F004, F001, F002, or F005.

F005 are also non-halogenated solvents including toluene, methyl ethyl ketone, carbon disulfide, isobutanol, pyridine, benzene, 2-ethoxyethanol and 2-nitropropane and spent solvent mixtures containing before use 10 % or more before use of the solvents listed in F001, F002, F004 and F005.

K - List Wastes

The K - List of hazardous wastes designates as hazardous, particular wastes from specific sectors of industry and manufacturing. Like F - List wastes, K -List wastes are manufacturing process wastes. When determining whether a waste qualifies as K - Listed, one should ask two primary questions.

  1. Is the facility that created the waste within one of the seventeen different industrial or manufacturing categories on the K - List?
  2. Does the waste match one of the specific K - List waste descriptions?

The seventeen industries that can generate K - List wastes are:

  1. wood preservation,
  2. inorganic pigment manufacturing,
  3. organic chemicals manufacturing,
  4. inorganic chemicals manufacturing,
  5. pesticides manufacturing,
  6. explosives manufacturing,
  7. petroleum refining,
  8. iron and steel production,
  9. primary copper production,
  10. primary lead production,
  11. primary zinc production,
  12. primary aluminum production,
  13. ferroalloys production,
  14. secondary lead processing,
  15. veterinary pharmaceuticals manufacturing,
  16. ink formulation, and
  17. coking (processing of coal to produce coke, a material used in iron and steel production).

Remember that not all wastes from these seventeen industries are hazardous, only those specifically described in the detailed K - List descriptions in 40 CFR 261.32.

P - and U - List Wastes

The P - and U - Lists designate as hazardous, pure or commercial grade formulations of certain unused chemicals. As you will see, the P - and U - Listings are quite different from the F - and K - Listings. For a waste to qualify as P - or U - Listed, a material must meet the following three criteria:

  1. The chemical must appear on the P - or U - List
  2. The chemical must be unused
  3. The chemical must be in the form of a "commercial chemical product,"

The P - and U - Lists do not apply to manufacturing process wastes, as do the F - and K - Lists. The P - and U - Listings apply to unused chemicals, spill residues, off-specification species, or container residues that become wastes. P Wastes are considered acutely hazardous wastes. Generation of over 1 kilogram of acutely hazardous waste will cause classification as a Large Quantity Generator. (Generator Status will be discussed further in Module III) Unused chemicals become wastes for a number of reasons. For example, some unused chemicals are spilled by accident. Others are intentionally discarded because they are off-specification and cannot serve the purpose for which they were originally produced. See 40 CFR 261.33.

Characteristic Hazardous Waste Definition

The definitions of characteristic wastes are found in 40 CFR 261 Subpart C. The four hazardous waste characteristics are:

  1. Ignitability
  2. Corrosivity
  3. Reactivity
  4. Toxicity

Ignitable, corrosive, and reactive wastes carry the waste codes D001, D002, and D003, respectively. Wastes displaying the characteristic of toxicity can carry any of the waste codes D004 through D043.

Ignitability D001 includes materials that:

  • any liquid with a flashpoint less than 140 F,
  • non-liquids capable of producing fire due to friction or moisture,
  • ignitable compressed gases, and
  • oxidizers listed by DOT.

Ignitable wastes can create fires under certain conditions. Examples include paint, and certain degreasers and solvents.

Corrosivity D002 includes any material:

  • that has a pH less than or equal to 2 or greater than or equal to 12.5, and
  • able to corrode steel at a rate greater than 0.25 inches per year.

Corrosive wastes are acidic or alkaline (basic) wastes which can readily corrode or dissolve metal, or other materials. They are also among the most common hazardous wastestreams. Waste sulfuric acid from automotive batteries is an example of a corrosive waste.

Reactivity D003 includes materials that:

  • are normally unstable and readily undergo violent change without detonation,
  • reacts violently with water,
  • forms potentially explosive mixtures with water,
  • generates toxic gases when mixed with water, and
  • are forbidden explosives according to the Department of Transportation .

A reactive waste is one that is unstable and explodes or produces toxic fumes, gases andvapors when mixed with water or unders other conditions such as heat and pressure. Common examples are certain cyanides or sulfide bearing wastes.

Toxicity Characteristics

The leaching of toxic compounds from landfill wastes is one of the most common sources of groundwater contamination. In response to this issue, EPA regulated hazardous wastes likely to leach toxic chemicals into groundwater. EPA first designed a lab procedure which replicates the leaching process and other effects that occur when wastes are buried in a typical landfill. This lab procedure is known as the Toxicity Characteristic Leaching Procedure (TCLP). If the procedures indicates any of 39 different toxic chemicals above specified regulatory levels then the wastes exhibits the toxicity characteristic (TC).

The concentration levels for D004-D043 wastes are listed in Table 2-1. These wastes include pesticides, metal bearing wastes, and organic compound wastes

Hazardous Waste Exclusions

EPA has excluded several wastes from regulation as hazardous waste. The exclusions are found in 40 CFR Part 261.4(b) . The exclusions primarily apply to wastes already regulated by other Federal regulations, or for materials to difficult to regulate by EPA. The exclusions include:

  1. household hazardous waste;
  2. wastes associated with growing agricultural crops or raising animals, which are returned to the soil as fertilizers;
  3. mining overburden returned to the mine site;
  4. fly ash, bottom ash, slag and flue gas emission control waste generated primarily from the combustion of coal and other fossil fuels;
  5. wastes associated with the exploration, development, or production of crude oil, natural gas or geothermal energy;
  6. trivalent chromium generated through an industrial process and managed in a non-oxidizing environment;
  7. specific wastes from the leather tanning and finishing industry;
  8. certain wastes from the extraction and processing or ores and minerals;
  9. cement kiln dust waste;
  10. discarded arsenic treated wood;
  11. petroleum contaminated media subject to clean-up under part 280 of RCRA;
  12. injected groundwater that is hazardous only because it exhibits a characteristic (D018-D043) that is reinjected
  13. Used chloroflurocarbon refrigerants from totally enclosed heat transfer equipment and,
  14. non-terne platedused oil filters provided that the used oil has been removed.

If a material meets one of the exclusions from the definition of hazardous waste, then it is not a hazardous waste.

Mixture and Derived from Rule

Orginally when EPA developed the RCRA program, they focused on establishing the listings and characteristics, criteria allowing industry to identify which wastes deserved regulation as hazardous wastes. Commenters to EPA's original proposed regulations brought up other key questions about the hazardous waste identification process. For example, these commenters asked, "once a waste is identified as hazardous, what happens if that waste changes in some way? If the hazardous waste is changed, either by mixing it with other wastes or by treating it to modify its chemical composition, should it still be regulated as hazardous?" Faced with a short time frame for answering these difficult questions, EPA developed a fairly simple and strict answer: the mixture and derived-from rules.

The mixture rule basically states that if a listed hazardous waste is mixed with a solid waste, then the resulting mixture is a hazardous waste. This mixture rule is intended to prevent the dilution of hazardous waste to circumvent the regulations. In addition, mixtures of characteristic hazardous wastes and solid wastes are considered hazardous if the mixture still exhibits a characteristic.

Listed hazardous waste + any solid waste = Hazardous Waste

Characteristic waste + solid waste = Determine if waste still meets characteristic

The derived-from rule governs the regulatory status of materials that are created by treating or changing a hazardous waste in some way. For example, ash created by burning a hazardous waste is considered "derived-from" that hazardous waste. The derived-from rule for listed wastes states that any material derived from a listed hazardous waste is also a listed hazardous waste. Solid wastes generated during the treatment, storage, or disposal of hazardous waste are considered hazardous wastes. This includes sludges, spill residues, ash, emission control dust and leachate. This derived from rule was implemented to prevent the incomplete treatment of hazardous waste. Currently, a listed waste is still considered hazardous waste even after treatment and must be disposed of in a properly permitted RCRA landfill.

Generators are required to determine if they generate any hazardous wastes. They may perform analytical testing to identify their waste, or use their knoweldge of the waste's chemical and physical properties to determine if the material is hazardous. Generators also must determine their generator status by calculating the amount of hazardous wastes the produce each month. The next chapter will discuss Generator Status

Used Oil, Universal Waste and Mercury Containing Lights

Used oil and universal wastes have been treated separately from most other wastes. Used oil is subject to the standards found in Part 279 when recycled. Universal wastes such as batteries, pesticides, mercury-containing thermostats and mercury containing lights are subject to the Universal waste standards of Part 273.

EPA introduced a new used oil management program in 1992. Under the new program, used oil recycled in any manner would be subject to Part 279. The used oil management requirements are
discussed in detail in Module VII.

In 1995, EPA created a new set of regulations for the collection of certain hazardous wastes.
The "Universal Waste Rule," in Part 273 will be discussed in Module VII as well.


At the beginning of this module, you learned to determine if your waste stream qualifies as a solid waste. All solid waste generators must determine if their waste is hazardous and therefore subject to the hazardous waste regulations. A hazardous waste meets one of four conditions developed by EPA.

At this point, you should be able to determine if your facility generates hazardous waste.

Something to Think About

"Garbage, refuse, or sludge or any other waste material...because of its quantity, concentration or physical, chemical, or infectious characteristics, may cause, or significantly contribute to, an increase in mortality or an increase in serious irreversible or incapacitating reversible illness; or pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, or disposed of, or otherwise managed."
- Congressional definition of hazardous waste found in the RCRA law.

The RCRA law provides a general definition of the term "hazardous waste." However, in order to regulate hazardous wastes, EPA first had to determine which specific wastes are hazardous. Since their are tens of thousands of wastes that could be hazardous for many different reasons, this was not an easy task. The selection of the definition of hazardous waste would have enormous ramifications. Only wastes determined to be hazardous would be subject to RCRA's hazardous waste regulations.


Module IModule IIModule IIIModule IVModule VModule VIModule VIIModuleVIII

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