United States Solid Waste and
Environmental Protection Emergency Response EPA530-F-94-018
Agency (5305) May 1994
RCRA Policy Statement
Clarification of the Land
Disposal Restrictions'
Dilution Prohibition and the
Combustion of Inorganic
Metal-bearing Hazardous
Waste
Recycled/Recyclable
7"^. ~\S Printed on paper that contains at
\ZJvI7 least 50% post-consumer recycled fiber
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NOTE: This document is intended to be an information resource. It may contain
errors, omissions, etc; and therefore should not be used in lieu of the Federal
Register or Code of Federal Regulations for purposes of compliance. We
regret any inconvenience these errors or omissions may cause. If you have
any questions or to obtain additional information, please call, EPA's TSCA
Assistance Information Service at (202) 554-1404 or (202) 488-3821.
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
MAT 23199*
OFFICE OF
SOLID WASTE AND EMERGENCY RESPONSE
MEMORANDUM
SUBJECT:
RCRA Policy Statement: Clarification of the Land
Disposal Restrictions1 Dilution Prohibition and
Combustion of Inorganio«Metal-Bearing Hazardous Wastes
I - X
PROM: Elliott P. Law
Assistant Admin
TO: Waste Management Division Directors, Regions
I. introduction
A. Purpose
This memorandum sets out a Statement of Policy under th*
Resource Conservation and Recovery Act (RCRA) clarifying the
application of the Land Disposal Restrictions ^(LDR) prohibition
on dilution (see 40 CFR S 268.3) to combustion of certain
inorganic metal-bearing hazardous wastes. Because combustion
normally does not represent effective treatment of these wastes,
such burning can be considered impermissible dilution. In such
cases, these hazardous metal-bearing wastes cannot be combusted
legally. This Policy Statement clarifies the general situation
regarding combustion of these metal-bearing hazardous wastes, but
application of this policy will vary depending on particular
circumstances.
B. Regulatory Background
Under RCRA, the LDR prohibition on dilution states generally
that no parson "shall in any way dilute a restricted waste ... as
a substitute for adequate treatment to achieve compliance with [a
treatment jacandard for that waste]". 40 CFR 268.3(a). This
prohibitidllf iMplements the requirement of section 3004 (m) of
RCRA, whicfc- r«Kjuir«8 that hazardous constituents in hazardous
wastes be destroyed, removed or immobilized before these wastes
can be land disposed. Hazardous constituents are not destroyed,
removed or immobilized if they are diluted. Chemical Waste
Management v. EPA. 976 F.2d 2, 16, 17, 19-20 (D.C. Cir. 1992),
1 Combustion for purpose* of this memo does not include tMtal
recovery unit» engaged in metal reclamation or vitrification units engaged in
metal stabilization.
Print* on Recycled Paper
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cert, denied 113 S.Ct. 1961 (1993); see also S. Rep. No. 298,
98th Cong. 1st Sess. 17 (1983) ("the dilution of wastes by the
addition of- other hazardous waste or any other materials during
waste handling, transportation, treatment or storage is not an
acceptable method of treatment to reduce the concentration of
hazardous constituents").
Consistent with these authorities, the Agency has stated
that the dilution prohibition serves one chief purpose— "to
ensure that prohibited wastes are treated by methods that are
appropriate for that type of waste." 55 FR at 22532 (June 1,
1990). Impermissible dilution can occur under a number of
circumstances. The most obvious is when solid wastes are added
to a prohibited waste to reduce concentrations but not volumes of
hazardous constituents, or to mask their presence. Impermissible
dilution also may occur when wastes not amenable to treatment by
a certain method (i.e., treated very ineffectively by that
treatment method) are nevertheless 'treated1 by that method. 55'
ER 22666 (June 1, 1990) (biological treatment does not
effectively remove toxic metals from wastes; therefore,
prohibited wastes with .treatment standards for metals ordinarily
would be impermissibly diluted if managed in biological treatment
systems providing no separate treatment for the metals). See
also 52 FR at 25778-79 (July 8, 1987) (impoundments which
primarily evaporate hazardous constituents do not qualify as
section 3005(j)(11) impoundments which may receive otherwise-
prohibited hazardous wastes that have not met the treatment
standard).
EPA is providing guidance today clarifying how the LDR
dilution prohibition could apply to certain inorganic metal-
bearing hazardous wastes that may be placed in combustion units,
other than metal recovery furnaces.
II.
General Distinction Between "Adequate Treatment" and
Potential Violations of the Dilution Prohibition
This memorandum deals with the question of whether
combustion of prohibited inorganic hazardous wastes can be a type
of impermissible dilution. An "inorganic hazardous waste" is one
for which EPA has established treatment standards for metal
hazardous constituents, and which does not otherwise contain
significant organic or,cyanide content (see further discussion,
last paragraph page 3, clarifying what constitutes an
insignificant organic or cyanide content).
* A "prohibited" hazardous waate La one which La actually subject to
a prohibition on land disposal without first being treated, or disposed in a
no-migration unit. See 54 FR 36968 (Sept. 6, 1989).
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The Agency has evaluated the listed wastes and has
determined that 44 of the RCRA listed wastes (as set forth in 40
CFR § 261)'typically appear to be such inorganic hazardous
wastes; i.e., they typically do not contain organics, or contain
only insignificant amounts of organics, and are not regulated for
organics (see Appendix A to this memorandum for a list of these
wastes). The Best Demonstrated Available Technology (BOAT) for
these inorganic, metal-bearing listed wastes is metal recovery or
stabilization. Thus, impermissible dilution may result when
these wastes are combusted.
There are eight characteristic metal waste codes; however,
only wastes that exhibit both the toxicity characteristic (TC)
and the extraction procedure (EP) for D004 - D011 are prohibited
now (see 55 FR 22660-02, June 1, 1990). Characteristic wastes,
of course, cannot be generically characterized as easily as
listed wastes because they can be generated from many different .
types of processes. For example, although some characteristic
metal wastes do not contain organics or cyanide or contain only
insignificant amounts, others may have organics or cyanide
present which justify combustion, such as a used oil exhibiting
the TC characteristic for a metal. Thus, it is difficult to say
which D004-D011 wastes would be impermissibly diluted when
combusted, beyond stating that as a general matter, impermissible
dilution would occur if the DO04-DO11 waste does not have
significant organic or cyanide content but is nevertheless
combusted.
EPA ordinarily would not consider the following hazardous
wastes to be strictly inorganic (or to contain "significant
organic or cyanide content") for which combustion would otherwise
be impermissible dilution. Combustion of the following wastes is
therefore not prohibited under the LDR dilution prohibition: (1)
any of the 44 listed wastes and 8 characteristic wastes in
Appendix A that, at point of generation, or after any bona fide
treatment such as cyanide destruction prior to combustion,
contain hazardous organic constituents or cyanide at levels
exceeding the constituent-specific treatment standard for F039,
which represents a compilation of numerical limits for hazardous
constituents; (2) organic, debris-like materials (e.g., wood,
paper, plastic, or cloth) contaminated with an inorganic metal-
bearing hazardous waste; and (3) any of the 44 listed wastes and
8 characteristic wastes that, at point of generation, have
reasonable heating value such as greater than or equal to 5000
Btu (see 48 FR 11157 (March 16, 1983)). The foregoing three
categories of waste typically would contain sufficient organic
3 To the extent that these wastes or residues of these wastes (i.e.,
biological treatment sludges) contain significant organic content, combustion
may be an appropriate treatment technology. See later discussion regarding
this point. '
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content to indicate that combustion can be a reasonable means of
treating the wastes prior to land disposal. However, as noted
above, mixing practices such as fuel blending to add organics to
inorganic i&etal-bearing hazardous wastes ordinarily would be
considered to be impermissible dilution. This is because the
dilution prohibition applies at the point a hazardous waste is
generated. Chemical Waste Management v. EPA. 976 F.2d at 22-3;
also 48 FR 11158, 11159 and nn. 2 and 4 (March 16, 1983); 53 FR
at 522 (Jan. 8, 1988) (determinations of legitimacy of recycling
are made on a waste-by-waste basis before any blending occurs).
This Policy Statement is also reflective of the Agency's
concerns about the hazard presented by toxic metals in the
environment. When an inorganic metal-bearing hazardous waste
with insignificant organics is placed in a combustion unit,
legitimate treatment for purposes of LDR ordinarily is not
occurring. No treatment of the inorganic component occurs during
combustion, and therefore, metals are not destroyed, removed, or
immobilized. Since there are no significant concentrations of
organic compounds in inorganic metal-bearing hazardous wastes, it
cannot be maintained that the waste is being properly or
effectively treated via combustion (i.e., thermally treated or
destroyed, removed, or immobilized).
In terms of the dilution prohibition, if combustion is
allowed as a method to achieve a treatment standard for these
wastes, metals in these wastes will be dispersed to the ambient
air and will be diluted by being mixed in with combustion ash1
from other waste streams. Adequate treatment (stabilization or
metal recovery to meet LDR treatment standards) has not been
performed and dilution has occurred. It is also inappropriate to
regard eventual stabilizing of such combustion ash as providing
adequate treatment for purposes of the LDRs. Simply meeting the
numerical BOAT standards for the ash fails to account for metals
in the original waste stream that were emitted to the air and for
reductions achieved by dilution with other materials in the ash.
(In most cases, of course, the metal-bearing wastes will have
been mixed with other wastes before combustion, which mixing
itself could be viewed as impermissible dilution).
These inorganic, metal-bearing hazardous wastes should be
and are usually treated by metal recovery or stabilization
technologies-. These technologies remove hazardous constituents
through recovery in products, or immobilize them, and are
therefore permissible BOAT treatment methods. However, EPA
believes that this statement of policy clarifying application of
LDR dilution prohibition is needed because we have observed that
some of these wastes may be going to conventional combustion
devices such as incinerators or cement kilns. For example, some
owners/operators may be willing to accept inorganic lead wastes
with insignificant organics at their combustion facilities (which
can still apparently meet their air emissions limits at the
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stack). As explained above, land disposal of combustion
residuals from these facilities would typically violate the land
disposal restrictions prohibition on dilution. Combustion is not
usually an appropriate treatment for these wastes because
hazardous constituents are not removed, destroyed, or
immobilized.
Consequently, the general principles set out in this
memorandum, subject to appropriate consideration of individual
circumstances, are: (l) that a prohibited inorganic metal-
containing hazardous waste (listed in Appendix A to this
memorandum) without significant organic content can be considered
to be diluted impermissibly when combusted (even if the treatment
standards for metals are achieved in part by subsequent treatment
of combustion ash); and (2) that the determination of whether a
waste is an inorganic metal-bearing hazardous waste is made at
the point of generation . This means that, ordinarily, such a
waste would be considered to be diluted impermissibly even if it
is blended with organic wastes for which combustion would
otherwise be an appropriate treatment method.
This is the point at which the waste becomes hazardous.
(See 45 FR 33095-33096, May 19, 1980).
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r
I Waste Cod*
1 F006 5*
1 F007 *
1 F008 *
F009 *
1 F010 *
F011 *
1 F012 *
I F019 *
Listed Wastes
Wastewater treatment sludges from electroplating
operations except from the following processes:
(1) sulfuric acid anodizing of aluminum; (2) tin
plating carbon steel; (3) zinc plating
(segregated basis) on carbon steel; (4) aluminum
or zinc-plating on carbon steel; (5)
cleaning/ stripping associated with tin, zinc and
aluminum plating on carbon steel; and (6)
chemical etching and milling of aluminum.
Spent cyanide plating bath solutions from
electroplating operations .
Plating bath residues from the bottom of plating
baths from electroplating operations where
cyanides are used in the process.
Spent stripping and cleaning bath solutions from
electroplating operations where cyanides are
used in the process.
Quenching bath residues from oil baths from
metal treating operations where cyanides are
used in the process.
Spent cyanide solutions from salt bath pot
cleaning from metal heat treating operations.
Quenching waste water treatment sludges from
metal heat treating operations where cyanides
are used in the process.
Wastewater treatment sludges from the chemical
conversion coating of aluminum except from
zirconium phosphating in aluminum car washing
when such phosphating is an exclusive conversion
coating process.
1
K002
K003
Wastewater treatment sludge from the production
of chrome yellow and orange pigments.
Wastewater treatment sludge from the production
of molybdate orange pigments.
Assuming wastes do not contain treatable
concentrations .of cyanide.
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Waste Code
K004
K005
K006
K007
K008
K061
K069
K071
K100
K106
Listed Wastes
Wastewater treatment sludge from the production
of zinc yellow pigments.
Wastewater treatment sludge from the production
of chrome green pigments.
Wastewater treatment sludge from the production
of chrome oxide green pigments (anhydrous and
hydrated) .
Wastewater treatment sludge from the production
of iron blue pigments.
Oven residue from the production of chrome oxide
green pigments.
Emission control dust/sludge from the primary
production of steel in electric furnaces.
Emission control dust/sludge from secondary lead
smelting.
Brine purification muds from the mercury cell
processes in chlorine production, where
separately prepurified brine is not used.
Waste leaching solution from acid leaching of
emission control dust/sludge from secondary lead
smelting.
Sludges from the mercury cell processes for
making chlorine.
P010
P011
P012
P013 *
P015
P029 *
P074 *
P087
P099
P104 *
Arsenic acid H,AsOA
Arsenic oxide As,O,
Arsenic trioxide
Barium cyanide
Beryllium
Copper cyanide Cu(CN)
Nickel cyanide Ni(CN),
Osmium tetroxide
Potassium silver cyanide
Silver cyanide
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Waste Cod*
P113
P114
P115
P119
P120
P121 *
P122
Listed Wastes
Thallic oxide
Thallium (1) selenite
Thallium (1) sulfate
Ammonium vanadate
Vanadium oxide V,O,
Zinc cyanide
Zinc phosphide
U032
UI45
U151
U204
U205
U216
Calcium chromate
Lead phosphate
Mercury-
Selenious acid
Selenium disulfide
Thallium (I) chloride
Thallium (I) nitrate
Waste Code
D004
D005
D006
D007
D008
D009
D010
D011
Characteristic Wastes
Arsenic
Barium
Cadmium
Chromium
Lead
Mercury
Selenium
Silver
8
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