Solid Waste and Emergency Response
                                       (5305W)
                                   EPA530-K-05-012
                     Introduction to
                Hazardous Waste
                   Identification
                  (40 CFR Parts 261)
United States
Environmental Protection
Agency
September 2005

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                   HAZARDOUS WASTE IDENTIFICATION
                                      CONTENTS
1.  Introduction   	  1

2.  Regulatory Overview	  2
   2.1  Hazardous Waste Identification Process	  2
   2.2  Definition of Hazardous Waste	  3
   2.3  Listed Hazardous Wastes	  5
   2.4  Characteristic Hazardous Wastes	13
   2.5  Wastes Listed Solely For Exhibiting the Characteristics of Ignitability,
        Corrosivity, and/or Reactivity	17
   2.6  The Mixture and Derived-from Rules	17
   2.7  The Contained-in Policy 	21

3.  Regulatory Developments	24
   3.1  The Hazardous Waste Identification Rules	24
   3.2  Final Hazardous Waste Listing Determinations	25
   3.3  Proposed Revision of Wastewater Treatment Exemption for Hazardous
        Waste Mixtures	25

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                                                                 Hazardous Waste Identification -1
                                1.  INTRODUCTION


"Is my waste a hazardous waste regulated under the Resource Conservation and Recovery Act
(RCRA)?" This is one of the most common and basic RCRA questions and is the key to the
RCRA hazardous waste program. If something is not a hazardous waste, it is not regulated under
RCRA. Proper identification of a hazardous waste can be a difficult and confusing task, as the
RCRA regulations establish a complex definition of the term "hazardous waste." To help make
sense of what is and is not a hazardous waste, this module presents the steps involved in the
process of identifying, or "characterizing," a hazardous waste.

While introducing the entire hazardous waste identification process, this module will focus on
the final steps, the definition of a hazardous waste.  The other steps in the process, including the
definition of solid waste and the solid and hazardous waste exclusions will be discussed in other
modules.

After reading this module, you will be able to explain the hazardous waste identification process
and the definition of hazardous waste, and be familiar with the following concepts:

      hazardous waste listings

      hazardous waste characteristics

      the "mixture" and "derived-from" rules

      the "contained-in" policy

      the Hazardous Waste Identification Rules (HWIR).
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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2 - Hazardous Waste Identification
                        2.   REGULATORY OVERVIEW
What is a hazardous waste?  In its most basic form, the answer to that question can be quite
simple. A hazardous waste is a waste with a chemical composition or other properties that make
it capable of causing illness, death, or some other harm to humans and other life forms when
mismanaged or released into the environment. Developing a regulatory program that ensures the
safe handling of such dangerous wastes, however, demands a far more precise definition of the
term.  EPA therefore created hazardous waste identification regulations that outline a process to
determine whether any particular material is a hazardous waste for the purposes of RCRA.
2.1    HAZARDOUS WASTE IDENTIFICATION PROCESS

Proper hazardous waste identification is essential to the success of the hazardous waste
management program. The RCRA regulations at 40 CFR 262.11 require that any person who
produces or generates a waste must determine if that waste is hazardous.  In doing so, 262.11
presents the steps in the hazardous waste identification process:

      Is the waste a "solid waste"?
      Is the waste specifically excluded from the RCRA regulations?
      Is the waste a "listed" hazardous waste?
      Does the waste exhibit a characteristic of hazardous waste?

When faced with the question of whether or not a waste is regulated as hazardous under RCRA,
turn to 262.11. This regulation will remind you of the four steps in the RCRA hazardous waste
identification process.

IS THE WASTE A SOLID WASTE?

Hazardous waste identification begins with an obvious point: in order for any material to be a
hazardous waste, it must first be a waste. But, deciding whether an item is or is not a waste is not
always easy. For example, a material (like an aluminum can) that one person discards could seem
valuable to another person who recycles that material. EPA developed a set of regulations to assist
in determining whether a material is a waste. RCRA uses the term "solid waste" in place of the
common term "waste."  Under RCRA, the term "solid waste" means any waste, whether it is a
solid, semisolid, or liquid. The  first section of the RCRA hazardous waste identification
regulations focuses on the definition of solid waste.  For this module, you need only understand in
general terms the role that the definition of solid waste plays in the RCRA hazardous waste
identification process.  Another module, Definition of Solid Waste and Hazardous Waste
Recycling, explains the definition of solid waste in greater detail.

IS THE WASTE EXCLUDED?

Only a small fraction of all RCRA solid wastes actually qualify as hazardous wastes.  At first
glance, one would imagine that distinguishing between hazardous and nonhazardous wastes is a


      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                       But is an introduction to the topic used for training purposes.

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                                                                Hazardous Waste Identification - 3
simple matter of chemical and toxicological analysis. Other factors must be considered,
however, before evaluating the actual hazard that a waste's chemical composition poses.
Regulation of certain wastes may be impractical, unfair, or otherwise undesirable, regardless of
the hazards they pose. For instance, household waste can contain dangerous chemicals, like
solvents and pesticides, but making households subject to the strict RCRA waste management
regulations would create a number of practical problems.  Congress and EPA exempted or
excluded certain wastes, like household wastes, from the hazardous waste definition and
regulations. Determining whether or not a waste is excluded or exempted from hazardous waste
regulation is the second step in the RCRA hazardous waste identification process. Only after
determining that a solid waste is not somehow excluded from hazardous waste regulation should
the analysis proceed to evaluate the actual chemical hazard that a waste poses.  The module
entitled Solid and Hazardous Waste Exclusions explains which wastes are excluded from
hazardous waste regulation.

IS THE WASTE A LISTED HAZARDOUS WASTE, OR DOES IT EXHIBIT A
CHARACTERISTIC?

The final steps in the hazardous waste identification process determine whether a waste actually
poses a sufficient chemical or physical hazard to merit regulation.  These steps in the hazardous
waste identification process involve evaluating the waste in light of the regulatory definition of
hazardous waste.  The remainder of this module explains the definition of hazardous waste in
detail.
2.2    DEFINITION OF HAZARDOUS WASTE

A discussion of the definition of hazardous waste should begin with Congress' original statutory
definition of the term. RCRA 1004(5) defines hazardous waste as:

       A solid waste, or combination of solid waste, which because of its quantity,
       concentration, or physical, chemical, or infectious characteristics may (a) cause,
       or significantly contribute to, an increase in mortality or an increase in serious
       irreversible, or incapacitating reversible, illness; or (b) pose a substantial present
       or potential hazard to human health or the environment when improperly treated,
       stored, transported, or disposed of, or otherwise managed.

This broad statutory definition provides a general indication of which wastes Congress intended
to regulate as hazardous, but it obviously does not provide the clear distinctions necessary for
industrial waste handlers to determine whether their wastes pose a sufficient threat to warrant
regulation or not.  Congress instructed EPA to develop more specific criteria for defining
hazardous waste.  There are therefore two definitions of hazardous waste under the RCRA
program: a statutory definition and a regulatory definition. The statutory definition cited above
is seldom used today. It served primarily as a general guideline for EPA to follow in developing
the regulatory definition of hazardous waste.  The regulatory definition is an essential element of
the current RCRA program.  It precisely identifies which wastes are subject to RCRA waste
management regulations.
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                       But is an introduction to the topic used for training purposes.

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4 - Hazardous Waste Identification
Congress asked EPA to fulfill the task of developing a regulatory definition of hazardous waste
by using two different mechanisms: by listing certain specific wastes as hazardous and by
identifying characteristics which, when present in a waste, make it hazardous. Following its
statutory mandate, EPA developed a regulatory definition of hazardous waste that incorporates
both listings and characteristics.

HAZARDOUS WASTE LISTINGS

A hazardous waste listing is a narrative description of a specific type of waste that EPA
considers dangerous enough to warrant regulation. Hazardous waste listings describe wastes
from various industrial processes, wastes from specific sectors of industry, or wastes in the form
of specific chemical formulations.  Before developing a hazardous waste listing, EPA thoroughly
studies a particular wastestream and the threat it can pose to human health and the environment.
If the waste poses enough of a threat, EPA includes a precise description of that waste on one of
the hazardous waste lists  in the regulations.  Thereafter, any waste fitting that narrative listing
description is considered  hazardous, regardless of its chemical composition or any other potential
variable. For example, one of the current hazardous waste listings reads as: "API separator
sludge from the petroleum refining industry."  An API separator is a device commonly used by
the petroleum refining industry to separate contaminants from refinery wastewaters. After
studying the petroleum refining industry and typical sludges from API separators, EPA decided
these sludges were dangerous enough to  warrant regulation as hazardous waste under all
circumstances.  The listing therefore designates all petroleum refinery API separator sludges as
hazardous.  Chemical composition  or other factors about a specific sample of API separator
sludge are not relevant to its status  as hazardous waste under the RCRA program.

Using listings to define hazardous wastes presents  certain advantages and disadvantages. One
advantage is that listings  make the hazardous waste identification process easy for industrial
waste handlers. Only knowledge of a waste's origin is needed to determine if it is listed;
laboratory analysis is unnecessary.  By comparing any waste to narrative listing descriptions, one
can easily determine whether or not the waste is hazardous.  EPA's use of listings also presents
certain disadvantages.  For example, listing a waste as hazardous demands extensive study of
that waste by EPA.  EPA lacks the  resources to investigate the countless types of chemical
wastes produced in the United States  - the hazardous waste listings simply cannot address all
dangerous wastes.  Another disadvantage of the hazardous waste listings is their lack of
flexibility.  Listings designate a waste as hazardous if it falls within a particular category or class.
The actual composition of the waste is not a consideration as long as the waste matches the
appropriate listing description. For instance, some API  separator sludges from petroleum
refining might contain relatively few  hazardous constituents and pose a negligible risk to human
health and the environment.  Such sludges are still regulated as hazardous, however, because the
listing for this wastestream does not consider the potential variations in waste composition.
Thus, the hazardous waste listings can unnecessarily regulate some wastes that do not pose a
significant health threat.  It is also possible for industries to substantially change their processes
so that wastes would no longer meet a listing description in spite of the presence of hazardous
constituents. The hazardous waste characteristics provide an important complement to listings
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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                                                                  Hazardous Waste Identification - 5
by addressing most of the shortcomings of the listing methodology of hazardous waste
identification.

HAZARDOUS WASTE CHARACTERISTICS

A hazardous waste characteristic is a property which, when present in a waste, indicates that the
waste poses a sufficient threat to merit regulation as hazardous.  When defining hazardous waste
characteristics,  EPA does not study particular wastestreams from specific industries. Instead,
EPA asks the question, "what properties or qualities can a waste have which cause that waste to
be dangerous?" For example, EPA found that ignitability,  or the tendency for a waste to easily
catch fire and burn, is a dangerous property.  Thus, ignitability is one of the hazardous waste
characteristics and a waste displaying that property is regulated as hazardous, regardless  of
whether the waste is listed. When defining hazardous waste characteristics, EPA identifies,
where practicable, analytical tests capable of detecting or demonstrating the presence of the
characteristic. For instance, EPA regulations reference a laboratory flash point test to be used
when deciding if a liquid waste is ignitable.  Whether or not a waste displays a hazardous
characteristic generally depends on how it fares in one of the characteristics tests.  Therefore, the
chemical makeup or other factors about the composition of a particular waste typically determine
whether or not it tests as hazardous for a characteristic.

Using characteristics to define hazardous wastes presents certain advantages over designating
hazardous wastes by listings.  One advantage is that hazardous characteristics and the tests used
to evaluate their presence have broad applicability. Once EPA has defined a characteristic and
selected a test for use  in identifying it, waste handlers can evaluate any wastestream to see if it is
classified as a hazardous waste. Furthermore, use of characteristics can be a more equitable way
of designating wastes as hazardous. Instead  of categorizing an entire group of wastes as
hazardous, characteristics allow a waste handler to evaluate each waste sample on its own merits
and classify it according to the actual danger it poses. Aware of these advantages, EPA
originally planned to use characteristics as the primary means of identifying hazardous waste.
EPA hoped to define and select test methods for identifying all hazardous characteristics,
including organic toxicity, mutagenicity (the tendency to cause mutations), teratogenicity (the
tendency to cause defects in offspring), bioaccumulation potential, and phytotoxicity (toxicity to
plants). EPA encountered problems, however, when trying to develop regulatory definitions of
these properties. One primary problem was that no straightforward testing protocols were
available for use in determining if a waste possessed any of these characteristics.  For example,
deciding if a particular wastestream poses  an unacceptable cancer risk demands extensive
laboratory experimentation.  Requiring such analysis on a routine basis from industrial waste
handlers would be impractical.  Therefore, EPA developed a hazardous waste definition that
relies on both listings and characteristics to define hazardous wastes.
2.3    LISTED HAZARDOUS WASTES

EPA has studied and listed as hazardous hundreds of specific industrial wastestreams.  These
wastes are described or listed on four different lists that are found in the regulations at Part 261,
Subpart D. These four lists are:
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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6 - Hazardous Waste Identification
       The F list  The F list designates particular solid wastes from certain common
       industrial or manufacturing processes as hazardous.  Because the processes
       producing these wastes can occur in different sectors of industry, the F list wastes
       are known as wastes from nonspecific sources. The F list is codified in the
       regulations at 261.31.

       The K list  The K list designates particular solid wastes from certain specific
       industries as hazardous. K list wastes are known as wastes from specific sources.
       The K list is found at 261.32.

       The P list and the U list  These two lists are similar in that both list pure or
       commercial grade formulations of certain specific unused chemicals as hazardous.
       Both the P list and U list are codified in 261.33.

These four lists each designate anywhere from 30 to a few hundred wastestreams as hazardous.
Each waste on the lists is assigned a waste code consisting of the letter associated with the list
followed by three numbers. For example, the wastes on the F list are assigned the waste codes
F001, F002, and so on.  These waste codes are an important part of the RCRA regulatory system.
Assigning the correct waste code to a waste has important implications for the management
standards that apply to the waste.

LISTING CRITERIA

Before listing any waste as hazardous, the Agency developed a set of criteria to use as a guide
when determining whether or not a waste should be listed.  These listing criteria provide a
consistent frame of reference when EPA considers listing a wastestream. Remember that EPA
only uses these criteria when evaluating whether to list a waste; the listing criteria are not used
by waste handlers, who refer to the actual hazardous waste lists for hazardous waste
identification purposes. There are four different criteria upon which EPA may base its
determination to list a waste as hazardous.  These criteria are codified in Part 261, Subpart B.
Note that these four criteria do not directly correspond to the four different lists of hazardous
waste.  The four criteria EPA may use to list a waste are:

       The waste typically contains harmful chemicals, and other factors indicate that it
       could pose a threat to human health and the environment in the absence of special
       regulation.  Such wastes are known as toxic listed wastes.

       The waste contains such dangerous chemicals that it could pose a threat to human
       health and the  environment even when properly managed.  Such wastes are
       known as acutely hazardous wastes.

       The waste typically exhibits one of the four characteristics of hazardous waste
       described in the hazardous waste identification regulations (ignitability,
       corrosivity, reactivity, or toxicity).
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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                                                                 Hazardous Waste Identification - 7
       When EPA has to cause to believe for some other reason, the waste typically fits
       within the statutory definition of hazardous waste developed by Congress.

EPA may list a waste as hazardous for any and all of the above reasons. The majority of listed
wastes fall into the toxic waste category. To decide if a waste should be a toxic listed waste,
EPA first determines whether it typically contains harmful chemical constituents. Appendix VIII
of Part 261 contains a list of chemical compounds or elements which scientific studies show to
have toxic, carcinogenic, mutagenic, or teratogenic effects on humans or other life forms. If a
waste contains chemical constituents found on the Appendix VIII list, EPA then evaluates 11
other factors to determine if the wastestream is likely to pose a threat in the absence of special
restrictions on its handling. These additional considerations include a risk assessment and study
of past cases of damage  caused by the waste.

Acutely hazardous wastes are the second most common type of listed waste.  EPA designates a
waste as acutely  hazardous if it contains Appendix VIII constituents that scientific studies show
to be fatal to humans or  animals in low doses. In a few cases,  acutely  hazardous wastes contain
no Appendix VIII constituents, but are extremely dangerous for another reason. An example is
the listed waste P081, which designates unused discarded formulations of nitroglycerine as
acutely hazardous. Although nitroglycerine is not an Appendix VIII hazardous  constituent,
wastes containing unused nitroglycerine are so unstable that they pose an acute hazard.  The
criteria for designating a waste as acutely hazardous require only that EPA considers the typical
chemical makeup of the wastestream. EPA is not required to study other factors, such as relative
risk and evidence of harm, when listing a waste as acutely hazardous.

To indicate its reason for listing a waste, EPA assigns a hazard code to each waste listed on  the
F, K, P, and U lists. These hazard codes are listed below.  The last four hazard codes apply  to
wastes that have been listed because they typically exhibit one of the four regulatory
characteristics of hazardous waste. You will learn more about the four characteristics of
hazardous waste. The hazard codes indicating the basis for listing a waste are:
Toxic Waste
Acute Hazardous Waste
Ignitable Waste
Corrosive Waste
Reactive Waste
Toxicity Characteristic Waste
(T)
(H)
(I)
(C)
(R)
(E)
The hazard codes assigned to listed wastes affect the regulations that apply to handling the waste.
For instance, acute hazardous wastes accompanied by the hazard code (H) are subject to stricter
management standards than most other wastes.

THE F LIST: WASTES FROM NONSPECIFIC SOURCES

The F list designates as hazardous particular wastestreams from certain common industrial or
manufacturing processes. F list wastes usually consist of chemicals that have been used for their
intended purpose in an industrial process. That is why F list wastes are known as
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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8 - Hazardous Waste Identification
"manufacturing process wastes." The F list wastes can be divided into seven groups, depending
on the type of manufacturing or industrial operation that creates them. The seven 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)
       multi source  leachate  (F039).

Spent Solvent Wastes

Waste codes F001 - F005 apply to wastestreams from the use of certain common organic
solvents. Solvents are chemicals with many uses, although they are most often used in
degreasing or cleaning. The solvents covered by the F listings are commonly used in industries
ranging from mechanical repair to dry cleaning to electronics manufacturing. EPA decided that
only certain solvents used in certain ways produce wastestreams that warrant a hazardous waste
listing.  Therefore, a number of key factors must be evaluated in order to determine whether the
F001 - F005 waste codes apply to a particular waste solvent. First, one or more of the 31
specific organic solvents designated in the F001 - F005 listing description must have been used
in the operation that created the waste. Second, the listed solvent must have been used in a
particular manner - it must have been used for its "solvent properties," as EPA defines that
expression.  Finally, EPA decided that only a wastestream created through use of concentrated
solvents should be listed. Thus, the  concentration of the solvent formulation or product before
its use in the process that created the waste is also a factor in determining the applicability of the
F001 - F005 listing.

The F001 - F005 spent solvent listings provide a good illustration of a principle common to all
listed hazardous wastes. To  determine whether a waste qualifies as listed, knowledge of the
process that created the waste is essential, while information about the waste's chemical
composition is often irrelevant. For example, the F005 listing description can allow two
different wastes with identical chemical contents to be regulated differently because of subtle
differences in the processes that created the wastes. A waste made up of toluene  and paint is
F005 if the toluene has been  used to clean the paint from brushes or some other surface.  A waste
with the same chemical composition is not F005 if the toluene has been used as an ingredient
(such as a thinner) in the paint.  EPA considers use as a cleaner to be "use as a solvent;" use as an
ingredient does not  qualify as solvent use.  As you can see, knowledge of the process that created
a waste  is the key in evaluating whether a waste can be a hazardous  spent solvent or other listed
hazardous waste.
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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                                                                 Hazardous Waste Identification - 9
Wastes from Electroplating and Other Metal-Finishing Operations

The listed hazardous wastes F006 - F012 and F019 are wastes commonly produced during
electroplating and other metal finishing operations. Diverse industries use electroplating and
other methods to change the surface of metal objects in order to enhance the appearance of the
objects, make them more resistant to corrosion, or impart some other desirable property to them.
Industries involved in plating and metal finishing range from jewelry manufacture to automobile
production.  A variety of techniques can be used to amend a metal's surface. For example,
electroplating uses electricity to deposit a layer of a decorative or protective metal on the surface
of another metal object. Chemical conversion coating also amends the surface of a metal, but
does so by chemically converting (without use of electricity) a layer of the original base metal
into a protective coating.  Because each of these processes produces different types of wastes,
EPA only designated wastes from certain metal-finishing operations as hazardous.  The first step
in determining whether one of the F006-F012 or F019 listings applies to a waste is identifying
the  type of metal finishing process involved in creating the waste:

       F006 - F009 listings only apply to wastes from electroplating operations
       F010 - F012 listings only apply to wastes from metal heat treating operations
       the F019 listing only applies to wastes from the chemical conversion coating of
       aluminum.

Dioxin-Bearing Wastes

The listed wastes F020 - F023 and F026 - F028 are commonly known as the "dioxin-bearing
wastes." These listings describe a number of wastestreams that EPA believes are likely to
contain dioxins, which are considered to be among the most dangerous known chemical
compounds. The dioxin listings apply primarily to manufacturing process wastes from the
production of specific pesticides or specific chemicals used in the production of pesticides. The
F027 listing deserves special notice because it does not apply to used manufacturing wastes.  It
applies only to certain unused pesticide formulations. F027 is in fact the only listing on the F list
or K list that describes an unused chemical rather than an industrial wastestream consisting of
chemicals that have served their intended purpose. With the exception of F028, all of the dioxin-
bearing wastes are considered acute hazardous wastes and are designated with the hazard code
(H). These wastes are therefore subject to stricter management standards than other hazardous
wastes.

Wastes from the Production of Certain Chlorinated Aliphatic Hydrocarbons

The F024 and F025 listings designate as hazardous certain wastestreams produced in the
manufacture of chlorinated aliphatic hydrocarbons. These listings stand out on the F list (the list
of wastes from nonspecific sources) because they focus on wastes from a very narrow industrial
sector. Many other wastestreams from the manufacture of organic chemicals are listed on the K
list, the list of wastes from specific sources, including two waste codes for chlorinated  aliphatic
wastes, K174 and K175.
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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10 - Hazardous Waste Identification
Wood Preserving Wastes

The F032, F034, and F035 listings apply to certain wastes from wood preserving operations.
Many types of wood used for construction or other non-fuel applications is chemically treated to
slow the deterioration caused by decay and insects.  Such chemical treatment is commonly used
in telephone poles, railroad ties, and other wood products prepared to withstand the rigors of
outdoor use. Wood preservation typically involves pressure treating the lumber with
pentachlorophenol, creosote, or preservatives containing arsenic or chromium. (It should be
noted that after December 31, 2003, many wood treaters will not be using arsenic or chromium
based inorganic preservatives.) The wood preserving process creates a number of common
wastestreams containing these chemicals. For example, once wood has been treated with a
preservative excess preservative drips from the lumber. The F032, F034, and F035 listings
designate this preservative drippage as listed hazardous waste.  These listings also apply to a
variety of other residues from wood preserving. Whether the F032, F034, or F035 listings apply
to a particular wood preserving waste depends entirely on the type of preservative used at the
facility. Waste generated from wood preserving processes using pentachlorophenol is F032,
waste from the use of creosote is F034, and waste from treating wood with arsenic or  chromium
is F035. The K list also includes a waste code, K001, which applies to bottom sediment sludge
from treating wastewaters associated with processes using pentachlorophenol and/or creosote.

Petroleum Refinery Wastewater Treatment Sludges

The F037  and F038 listings apply to specific wastestreams from petroleum refineries.  The
petroleum refining process typically creates large quantities of contaminated wastewater. Before
this wastewater can be discharged to a river or sewer, it must be treated to remove oil, solid
material, and chemical pollutants.  Gravity provides a simple way of separating these pollutants
from refinery wastewaters.  Over time, solids and heavier pollutants precipitate from wastewaters
to form a sludge.  Other less dense pollutants accumulate on the surface of wastewaters, forming
a material known as float.  These gravitational separation processes can be encouraged through
chemical or mechanical means.  The F037 listing  applies to the sludges and float created by
gravitational treatment of petroleum refinery wastewaters. The F038 listing applies to sludges
and float created during the chemical or physical treatment of refinery  wastewaters. The K list
also includes waste codes for certain petroleum wastestreams generated by the petroleum
refining industry. These waste codes are K048 through K052 and K169 through K172.

Multisource Leachate

The F039  listing applies to multisource leachate, the liquid material that accumulates at the
bottom of a hazardous waste landfill. Understanding the natural phenomenon known  as leaching
is essential to understanding a number of key RCRA regulations.  Leaching occurs when liquids
such as rainwater filter through soil or buried materials, such as wastes placed in a landfill.
When this liquid comes in contact with buried wastes, it leaches or draws chemicals out of those
wastes.  This liquid (called leachate) can then carry the leached chemical contaminants further
into the ground, eventually depositing them  elsewhere in the subsurface or in groundwater. The
leachate that percolates through landfills, particularly hazardous waste landfills, usually  contains
high concentrations of chemicals, and is often collected to minimize the potential that it  may
enter the subsurface environment and contaminate soil or groundwater. This leachate that

      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                       But is an introduction to the topic used for training purposes.

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                                                                Hazardous Waste Identification - 11
percolates through hazardous waste landfills and other buried hazardous waste is designated as
F039.

THE K LIST: WASTES FROM SPECIFIC SOURCES

The K list of hazardous wastes designates particular wastes from specific sectors of industry and
manufacturing as hazardous. The K list wastes are therefore known as wastes from specific
sources.  Like F list wastes, K list wastes are manufacturing process wastes. They contain
chemicals that have been used for their intended purpose.  To determine whether a waste
qualifies as K-listed, two primary questions must be answered. First, is the facility that created
the waste within one of the industrial or manufacturing categories on the K list?  Second, does
the waste match one of the specific K list waste descriptions? The 13 industries that can
generate K list wastes are:

      wood preservation
      inorganic pigment manufacturing
       organic chemicals manufacturing
      inorganic chemicals manufacturing
      pesticides manufacturing
      explosives manufacturing
      petroleum refining
      iron and steel production
      primary aluminum production
      secondary lead processing
      veterinary pharmaceuticals manufacturing
      ink formulation
      coking (processing of coal to produce coke, a material used in iron and steel
       production).

Remember that not all wastes from these 13 industries are hazardous, only those specifically
described in the detailed K list descriptions.

Previously, the K list included waste codes for 17 different industries.  However, EPA revoked
the K waste codes applicable to the wastestreams in the primary copper, primary lead, primary
zinc, and ferroalloys industries (K064, K065, K066, K090, and K091) (63 FR 28556, 28579;
May 26,  1998). Currently, there are no K waste codes applicable to these four industries.

In general, the K listings target much more specific wastestreams than the F listings. For
example, EPA added a number of listings to the petroleum refining category of the K list.  EPA
estimates that one hundred facilities nationwide produce wastestreams covered by these new K
listings.  In contrast, F-listed spent solvent wastes are commonly generated in thousands of
different plants and facilities. You may also notice that industries generating K-listed wastes,
such as the wood preserving and petroleum refining industries, can also generate F-listed wastes.
Typically, K listings describe more specific wastestreams than F listings applicable to the same
industry. For example, K051 and K048 designate as hazardous two very specific types of
petroleum refinery wastewater treatment residues: wastewater treatment sludges created in API
separators and wastewater treatment float created using dissolved air flotation (DAF) pollution

     The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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12 - Hazardous Waste Identification
control devices.  The F037 and F038 listings complement these two K listings by designating as
hazardous all other types of petroleum refinery wastewater treatment sludges and floats. These
petroleum refinery listings illustrate that the K listings are typically more specific than the F
listings. They also illustrate that the two lists are in many ways very similar.

THE P AND U LISTS: DISCARDED COMMERCIAL CHEMICAL PRODUCTS

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 waste must meet the following three criteria:

       the waste must contain one  of the chemicals listed on the P or U list
       the chemical in the waste must be unused
       the chemical in the waste must be in the form of a "commercial chemical product," as
       EPA defines that term.

The following paragraphs explore these three criteria in detail and examine EPA's rationale in
creating the P and U lists.

You have already learned that hazardous waste listings are narrative descriptions of specific
wastestreams and that a waste's actual chemical composition is generally irrelevant to whether a
listing applies to it.  At first glance, the P and U listings seem inconsistent with these principles.
Each P and U listing consists only of the chemical name of a compound known to be toxic or
otherwise dangerous; no description is included.  EPA adopted this format because the same
narrative description applies to all P and U list wastes. Instead of appearing next to each one of
the hundreds of P and U list waste codes, this description is found in the regulatory text that
introduces the two lists.

The generic P and U list waste description involves two key factors.  First, a P or U listing
applies only if one of the listed chemicals is discarded unused. In other words, 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 that become wastes.  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.

The second key factor governing the applicability of the P or U listings is that the listed chemical
must be discarded in the form of a "commercial chemical product." EPA uses the phrase
commercial  chemical product to describe a chemical that is in pure form, that is in commercial
grade form, or that is the  sole active ingredient in a chemical formulation.  The pure form of a
chemical is a formulation consisting of 100 percent of that chemical. The commercial grade
form of a chemical is a formulation in which the chemical is almost 100 percent pure, but
contains minor impurities. A chemical is the sole active ingredient in a formulation if that
chemical is the only ingredient serving the function of the formulation. For instance, a pesticide
made for killing insects may contain a poison such as heptachlor as well as various solvent
ingredients which act as carriers or lend other desirable properties to the poison. Although all of
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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                                                                Hazardous Waste Identification - 13
these chemicals may be capable of killing insects, only the heptachlor serves the primary purpose
of the insecticide product. The other chemicals involved are present for other reasons, not
because they are poisonous.  Therefore, heptachlor is the sole active ingredient in such a
formulation even though it may be present in low concentrations.

As you can see, the P and U listings apply only to a very narrow category of wastes. For example,
an unused pesticide consisting of pure heptachlor is listed waste P059 when discarded.  An unused
pesticide consisting of pure toxaphene is listed waste P123 when discarded. An unused pesticide
made up of 50 percent heptachlor and 50 percent toxaphene as active ingredients, while being just
as deadly as the first two formulations, is not a listed waste when discarded.  That is because neither
compound is discarded in the form of a commercial chemical product. Why did EPA choose such
specific criteria for designating P- or U-listed chemicals as hazardous? When first developing the
definition of hazardous waste, EPA was not able to  identify with confidence all the different factors
that can cause a waste containing a known toxic chemical to be dangerous.  It was obvious,
however, those wastes consisting of pure, unadulterated forms of certain chemicals were worthy of
regulation. EPA used the P and U lists to designate hazardous wastes consisting of pure or highly
concentrated forms of known toxic chemicals. As you will see in the following sections of the
module, wastes that remain unregulated by listings may still fall under protective hazardous waste
regulation due to the four characteristics of hazardous waste.
2.4    CHARACTERISTIC HAZARDOUS WASTES

A hazardous waste characteristic is a property that indicates that a waste poses a sufficient threat to
deserve regulation as hazardous. EPA tried to identify characteristics which, when present in a
waste, can cause death or illness in humans or ecological damage. EPA also decided that the
presence of any characteristic of hazardous waste should be detectable by using a standardized test
method or by applying general knowledge of the waste's properties.  EPA believed that unless
generators were provided with widely available and uncomplicated test methods for determining
whether their wastes exhibited hazardous characteristics, this system of identifying hazardous
wastes would be unfair and impractical.  Given these criteria, EPA only finalized four hazardous
waste characteristics.  These characteristics are a necessary supplement to the hazardous waste
listings.  They provide a screening mechanism that waste handlers must apply to all wastes from all
industries.  In this sense, the characteristics provide a more complete and inclusive means of
identifying hazardous wastes than do the hazardous waste listings.  The four characteristics of
hazardous waste are:

      ignitability
      corrosivity
      reactivity
      toxicity.

The regulations explaining these characteristics and the test methods to be used in detecting their
presence are found in Part 261, Subpart C. Note that although waste handlers can use the test
methods referenced in Subpart C to determine whether a waste displays characteristics, they are
not required to do so.  In other words, any handler of industrial waste may apply knowledge of
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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14 - Hazardous Waste Identification
the waste's properties to determine if it exhibits a characteristic, instead of sending the waste for
expensive laboratory testing.  As with listed wastes, characteristic wastes are assigned waste
codes. 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

Ignitable wastes are wastes that can readily catch fire and sustain combustion.  Many paints,
cleaners, and other industrial wastes pose such a fire hazard.  Most ignitable wastes are liquid in
physical form.  EPA selected  a flash point test as the method for determining whether a liquid
waste is combustible enough to deserve regulation as hazardous. The flash point test determines
the lowest temperature at which a chemical ignites when exposed to flame. Many wastes in solid
or nonliquid physical form (e.g., wood, paper) can also readily catch fire and sustain combustion,
but EPA did not intend to regulate most of these nonliquid materials as ignitable wastes. A
nonliquid waste is only hazardous due to ignitability if it can spontaneously catch fire under
normal handling conditions and can burn so vigorously that it creates a hazard.  Certain
compressed gases and chemicals called oxidizers can also be ignitable. Ignitable wastes carry
the waste code D001 and are among the most common hazardous wastes.  The regulations
describing the characteristic of ignitability are codified at 261.21.

CORROSIVITY

Corrosive wastes are acidic or alkaline (basic) wastes which can readily corrode or dissolve
flesh, 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. EPA uses two
criteria to identify corrosive hazardous wastes. The first is a pH test.  Aqueous wastes with a pH
greater than or equal to 12.5, or less than or equal to 2 are corrosive under EPA's rules. A waste
may also be corrosive if it has the ability to corrode steel in a specific  EPA-approved test
protocol. Corrosive wastes carry the waste code D002. The regulations describing the
corrosivity characteristic are found at 261.22.

REACTIVITY

A reactive waste is one that readily explodes or undergoes violent reactions. Common examples
are discarded munitions or explosives. In many cases, there is no reliable test method to evaluate
a waste's potential to explode or react violently under common handling conditions.  Therefore,
EPA uses narrative criteria to define most reactive wastes and allows waste handlers to use their
best judgment in determining if a waste is sufficiently reactive to be regulated.  This is possible
because reactive hazardous wastes are relatively uncommon and the dangers they pose are well
known to the few waste handlers who  deal with them. A waste is reactive if it meets any of the
following criteria:

      it can explode or violently react when exposed to water, when  heated, or under
       normal handling conditions
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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                                                                Hazardous Waste Identification - 15
      it can create toxic fumes or gases when exposed to water or under normal
       handling conditions

      it meets the criteria for classification as an explosive under Department of
       Transportation rules

      it generates toxic levels of sulfide or cyanide gas when exposed to a pH range of 2
       through 12.5.

Wastes exhibiting the characteristic of reactivity are assigned the waste code D003.  The
reactivity characteristic is described in the regulations at 261.23.

TOXICITY CHARACTERISTIC

The leaching of toxic compounds or elements into groundwater drinking supplies from wastes
disposed of in landfills is one of the most common ways the general population can be exposed to
the chemicals found in industrial wastes. EPA developed a characteristic designed to identify wastes
likely to leach dangerous concentrations of certain known toxic chemicals into groundwater.  In
order to predict whether any particular waste is likely to leach chemicals into groundwater in the
absence of special restrictions on its handling, EPA first designed a lab procedure that replicates the
leaching process and other effects that occur when wastes are buried in a typical municipal landfill.
This lab procedure is known as the Toxicity Characteristic Leaching Procedure (TCLP).  Using the
TCLP on a waste sample creates a liquid leachate that is similar to the liquid EPA would expect to
find in the ground near a landfill containing the same waste. Once the leachate is created in the lab,
a waste handler must determine whether it contains any of 39 different toxic chemicals above
specified regulatory levels.  If the leachate sample contains a sufficient concentration of one of the
specified chemicals, the waste exhibits the toxicity characteristic (TC). EPA used groundwater
modeling studies and toxicity data for a number of common toxic compounds and elements to set
these threshold  concentration levels.  Much  of the toxicity data were originally developed under the
Safe Drinking Water Act.

However, there is one exception to using the TCLP to identify a waste as hazardous. The D.C.
Circuit Court, in Association of Battery Recyclers vs. EPA., vacated the use of the TCLP to determine
whether manufactured gas plant (MGP) wastes exhibit the characteristic  of toxicity.  As previously
stated, the TCLP replicates the leaching process in municipal  landfills. The court found that EPA
did not produce sufficient evidence that co-disposal of MGP wastes from remediation sites with
municipal solid waste (MSW) has happened or is likely to happen. On March 13, 2002, in response
to the court vacatur, EPA codified language exempting MGP waste from the toxicity characteristic
regulation (67 FR 11251).

To recap, determining whether a waste exhibits the toxicity characteristic involves two principal
steps: (1) creating a leachate sample using the TCLP; and (2)  evaluating the concentration of 39
chemicals in that sample against the regulatory levels listed below in Table 1.  If a waste exhibits the
TC, it carries the waste code associated with the compound or element that exceeded the regulatory
level. The following table presents the toxicity characteristic  waste  codes, regulated constituents,
and regulatory levels. This table and  the regulations describing the characteristic of toxicity are
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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16 - Hazardous Waste Identification
codified at 261.24.
                                            Table 1
           TOXICITY CHARACTERISTIC CONSTITUENTS AND REGULATORY LEVELS
Waste Code
D004
D005
D018
D006
D019
D020
D021
D022
D007
D023
D024
D025
D026
D016
D027
D028
D029
D030
D012
D031
D032
D033
D034
D008
D013
D009
D014
D035
D036
D037
D038
D010
D011
D039
D015
D040
D041
D042
D017
D043
Contaminants
Arsenic
Barium
Benzene
Cadmium
Carbon tetrachloride
Chlordane
Chlorobenzene
Chloroform
Chromium
o-Cresol*
m-Cresol*
p-Cresol*
Total Cresols*
2,4-D
1 ,4-Dichlorobenzene
1 ,2-Dichloroethane
1 , 1 -Dichloroethylene
2,4-Dinitrotoluene
Endrin
Heptachlor (and its epoxide)
Hexachlorobenzene
Hexachlorobutadiene
Hexachloroethane
Lead
Lindane
Mercury
Methoxychlor
Methyl ethyl ketone
Nitrobenzene
Pentachlorophenol
Pyridine
Selenium
Silver
Tetrachloroethylene
Toxaphene
Trichloroethylene
2,4,5-Trichlorophenol
2,4,6-Trichlorophenol
2,4,5-TP (Silvex)
Vinyl chloride
Concentration
5.0
100.0
0.5
1.0
0.5
0.03
100.0
6.0
5.0
200.0
200.0
200.0
200.0
10.0
7.5
0.5
0.7
0.13
0.02
0.008
0.13
0.5
3.0
5.0
0.4
0.2
10.0
200.0
2.0
100.0
5.0
1.0
5.0
0.7
0.5
0.5
400.0
2.0
1.0
0.2
        *If o-, m-, and p-cresols cannot be individually measured, the regulatory level for total
        cresols is used.
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                         But is an introduction to the topic used for training purposes.

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                                                               Hazardous Waste Identification - 17
2.5    WASTES LISTED SOLELY FOR EXHIBITING THE
       CHARACTERISTIC OF IGNITABILITY, CORROSIVITY, AND/OR
       REACTIVITY

Hazardous wastes listed solely for exhibiting the characteristic of ignitability, corrosivity, and/or
reactivity are not regulated the same way that other listed hazardous wastes are regulated under
RCRA. When wastes are generated that meet a listing description for one of the 29 wastes listed
only for exhibiting the characteristic of ignitability, corrosivity, and/or reactivity, the waste is not
hazardous if it does not exhibit a characteristic (66 FR 27266, 27283; May 16, 2001). This
concept is consistent with the mixture and derived-from rules, which will be discussed in detail
later in this module. For example, F003 is listed for the characteristic of ignitability. If a waste
is generated and meets the listing description for F003 but does not exhibit the characteristic of
ignitability, it is not regulated as a hazardous waste. However, such wastes are still subject to the
land disposal restrictions unless they do not exhibit a characteristic at the point of generation.
2.6    THE MIXTURE AND DERIVED-FROM RULES

So far, this module has introduced the fundamentals of the hazardous waste identification
process and an overview of the hazardous waste listings and characteristics. You should now be
able to explain in general terms which solid wastes are hazardous wastes. Now we analyze a
new question: "When do these hazardous wastes cease being regulated as hazardous wastes?"
The regulations governing this issue are commonly known as the mixture and derived-from
rules.

BACKGROUND

When EPA first developed the RCRA regulations and the definition of hazardous waste in the
late 1970s, the Agency focused on establishing the listings and characteristics, criteria allowing
industry to identify which wastes deserved regulation as hazardous wastes. Commenters on
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 this difficult
question, EPA developed a fairly simple and strict answer and presented it in the mixture and
derived-from rules.

LISTED HAZARDOUS WASTES

The mixture and derived-from rules operate differently for listed waste and characteristic wastes.
The mixture rule for listed wastes states that a mixture made up of any amount of a
nonhazardous solid waste and any amount of a listed hazardous waste is considered a listed
hazardous waste. In other words, if a small vial of listed waste is mixed with a large quantity of
nonhazardous waste, the resulting mixture bears the same waste code and regulatory status as the
original listed component of the mixture.  This principle applies regardless of the actual health

     The information in this document is not by any means a complete representation of EPA's regulations or policies,
                       But is an introduction to the topic used for training purposes.

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18 - Hazardous Waste Identification
threat posed by the waste mixture or the mixture's chemical composition. 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.  Thus, ash
produced by burning a listed hazardous waste bears that same waste code and regulatory status
as the original listed waste, regardless of the ash's actual properties.

The net effect of the mixture and derived-from rules for listed wastes can be summarized as
follows: once a waste matches a listing description, it is forever a listed hazardous waste,
regardless of how it is mixed, treated, or otherwise changed. Furthermore, any material that
comes in contact with the listed waste will also be considered listed, regardless of its chemical
composition.

Although the regulations do provide a few exceptions to the mixture and derived-from rules,
most listed hazardous wastes are subject to the strict principles outlined above. Why did EPA
create such a rigid system? To understand the logic behind the mixture and derived-from rules,
one must consider the circumstances under which EPA developed them. If EPA relied solely on
the narrative listing descriptions to govern when a waste ceased being hazardous, industry might
easily circumvent RCRA's protective regulation.  For example, a waste handler could simply mix
different wastes and claim that they no longer exactly matched the applicable hazardous waste
listing descriptions. These wastes would no longer be regulated  by RCRA, even though the
chemicals they contained would continue to pose the same threats to human health and the
environment.  EPA was not able to determine what sort of treatment or concentrations of
chemical constituents indicated that a waste no longer deserved regulation.  EPA therefore
adopted the simple, conservative approach of the mixture and derived-from rules, while
admitting that these rules might make some waste mixtures and treatment residues  subject to
unnecessary regulation.  Adopting the mixture and derived-from rules also presented certain
advantages. For instance, the mixture rule gives waste handlers  a clear incentive to keep their
listed hazardous wastes segregated from other nonhazardous or less dangerous wastestreams.
The greater the volume of hazardous waste, the more  expensive it is to store, treat and dispose.

CHARACTERISTIC WASTES

As mentioned previously, the mixture and  derived-from rules apply differently to listed and
characteristic wastes.  A mixture involving characteristic wastes is hazardous only if the mixture
itself exhibits a characteristic. Similarly, treatment residues and materials derived from
characteristic wastes are hazardous only if they themselves exhibit a characteristic. Unlike listed
hazardous wastes, characteristic wastes are hazardous because they possess one of four unique
and measurable properties.  EPA decided that once  a characteristic waste no longer exhibits one
of these four dangerous properties, it no longer deserves regulation as hazardous. Thus, a
characteristic waste can be made nonhazardous by treating it to remove its hazardous property;
however, EPA places certain restrictions on the manner in which a waste can be treated.  You
will learn more about these restrictions in the module entitled Land Disposal Restrictions.
Handlers who render characteristic wastes nonhazardous must consider these restrictions when
treating wastes to remove their hazardous properties.
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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                                                                 Hazardous Waste Identification - 19
WASTE LISTED SOLELY FOR EXHIBITING THE CHARACTERISTIC OF
IGNITABILITY, CORROSIVITY, AND/OR REACTIVITY

All wastes listed solely for exhibiting the characteristic of ignitability, corrosivity and/or
reactivity characteristic (including mixtures, derived-from, and as-generated wastes) are not
regulated as hazardous wastes once they no longer exhibit a characteristic (66 FR 27266, 27268;
May 16, 2001). EPA can list a waste as hazardous if that waste typically exhibits one or more of
the four hazardous waste characteristics.  If a hazardous waste listed only for the characteristics
of ignitability, corrosivity and/or reactivity is mixed with a solid waste, the original listing does
not carry through to the resulting mixture if that mixture does not exhibit any hazardous waste
characteristics. For example, EPA listed the F003  spent solvents as hazardous because these
wastes typically display the ignitability characteristic.  If F003 waste is treated by mixing it with
another waste, and the resulting mixture does not exhibit a characteristic, the F003 listing no
longer applies.  (Be aware, however, that for the land disposal restrictions, the Agency places
certain controls on how hazardous wastes can be treated or mixed with other wastes. Any
hazardous waste mixing must be consistent with these rules.)

If a waste derived from the treatment, storage, or disposal of a hazardous waste listed for the
characteristics of ignitability, corrosivity, and/or reactivity, no longer exhibits one of those
characteristics, it  is not a hazardous waste (261.3(g)(2)(ii)). For example, if a sludge is
generated from the treatment of F003, and that sludge does not exhibit the characteristic of
ignitability,  corrosivity, or reactivity, the F003 listing will not apply to the sludge.

MIXTURE RULE EXEMPTIONS

There are a few situations in which EPA does not require strict application of the mixture and
derived-from rules. EPA determined that certain mixtures involving listed wastes and certain
residues from the treatment of listed wastes typically do not pose enough of a health or
environmental threat to deserve regulation as listed wastes.  The principal regulatory exclusions
from the mixture  and derived-from rules are summarized below.

There are eight exemptions from the mixture rule.  The first exemption from the mixture rule
applies to mixtures of characteristic wastes and specific mining wastes excluded under
261.4(b)(7).  This narrow exemption allows certain mixtures to qualify as nonhazardous wastes,
even if the mixtures exhibit one or more hazardous waste characteristics. The module entitled
Solid and Hazardous Waste Exclusions will explain in more detail the mining waste or Bevill
exclusion.

The remaining exemptions from the mixture rule apply to certain listed hazardous wastes that are
discharged to wastewater treatment facilities (261.3(a)(2)(iv)). Many industrial facilities
produce large quantities of nonhazardous wastewaters as their primary wastestreams. These
wastewaters are typically discharged to a water body or local sewer system after being treated to
remove pollutants, as required by the Clean Water  Act. At many of these large facilities, on-site
cleaning, chemical spills, or laboratory operations also create relatively small secondary
wastestreams that are hazardous due to listings or characteristics. For example, a textile plant
producing large quantities of nonhazardous wastewater can generate a secondary wastestream of
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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20 - Hazardous Waste Identification
listed spent solvents from cleaning equipment. Routing such secondary hazardous wastestreams
to the facility's wastewater treatment system is a practical way of treating and getting rid of these
wastes.  This management option triggers the mixture rule, however, since even a very small
amount of a listed wastestream combined with very large volumes of nonhazardous wastewater
causes the entire mixture to be listed.  EPA provided exemptions from the mixture rule for a
number of these situations where relatively small quantities of listed hazardous wastes are routed
to large-volume wastewater treatment systems.  To qualify for this exemption from the mixture
rule, the amount of listed waste introduced into a wastewater treatment system must be very
small (or de minimis) relative to the total amount of wastewater treated in the system, and the
wastewater system must be regulated under the Clean Water Act.

DERIVED-FROM RULE EXEMPTIONS

There are five regulatory exemptions from the derived-from rule. The first of these derived-from
rule exemptions applies to materials that are reclaimed from hazardous wastes and used
beneficially. Many listed and characteristic hazardous wastes can be recycled to make new
products or be processed to recover usable materials with economic value.  Such products
derived from recycled hazardous wastes are no longer solid wastes. Using the hazardous waste
identification process discussed at the beginning of this module, if the materials are not solid
wastes, then whether they are derived from listed wastes or whether they exhibit hazardous
characteristics is irrelevant. The module entitled Definition of Solid Waste and Hazardous
Waste Recycling will explain which residues derived from hazardous wastes actually cease to be
wastes and qualify for this exemption.

The other four exemptions from the derived-from rule apply to residues from the treatment of
specific wastes  using specific treatment processes.  For example, K062 describes spent pickle
liquor from the  iron and steel industry. Pickle liquor is an acid solution used to finish the surface
of steel. When  pickle liquor is spent and becomes a waste, it usually contains acids and toxic
heavy metals. This waste can be treated by mixing it with lime to form a sludge.  This treatment,
called stabilization, neutralizes the acids in the pickle liquor and makes the metals less dangerous
by chemically binding them within the sludge. EPA studied this process and determined that
K062 treated in this manner no longer poses enough of a threat to warrant hazardous waste
regulation.  Therefore, lime-stabilized waste pickle liquor sludge derived from K062 is not a
listed hazardous waste. The other exemptions from the derived-from rule for listed wastes are
also quite specific and include: waste derived-from the burning of exempt recyclable fuels,
biological treatment sludge derived-from treatment of K156 and K157, catalyst inert support
media separated from K171 and K172, and residues from high temperature metal recovery of
K061, K062, and F006, provided certain conditions are met.

DELISTING

The RCRA regulations provide another form of relief from the mixture and derived-from rule
principles for listed hazardous wastes.  Through a site-specific process known as "delisting," a
waste handler can submit to EPA a petition demonstrating that while a particular wastestream
generated at their facility may meet a hazardous waste listing description, it does not pose
sufficient hazard to deserve RCRA regulation (260.22).  If EPA grants such a petition, the
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                       But is an introduction to the topic used for training purposes.

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                                                                Hazardous Waste Identification - 21
particular wastestream at that facility will not be regulated as a listed hazardous waste. Because
the delisting process is difficult, time-consuming, and expensive, it is not considered a readily
available exception to the mixture and derived-from from rules.

The hazardous waste listings, the hazardous waste characteristics, and the mixture and derived-
from rules are all essential parts of the definition of hazardous waste, but these key elements are
all described in different sections of the RCRA regulations.  Only one regulatory section, 261.3,
unites all four elements to establish the formal definition of hazardous waste.  This section is
entitled Definition of Hazardous Waste.  Section 261.3 states that all solid wastes exhibiting one
of the four hazardous characteristics defined in Part 261, Subpart C, are hazardous wastes.  This
section also states that all solid wastes listed on one of the four hazardous waste lists in Part 261,
Subpart D,  are hazardous wastes.  Finally, this section explains in detail the mixture and derived-
from rules and the regulatory exemptions from these rules.  Thus, although 261.3 is entitled
Definition of Hazardous Waste, it serves primarily as a guide to the mixture and derived-from
rules. Substantive rules about the two most crucial elements of the hazardous waste definition,
the listings and characteristics, are found elsewhere.
2.7    THE CONTAINED-IN POLICY

The contained-in policy is a special, more flexible version of the mixture and derived-from rules
that applies to environmental media and debris contaminated with hazardous waste.
Environmental media (singular, "medium") is the term EPA uses to describe soil, sediments, and
groundwater. Debris is a term EPA uses to describe a broad category of larger manufactured and
naturally occurring objects that are commonly discarded (268.2(g)). Examples of debris
include:

       dismantled construction materials such as used bricks, wood beams, and chunks of
       concrete

       decommissioned industrial equipment such as pipes, pumps, and dismantled tanks

      other discarded manufactured objects such as personal protective equipment (e.g., gloves,
       coveralls, eyewear)

      large, naturally  occurring objects such as tree trunks and boulders.

Environmental media and debris are contaminated with hazardous waste in a number of ways.
Environmental media are usually contaminated through accidental  spills of hazardous waste or
spills of product chemicals which, when spilled, become hazardous wastes. Debris can also be
contaminated through spills. Most debris in the form of industrial equipment and personal
protective gear becomes contaminated with waste or product chemicals during normal industrial
operations.  Contaminated media and debris are primary examples  of "remediation wastes." In
other words, they are not wastestreams created during normal industrial or manufacturing
operations.  They are typically created during cleanups of contaminated sites and during the
decommissioning of factories. Handlers of contaminated media and debris usually cannot
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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22 - Hazardous Waste Identification
control or predict the composition of these materials, which have become contaminated though
accidents or past negligence.  In contrast, handlers of "as-generated wastes," the term often used
to describe chemical wastestreams created during normal industrial or manufacturing operations,
can usually predict or control the creation of these wastes through the industrial process.
Examples of as-generated wastes include concentrated spent chemicals, industrial wastewaters,
and pollution control residues such as sludges.

The hazardous waste identification principles you have learned, including the mixture and
derived-from rules,  apply to as-generated industrial wastes.  EPA decided that a more flexible
version of these principles should apply to the primary remediation wastes: environmental media
and debris. In particular, EPA determined that strict application of the mixture and derived-from
rules was inappropriate for media and debris,  especially when listed wastes were involved.
Applying the mixture and derived-from rules to media and debris would present certain
disadvantages, as the following examples illustrate.  First, under the traditional mixture and
derived-from rules,  environmental media and debris contaminated with any amount of listed
hazardous waste would be forever regulated as hazardous.  Such a strict regulatory interpretation
would require excavated or dismantled materials to be handled as listed hazardous wastes and
could discourage environmental cleanup efforts.  Second, most spills of chemicals into soil or
groundwater produce very large quantities of these media containing relatively low
concentrations of chemicals.  Strict application of the mixture and derived-from principles to
media would therefore cause many tons of soil to be regulated as listed hazardous waste despite
containing low concentrations of chemicals and posing little actual health threat. Finally, one of
the main benefits of the mixture and derived-from rules is not relevant to media and debris. The
mixture and derived-from principles encourage handlers of as-generated wastes to keep their
listed wastes segregated from less hazardous wastestreams to avoid creating more listed wastes.
Handlers of contaminated media and debris generally have no control over the process by which
these materials come into contact with hazardous waste.

For all of the above reasons, EPA chose to apply a special, more flexible, version of the mixture
and derived-from rules to environmental media and debris.  Contaminated soil,  groundwater, and
debris can still present health threats if they are not properly handled and/or disposed.  Therefore,
EPA requires that any medium and debris contaminated with a listed waste or exhibiting a
hazardous characteristic be regulated like any other hazardous waste. Media and debris
contaminated with listed hazardous wastes can, however, lose their listed status and become
nonhazardous. This occurs after a demonstration that the particular medium or  debris in question
no longer poses a sufficient health threat to deserve RCRA regulation.  The requirements for
making this demonstration are explained below.  Once the demonstration is made, the medium or
debris in question is no longer considered to "contain"  a listed hazardous waste  and is no longer
regulated. In addition, contaminated media that contain a waste listed solely for the
characteristics of ignitability, corrosivity, and/or  reactivity, would no longer be  managed as a
hazardous waste when no longer exhibiting a  characteristic (66 FR 27266, 27286; May 16,
2001). This concept that media and debris can contain or cease to contain a listed hazardous
waste accounts for the name of the policy.

The contained-in policy for environmental media is not actually codified in the RCRA
regulations. In legal terms, it is merely a special  interpretation of the applicability of the mixture
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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                                                                Hazardous Waste Identification - 23
and derived-from rules to soil and groundwater that has been upheld in federal court. These
principles for the management of contaminated media are therefore known as a policy instead of
a rule. The terms of the contained-in policy are relatively general. In order for environmental
medium contaminated with a listed waste to no longer be considered hazardous, the handler of
that media must demonstrate to EPA's satisfaction that it no longer poses a sufficient health
threat to deserve RCRA regulation.  Although handlers of listed media must obtain EPA's
concurrence before disposing of such media as nonhazardous, the current contained-in policy
provides no guidelines on how this demonstration to EPA should be made.  The contained-in
policy is a far easier option for eliminating unwarranted hazardous waste regulation for low-risk
listed wastes than the process of delisting a hazardous waste mentioned previously.  The
delisting process demands extensive sampling and analysis, submission of a formal petition, and
a complete rulemaking by EPA.  A determination that an environmental medium no longer
contains a listed hazardous waste can be granted on a site-specific basis by EPA officials without
any regulatory procedure.

Debris contaminated with hazardous waste has traditionally been governed by the same
nonregulatory contained-in policy explained above.  In 1992, EPA codified certain aspects of the
contained-in policy for debris in the definition of hazardous waste regulations in  261.3(f) (57
FR 37194, 34225; August 18, 1992). In particular, EPA included a regulatory passage that
explains the process by which handlers of debris contaminated with listed hazardous waste can
demonstrate that the debris is nonhazardous.  This passage  also references certain treatment
technologies for decontaminating listed debris so that it no  longer contains a listed waste.  Thus,
the term contained-in policy is now something of a misnomer for contaminated debris, since a
contained-in rule for debris now exists.
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                        But is an introduction to the topic used for training purposes.

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24 - Hazardous Waste Identification
                     3.  REGULATORY DEVELOPMENTS
The hazardous waste identification process is subject to critical review, and adjusted accordingly
to reflect technology changes and new information.  The hazardous waste listings are particularly
dynamic as the Agency conducts further research to incorporate new listings.  The following is a
brief discussion of several developments to hazardous waste identification.
3.1    THE HAZARDOUS WASTE IDENTIFICATION RULES

EPA proposed to significantly impact the RCRA hazardous waste identification process through
a rulemaking effort called the Hazardous Waste Identification Rules (HWIR). The first rule,
HWIR-media,  was finalized on November 30, 1998, and addressed contaminated media (63 FR
65874). The second rule, HWTR-waste, was finalized on May 16, 2001, and modified the
mixture and derived-from rules, as well as the contained-in policy for listed wastes (66 FR
27266). Both the HWIR-media rule, and the HWIR-waste rule, attempt to increase flexibility to
the hazardous waste identification system by providing a regulatory mechanism for certain
hazardous wastes with low concentrations of hazardous constituents to exit the Subtitle C
universe.

The final HWIR-media rule addresses four main issues. First, the Agency promulgated a
streamlined permitting process for remediation sites that will simplify and expedite the process
of obtaining a permit.  Second, EPA created a new unit, called a "staging pile," that allows more
flexibility when storing remediation wastes during cleanups.  Third, the Agency promulgated an
exclusion for dredged materials permitted under the Clean Water Act, or the Marine Protection,
Research, and  Sanctuaries Act. Fourth, the rule finalized provisions that enable states to more
easily receive authorization when their RCRA programs are updated in order to incorporate
revisions to the federal RCRA regulations.  The HWIR-media rule did not incorporate the
provisions that would have removed low risk remediation waste from Subtitle C regulations
because of fundamental disagreements between stakeholders.

On July 18, 2000, the Agency released HWIR-waste exemption levels for 36 chemicals that were
developed using a risk model known as the Multimedia, Multipathway and Multireceptor Risk
Assessment (3MRA) Model (65 FR 44491). EPA is currently reviewing the public comments
and will decide whether further revisions to the model are necessary.  After completion of
independent testing, EPA submitted the model to EPA's Science Advisory Board  (SAB) for
review during 2003.

The May 16, 2001, HWIR-waste rule revised and retained the hazardous waste mixture and
derived-from rules as previously discussed in this module. In addition, the rule finalized
provisions that conditionally exempt mixed waste (waste that is both  radioactive and hazardous),
if the mixed waste meets certain conditions in Part 266 (66 FR 27266).
      The information in this document is not by any means a complete representation of EPA's regulations or policies,
                       But is an introduction to the topic used for training purposes.

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                                                               Hazardous Waste Identification - 25
3.2   FINAL HAZARDOUS WASTE LISTING DETERMINATIONS

EPA first signed a proposed consent decree with the Environmental Defense Fund (EDF) on
June 18, 1991, following a suit concerning EPA's obligations to take certain actions pursuant to
RCRA.  A consent decree is a legally binding agreement, approved by the Court, which details
the agreements of the parties in settling a suit. The proposed consent decree, commonly known
as the "mega-deadline," settles some of the outstanding issues from the case by creating a
schedule for EPA to take action on its RCRA obligations.  The consent decree, which has been
periodically updated, requires  EPA to evaluate specified wastestreams and determine whether or
not to add them to the hazardous waste listings.

On November 8, 2000, EPA listed as hazardous two wastes generated by the chlorinated
aliphatics industry (65 FR 67068). The two wastes are K174, wastewater treatment sludges from
the production of ethylene dichloride or vinyl chloride monomer (EDC/VCM), and K175,
wastewater treatment sludges from the production of vinyl chloride monomer using mercuric
chloride catalyst in an acetylene-based process. For K174, EPA finalized a contingent-
management listing approach which specifies that the waste will not be listed if it is sent to a
Subtitle C landfill or a non-hazardous landfill licensed or permitted by the state or federal
government.

On November 20, 2001, EPA published a final rule listing three wastes generated from inorganic
chemical manufacturing processes as hazardous wastes (66 FR 58257). The three wastes are
K176, baghouse filters from the production of antimony oxide; K177, slag from the production
of antimony oxide that is speculatively accumulated or disposed; and K178, residues from
manufacturing and manufacturing-site storage of ferric chloride from acids formed during the
production  of titanium dioxide using the chloride-ilmenite process.

EPA proposed a concentration-based hazardous waste listing for certain waste solids and liquids
(K180 and K179) generated from the production of paint on February 13, 2001 (66 FR 10060).
Following a review of the public comments and supplemental analyses based on those public
comments,  EPA determined that the paint wastes identified in the proposal do not present a
substantial  hazard to human health or the environment. Therefore, EPA did not list these paint
production  wastes as hazardous. See the April 4, 2002, final determination regarding these
hazardous waste listings (67 FR 16261) for additional information.

On February 24, 2005, EPA published a final rule listing nonwastewaters from the production of
certain dyes, pigments, and food, drug, and cosmetic colorants (70 FR 9138) as hazardous
(K181) using a mass loading-based  approach. Under the mass loading approach, these wastes
are hazardous if they contain any of the constituents of concern at annual mass loading levels
that meet or exceed the regulatory levels. The K181 listing focuses on seven hazardous
constituents: aniline, o-anisidine, 4-chloroaniline, p-cresidine, 1,2-phenylenediamine, 1,3-
phenylenediamine, and 2,4-dimethylaniline.  Waste that contains less than the specified threshold
levels of constituents of concern are not hazardous. The K181 listing is EPA's final obligation
under the consent decree.
     The information in this document is not by any means a complete representation of EPA's regulations or policies,
                       But is an introduction to the topic used for training purposes.

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26 - Hazardous Waste Identification
3.3    PROPOSED REVISION TO WASTEWATER TREATMENT
       EXEMPTION FOR HAZARDOUS WASTE MIXTURES

On April 8, 2003, EPA proposed to add benzene and 2-ethoxyethanol to the list of solvents
whose mixtures with wastewater are exempted from the definition of hazardous waste (68 FR
17234). EPA is proposing to provide flexibility in the way compliance with the rule is
determined by adding the option of directly measuring solvent chemical levels at the headworks
of the wastewater treatment system.  In addition, EPA is proposing to include scrubber waters
derived from the combustion of spent solvents to the headworks exemption. Finally, EPA is
proposing to extend the de minimis exemption to wastes listed in 261.31 and 261.32 when
released in de minimis quantities and to non-manufacturing facilities if certain conditions are
met. The final rule is scheduled to be published in the Fall of 2005.
     The information in this document is not by any means a complete representation of EPA's regulations or policies,
                       But is an introduction to the topic used for training purposes.

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