0?k/K 8?
Thursday
March 29 1990
Part \\
Environmental
Protection Agency
40 CFR Part 261 et ai.
Hazardous Waste Management System;
identification and Listing of Hazardous
Waste; Toxicity Characteristics Revisions;
Final Rule
Printed on Recycled Paper
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11793 Federal Register / Vol. 55, No. 61 / Thursday, March 29. 1990 /. Rules and Regulations
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Parts 261,264,265,268,271,
and 302
[SWH-FRL-3601-i; EPA/OSW-FR-89-026]
BIN 2050-AA78
Hazardous Waste Management
System; Identification and Listing of
Hazardous Waste; Toxicity
Characteristics Revisions
AGENCY: Environmental Protection -
Agency.
ACTION: Final rule.
SUMMARY: On June 13,1986, the
Environmental Protection Agency (EPA)
proposed to revise the existing toxicity
characteristics, which are used to
identify those wastes defined as
hazardous and which are subject to
regulation under subtitle C of the
Resource Conservation and Recovery
Act (RCRA) due to their potential to
leach significant concentrations of
specific toxic constituents. The proposed
rule was designed to refine and broaden
the scope of the hazardous waste
regulatory program and to fulfill specific
statutory mandates under the
Hazardous and Solid Waste
Amendments of 1084 (HSWA).
EPA is today promulgating the
Toxicity Characteristics (TC). Today's
rule retains many of the features of the
original proposal: It replaces the
Extraction Procedure (EP) leach test
with the Toxicity Characteristic
Leaching Procedure (TCLP); it adds 25
organic chemicals to the list of toxic
constituents of concern; and it
establishes regulatory levels for these
organic chemicals based on health-
based concentration thresholds and a
dilution/attenuation factor that was
developed using a subsurface fate and
transport model. In response to
comments received on the proposed rule
and related notices, the final rule
incorporates a number of modifications
in the leaching procedure, the list of
toxicants, the chronic toxicity reference
levels, and the fate and transport model.
The overall effect of today's action
will be to subject additional wastes to
regulatory control under subtitle C of
RCRA, thereby providing for further
protection of human health and the
environment.
DATES: Effective Date: September 25,
1990.
Compliance Dates: Large quantity
generators: September 25,1990. Small
quantity generators (SQGs): March 29,
1991. Any person that would like to use
the Toxicity Characteristic Leaching
Procedure (TCLP) before the effective
date may do so in order to determine
whether the eight heavy-, metals and six
pesticides that are currently regulated
under the Extraction Procedure (EP)
Toxicity Characteristic leach at levels of
regulatory concern.
ADDRESSES: The official record for this
rulemaking (Docket Number F-90-TCF-
FFFFF) is located in the EPA RCRA
Docket (Second Floor, Rm 2427), U.S.
Environmental Protection Agency, 401M
Street SW., Washington, DC 20460. The
docket is open from 9:00 a.m. to 4:00
p.m., Monday through Friday, excluding
federal holidays. The public must make
an appointment to review docket
materials by calling (202) 475-9327. The
public may copy material at a cost of
$0.15 per page.
FOR FURTHER INFORMATION CONTACT:
For general information about this
rulemaking, contact the RCRA/
Superfund Hotline at (800) 424-9346 (toll
free) or (202) 382-3000 in the
Washington, DC metropolitan area. For
information on specific aspects of this
rule, contact Steve Cochran, Office of
Solid,Waste (OS-332), U.S.
Environmental Protection Agency, 401M
Street SW., Washington, DC 20460, (202)
475-8551.
SUPPLEMENTARY INFORMATION
Preamble Outline
I. Authority
II. Background
A. Definition of Hazardous Waste
B. Existing Extraction Procedure Toxicity
Characteristic
C. The Hazardous and Solid Waste
Amendments of 1984
D. Previous Federal Register Notices
E. Other Notices Relating to the Proposal
F. Pollution Prevention
G. Summary of Final Rule
III. Response to Major Comments and
Analysis of Issues
A. General Approach
1. Expanded Use of Hazardous Waste , ,
Characteristics
2. Mismanagement Scenario ,
a. Extent to Which Scenario is Reasonable
b. Worst-Case Scenario Selection
c. Extent to Which the Mismanagement
Scenario for Wastes Managed in Surface
Impoundments is Appropriate
3. Targeted Risks
4. Accuracy
5. Solvent Override
B. Constituents of Concern
1. Final List of Constituents'
2. Toxicants Versus Indicator Parameters
3. Method for Selecting Constituents
4. Specific Organic Constituents
a. Vinyl Chloride
b. Bis(2-chloroethyl) Ether
c. Toxaphene
d. Phenol .
e. Pentachloiophenol.
5. Specific Inorganic Constituents
.a. Silver
b. Chromium,. .
c. Nickel and Thallium
C. Chronic Toxidty Reference. Levels
1. Maximum Contaminant Levels
2. Risk-Specific Doses .for Carcinogenic
Constituents '
3. Apportionment of Health Limits
D. Use of Generic Dilution/Attenuation
Factors (DAFji)
.E. Application of a Subsurface Fate and
Transport Model
1. Introduction •
a. June 13,1986, Proposed Rule (51FR
21648)
b. August 1,1908, Notice of Data
Availability and Request for Comments;
Supplement to Proposed Rule (52 FR
28892)
2. Modifications of the Subsurface Fate and •
Transport Model (EPASMOD) in
Response to Comments
•a. General Modifications
i. Unsaturated Zone
ii. Source Characterization
iii. Treatment 6f Dilution from Recharge
, iv. Location of the Receptor Well
v. Dispersivity Values
, vi. Hydraulic Conductivity
vii.Hydrolysis
• viii. Steady-State Assumption
ix. Biodegradation
x. Summary of General Modifications
b. Use of the EP ACML for Surface
Impoundments
3, Newly Acquired .Data
a. Landfill Data
b. .Chemical-Specific Parameters
4. DAF Evaluation
a. Selection of an Appropriate Percentile
b. Resulting DAFs for Landfills
c. Resulting DAFs for Surface
, Impoundments
d, Final DAF Selection
F. Toxicity Characteristic Leaching
Procedure (TCLP) (Method 1311)
1. Introduction
2. Adoption in the LDR Rulemaking and
Modification from the Proposed Rule
3. Applicability of TCLP to Solidified
Waste
4. Analytical Methods
G. Testing and Recordkeeping
Requirements
1. Existing Requirements for Generators
2. Changes Considered
H. Applicability to Wastes Managed in
Surface Impoundments
1. Sampling Point
2. Multiple Surface Impoundments
I. Relationship to Other RCRA Regulations
1. Hazardous Waste Identification
Regulations
a. Hazardous Waste Listings
b. "Mixture" and "Derived From" Rules
c. Mixture Rule Exemption
• d. Delisting ' • •
2. Land Disposal Restrictions
a. Risk Levels and Frequency Interval
b'. Treatment Standards for TC Wastes
c. Schedule for LDR Determinations
3. RCRA Corrective Action and Closure
Requirement!)
4. Minimum Technology Requirements •
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Federal Register / Vo!, 55, No. 61 /.Thursday, March 29, 1990 /Rules and Regulations 11799
a. Applicability
b. Scope of Minimum Technology
Requirements
1. Permitted Facilities
2. Interim Status Facilities
o. Compliance with Minimum Technology
Requirements
5. RCRA Subtitle D (Solid Wastes)
a. Municipal Waste Combustion Ash
b. Impact on Wastes Excluded from
Subtitle C Regulation
6. RCRA Subtitle I (Underground Storage
Tanks)
a. Scope of the Underground Storage Tank
Program
b. Deferral for Petroleum-Contaminated
Media and Debris Subject to Part 280
Corrective Action Requirements
7. RCRA Section 3004(n) Air Regulations
J. Relationship to Other Regulatory
Authorities
1. Comprehensive Environmental
Response, Compensation, and Liability
Act(CERCLA)
2. Clean Water Act
a. Conflict with NPDES Effluent Guidelines
and Pretreatment Standards
b. Permit Requirements for Wastewater
Treatment Facilities . ,
c. Sludges from Publicly Owned Treatment
Works (POTW)
3. Safe Drinking Water Act
4. Federal Insecticide, Fungicide, and '
Rodenticide Act (FIFRA)
a. Pesticide Wastes
b. Treated Wood Wastes
5. Food, Drug, and Cosmetic Act (FDCA)
a. Food Wastes
b. Pharmaceutical and Cosmetic Wastes
6. Used Oil Recycling Act
7. Toxic Substances Control Act (TSCA)
K. Implementation Issues
1. Notification
2. Effective Date
3. Permitting
IV. Regulatory Levels
A. List of Constituents
1. Proposed List ,
2. Constituents for Which Final Regulatory
Levels Are Not Now Being Promulgated
3. Final List of Constituents
a. Organic Constituents
b. Inorganic Constituents
B. Selection of DAFs , ,
C. Analytical Constraints
D. Final Regulatory Levels
V.. Implementation
A. State Authority !
1. Applicability of Final Rule in Authorized
States , .
2. Effect on State Authorization'
B. Integration of Today's Final Rule with
Existing EPTC
t. Facilities Located in Authorized States
2. Facilities Located in Unauthorized States
C» Notification
D. Permitting
E. Compliance Date
VI. Regulatory Requirements '_
A. Introduction
B. Regulatory Impact Analysis
1.'Executive Order No. 12291
2. Basic Approach ' ,
3. Methodology
a. Determination of Affected Wastes and
Facilities
b. Cost Methodology
1. Social Costs
2. Compliance Costs
a Economic Impact Methodology
d. Benefits Methodology
1. Human Health Risk Reduction
2. Resource Damage Avoided
3. Cleanup Costs Avoided
. e. Used Oil Methodology
4. Results
a. Affected Wastes and Facilities '
1. Affected Wastes
2. Affected Facilities
3. Sensitivity Analysis of Affected Wastes
and Facilities
b. Cost Results
1. Social Costs and Compliance Costs
2. Sensitivity Analysis of Costs
C; Economic Impact Results
1. Significantly Affected Facilities
2. Effects on Product and Capital Market"
3. Sensitivity Analysis of Economic
Impacts
d. Benefits Results
1. MEI Risk
2. Population Risk
3. Resource Damage
4. Cleanup Costs Avoided
5. Sensitivity Analysis of Benefits
e. Cost Effectiveness
f. Used Oil Results
C. Regulatory Flexibility Analysis
1. Approach
2. Results
D. Response to Comments on RIA for June
, 13,1986, Proposal
1. Industries Included in the Analysis
2. Estimation of Costs and Economic
Impacts.
3. Estimation of Benefits
4. Cost-Benefit Comparisons
5. Small Business Analysis
E. Paperwork Reduction Act
VII. References
I. Authority
The amendments to the hazardous
waste regulations in 40 CFR parts 261
and 271 are being promulgated under the
authority of sections 1006, 2002(a). 3001,
3002, and 3006 of the Solid Waste
Disposal Act of 1970, as amended by the
Resource Conservation and Recovery
Act of 1976, as amended (42 U.S.C. 6905,
6912(a), 6921, 6922, and 6926). The
amendments to the list of hazardous
substances and reportable quantities in
40 CFR part 302 are being promulgated
under the authority of section 102 of the
Comprehensive Environmental
Response, Compensation, and Liability
Act of 1980 (42 U.S.C. 9602), as
amended, and sections 311- and 501{a) of
the Federal Water Pollution Control Act
(33 U.S.C. 1321 and 1361).
U. Background
A. Definition of Hazardous Waste
Subtitle C of the Resource
Conservation and Recovery Act
(RCRA), as amended, establishes a
federal program for the comprehensive
regulation of hazardous waste. Section
1004(5) of RCRA defines hazardous
waste, among other things, as solid
waste that may ". . , pose a substantial
present or potential hazard to human
health and the environment when
improperly treated, stored, transported,
disposed, or otherwise managed." Under
RCRA Section 3001, EPA is charged with.
defining which solid wastes are
hazardous by either identifying the
characteristics of hazardous Waste or
listing particular hazardous wastes.
Identifying characteristics of hazardous
waste and listing hazardous wastes are
distinct and fundamentally different
mechanisms for defining hazardous
wastes.
The hazardous waste characteristics
promulgated by EPA designate broad
classes of wastes which are clearly
hazardous by virtue of ah inherent
property. In the May 19,1980 final rule
(45 FR 33084) that instituted EPA's
general framework for identifying
hazardous waste, the Agency
established two basic criteria for
identifying hazardous waste
characteristics: (1) The characteristic
should be capable of being defined in
terms of physical, chemical, or other :
properties which cause the waste to
meet the statutory definition of
hazardous waste; and (2) the properties
defining the characteristic must be
measurable by standardized and
available testing protocols or
reasonably detected by generators
through their knowledge bf-tHe waste (40
CFR 261.10). In the May 19,1980 final
rule, EPA stated that it adopted the
second criterion in recognition that the
primary responsibility for determining
whether wastes exhibit hazardous
characteristics rests with generators, for
whom .standardization and availability
of testing protocols are essential.
The 'approach EPA uses to establish
hazardous waste characteristics is to
determine which properties of a waste
would result hi harm to human health or
the environment if a waste is
mismanaged. The Agency then
establishes test methods and regulatory
levels for each characteristic property;
solid waste that exceeds the regulatory
level for any characteristic property is a
hazardous waste.
The regulatory levels foe
characteristics that have been
established provide a high degree oi
certainty that wastes exceeding those
regulatory levels would pose hazards to
human health and the environment if
improperly managed and therefore
require regulation under subtitle'C.
Wastes that do not exhibit hazardous
waste, characteristics are not necessarily
nonhazardpus. The Agency may
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Mardi 29, 1.990 / Rules and Regulations
evaluate wastes from either specific or
nonspecific sources and decide to list
them as hazardous wastes based on
criteria defined in 40 CFR 261.11.
To list a waste as hazardous,'EPA
conducts a detailed industry or process
study involving literature reviews,
engineering analyses, surveys and
questionnaires, site visits, and waste
sampling. For listing, the Agency places
particular emphasis on hazardous
constituents contained in specific
wastes generated by the industry of
process being studied (See 40 CFR
281.11(a)(3)). However, EPA uses a
comparatively flexible approach when
deciding to list wastes as hazardous; the
approach includes consideration of
factors such as type of threat posed,
plausible ways that the waste might be
mismanaged, migration potential and
persistence in the environment, waste
quantity, and actions of other regulatory
programs. The Agency also promulgated
two other rules for identifying solid
wastes as hazardous wastes—the
mixture and derived-from rules. The
mixture rule says that any mixture of a
listed hazardous waste and a solid
waste is the listed hazardous waste (40
CFR 261.3fa)(2HiiiHJv)); the derived-
from rule says that any solid waste
derived from the treatment, storage, or
disposal of a listed hazardous waste is
considered the listed hazardous waste
(40CFR261.3(cHd)).
B. Existing Extraction Procedure
Toxfcity Characteristic
The Extraction Procedure (EP) toxicity
characteristic is one of four existing
hazardous waste characteristics (along
with ignitability, corrosivity, and
reactivity) that EPA has identified and
promulgated (40 CFR 261.24). The
Extraction Procedure Toxicity
Characteristic (EPTC) defines the
toxicity of a waste by measuring the
potential for the toxic constituents in the
waste not subject to subtitle C controls
to leach out and contaminate ground
water at levels of health or
environmental concern. To determine if
a waste exhibits the EPTC, constituents
are extracted in a procedure that
simulates the leaching action that occurs
in municipal landfills. Because a
"hazardous waste" is defined as a waste
that may pose~a substantial hazard
"when mismanaged," the EP was
designed based on the assumption that
wastes not subject" to, subtitle C controls
would be co-disposed with municipal
waste in an actively decomposing
landfill that overlies an aquifer. Thus,
the EP identifies wastes that are likely
to leach hazardous concentrations of
particular toxic constituents to ground
water under conditions of improper
management.
The Agency recognized that not all
wastes are managed according to the'
mismanagement scenario postulated for
the EP. However, it is necessary to make
assumptions about management
practices for unregulated wastes in
order to determine whether a waste
poses a threat to human health and the
environment and thus meets' the
statutory definition of hazardous waste.
In addition, the Agency believed that a
reasonably conservative
mismanagement scenario was .
warranted in light of the statutory
mandate to protect human health and
the environment.
Under the existing EPTC, the liquid
waste extract obtained from the EP is
analyzed to determine whether it
possesses any of 14 toxic contaminants
that were identified in the National
Interim Primary Drinking Water
Standards (NIPDWS): eight metals
(arsenic, barium, cadmium, chromium,
lead, mercury, selenium, and silver), four
insecticides (endrin, lindane,
methoxychlor, and toxaphene), and two
herbicides (2,4-D and 2,4,5-TP).
NIPDWS levels are used as health-
based concentration limits. At the time
of promulgation of the EPTC, the
NIPDWS were ;the only available,
.benchmarks for toxicity that were
scientifically recognized and that also
addressed chronic exposure.
The regulatory levels established for
the EPTC were 100 times the NIPDWS.
The 100-fold factor is a dilution and
attenuation factor (DAF) that estimates
the dilution and attenuation of the toxic
constituents in a waste as they travel
through the subsurface from the point of
leachate generation (i.e., the landfill) to
the point of human or environmental
exposure (i.e., at a drinking-water well).
The Agency had originally proposed a
DAF of 10 for use hi the EP. In light of
the fact that there were few empirical
data on which to base the DAF and
other considerations, the Agency
adopted a DAF of 100 in the final rule
(45 FR 33084^ May 19,1980). EPA was
confident that any waste which
exhibited the EPTC using the 100-fold
factor would have the potential to
present a substantial hazard regardless
of the actual site-specific attenuation '
mechanisms. The Agency also noted
that it would adjust the DAF if future
studies indicated that another DAF was
more appropriate.
C. The Hazardous and Solid Waste
Amendments of 1984
On November 8,1984, the Hazardous
and Solid Waste Amendments of 1984
(HSWA) were enacted: these
amendments have had far-reaching
ramifications fo;r EPA's hazardous waste
regulatory program. RCRA sections 3001
(g) and (h), which were among the many
provisions added by HSWA, direct EPA
to examine and revise the EP Toxicity
Characteristic and to identify additional
hazardous waste characteristics,
including measures of toxicity. Today's
rule fulfills these mandates by
promulgating am improved leaching
procedure that better predicts leaching
and an expansion of the Toxicity
Characteristics (TC) list to include
additional toxicants.
RCRA section 3001(g) specifically
directs EPA to examine the EP leach
procedure as a predictor of the leaching
potential of waste arid to make changes
necessary to ensure that it accurately
predicts the leaching potential of wastes
that may pose a threat to human health
and the environment when mismanaged.
The legislative history for this provision
indicates that Congress was specifically
concerned about the EP's ability to
accurately represent the mobility of
toxicants under a wide variety of
conditions. The legislative history also
suggests that Congress intended for EPA
to develop a moire aggressive leaching
medium for the test and noted that me
EP only evaluated the mobility of
elemental toxicants and not the mobility
of organic toxicants.
Concerned that some wastes posing a
threat to human health and the
environment were not being brought into
the hazardous waste system, Congress
adopted RCRA section 3001(h), which
directs EPA to promulgate additional
characteristics. Of specific concern to
Congress was title fact that the existing
characteristics did not identify wastes
that were hazardous due to toxic levels
of organic constituents. Although
Congress recognized that the
development of such a characteristic
would entail technical problems,
Congress urged the Agency to make
reasonable assumptions for purposes of
regulation, rather than await definitive
technical answers. In response to the
3001(g) and 300:l(h) mandates, EPA
issued a proposed rule to revise and
expand the TC [51 FR 21648, June 13,
1986) which isr discussed below in
Section H.D.
D. Previous Federal Register Notices
As indicated above, EPA published a
Federal Register notice (June 13,1986)
proposing to expand the existing TC.
The proposal specifically identified 52
compounds that could cause a waste to
be hazardpus via toxicity, including th3
existing 14 EPTC compounds and 38
additional organic compounds. In
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Federal Register / •Vol. 55, No, 6t / Thursday, Marfch 29i'1990 / Rules and Regulatiohs 11801
addition, it described the Toxicity
Characteristic Leaching Procedure
(TCLP), a new version of the EP. The
TCLP is designed to more accurately
address the leaching of organic
' compounds and to improve upon
technical aspects of the testing protocol
. The June. 13 proposal used a
subsurface fate and transport, model to
determine compound-specific dilution
and attenuation factors (DAFs) as a
basis for establishing the regulatory
levels. (As mentioned above, the
existing TC used a generic DAF of 100
which was not derived from modeling,
.but rather was an-estimated factor
indicating the potential for substantial
hazard.) The extract from the second-
generation extraction procedure, the
. TCLP, was analyzed for the presence of
the 52 constituents at the proposed
regulatory levels. In choosing the 38 new
toxicants, the Agency identified those
Appendix VIII constituents for which
appropriate chronic toxicity reference
levels were available and for which
there existed adequate fate'and
transport data to establish a compound-
specific DAF. (Appendix;VIII of 40 CFR
part 261 is the list of hazardous
constituents that the Agency considers.
in evaluating the potential hazard posed
by wastes; these constituents have been
shown to have toxic, carcinogenic,
mutagenic, or teratogenic effects.)
Chronic toxicity reference levels are
those levels below which chronic
exposure for individual toxicants in
drinking water is considered safe or
considered to pose minimal risk (in the
case of carcinogens). The Agency
decided to use, when possible, human
health criteria and standards that have
been proposed or promulgated for
substances in particular media, because
these have already received Agency.and
public review and evaluation. EPA
proposed the continued use of the
Drinking Water Standards (DWS) for
the 14 existing EP toxicants and use of
Recommended Maximum Contaminant
Levels (RMCLs) for eight of the
constituents being added to the TC list.
"For the remaining newly added
constituents, EPA proposed to establish
chronic toxicity reference levels using
Reference Doses (RfDs) for non-
carcinogens and Risk-Specific Doses
(RSDs) for carcinogens.
The RfD is an estimate of the daily
dose of a substance that will result in no
adverse effect even after a lifetime of
exposure to the substance at that dose.
In order to account for toxicant
exposure from sources other than water
(i.e., air and food), the Agency proposed
to apportion the RfD based on
proportionate compound-specific
exposure routes, as is done in
developing drinking water standards.
The RSD is the daily dose of a
carcinogen over a lifetime that will
•result in an incidence of cancer equal to'
a specific risk level. EPA proposed a
w.eight-of-evidence approach, which
involves categorizing carcinogens
according to the quality and adequacy
of the supporting lexicological studies,
to establish the risk levels most
appropriate for setting chronic toxicity
reference levels for carcinogens.
The Agency proposed using a
subsurface fate and transport model to
calculate constituent-specific DAFs.
This model incorporated compound-
specific hydrolysis and soil adsorption
data, coupled with parameters
describing an underground environment
(e.g., ground water flow rate, soil
porosity, ground water pH). Values for
parameters were selected based on
review of geological conditions at
existing landfills. Since the model was
specifically developed to simulate
transport of organics and a model for
inorganics could not be completed in
time for the June 13 proposal, EPA
proposed to retain the existing EP levels
for the eight inorganic toxicants.
The proposed rule introduced the
TCLP as a second-generation leaching
procedure to replace the existing EP.
The main impetus behind the
development of the TCLP.was the need
to address the leaching of organic
compounds. However, the Agency alsa
recognized that the EP protocol could be
improved in certain ways. The TCLP
was described in detail as a proposed
revision to Appendix II of part 261.
Further supporting information on the
TCLP was provided through notices of
availability of reports on July 9,1986 (51
FR 24856) and September 19,1986 (51 FR
33297). After the TC proposal, the Land
Disposal Restrictions final rule (51 FR
40572, November 7,1986) promulgated
the TCLP for monitoring compliance
with treatment standards for certain
spent solvent wastes and dioxin-
contaminated wastes. See Section II.E
below'for further discussion of these
notices.
E. Other Notices Relating to the
Proposal
Today's rule is based on three
fundamental analytic components that
were set forth in the original June 13
proposal: a set of chronic toxicity
reference levels, a subsurface fate and
transport model, and the TCLP. In
addition to the June 13,1986 proposed
rule described in the preceding section
of this preamble, EPA has published .
several other notices in the Federal
Register dealing with these three
components. These notices are listed in
Table II.l and are summarized in this
section. A more detailed discussion is
presented on several of these notices in
other sections of this preamble, as
identified in Table II.l.
TABLE IL1—RELATED FEDERAL REGISTER NOTICES DISCUSSING ONE OR MORE OF THE ANALYTICAL COMPONENTS OF THE REVISED
TC
Jan. 14, 1986, 51 FR 1602 (Proposed LDR framework)
Nov. 7, 1986, 51 FR 40572 (Final LDR approach) '.
May 18, 1987, 52 FR 18583 (Consideration of separate wastewater TC)
May 19, 1988, 53 FR 18024 (CTRLs updated, two-tiered DAF alternative
proposed). - .
May 24, 1988, 53 FR 18792 (Proposal to replace particle reduction).
Aug. 1, 1968, 53 FR 28892 (Proposed modifications to ground water'
model).
CTRLs r
X
Analytic Component
Model *
X
X
X
X
TCLP 3
X
X
X
X
Relevant preamble
section of today's rule
III.E, lll.l
III.F
III.A, III.H
III.C, III.D
III.F
III.E
1 Chronic Toxicity Reference Levels.
2 Ground water fate and transport model.
0 Toxicity Characteristic Leaching Procedure.
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11802 Federal Register / VoL 55. No. 61 / Thursday. March, 29. 1990 / Rules and Regulations
EPA's first discussion of the
development of regulatory levels
through the use of chronic toxicity
reference levels in combination with a
subsurface fate and transport model
was in the proposed rule governing land
disposal restrictions for solvents and
dioxins (51 PR 1602, January 14,1986}:
This proposal introduced the concept
involved in "back-calculating"
regulatory levels (i-a, multiplying
chronic toxicity reference levels by
dilution/ attenuation factors) and also
discussed the Agency's plan for revising
the EP. In the final: rule on land disposal
restrictions for solvents and dioxins (51
FR 40572, November 7,1988), EPA
decided not to use the "back-calculation
approach" for the LBR program in favor
of an engineering determination based
on the best demonstrated, available
technology (BOAT). However, the
Agency did promulgate the revised
TCLP as the leaching procedure to be
used in the land disposal restrictions
program. Specifically, the TCLP is used
to demonstrate that certain wastes meet
the best demonstrated available
technology standards.
On May 18,1987, EPA published a
Supplemental Notice of Proposed
Rulemaldng (52 FR 18583} in response to
numerous comments on the June 1986
proposal concerning the application of
the revised TC to wastewaters. The
commenters* main concern was that it
may be inappropriate to apply the TC
mismanagement scenario (co-disposal of
wastes with municipal wastes in an
unlined landfill) to wastewaters
managed in surface impoundments. The
commenters believe that such an
approach would result in
inappropriately low regulatory levels.
The Supplemental Notice outlined
several alternatives for the application
of the TC to wastewaters that would
result in a separate set of regulatory
levels for these wastes. The alternative
scenario for wastewaters assumed that
subject wastes are managed in an
unlined impoundment instead of being
co-disposed in a municipal landfill.
Sections HLA.2, m.E., and ffl.H provide
further discussion of the Supplemental
Notice for wastewaters and related
issues.
The Agency then published a Notice
of Data Availability and Request for
Comments on May 19,1988 (53 FR
18024), as a result of its concern about
uncertainties and technical difficulties
involved,with developing sufficiently
representative dilution/attenuation
factors (DAFs) for specific constituents.
In that notice, the Agency proposed an
alternative to the constituent-specific
DAFs in the proposed TC. The Agency
presented a two-phased approach to
implementing DAFs for the TC. In the
first phase, the Agency would use
generic. DAFs for all, 38 new TC organic
constituents-while the development of
constituent-specific DAFs proceeded; •
once the.de velopment of the constituent--
specific DAFs was completed, these
DAFs would be implemented in the
second phase. The Agency specifically
requested comment on the use, of a
generic DAF that would initially bring
into the hazardous waste regulatory
system the most toxic of the wastes
subject to the June 1988 proposal. The
Agency also updated the chronic
toxicity reference levels for a number of
constituents based on newly available
information. Section ULC discusses the
incorporation of the new information
into the chronic, toxicity reference levels
for specific constituents and Section
III.D describes in more detail the twa-
tiered DAF approach.
In response to numerous comments
expressing concern as to whether the
particle reduction requirement in the
TCLP was appropriate, EPA published a
proposal (53 FR 18792. May 24.1988)
requesting comment on, modifications to
the TCLP as promulgated on November
7,1986. Based on further experimental
evaluation of the original testing
methodology, the Agency proposed to
modify the TCLP to include a cage insert
requirement in place of the particle
reduction step for certain materials. The
specific revisions discussed in the
proposal are presented in detail in
section ffl.F of this preamble, and the
TCLP protocol is presented in Section
VIII of today's final rule. Today's rule
does not include a cage requirement, but
rather retains the. particle reduction step
for monolithic or fixated wastes.
In addition to the above-mentioned
modifications, on August 1; 1988, the
Agency published a Supplemental
Notice (53 FR 28892] introducing
potential modifications to the
subsurface fate and transport model
used to calculate constituent-specific
DAFs in the proposed TC. In addition,
the Agency presented currently
available hydrogeological data on
municipal waste landfills and proposed
to modify the subsurface fate and
transport model to more accurately
reflect conditions in the universe of
municipal waste landfills. Section IILE
presents a more detailed description of
the subsurface fate and transport model
and the modifications made during its
development.
F. Pollution Prevention
In section 1003(b) of RCRA, Congress
declared waste minimization to be a
national policy. Similarly, EPA has
made.poUution.iireven.tion an Agency
objective, in botii regulatory and
'., nonregula'tary programs, (See EPA's
policy statement emphasizing the.
importance of pollution prevention (54
FR 3845, January 28,1989).) This policy
places highest priority on source
reduction (i.e.. reducing the volume or
toxicity of wastes generated} and use of
all pollutants for1 all sectors of society. A
reduction in the .amount of waste which
must be managed (i&» by source
reduction and recycling} provides direct
benefits related to •protecting human
health and the environment from the
mismanagement of hazardous wastes.
Pollution prevention measures can also
reduce waste treatment and disposal
costs, decrease costs for raw materials,
minimize liability and regolatory
burdens for waste generators, and may
enhance efficiency, product quality, end
public image. The Agency encourages
industries affected by tbia role to
consider achieving compliance through
pollution prevention.
The Agency has taken several steps to
create pollution prevention incentives.
First, EPA is developing institutional
structures within each of its offices to
ensure that the ppollution prevention
philosophy; is inexwporated into every
feasible aspect cif internal EPA planning
and decision-making. Second, EPA is
making technical information available
to help firms reduce waste generation.
EPA is developing the Pollution
Prevention Information Clearinghouse
(PPIC), a network of people and
resources throughout the United States
that have direct experience in many
industries. PPIC includes the Electronic
Information Exchange System (EIES),
and a database of bulletins, programs,
contacts, and reports related to pollution
prevention. Third, the Agency is
supporting the development of state
programs to assist generators in their
waste reduction efforts. Many states are
already providing such help. For
example, the Alaska Health Project has
published technical assistance packets
for specific ihduutries; North Carolina
has a pollution prevention bibliography;
and Oregon conducts a hazardous waste
reduction program. Finally, EPA has
initiated specific regulatory
requirements addressing waste
minimizatioii. Under the Resource
Conservation and Recovery Act (RCRA)
regulations,, hazardous waste generators
are required to certify on their
hazardous waste manifests, and annual
permit reports that they have a program
in place to reduce the volume or
quantity and'toxicity of their .hazardous
wastes as much as economically
practical. RCRA regulations also require
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Fedetel Register / Vpt''&%(No. 6'l / Thursday; March 29, 1996 •): Rules and kegiilktions 11803
generators to describe on their RCRA
biennial reports the efforts they have
undertaken during the year to reduce the
volume and toxicity of their hazardous
waste and to compare these efforts to
previous years.
As important as the efforts just
described is the Agency's commitment
to ensuring that regulations under
development encourage pollution
prevention, whenever possible. The TC
(TC), we believe, provides significant
incentives for pollution prevention. .
Currently, there is little incentive for
industries to implement pollution
prevention efforts for unregulated solid
wastes. In particular, there are few
controls on units handling solid wastes
that have the potential for releases of
hazardous constituents to groundwater.
Large quantities of solid wastes
containing TC constituents currently are
managed in unregulated land-based
units, such as surface impoundments
arid landfills. Many of these units are.iri
states that are either highly dependent
on groundwater for public Water supply
or where groundwater is hydraulically
connected to surface water; or both. By
subjecting management of TC wastes to
subtitle C regulation, EPA is. in effect
requiring that waste managers rethink
their practices for solid wastes that.
contain hazardous constituents. EPA's
experience has been that hazardous
waste regulations provide significant
incentives for pollution prevention. For
example, some listed wastestreams (e.g.,
bottoms from tetrachloroethylene
production) are now completely '
recycled.
The characteristic mechanism'used by
EPA to identify hazardous waste is
especially effective in encouraging
pollution prevention because it sets a
concentration level or criteria (e.g. test)
that determines the point at which the
waste is no longer regulated as
characteristically hazardous. Because of
the high cost of compliance with RCRA
subtitle C requirements, members of the
regulated community will have
significant new incentives to reduce TC
waste generation as a result of today's
rule. Industries will consider substitutes
for the specific chemicals on the TC list
of toxicants of concern. Where
substitutes are not used, there will be
incentive to reduce the use. of hazardous
substances or otherwise limit their
concentrations in wastes, in order to
keep concentrations of hazardous
chemicals below regulatory levels.
Pollution prevention options range
from simple good housekeeping
practices, e.g., keeping solvents and oils
separate to facilitate recycling of each,
to more extensive process
reconfigurations and/or raw material
substitutions. Even in cases where
pollution prevention can not eliminate
the need for treatment or disposal of
hazardous wastes, it may reduce the
generation of waste. For example, tank
capacity is constrained by land area,
engineering considerations, and cost.
Managers of TC wastewaters that
switch from surface impoundments to
exempt tanks will almost certainly have
to reduce volumes of hazardous waste
generated, or segregate hazardous
portions of their wastestreams.
In order to enhance the pollution
preventions effects of this rule, EPA is
incorporating pollution prevention into
the communication strategy for the TC
regulation. EPA will provide information
targeted to small businesses specifically
arid industry in general through
pamphlets, industry publications and
conferences, on the mechanisms
described above. We have found that
many small businesses are turning to
pollution prevention as a result pf
implementation of the small quantity
generator regulations (see 51FR10146,
March 24,1986). For example, PPIC
documents relate how one drycleaning
operation reduced its solvent wastes tb
a level well below national industry
standards by regularly checking for and
sealing any system leaks, and installing
a conditioning system and a carbon
adsorptipn unit to recover additional
solvent. With the new setup, the plant
can clean four times as many clothes per
drum of solvent. The Agency believes
that other industries may have the
potential to substitute less toxic source
materials in their processes. EPA will
consider whether any technical
assistance could aid industry in these
efforts. EPA would also be interested in
suggestions from industries affected by
the TC in ways that the Agency might .
facilitate these efforts. Inquiries should
be directed to the Pollution Prevention ;
Office, U.S. EPA, Washington, DC 20460.
In summary, the TC will alter the
management of wastes that contain
toxicant at hazardous levels by ending
management in unregulated land-based
units. As industries reassess their waste
generation and management practices,
many are likely to seriously .consider.
pollution prevention options, arid EPA
will take steps to facilitate such efforts.
G. Summary of Final Rule
Today's rule retains many of the '
features of the June 1986 proposal: it
replaces the EP with the TCLP; it adds '
25 new organic constituents to the list of
toxic constituents of concern; and it
establishes regulatory levels for the,
organic constituents based on health-
based concentration limits arid a DAF
developed using the Subsurface fate and
transport model. In response to
comments received on the proposed rule
. and related notices, the final rule
incorporates a number of modifications
to the list of constituents, the leaching
procedure, the chronic toxicity reference
levels, the subsurface fate and transport
model, and the schedule for compliance
with the TC rule.
With respect to the list of
constituents, the final rule includes 25 of
the 38 constituents proposed in 1988.
One group that has been excluded in the
final rule are constituents that
appreciably hydrolyze. EPA has been
able to develop scientifically valid DAFs
for.nondegrading constituents but is still
improving its approach for developing
DAFs for constituents that are expected
to hydrolyze appreciably during
transport. In particular, the Agency does
not yet have a procedure to address
toxic hydrolysis byproducts that may be
formed.
Second, in response to comments, the
Agency has also evaluated the,
applicability of the steady-state
condition assumed in the subsurface
fate and transport model, and has
determined that the assumption is valid
for most of, the originally proposed
constituents. However, several of the
original proposed constituents have
been deferred from the final rule while
the Agency continues to evaluate the
extent to which the steady-state solution
is appropriate in determining their fate
and transport.
As a result, all the constituents newly
regulated under today's rule are ,
nonhydrolyzing or minimally •
hydrolyzing constituents, and all are
constituents for which the steady-state
solution is appropriate. For all these
constituents, EPA has determined,
based on the results of its subsurface
fate and transport model, that use of a
DAF of 100 is appropriate for setting
regulatory levels. This DAF is sufficient
to capture only those wastes that are
clearly hazardous. As a result of the
Agency's decision to regulate only
nonhydrolyzing or minimally
hydrolyzing constituents and those for
which the steady-state solution is
appropriate, 25 additional constituents
are being regulated rather than the
originally proposed 38. Regulatory levels
for hydrolyzing constituents, as well as
those constituents for which there
remain questions as to whether the
steady-state solution is appropriate, will
be discussed in future notices.
The list of constituents regulated in
today's rule and their respective
regulatory levels are presented in Table
II.2. As in the proposed rule, where the
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11804 Federal Register / Vol. 55, No. 61 / Thursday, March 29, 1990-f Rules -and
calculated regulatory level (i.e., the
chronic toxicity reference level
multiplied by the DAP) is below the
analytical quantisation limit, the
quantitation limit is the final regulatory
level. Note that the list of constituents in
Table n.2 contains the 14 constituents
currently regulated under the existing
EPTC. As specified in today's rule, these
constituents will continue to be
regulated at their current levels.
TABLE 11^.—TOXICITY CHARACTERISTIC CONSTITUENTS AND REGULATORY LEVELS
EPAHWNo.1
DOM
0005
D018
0006
0019
0020
0021
0022
D007
0023
D024
0025
0026
0016
0027
D028
DO 29
0030
0012
0031
D032
0033
0034
0006
0013
D009
D014
D035
D036
D037
0036.
0010
001 1
0015
O040
O041
0042
0017
0043
• Constituent (mg/L)
BflfftBTl H>tn»u*» »»«•»*»•»••»•*••••- ••**•»*** «...-.,..«.«..*.««.....».«..»..—«-««.««.«
Ctdmium . t ,„ , -,rtt , '-
ChJofdane . » . ».»«..««««.«...
Chkvobsnz&na
CtrtofOfOfiT>............ »...«.»...«......»»... »««»..«.«.
ChrofTxiiTt «*»•..••• ».•».« « *»•.» «..
frCre** ., ~ -,.~ —
D-Cro9of
Cresol.
?4-T*
1J2-DtchkjfOOthano. __........_._._...... - _..„....„„.._....__.___.__
|«J^okKm<»._.. _ ™. ~~
KepUictUoc (and Its hydroxide) ._,.......... ..„..._.. „ ~
lff*rt
I hyjfji^ •
Mwcitry
MetficxYeWor
Kttt.yl Bthy< fceJono. „ „ ._ .
Pvritffew •
Selenium
Gtoar
TA^ Kli-tfn^lfi rf^n
ToxaSena11' ! "*" " " ""'"
TrfchJofoathytene ~ •
2,4,5-Tricfitofophonol..... _* .__ _
?H,5-TP (Sivrn) . • •
-
CAS No.1
7440-38-2
7440-39-3
71-43-2
7440-43-9
56-23-5
. 57-74-9.
108-90-7
67-66-3
7440-47-^3
95-48-7
; 108-39-4
106-44-5
94-75-7
106-46-7
107-06-2
75-35-4
121-14-2
72-20-8
76-44-8
118-74-t
87-68^3
67-72-1
7439-92-1
58-89-9
7439-97-6
72-43-5
78-93-3
98-95-3
87-86-5
110-86-1
7782-49 2
7440-22-4
1 P7-1 R-4
8001-35-2
79-01-6
95-95-4
88-06-2
93-72-1
75-01-4
Chronic tarfcity refecence
level (mg/L)
0.05
1.0
0.005
0.0t
0.005
0.0003
1
0.06
0.05
2
'2
2
2
O.1
0.075
0.005
0.007
0.0005
: 0.000?
0.00008
! 0.0002
0,005
0.03
0.05
0.004
O.002
0.1
2
0.02
t
0.04
0.01
0.05
0007
0.005
(J.005
4
0.02
0.01
Q.OQ2
ao
100.0
0.5
1.0
0.5
0.03
1000)
6.0
5.0
* 200.0
*200.0
« 200.0
•200.0
10.O
03
'aol
0.008
0.5
3.0
5.0
tt4
0.2
10.0
200.0
2.0
ioao
'5.0
tjO
1 5.0
• O7
&5
QJ5
400.0
2.0
T.O
0.2
t Hftc&idous wfisld nufnber. • , , '
* Chmtcai fti)ftt£ict& soivlo number. • '
* Qunr.tiU'ica fcnct Is. Qreelcf than the calculated regulatory, teveh The quantitation ItmS tnerefore becomes the regutetaj tevefc. .
« H 0-. nv, and p-owot concentrations cannot be differsntfated; *» iota cresot (DO26J eoncentraSon fe used. Tha regulatoiv laval for total cresol is 200 mg/l.
The rcgulatoiy levels reQect
modifications to some chronic toxicity
reference level* since the original
proposal EPA has revised some of the
Maximum Contaminant Levels, Risk-
Specific Doses, and Reference Doses to
reflect new data and better methods, m
response to comments received, EPA
has decided not to apportion reference
doses of noncarcmogens to account for
multiple routes of exposure, as was
originally proposed [51FR 21648). See
section m.C for further discussion of
comments on apportionment and the
Agency's reasons for not including
apportionment of reference doses, in the
final rule. Today's rule also promulgates
the TCLP to replace the EP. The TCLP
represent* «n improvement over theEP ,
In that it more accurately addresses
leaching potential for use in evaluating
wastes containing organic constituents,
and also corrects several minor ,
technical deficiencies in the original EP.
TheversioEofihsTCLPproHiulgated
today reflects additional improvements
and njodificatics* made to the TCLP
since the original proposal. The TCLP
promulgated today wffljpteo replace the
earlier version of the TCLP promulgated
as part of 'the land disposal restriction?
program.
Today's rule incorporates a schedule
for compliance that classifies the
universe of potentially/ affected TC .
waste handlers into two groups: £1} All
generators of greater, titan, too kg/month
and less than TgOOO kg/moala 61
generators) mast came into compJiaace
with the subtitle C requirements for
management of their TC waste within t
year; and (2J aHgenerators of 1,000kg/
month or more ol hazardous waste 'are
required to comply with all subtitle C
requirements for TC wastes within 6
months. The phased schedule for
compliance is further discussed in
sectionV.
Wastes identified as hazardous under
the Toxicity Characteristic will also
become hazardous substances under
section 101(14) of the Comprehensive
Environmental B,esponaet
Compensation; soad Liability Act of I960
(CERCLA), as sisanded. Today's rule
amends the list «f sepoitebte quaatities
(RQs] in 40.CFE part 3C2 by adding
appropriate values fct.each of the new
25 TC toxicants. All of th® newly-
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Federal Register / VoL 55, No. 61 / Thursday, March 28, 1S90 / Rides and Regulations HUBS
designated TC toxicants ate already
listed as CERCLA hazardous
substances. The RQs being promiiigated
are the same as those that already apply
to all materials contaiaing these
hazardous substances.
Today's rule defers applicability of
the TC to one type of waste and
exempts another. First, the Agency I*
deferring the applicability of the TC to
. petroleum-contaminated media and
debris al sites subject to the RCRA
Under^tound Storage Taak fUSTJ
cleanup regulations under part ,280. {See
section HII.fi.] Second, EPA has decided
to exempt from today's rule certain
polychlorinated biphenyl JPGB] wastes
that are Fully legulated under the Toxic
Substances and Control Act fTSCAj and
would be identified as hazardous
because of today's rale JSee section
IILJ.7.J.
In portions of the existing codified
waste regulation of title 40, chapter J,
parts 261 through 265, file EPTC is
named. Today's action of promulgating
the TC necessitates amendment of these
references to fee EPTG. This amendment
which replaces references to fee T3PTC .
with the words "Toxtcaty
Characteristic" applies to the following
sections of 40 CFR: 281.403M8Mfl not
265.221td]Il} and 265.273{a3.
In I § 2M.301feM:i3 and 285.221(dHl3. to
addition to amending reference to She
EPTC, the universe of constituents
remains the same as the EPTC. To.
aceompllslrthis, Sic constituents DB84-
DQ17, the E^TC constituents, are
specifically named as those constituents
which would not render the waste
hazardous by the f C.
As discussed below, the Agency will
continue to refine the "1C m order to
pnwide greater accuracy and
comprehensiveness in identifying
hazardous waste based on the waste's
toxic constituents. However, the Agency
believes that today's tote fulfills the
statutory mandates ander sections
3001(g}and30Ga{h}.
III. Response to Major Comments and
Analysis ®f Issues
The Agency neceived isaany commenta
on die jfune 13, 1988 proposed rails and to
response to subsequent notice*. The
Agency has carefully considered ail
comments in the preparation of this final
rule, To facilitate the .evaluation and
response to comments, the Agency
grouped the comments into tea
categories. The categories are as
follows;
A. General Approach
B. Constituents of Concern
C. Chronic Toxicity Reference Levels
D, Use of Gesfifie DAFs
E.Applscafeniof a Subsurface Faie and
Transport Model
F.TheTCLP
G. Testing and Recardkeeping
.Requirements
H. Applicability to Wastes Managed la
Surface Impoundments
I. Relationship to Other RCRA
Regulations '
}. Relatkraslup to Other Regulatory
Authorities
In this preamble, the Agency provides
summaries of and responses to major
comments. Readers are invited to refer
to background documents {Kefs, t, £, 3,
and 4) for complete summaries and
responses to all comments.
A. Gemfml ApprQ&dh
\. Expanded Use of Hazardous Waste
Characteristics.
T&e TC revisions specified in todays
rule refine and expand She EPTC, Most
commeaters stated that increased
reliance on jxszardoas waste
characteristics is a reasonable approach
to defining hazardous waste. Some
comraeniers stated a jweferenoe for the
hazardous waste characteristic
mechanism oyer tije alternaiive listing
mechanism for identifying isaaardous
wastes. They noted that tbe
characteristics are designed to
directly the risks thai subtitle C
Tegulations axe meant to control
of the TC. RC8A secticai 3COi{hJ states
"* * * the Administrator shall
wa
A few coaime-nters, hnwesET, ofef&cled
to the expanded use of feazardoas waste
characteristics. Same of iiiese
commeaters qnsstioaed fee Agency's
authority ta develop the TC. One
commenter asserted that RCRA section
3001(h] dees not authorize EPA to take
the action of adding the proposed
organic constitsienis to the list of TC
constituents. Another argued that Use
legislative Justory of HSWA indicates
that changes in the leaching pnocedajire
should address the leaching of toxic
metals only. This coHimEjatsr claimed
that fee Agency had exceeded its
statutory mandate by aasdiiymg the TC
to include orgaancs.
commenters who argued that the
Agency lacks authority to expand tfee
TC. The Agency's appnsadi to
identifying hazandc-iia wastes throisgJs a
preceduse was well established in 1S84,
when Congress passed HSWA. HSWA
not only confirmed ihs vaiidiiy of EPA's
approach to id«ntifyiog hazardous
wastes by characteristics, but aJso
diifflctsd tise Agency to expand the scope
section identifying additional
including measures or indicators of
toxicity." Thais, the plain language of the
statute aTathorizes EPA to broaden the
TC. .
EPA's authority to expand the TC, bat
offered policy arguments against IJhe use
of this mechanism for identifying
hazardous wastes. Most ccunmenters
who argued against expanded «se of
characteristics favored use of the listing
mechanism instead of an expanded TC.
Some of these commenters noted feat
listings do not present the same
technical problems of precision and
accuracy as $he characteristics. Others
stated that listings we more easily
enforced since they are not dependent
upon use of a leaching procedure.
Finally, some commenters claimed'thal
by expanding flte toxicity characteristic
instead of listing additional wastes, EPA
is unfaMy sniffing the burden for
identifying hazardous wastes onto the
shoulders of the regulated community.
The Agency maintains that te
' expanded use of characteristics, in
addition to being consistent with the
statutory mandate, offers advantages
over listing for identifying broad
categories of clearly hazardous waste.
Establishing a characteristic allows the
Agency to identify through one rule
those wastes which are reasonably
certain to pose a threat to human health
and fhe environment by virtue of an
inherent characteristic without
expending vast Federal resources to
study, characterize, and list numeroMS
individual xvastestreams. Since the
Agency sets regulatory levels high
enough to assure that wastes exhibiting
the characteristic are hazardous, the
characteristic approach does not bring
wastes into the subtitle C system which
do not present a substantial present cr
potential hazard to human health and
the envirosmaefl't By contrast, a listiag,
since it applies to all wastes that raa-st a
listing description, may capture some
individual svastestreams thai do not
actually pose a threat to human health
and the environment Generators may
petition for delis ting if this occurs;
however, fee delisting process can be
burdensome to the petitioner and 4o
EPA.
The Agency believes that the
characteristic approach has the
following advantages. First, it is less
burdens-sine for 4i« regulated
commuaaity because the characteristic
approach limits a^sr-inclasiveness,
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11806 Federal Register / Vol. 55, No.61 I!Tiuraday,March 29, 1990 / Rules and Regulations
Second, reducing the potential of
including wastes that do not, in fact,,
present a threat conserves hazardous
waste management capacity and
Agency administrative and enforcement
resources for waste management
activities that warrant priority attention.
Finally, if necessary, a characteristic
can be adapted quickly to possible
future changes in science or technology,
such as lower quahtitation limits.
EPA acknowledges that there are also
some advantages in tising the listing
mechanism for identifying hazardous
wastes, particularly with respect to ease
of implementation; the Agency thus will
retain the listing approach as an
alternative mechanism for identifying
hazardous wastes. The Agency
continues to believe that both the
characteristic and listing approaches are
valid and useful tools in identifying
hazardous wastes that are subject to*
subtitle C regulation.
Finally, the Agency disagrees with
commenters who contend that
characteristics impose an unfair burden
on the regulated community. Since the
establishment of the hazardous waste
identification framework in 1980, EPA
has recognized that the primary
responsibility for determining whether
wastes exhibit hazardous waste
characteristics rests with generators. In
accordance with this, one of two criteria
for establishing new characteristics is
that they must be measurable by ,
standardized and available testing
protocols or reasonably detected by
generators through their knowledge of
the waste (see 40 CFR 281.10). Further,
the regulations do not require testing; a
generator may apply knowledge of the
waste to determine if it is hazardous (40
CFR 282.11).
2. Mismanagement Scenario
Hazardous waste characteristics are
designed to identify solid wastes that
pose a threat to human health and the
environment when improperly managed
(RCRA section 1004(5)). Therefore, in
developing the TC, EPA's first task was
to determine how wastes might
plausibly be mismanaged. The
mismanagement scenario that both was
reasonably realistic and presented the
greatest environmental risks could then
be chosen as the reasonable worst-case
scenario and used as the basis for the
revised characteristic. Specifically, the
characteristic would be designed to
identify any wastes from which toxic
constituents would be likely to pose a
threat to human health and the
environment when managed in
accordance with the selected scenario.
In this way, EPA ensured that wastes
would be adequately controlled,
regardless of the manner hi which they
are actually managed.
In the June 13,1988 proposal, EPA
considered several alternative
mismanagement scenarios for use in the
development of the TC rule,. including
segregated management, co-disposal
with municipal solid waste (the
mismanagement scenario evaluated in
the existing Toxicity Characteristic), co-
disposal with industrial waste in a
landfill subject to subtitle D
requirements, and co-disposal with
industrial waste in a landfill subject to
subtitle C requirements that suffers
some form of containment-system
failure. The Agency rejected the subtitle
C scenario as unrealistic because it is
unlikely that waste generators would
dispose of their wastes in the more
expensive subtitle C landfills unless
required to do so. Thus, it would not be
a realistic scenario.
EPA determined that each of-the
remaining options was a plausible
'mismanagement scenario since most
wastes are or may be managed in these
types of land disposal facilities. The
Agency rejected the segregated
management or "mononll" scenario on
the grounds that it did not represent a •
realistic worst-case practice. Facilities
dedicated to the management of only
one waste Or the wastes 'of only one .
generator (i.e., a "monofill") are likely to
' pose less of a hazard than general
municipal or industrial landfills because
the design and operation problems for a
monofill are simpler and the operators
generally have considerably more
information on the properties of the
wastes that are managed. Also,
industrial monofills generally do not
, generate organic acids that result in an
aggressive leaching medium, as is the
case for municipal landfills. Thus,
industrial monofills pose less of a
potential hazard than municipal solid
waste (MSW) landfills. EPA also
rejected the general (as opposed to
"monofill") industrial landfill scenario
on similar grounds (i.e., the generated
leaching medium may not, in some
cases, be as aggressive as in a municipal
landfill). The Agency therefore retained
the municipal landfill scenario as the
reasonable worst-case mismanagement
scenario for the revised TC.,
a. Extent to Which Scenario is
Reasonable. Several commenters
challenged the municipal landfill
scenario, claiming that it is based on an
unreasonable assumption about the way
in which industrial solid wastes are
managed. These commenters: claimed
that industrial wastes are rarely
disposed in MSW landfills. If landfilled
at'all, these wastes are more likely to be
disposed in industrial landfills, In
addition, industrial wastes are
frequently managed in ways other than
landfill disposal (e.g., Incineration,
recycling, treatment on the land, or
treatment in surface impoundments)*
Thus, commenters argued, it is
inappropriate to base the TC on the
municipal landfill scenario.
EPA fully recognizes'that not all
industrial wastes are managed in MSW.
landfills. Nevertheless, the Agency
continues to believe that the MSW
landfill scenario is reasonable because
such landfills have traditionally
accepted unregulated industrial wastes.
It is for this reason that the MSW
landfill scenario was originally
established, as the basis lor the EPTC
(see 45 FR 33112, May 19,1980),
Although fewer types of industrial
wastes are being disposed in municipal
landfills now as compared to a levy
years ago, EPA'n information confirms
the continued appropriateness of this
scenario. The "State Subtitle D
Regulations on Solid Waste Landfills"
(Ref. 5), and the "National Survey of
Solid Waste (Municipal) Landfill
Facilities" (Ref. 6) indicate that most
states impose few restrictions, if any, on
the types of nonhazardous wastes
accepted at these facilities; moreover, a
substantial quantity of the wastes
received (typically five to eight percent)
are industrial wastes. Thus, EPA
continues to believe that the municipal
solid waste landfill scenario represents
the most appropriate reasonable worst-
. case mismanagement scenario.
Many commenters suggested that EPA
grant exception^ or Variances for wastes
that are not co-disposed with MSW. In
this way, the TC would apply only to ,
those wastes that are actually managed
in accordance with the underlying
mismanagement scenario. The
commenters noted that EPA could
separately develop alternative
characteristics for wastes managed in
other ways to ensure adequate
protection of human health and the
environment.
After; careful consideration, EPA has
decided not to a.dopt this suggestion for
various reasons. Applying the TC only
to wastes actually managed as
suggested in the mismanagement
scenario would involve the creation of a
management-based approach to
identifying hazardous wastes. EPA's
current approach to establishing
characteristics which identify certain
wastes as hazardous is not.contingent
upon the way individual wastes are
actually managed. Rather, consistent
with the RCRA Sectipn 1004(5)
definition of hazardous waste, EPA is
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Federal Register ./ VoL 55. Mo. 81, / tlairsday, March 2S, 1998 /Rules and RJ^gulatioas 13107
identifying waste "'* * * that may pace
a substantial present or potential aasard
to human health and the environment
when Improperly * *
(emphasis added}.
EPA has considered the possibility of
characteristics, i^e.. different
characteristics for categories of waste
depending en how they are typically
managed. However* ifae Agency fcelfewes
that such an approach would present a
number of difficulties. For instance, a
management-based approach to
hazardous waste identification could
substantially complicate effective
implementation of the RGRA
regulations. In particular, it is not
always possible to determine—at the •
point of generation, during transport, or
even as a waste enters a treatment,
storage, or disposal facility—how a
solid waste will ultimately be managed.
EPA believes that the most effective and
appropriate approach is to identify
hazardous waste characteristics, not
according to idle ways in which
individual wastes are managed, but by
identifying properties
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11803 Federal Register /Vol. 55, No. 61 / Thursday, Match 29, 1990 / Rules and Regulations
2. The "physical property-based" approach,
which would apply to. those wastes haying a
certain physical property, indicating that they
ara likely to be managed in surface
Impoundments (e.g., percent solids less than 5
percent]; and
3. Tha "definition-based" approach, which
would apply to those discharged wastewaters
that* are subject to regulation under either
section 402 or section 307(b) of the Clean
Water Act.
Commenters from various industries
generally supported a separate
mismanagement scenario* because they
do-not believe that the landfill
mismanagement scenario is appropriate*
for aqueous wastes managed in surface
impoundments. Most of these
commenters requested that EPA adopt
either the management-based approach
or the definition-based approach.
Other commenters, however, opposed
a separate mismanagement scenario for
wastes managed in surface
impoundments. These,commenters,
contended that the surface
impoundment mismanagement scenario
would not be a reasonable worst-case
scenario, particularly if the scenario
modeled biodegradation, because
significant biodegradation does not
occur in all impoundments. In addition,
the commenters stated that if the
development'of a surface impoundment
mismanagement scenario results in two
sets of regulatory levels, requirements
for storage, handling, and transportation
of a waste would be based on the
management practice that the generator
assumes or expects will actually occur.
These commenters were opposed to this
result and noted that wastes may not
always be ultimately disposed in the
manner originally intended by the
generator.
After receiving these comments', the
Agency decided to revisit the issue of
whether or not a separate
mismanagement scenario is necessary
for surface impoundments due to
inappropriately low regulatory levels.
As described in section HLE.2, the
Agency believes that evaluation of the
physical phenomena that affect dilution/
.attenuation factors (DAFs) indicates
that the DAFs generated for landfills are
similar, if not greater than, DAFs for
surface impoundments (i.e., the
regulatory levels for surface
impoundments would be equal to,or
more stringent than those for landfills).
To confirm this.conclusion, EPA then
investigated whether results from
modeling a surface impoundment.
scenario would in fact be significantly
different from modeling a landfill
scenario. As described later in this
preamble, for nondegrading
constituents, EPA calculated the 85th
and 90th percentile DAFs for landfills
(which ranged from 134 to 47) and the
85th and 90th percentile DAFs for
surface impoundments (which ranged
from 111 to 51). The surface
impoundment results were obtained by,
using the updated model, (EPACML) for
the landfill scenario with leachate
generation and environmental
parameters (e.g., well distances, facility
areas) derived from surface
impoundment data.
As a result of this analysis, EPA is ;.
confident that the results from modeling
of the landfill mismanagement scenario
are also appropriate for wastes
managed in surface impoundments (i.e.,
the DAFs are of the same order of
magnitude). The Agency therefore does
not plan to develop a separate surface
impoundment mismanagement scenario
at this time. Since the modeling results
indicate that the dilution/attenuation
factors for non- and minimally
degrading constituents are all on the
order of 100, the Agency has concluded
that a single value of 100 is an
appropriate choice for use in
establishing the regulatory levels for all
of the constituents addressed in today's
rule. (See section III.E. of this preamble
for an additional explanation of EPA'8
modeling efforts and choice of DAFs.)
3. Targeted Risks
Several commenters argued that, even
if the co-disposal mismanagement
scenario was appropriate, EPA
improperly focused on a few selected
'risks from this scenario. Specifically,
they claimed that the Agency restricted
its consideration to human health risks
resulting from ground water ''
contamination. A number of
commenters stated that the Agency
should consider additional routes of
human exposure, such as air
volatilization, surface runoff, and direct
contact. One cornmenter questioned
why EPA was'not employing the same
multimedia risk and exposure models
that were originally proposed for use in
the land-disposal restrictions program
(see 51FR16Q2, January 14,1986).
A few commenters further suggested'
that EPA take environmental/risks!(e.g.,
. aquatic toxicity) into account, rather
than concentrating exclusively on
human health risks. They noted that
RCRA section 3001(g), on which the TC
rule is based, directs EPA to make
changes in the EPTC so that it
"accurately predicts the leaching
potential of wastes which pose a threat
to human health and the environment
when mismanaged" (emphasis added).
EPA acknowledges that the
characteristic being promulgated today
focuses on human health risks from
ground Water contamination. However,
the Agency does? not believe that a
single characteristic is capable of
identifying all wastes that preserit-a'
threat to human health and the
environment. The present TC revisions
are only the first step in a long-term
strategy to refine and expand the
hazardous waste identification program.
Future characteristics may address
- hazards other than human health risks
resulting from ground water
contamination. EPA continues to
. believe, however,1 that ground water
contamination, ELS a route of human
exposure, is a priority concern.
4. Accuracy
' Several commenters asserted that the
proposed TC revisions failed to fulfill
the statutory mandate to improve the
"accuracy" of the characteristic as a
predictor of the leaching potential of
solid wastes. Specifically; these
commenters argued that, even if EPA
selected the proper mismanagement
scenario, the Agency failed to model the
targeted risks in a reasonable or
appropriate manner. (Many of the ,
commenters addressing this issue also
focused on the accuracy of individual
elements of the characteristic, such as
the TCLP* the subsurface fate and
transport model, or the chronic toxicity
reference levels. These specific concerns
are considered in sections III.B through'
IH.F of today's preamble.)
A number of the commenters on the
issue of accuracy concentrated on the
interrelationship between the various.
element? of the TC. These commenters
pointed out that EPA had employed
conservative assumptions at each step
in the development of the revised
characteristic. They argued that even if
these assumptions were reasonable in
isolation, they would not be reasonable
in combination. According to these .
commenters, the effect of compounding
multiple conservative assumptions
would be a characteristic that is
unreasonably conservative, thereby
resulting in costly overregulation.
•Other commenters maintained.the
. opposite position and stated that EPA
had employed non-conservative
assumptions for many elements of the
characteristic. These commenters
believe that these assumptions result in
a characteristic 'that is not conservative
enough and, thug, not sufficiently
protective of human health and the
environment.
The Agency disagrees with
commenters' assertions that the
elements of the TC are either too
conservative or not conservative
enough. The TC, in particular the fate
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Federal Register ./ Vol. 55, No. &L f Thursday; March:29,
; Rules and ;Reggiatfo|is 118O9
. and transport model used to establish
the dilution/attenuation factors (DAFs),
requires the selection of numerical
values for many parameters. Rather
than selecting values for each parameter
based upon isolated judgments as to
what constitutes a "reasonable worst
case" value, the Agency used the full
range and distribution of values for all
parameters for which such data was
available. By implementing these data
sets through a monte carlo simulation,
the model output (i.e., die frequency
distribution of DAFs) is as realistic as
possible and spans the range of all
possible outcomes rather than
representing only the "best case,"
"reasonable worst-case," etc. That is,
the model output represents all cases,
arrayed-according to their frequency of
occurrence, and does not reflect any
qualitative judgement as to what
constitutes a "reasonable worst ;case".or
any other "case." Accordingly, the
determination as to which DAF value
represents any particular "case" is
solely dependent upon the selection of
the cumulative frequency level. The
Agency's selection of-the cumulative
frequency level is discussed in section
EPA does agree with commenters who
recommended that the originally
proposed subsurface fate and transport
model could be revised to more
realistically represent land disposal .
settings. Accordingly, EPA has modified
the original model (EPASMOD) and has
collected and incorporated new data
into the model. These modifications and
data are described in greater detail
below (section III.E). The reader is
referred to the Response-to-Comments
Background Document for the
Subsurface Fate and Transport Module
(Ref. 1), which presents in detail each of
the technical issues raised by public
comments 'on the model and the
Agency's responses to these issues. EPA
believes that with these changes, the
final TC rule represents a reasonable
approach to the identification of
hazardous wastes.
5. Solvent Override
In the June 13, 1988 TC proposal, the
Agency discussed the possibility of
incorporating a solvent "override"
criterion into the TC because the
presence of large amounts of solvents in
a waste may result in leachate from the
waste mobilizing hazardous constituents
from co-disposed nonhazardous waste.
The Agency considered setting
regulatory levels for solvents based on
the total concentration of solvent found
in the TCLP extract.
Many commenters claimed that
mobilization of toxicants in municipal
landfills by industrial solvents is
improbable. Commenters argued that
there are no data to support the
hypothesis that industrial solvents
would alter the solubility of hazardous
constituents in municipal waste. These
commenters asserted that, at levels
below their solubility in water, organic
solvents exert very little influence on
the solubility of other organics. Given
.the low concentrations of solvent
wastes permitted for land disposal, the
commenters contended that there is
little probability that mobilization will
Occur. Commenters emphasized that, in
general, subtitle D landfills do not
accept organic solvents or liquids. Most
industrial solvents already are listed
hazardous wastes under 40 CFR 261.32
and 261.33 and will be managed in
subtitle C hazardous waste facilities.
Also, commenters contended that the
contributibtl that industrial solvents will
have on the solvent power of a solid-
waste-landfill leachate is small
compared to the contribution from
solvents in household and small
quantity generator waste.
. Other commenters, however,
expressed their support for EPA's
proposal to characterize a waste by its
ability to leach hazardous constituents
from co-disposed wastes. They urged
that a method be devised to monitor the
influence that solvents have on the
solubility of other waste constituents.
One commenter suggested that the TCLP
leachate could be tested for its ability to
dissolve hazardous waste.
After careful consideration of the
comments on this issue, EPA has
decided not to include a solvent
override in today's revision of the TC.
EPA is not convinced by commenters
who stated conclusively that
mobilization of toxicants in municipal
landfills by industrial solvents is
improbable. EPA also is not convinced
that the solvent contribution of
industrial wastes at municipal landfills
is small compared to that of household
waste and small quantity generator
waste. Moreover, the comparison to
household waste and small quantity
generator waste is not relevant to the
issue of whether industrial wastes
should be regulated based on solvent
properties. However, the Agency does
agree that there is insufficient data
concerning the degree to which
industrial solvents would mobilize other
hazardous constituents and the amount
of solvent wastes that are actually land
disposed. Given this lack of data, a
solvent override has not been included
in today's rule. However, an override
may be considered in future rulemakings
if information becomes available that
indicates a characteristic based on
solvent properties is warranted.
One commenter claimed that RCRA
does not authorize the imposition of
restrictions based on toxicity simply
because a substance can mobilize other
constituents. The commenter asserted
that the authority may reside elsewhere
in RCRA, but in that case, a separate
rulemaking, not involving the TC, should
take place. -.'-. •• •
EPA does not agree; RCRA clearly
authorizes EPA to regulate a waste as
hazardous on the basis of its ability to
mobilize other constituents. Further,
regulating a waste as hazardous based
on its ability to mobilize other
constituents could be appropriately
achieved through the characteristic
mechanism. A solid waste is defined as
hazardous if its "physical" or
"chemical" characteristics "may pose a
substantial present or potential hazard
to human health or the environment
when improperly treated, stored,
transported, disposed of, or otherwise
managed" (RCRA section 1004(5)). The
capacity to mobilize toxic constituents
falls within the definition of a physical
or chemical characteristic of a waste
which may pose a substantial
environmental or health hazard. Thus,
EPA may incorporate this approach into
its characteristic waste identification
scheme in the future.
Related to the issue of solubilization,
another commenter asserted that if a
chemical's capacity for mobilization is
considered, treatment implemented to
prevent mobilization (e.g., stabilization,
containment, and chemical conversion)
should be given equal consideration.
The TCLP does consider
immobilization in the context of the co-
disposal mismanagement scenario. The
TCLP was developed to simulate
leaching in a municipal landfill,
addressing the degree of mobility (or,
conversely, immobility) of both organic
and inorganic compounds. Wastes that
have been treated to prevent
mobilization are less likely to leach
toxic constituents. Such wastes may
cease to exhib.it the TC and would
therefore no longer be considered
.hazardous wastes. Thus, the TCLP
already accounts for immobilization of
toxic constituents in a waste. However,
if wastes that have been treated to
prevent mobilization fail the TC, EPA
believes that the wastes in question
should be managed as hazardous
wastes.
B. Constituents of Concern
As noted above, the proposed TC rule
identified 52 constituents that, if present
at specified levels in a waste extract,
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11810 Ifcdmal Register / Vol. 55. No. 61 / Thursday. Mardi 29, 1990 / Rules and Regulations
would render the waste "hazardous"
under RCRA subtitle C. Fourteen of the
constituents were-already encompassed
by the existing EPTC. The selection of
the remaining 38 constituents was based
on the availability of adequate and •
•verified data necessary for establishing
(1) a chronic toxicity reference level and
(2) a constituent-specific DAF. Thus, the
Agency focused on those constituents
for which there existed a promulgated or
proponed Maximum Contaminant Level
(MCL), a Reference Dose (RfDJ, or a
Risk-Specific Ddse (RSD), and for which
there were sufficient data on
environmental fate and transport
processes to support modeling of a
constituent-specific DAF. The June 13,
198ft proposal also announced EPA's
intention to expand the list of TC
constituents as additional data became
available.
1. Final List of Constituents
The Agency is finalizing the
regulatory levels for 25 of the proposed
organic constituents (see Table B-l) that
do not readily hydrolyze and for which a
steady-state subsurface fate and
transport model is appropriate. EPA
may promulgate or repropose (as
warranted) regulatory levels for the
other organic constituents at a future
date.
TABLE B*-1.—LIST OF ORGANIC CONSTITU-
ENTS INCLUDED IN THE EXPANDED TC
RutE
Benzene.
Carbon lotrachtorido _.
Chtofobunzono....
Chloroform.,
m-Crcsol_
o-Creso)«.
p-Crcsol...
... Hexachforo-1,3-
butailiena
,._ Hexachiorobenzena
.... Hoxachloroelhane
... Methyl ethyl ketone
.... Nitrobenzene
Pentachtorophenol
._ Pyrkfina
, ,_.. Tetrachtoroethytena
1,4-DichtofOboraano .._,„... Trichloroettiylane
1.2-Dtchkxocthana 2,4,5-Trichlorophenot
1,1-Dichloro«Uiylona 2,4.6-TricWorophenol
2.4-Oinifotoloona vinyl chloride
Heptachlor (and Its
hydroxide).
Constituents with regulatory levels
established under the EPTC will
continue to be regulated at previously
established levels, but will require
application of the new TCLP instead oi
theEP.
2. Toxicants Versus Indicator
Parameters
A* few commenters -recommended that
EPA abandon its current focus on
individual toxicants and rely instead on
such indicator parameters as total
organic carbon or total organic
halogens. The commenters argued that
such an approach would broaden the
effective scope of the rule and reduce
the burdens associated with making'
hazardous waste determinations.
The Agency does not.believe it would .
be appropriate to use indicators as part
of the TC. Indicators generally are used
as screening levels or to set priorities for
further investigations. They do not.
achieve sufficient specificity .for the
regulatory purposes of the TC. For
instance, the two indicators suggested
•by the commenters do not in any way
reflect differences in toxicities among
. organic constituents. Consequently, use
of these indicators could lead to both
nonhazardous wastes registering as
hazardous and wastes that are clearly
hazardous .registering as nonhazardous.
3. Method for Selecting Constituents
Several commenters questioned the
manner in which EPA selected toxicants
for inclusion in the TC proposal. Some
of these commenters charged that the
Agency's choice of toxicants was
entirely arbitrary. Others claimed that
EPA had based its selections solely on
the availability of toxicologic and
hydrogeologic data, without considering
the magnitude of the hazards presented
by the constituents.
The commenters, in general,
encouraged EPA to develop specific
procedures and criteria for deciding
which constituents should be included
hi the TC. A few commenters offered
particular suggestions for the types of
factors that might be considered in
evaluating toxicants. The recommended
factors included (1) the mobility and
persistence of the constituents, (2) the
frequency with which particular
constituents have been found in
industrial wastes or leachates from such
wastes, and (3) the extent to which
various constituents have been detected
in ground water supplies in
concentrations capable of posing
threat to buman health and the
environment.
EPA believes that its method for
selecting TC constituents is both
rational and consistent with the
statutory mandate. While selection of
constituents in today's rule id in part
based on available toxicological data, it
should be noted that both the fate and
transport of constituents and the'
magnitude of hazards posed were also
given consideration. The toxicants for
which regulatory levels are being
promulgated today are persistent and
can represent a substantial threat to
human health and the environment.
Because of the lack .of reliable data on
the frequency with which certain toxic
pollutants are found in leachates or
ground water, an approach relying on
such information would not provide an
accurate and valid basis for selecting ,
constituents. Further, where data do ..
exist concerning the frequency,at which
certain constituents are found in the
environment, accompanying information
about risk posed in the environment is
often absent. ;
Although the Agency 'proposed levels
only for toxicants for which it has
.adequate and verified data; generally
these data are available because these •
toxicants do represent a substantial'.
threat to human health and the
environment The Agency will consider
adding constituents as additional
toxicological data and other supporting
data become available; in making such
decisions, the Agency will .consider the
factors identified by the commenters.
Until such data are available, there is no
' technical basin to determine at what
level a waste is hazardous .under the TC.
• A number of ciommenters argued that
EPA was needlessly "cluttering" the
characteristic with low-priority - •.--
constituents that are either not being
produced in the United States or are
primarily found in wastes that are
already subject to regulation.
The Agency does not agree that a .
substance no longer manufactured in the
U.S. will not posie a threat from waste
disposal. Some imch substances may be
contained in products imported into the
U.S. Also, wastes generated during
cleanup at Superfund sites or RCRA
corrective action sites may exhibit the
TC due to the presence of these
constituents hi wastes disposed at some
time in the past. Further, the
constituents could be manufactured
again in the future.
Several of the .toxicants listed in
today's rule also appear among the list
. of discarded commercial chemical
products, off-specification products, and
container and spill residues, as listed in
40 CFR 261.33. A group of commenters
argued that it would be redundant to
establish regulatory levels for these
toxicants because they are already
regulated as listed hazardous wastes.
Similarly, several commenters argued
that some other listed wastes are
regulated as hazardous wastes primarily
because they contain constituents that
will be regulated under the new TC.
EPA does not agree that setting levels
for the selected toxicants would be
redundant. White it is true that; many of
the newly designated TC constituents
are constituents in wastes that are
specifically listed as RCRA hazardous
wastes, the current listings do not cover
all of the wastes treams that may contain
the TC constitueints. For example, the
commercial chemical product listings in
40 CFR 261.33 primarily encompass
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Federal Register / VpIL 55,, Np, 61. / .Thursday, .Marqh 29, .1990;/ Rules and Regulations ,, 11811
unused products and off-specification
variants of products that are generically
identified using the name of a single
toxic constituent; however, the listings
would not cover other wastestreams
containing the same constituent. The
listings in 40 CFR 261.32 specify only a
limited number of wastestreams that
contain TC constituents. As another
example, the spent solvent listings in 40
CFR 261.31 cover only those solvents
that are used for their "solvent" .
.properties (i.e., to solubilize or mobilize
other, constituents). The current listings
do not encompass process wastes where
solvent constituents are used as
reactants of ingredients in the
•formulation of commercial .cfiemical
products. The Agency has previously
stated that it is1 expanding the TC to
bring these wastestreams into the
hazardous waste management system
(see 50 FR 53317, December 31,1985).
Thus, the Agency is appropriately
promulgating TC regulatory levels for
some constituents that have been used
'as the basis for listings.
One commenter argued'that EPA's
approach in selecting TC constituents
was too restrictive, ensuring that many
toxic constituents may never be
regulated. The commenter emphasized
that reliance on MCLs, RfDs, and RSDs
does not provide a comprehensive list of
constituents for which reliable
toxicological data exist. In addition, the
commenter noted that reliance on.
human health data does not necessarily
address hazards to the environment.
EPA disagrees with the commenter's
first point. Reliance on MCLs; RfDs, and
RSDs uses the most sound toxicologic
data base available to the Agency. At
present, there are more than 365
constituents with verified toxicity levels
available for EPA'use. In regard to the'
second point, the Agency recognizes.
that factors other than human health .
effects are also important to the overall
protection of the environment, but'
points out that the purpose of this
characteristic is to identify wastes that
pose hazards to human health via a
ground water contamination route. In
regard to the other factors, the Agency is
supporting a research effort focusing on
the determination of action levels for
ecological effects and evaluating
appropriate exposure assessment tools.
When sufficient information concerning
these ecological risks is available, the
Agency will compare the ecological-'risk-
based levels to the TG regulatory levels
to determine whether further revisions
to these levels, based or. ecological risk,
are necessary.
4. Specific Organic Constituents
Many commenters expressed concern
over several of the specific organic
constituents that EPA proposed to.
include in the TC. The comments
focusing on specific toxicants are
. discussed below.
ft. Vinyl Chloride. A few commenters
objected to the inclusion of vinyl
chloride in the TC. They suggested that
the constituent is already adequately
regulated under the Clean Air Act* the
Safe. Drinking Water Act, the Toxic
Substances Control Act, and the Food,
Drug, and Cosmetic Act (for food
contact applications).
The commenters- are correct in stating
that vinyl chloride and polyvinyl
chloride are already regulated under
other environmental health and safety
statutes. However, none of these other
regulatory authorities address the
specific problem of ensuring against ,
releases of vinyl chloride caused by the
improper management of solid wastes
containing this constituent. Most
importantly, none of the authorities
directly protect ground water supplies
from vinyl chloride contamination.
Because vinyl chloride is known to be
toxic to humans and has been detected
in ground water supplies, EPA believes
that regulating the constituent under
RCRA will add significantly to the
protection of human health and the
environment. An analysis completed as
part of the Regulatory Impact Analysis
(Ref. 8) of this regulation indicates that
large quantities of wastes currently not
regulated as hazardous contain
concentrations of vinyl chloride above
the regulatory levels. Therefore, the
Agency believes that RCRA regulation
under the TC is an important expansion
of the overall regulatory coverage of this
constituent which poses a threat to
human health and the environment.
b. Bis(2-chloroethyl) Ether. One
commenter questioned whether
incorporating bis(2-chloroethyl) ether
into the TC is appropriate, since only an
extremely limited quantity of the
constituent could potentially be released
into the environment. The commenter
noted that the constituent is used almost
exclusively as an intermediate in the
production of ionene polymers.
Moreover, it is handled primarily by a
single'facility, which either recycles the
material or destroys it by
. biodegradation prior to discharge under
a National Pollutant Discharge
Elimination System (NPDES) permit.
The Agency is not promulgating
standards for bis(2-chlorbethyl) ether
today. As discussed in section III.E.2.a.7,
bis(2-chloroethyl ether)'is expected to
hydrolyze significantly during transport.
EPA does not have sufficient data to
address the formation and toxicity of
hydrolysis products. Thus, the Agency
expects to address appropriate
regulatory action for this constituent,
along with the other hydrolyzing
constituents, in a future Federal Register
notice.
c, Toxaphene. One commenter
questioned the need to include
toxaphene in the list of TC analytes. The
commenter argued that toxaphene has
not been produced in the United States
for several years and that generators
should not be required to test their
wastes for "phantom" constituents that
are unlikely to be present.
EPA recognizes that toxaphene is no
longer produced domestically. However,
because previously generated toxaphene
wastes are still being managed in
treatment, storage, and disposal
facilities there is still a potential threat
to human health and the environment
from improper management of wastes
containing this constituent. Thus, wastes
containing toxaphene above the
regulatory level should be managed as
hazardous waste's.
Moreover, toxaphene has been
regulated as an EP constituent since
1980 and today's rule retains the existing
regulatory level. Thus, today's rule does
not alter any regulatory requirements
with respect to toxaphene. The Agency
does not believe that maintaining
toxaphene as a TC constituent is
unnecessarily burdensome to the
regulated community. The final TC rule
does not require solid waste generators
to test their wastes. Instead, generators
may continue to determine whether their
wastes exhibit the hazardous waste
characteristics by relying on their
knowledge of the materials and
processes that they employ (see 40 CFR
262.11(c)(2)). Accordingly, generators
who have reason to believe that their
wastes contain no toxaphene are not
specifically required to test for that
constituent.
d. Phenol. One commenter urged EPA
to delete phenol from the list of TC
constituents of concern because phenol
biodegrades. under both aerobic and
anaerobic conditions.
The Agency is not including phenol in
today's rule because the steady-state
assumption used in the model to
calculate DAFs in this final rule may not
be appropriate for phenol. The Agency
will promulgate a TC regulatory level for
phenolat a later date.
The issue of biodegradation is
discussed in section III.E.2.a.9 as it
pertains to phenol and other
constituents.-
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11812 Federal Register/ VoLss. No. ^61 / Thursday^ March29.1990/gules JMUJ regulations
a Pentachlorophenol. The Agency is
considering revisions to the regulatory
level for pentachlorophenol (PGP)
because new health data indicate that
POP is more toxic than originally
assumed. Two studies of different
grades of PGP material were conducted
by the National Toxicology Program,
and the new data indicate that PGP is
carcinogenic in male and female mice
under the conditions of the bioassay.
These studies were used to support die
proposal to list additional wastes from
the wood preserving industry (53 FR -
53202, December 30,1938).
The Agency is today finalizing the
higher regulatory level for PCP although
the Agency expects that the regulatory
level will decrease in the future. EPA
has determined that it is more prudent
to effect control at a higher level during
the period necessary to take comment
on the appropriateness of modifying the
TO level.
5. Specific Inorganic Constituents
As noted earlier, EPA did not propose
to add any new inorganic TC
constituents in the June 13,1986
proposal. Nevertheless,, the Agency
received a large number of comments
addressing the eight metallic species
that were already covered by the EPTC..
The Agency also received many
comments on the possibility of
proposing TC regulatory levels for nickel
and thallium (mentioned in the June 13
proposal). The principal comments are
discussed below.
a. Silver. A number of commenters
urged EPA to delete silver from the list,
of TC constituents of concern. They
pointed out that a variety of studies
have demonstrated that the chief effect
of silver on humans is argyria, a blue-
gray discoloration of the skin and
internal organs. The commenters also
stated that argyria is generally
considered a cosmetic effect, rather than
a health effect, because it does not
impair the functioning of the body.
While the commenters acknowledged
that fre e silver ions may be toxic to
aquatic life, they claimed that such ions
are rarely discharged into the
environment. Moreover, they argued
that even if such ions were discharged,
they would quickly be converted into
insoluble salts, such as chlorides,
sulfides, and phosphates, ftnally, the.
commenters asserted that deleting silver
from the TC list would be consistent
with current EPA policy. They pointed
out that the Agency has not proposed a
Recommended Maximum Contaminant
Level (RMCL) for silver in drinking
water, on the gronada that flflver does .
not cause adverse health effects.
EPA acknowledges that an RMCL
(now referred to as a Maximum
Contaminant Level Goal, or MCLG) has
not been proposed for silver because the
only known adverse effect from
exposure to silver is argyria. However,
the Agency has specifically requested
comments on whether it is appropriate
. to consider argyria a cosmetic effect as
opposed to a health effect (see 50 FR
40979, November 13,1985). EPA believes
it would be inappropriate to remove
silver from the list of TC constituents
until this issue is resolved. If EPA
determines, within the scope of the Safe"
Drinking Water Act rulemaking, that
silver does not pose a threat to human
health and the environment, the Agency
will consider proposing the deletion of
silver from the list of TC constituents.
b. Chromium. Several commenters
objected to the inclusion of total ',
chromium as a TC constituent of
concern. They argued that only
hexavalent chromium (Cr(VI)) has been •
demonstrated to pose a threat to human
health and the "environment Although
they acknowledged that trivalent
chromium (Cr(HJQ) can be oxidized to
hexavalent chromium under certain
conditions, they contend that such
conversion, is unlikely to occur in ground
water environments. The commenters,
in fact, claimed that iron-bearing soils
are likely to effect the opposite
transformation, from Cr(VI) to CrflH).
Finally, they stated that even if the
oxidation reaction did occur, the
resulting Cr(VIJ concentrations would
be so low as not to present a significant
danger to human health and the
environment
EPA continues to believe that total ,
chromium concentrations should be
considered in determining whether solid
wastes qualify as characteristic
hazardous wastes. The Agency has long
been aware of the fact that trivalent
chromium is less toxic than hexavalent
chromium. Nevertheless, the Agency
also has been concerned that trivalent
chromium could be converted to the
hexavalent form under certain plausible
mismanagement conditions. It is for this
reason as well as the fact that the
NIPDWS was&sveloped for total
chromium that the regulatory level for
chromium in the EPTC was originally
established on the basis of total-
chromium concentrations (see 45 FR
33084, May 19,1980).
The Agency later proposed to amend
the EPTC so feat it would apply to
hexavalent chromium rather than total
chromium (45 FR 72029, October 30,
19SG;seeal3o43FR2217QvMayl7,
1983). TMsprupcsa!-was based on the
•fact that trivaHent chromhuH has
significantly lower-migratory potential
than hexavalenl chromium and is less .
mobile if.it does migrate from a waste
matrix. At that time, the Agency also
believed that there was little,likelihood
that Cr(in) could oxidize to Cr(VI) under
most plausible types of improper waste
management ', ,'
More recent evidence, however, .
suggests that the conversion from
trivalent to hexayalent chromium may
' occur in a number of environmental
situations (see 51 FR 26420, July 23,1986,
m. 6). For example, Crflll) has been .
found to oxidize readily to CrfVI} under
conditions found in many field soils.
This reaction is catalyzed by manganese
dioxide, which is commonly present in
both 'soils and sediments. Moreover, it
has been shown that water treatment
involving chlorination will effectively
transform CrfHTJ to Cr(VI). The normal
presence of residual oxidizing capacity
in treated water is capable of ,
maintaining dissolved chromium in the
higher valence state (50 FR 46966,
November 13,15185). Thus, if trivalent
chromium is present in high,
concentrations in well water,
chlorination can result in
correspondingly high concentrations of
hexavalent chromium at the point of
exposure (i.e., al. the tap).
For these reasons, EPA's original
concerns regarding the potential for
trivalent chromi'iim to be converted to
hexavalent chromium remain. Thus, the
Agency believes that the prudent course
is to regulate total chromium
concentrations under the TC. It should
be noted that because of this, the
Agency is considering proposing the
deletion of the exclusion for specific . ..
chromium wastes that contain virtually
no hexavalent diromium [see 40 CFR
261.4(b)(6)(i)j. Such a change would
affect certain wastes from the leather
tanning and finishing industry (as well
as certain sludge from the production
of TiOz pigment using chromium-bearing
ores by the chloride process).
c. Nickel and Thallium.- Several
commenters expressed support for
incorporating nickel and thallium into
the list of TC anulytes. One commenter
emphasized that unless such a step is
taken, a major inequity will continue to
exist in the regulation of listed and
unlisted wastes 'that contain comparable
levels of nickel. Many other
commenters, however, objected to the
inclusion of nickel and thallium in the
TC. Most of these commenters doubted
whether either element poses a -threat to
human health and the environment,
. noting that neither one is on the Primary
or Secondary Drinking Water .Standards
list.
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Federal Register / Vol. 55, No. 61 / Thursday, March 29, 1S90 / Rules and Regulations 11B13
EPA has decided not to add more
metals to the TC constituent list at this
time because technical issues remain as
to their subsurface fate and transport.
The regulatory levels for the toxicity
characteristic metals are not changed in
this rule [i.e., EPA is retaining the
regulatory levels set under the previous
EPJ pending further Agency validation
and study of the fate and transport of
metals. These validation and study
efforts are focusing on the development
of the metal speciation model
(MINTEQ);
The Agency is developing MINTEQ
for the evaluation of the mobility of
arsenic, barium, cadmium, chromium,
lead, mercury, nickel, selenium, silver,
and thallium in ground water; A
modified version of MINTEQ will be
. used in combination with a set of
generic ground water specifications and
subsurface conditions to determine
metal solubility limitations. EPA will
then use these results, in conjunction
with the subsurface fate and transport
model, to estimate dilution during
transport to the down-gradient exposure
point (See discussion pf the
development of the subsurface fate and
transport of metals at 51FR1653,
January 14,1986.) The Agency is not
specifically proposing an approach for
evaluating the fate and transport of
metals in today's rule, but does expect
to propose, at a later time, DAFs specific
to metals,' including nickel and thallium,
and will address comments relating to
the toxicity of nickel and thallium at
that time.
C. Chronic Toxicity Reference Levels,
The Agency proposed to use chronic
toxicity reference levels (combined with
DAFs} to calculate leachate
concentration limits for individual
constituents; a waste containing
constituents equal to or above those
levels would be a hazardous waste
under the TC. Specifically, EPA
proposed to use the MCLs promulgated
as part of the National Interim Primary
Drinking Water Standard (NIPDWS),
where available, as the starting point for
establishing the regulatory levels for
each of the constituents. For those
constituents for which no MCLs had
been promulgated, the Agency proposed
to use oral Reference Doses (RfDs) and
Risk-Specific Doses (RSDs) to develop
chronic toxicity reference levels for the
noncarcinogens and carcinogens,
respectively. Because exposure to toxic
constituents can occur by multiple
pathways, the Agency also proposed to
apportion the acceptable health risk
level of each noncarcinogenic
constituent among the various possible
routes of exposure. The Agency solicited
public comment on: (1) Whether RfDs
and RSDs are appropriate to use when
MCLs are available; (2) the health levels
proposed for RfDs and RSDs; (3) the
associated risk levels; and (4) the
assumptions used to apportion exposure
to the different possible routes. The
Agency's decisions regarding the health-
related issues for which it solicited
comments are presented below.
1. Maximum Contaminant Levels
The original toxicity characteristic—
the EPTC (40 CFR 261.24)—used the
NIPDWS developed under the Safe
Drinking Water Act as the toxicity
levels to derive the regulatory levels for
the eight metals, four insecticides, and
two herbicides then regulated. (For ease
of discussion, the acronym "MCLs" will
be used in subsequent sections to refer
collectively to both MCLs and the
existing NIPDWS.) EPA plans to
continue this approach in the expanded
TC for those constituents for which
MCLs are available.
A number of commenters expressed
support for the use of MCLs, when they
exist, as the starting point for
calculating regulatory levels for the TC.
Most of these commenters argued that
the MCLs prqvide adequate protection
of human health. These commenters
stated that MCLs are reliable,
scientifically defensible, and recognized
and understood by the general public.
Several commenters supported the use
of MCLs because factors relating to cost
and available treatment technology may
be considered along with health effects
in the development of the standards.
These commenters asserted that MCLs
represent a reasonable balance among
the factors EPA must consider, while
RfDs and RSDs are more limited. A
number of commenters also felt that the
use of MCLs provides a level of
protection consistent with other
regulatory programs.
!n contrast, other commenters
supported the use of RfDs and RSDs as
the basis for the chronic toxicity
reference levels even when MCLs are
available for those constituents. These
commenters stated that health-based
levels are an appropriate starting point
for the regulation. Because the MCLs
consider other factors relating to
technical and economic feasibility in
addition to toxicity, they contend that
the RfDs and RSDs are preferable. Many
of these commenters also supported a
consistent approach for all constituents
regulated by the TC, rather than using
MCLs for some and RfDs and RSDs for
others.
Several commenters asserted that
because the MCLs were developed for
the purpose of regulating the
concentrations of constituents in treated
water "at the tap," it is not appropriate
to use the .same standards for defining
hazardous wastes. Several commenters
also expressed concern that the MCLs
developed under the Safe Drinking
Water Act are potentially more stringent
than RfDs and RSDs. This concern was
most strongly expressed regarding
'carcinogens, for which Maximum
Contaminant Level Goals (MCLGs),
previously referred to as Recommended
Maximum Contaminant Levels (RMCLs),
are set at zero, and MCLs are set at
technically achievable levels that most ;
closely approach this zero goal.
EPA maintains that the MCLs, when
they exist, are the most appropriate,
health criterion to use as the starting
point for developing the regulatory
levels. The exposure scenario developed
for the TG is based on ingesting
contaminated drinking water, and
because MCLs are developed for
regulation of drinking water, they
.clearly are relevant. In addition, the
development of the MCLs follows a
rigorous methodology in which all
available health information is
evaluated in establishing the MCLGs.
The MCLs are set as close to the MCLGs
as is feasible, and the Agency believes
that MCLs are protective of human
health.
It should be noted that EPA evaluates
the health risks that are associated with
various contaminant levels in order to
insure that the MCL adequately protects
the public health. For drinking water
contaminants, EPA sets a reference risk
range for carcinogens at 10~* to 10~s
excess individual risk from lifetime
exposure. Most regulatory actions in a
variety of EPA programs have generally
targeted this range using conservative
models which are not likely to
underestimate the risk. Since the
underlying goal of the Safe Drinking
Water Act is to protect the public from
adverse effects due to drinking water
contaminants, EPA seeks to insure that
the health risks associated with MCLs
for carcinogenic contaminants are in the
general range of 10"4 to 10" 6.
EPA acknowledges that use of MCLs
will, in some cases, result in chronic
toxicity reference levels that are lower
than those that would be calculated
using the RfD methodology. For
example, many of the non-carcinogenic
compounds have MCLs which are
approximately 10 to 20 percent of their
respective RfDs because exposure
sources other than contaminated
drinking water are considered in setting
the MCLs. On the other hand, the MCLs
for some of the constituents addressed
in the proposal are higher than the
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11814 Federal Register / Vol. 55. No; 61 / Thursday. March 29. 1990 / .Rules and Regulations
levels that would be calculated using the
RSD methodology. An example of this
situation arises when the health criteria
are at such low levels that analytical '
methods are not available to measure
those levels. In cases where the MCL is
higher than a purely health-based level,
the Agency notes that use of the MCL is
not inconsistent with today's rule since
the purpose of the rule is to identify
wastes that clearly pose hazards, not to
identify the lowest level of hazard.
However, regardless of whether they are
higher or lower than the levels
calculated using the RID or RSD
methodologies, EPA believes that MCLs
are the appropriate starting point for
developing regulatory levels for the TC.
For the constituents lacking MCLs,
EPA must rely on the available
methodologies to provide chronic
toxicity reference levels that are
scientifically defensible and protective
of human health. EPA believes that the
RfO and RSD methodologies meet these
two criteria. EPA also realizes that
inconsistencies will exist when different
methodologies are employed, for
developing regulatory levels. The
Agency intends to evaluate newly
promulgated MCLs to determine on a
case-by-case basis whether the TC
regulatory level will change significantly
if the new MCL is used, and to revise the
regulatory levels, as appropriate. In the
long run, this should provide internal
consistency for the TC, as well as
consistency with other regulatory
programs.
Some commenters supported the use,
of MCLGs as the basis for chronic
toxicity reference levels under the TC
because the MCLGs are based on health
effects alone, whereas the MCLs
consider other factors as well, such as
economic and technical feasibility.
EPA disagrees with the commenters
who stated that MCLGs are more
appropriate than MCLs for use in the
TCi MCLGs are nonenforceable health
goals for drinking water, which are to be
set at levels that would result in no
known or anticipated adverse health
effects with an adequate margin of
safety. The Agency has adopted the
policy of setting the MCLGs for probable
human carcinogens (Group A and B,
carcinogens) at zero. If the Agency were
to use MCLGs rather than MCLs in the
TC, the regulatory levels for defining a
waste as hazardous would be based on
health criteria that, at least for
carcinogens, are more stringent than the
criteria used to set concentrations
acceptable for direct human ingestion of
drinking water. In addition, the
regulatory levels would be virtually
impossible to detect analytically. This
would mean that any waste that
contains detectable levels of
carcinogens would be hazardous
regardless of the potency of the
carcinogen or the risk presented by that
waste. EPA believes that this is an
inappropriate approach for the TC
because it would result in the regulation
of wastes which are not necessarily
hazardous.
2. Risk-Specific Doses for Carcinogenic
Constituents ,
For constituents for which no MCLs
have been established, EPA uses oral
JlSbs to develop chronic toxicity
reference levels for carcinogens. The
RSD'is an upper-bound estimate of the
average daily dose of a carcinogenic
substance that corresponds to a
specified excess cancer risk for lifetime
exposure. A predetermined risk level
and the oral carcinogenic slope factor
estimated by EPA's Carcinogen Risk
Assessment Verification Endeavor
(CRAVE) Workgroup or Carcinogen
Assessment Group (GAG) are used to
.calculate the RSD.
The Agency proposed a risk level of
concern based on the weight of evidence
regarding carcinogenicity of each
constituent. Constituents classified as
known or probable human carcinogens
(Group, A or B) were assigned a risk
level of 1 in 100,000 (i.e., lO"5); while
constituents classified as possible
human carcinogens (Group C) were
assigned a risk level of 1 in 10,000 (i.e.,
10a«).
The Agency received comments
regarding both the weight-of-evidence
approach for establishing risk levels and
the risk levels selected. In particular,
one commenter supported the Agency's
proposal, stating that a Single risk level
is not appropriate for all constituents,
and that use of the weight-of-evidence
approach avoids making regulatory
decisions based on insufficient data.
Another commenter also supported the
use of weight-of-evidence to assign risk
levels, but stated that it is inappropriate
to regulate.both known and probable
human carcinogens at the same level of
risk. Alternatively, a third commenter
asserted that the weight-of-evidence
approach is inappropriate because (1)
new information is constantly being
developed on the health effects of toxic
constituents, so the weight of evidence
is constantly changing, and (2) the
classification scheme does not take into
account the potency of the carcinogenic
risk. , , '
The.Agency also received specific
comments regarding both the Weight-of-
evidence approach and the selection of
specific risk levels. Several commenters
, addressed the risk level at which 'the
Agency proposed, to regulate
carcinogens. Some commenters
specifically expressed support for EPA's
proposal to regulate Class A and B
constituents at a 10~8 risk level and
Class C constituents at a 10~4 risk level.
One commenter stated that because the
• procedure for .developing risk estimates
is extremely conservative, the proposed
risk levels would not adversely affect
human health ami the environment.
Another commenter noted that the
stated risk levels are estimates of the
upper confidence^ bound of risk and not
the maximum likelihood estimate; thus,
the actual risk to the public would be
less than the stated level.
Other commenters supported the use
of a iXT'risk level for all carcinogens.
These commenters argued that the use
of the proposed risk levels represents a
serious weakening in EPA's regulation
of carcinogens and is inconsistent with'
other policies in isffect in other EPA
programs.
With respect to the weight-of-.
evidence approach, the Agency has
decided to establish a single risk level of
concern for all potential carcinogens
(i.e., the Agency will not assign a
specific risk level to a specific weight-of-
evidence. carcincgenicity classification
for this ruleimaking). The weight-of-
eyidence approach for classifying a
constituent as,carcinogenic is based,,
primarily on the amount and quality of
data that are aveiilable rather than the
strength of the toxic response in animals
or humans. In effect, it is a qualitative
assessment that takes into.account the
uncertainty in the data for determining
whether an agent is carcinogenic to
humans. This means that the actual
quantitative difference in risk between
an "A" and "B" carcinogen as classified
by the weight of evidence may either be
zero or may be orders of magnitude.
Thus, EPA believes that both the weight-
of-evidence and the strength of the toxic
response (i.e., potency) should be
considered in making regulatory
decisions within the context of the TC.
With regard to the specific risk level
chosen, the Agency has decided to set
the level for carcinogens (Groups A, Bt
and C) atl-ih 103,000 (i.e., lO'8) for the
final rulemaking, Characteristics are
established at levels at which the
Agency has a very high level of
certainty that a waste which exhibits
these properties needs to be managed in
a controlled manner (i.e., as a hazardous
waste). The. Agency realizes that not all
wastes which exhibit properties at
concentrations below the regulatory
levels are necessarily safe for disposal
as nonhazardouu wastes. Rather,- those
wastes having-properties lower than the
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Federal Register / Vol. 55, No. 61 / Thursday, March 29. 1990 / Rules and Regulations 1183.5
regulatory levels and which are
^demonstrated to pose a hazard to
human health or the environment still
•remain subject to waste-specific
•evaluations under the hazardous waste
3'isting program. Wastes which are
determined to require controlled .
management after consideration of the
factors identified in 40 CFR 261.11(a)(3)
(e;g., the nature of the toxic constituents,
toxicant mobility under various
environmental management scenarios,
volume of waste generated and potential
method of'management) are then
specifically listed as hazardous wastes
and subjected to the appropriate RCRA
^management controls. This reflects
EPA's philosophy, first articulated in
May of 1980, that the characteristic
defines'broad classes of wastes that are
•clearly hazardous, while the listing
process defines some wastes that may
«ot exhibit the characteristics but $xe
nonetheless hazardous wastes (45 FR
33111, May 19.1980).
The chosen risk level of 10~s is at the
midpoint of the reference risk range for
carcinogens (1(T4 to 10"6) targeted in
setting MCLs, This risk level also lies
within the reference risk range (10~4 to
10" •) generally used to evaluate
CERCLA actions. Furthermore, by
setting the risk level at 10~s for TC.
carcinogens, EPA belieyes that this is
the highest risk level that is likely to be
experienced, and most if not all risk will
be below this level due to the generally
conservative nature of the exposure
scenario and the underlying health
'criteria. For these reasons, the Agency
regards a 10~s risk level for Group A, B,
and C carcinogens as adequate to
delineate, under the TC, wastes Jhat
clearly pose a hazard When
mismanaged.
3. Apportionment of Health Limits
EPA proposed to account for potential
exposure from sources other than theTC
scenario by apportioning the RfD-based
chronic toxicity reference levels. The
apportionment scheme effectively
reduced each such chronic toxicity .
reference level to 50 percent of its
original value, (i.e., 50 percent of the
RED). The Agency also proposed to
estimate environmental partitioning of
the apportioned health limits in air and
•water according to a, simplified
fractionation scheme using Henry's Law
Constants {HJ-and octanol- water
coefficients {K,,w) for individual
constituents. The" Agency did not
propose-to apportion the chronic toxicity
reference, levels based on RSDs or
MCLs.
Several coromenters addressed the
Agency's proposal to apportion the
RfDs. Commenters that criticized the
Agency's proposed apportionment
scheme argued that it was arbitrary,
overly conservative, and unnecessary.
Several commenters recommended that
EPA either use more realistic estimates
of exposure based on the available
constituent-specific data or not
apportion at all.
After a review of comments on the
proposed regulation and consideration
of the available data, the Agency has
decided not to apportion in this
rulemaking. Although the concept of
apportionment has some scientific basis
in that individuals are exposed to-many
of the chemicals of concern through
more than one route of exposure and
from more than one. source, the
implementation of the concept is very
difficult when adequate data on the
amount of exposure arid/or health
effects from all routes of exposure do
not exist Thus, due to the lack of
sufficient data to determine an
appropriate apportionment factor for the
various constituents, the Agency now
concludes that its proposed
apportionment scheme cannot be
supported at the present tune. Of course,
the proposed apportionment would deal
with uncertainty by erring on the side of
safety; nevertheless the Agency believes
that the conservative approach used to
deal with uncertainty in the
development of the RfD is sufficiently
stringent to define those wastes that
clearly pose hazards. This approach is
in accordance'with the Agency's
treatment of noncarcinogens. The
Agency therefore will not apportion the
RfDs for this rulemaking.
A few commenters criticized the
Agency's proposed method for
fractionating the apportioned RfD
between air and water. These .
commenters questioned the technical-
basis, of the Agency's approach and/or
recommended alternative schemes. The
Agency agrees with commenters that the
technical basis for supporting
fractionation as proposed is inadequate
to predict media-specific concentrations.
The Agency is exploring the
development of an appropriate model.
Thus, EPA has decided not to apportion
the RfD and not to fractionate the RfD
between air and water in this
rulemaking.
Other commenters addressed the
• apportionment of RSDs for carcinogenic
constituents; Several of these
commenters agreed with EPA's decision
not to apportion RSDs, stating that doing
so' would.result in very low regulatory
thresholds for some constituents. The
commenters also pointed out that many
conservative assumptions are already*
; incorporated into the development of the •
RSDs for carcinogens. Others
commented that RSDs should be
apportioned because humans are
exposed to these constituents by
multiple routes.
The Agency continues to believe that
it is not appropriate to apportion the
RSDs for carcinogenic constituents.
RSDs are estimated by a procedure that
must deal with unavoidable
uncertainties and is therefore
intentionally conservative. The Agency
stated in the preamble to the proposed
rule that a difference in dose of a factor
of 2 is still well within the margin of
uncertainty of the estimated RSD {51 FR
21667, June 13,1986).
Table C-l presents chronic toxicity
reference levels for the constituents in
today's rule. The Agency received a.
number of comments on specific chronic
toxicity reference levels. In some cases,.
EPA Responded to these comments in
the notice of proposed changes to the
health levels on May 19,1988 (53 FR
18024). Other chemical specific
comments are addressed in the
background document (Ref. 3),
TABLE C-1.—CHRONIC TOXICITV
REFERENCE LEVELS
Constituent
Barium
• Benzeno..n ,
Cadmium i ..
Carbon tetrachtoride... .......
Chlordane« ; , ..«..«. ..
Chtorobe'n2en6» - ....
Chloroform , :....
Chromium.™
o-Cresol ....... .
m-Cresol ....... ....
p-Creso) '
2,4-D .
1,4-Dichlorobenzene....;
1 ,1 -Dlohloroethylene
2,4-Dinitrotoluene......
Endrin ....'. „ •
Heptachlor (and its hydrox-
• ide).
Hexachlorobenzene
Hexachloro-1,3-b'utadiene.-
Hexachloroethane ...
Lead.... ..... '
Lindane ....„
Methyl ethyl ketone
Nitrobenzene .
Pentachlorophenol
Pyfidine '...„..... .....
Selenium . .'......... .
Silver. :.
Tetrachloroethytene.... ......
Toxaphene. k
Trichtoroethylene ,
2,4,5-Trichlorophenol ........ „
2,4^6-Tn'chlorophenol ......„...„..!.
2.4.5-TP acid (Sih/ex) ...„..„.
Chronic
toxicity
reference
level (mg/
005
t.O
0.005
0.01
0.005
0.0003
1
0.06
0.05
2
2
2
0.1
0.075
0005
0.007
0.0005
00002
0.00008
0.0002
0.005
0.03
005
0.004
0002
0 1
2
002
1
0.04
001
005
0:007
0005
0.005
4
0.02
0.01
Basis
MCL
MCL
MCL
MCL
MCL
RSD
RfD
RSD
MCL
RfD
RfD
RfD
MCL
MCL
MCL
MCL
RSD
MCL
RSD
RSD
RSD
RSD
MCL
MCL
MCL
MCL
RfD
RfD
RfD
RfD
MCL
MCL
RSD
MCL
MCL
RfD
RSD
MCL
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11816 Federal Register / Vol. 55, No. .61 / Thursday, March 29, 1990 / Rules and Regulations
TABLE C-1.—CHRONIC TOXICITY
REFERENCE LEVELS—Continued
Constituent
Vinyl chloride ..............................
Chronic
toxtetty
reference
level (mg/
0.002 '
Basis
MCL
A» RSDs are cah?ulatod at the 10-» risk level.
D. Use of Generic Dilution/Attenuation
Factors (DAFs)
In the May 19,1988 supplemental
proposal, EPA requested comment on an
alternative strategy for setting DAFs in
the TC. The alternative involved setting
DAFs for these constituents in two*
phases. The first phase would use a
generic DAF in a manner similar to the
existing EPTC, which uses a DAF of 100
for all HP constituents. In the second
phase, the Agency would further
address the manner in which the DAFs
are calculated and would either: (1)
Continue to use generic DAFs, (2)
employ a subsurface fate and transport
model to develop constituent-specific
DAFs, or (3) use some combination of
the two approaches. The Agency also
specifically solicited comment on the
use of a generic DAF of 100 or 500 in the
first phase.
Many commenters recognized the
need to expeditiously promulgate the
TC; however, most opposed the two-
phased approach, arguing that it would
cause undue economic burden by: [1)
Forcing industries to design new
treatment programs for one group of
wastes at certain regulatory levels, and
a few years later to redesign in order to
accommodate new levels and wastes,
and (2) over-regulating certain chemical
substances under the first generic-DAF
phase that may then not be regulated
under the second phase. Some
commenters were concerned, on the
other hand, that EPA would set the
generic DAFs so high (to avoid
, overregulation) that some substances
would be under-regulated.
Most commenters opposed the use of
generic DAFs and urged EPA to retain
the constituent-specific modeling-
approach. These commenters argued
that a generic DAF would be arbitrary
and not scientifically defensible; that
use of the generic DAFs would violate
the statutory requirements to develop a
process that accurately assesses
leaching ability and differentiates
between hazardous and nonhazardous
wastes; and that the diversity in dilution
and attenuation attributes across the
constituents would cause any generic
DAF to either severely urtder-regulate or
severely overjregulate a large number of
the constituents, Even those .few
commenters who supported the two-
phased approach recommended that the
Agency move rapidly to the second
phase and employ the modeling ,
approach to set DAFs.'
EPA acknowledges {hat the problems
noted by the commenters'are important
ones. The Agency requested;comment
on the generic DAF approach because of
the likelihood that the issues
surrounding the proposed fate and
transport model for establishing
constituent-specific DAFs would not be
resolved.in a timely manner. Since the
Agency has been able to address the
concerns regarding the subsurface fate
and transport model for the'constituents
identified in today's regulation, the ,
Agency has decided to use the model to
develop DAFs. Consequently, the DAFs
set in today's rale for nonhydrolyzing
constituents for which the steady-state
solution is appropriate are not viewed
by EPA as interim and are supported by
the subsurface fate and transport model.
The Agency intends to establish DAFs
for constituents not addressed in today's
rule on a constituent-specific basis, and
regulatory levels for those constituents
will be proposed or promulgated (as
warranted) at a later date.
E. Application of a Subsurface Fate and
Transport Model
1. Introduction
On June 13,19EI6, EPA proposed an
approach (see 51 ,FR 21648) for
estimating regulatory concentration .
levels' in a waste leachate Using chronic,
toxicity Deference levels, combined with
constituent-specific dilution/attenuation
factors (DAFs) derived from the
application of.a subsurface fate and
transport model. The model
(EPASMOD) was! first described for
public comment on January 14( 1986 (51
FR1602). , . .
, A DAF represents a reduction in the
concentration of a constituent expected
.to occur during transport through ground
water from the bottom of a disposal unit
to a drinking-Water source. In response"
to the proposal and supplemental
notices (see Section II, Table II.l), the
Agency received numerous comments
on the subsurface fate and transport ,
model used for the calculation of DAFs.
This section describes the different ;
proposals related to the use of the
subsurface fate and transport model, the
modifications to the model in response'
to public comments,'and the results
obtained with the use of the modified
model.
a. June 13.-198S Proposed Rule (51FR
21648j^Ihe Agency'JB June 13,1986
proposal used a subsurface fate and
transport model l[EPASMOD) to
calculate specific DAFs for each of the
44 organic hazardous constituents (see
Table E-l). The DAFs for each
constituent were calculated using the
model, incorporating compound-specific
hydrolysis and sdil adsorption data;
coupled with parameters describing 'the
subsurface environment (e.g., ground
water flow rate, hydraulic conductivity
of the aquifer, ground water pH, etc.).
The Agency proposed modeling a
scenario of wasts mismanagement.at a
subtitle D municipal landfill. Data were
incorporated in the model using a monte
carlo simulation:
TABLE E-1.—DILUTION ATTENUATION FACTORS FOR TOXICITY CHARACTERISTIC ORGANIC CONSTITUENTS
Constituent
ACtykK)Hri!^*.iiiiit.ti.iiiiiitTit-ii-r-yTn-iiTiv-- iti-t-t— ^ i— •' "-*1 - .«»«.
B(j(2-chtoroathyl)ether «.„. _' . .,. .».«. ...«. :.'. «.«
Carbon d(sulfkte«*«.«*«.««««*«».«*.».«..»...«.«.«.«M..»....w «...«..«....•..—.• ;
Carbon totrachtorida" ' -. J. .......... ; „_....•....
fj)\!nfrijlng • t ^ ^
o-Crojo) „«,... .. .:..« .-. - '..I'...::.,...,.,...,.,
nvCrftSd t ,,',',,..,, .„ 1 _
2 ^.P ' '„!
1i2*Ofchlofob1/yr .:.........;...;.......
NHYFA...: •
»H • ;
NH
NH_ ; ;....
NH
NH
NH .;...
NHYF ....
NHYF „
NHYF* .'.. ;.
NHYF..:. ......~......
NH
Kb"
>1/yr ..'...:..........'.......
NHYF _ -
NH , ;
>10/yr.......;......j
NH
>10/yr ,...,....:...
1E-6/hr......i
0.23/rir.. ~.......
NHYF i
NHYF
NHYF...:,..'...:. :.
NHYF......."..-,:.
1E-5/hr
.'KM..
>1/yr .............:.. ...:.
NHYF. .. :...:
8E-5/hr ...
NH
NH .....
NH :........ :....
NH i..............:
3E-9/hr. ;...;.......
NHYF .'.
NHYF..™
NHYF '. «...
NHYF ...;.: .........
NH
D/A
factor9 •
14U
14.4
14.4,
14.4
14.4
14.4
14.4
14.4
14.4
14.4
14.4
1'4.4
14.4.
-------
Federal Register /
;/ Thursday March %9, 1990 f MteS^nd -R^ufeftofer
TABLE E-t.—DILUTION ATTENUATION FACTORS FOR TOXICITY CHARACTERISTIC ORGANIC CONSTITUENTS—Continu'ed
Constituent
1 2-Dichtoroethane ' •
1,1-Dichtoroethylene .. . .... I....7... '..".. . . • "" .-. ".: '''.•".
2,4-Dinitrotoluene ; ..'......". '. .„.„ ;.;•„. .'.
Endrin.. ; ...„„ ;..- .;.. ..:..
Heptachlor (and its hydroxide) ........:.... .;. .'. .'..; .'.
Hexachlorobenzene .....'... '.;..:...-...'.'.'
Hexachlorobutadiehe .... ; ; .»...»........:..'......; .:......
Isobutanol . ; . . .
Methylene chloride , .» «»...... :....
Methyl ethyl ketone :.. .".......... :...... „..'...:.-. „.'..„
Nitrobenzene . . . .: .v....
Pentachlorophenol .; ..'......... '...
Phenol .; : .;;.-.
Pyn'dine '
1,1,1 ,2-Tetrachloroethane _...
1,1,2,2-Tetrachloroethane ;
2,3,4,6-Tetrachloropnenol
ToxaphenQ ;......„.....„.„
1,1,1-Trichloroethane
1 1 2-Trichtoroethane ' ' ' .. . ..
2,4,5-Trichlorophenol :. ..
2 4 6-Trichlorophenol ' ..''-.. ,.; ...
2,4,5-TP (suvex) ,...:.....; ..„ .......„.,..:.'. ........... „...;..
Vinyl chloride :., ..„
LOG
Kow V
3.56
1 40
'2.13
2.30
*3.54
7 4.61
642
4.24
422
074
3.40
T4;30
1,26
0.30
1.90
5.06
1.49
0.68
2.81
2.42
3.03
4.33
2.82
7 5.30
2.50
1 91
228
3.86
3.58
3.45
1.38
Ka*
NLFG • ....... :
NH :
NLFG
NLFG ;.:.
>1/yr :....
NLFG
<1/yr
NLFG;..:.
>1/yr ... '-',..
>1/yr
>1/yr
NH
NH :.....
NLFG.... ....'.........
NLFG
NH '.....
NHYF ......;
NLFG .'.
NH
NH
NLFG
NH...
NHYF
NH ....„:
NH
NH.i.....; :..
NLFG :...
NH
NH..... :
NLFG
NH. i
Kb"
NLFG.... i
NH
NLFG '.' ' ;. .. '
NLFG :'.; :.•..;....
>1/yr ;...,
NLFG......;. .'..
<1/yr
NLFG :....
>1/yr
>1/yr. ,....
>1/yr
1 4/hr
NH: :
NLFG... ....
NLFG ....:.'
>1E-4/hr
NHYF
NLFG
1 3/hr
2.6E+ 3/hr
NLFG
1E-5/hr
NHYF .'.
>10/yr
NH .....;...;....
13/hr
NLFG ;.
1E-5/hr..
1E-5/hr.....
NLFG .
1E-5/hr.... ..'.
Kn8
NLFG .
.7 2E-5/hri '.
NLFG.....
NLFG ..:..........
>1/yr .
NLFG .:...
<1/yr
NLFG i...
>1/yr
>1/yr
>1/yr
7.5E-5/hr .........
1.18E-8/hr
NLFG....:
NLFG....
NH '..:..:
NHYF
'NLFG
2.2E-7/hr ;„...
NH
NLFG
NH
NHYF
NH ;
1.1E-4/hr
4.3E-7/hr
NLFG :
NH
NH
NLFG
1E-7/hr
D/A'
factor "
14.4
75.0
14.4
14.4
14:4
14.4
14.4
14.4
14.4
14.4
14.4
14.4
14.4
'14.4
t4.4
14.4
14.4
14.4
14.4
65.0
14.4
14.4
14.4
14.4
150.0
20.0
14.4
14.4
14.4
14.4
14.4'
1 Logarithm of the octanpl/water partition coefficient
2 Acid, base and neutral hydrolysis rate constants.
3 Dilution/attenuation factor derived from ground water transport system.
» NHYF = No Hydrolyzable Functional Group.
"NH = Negligible Hydrolysis.
? NLFG = No Liable Functional Group.
1 Estimated value.
In the monte carlo simulation, values
for each parameter ar.e based upon the
frequency distribution for-each
parameter (where such data exists)
rather than the selection of a single
value for each parameter. The model is ,
then run a sufficient number of times
(typically several.thousand) to produce-,
the frequency distribution of the model's
output. This'overall frequency
distribution is, effectively, a
combination of the frequency
distributions for each, individual .
parameter. This approach avoids the
compounding effects of conservatism
inherent in choosing single, reasonable-
worst-case values for each parameter.
Monte carlo simulation was chosen as
.the preferred method to analyze the full
range of possible environmental
conditions for the land disposal
scenario. The wide range of .
environmental conditions (e.g.,- ground
water velocities, pH, temperatures,.
exposure point locations) that can'exist
in locations across the nation where the
wastes in question may be disposed
precludes a priori specification of a
reasonable worst case for these
parameters. Another important reason
to .use the mor te carlo method is the
very complex-manner in which the many
model variables and parameters.
interact/Unless many (hundreds to ,
thousands) combinations of variables
are investigated, it is simply not possible
. to anticipate those physical settings that
lead to unacceptably high exposure '
levels. Accordingly, the monte carlo
method was chosen to ensure that-a
conservative but not physically
unrealistic or impossible analysis was
completed.
the EPASMOD, as described in the
proposed rule, was based on a number
of key assumptions pertaining to the
features of ground water flow,
properties of the porous medium, and
the behavior of hazardous wastes in
"ground water; These assumptions
included the following:
• Saturated soil conditions (no
.attenuation of chemicals in the
unsaturated zone);
• Flow regions of infinite extent in the
. longitudinal direction, semi-infinite.
extent in the lateral direction, and finite
• in the vertical direction;
' • Aquifer can be characterized by
homogeneous and isotropic properties
and the aquifer thickness is constant;
• Ground water flow is uniform and
continuous in direction and velocity;
• Degradation is limited tq hydrolysis
and the fay-products of hydrolysis are
assumed to be nonhazardous;
• Contaminants follow a linear
equilibrium adsorption isotherm;
• 'An infinite source supplies a
constant mass flux of chemical into the
aquifer;
• -Recharge due to precipitation
• supplies water .to'the disposal unit and
the aquifer;
• The ground water upstream of the
disposal site is initially free of
contamination;
• The Receptor well is directly in line
with the source and the ground water
flow direction;
• The receptor well is located 500 feet
from the unit; and
• Hydraulic conductivity does not
vary with temperature. ,
In the June proposed rule, the Agency
also proposed using the 85th cumulative
percentile level of the back-calculated
dilution attenuation factors obtained
•• using the monte carlo simulation
technique as an appropriate regulatory
level for the TC. Selection of this level
means that downgradient
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11818 Federal Register / Vol ,55,-No. 61 / Thursday. March 29, 1990 / Rules and Regulations
concentrations will not exceed the
allowable health-based concentrations
in more than 15 percent of all possible
analyzed settings of subtitle D disposal,
units. (This proposal referenced other ,
proposals dealing with the ground water
transport model, such as the January, 14,
1986 Land Disposal Restrictions notice,
and notices published by the delisting
program; relevant comments received in
response to those notices are also
discussed in'this rulemaking.)
b. August 1,1988 Notice of Data
Availability and Request for Comments;
Supplement to Proposed Rule (52 FR
28892). On August 1,1988, the Agency
presented new data related to subtitle D
municipal landfills, soil characteristics,
and chemical-specific hydrolysis rates
to be used with the subsurface fate and
transport model to calculate DAFs for
each of the organic constituents in the
TC. These new data became available
to the Agency after the June 13,1986
proposal. The August 1,1988 Notice also
requested comments on several major
revisions to EPASMOD that were being
considered by the Agency, subsequently
referred to as EPA's Composite Model
for Landfills (EPACML). As a result of
comments received on the January 14,
1988, and June 13,1986 proposals,'as
well as the August 1,1988 Notice, the
Agency has used EPACML to support
the choice of appropriate DAFs for this
rulemaking.
These modifications and data are
described in greater detail below
(section IH.E.2). The reader is referred to
the Responae-to-Comments Background
Document for the Subsurface Fate and
Transport Module [Ref. 1), which
presents, in detail, each of the technical
issues addressed in the public comments
on the model and the Agency's response
to these issues.
2. Modifications of the Subsurface Fate
and Transport Model (EPASMOD) in
Response to Comments
In today's rule, the Agency has used
EPACML to estimate the attenuation
and dilution of specific constituents
during their migration through the
unsaturated zone beneath a municipal
landfill and their transport through the
saturated zone to a potential drinking
water source (exposure point). EPACML
accounts for dispersion in the
longitudinal, lateral, and vertical
directions; one-dimensional steady and
uniform advective flow; sorption; and
chemical degradation from hydrolysis.
The major enhancements that were
made to EPASMOD to produce
EPACML, the substantive comments
that led to these changes, and important
assumptions made to develop analytical
solutions are described in subsection (a).
below.
In addition, the Agency used the
EPACML. model to corroborate its
conclusions on dilution/attenuation
factors, for surface impoundments. For
this exercise, data inputs typical of
surface impoundments rather than
landfills were used. These procedures
are described in subsection (b) below.
a. General Modifications—i.
Unsaturated Zone, The EPASMOD
model discussed in the June 13,1986
proposal assumed that there was no
unsaturated zone (i.e., the bottom of the
landfill is directly connected to the top
of the aquifer). Several commenters,
stated that the assumption that the
facility is located directly at the top of
the saturated zone is unrealistic because
an unsaturated zone usually exists
above the aquifer and that retardation,
dilution, and degradation effects in the
unsaturated zone should be considered.
The commenters also suggested that,
when incorporating the unsaturated
zone, the depth to the water table
should-be incorporated as part of.the
monte carlo analysis.
The Agency is in agreement with the
commenters and has now included an
unsaturated zone as part of the
subsurface model. The Agency believes
that this modification to the model is
reasonable, based in part on a survey of
existing municipal landfills that
indicated that an unsaturated zone
exists beneath 95 percent of the
surveyed landfills. Incorporating an
unsaturated zone into the model
accounts for any retardation and
degradation of chemicals in the
unsaturated zone and provides a more
realistic scenario.
To account for the unsaturated zone,
the Agency developed unsaturated zone
flow and transport modules and
implemented them using the monte carlo
(probabilistic] framework that has
already been used in conjunction with
the saturated zone modeling approach in
EPASMOD; these unsaturated zone
•modules are incorporated into EPACML.
The input concentration to the
unsaturated zone transport module of
EPACML corresponds to the leachate
concentration at the bottom of the
•landfill.
The unsaturated zone model was
reviewed by EPA's Science Advisory
Board (SAB). The SAB endorsed the use
of the model for applications for the
development of regulations; however,
the SAB recommended that it not be
used for site-specific applications
because the model has-limitations
imposed by the simplifying assumptions
(those necessary for regulatory use), and
the limitations of the use of site-specific
data. The unsaturated zone model
consists of two modules: a.flow
component and solute transport
component: These two components were
developed in a form to allow for their
incorporation in "the monte carlo
simulation. The major assumptions and
consequences of the flow module are:
» Flow is steady in the vertical
direction, and lateral and transverse
movement of the leachate is negligible:
Because there is little or no lateral flow
in the unsaturated zone, these
assumptions are appropriate. In any
case, this procedure will tend to
maximize the concentration of leachate
• leaving the unsaturated zone and
therefore represents a conservative
assumption. .
• No vapor phase or immiscible
liquid flow acorn's, and the water phase
is the only flowing material. EPA
acknowledges that some constituents in
some situations may undergo phase
shifts arid be emitted in vapors. Because
this rule is essentially directed,to risks
from drinking waiter and because of the
uncertainties in accurately computing
emissions and their relationship to the
currently available leaching tests, this
conservative assumption was adopted.
Under certain conditions, particularly
very high constituent concentrations,
immiscible liquid! flow can occur. For
such situations, the model's inability to
account for the immiscible flow
condition may lead to higher
downgradient concentrations (i.e., the
model would underestimate the receptor
well concentrations).
• Flow is isothermal (not affected by
temperature variations). In reality,
temperature variations at any given site
are not dramatic because the source of
infiltrating liquid, is precipitation. Thus,
this assumption iis not expected to
influence the results to any appreciable
degree.
• Effects of variations in the
unsaturated zone hydraulic properties
caused by alternating moisture
conditions are negligible (i.e., hysteresis
effects). Many soils, especially the more
porous ones for which infiltration rates
are high, do not present important
hysteresis effect:). In other cases, little
and often no data are available to
characterize the effects. Failure to
include hysteresiis is not expected to
affect the results to any appreciable
extent.
• The flow field is uniform and
continuous in direction and velocity.
Precipitation-driven infiltration can be a
dynamic process where much of the
vertical movement occurs during
relatively short periods o£ time. Time-
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Federal Register / Vol; 55, No. 61 / Thursday, March 29,, 1990 / Rules and Regulations 11819
averaged values of infiltration derived
from dynamic water balance :
calculations (as described in the
Background Technical Support
Document) are often used to enable
solution of analytical, steady-flow
models. The unsteady-flow conditions
could lead to higher downgradient :
concentrations than predicted by
EPACML. However, the effect is
expected to be significant only for
rapidly degrading constituents. For the
constituents regulated in this rule, no
appreciable impact is expected because
none of the constituents are expected to
hydrolyze to ,ariy significant extent •"• '
during transport.
• The unsaturated zone is
homogeneous and isotropic. This
assumption is typically required to
enable mathematical solutions
amenable to exhaustive/sensitivity
analyses and monte carlo
implementation; In any one application
(one model run) of this assumption, the
result can either under- or over-predict
downgradient concentrations. The
monte carlo implementation, however, •
results in a very wide range of possible
conditions, .and thus the total analysis,
when taken together, accounts for a
wide variety .of unsaturated zone
conditions. . ; • •-.,..-
The major assumptions and
consequences of the urisaturated zone
transport module are: , ... • ;
• Chemical transport is vertical; <
lateral and transverse mQyemeftt of the
chemical is negligible. .This follows from
the first assumption for the flow module
described. -abpve. ,
•' Chemical sorptiqn is modeled as a
reversible, linear equilibrium, process.
This is a standard modeling assumption
which .is accurate for systems having
relatively low solute, concentrations, and
conservative at highest; Concentrations.,
», Degradation is limited 'to '
hydrolysis. This assumption' was made
. to be consistent with!,the similar • ..'
approach adopted for fee' saturated
-zone. Thus, the model includes only
those degradation mechanisms that can ..
be reliably characterized^ laboratory '
. studies of each individual' constituent.
, This assumption remains a major, . .
conservative, cbmpb&ent of the. overall
model. ..... .....
• Chetnfcal transport in the vapo?*
phasejias been assumed tQ:be'
''
which this assumption is appropriate is
discussed in section III.E.4(b)(iii).
The details of the unsaturated zone
module are provided in the background
documents (Ref. 1, 9), which also
describe the data sources arid analyses
that were performed to obtain the data
distributions.
ii. Source Characterization. In
EPASMOD, the input leachate to the
saturated zone was assumed to be
instantaneously mixed in the vertical
direction over a pre-specified depth of
source penetration, and the , •' :
concentration in the leachate was equal
to the maximum source contaminant
concentration in the saturated zone
below the facility. Mass balance
considerations required that the lateral .
extent of the leachate directly
underneath the facility be adjusted to
ensure that leachate was neither gained
nor lost in the transition from the facility
(or unsaturated zone) to the aquifer. A
number of commenters criticized the ,
treatment of the source. A major
concern was that the method was
inadequate because of an overly •
conservative assumption, which equated
the concentration of the contaminant in
the saturated zone to the landfill
leachate concentration. Thus,
commenters argued that EPA had not
given adequate consideration to mixing
and dispersion under the laridfilLThe
commenters also pointed out that' this
treatment of the source could result in
mode.ling physically unrealistic' ! _' -
boundary conditions (e.g., by modeling ;a
source of small- cross-sectional area with
a very large width of the Gaussian ',
source, and vice vers'a}/
The Agency agrees with the
commenters that the method used to
characterize the source-boundary
conditions for the saturated zone
transport needed to be improved. Thus,
the'niethod has been revised to consider
the.mass balance requirements,
gebirteMcai;configuratidris, arid phy'sical
processes': that are occurring iri.'the'
mixing zone below the facility 'and
within the saturated zone. An important
characteristic of the revised method is ,
the pluirie restriction in the lateral
extent, ^hatis,: the method no.lbriger .
' petmits .physically unrealistic situations
wKere the plume source width exce'eds
'''-'''''
assumption, for the flow module
described above, ,
*'The 'unsaturated zone 'transport-
•model' is solved for the s^feady-stjajke
condition. This is a c'orise'rvative
assumption that has beefririyesitigated;
"for its impact on all the origfn$lly. "
proposed constituents' :The extent to :
.....
: cutteht methbb* bf comjjuthig the source?
boundary 'conditions represents; -the
miking' and dilution effect on the
le'acnate';below the.source 'and' ensures
ffiat t^ieicdhc'e'ritratipn pftfie
cpnfljtiinnant in' the saturated,zbne ivill
beTess'thian or equal to the landfill '
leachate'Cbncerttl'ation. '
.
Recharge: In EPASMOD, the dilution
effect of ground water recharge on
contaminant transport in the saturated
zone was taken into account by
including recharge as a dilution term in
the governing equation. Dilution of
leachate concentrations from recharge
was calculated by dividing the
infiltration'(recharge) rate by the source
penetration depth. A number of
commenters were concerned that the
. influence of recharge on the ground
water flow field had not been properly
' 'accounted for in the model. In addition,
several commenters alerted the Agency
to an error in the equation used to'
evaluate the recharge dilution
parameter.
In response to these comments, the
Agency has modified the model to
calculate dilution from recharge by
dividing the recharge rate by the total
saturated thickness of the aquifer, the
aquifer porosity, arid the effective
retardation, factor in this zone; This
revision represents a more realistic
.assessment of the dilution potential of.
recharge by considering changes in the
entire volume of water in the
contaminated aquifer and the
effectiveness of contaminant arid
recharge flow and iriixing in the a'quifer.
The. Agency recognizes that recharge
effects.on ground water flojiy fields are
not rigorously considered in the'model
and that the assumption of uniform,
constant, horizontal ground .water
velocity neglects the possible effects of
local mounding Of the. watet table
unclerijeath the -land disposal unit.
iJoweyer, the constant velocity
assumption can be interpreted as an
averaging of the velocity field over.-the
spatial:a"rea affected :by: recharge! in
addition, the uniform', horizontal flow.
assumption was necessary to make the
threie-dimensibrial transport equation,
analytically solvable. The effect of
recharge on ground water velo'city is
idiffieult .to account for difec.tl'y in the
model.;T-o assist ui the Analysis; EPA
has conducted'a sensitivity analysis'
comparing EPACML res:ults with
recharge effects as predicted'by a two-
dimensional numerical model that
rigorpusly accounts for recharge. The.
: results (which can be found in Ref. 9) -
indtcated^hat; as long a^ recharge valaes •
• are slghififcaritlydess than fhre :Mtural
flow velbcity, mere was npi'mdjor-e'ffe'tt
on fee ground watet:flow fields. Bashed
on thiS'aiEialysis, and on evidence of
typically low;rates Of ground tyater
refcharge, .the •Agency believes tnat the
revised treatment of the dihitipn effect
from reGharge is reasonable-jln'additigri,
•• the errpjr,-.as pointed b.utbyjseyerjal
eontinentefs, in th.e equatijoh used ta1
evaluate the recharge dilution
-------
11820 Jfeder alRegister /Vd.55.Ng. 6j_/giursday. March 29, 1990 /
parameters was corrected, and'the
correction is included in EPACML.
iv. Location of the Receptor Well. In
EPASMOD, the receptor well was
assumed to be located downgradient
from the landfill along the centerline of
the plume (direction of ground water-
flow) at a fixed distance of 500 feef
(152.4 m). In addition, the receptor well
was assumed to be tapping water from
the top of the aquifer, and no mixing of
water in the well or effects of drawdown
in the well were considered in
EPASMOD.
Many commenters argued that the
assumptions concerning the location of
the receptor well were too conservative
and suggested that well locations should
be considered in a probabilistic manner
as part of the monte carlo simulation in
the model These commenters noted that
well locations other than on the
centerline should be considered. Several
commenters also stated that the well
locations should not be restricted to
lying within the areal extent of the
plume and suggested that wells located
outside of the plume should be
considered in the calculation of the
dilution/attenuation factors.
The Agency agrees that the proposed
location of the well was-unrealistic and
that affected wells located at points
other than on the centerline should be
considered. Therefore, the model now
considers well locations anywhere
within the areal extent of the
contaminant plume. In order to
incorporate these locations, a
distribution of distances to
downgradient wells was developed
based upon a subtitle D municipal
landfill survey (Ref. 6). These distances
were used as part of the m'Onte carlo
analysis. Also, to incorporate locations
other than on the centerline, the Y
values (see Figure 1} were selected
randomly over a 180° domain but the X-
Y pairs were constrained to values that
-were located within the areal extent of
the plume.
BILLING CODE 6560-50-M
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Federal Register / Vol. 55. No. 61 /- Thursday. March 29. 1990 / j*"]es a"d Regulations^^ 11821
I
A SCHEMATIC OF THE HASTE FACILITY SOURCE BOUNDARY
COttDITION AND LEACHATE HISRATION THROUGH THE
yHSATURATED AMD SATURATED ZONE
PLAN VIEW
SECTION VIEW
Monitoring
-•Wei! Ground Surface
Water Table
Aquifer
3
V
BILLING CODE 65SO-50-C
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11822 FederalRegJ8ter/.VQl.g5,No.-61 /Thursday. March 29, 1990 / Rules and Rggplgtiorur
The Agency disagrees with those
commenters who stated that well
locations outside of the areal extent of
the plume should be considered. The
purpose of the Toxicity Characteristic is
to answer the question "if the
management of this waste continues to
be uncontrolled, what are the
consequences in terms of human
exposure via ingestion of contaminated
drinking water,?" In performing the
exposure assessment to answer this
question, the Agency believes it
appropriate to consider only wells that
could be affected by the disposal of the
waste. Wells that could not be affected
by the migration of constituents from the
wastes are obviously irrelevant to the
exposure assessment and, thus, not
considered.
Commenters also stated that it was
unrealistic to assume that the well
tapped'water from only the uppermost
point of the aquifer. These commenters
stated that, in practice, the intake
portion of a well is located below the
top of the water table and that mixing
and drawdown will occur.
The Agency agrees that the proposed
well intake location was unrealistic and
that it ignored the effects of vertical
mixing and the possibility that the well
intake would likely be at some point
other than the top of the aquifer. In
response, the assumption has been
modified to consider well intake at any
point throughout the depth of the
aquifer. This modification largely takes
into account the above-described mixing
and drawdown effects.
In determining how to account for
well drawdown more realistically in the
model, the Agency considered the
mechanics of well construction.
Generally,'wells are screened from near
the top of the aquifer to a sufficient
depth (into the aquifer] to allow delivery
of the needed water supply. Thus, the
ranges of values for the length of the
screens and their locations relative to
the top of the aquifer are very large. In
recognition of this variability, especially
in screen length, the Agency has
employed a simplifying assumption the*
the concentrations of constituents at
various depths of the'aquifer represent
the concentrations at the exposure
point. That is, the concentration of. ,
constituents in, the water drawn from
the well is assumed to be equal to the
concentration of the constituents at the
depth which is selected in the monte
carlo simulation. (The well depth is
randomly selected from all points within
the vertical range of the aquifer's
thickness.)
To evaluate the model's sensitivity to
this assumption, the Agency evaluated
the case in which wells were .assumed to
be .screened, from, the top of the aquifer
to the monte-carlo-selected depth.. The
exposure point concentration was then
calculated as the average concentration
over the. screened depth. This case is
considered to be more representative of
• the most likely well design, although in
many cases the well will not extend to
the bottom of the aquifer nor will it .
always be constrained to intersect the
plume as is implemented in the monte
carlo simulation. This scenario is >. .
considered to be more conservative,(i.e.,
resulting in lower DAFs) than the
•EPACML-as-implemented scenario.
When one considers other possibilities
like well location factors up gradient
and outside the plume, the range of
DAFs from the two scenarios can be
expected to bound the actual exposures.
In evaluating the model predictions
over the range of cumulative frequency
values considered in interpreting the
model's results in today's rule (see
Section III.E.4—DAF Evaluation), the
dilution/attenuation factors for the two
scenarios are not sufficiently different to
warrant separate conclusions regarding
the appropriate value for use in today's
rule. (Model results for the two
scenarios are compared in the
background document for the model—
Ref. 9.)
v. Dispersivity Values, Dispersivity
controls the degree of spreading of
dissolved contaminants in the
subsurface. The saturated-zone fate and
transport model includes dispersion in '
the longitudinal, transverse (horizontal),
and vertical directions. The model thus
requires values of the longitudinal,
transverse, and vertical dispersivities hi
the saturated zone. In EPASMOD, the
distance x from the downgradient edge
of the landfill to the receptor well was
assumed to be fixed at 152 m (500 feet).
Consequently, fixed values of the
longitudinal and transverse
dispersivities were used in the model.
The values of vertical dispersivity were
assumed to-vary uniformly.
Several commenters criticized the
assumption that dispersivity values did.
not vary and reflected only the fixed
distance selected in the model. They
also suggested that the ratio of
longitudinal to transverse dispersivity
used in the model was too low. The
basis of their comments is that field
values of dispersivities have been
shown to depend on, and usually
increase with, the travel distance.
The Agency agrees with the
commenters and now calculates the
three components of dispersivity based
on a detailed analysis of data gathered
from field tests (the model background
document [Ref. 9] presents a detailed
discussion on dispersivity values and
provides references to the field data).
The Agency believes that the revised ±:\
approach, reflecting the distance-
dependent nature of the dispersivity
values and different relationships vi
between the dimensional dispersivities,;
is more realistic and consistent with the
available data.
EPACML also requires, the , • . ,.;
specification of a dispersivity parameter
for transport in the unsaturated zone.
Since the transport equation in the
unsaturated zone is one-dimensional,
only the longitudinal (vertical)
dispersivity value is required and is
calculated as a function of the distance
(i.e., the depth to water table) traveled
in the unsaturated zone. *
;, -vi. Hydraulic Conductivity. In
EPASMOD, the value of hydraulic
conductivity in the saturated zone was
estimated using the Kozeny-Carmen
(Ref. 9) expression, which relates
• hydraulic conductivity to porosity, the
mean particle diameter of the aquifer
material, and the fluid properties
(density and viscosity). This relationship
was,based on an assumed ground water
temperature of 15 degrees C and did not
reflect changes in the fluid properties
with temperature!.
Commenters expressed concern with
this assumption because ground water
temperature is known to typically range
in temperature from 4 degrees G to 30
degrees C. A few commenters also
expressed concern regarding the validity
of using this empirical relationship.
In response to these comments, the
Agency gerieralteed the expression to :
include the effects of changes in
temperature oh fluid viscosity and fluid
density. That is, the fluid viscosity arid
density are now considered as functions
of temperature rather than as constants.
The Agency realizes that the hydraulic "
conductivity also depends on physical'
properties, such as grain shape, grain
size distribution, packing, and tortuosity
of the porous media. Porosity
measurements reflect the composite
result of these textural characteristics
on the structural arrangement of the
porous media. The range:of porosity
values derived in EPACML indirectly
reflect the impact of these properties.
Therefore, in view, of the Agency's
objective to represent the wide
variations expected from site to site, the
, Agency decided to retain the Ifozeny-
Carmen equation, except for the
modification described above. . -.
yii. Hydrolysis. As already discussed
in section Ili.E.2., the EPACML model
accounts for reduction in constituent
concentrations due to hydrolysis. This
results in higher DAFs for constituents
that hydrolyze'during transport than for
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Federal Register / Vol. 55, No. 61 / Thursday, March 29. 1990 / Rules and Regulations 11823
constituents that do not. The DAF
predicted by the model for some of these
constituents ranges up to one million.
Thus, in some cases, wastes would not
be considered hazardous unless they
contain large amounts of these
toxicants; still, in other cases, no
amount of toxicant in the waste would
define it as hazardous under this
scenario. Therefore, the Agency did not
believe it appropriate to include these
constituents in the TC (see Table E-2 for
list of constituents that appreciably
hydrolyze). Furthermore, the model does
not account for the degradation products
that are produced as the original
constituents hydrolyze. That is, while
the decrease in the concentration of the
original constituent is accounted for, the
resultant increase in concentration of
the hydrolysis products is not Several
commenters stated that the toxicity and
transport of the potential hydrolysis
products should be considered to fully
assess the hazards posed by the
constituents that hydrolyze.
The Agency agrees with the
commenters and is (1) determining
which byproducts result from hydrolysis
and (2) developing an appropriate
protocol for predicting the concentration
of.hydrolysis byproducts (see Table E-
2). Once this protocol is developed, the
Agency will determine whether any of
these toxicants should be added to the
list of constituents. While the Agency
. considered including these constituents
at a higher dilution and attenuation
factor, until this work was completed;
the Agency does not have sufficient
information at this time to determine
which of the constituents listed in Table
E-2 will eventually be added to the TC
and at what level.
TABLE E-2—HYDROLYZING CONSTITU-
ENTS LISTED IN THE JUNE 13, 1986
PROPOSED RULE
Acfyfonrtrito
Bisp-chioroethyl) ether
Methylene chtoride
1,1.1,2-Tetrachtoroethana
1,1,2,2-Tetrachtoroethane
1,1,1-Trictiloroethane
1,1,2-Tfichlcroethane
viii. Steady-State Assumption. As
implemented for today's rule, EPACML
was solved for the steady-state
condition. Thus, the solution represents
the Case where leaching has occurred
for a period of time that is sufficiently
long to allow the concentration at the
receptor well to become constant
Several commenters noted that, in
certain circumstances, use of the steady-
state solution would lead to
unreasonably low DAFs. In particular; in
situations where the mass of a
constituent is relatively low in the
source facility (i.e., the landfill has a
very limited quantity of the constituent
available to contaminate leachate), the
steady-state model will continue to
assume the existence of a very large
quantity of the constituent and, hence,
over-predict the resulting concentration
at the downgradient well. Under such
circumstances, the commenters argue,
the Agency should accommodate this
phenomenon by using a transient
solution in deriving appropriate DAFs.
The Agency agrees with the
commenters and has initiated a study to
thoroughly investigate the problem
described above. Based upon
preliminary investigations already
complete, however, the Agency
continues to believe that application of
the steady-state model to many
constituents is appropriate and is
promulgating regulatory levels for those
constituents based upon the results of
the steadyrstate model. The preliminary
investigations have also led to a
decision to postpone the promulgation of
regulatory levels for constituents that
are believed to be more appropriately
evaluated with a transient solution. The
Agency is continuing to refine the
approach required to implement the
transient solution but results to date
suggest that this latter group of
constituents require unreasonably large
quantities in the source facility to insure
that the steady-state solution is
appropriate. For example, under some
conditions even when the constituents
exist at concentrations in excess of 1000
ppm of the solid waste within the entire
volume of the landfill, the steady-state
condition is not realized. Therefore,
based upon the preliminary analysis,
regulation of these constituents based
upon the DAFs predicted by the steady-
state model may not be appropriate.
Preliminary investigation of this
condition was completed for all of the
originally proposed constituents. All
constituents were assumed to exist in
the "tested" waste at 1QOO ppm.
Furthermore, the "tested" waste was
assumed to occupy 100%: of the available
.facility capacity (i.e., the "tested" waste
is the only solid waste in the facility):
As a reasonable worst case scenario,
the DAF was derived by the transient.
model for each constituent under-these
conditions. Because the above
assumptions are very conservative; most
of the DAFs derived for the constituents
were found to coincide with the steady-
state values. That is, sufficient mass
was available to insure that steady-state
conditions.were reached. Accordingly,
regulatory levels for these constituents
are being promulgated in this rule. For
the following constituents, however, the
steady-state condition was not achieved
under this scenario:
phenol
1,2-dichlorobenzene
carbon disulfide
isobutanol
2,3,4,6-tetrachlorophenol
toluene
Accordingly, the Agency is postponing
the promulgation of regulatory levels'for
these six constituents until such time as
the investigations are complete. Once
these investigations are completed, the
Agency will take the appropriate action.
ix. Biodegrodation. The subsurface
fate and transport model does not
account for biodegradation processes in
the subsurface environment. EPA
recognizes, however, that
biodegradation is an important process
that can reduce concentrations under
either aerobic or anaerobic conditions.
Accordingly, the EPA has constructed
the model so that it can theoretically be
modified to include these processes for
experimentally derived biodegradation
rates, Biodegradation processes have
not been included because the data
bases to support this portion of the
model are currently, insufficient
The first major data deficiency is that
the model incorporates many diverse
subsurface environmental conditions
where as constituent-specific
biodegradation rate data typically exist
for only a few (if any) subsurface
environments. EPA also recognizes that
although the kinetic equations
describing the degradation of hazardous
organic chemicals in many
environments are available,, these
equations have not been sufficiently.
evaluated in the subsurface environment
(Ref; 10t 11,12). Second,, the Agency
considers data on the formation of
transformation products to be
insufficient. Third, the key processes
that can affect the subsurface
biodegradation rate are not well
understood. These processes include
sorptipn, pH»temperature, nutrient
availability, toxicity, and .others. For
example, while nutrient levels in the
environment are generally considered
sufficient for low populations of
microorganisms, Ihe microorganic
population at which the nutrient
availability in the environment becomes
a limiting factor is not known.
Additionally, while sorption is well
understood for hydrophobia compounds
at low; concentrations {Ref. 13), at
concentrations Where the compounds
can form small droplets or become
entrainedin the micropores. of the
-------
11824 Federal Register / Vol. 55, No. 61 / Thursday, March 29, 1990 /Rules and Regulations
subsurface matrix, sorption" effects are'
not well understood. The effects of
temperature have been characterized in
innumerable studies of isolated
microorganisms, but the kinetics of
these effects have only recently been
investigated in environmental samples
(Ref, 14). Finally, the toxicity of
hazardous chemicals to the
microorganisms themselves is only now
being investigated tRef. 15).
Accordingly, the Agency is continuing
to gather data to refine the modeling of
biodegradation, but has not been able to
include biodegradation in the ground
water transport model at this tune. In
this regard, EPA has published
guidelines for developing anaerobic
microbiological biodegradation rate
data for chemicals in the subsurface
environment (see 40 CFR 795.54). Results
developed under these guidelines will
provide data on kinetic rates of
degradation, and to a lesser extent, on
the effects of pH and temperature on
these rates. Similar guidelines have not
been developed for aerobic systems at
this time. Data developed under 40 CFR
795.54 may be considered for use in the
model at some future time.
x. Summary of General Modifications.
The Technical Background Document
(Ref. 9) describes in detail the model
revisions, including options developed
but not implemented for the purposes of
establishing the regulatory levels for
today's rule. A summary of the major
model options and procedures
implemented for the rule follows:
• The model was run for the steady-
state case. The initial condition was a
constant concentration. The equations
Were solved for infinite time.
• The unsaturated.zone module was
included in the analysis.
• Concentrations can be predicted at
wells placed at any position. The wells
can be allowed tq draw from any
selected depth.
• The updated method of computing
dlnpcraivities as a function of random
longitudinal well locations was used
(designated hi the model as the "Gelhar
procedure"). , ; '
• The option implemented for setting
the boundary conditions between the
unaaturated zone and the aquifer was
the one that limits the lateral extent of
the plume to the downgradient facility
width, computes vertical mixing and
dispersion underneath the facility, and
estimates the maximum source
concentration within the plume based
on mass balance requirements. Any
combination of conditions that violated
these requirements and, thus is not
physically realistic, Was rejected.
The above options and additional
options are listed in the background
document for the model .(Ref. 9).
Specifically, the model input and control
variables, as required and accepted'by '•
the computer code, are listed for each
computer run used to set regulatory
levels in today's rule. . .
By incorporating these modifications,
the EPACML, as applied 'to landfills,
models the following basic features:
• The landfills are filled to capacity
and covered with native-soil. • ,
•' Caps are characterized as being in e
failed or deteriorated state. Thus, ,
permeabilities are set to be higher than
would be typical of landfills with an
undamaged cap. It is assumed that'liners
are not present./
• All wells (exposure points) are
considered to be downgradient in 'every
model run. The longitudinal distance '
parallel to the direction of ground water;
flow is determined from data described
later in section III.E.3.
• Lateral well location is determined
by allowihg-the position to uniformly .
vary at random within the plume width
and with the additional constraint that :
the location also must be within an area
defined by lines at 90-degree angles,
from the direction of ground water flow
at the midpoint of the downgradient
boundary of the facility.
• Vertical well location is determined
by allowing the position of the well •
intake point to uniformly vary at
random over the entire aquifer depth.
• The landfill storage^ capacity is
assumed to be sufficient to.,
accommodate sufficient mass, of each
constituent lo allow a steady-state
condition to exist. This produces an ,
infinite source initial condition.
• Constituents contained within the
landfill dp not degrade.
• Infiltration rates are represented as
annually averaged flows based on 20-
year climatic records and concomitant
water balance calculations.
b. Use of the EPACML far Surface
, Impoundments. Because some wastes. «
are managed in surface impoundments
rather than landfills, several .
commenters indicated the need to .
analyze end include .the results obtained
by considering a surface impoundment
mismanagement scenario. They argued ,
that dilution/attenuation factors (DAFs)
generated by modeling a landfill
scenario would be too stringent'for
wastes managed in surface "'
impoundments. Based upon these
comments, the Agency decided to..
investigate whether surface
impoundment DAFs would be
significantly different from landfill
DAFs. EPA requested comment On the
. iise of this, data in the August 1,1988
.notice..
Based upon this, investigation, the
Agency has concluded that the use of
DAEs based on a landfill-scenario is
appropriate in establishing the
regulatory levelsi for wastes managed in
surface 'impoundments. EPA used the
EPACML model to confirm this analysis
by modeling a surface impoundment
mismanagement scenario.
This conclusion is based on the
Agency's evaluation of the physical
parameters that would lead to different
DAFs for surface impoundments than
for landfills. A key factor that could lead
to differences in the DAFs from these ,
two types of management units (surface
impoundments tihd landfills) is the,
.difference in total leachate infiltration
rates. The infiltration rate Js equal to the
product of the leachate mass flux (mass
per unjit area peir unit time) and the area
of the management unit. For surface
impoundments, the mass flux can be
considerably greater than for landfills.
However, to the extent that the area of
surface impoundments is typically
, smaller than the area of landfills
(although some atypical surface
impoundments can be as large,'if not
larger .than landfills), the effects of the
greater Jeachate flux are'somewhat
offset, That is, yriiile the-flux is;greater,
the area is .smaller, resulting in; •
.relatively similar leachate infiltration
rates.
Aaecond factor that affects the DAFs
is the situation in which the leachate.
fluic is large and the ground water '•.
velocity is relatively small. In these
situations, a ground water, mound-may
.form below the management unit This
effect is more typically associated with
surface impoundments because of their
higher leachate fluxes; this effect should
result in smaller DAFs (and, thus, more
stringent regulatory levels) than would
be predicted if the mounding did not;
occur. As a result of these factors, the
Agency concluded that DAFs from a
surface impoundment scenario would be
equivalent to or less than DAFs from a
landfill scenario. • ,
To confirm this conclusion, EPA used
EPACML to evaluate a surface
impoundment scenario; The main
features of thelsurface impoundment.
scenario, as sirmulated using EPACML,
are as follows:
• The surface impoundments are
filled to their fluid capacity and are
assumed to operate on a continuous
basis.
• Bottom layers are characterized as
being in a more permeable state :
(typically ten times greater) than those
found in field studies.
• Location rules for downgradieru
well positions amd lateral ar'' vp.rtica'
-------
locations are identical to landfills. The
data base for longitudinal distances is
different, however.
• The operating life of the surface
impoundment is assumed to be
sufficient to accommodate a sufficient
mass of constituent to allow a steady-
state condition to exist. This assumption
produces an infinite source initial
condition. .
• The leaching rate from a surface
impoundment depends on, among other
factors, the ponding depth in the
impoundment and the characteristics of
the bottom materials. The Hydrologic
Evaluation of Landfill Performance
(HELP) model used in evaluating the
landfill data is inadequate to determine
the leaching rates from surface
impoundments. Therefore, the leaching
rates from subtitle D surface
impoundments were estimated by
considering the relationship between the
velocity in the vertical direction and the
substrate's porosity and permeability
and the solution of the nonlinear steady
state flow problem. To be conservative,
the Agency used a permeability value
ten times higher than the value typically
reported in field studies as an input for
calculating leaching rates (the source of
these data are discussed below).
• The Agency has not yet conducted a
detailed survey for subtitle D surface
impoundments, but the Agency
conducted a review and analysis of data
on subtitle D units in RCRA Facility
Assessment (RFA) Reports (Ref 16). A
set of data on subtitle D surface
impoundments was obtained from this
analysis and used as inputs to the
EPACML. Additional data were
compiled from aerial photographs by
EPA's Environmental Photographic
Interpretation Center (EPIC).
• The data extracted from RFSs
included the area of the surface
impoundments arid the distance to
downgradient drinking water wells as
determined by EPIC.
• The ponding depth data for the
subtitle D surface impoundments were
reported by E. C. Jordan (Ref. 9). The
hydraulic conductivity of the bottom
materials was chosen as 1.0 E-« cm/sec.
This value reflects the effect of gradual
settlement and compaction of sediments
at the bottom, because surface ••
impoundments tend to fill up with
sediments over a period of about 20
years or so. The Agency believes that
the hydraulic conductivity value of 1.0
E-6 cm/sec represents a reasonable
worst-case value. These values .were
used in conjunction with EPACML to
estimate DAFs for the surface
impoundment data.
As expected, DAFs; predicted for
surface impoundments are somewhat
smaller than the corresponding values
for landfills (see section III.E.4).
However, because the EPACML does
not incorporate the mounding effect, the
surface impoundment evaluation was
restricted to include only those cases
where mounding would be minimal and,
thus, reasonably ignored. As a
consequence of limiting the evaluation
to these cases, the modeling results tend
to omit some worst case scenarios. That
is, if all possible cases were included,
rather than just the "no mounding"
cases, the DAFs for surface;
impoundments could be somewhat
lower and, thus, the downgradient
concentrations may be higher than those
estimated by the EPACML model. The
Agency thus believes that the omitted
surface impoundment conditions should
be further investigated and may result in
more stringent regulatory levels. The'
Agency believes, however, that the
DAFs produced by the EPACML
analysis properly delineate wastes that
are clearly hazardous wastes.
.3. Newly Acquired Data
As previously described, the DAFs
proposed on June 13,1986, were
calculated based on the subtitle D
landfill scenario. However, subtitle D
landfill data were not available to the
Agency at that time, and instead, .
subtitle C landfill data were used.
Several commenters criticized the use
of subtitle G (hazardous waste) landfill
data. The Agency.agreed with the
commenters and has based the final rule
on data from a survey of solid waste
subtitle D landfills.
a. Landfill Data. The Agency
conducted a survey of municipal solid
waste landfills in the U.S. (Ref. 6). The
survey used a stratified design based on
facility size. The results were tabulated
based on 1,102 completed
questionnaires. The survey yielded data
on area of landfills, distance to the
nearest downgradient drinking water
wells, and thickness of the unsaturated
zone. These data are site-specific,
corresponding to individual solid waste
landfills located throughout the United
States. The survey data were analyzed
to develop distributions of these site-
specific parameters and used as inputs
to EPACML, as described in the model
background document (Ref; 9). The input
frequency distributions are also
presented in the' background document.
EPA also collected additional-data on
leachate generation at municipal
landfills.JEPASMOD requires, as input,
the leachate distribution from: the •
bottom of the landfill. The leaching rate
distributions for the June 13,1986,
proposal were based-on the use of tr
single soil type, loam, as the cover soil
for the landfill. These distributions were
estimated using climatologic data for a
total of 30 cities nationwide, '
representing the median range for each
of 18 climatological conditions or zones-
identified in the 48 contiguous states.;'
The assumptions of a single soil type
and 18 climatic zones were criticized as'
not being realistic and resulting in an
overly optimistic cap performance. The'
commenters suggested enhancing the
data base by including simulation of
different soil covers.
In response to these comments, the
Agency has implemented a number of
changes. The Agency believes that these.
modifications significantly improve the
validity of the leachate flux distribution
and make it more realistic.
Soil Type
The Soil Conservation Service (SCS)
has a county-by-county soil mapping
program underway. More than 90
percent of the land area in the U.S. has
been mapped, and soil data representing
approximately 51 percent of the total
land area in the'U.S. have been entered
into a computer data base. Using this
data base, the soil classifications were
grouped according to the U.S.
Department of Agriculture's definitions
of coarse, medium, and fine textures.
These three categories are represented
in EPACML by soils equivalent in ' ,
properties to sandy loam, silt loam, and
silty clay loam for the landfill cover
materials. The latest results show that
coarse grained soils, medium grained
soils, and fine grained soils represent
15.4,56.6, and 28.0 percent, respectively,
of the soils that have been mapped thus
far.
Climatic Zones
The number of cities representing
climatic; variations that were used to
develop frequency distributions for the
leachate generation has been increased
from 30 to 100. The reason for this
change was to reduce the chance that
any one city would provide an
unrepresentative percolation rate in its'
climatic range.
The climatic data base used in
• EPACML was enhanced to include six
precipitation ranges and five ranges of
pan evaporation rates, thereby resulting
in 30 climatic ranges as opposed to the
18 described in the earlier proposal. For
the climatic ranges so defined, the
percentage of the area of the 48 states
represented by each range was
calculated, and the percent areal
average was used to weight the
percolation (recharge and/or .
infiltration) rate estimated for the
selected cities in each range according'
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11826 Federal Register /Vol. 55, No. 61 / Thursday, March 29, 1990 / Rules and Regulations
to probable relative occurrence in the
U.S. The effect of these changes is to
provide more representative values of
the overall national distribution of the
leachate flux.
After the percolation data for the
landfill were calculated using the HELP
model (Ref. 9), the climatic ranges were
further subdivided to account for wide
Variations in percolation within a range.
This resulted in separate subranges
being established for some California
cities (Los Angeles, Sacramento, San
Diego, and Santa Maria), and two
Oregon cities (Medford and Astoria).
Percolation rates for each of the
selected cities in the 48 contiguous
states were determined using silt loam,
sandy loam, and silly clay loam cover
soils. These soils, based on data
obtained from the SOS, appear to
represent the most common soil types in
the U.S., and thus the most common soil
to be used as covers for landfills. They
also span the range of likely cover soils,
from fine-grained to coarse-grained, or
from low to high percolation rates.
Simulations were performed for each of
these soil types, and the results
weighted according to the frequency of
occurrence for each type.
The leaching rate flux was determined
by using the average, weighted
percolation rate from the cities in each
clintatic range. The model background
document (Ref. 9} presents the data used
and the accompanying changes to the
Juno 13,1988 proposal runs.
b. Chemical-Specific Parameters. In
the EPASMOD proposal, chemical
parameters, such as hydrolysis rates.
•were used to calculate the relative
retardation factors and degradation
rates for selected compounds. Some of
the chemical-specific parameters used in
that model were estimated based on a
brief review of the existing chemical
data. Some commentera criticized some
of the parameter values selected and
used for that proposal as being
nonrepresentative of the range of
parameter values.
The Agency has an ongoing program
for the measurement of constituent-
specific parameters and for the review
of new constituent-specific data as
reported in the current scientific
literature. Some hydrolysis rate
constants and octanol-water partition
coefficients used in the proposal have
been revised to reflect the most recent
laboratory measurements and recent
values reported in the literature. The
updated parameter values are given in
the background document (Ref. 9) and
represent either measured or best
available values.
4» DAF Evaluation
a. Selection, of an Appropriate
Percentile. As described earlier, the
EPACML was used to investigate the
expected range of DAFa associated with
mismanagement of solid wastes. As
generated by EPACML, the DAF
represents the expected reduction in the
concentration of a constituent during
transport through soil and ground water
from the leachate release point (bottom
of the waste management unit) to an
exposure point (a well serving as a
drinking-water supply). The wide range
of .possible environmental settings (e.g.,
ground water velocities, pH,
temperatures, etc.} and the multitude of
possible scenario configurations (e.g.,
facility area, distance to downgradient
wells, etc.) result in an extremely wide
range of DAFs. Monte carlo simulation
was used to implement EPACML, and
the resulting cumulative frequency
distribution can be viewed as a ranked
order of increasingly higher
downgradient concentrations expected
from the "best-case" situations (large
DAFs) to the "worst-case" situations
(small DAFs) for the scenario being
investigated.
The Agency's proposed approach was
to "define DAFs representative of
reasonable worst-casfe conditions as
those corresponding to the 85th
percentile of the cumulative frequency
distribution. The Agency received
numerous comments on the selection of
the 85th percentile, which are addressed
in Section d, following.
b. Resulting DAFs for Landfills. The
DAF values corresponding to various
cumulative frequency levels for landfills
are as follows:
PercerttPe
All nondegrading constitu-
ents ,...:..-......
80
??fi
227
85
m
in-
90
51
i 52
95
is
19
Percentife
M nondegradrng eonstftu-.
Chloroform1.— .
80
328
385
85
134
152
90
47
52
95
12
14
'The DAFs for chloroform are slightly higher than
for ttis other noncfegradfng constituents because
chloroform b expected to hytfrolyze sffghtly tfitftng
transport.
The similar DAF values for
nondegrading constituents and
chloroform arises because all these
constituents either do not degrade at all
or only degrade slightly.
c. Resulting DAFs for Surf ace
Impoundments. The DAF values
corresponding to various cumulative
'frequency levels for the surface
impoundment investigations described
in E.2.b of this section are as follows:
As with the landfills, the constant
DAF for all constituents reflects the fact
that nondegraders and very slow
degraders have virtually identical
environmental fate for the scenario
investigated. As the resulting numbers
indicate, within a reasonable degree of
accuracy, the DAFs for waste managed
in surface impoundments are equivalent
to the corresponding landfill DAFs.
d. Final DAF Selection. The Agency's
purpose in developing dilution/
attenuation factors (DAFs) is to identify
wastes whose leaching behavior .,,
indicates that they may pose a hazard to
human health unless they are controlled
under subtitle C management standards.
Thus, the Agency developed a
subsurface fate and transport model that
simulates a subtitle D management unit
(i.e., a municipal landfill) and the
subsurface environment that would be
encountered by toxic constituents as ,
they migrate from the management unit
to a drinking-water well. In order to
make the model's output (DAFs) as
realistic as possible, the Agency
implemented th« model using real-world
distributions for parameter values (e.g.,
areas of landfills, properties of the
subsurface environment, etc.) whenever
possible. The monte carlo structure of
the simulation allowed the modeling ;
results to be presented as a cumulative
frequency distribution or probability.
That is, the model expresses the
probability that a toxic constituent
disposed of in a municipal solid waste
landfill will undergo certain dilution/
attenuation as it moves through a
subsurface environment to an exposure
point. Thus, theire is a different DAF for
each selected probability.
In its June 13,1986 proposal notice, the
Agency proposed the use of the DAF
corresponding to the 85th percentile
cumulative frequency level and
' requested comment on the use of other
percentile levels. Comments were
received urging the use of both higher
and lower levels. Recommendations for
using the 80th percentile cumulative
frequency were justified by assertions
that the assumptions used in the model
were already unduly conservative. One
cornmenter noted that EPA could stilt
rely on the listing program to regulate
wastes whose fcaachate concentrations
would not exceod the regulatory levels
derived from the lower percentile DAF
but that are still considered hazardous.
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Other commenters argued that the 85th
percentile was not adequately protective
of human health and the environment.
One commeriter, claiming that
assumptions in the model were not
conservative enough, recommended that
the 95th percentile be used.
In selecting the appropriate level, the
Agency recognizes that there is no
consensus "correct" level for
interpreting modeling results. This has
resulted in a particular challenge in
developing today's rule, wherein a ,
quantitative approach is being used for
guidance in answering what is a partly
qualitative question—namely, "what is
the human health impact of unregulated
management of certain types of wastes
in a 'reasonable worst-case' disposal'
scenario?" While the Agency believes
that "the 85th percentile is an appropriate
choice to represent a reasonable worst-
case result, consideration of the
relationship of the 85th percentile DAF
to other percentile D AFs is also
appropriate. That is, the Agency
believes that the behavior, or-shape, of
the upper portion of the .cumulative
frequency distribution curve, should also
be evaluated in order to determine how
critical the selection of a particular
frequency level is to the DAFi
Another consideration in determining
the appropriate DAF value, independent
of,the selected cumulative frequency
level, is the accuracy inherent in the
data set used. Given that there is some
uncertainty associated with- any :data set
.used |p represent possible values for
any parameter, and that the model
requires values for many .parameters,
the Agency believes that.the .selected
DAF value ^hould npt imply an undue
degree; of accuracy. • ' •
. After considering/the. above factors,
the Agency has concluded that a DAF
value of 100 is appropriate for
establishing the regulatory; levels for the
constituents included in today's rule.1
.First,; the Agency,beHeves,that,<
'considering the number of parameters
for which,distributioris.pf values were:
established [in order to-represent a
"generalized" scenario), a DAF .with an
prderrof-magriitude precision; is'
•' A» ex^laittecrprevloiiM^,"the-A|e;nCjr i^ lipjt, in:
tpday'ia i^e.pro'malgating'regulatqi^ levels'litfi •''
.several of the constituents for w.hich regulatory'
''those "that are expected to. hydrplyze appreciably
and'thoae for Which it has not yet beenxleteriniirted '
Whether the steady-state solution to the subsurface
.fate and.transport model is appropriate. Once the ,
'issues associated with these constituents are.
. 'resblved; tije Agency'will prpmulgate'brlfe'fif6ppse
(as'warranted) regulatory levelsfpTjthese;' • '/
constituents. For cases where regulatory levels.
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11828 Federal Register / VoL 55. No. 61/•Thursday, March 29,1990 / Rules and
The first change is the insertion of a
more detailed method flow chart to
explain how analysts are to perform the
test. Comments expressed confusion
regarding the original flow chart (e.g.,
that it was difficult to follow], so the
Agency has added this new chart to
eliminate confusion. The second change
is the addition of new equipment
suppliers to provide more information
on the availability of suitable testing
equipment. The new equipment
suppliers include two manufacturers of
rotary agitation devices, Environmental
Machine and Design, Inc., of Lynchburgi
VA, and Millipore Corporation of
Bedford, MA: two manufacturers of a
zero-headspace extractor (ZHE) vessel,
Lars Lande of Whitmore Lake, MI and
Environmental Machine and Design,
Inc., of Lynchburg, VA; and three
manufacturers of filter media, Millipore
Corporation of Bedford, MA; Nucleopore
Corporation of Pleasanton, CA; and
Micro Filtration Systems of Dublin, CA.
These manufacturers are listed in
Tables 2,3, and 5, respectively, of the
method (i.e., Appendix H of 40 CFR 261),
along with company .telephone numbers
and equipment model numbers.
Another more substantial proposed
modification, the addition of a stainless
steel cage insert to the bottle extractor,
will not be added by the Agency at this
time foe the reasons discussed below.
The Agency had proposed this
modification to eliminate the
requirement for particle size reduction
for certain typea of wastes (e.g.,
solidified materials).
3. Applicability of TCLP to Solidified
Wastes
Some commenters expressed
reservations regarding tiie applicability
of the TCLP to specific types of wastes.
The wastes of concern were solidified
wastes. Numerous commenters
supported the reinstatement of the
structural integrity procedure (SIP) or
some other stability criterion for
solidified wastes. They argued that
particle size reduction (Le., "grinding")
would be inappropriate in those
instances where solidification, of the
waste is needed to meet the best
demonstrated available .technology
(BOAT) provisions of the law and that
grinding may not adequately represent
the weathering process or the effect of
vehicular traffic. Commenters
recommended that the Agency retain the
SIP, Others agreed that particle size
reduction is inappropriate for stabilized
monolithic wastes and produces
unrepresentative results. Specifically,
commenters stated that particle size
reduction alters the physical character
of many solidified wastes by destroying
the cementitious property of these
wastes in such a way that the leaching
rate increases unrealistically. By
increasing the surface area that is
available to attack by a leaching
medium, the amount and rate at which
substances may be leached increases.
Inasmuch as waste grinding is not
normally employed in municipal
landfills, particle size reduction renders
the TCLP a less accurate model of
leaching in a municipal landfill
environment.
Since the June 13, 1986, proposal, the
Agency has reviewed the use of the SIP,
which uses a drop-hammer to test the
integrity of the waste and to reduce its
size if it fractures. The Agency found
that although the SIP may simulate the
potential of a monolithic waste to be
degraded by vehicular traffic on a
landfill, it cannot address certain other
stresses acting on the waste (e.g., wet-
dry and freeze-thaw cycles). In addition,
the SIP can only be used for wastes that
can be prepared in a sample of specified
dimensions.
While evaluating the use of the SIP,
the Agency found that dense, hard
materials would occasionally break the
glass extractor bottle. To prevent
breakage of the bottles, the Agejacy
developed a cage insert for the extractor
bottle. The cage, which is designed to
prevent contact between the hard
sample and the sides, of the bottle, is
constructed of 0.25-inch stainless steel
woven mesh. Experiments have shown
that the use of the cage prevents bottle
'breakage.
While evaluating the utility of the
cage, the Agency noticed that wastes
that were believed to be well-solidified
retained their monolithic nature in the
cage during extraction, whereas wastes
that were believed to be less well-
stabilized (even though some of them
had passed the SIP) were broken into
small pieces during the extraction. Thus,
these experiments led to the proposed
use of the stainless steel wire cage in the
extraction apparatus (53 PR 28792, May
24,1988). The use of this device, the
Agency believed, tested the physical
integrity of the sample and reduces
particle size appropriately.
Commenters expressed support for
the cage modification—that it is a step
in the appropriate direction •toward a
more realistic assessment of the
environmental leaching potential of a
solidified waste. However, commenters
also had concerns that the cage was
proposed prematurely—that not enough
evaluation of waste samples using the
cage had been done. Specifically,
commenters argued that the cage could
possibly leach significant quantities of
nickel and chromium to contaminate
metals analysis; Ithat it would be
difficult to collect representative
samples in some cases; that there were
problems with the configuration of the
cage so that it could not be . .
accommodated to fit a large array of
bottles; that the cage's construction
provided numerous crevices and a
significant amouiit of surface area for
waste residue to collect, making
effective cage cleaning difficult; and that
solidified samples could be molded into
a shape that would cause less material
to be sloughed off during extraction,
leading to a less aggressive test. The
Agency agrees with these commenters
and has decided not to go forward with
the cage modification at this time. The
Agency currently has work underway to
evaluate all these concerns, and will
continue to evaluate modifications of
the TCLP and will propose further
improvements as they are developed.
4. Analytical Methods
Several comments addressed the
analytical difficulties of analyzing the
TCLP extract for phenolic compounds
and phenoxy acid herbicides by gas
chromatography/mass spectroscopy,
SW-846 Method 8250 (GC/MS). These
analytical difficulties include the
interference of title acetate ion in the
TCLP leach fluid with the column
packing material of Method 8250.
Removal of the a eetate ion is often
difficult, and equipment damage may
result if the acetate is not removed (i.e.,
the acetate ion can destroy the column
packing material).
The Agency agrees that analysis for
acidic compounds by GC methods may
be difficult, but not impossible. The
Agency suggests the use of a bonded-
phase capillary column (Method 8270) to
reduce the interf erenee from acetate. In
addition, the Agency is investigating
other methods fear removal of the acetate
ion from the extract before analysis for
the phenotics and herbicide and
welcomes alternative suggestions,
especially when accompanied by
supporting data.
The Agency had suggested the use of
HPLC as an alternative to GC/MS
, analysis of phenolics and phenoxy acid
herbicides. However, several
commenters believed that an HPLC
method is generally regarded as more
expensive and not as readily available
as GC/MS. In addition, some
commenters indicated that GC/MS is a
better method analytically than HPLC,
and that HPLC would be more difficult
to implement. The commenters
expressed that, at the very least, a
lengthy verification process would be
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Federal Register / Vol. 55, No. 61 / Thursday, March 29, 1990 / Rules and Regulations
11829
required to determine an HPLC method's
ruggedness and reproducibility and to
determine the most effective cleanup
steps. The commenters further suggested
that even if an effective HPLC cleanup
procedure is developed and approved by
the Agency, it is bound to increase the
' analytical costs and slow down the
analytical throughput. Even without
considering this restriction, the
procedure of leaching the organics Into
an aqueous medium, followed by
extraction, recovery, and concentration,
is bound to require more manpower and
thus more money than a more direct
solvent extraction of the solid itself. The
commenters indicated that methods for
analyzing solid waste for semi-volatile
organics and phenoxyacid herbicides
are already described in SW-846 and
should be the preferred methods, both
for practicality and as a way of
providing a reliable test
The Agency agrees that the GC/MS or
GC/electron capture (GC/EC) analysis
is more advantageous for the analysis of
phenolics and phenoxy acid herbicides
because the equipment is more readily
and widely available tiian HPLC,
despite the associated difficulties, HPLC
methods for phenolic compounds are not
included in the.third edition of SW-84B
because of a lack of validation data. The
Agency will allow only the use of the
GC/MS method until such time that the
Agency pioposes an HPLC method.
G. Testing and Recordkeeping
Requirements
1. Existing Requirements for Generators
Under existing regulations, persons
who generate solid waste are not
specifically required to test their wastes
to determine whether they exhibit the
characteristic of EP toxicity or any other
characteristic. Instead, solid waste
generators are required to make a
determination as to whether or not their
wastes are hazardous (40 CFR 262.11].
If a waste is found to be excluded
from regulation under § 261.4, or if it is
found to be a listed hazardous waste
under subpart D of 40 CFR part 261, no
further determination of hazardousness
is necessary. On the other hand, if a
waste is neither excluded nor listed, the
solid waste generator must determine
whether it exhibits any ofthe hazardous
Waste characteristics in subpart C of 40
CFR part 261. This determination may
be made by either testing the waste or
applying knowledge of the waste, the
raw materials, and'the processes used in
its generation.
If a waste is determined to be
'hazardous, the generator must keep
records establishing the-basis for that
determination (40 CFR 262.40(c}). These
records must be maintained for at least
3 years after .the generator no longer
handles the waste in question. Neither
of these recordkeeping requirements,
however, applies to solid waste
generators who do not generate
hazardous wastes.
Other provisions in the hazardous
waste regulations make generators
responsible for knowing the properties
of their wastes and for documenting that
knowledge. For example, generators
who declare that their wastes are
hazardous must nevertheless have
sufficient knowledge of their wastes to
complete the Uniform Hazardous Waste
Manifest, to use proper labels,
containers, and placards, and to satisfy
all applicable reporting and
recordkeeping requirements {see 45 FR
12728, February 26,1980). In addition, all
generators of hazardous waste are
required under 40 CFR part 268 to
determine whether their wastes are
restricted from land disposal.
2. Changes Considered
In the June 13,1986 proposal, EPA
expressed concern that the current
system for determining whether a solid
waste is hazardous may be inadequate
to ensure that wastes are characterized
properly as hazardous or nonhazardous.
•Because of the importance of accurate
hazard determinations to the RCRA
subtitle C program, the Agency
discussed the possibility of requiring
solid waste generators to test their
wastes periodically.
In the proposed rule, EPA identified
three general approaches that might be
adopted in the TC final rule. In the first
approach, the Agency would retain the
current approach, allowing generators to
rely on their knowledge of materials and
processes used in generating wastes as
a basis for their determination. In the
second approach, EPA would require .the
testing of wastes, at a frequency
specified by regulation. Finally, in the
third approach, the Agency would
require testing but without specifying a
particular testing frequency. Under this
third approach, generators would be
required to develop an appropriate
testing frequency, based oh Agency
guidance, and to document the basis for
their choice.
Commenters were heavily divided on
the issue of testing and recordkeeping
requirements. Many commenters,
including waste management firms and
a few generators, favored mandatory
.testing of solid wastes. Most of these
commenters argued that generators
typically lack sufficient information to
determine accurately the composition of
their wastes without testing. Indeed, one"
commenter claimed that with 52
constituents regulated at the part-per-
million level or lower, a generator could
never be sure whether a waste exhibits
the TC without performing the TCLP
test. The commenters concluded that
testing is the only reliable method for
ensuring that potentially hazardous
wastes are properly identified and
managed.
Aiew commenters offered somewhat
different reasons for supporting testing
requirements. For example, some
commenters pointed out that mandatory.
testing would facilitate EPA
enforcement efforts. Others claimed that
mandatory testing would reduce
uncertainty by making it clear to
generators precisely what EPA expects
of them with respect -to performing
hazardous waste determinations.
Another group of commenters.
•however, opposed the imposition of a
formal testing requirement These
commenters argued that .mandatory
testing would place an inofdinate
burden on the regulated community -
without providing significant benefit for
human health and the environment. In
particular, the commenters claimed that
mandatory testing is unlikely to identify
wastes that were improperly
characterized as nonhazardous when
generators relied exclusively on their
knowledge. According to these
commenters, generators rely on their
knowledge only when the wastes they
produce are clearly hazardous or clearly
nonhazardous. Whenever uncertainty
exists, these commenters stated.
generators either declare their wastes
hazardous or perform appropriate tests.
The commenters emphasized that this
cautioned response results from
generators' liability for making incorrect
determinations, regardless of whether
they test their wastes. The commenters
concluded that requiring testing of all
wastes would deplete resources and
place a strain on limited laboratory
capacity.
The Agency recognizes that there are
many difficult issues related to the
imposition of a testing requirement, both
for the Toxicity Characteristic and the
other hazardous waste characteristics.
While the Agency believes that a testing
requirement could .improve the Agency's
enforcement tools, the Agency believes
that the current requirements for
hazardous waste determinations are not
ineffective because many generators do
have sufficient knowledge to make a
determination without a lest. The
Agency further believes that liability for
incorrect determinations provides a
strong incentive for not misclassifying
hazardous wastes as non-hazardous.
Although EPA thinks that the current
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11830 Federal Register / Vol. 55,-No. 61 / Thursday, March 29, 1990 / Rules and Regulations
system set forth in 40 GFR 262.11 is
effective, the Agency believes that
imposing a testing requirement does
have some merit, in that it could
increase the accuracy of determinations,
could clarify the responsibilities of
generators, and could facilitate
compliance monitoring.
The Agency will continue to evaluate
the comments on this issue as well as
explore other options for a testing
requirement At present, however, the
Agency is not yet ready to go forward
with a testing requirement based on any
of the options it has evaluated thus far.
Should the Agency decide that ah
appropriate approach is available, it will
propose and solicit comment upon the
details of that approach in a separate
mlemaking. In the meantime, the
Agency believes that the existing
determination requirement (as specified
at 40 CFR 282.11), as well as the liability
for incorrect determinations, is effective
and practical.
H. Applicability to Wastes Managed in
Surface Impoundments
As discussed above, in response to
the proposed TC, EPA received many
comments questioning the .validity of
applying the TC to wastes, including
wastewaters, likely to be managed in
surface impoundments. In response to
commenters* concerns, on May 18,1987,
EPA published a Supplemental Notice of
Proposed Rulemaking in the Federal
Register, which requested comments
and data on several issues related to the
regulation of wastes managed in surface
impoundments under the TC rule. The
Agency also requested comment
(assuming such an approach) on: (1) The
criteria to be used to determine whether
the surface impoundment scenario
should apply to a particular waste, (2)
the point at which concentration
measurements should be made (e.g., at
the point of generation or within the
impoundment), and (3) how multiple
surface impoundments should be
handled under the TC rule.
Comments received in response to the
notice concerning the surface
impoundment management scenario are
summarized and addressed in section
ni,A.2,c. Comments received in response
to the notice, which addressed sampling
point and multiple impoundment issues,
are discussed below.
1. Sampling Point
In the May 18,1987 notice, EPA
requested comments on whether
evaluations of wastes managed in
surface impoundments should be based
on measurements of the concentration in
the impoundment or at the inlet to the
impoundment. In response, some
commenters supported sampling at the
inlet to the impoundment and stated that
sampling the waste within the
impoundment is not only contrary to
Congressional intent, but conflicts with
EPA's own regulations that require the
determination of hazard to be made at
the point of generation.
Other conimenters, however, argued
that wastes should be sampled within
the impoundment or that the
impoundment effluent should be
sampled. Many of these commenters
, argued that measuring the
concentrations in the impoundment
more accurately represents the
concentrations of hazardous
constituents that pose a threat to ground
water. Some conimenters argued that
evaluation of hazard should be based on
impoundment effluent because
concentrations of the wastewaters
within the impoundment are
approximately the same as the
concentrations in the impoundment
effluent.
If the Agency were to allow persons
to make their determinations on the
waste in the impoundment, it would
raise questions that the Agency has not
yet evaluated completely nor taken
comment on. For example, in this
situation, should the Agency actually
require testing; if so, how often and
what should be tested? Would such a
result allow persons to land dispose of
wastes that (but for the point of hazard
determination) would be hazardous,
contrary to Congressional intent? Would
such a result allow persons to treat
wa'stes without a permit and thus be
inconsistent with Congressional intent?
EPA concedes that, for some activities
(e.g., closure), leachate quality may be
more appropriately assessed by
measuring concentrations at multiple
sites within the impoundment.
The current rules require that the
determination of whether a waste is
hazardous be made at the point of
generation (i.e., when the waste
becomes a solid waste). (A waste must
be a solid waste before it can be
classified as a hazardous waste under
RCRA.) EPA believes that determination
of the regulatory status of a waste at the
point of generation continues to be
appropriate, especially since the Agency
is not developing a separate
mismanagement scenario or set of
regulatory levels for wastewaters. To be
consistent with other hazardous waste
regulations and until the Agency
addresses the above questions, EPA is
retaining the existing approach of
requiring sampling at the point of
generation.
2. Multiple Surface Impoundments
In the May 18,1987 notice, EPA
requested comment on how multiple
surface impoundments or "treatment
trains" should be handled under the TC
rule. Some commenters favored
regulating all surface impoundments in a
treatment train as a single unit—if the
first impoundment treats a hazardous
waste, all impoundments,would be
required to comply with the RCRA
regulations for haziardous waste
treatment facilities. Other commenters,
however, suggested that each
impoundment should be regulated
individually. Still o ther commenters
stated that owners and operators should
be required to determine whether the
most upstream suriFace impoundment is
treating wastes thait exhibit the TC, but
they should only be required to evaluate
downstream impoundments if an
upstream impoundment exhibits the TC.
As discussed above,, the Agency has
decided not to develop a separate
regulatory scheme for surface
impoundments. Thus, the Agency will
continue to regulate all surface
impoundments as individual units and
will not pursue any of the other options
discussed by commenters. Currently,
under 40 CFR part 261, each surface
impoundment in a series of multiple
surface impoundments is regulated
separately. If a surface impoundment
receives or generates a hazardous
waste, the owner or operator of the
impoundment is required to comply with
the RCRA regulations governing
hazardous waste treatment, storage, and
disposal facilities. On .the other hand, if
a downstream impoundment is not
treating or generating a
characteristically hazardous waste and'
upstream units have not managed, listed
wastes, then the downstream unit is not
subject to RCRA subtitle C
requirements.
/. Relationship to Other RCRA
Regulations
1. Hazardous Waste Identification
Regulations
a. Hazardous Waste Listings. Under
the June 13,1986, proposal, the
hazardous waste listings in subpart D of
40 CFR part 261 would not be affected.
All the listings would remain in effect,
including those listings that were based
on the presence oi'TC constituents. It is
EPA's intention that the hazardous. j
waste listings would continue to ,.
complement the revised TC as they had
theEPTC.
A number of cotnmenters, however,
argued that the TC should supersede
certain hazardous waste listings. In
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Federal Eegister / Vol. 55; No-fl 7 Thursday. March 29. 1990 / Rules andJ^uiaUons 11831
particular, they suggested that the TC
should be the only basis for regulating
wastes that have been identified as
hazardous solely because of the
presence of a TC constituent Such an
approach, according to the commenters,
would establish a more rational basis
for identifying hazardous wastes.
Wastes failing the TC test would be
.•regulated as hazardous wastes, whether
or not they have previously been listed,
because they have demonstrated the
potential to pose a threat to human
health and the environment. Wastes
passing theTC test, in contrast, would
not be subject to subtitle C regulation.
The commenters claimed that, by
definition, if the extract from a waste
that was listed because of the presence
of a TC constituent does not contain the
constituent in £ concentration greater
than or equal to the regulatory level, the
waste can safely be managed at a
subtitle D facility.
EPA does not agree that the TC
revisions justify elimination of any of
the hazardous waste listings. The
Agency has consistently maintained that
individual waste streams may be listed
regardless of whether the waste is
defined as hazardous by the TC.
Exhibiting a characteristic can
constitute the basis for listing, a'waste.
In fact, prior to today's action,
approximately 25 listings were based on
the presence of metals or pesticides
covered by the EPTC.
There are a number of reasons for
continuing this approach. First, listed
wastes frequently contain hazardous
constituents other than the ones cited in
Appendix VII of 40 CFR part 261 as the
basis for the listings. It is for this reason
that Congress directed EPA, in
evaluating detisting.petitions, to
consider constituents other than those
for which the wastes were listed,
assuming that there is a reasonable
basis to believe that such constituents
might render the wastes hazardous (see
RCRA section 3001{f)j. In many cases,
the additional hazardous constituents
that are present in a waste may not be
on the list of TC constituents. The
listings may therefore serve to identify
wastes that pass the TC test but are
nevertheless hazardous. Removing
wastes from a hazardous waste listing
without an evaluation pf additional
constituents would appear to be
inconsistent with the intent of section
3001(fj.
Another reasop for retaining the
hazardous waste listings is that TC
constituents may continue to pose a
threat to human health and the
environment even when they are
present in concentrations lower than the
regulatory levels. The regulatory levels
have not been designed to address the
problems of phytbtoxicity, aquatic
loxicity, or bioaccumulatkm potential.
Moreover, they have not been designed
to identify the full range of wastes that
may be toxic to human beings. Instead,
the characteristic levels have been
established at concentrations where
there is a high degree of certainty that
any wastes with constituents at levels
equal to or exceeding the regulatory
levels pose a potential threat to human
'health. Individual wastes may continue
to be hazardous, despite the fact that •
they may contain TC constituents in
concentrations below the regulatory
levels. This is particularly true for •
wastes that have the potential to be
exposed to more aggressive leaching
conditions than those modeled in the
TCLP. As a result, EPA believes that
wastes previously listed as hazardous
should continue to be, considered
hazardous, whether or not they exhibit
the characteristic.
b, "Mixture"and "DerivedFrom"
.Rules, Because the TC will not
supersede the listings for hazardous
wastes, it also will not affect the
regulatory status of wastes that are
hazardous by virtue of the "mixture"
rule of 40 CFR 262.3(a){2)(iv) or the
'.'derived from" rule of 40 CFR 261.3{c).
The "mixture" rule provides that any
mixture of a listed hazardous waste and
a solid waste is itself a RCRA hazardous
waste.3 The "derived from" rule states
that any waste derived from the
treatment, storage, or disposal of a listed
hazardous waste is hazardous.
. Several commenters contended that
the current regulatory scheme
encompasses wastes that contain de
minimi's quantities of teachable organic
chemicals. The commenters
acknowledged that mixtures and
treatment residues posing insignificant ,
threats to human health and the
environment may be excluded from
regulation through the delisting process.
However, they claimed that delisting is
unduly expensive, time-consuming, and,
in some cases, impractical.. The
commenters suggested as an alternative
that mixtures and treatment residues
from listed wastes containing TCLP
constituents not be considered
hazardous unless they fail the TC test
They contended that this approach
would adequately protect human health
and the environment Moreover, it
3 The exception to this rule is a mixture of solid
waste and a waste that is listed solely because it
exhibits a characteristic of hazardous waste. If *uch
a mixture does not exhibit any characteristic of
hazardous waste, the mixture is not defined as
hazardous (40 CFR Z81-3(e)(2)f:M)].
would be "self-implementing," in the
sense that it would eliminate the need
for the current process of petitions arid
Agency review for delisting.
EPA recognizes that the "mixture"
and "derived from" rules may create
some inequities by including wastes that
contain very small amounts of
hazardous wastes that have been mixed
so as to render them nonhazardous.
However, the Agency has consistently
maintained that the mixture and derived
from rules are an,appropriate regulatory
approach for dealing with waste
mixtures and treatment residues*
When the rules were promulgated in
1980, EPA stated that it was essential to
regulate waste mixtures to prevent
generators from evading subtitle C
requirements by simply.co-mingling
listed wastes with nonhazardous
wastes. The Agency also determined '
that because of the infinite potential
combinations oflisted wastes and other
wastes, it was unable at that time to
devise any workable, broadly applicable
formula that was capable of
distinguishing between hazardous and
nonhazardous mixtures. The Agency
acknowledged that the "mixture" rule
might be overly broad, but noted that
generators could avoid any inequities
either by segregating their wastes or by
obtaining a waste-specific exclusion
under the delisting program (see 4S FR
33095, May 19,1980).
EPA also believed that it was
important to regulate wastes from the
treatment, storage, or disposal oflisted
hazardous wastes on the basis that
these "derived from" wastes might
themselves be hazardous. Once again,
however, the Agency found that because
of the large number of listed wastes and
treatment processes (some of which
introduce new hazardous constituents
into the treatment residues), it was
unable to prescribe standards that could
properly distinguish between hazardous
and nonhazardous residues. (It should
be noted that the definition of treatment
is not confined'tb rendering a waste
non-hazardous, but also, includes any
method designed to change the nature of
a waste to render the waste [I] less
hazardous; (2) safer to transport, store,
or dispose; (3) amenable for recovery; or
(4) reduced in volume (see 40 CFR
260.10).} Therefore, the Agency
concluded that wastes-generated during
the treatment of listed wastes should be
presumed to be hazardous. Delisting
was provided as the mechanism for
excluding these wastes from subtitle C
regulation (45 FR 33098., May 19.1980}.
EPA is sympathetic to the
commenters' concerns regarding use of
delisting to exclude wastes that are
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11832 Federal Register / Vol. 55, No. 61 / Thursday. March 29, 1990 / Rules and Regulations
hazardous under the "mixture" and
"derived from" rules. The Agency does
not believe, however, that the
Alternative suggested by the
commenters (i.e., relying on the TC to
regulate mixtures and treatment
residues) would adequately protect
human health and the environment. As
noted above, wastes that pass the
characteristic test may nevertheless be
hazardous, either because they contain
listed constituents at concentrations
below the TC regulatory levels but at
levels and under circumstances that
nevertheless render the waste
hazardous or because they contain
hazardous constituents that are not
covered by the TC rule. As noted above,
the TC regulatory levels are not
threshold levels defining all hazardous
waste, but are levels that are set to
clearly define hazardous waste. Wastes
containing constituents falling below
these levels may still present a hazard in
more limited situations.
Nevertheless, the Agency recognizes
that some inequities may result by the
application of the "mixture" and
"derived from" rules to certain dilute
listed wastes. The Agency therefore is
considering proposing an amendment to
the definition of hazardous waste which
would establish self-implementing de
'minimi's exemption levels for hazardous
constituents found in listed wastes.
Listed wastes that meet these exemption
levels would no longer be listed
hazardous wastes and thus would not
need to be managed as hazardous
wastes unless they exhibit a hazardous
waste characteristic,
c. Mixture Rule Exemption. The
mixture rule under 40 CFR 281.3(a)(2)(iv)
provides an exemption from RCRA
subtitle C regulation for mixtures of
wastewaters and certain listed spent
solvents. The mixture rule exemption is
applicable only if the maximum weekly
usage of the solvents (other than
solvents that can be demonstrated not
to be discharged to wastewater) divided
by the average weekly flow of
wastewater does not exceed specified
values. The mixture rule exemption does
not apply to wastewaters that exhibit a
characteristic of hazardous waste or to
wastewaters that contain listed
hazardous wastes not specified in the
mixture rule exemption.
A number of commenters claimed that
the proposed TC conflicts with the
mixture rule exemption". The
.commenters noted that the mixjture rule
exemption levels are higher than .the
corresponding TC regulatory levels for
solvent constituents. Because of this .
difference in regulatory levels, the
commenters stated that the proposed TC
rule will bring large quantities of
currently exempted wastewaters into
the hazardous waste management
system. In effect, the commenters argued
that the TC rule will revoke the mixture
rule exemption. Commenters
disapproved of this result, stating that
the mixture rule exemption was
promulgated in recognition that small
amounts of certain spent solvents are
often most efficiently managed by being
discharged to a plant's wastewater
treatment system and that this method
of management does not pose risks to
human health and the environment.
EPA acknowledges that the TC rule
may bring some currently exempted
wastewaters into the subtitle C
regulatory system; however, the mixture
rule exemption is an exemption from the
hazardous waste listings, not the
characteristics. Thus, there is no
inconsistency between this rule, and the
mixture rule exemption. In addition, it
should be noted that the TC regulatory
levels are based on state-of-the-art
lexicological data and risk assessment
methodologies. Consequently, EPA
believes that the TC regulatory levels
are the best measures available to
identify wastewater mixtures that pose
a threat to human health and the
environment. In contrast, the mixture
rule exemption levels are based upon
less current risk information.
Even though some wastewaters
presently covered by the mixture rule
exemption will become hazardous
wastes as a result pf the TC rule, EPA .
believes that the exemption will
continue to serve an important purpose
by ensuring that mixtures of
wastewaters and certain listed spent
solvents will not be considered
hazardous unless they exhibit a
•characteristic of hazardous waste. To
• clarify the mixture rule exemption and
make it more consistent with current
risk information, EPA is considering
proposing in the future that the mixture
rule exemption levels be reduced so that
they are equivalent to the TC regulatory
levels.
d Delisting. While the June 13,1986
proposal did not specifically address the
.effect that the TC might have on the,
hazardous'waste delisting program
under 40 GFR 260.22, a number of
comments were received claiming that
the TC rule would be inconsistent with
existing EPA policies regarding case-by-
case exclusions. In the August 1,1988
proposal, however, the Agency solicited.
comment on the use of the EPACML
model in the delisting program.
The commenfers noted that each
major element of the delisting program
js different from the corresponding.
element in the original TC proposal. For
example, the chronic toxicity reference
levels that are used, to establish "no
hazard" levels under the delisting "
program appear to differ from the levels
that were used to establish the proposed
TC regulatory standards. In addition, the
delisting program uses (as appropriate)
a different ground water transport:
model (i.e., the Vertical and Horizontal
Spread (VHS) Model), which generates '
generic DAFs rather than compound-
specific factors. Finally, the delisting
program employs (as appropriate) the
Organic Leachate Model (OLM) rather
than the EP or the TCLP to determine
the degree ,to which various organic
constituents are likely to leach from
solid wastes. The commenters urged the
Agency to use the name reference levels,
DAFs, and leaching procedures in both
the characteristic and delisting
programs. A few commenters expressed
a particular preference for adopting the
delisting elements as part of the revised
TC,
There were a number of differences
between the various elements of the
proposed TC and the corresponding
elements in the delisting program.
However, regarding Chronic Toxicity
Reference Levels, the only difference
between the levels used in the delisting
program and those in the TC final rule is
the use of different risk levels for the (
carcinogens (i.e., delisting uses a more
conservative: risk factor of 10~ 6 for
carcinogens, compared to the use of a
10~s risk factor in the TC rule). Many of
the differences'between the chronic
toxicity reference levels used in the TG
rule and those in the delisting program
have been eliminated as a result of
decisions concerning risk levels and
apportionment. Furthermore, th.e health-
based levels used in the delisting
program and in the TC rule have been
updated to incorporate recent Agency
evaluations (see 53 FR18024).
EPA believes that the risk factors
being used for each program are
appropriate, and does not think that risk
levels used to set regulatory levels
should necessarily be' the same in the
two programs because each serves a
separate purpose. Delisting evaluates
the hazard posed Iby specific individual
wasitestreams thallhave been listed as
hazardous. Characteristics identify
broad classes of clearly hazardous-
wastes; specific wastes that may pose a
substantial identified hasard in a lower
risk range may be listed as hazardous.
As discussed below, EPA believes it is
appropriate that the delisting program is,
in certain cases, more stringent than the
characteristic'proigram. ' '
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Federal Register / Vol. 55. No. 61 / Thursday. March 29. 1990 /Rules and Regulations 11833
A number of commenters focused 'on
the overall stringency of the
characteristic and delisting programs. In
particular, the commenters stated that
the proposed TC regulatory levels were
-sometimes greater than and sometimes
less than the concentration standards-
used by the Agency's delisting program
in determining when listed wastes may
properly be managed in subtitle D
•facilities. Most of the commenters
argued that EPA, in the interest of
consistency, should adopt the same
concentration standards under the
characteristic and delisting programs.
Other commenters, however, urged the
Agency to establish higher
concentration standards under the
revised characteristic. The latter group
of commenters noted that characteristics
are designed to identify broad classes of
solid wastes that are "clearly"
hazardous, while listings are designed to
identify, wastes that may not exhibit a
characteristic, yet are nevertheless
hazardous. The commenters concluded
that, in light of the different functions of
listings and characteristics, it should be
more difficult for a waste to pass the
delisting standards (i.e., to be eligible for
delisting) than for the same waste to
pass the characteristic test.
•EPA does not agree with those
commenters who argued that the
Agency must use the same
concentration standards in the
characteristic and delisting programs or,
that the concentration standards for
characteristics must be higher than
those for delisting. These programs have
very different purposes. While
hazardous waste characteristic levels
are those equal to or above which a
waste is clearly .hazardous due to a
particular property, delisting levels are
those below which a waste is not
hazardous. Thus, it is reasonable that
these two levels may or may not
coincide. Delisting decisions are based
. on an extensive evaluation of a
particular waste which requires specific
information on the waste. The
characteristics approach to defining a
hazardous waste is much'more broad.
Only one mismanagement scenario is
used and it is based on "reasonable
worse-case" assumptions resulting in a
"generic" regulatory level to be applied
to all solid waste. And, of course,
section 260.22 of the RCRA regulations
specifies that a waste may not be
delisted if it exhibits a characteristic of
hazardous waste (e.g:, the characteristic
of EP toxicity). Thus, the delisting
program could never be less .stringent
than the characteristic program.
In regard to the use of different
models in the delisting and
characteristic programs, in the August!,
1988 Federal Register notice, the Agency
specifically solicited comment on the
use Of the Toxicity Characteristics
model (EPACML) in place of the model
currently used in the delisfing program
(the VHS model). All of the commenters
supported the use of EPACML instead of
the VHS model in the delisting program,
although one commenter supported this
only if it would not add complexity and
thereby increase the time required for
delisting petition evaluation. Another
commenter stated that the EPACML
model should be used in the delisting
program but that petition evaluations
should not be restricted to the use of any
single specific model. Finally, several of
the commenters stated that the Agency'
should present details as to how the
EPACML model would be used for
delisting in a separate Federal Register
notice.
In response to these comments, the
Agency will use the EPACML model and
the TCLP in the delisting program. Also,
as suggested, the Agency will explain
how the model and the TCLP will be
used in a future Federal Register notice.
- A few commenters expressed concern
about the applicability of the TC to
wastes that have previously been
delisted. The commenters argued that
once EPA has ruled {through the waste-
specific delisting process) that a
particular waste stream poses no threat
to human health and the environment.
the Agency should be barred from using
a generic rule to declare the same waste
as being "clearly" hazardous. One
commenter claimed that it would be
especially unfair to alter the regulatory
status of a waste stream after the person
managing it has been granted an
exclusion and has acted in reliance on
that exclusion (e.g., by changing the
production process or waste
management practices).
EPA has consistently maintained that
wastes "excluded" from subtitle C
regulation under the delisting program
may nevertheless be hazardous if they
exhibit a characteristic of hazardous
waste (see 40 CFR 260.22}. While the TC
rule will apply to previously delisted
waste, EPA does not, in general, expect
that such wastes will become hazardous
because of application of the revised
TC. The Agency believes that, because
delisting levels-are more stringent than
the final TC levels, the impact of the TC
rule on previously delisted wastes will
be minimal. Nevertheless, if a previously
delisted waste exhibits the TC, it will
again be subject to subtitle C
requirements (i.e., delisted wastes are
treated no differently than any other
solid waste).
2. Land Disposal Restrictions
a. Risk Levels and Frequency Interval
The approach used to develop
regulatory levels in the proposed TC
rule was similar to the original approach
suggested for developing'treatment '
standards in the proposed Land
Disposal Restrictions (LDR) rule (51 FR
1602, January 14,1986). Both proposals
began with health-based concentration
thresholds at the point of exposure and
used subsurface fate and transport
models to back-calculate allowable
constituent concentrations in the
leachate. In the June 13,1986 TC
proposal, the Agency requested
comments on whether the risk levels
and cumulative frequency level used in
the TC should be the same as those used
to develop the treatment standards in
.the proposed LDR rule.
Several commenters supported the use
of different risk levels and cumulative
frequency levels in the two proposals.
These commenters stressed that
different statutory mandates for the two
rules and the entirely different functions
of the TC regulatory levels and the LDR
treatment standards warranted different
approaches. However, other
commenters contended that the
frequency level and risk levels in the.TC
rule should be the same as or more
stringent than those used in the LDR
proposal. Some of these commenters
argued that the more stringent risk
levels-and frequency level in the LDR
proposal provided a more appropriate
degree of protection for human health
and the environment than the
corresponding levels and frequency
interval in the TC proposal.
The issue of consistency of risk levels
and frequency level for the TC and the
LDR program is now moot. The LDR
final rule {51 FR 40572, November 7,
1986) abandoned the use of screening
levels based on risk methodology and
subsurface fate and transport modeling,
and promulgated an approach to
establishing treatment standards based
entirely on technology-based standards
expressed as Best Demonstrated
Available Technology (BOAT). Today's
rule continues to be based upon health-
based concentration levels and dilution/
attenuation factors, the values for which
are based upon the predictions of a
subsurface fate and transport model.
b. Treatment Standards for TC
Wastes. Under RCRA section 3004{g){4);
EPA is required to make an LDR
determination for all TC wastes within 6
months of today's action, as discussed
in .the following section. Several
commenters were concerned that the
LDR treatment standards that will
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11834 FederalRegister/ Vol.55,No.61 / Tjiresday.March29,1990/Rules andRegulations^
eventually be established for the TC
wastes may be inconsistent with TC
regulatory levels. Some of these
commenters noted that the proposed
LDR treatment standards for listed spent
solvents were in many cases lower than
the proposed TC regulatory levels for
the Identical constituents in unlisted
characteristic wastes. The commenters
feared that if LDR treatment standards
are applied to unlisted TC wastes in the
same manner as they are applied to ,
similar listed wastes, the characteristic
wastes may require treatment to below
the TC level before subtitle C land
disposal is permissible. This means that
unlisted wastes no longer exhibiting the
TC must continue to be managed as
hazardous wastes. Some commenters
who voiced concerns over potential
differences between TC regulatory
levels and LDR treatment standards
suggested,that there should be a clear
continuum of regulatory levels, with the
higher standards being those that deem
a waste hazardous in the first place (i.e.,
the TC regulatory levels).
Wastes deemed hazardous under the
TC will not immediately become subject
to the LDR program on the effective date
of the TC rule, except perhaps by
operation of the California List
restrictions (i.e., halogenated organic
compounds are subject to the LDR if
they exhibit a characteristic, see 52 FR
25770, July 8,1987). However, the
Agency has not yetdetermined whether
the existing LDR California List
restrictions should be applicable to
newly identified TC wastes. The Agency
specifically requested comment on the
appropriateness of applying the
California List prohibitions to newly
identified hazardous wastes in the
November 22,1989 proposed rule for the
"Third Third" of scheduled wastes (54
FR 48499). The Agency will fully address
this issue as part of the "Third Third"
final rule.
Since the Agency is not today
proposing LDR treatment standards for
the TC wastes, the Agency believes that
it is more appropriate to address these
comments-when the LDR treatment
standards are proposed. However, in
response to comments that proposed
treatment standards for listed solvents
were lower than proposed TC levels, the
Agency would like to point out that the
treatment standards for TC wastes will
not necessarily be the same as the
corresponding LDR treatment standards
for spent solvents. Indeed, if the TC
wastes belong to a different treatability
group, one can expect that the treatment
standards will be different
c. Schedule for LDR Determinations.
For wastes already listed or identified at
the time of enactment of HSWA, the
Agency must make LDR determinations
according to the schedule set forth in
RCRA section 3b04(g)(4). If EPA fails to
make the determinations by the
established schedule, the wastes are
automatically subject to the land
disposal restrictions on the .scheduled
date. EPA must also make LDR
determinations for all wastes that are
identified or listed as hazardous after
November 1984 (when HSWA was
enacted) within six months after the
wastes are identified or listed.
. On November 22,1989 (54 FR 48372),
EPA proposed treatment standards for
those wastes that exhibit the EPTC, as
well as any of 'the other characteristics.
Upon the effective date of today's rule,
the TC will include the 14 EPTC
constituents in addition to the 25
organics, and the TCLP will replace the
EP.'EPA proposed that the BOAT levels
for wastes that exhibit the EPTC for the
14 constituents remain the same when
the TC becomes effective. By May 8,
1990 the Agency will establish the final
BOAT levels for the 14 constituent
currently identified by the EPTC. Newly
identified TC wastes are subject to the
six-month listing deadline. However,
wastes are not automatically prohibited
from land disposal if EPA fails to make
this required determination within six
months.
Some commenters argued that the six-
month deadline would accelerate the
LDR determinations for listed wastes
that contain TC constituents. For
example, some commercial chemical
products are currently scheduled to be
reviewed by May 8,1990 (51 FR 19300,
May 28,1986). However, these wastes
also may exhibit the TC. Commenters
were concerned-that these wastes may
be subject to the six-month deadline and
claimed that this would effectively
accelerate the determinations in a
manner that would be contrary to
Congressional intent.
Wastes that are newly identified as
hazardous by today's rule will be
subject to the six-month deadline for
LDR determinations. However, even if
EPA were to complete LDR
determinations for TC wastes before
May, 1990, the Agency disagrees with
commenters that this has the potential
to accelerate the determinations in a
manner that would be contrary to
Congressional intent. The dates set forth
in RCRA section 3004(g)(4) are deadlines
by which EPA must make LDR
determinations or the wastes are
automatically restricted from land
disposal. EPA is in no way prevented or
discouraged by the statute from making
LDR determinations before any of its
deadlines (RCRA section 3004(g)(5),
"Not later than * * *"). Indeed, other
determinations are being made ahead of
schedule; the final rule for restricting
"second third" wastes includes
treatment standards and prohibitions for
.some "third third" wastes (54 FR 26594).
3. RCRA Corrective Aption and Closure
Requirements
Today's rule will have no direct effect
on either the action levels of RCRA
corrective action or the cleanup
standards of RCRA closure
requirements. However, to the extent
that the TC bring!! more facilities under
the RCRA program as hazardous waste
management facilities, additional
facilities will be newly subject to the
subtitle C corrective action and closure
requirements.
Although the corrective action
program under subtitle C addresses
remediation of releases of hazardous
constituents from waste at facilities
subject to RCRA permitting, the TC
levels will be neither action levels (i.e.,
concentrations that, if exceeded, signal
the need for corrective action) nor
cleanup standards. Rather, corrective
action, as a process, encompasses
trigger levels and cleanup standards that
are developed from site-specific
information gathered during the
investigatory and evaluative phases of
the process (i.e., the RCRA Facility
Investigation and the Corrective
Measures Study).
Thus, the levels or concentrations
associated with today's TC rule are
largely independent from levels
associated with corrective action.
Similarly, the closure requirements are
unaffected by today's rule. The TC is not
used to determine whether a facility has
met the requirements for clean closure.
However, it must be noted that solid
wastes generated as a result of
remediation of releases or in pursuance
of closure requirements that exhibit the
TC must be handled as a hazardous
waste. :
4. Minimum Technology Requirements
a. Applicability. HSWA added section
3004(o) to RCRA which imposes
minimum technology requirements on
owners and operators of certain landfills
and surface impoundments seeking
permits. HSWA also added a new
section 3015 imposing similar
: requirements on certain interim status
waste piles, landfills, and surface
impoundments. Finally, HSWA section
3005(j) requires surface impoundments
to be retrofitted to meet minimum
technology requirements. EPA codified
the statutpry language in the Agency's
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Codification Rale promulgated on July
.25,1985 (50 FR 28705). Facilities that will
face new RCRA regulation following the
promulgation of the TC will need to
comply with the minimum technology
requirements in order to remain in
operation.'
b. Scope of Minimum Technology
Requirements—1. Permitted Facilities.
Section 3004{o)(l)(A) requires that after
November 8,1984, certain landfills and
surface impoundments must meet
minimum technology requirements. The
minimum technology requirements for
landfills and surface impoundments
appear in 40 CFR 264.301(c) and
264.221{c), respectively. They require the
owner or operator of each new unit and
each replacement unit or lateral
expansion of an existing unit to install
two or more liners and a le'achate
collection system between and, for
landfills, above the liners.
2. Interim Status Facilities. Section
3015 of RCRA requires that certain
waste piles, landfills, and surface
impoundments meet minimum
technology requirements. The minimum
technology requirements for interim
status waste piles, landfills, and surface
impoundments appear in 40 CFR 265.254,
265.301, and 265.221, respectively. They
require that the owner or operator of
each new unit, replacement of an
existing unit, or lateral expansion of an
existing unit that is within the area
.identified in the part A permit
application install liners and a leachate
collection system or equivalent
protection. Existing surface
impoundments fie., surface
impoundments regulated under subtitle
G prior to November 8,1984} had to be
retrofitted to meet the minimum
technology requirements by November
8,1988.
c. Compliance with Minimum
Technology Requirements. Facilities or
units newly regulated as a result of the
TC will have to meet the minimum
technology requirements of sections
3004(o) and 3015 if and when they add a
new unit, replace an existing unit, or
laterally expand an existing unit.
Surface impoundments must comply
with the retrofitting requirement in
section 3005(j)(6)(A), which requires the
owner or operator of a newly-regulated
surface impoundment to retrofit that
impoundment 4 years from the date of
promulgation of the additional listings or
characteristics, that made it subject to
regulation. Thus, surface impoundments
that become regulated under subtitle C
because of the TC will need to meet the
minimum technology requirements on
March 29,1994. (However, retrofitting
may be expedited due to the minimum
technology requirements imposed under
the capacity variance for land disposal
under section 3004.) This extension
applies only to those impoundments that
contain solely the newly listed/
characteristic wastes. Any
impoundments that already contained
listed/characteristic wastes currently
are subject to RCRA regulations,
including the minimum technology
requirements. Other existing land
disposal units (besides surface
impoundments) that already contained
wastes that exhibit the TC will not
require retrofitting unless they are
expanded or are replacement units.
5. RCRA Subtitle D (Solid Wastes)
a. Municipal Waste Combustion Ash.
Several commenters requested that ash
from municipal waste combustion
(MWC) units be exempt from regulation
under the TC. Many of these
commenters argued that the regulation
of MWC ash would be in direct conflict
with RCRA section 3001(i), which
provides that resource recovery
facilities engaging in MWC "shall not be
deemed to be treating, storing, disposing
of, or otherwise managing hazardous
wastes." Other commenters indicated
that the high costs associated with
subtitle C regulation would discourage
the recovery of energy values from
MSW. They claimed that this result
would run counter to the clear
Congressional intent to encourage
resource recovery as a beneficial
alternative to the landfilling of MSW.
EPA articulated its position on the
scope of section 3001ft) when the
Agency codified the 1984 HSWA (see 50
FR 28725, July 15,1985). However, two
recent Court decisions have rejected
EPA's 1985 interpretation. EDFv. City of
Chicago, No. 88C769 (N.D. HI.) (slip op.
Nov. 29,1989) and EDFv. Wheelabrator
Technologies Inc., No. 88Civ.0560 (S.D.
N.Y.) (slip op. Nov. 21,1989). The
Agency is considering the appropriate
response to these two decisions.
b. Impact on Wastes Excluded from
Subtitle C Regulation. Another group of
commenters asked for assurances that
the TC rule would not affect the existing
exclusions for specific wastes under 40
CFR 261.4{b). One eommenter expressed
particular concern about the exclusion
for mixtures of household and other
nonhazardous solid wastes. Another
eommenter raised questions about
applying the-TC to wastes that are
usually considered to be non-hazardous
solid wastes. Other commenters focused
on the exemptions for "special wastes,"
primarily mining and mineral processing
wastes and oil and gas production
wastes. A utility company consortium
addressed the exemption for wood
treated with arsenic, commonly used as
a fungicide for utility poles. The
eommenter noted that cresols and
pentachlorophenol, also Used as
fungicides for wood, are proposed as TC
constituents; the eommenter asserted
that the exemption for arsenic-treated
wood should be extended to creosote-
and pentachlorophenol-treated wood as
well.
The TC rule will not apply to wastes
that are already excluded from subtitle
C regulation tinder § 281.4{b). These
wastes will continue to be exempt from
regulation as hazardous wastes, even if
they would exhibit the TC. Likewise, the
TC rule does not add any exclusions to
the applicability of previously
promulgated hazardous waste
characteristics. With respect to the issue
of creosote- and pentachlorophenol-
treated wood, EPA does not at this time
intend to expand the list of exemptions
under § 261.4(b) to include these wastes.
This is discussed further in section
It should be noted* however, that the
special waste exclusions are currently
being reevaluated in accordance with
the criteria and procedures mandated by
Congress. After completing the studies
required by RCRA section 8002, EPA
may determine that one or more special
wastes should be regulated under RCRA
subtitle C (see RCRA section 3001(b)).
Such wastes would then be listed or the
generators required to determine
whether the wastes exhibit a hazardous
waste characteristic.
A few commenters argued that even if
special wastes are brought into the
subtitle C system, they should not be
subject to the TC. These' commenters
claimed that codisposal of special
wastes with MSW is implausible
because special wastes, by definition,
are generated in very large quantities.
The commenters recommended that EPA
develop a separate mismanagement'
scenario and leaching procedure for
special wastes.
At this time, the Agency cannot agree
that the TC should not be applicable to
special wastes; rather, the applicability
to these wastes will be determined on a
case-by-case basis. If EPA makes a
determination that any special wastes
should be regulated under RCRA ,
subtitle C, the Agency will at that time
make a separate determination
concerning the applicability of the.TC to
such wastes.
6. RCRA Subtitle I (Underground
Storage Tanks)
a. Scope of the Underground Storage •
TankProgram. Subtitle I of RCRA
provides for the establishment of a
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11836 Federal Register / Vol. 55, No. 61 / Thursday, March 29, 1990 /Rules and Regulations
regulatory program for underground
storage tanks containing "regulated
substances." Regulated substances are
defined under RCRA section 9001(2) as
(1) petroleum and (2) hazardous
substances listed under section 101(14)
of the Comprehensive Environmental
Response, Compensation, and Liability
Act (CERCLA or Superfund), excluding
hazardous wastes regulated under
subtitle C of RCRA.
Except as discussed below, today's
action will change the regulatory status
of TC wastes that were previously
subject to RCRA subtitle I. Because
these wastes will be RCRA hazardous
wastes, they are excluded from
regulation under subtitle I (see 40 CFR
part 280,10{b)(l)). For this reason,
underground storage tanks that contain
TC wastes will be subject to the subtitle
C tank requirements rather than those
promulgated under subtitle I.
b. Deferral for Petroleum-
Contaminated Media and Debris
Subject to Part 280 Corrective Action
Requirements, As part of its
underground storage tank (UST)
program, the Agency has recently
promulgated regulations which address
releases from USTs containing
petroleum (see 53 FR 37082, September
23,1988 and S3 FR 43322, October 26,
1988). Among other requirements, these,
rules require petroleum UST owners and
operators to install leak detection, to
report leaks from their tanks and piping,
to undertake corrective action to
address such releases, and to
demonstrate financial assurance for
corrective action and third parry
liability resulting from such releases.
These requirements started going into
effect in December, 1988, and the "
Agency estimates that over the next few
years more than 300,000 petroleum UST
releases, will be discovered and be
subject to the subtitle I corrective action
requirements. In addition, the Agency
has, through cooperative agreements,
provided funding to states from the
Leaking Underground Storage Tank
(LUST) Trust Fund under RCRA to
undertake the necessary response
actions where petroleum UST owners
and operators are unable or unwilling to
do so. Hundreds of petroleum UST
cleanups have been initiated to date
under this program.
As noted in the preamble to the final
UST rules, due tq the large regulated
community affected by the UST
regulations, the UST program is based
oh self-implementing requirements and
Is highly dependent upon voluntary
compliance to attain the environmental
perfomiance'objec'tives of the program.
However, because petroleum contains
several of the hazardous constituents for
which regulatory levels are being
established today (e.g., benzene) some
of the petroleum-contaminated media
and debris may exhibit the Toxicity
Characteristic under today's rule. While
the amount and type of media and
debris that may exhibit the
characteristic at any particular UST site
will depend upon the petroleum product,
soil type, arid the size of the release, it is
likely that many sites where petroleum
UST releases have occurred will contain
some media that exhibits the Toxicity
Characteristic. The management of any
such media and debris would-be subject
to subtitle C requirements for hazardous
waste management.
The Agency has insufficient
information concerning the full impact of
this rule on UST cleanups, but the
information available to date suggests
that the impact may be severe in terms
of the administrative feasibility of both
the subtitle'C and subtitle I programs.
Thus, the Agency has decided to defer a
final decision on the application of the
TC to media arid debris contaminated
with petroleum from USTs subject to the
part 280 requirements. The application
of today's rule to these cleanups will be
delayed while the Agency evaluates the
extent and nature of this impact and
alternative administrative mechanisms
for implementing the UST cleanups in
accordance with subtitle C
requirements; the Agency believes that
the UST regulations governing cleanups
at these sites will be adequate in the
interim to protect human health and the
environment.
The deferral of a final decision
concerning application of this rule to
UST cleanups is necessary for several
reasons. First, while the actual number
of sites and amount of media and debris
at each site that would exhibit the
toxicity charagteristic under today's rule
is unclear, based on a preliminary
assessment, .the number and amount
could be extremely high. As noted
above, EPA expebts hundreds of
thousands of UST releases to b'e
uncovered in the next few years.
Subjectuig'each of these sites to subtitle
Grequiremen.t8 could overwhelm the
hazardous waste permitting program
and the capacity'of existing hazardous
waste treatment, storage, and disposal
facilities. Imposition of the subtitle C
requirements is also likely to delay
cleanups significantly and severely
discourage the self-monitoring, and
voluntary reporting essential to1
implementation of the UST program.
Moreover, the UST cleanup activities
involving the most contaminated media
and debris are also likely to involve free
product recovery. Free.product recovery
would not be subject to subtitle C
, requirements because the material being
recovered is not a waste.
Because of the uncertainties of the
impacts on the UST cleanups as a result
of this rule, including the amount of
contaminated media that would become
hazardous waste arid the type of
management feasible and appropriate
for such Waste (i.ei./on-site treatment,
off-site disposal), EPA cannot determine
whether the application of this rule to
these cleanups will have the severe
consequences on Implementation of
these RCRA programs that preliminary
information suggests. Also, because this
issue did not come to .the Agency's
attention until late in the development
of this rulemakinj!, the Agency has not
had an opportunity to obtain public
input on this issue, the implications of
the subtitle C requirements when
applied to UST cleanups, or any
alternative regulatory mechanisms to
make feasible the implementation of.
UST cleanups while meeting subtitle C
hazardous waste requirements. Thus,
the Agency believes that further.
evaluation of the impacts of applying the
TC to soils and ground water .
contaminated by petroleum from USTs
and subject to the subtitle I program is
necessary in order to determine, whether
an exemption for such materials is
warrantedpr whother additional
regulatory or administrative changes ,
can or should be made in order to make
the application oi: the TC to UST
cleanups feasible.
In order to make a final decision
concerning the applicability, of this rule
to UST sites, the Agency intends to
undertake several activities. First, the
Agency will attempt to more specifically
define the impact of the TC through
studies of petroleum UST sites,'focusing
upon the potential hazard from these
sites. More specifically, the Agency will
study the characteristics of UST sites
(number of UST sites by media type,
volumes of media and debris typically
removed, fraction of this media and
debris that exhibits the TC, if any, etc.),
current'practices and requirements for
management of these media and debris;
'and how contaminated media and
debris from theso sites are managed
under the new subtitle I state programs.
As currently envisioned, these studies
will include: (1) A survey of tank
vendors, contractors, and .others
knowledgeable about. UST site
characteristics and contaminated media
and debris management practices; (2) a
survey of current state and .local
programs; and (3> a sampling program
conducted in conjunction with one or
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more selected states. The Agency also
plans to evaluate the impact that
subtitle C managemeitf of petroleum-
conjaminated media and debris from
USTs would have on the Agency's and
states" hazardous waste management
programs. In addition, the inclusion of
these media and debris in the subtitle C
management system will be evaluated in
comparison to the available capacity.for
commercial hazardous waste treatment,
storage, and disposal.
Second, the Agency wil! evaluate
whether and how the subtitle C
requirements can be feasibly
: implemented for UST cleanups. This
evaluation will include an investigation
of regulatory streamlining, phased
compliance, or other administrative
changes to increase the feasibility of
, implementing UST cleanups in
accordance with subtitle C
requirements. As part of this effort and
the larger issue of the-application of
subtitle C requirements to contaminated
media, EPA intends to convene a public
forum to discuss the relationship
between subtitle C and subtitle I
requirements, the impacts of the subtitle
C program on UST cleanups, and how
the subtitle C requirements can feasibly
be applied to the UST cleanups.
EPA requests data and comment from
the public on these issues. Upon
completion of the evaluations described
above, EPA will determine whether to
retain the temporary exemption for UST
cleanups provided in this rale or to
remove'the exemption and make the TC
fully applicable to corrective actions
under subtitle L
7. RCRA Section 3Q04(n) Air Regulations
In HSWA, Congress directed EPA to
"* •* * promulgate such regulations for
the monitoring and control of air
emissions at hazardous waste treatment,
storage, and disposal facilities, including
but not limited to open tanks, surface
impoundments, and landfills, as may be
necessary to protect human health and
the environment." This provision was
added as section 3004(n) of RCRA. In
response, the Agency proposed the first
of a multi-phased set of air regulations
for TSDFs on February 5,1987 (53 PR
3748). This first phase is intended to
apply to equipment that would be used
to treat wastes that: would first be
subject to the Land Disposal
Restrictions (LDR) standards to ensure
that the LDR treatment did not result in
cross-media transfer of hazardous
constituents to the air (see IIJ.I.2., above,
for a discussion of the LDR program).
This first phase is to be followed by
proposals for more comprehensive air
regulations for TSDFs. Once these air
standards are promulgated, they are
expected to apply to many of the wastes
newly regulated by today's rule.
The February 5,1987 proposal would
limit air emissions of organics as a class
from certain treatment units. The
proposed rule would apply to specified
equipment that contains or is in contact
with certain hazardous wastes, which
are identified based upon their potential
to emit organics. The proposed
standards contain two major features.
First, a 95% reduction in process
emissions from units distilling or
stripping {air or steam) organic wastes
would be required. Second, leak
detection and repair programs would be
required for certain valves, pumps,
compressors, pressure relief devices,
and closed-vent systems. If wastes that
exhibit the TC also have concentrations
of organic constituents exceeding the
regulatory threshold, they will be -
subject to this first phase of regulation
for air emissions.
/. Relationship to Other Regulatory
Authorities
1. Comprehensive Environmental
Response, Compensation, and Liability
Act(CERCLA)
Although promulgated in fulfillment of
a RCRA mandate, today's rule may
affect, to varying degrees, remediations
performed under CERCLA authority.
Such effects or interactions, when they
arise, will be associated with section
121fd) of CERCLA, which requires
CERCLA remedial actions to comply
with all applicable or relevant arid
appropriate requirements (ARARs) of
other federal and state laws, including
RCRA.
Several commenters questioned the
applicability of the TC to CERCLA sites
and argued that the TC would constrain
the discretion of Remedial Project
Managers and On-Scene Coordinators.
However, CERCLA section 121(d) is
clear that CERCLA remediations must
comply with Federal and State ARARs.
Accordingly, RCRA regulations,
including today's TC, are incorporated
into the CERCLA decision-making and
remediation process to augment controls
already in place under the CERCLA
program.
In addition, a few commenters argaed
that as a result of today's rule, a greater
number of hazardous waste
determinations would be made during
CERCLA remediations. Consequently,
"thousands of additional Superfund
sites" would be created, attributable in
large part, one commenter notes, to
petroleum and petrochemical waste that
will exceed TC levels. The Agency
disagrees with the commenters. While it
is clear that CERCLA remediations must
comply with Federal and State ARARs,
the TC is not used by CERCLA to
determine whether or not to undertake a
clean-up action. Rather, the TC will
apply to decisions concerning the
management of solid wastes (e.g., soil
and debris) generated during cleanup •
activities.
2. Clean Water Act
a. Conflict with NPDES Effluent.
Guidelines and Pretreatment Standards,
Many commenters argued that the
regulatory levels in the proposed TC.' •
conflict with NPDES effluent guidelines
and pretreatment standards under the
Clean Water Act (CWA). Several
commenters stated that in many cases,
the proposed TC regulatory levels are
lower than the concentrations allowed
in wastewaters directly discharged to
surface waters in compliance with
NPDES effluent guidelines. Commenters
also stated that many wastewaters that
are indirectly discharged to publicly
owned treatment works in compliance
with pretreatment standards will exhibit
theTC.
Most of the commenters argued that it
would be difficult to justify labeling a
wastewater as "hazardous" under
RCRA, but."safe" under the CWA. One
commenter claimed that differential
treatment of identical wastewaters is
particularly difficult to justify because.
leaks from on-site wastewater
management operations normally
migrate to the same boclies of water that
receive NPDES-permitted discharges. ,
EPA acknowledges the possibility that
some wastewaters that meet NPDES
effluent guidelines or pretreatment
standards raay exhibit the TC. However,
because the statutory bases for setting
regulatory levels ars different under the
CWA and RCRA, the treatment
standards and effluent limitations
established under the CWA are not
inconsistent with the TC rule. The CWA
requires EPA to set effluent limitations
to control discharges of toxic pollutants
"* * * which shall require application
of the best available technologj'
economically achievable * * *" and to
set more stringent effluent limitations
where necessary to meet applicable
water quality standards (see CWA
section 301(b)): RCRA, however,
mandates that EPA identify wastes
which may be a threat to human health
or the environment. The criteria for the
identification and listing of hazardous
waste requires EPA to take into account
"* * * toxicity, persistence, and •
degradability in nature, potential for
accumulation in tissue, and other related
factors such as flammability,
corrosiveness, and other hazardous-
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11838 Federal Register / Vol. 55, No. 61 / Thursday, March 29, 1990 / .Ruies and_
characteristics" (see RCRA section
3001(a)). These criteria are different
from those used under the CWA.
Accordingly, the two statutgry
programs have different goals. EPA
believes that the TC regulatory levels
represent concentrations above which a
wastewater poses a potential hazard to
human health and the environment, if
mismanaged, even if it has been treated
to some degree. Therefore, owners, and
operators of wastewater treatment
facilities that treat wastewaters
exhibiting the TC will be required to
comply with all applicable regulations
under RCRA and the CWA.
b'. Permit Requirements for
Wastewater Treatment Facilities. Many
commenters stated that under the
proposed TC, many wastewater
treatment facilities will become
hazardous waste treatment facilities
subject to full RCRA permitting
requirements. These commenters were
concerned that the costs to industry of
preparing permit applications and
complying with RCRA regulations for
hazardous waste treatment facilities
will be prohibitive. Some commenters
argued that EPA has insufficient
resources to process permit applications
from all of the wastewater treatment
facilities that will require permits.
Although owners and operators of
some wastewater treatment facilities
that use newly-regulated surface
impoundments could be subject to
RCRA permitting requirements, EPA
believes that the actual number of
facilities requiring permits will not be
large. The Regulatory Impact Analysis
for this rule indicates that other options
available to wastewater treatment
facilities treating Wastewaters
exhibiting the TC are likely to be more
cost-effective than obtaining an RCRA
permit [see section VI. 8 for a more
detailed discussion}. In particular, an
alternative that the Agency expects may
be attractive to many owners and
operators is the replacement of surface
impoundments with tanks. Retrofitting
existing surface impoundments to meet
RCRA requirements for hazardous
waste management facilities will often
be more expensive than building tanks
that are subject to CWA requirements in
lieu of RCRA permitting requirements.
("Wastewater treatment units" are
exempt from the hazardous waste
management standards under 40 CFR
254.1(g)(6) and 265.1(c)(10). Similarly,
"totally enclosed treatment facilities"
are exempt under 40 CFR 264.1(g)(5) and
205.1(c)[9).) Thus, there are.options
available to owners/operators for whom
RCRA standards may be too costiy.
There may be some wastewater
treatment facilities that opt to continue
using surface impoundments to manage
wastewaters exhibiting the TC, and
these facilities will enter.the RCRA
permitting system. However, the Agency
does not believe that there will be such
a large number of facilities that it will
overwhelm the. Agency's permitting
capabilities.
c. Sludges from Publicly Owned
Treatment Works (POTW). The
preamble to the June 13,1986 proposed
rule requested comments on the
regulation of sewage sludge under
RCRA and under the CWA. The
preamble stated that EPA was
considering an exemption from RCRA
regulation for sludges from publicly
owned treatment works (POTW sludges)
upon the promulgation of sewage sludge
management standards pursuant to
section 405(d) of the CWA.
A number of commenters, including
many municipalities, responded to this
request for comments. Although a few
commenters opposed an exemption from
RCRA for POTW sludges, the
commenting municipalities supported an
exemption from RCRA. These
municipalities stated that sewage sludge
management regulations, in addition to
pretreatment standards, are sufficient to
protect human health and the
environment without additional
regulation under RCRA. Commenters
stated that regulating POTW sludge
under RCRA will place a significant
economic burden on municipalities and
will cause municipalities and EPA to
face duplicative administrative costs
and regulatory confusion.
EPA does not agree with commenters
that regulation of POTW sludge under
RCRA will place a significant economic
burden on municipalities or increase the
burden of implementation. EPA's office
of Water tested 18 POTW sludge
samples using the TCLP; none of the
samples tested exhibited the TC at the
proposed regulatory levels (Ref. 18).
Because the final TC regulatory levels
are higher, than the proposed regulatory
levels, the Agency believes that few, if
any, POTW sludges will exhibit the TC.
Thus, most POTW sludges will not be
classified as hazardous waste under
RCRA.
Although EPA does not believe it is
necessary to exempt POTW sludges
from RCRA at this, time, the Agency may
reconsider this decision after the
sewage sludge management regulations
are promulgated. In the unlikely event
that a particular POTW sludge does
exhibit the TC, the municipality may use
the pretreatment program under the
CWA to eliminate the indirect
discharges of the pollutants that are
causing the sludge to exhibit the TC.
3. Safe Drinking Water Act
Several commenters noted that the
proposed regulatory level for chloroform
is lower than the primary drinking water
standard for trihalomethanes (a class of
organic chemicals that includes
chloroform) established under the Safe
Drinking Water Act (SOWA). Most of
these commentersi consequently
declared that the regulatory level had
been set too'low, and they argued that it
would be unreasonable to regulate
ordinary drinking water as a hazardous
waste, Some commenters asserted that
an industrial facility taking water from a
public water supplier (a facility
supplying drinking water in compliance
with the SDWA roles) could find that its
noncontact cooling water becomes a
hazardous waste after it is passed
through the plant and is disposed.
In today's'final ,rule',' the regulatory
level for chloroform has been raised
from that proposed in the June 13,1986,
notice of proposed rulemaking. The
change is because of two modifications
to the data originally used to set the
regulatory level; first, the chronic
toxicity reference level for chloroform is
roughly 12 times Higher than when
originally proposed (see 53 FR18024)
and, second, due to the changes in the
model, the DAF is about 7 times higher
than the one originally proposed. .
Together, these two changes result in a
regulatory level that is higher than both
the original regulatory level and the
SDWA standard for trihalomethanes.
Non-contact cooling water or other
wastewaters derived from public water
supplies complying with the SDWA thus
should not exhibit the TC for chloroform
unless these wastewaters are
contaminated by other sources.
4. Federal Insecticide, Fungicide, and
Rodenticide Act (FIFRA)
a. Pesticide Wastes. The Federal
Insecticide, Fungicide, and Rodenticide
Act (FIFRA) authorizes EPA regulation
of pesticide sale, distribution, use, and
disposal. Since RCRA regulations cover
solid wastes which include pesticide
product wastes, 1:hese wastes may be
regulated under both FIFRA and RCRA.
Until recently, pesticide disposal
under FIFRA was primarily controlled
by mandating that product labeling
include instructions for the proper
disposal of the pesticide and its
container. Recent amendments to
FIFRA, effective October 25,1988,
authorize the Administrator to impose
additional requirements relating to
storage, transportation, and disposal of
certain pesticides. For example, EPA
under FIFRA may issue requirements
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Federal Register / Vol. 55. No. 61 / Thursday, March 29, 1990 / Rules and Regulations 11839
and procedures for the storage,
transportation, and disposal of
suspended or cancelled pesticides and
of rinsates or containers associated with
the pesticides. Also, EPA may require
that applicants for registration of a
pesticide submi^information regarding
methods for safe storage and disposal of
the pesticide, and that applicants for
registration provide evidence of
sufficient financial resources to provide
for disposal in the event of suspension
or cancellation.
A number of pesticide-related wastes
are listed as hazardous under 40 CFR
part 261. The listings include four
groups: The first, at § 261.31, includes
certain discarded unused pesticide
formulations containing tri-, tetra-, and
pentachlorophenols (F027) or certain
compounds derived from the
chlorophenols; these are listed as acute
hazardous waste. This listing includes
approximately 20 phenoxy pesticides
and their salts and esters. Today's rule
will add the constituent 2,4,6-
trichlorophenol, which is used as an
active ingredient in pesticide products,
to the TC list. Because products
containing this constituent are
separately listed under .F027, the
promulgation of specific toxicity limits
will not affect their regulation under
RCRA (i-e., they will continue to be
regulated as acute hazardous wastes at
all concentrations, both above and
below the TC level).
The second group, at § 262.32, consists
of "K" wastes from the production of
specific pesticides, such as wastewater
treatment sludges from the production of
the pesticide chlordane (K032); these are
listed as toxic wastes. Again, however,
because these wastes are listed, they
will not be affected by the regulatory
levels of the TC, but will continue to be
subject to regulation regardless of
concentration levels.
The third grouping, at § 261.33 (e) and
(f), consists of "P" and "U" wastes.
Section 261.33 lists certain commercial
chemical products as hazardous when
discarded or intended for discard.
Approximately SO pesticide active
ingredients are listed as acute
hazardous wastes under § 261.33(e),
while 83 pesticide active ingredients are
listed under § 261.33ff} as toxic
hazardous wastes. Pesticide products
containing these chemicals as sole
active ingredients or the pure or
technical grade of'these chemicals are
regulated under both RCRA and. FffRA
when they become wastes. Generally.
products-containing these ingredients as
one of multiple active ingredients are
not regulated (at this, time) as hazardous
wastes under subtitle C of RCRA unless
they meet one of the characteristics;
their disposal is still subject to any
applicable FIFRA and RCRA subtitle D
requirements. For the majority of the 133
listed pesticides, today's rule will not
change their status under RCRA; waste
pesticides that are either pure,'technical
grade, or sole active ingredient products
will continue to be subject to regulation
as hazardous at all concentrations under
RCRA subtitle C. Wastes from multiple
active ingredient products that do not
exhibit a characteristic will still be
regulated under any applicable FIFRA
and RCRA subtitle D requirements.
Six pesticide wastes that are currently
regulated on a concentration basis.
under the existing EPTC at § 261.24,
form the fourth group. These six
pesticides (endrin, lindane,
methoxychlor, toxaphene, 2,4-D, and
silvex) will be retained in the new rule
with their current concentration limits,.
which are based on a DAF of 100. The
significant difference between the
listings and the TC is that, while
multiple active ingredient products are
hot covered by the listings, they are
covered under the characteristic. Thus,
increasing the number of pesticida!
constituents encompassed by the TC
(whether or not they are also listed J,
brings more multiple active ingredient
formulations into the subtitle C system.
Consequently, today's rule is expanding
regulation of pesticide wastes under
RCRA."
Although EPA is adding pesticides to
the TC list of constituents, today's rule
will not have a significant effect on
many pesticide users who generate
wastes. RCRA regulations contain
special requirements that affect the
extent to which pesticide users will
become subject to additional RCRA
regulation;
• Household pesticide wastes are,
like other household wastes, exempt
from RCRA.
• Farmers who triple rinse their
containers and dispose of the rinsate on
their own farm in a manner consistent
with 40 CFR 262.51 and label
instructions are exempt from RCRA
requirements.
• Other small quantity generators
under § 261.5 need comply only with
reduced requirements. Many pesticide
users are small quantity generators.
• Under f 261.7, properly emptied
containers may be exempted from
further RCRA requirements. Thus, many
pesticide containers may not be subject
to regulation as hazardous wastes.
As a result, the principal effects of
today's final rale will be felt by
commercial applicators, such as aerial
applicators and pest control operators.
who are not eligible for the special
requirements applicable to fanners and
who may* use sufficiently large volumes
of pesticides that they exceed the small
quantity generator limitations. If they
use large quantities of multiple active
ingredient pesticide products that have
not previously been regulated, such
commercial applicators may be newly
subject to the RCRA hazardous waste
management requirements.
b. Treated Wood Wastes, the Agency
is promulgating TC regulatory levels for
certain chemicals—for example; cresols
and pentachlorophenol—that are
commonly used as wood preservatives.
In its review of wood preservative
chemicals under FfFRA, EPA concluded
that these wood'preservafives may
continue to be used under certain
circumstances, and the Agency decided
to allow disposal of treated wood by
means of ordinary trash collection,
burial, or incineration (49 FR 28666, July
13,1984, and 51 FR 1334, January 10,
1986). However, the mandates of FIFRA
and RCRA are different. EPA has
previously stated that even if it were
determined that certain ground uses of
treated wood did not pose unreasonable
risks,, wood wastes might still be
regulated under RCRA subtitle C (45 FR
78531, November 25,1980). Under
FIFRA, the Agency may determine that
the economic benefits of continued use
of a pesticide outweigh any potential
risks posed by the pesticide. This does
not mean, however, that materials
treated with pesticides should not be
managed in a controlled manner under
RCRA at the end of their useful lives, to
.ensure that long-term risks are
minimized.
Some treated wood that is hazardous
solely because it fails the EP toxicity
test for arsenic which is not a hazardous
waste for any other reason or reasons is
exempt from regulation as hazardous (40
CFR 261.4(b)(9)}. The exemption is
limited, to wood wastes generated by
persons who use wood products for their
intended end use. Several commenters
claimed that large quantities of treated
wood wastes will be newly regulated as
hazardous ander the TCv and they
argued that this result is inconsistent
with other,EPA policies and regulations.
Most of these commenters
recommended that EPA expand the
existing exemption for arsenic-treated
wood waste to encompass all treated
wood that exhibits the TC.
EPA has decided not to expand the
existing exemption for arsenic-treated
wood; If a wood waste does exhibit the
TG.for a constituent other than arsenic,
or if the waste is hazardous waste for
any other reasons or reasons, the
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Federal Register / Vol. 55. No. 61 / Thursday, March 29. 1990 / Rules and Regulation^
Agency believes that the waste should
be regulated as hazardous, in order to
protect human health and the
environment. The arsenic-treated wood
exemption is not being revoked at this
time, but it may be reevaluated in the
future.
5. Food. Drug, and Cosmetic Act (FDCA)
a. Food Wastes. Several commenters
noted that allowable levels set by the
Food and Drug Administration (FDA)
under the Food, Drug, and Cosmetics
Act (FDCA) are, in some cases, higher
than the proposed TC regulatory levels
for the same chemicals. Most of these
commenters then asserted that if it is
safe to consume substances containing
pesticides or additives, it must also be
safe to place such substances in
municipal landfills. Some commenters
expressed concern that food wastes that
comply with FDCA pesticide tolerance
or action levels may nevertheless have
to be handled as hazardous wastes as a
result of the TC. One food processing
Industry trade association requested
that the final TC rule state that any
waste from food already in compliance
with a tolerance or action level set by
EPA or FDA is nonhazardous.
The Agency acknowledges that for
certain chemicals in waste, it proposed
TC regulatory levels lower than FDCA
tolerances or action levels in food.
However, it is inappropriate to make a
direct comparison of these two sets of
levels. FDCA levels are set for
concentrations in food products, while
TC levels apply to concentrations in the
leachate from waste materials. Because
not all toxic constituents leach from the
waste, levels in the leachate are lower
than jn the waste material itself.
Accordingly, for a food waste to be
hazardous, the Waste would have to
have constituent concentrations higher
than the TC levels. The Agency is
unaware of any food-related wastes that
will be regulated as hazardous under the
TC rule. (In addition, unlike the FDCA,
RCRA does not allow consideration of
economic factors in establishing
regulatory levels of concern.)
If any food waste does exhibit the TC,
it may be subject to lesser requirements
as household waste (40 CFR 261.4(b)(l))
or under the small quantity generator
provisions (40 CFR 261.5). For non-
household food wastes that fail the TC
(i.e., leachate from the waste contains
contaminants in levels equal to or above
the regulatory levels promulgated in
today's rule) and that are generated in
large quantities, it is appropriate that
they be managed in a.controlled manner
to protect human health and the
environment. Because EPA sees no
conflict between the TC rule and
tolerance or action levels under FDCA,
this rule contains no exemption for
wastes that meet the FDCA standards.
b. Pharmaceutical and Cosmetic
Wastes. Several commenters, arguing
that the proposed TC levels were tod
low, pointed out that the proposed
regulatory levels are lower than FDCA-
allowed levels for the same chemicals in
drugs or cosmetics.
Although the proposed TC regulatory
levels for certain chemicals were lower
than the FDCA levels for the same
chemicals in drug and cosmetic
products, the levels are higher in the
final rule. Moreover, it is clear that
different factors must be taken into
account when regulating these
constituents hi drugs and cosmetics
rather than in solid wastes, as confirmed
by different statutory mandates. The
constituents hi drugs and cosmetics
products, often used in very small
quantities, serve a useful function and
may be therapeutic in certain quantities
and under proper circumstances.
However, this does not mean that these
same constituents should not be
controlled where found at TC levels in
waste materials.
Of cours6, drug and cosmetic wastes
generated in households are not subject
to subtitle C regulation (40 CFR
261.4(b)(l)) nor are wastes generated by
small quantity generators (less than 100
kg/mo of non-acute hazardous waste-
see 40 CFR 261.5). However, drug and
cosmetic products when discarded may
present risks to human health and the
environment if disposed in,large
volumes. Thus, EPA maintains that
regulation of large quantities of drug or
cosmetic wastes exhibiting the TC is
appropriate and not in conflict with the
existing FDCA program.
6. Used Oil Recycling Act ,
The Used Oil Recycling Act of 1980
(UORA), which amended RCRA, was
intended to increase safe recycling and
reuse of used oil. It established that it is
hi the national interest to recycle used
oil in a manner that both protects public
health and the environment and
conserves energy and materials. The
UORA has been incorporated in section
3014 of RCRA, '
Section 3014 of RCRA, as amended by
HSWA, requires EPA to make a
determiriation of whether to list or
identify used oil as'a hazardous waste
(see RCRA section 3.014(B)). In response
to this statutory directive, EPA proposed
to list most types of used oil, including
recycled used oil, as a hazardous waste
on November 29.1985'(see 50 FR. 49258).
EPA subsequently decided in November;
1986 not to list used oil because the
Agency believed that the listing would
discourage recycling of used oil and
could result in an increase in the amount
of used oil that is disposed of or illegally
dumped. The Agency decided to .
continue to study whether used oil that
is disposed should be listed as a
hazardous waste under BCRA or
regulated under different statutes (see 51
FR 41900 (November 19,1986)). EPA's
decision to withdraw the proposed
listing of used oils was invalidated by
the D.C. Circuit Court of Appeals in
1988. The Agency was directed by the
Court to reconsider the listing of used oil
as a hazardous waste based on the
technical criteria contained in RCRA
section 3001.
Some commenters claimed that used
oil would be brought into the subtitle C
system under the TC proposal. They
stated that used ciil is likely to fail the
TC test for both aromatic hydrocarbons
(e.g., benzene) and chlorinated solvents
(e.g., trichloroethylene and
tetrachloroethylene). The commenters
argued that regulating used oil as a
hazardous waste would be inconsistent
with the intent of the UOR^, as well as
with current Agency policies regarding
used oil.
Under today's rale, used oil will be
regulated as a hazardous waste only: (1)
If it exhibits one or more of the
hazardous waste characteristics defined
in subpart C of 40 CFR part 261
(including the TC as finalized today)
and (2) if it is disposed of (rather that
recycled). On the other hand, used oil
that exhibits one or more of the
hazardous waste characteristics and is
recycled is exempt from regulation (see
40 CFR 261.6(a)(3)(iii)) except as
provided in subpart E of 40 CFR part
266. In addition, RCRA prohibits the use
of used oil as a dust suppressant or for
road treatment ii: it is contaminated with
dioxin or mixed with a hazardous
waste. Thus, used oil that exhibits one
or more of the characteristics (except for
ignitability) cannot be used as a dust
suppressant, hi particular, the
regulations have the following effect:
• Solid waste that is hazardous waste
because it fails a characteristic and that
is recycled (except by burning or use as
a dust suppressant) is exempt from
regulation.
• Characteristically hazardous used
oil that is disposed of (or incinerated
without recovery of energy value) is
subject to full RCRA subtitle C
regulation.
• Characteristically hazardous used
oil that is being burned for energy
recovery is subject to subpart E of part
266—i.e., off-specification used oil is
subject to certain administrative
requirements, while specification used
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Federal Register / Vol. 55. No. 61 / Thursday, March 29, 1990 / Rules and Regulations 11841
oil is subject only to the analysis and
recordkeeping requirements of 40 CFR
266.43(b) (1) and (6).
• Characteristically hazardous used
oil is prohibited from being used as a
dust suppressant, unless it is hazardous
solely for exhibiting the ignitability
characteristic'(see 40 CFR 266.23(b}).
• Characteristically hazardous used
oil that is recycled in any manner other
than being burned for energy recovery
(e.g., by being rerefined) is exempt from
subtitle C regulation.
Therefore, today's rule will not affect
the regulatory status of most recycled
used oil. In fact, today's rule should
encourage the recycling of used oil, and
not discourage its recycling as suggested.
by some commenters. It should also be
noted that some percentage of used oil
already is defined as hazardous (i.e.,
exhibits One or more of the hazardous
waste characteristics and is disposed).
Consequently, the amount of used oil
that is affected by this rule and is either
disposed of or recycled by being burned
for energy recovery or used as a dust
suppressant will be even less.
The Agency is currently determining
how best to deal with used oil listing
and management issues. Section 3014 of
RCRA also requires JEPA to promulgate
management standards for used oil that
is recycled. Standards for controlling
.used oil which is recycled were
proposed on November 29,1985 (50 FR
49212), but have not been finalized. The
Agency will be addressing these issues
as well as addressing the listing
determination in the near future.
7. Toxic Substances Control Act (TSCA)
EPA has decided to exempt from the
application of this rule certain
polychlorinated biphenyl (PCB) wastes
that are regulated under the Toxic
Substances Control Act (TSCA) and
would be identified as hazardous
because of today's rule. Specifically,
PCB-containing dielectric fluids
removed from electrical transformers,.
capacitors, and associated PCB-
contaminated electrical equipment may
exhibit the TC, and thus become
hazardous wastes when disposed, not
because .they contain PCBs (which are
not among the constituents regulated
under the TC) but because they may
contain other TC constituents, such as
chlorinated benzenes. The Agency has
decided to exempt such wastes from the
subtitle C management standards
because new regulation of these wastes
under RCRA may be disruptive to the
mandatory phaseout of PCBs in certain
electrical transformers and capacitors.
In addition, the Agency believes that the
regulation of these wastes under TSCA
is adequate to protect human health and
the environment. However, the
exemption applies only to those
dielectric fluids, (as described above)
that are fully regulated under TSCA.
Other PCB-containing wastes that are
hazardous (i.e., listed or exhibit a
hazardous waste characteristic
including the existing EPTC wastes—
waste codes D004 through D017) are
subject to all applicable subtitle C
standards. Furthermore, these non-TC
hazardous wastes that are (1) liquids
containing PCBs at concentration
greater than 50 ppm, or (2) solids
containing PCBs listed in Appendix III of
part 268 at concentrations greater than
1000 mg/Kg, are prohibited from land
disposal under 40 CFR part 268.
The disposal and storage of PCB
wastes is regulated under TSCA section
6(e)(l) authority rather than under
subtitle C of RCRA. Since the enactment
of TSCA, the manufacture, processing,
and distribution in commerce of PCBs
(without an exemption) has been
banned and the use of PCB without
authorization has been banned. In
addition, EPA has developed •
comprehensive PCB disposal regulations
under TSCA. This regulatory framework
.includes specific disposal requirements
for defined classes of PCB wastes,
specific marking requirements for PCB
items, facility recordkeeping
requirements, approval requirements for
disposers, and a proposed notification
a.nd manifesting system modeled on the
subtitle C "cradle to grave" tracking
system.
One commenter stated that utility
transformer dielectric fluids are likely to
exhibit the revised TC and urged the
Agency to exempt PCB-containing utility
transformer dielectric fluids from the
rule. The commenter noted that the
regulation of PCBs is unique because the
manufacture of PCBs (without an
exemption) has been banned^ Thus, the
critical regulatory concern with respect
to these PCB wastes is the need to
expedite safe disposal of'the chemical.
The commenter stressed that if PCB
wastes were to be regulated now under
RCRA as well as under TSCA, serious
legal, practical and.administrative
complications could result.
The Agency agrees with the
commenter. The most significant
potential negative impact of dual
regulation of these wastes under both
RCRA subtitle C and TSCA results from
the unique scope and timing of PCB
disposal. The Agency estimates that
approximately 312 million pounds of
PCBs are dispersed among nearly 30
million discrete units of electrical
equipment. The TSCA regulations
require the phaseout of certain PCB-
containing electrical transformers, and
EPA expects that the TSCA mandatory
phaseout requirements and restrictions
will render the next three years a peak
period for PCB disposal. Under the
authority of the TSCA mandatory
phaseout, by October 1,1990, owners of-
secondary network higher voltage
transformers located in or near
commercial buildings are required to
either remove or reclassify these
transformers. (Reclassification
necessitates draining of all PCB fluids
from the unit, and replacing them with
non-PCB fluids or low concentration
PCB fluids, and keeping the transformer
in full service, under loaded conditions,
for a minimum of three months.) In
addition, the phaseout restrictions affect
lower secondary voltage network units
of PCB-containing electrical
transformers located in or near
commercial buildings; by October 1,
1993, such transformers must either be
• removed or be reclassified, or an
alternative option for lower voltage
units allows for providing enhanced
electrical protection on such units by
October 1,1990. Radial PCB-containing
electrical transformers must either have
enhanced electrical protection or be
removed.
The TSCA program, with which the
regulated community is familiar, is
specifically tailored to deal with the
problem of widely dispersed waste
generation and the timely disposal of a
chemical that is no longer commercially
produced. The confusion that could
result from the addition of requirements
under a separate regulatory disposal
system, and the RCRA disincentives to
waste production, would cause
significant disruption to the expeditious
disposal of large quantities of these PCB
wastes if these wastes were to become
subject to the RCRA hazardous waste
regulations.
In addition, the Agency believes that
the existing system for PCB disposal,
including the existing TSCA disposal
regulations and recent additions to the
program (e.g., the proposed notification
and manifesting rule, published at 53 FR
37436), are adequate to protect human
health and the environment with respect
to the disposal of these wastes. Thus,
further regulation under RCRA for PCB-
containing dielectric fluids and
associated PCB-contaminated electrical
equipment does not appear-to be
necessary at this time. The Agency will
also evaluate the integration of the.
TSCA PCB regulations with the RCRA
hazardous waste regulations for other
PCB-containing wastes which are
identified or listed as hazardous.
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£42 Federal Register / Vol. 55, No. 61 /Thursday, March 29, 1990 / Rules and Regulations
K ji
EPA received many comments
concerning implementation of the TC
rule. The comments addressed issues
including the schedule for companies
and municipalities to come into
compliance with subtitle C
requirements, exemptions and
applicability, implications for permit
modifications, and administrative
requirements. Major comments.on
implementation are summarized and
addressed below; Section V of this
preamble further discusses how the
Agency will implement today's rule.
1. Notification
In the June 13, 1986 Federal Register
notlce,EPA proposed to waive the
RCRA section 3010 notification
requirement for persons who manage TC
wastes and have already: (1) Notified
the Agency that they manage other
hazardous wastes and (2) received an
EPA identification number. Virtually all
commentcrs who addressed the
notification requirement supported
EPA's proposal. However, one state
agency opposed the proposal, on the
grounds that a waiver would hinder >
efforts to develop a more accurate and
complete understanding of hazardous
waste management practices within the
United States.
EPA has decided, as proposed, to
waive the notification requirement for
TC waste handlers that have already
notified the Agency that they manage
hazardous wastes and have received an
EPA identification number. The Agency
believes that, given the vast scope of the
TC rule, a notification requirement for
persons already identified within the
hazardous waste management universe
would present an administrative burden
without providing any significant
benefits to human health and the
environment.
2. Effective Date
Several commenters claimed that the
6-month effective date of the TC rule
would not provide them with sufficient
time to come into compliance with the
full array of hazardous waste
regulations. Some commenters argued
that it would be impossible for
generators of TC wastes to test theii
wastes, obtain EPA identification
numbers, arrange for transport and off-
site management of their wastes, modify
their short-term storage (La,
accumulation) practices, and institute
the necessary recordkeeping and
reporting procedures within a 6-month
timo frame. The commenters stated that
the time constraints are especially
unreasonable in light of the shortages of
laboratory and TSDF capacity that can
be expected to result from the TC
revisions. Other commenters claimed
that TSDFs will require more than 8
months to come into compliance with
the interim status standards of 40 CFR
part 265 (e.g., personnel training,
contingency planning, and .financial
responsibility).
EPA appreciates the concerns of the
commenters, and the Agency is aware
that all of the commenters addressing
the effective date for the TC rule
encouraged EPA to adopt a delayed
effective date for most, if not all,
requirements. However, RCRA section
3010(b) requires that hazardous waste
regulations become effective 6 months
after the date of promulgation unless
EPA has good cause to establish an
earlier effective date. Thus, the effective
date for the final TC rule will be 6
months from the date of promulgation.
However, EPA is promulgating
different compliance dates for two
different categories of waste generators:
'(1) All generators of more than 100 and
less than 1,000 kg/month of hazardous
waste (small-quantity generators) must
come into compliance with subtitle C
requirements for management of their
TC waste within one year of today; and
<2) all generators of 1,000 kg/month or
more of hazardous waste are required to
comply with all subtitle C requirements
for TC wastes within six months of
today, on the effective date of the rule.
All generators of over 1,000 kg/month
of hazardous waste are required to
comply with all applicable RCRA
regulations for their TC wastes on the
effective date of this rule. (The generator
quantity refers to all of a generator's
hazardous waste, not just newly
hazardous TC waste.) The Agency
recognizes that this compliance category
will include two groups of generators:
current hazardous waste generators,
including small quantity hazardous
waste generators who will be generating
additional hazardous wastes and
generators of large quantities of solid
wastes who will be regulated as
hazardous waste generators for the first
time. EPA believes that both of these
'groups of generators should
predominantly be large businesses, and
either be familiar with the waste
management regulations or toe in a
position to come .into compliance with
'the requirements within'the six month
period:. These persons .should have been
aware of the Agency's statutory
commitment and have had ample notice
of the impending TC rule through fee
proposed rule and supplemental notices.
. On the-other hand, the Agency IS
allowing an additional six months from
the effective date (i.e., one year from
today) for generators .of greater than .100
but less than 1,000 kg/month of
hazardous waste (small'quantity
.generators) to comply with all
applicable subtitle C regulations. (As
withlhe over 1,000 kg/month category,
this quantity refeirs to the total quantity
of a generator's hazardous waste, not
justnewly hazardous TC waste.) The
TChas the potential to affect an
extremely large number of handlers that
.never before have been subject to the
hazardous waste regulations; many of
these firms are small businesses.
Handlers that will assume small '
quantity generator statuses a result of
the TC rule are most likely not regulated
under'subtitle C at the present time.
Thus, these handlers are less likely to be
familiar with the waste .management
regulations, or because of their small
business..status, will need more than sir
months to come into compliance with
the regulations.
As already indicated, these handlers
are likely to be small entities and may
be unaware that their practices, which
were not regulated in the past, will now
be regulated as a result of today's rule.
The Agency recognizes that these new
handlers of small! quantities of TC
wastes (over 100 but less than 1,000 kg/
month) may have to test their wastes,
obtain EPA identification numbers,
arrange for transport and off-site
management of their wastes, modify
their short-term sitorage (i.e.,
accumulation) practices, and institute
the necessary recordkeeping and
reporting procedures. As recognized by
the Agency in establishing special
requirements for small quantity
generators, the burden of initial
compliance may fall relatively harder on
these generators (see 51FR10146,
March 24,1986). Thus, to lessen the
burden on the handlers of small
quantities of TC wastes, the Agency has
developed an outreach program targeted
for the small quantity generators which
will urforrn new jjenerators of the
required steps necessary to enter the
hazardous waste management syslem,
Effective program outreach, however,
will take more than 6 months.
In amending RGRA in 1984, Congress,
in requiring EPA to promulgate
regulations for small quantity
generators, indicated that the Agency
should consider the impacts on small
businesses, while still providing
protection to human health and the
environment. While_ this rule is riot
promulgated pursuant to this provision,
we believe the intent of Congress is for
the Agency (in promulgating any rule
substantially affecting small quantity
-------
Federal Register / Vol. 55. No. 61 / Thursday. March 29. 1990 /Rules and Regulations
11843
generators) to consider such impacts
and to provide procedural adjustments
where appropriate. EPA believes that
extending the compliance date for this
group of generators will allow the
Agency time to provide necessary
assistance and outreach to these
generators arid will allow sufficient time
for small quantity generators to comply
with the full range of applicable subtitle
Crequirements. Finally, by delaying the
effective date of the TC for small
quantity generators, the Agency will be
able to concentrate its initial
implementation efforts on large quantity
generators, who will generate the vast
majority of waste brought into the
RCRA subtitle C system under this rule.
Thus, because the delayed compliance
date for small quantity generators
enables the Agency to focus its attention
on the waste generators expected to
produce the largest volumes of waste, it
maximizes protection of human health
and the environment.
In summary, the Agency believes that
allowing an additional six months for
small quantity generators to come into
full compliance with the TC will serve
two purposes. First, it will allow the
Agency time to educate small quantity
generators on the RCRA rules, while at
the same time, allowing the Agency to
focus immediate implementation efforts
on large generators of hazardous waste.
Second,.it will provide the necessary
time for small quantity generators to
comply with subtitle ^requirements as
a result of the TC.
3. Permitting
Several commenters expressed
concern that they would not be able to
submit required permit modifications
before the effective date of the rule.
Some commenters also expressed
concern that the TC revisions could
place a significant burden on the system
for permitting hazardous waste
treatment, storage, and disposal
facilities.
The commenters recommended a
number of different mechanisms for
reducing the prospective burdens on the
permitting system, such as (1) Allowing
permitted facilities to operate under
interim status with respect to newly
regulated wastes; (2) handling requests
from permitted facilities to manage TC
wastes as minor permit modifications,
rather than as major permit
modifications (especially in the case of
facilities that are already permitted to
manage listed wastes containing TC
constituents); (3) requiring permitted
facilities to apply for major permit
modifications by the effective date of
the TC rule, but not requiring them to
actually obtain the modification until a
later date; or (4) delaying the effective
date of the final rule.
EPA has promulgated amendments to
the procedures for permit modifications
for treatment, storage, and disposal
facilities on September 28,1988 (53 FR
37934). These changes to the regulations
should generally allay the concerns
expressed by the commenters. Although
the new permit modifications rule will
riot automatically be effective in
authorized states, EPA expects that
many authorized states will adopt the
provisions and EPA plans to use the
new permit modification procedures to
implement the TC. The new permit
modification procedures are further
explained in section V.
IV. Regulatory Levels
The regulatory levels established in
today's rule are based on two
elements—the toxicity of each
constituent and the expected fate of the
constituent when released into the
environment. The latter element is
expressed as a dilution/attenuation
factor (DAF), which, when multiplied by
the toxicity value, results in the
regulatory level. It is this level that,
when compared to the results of the
TCLP, defines a waste as hazardous. If
the waste leachate generated through
the TCLP contains constituents equal to
or above the regulatory levels in today's
rule, the waste is a hazardous waste.
This section summarizes the Agency's
basis for selecting the final list of
constituents and the regulatory levels
that are being promulgated in today's
rule.
A. List of Constituents
1. Proposed List
The Agency initially proposed
regulatory levels for 38 new organic
constituents, proposed to modify the
regulatory levels for the six organic
constituents that are regulated under the
existing EPTC, and proposed to retain
the existing levels for the eight inorganic
constituents regulated in the existing
EPTC (see Table IV-1).
2. Constituents for Which Final
Regulatory Levels Are Not Now Being
Promulgated
The model used to predict DAFs for
today's rule accounts for hydrolysis,
which may occur during the transport of
a constituent through the environment. If
a constituent hydrolyzes during
transport, its concentration will
decrease more rapidly than it would if it
were influenced by dispersion alone.
Therefore, the DAF for a constituent that
hydrolyzes during transport will be
higher than that for a constituent that
does not hydrolyze. However, the
products that are formed because of
hydrolysis of the constituent also-may
be toxic.
TABLE IV-1.—TC CONSTITUENTS AND REGULATORY LEVELS PROPOSED JUNE 13,1986
HWNO '
D016
D004
D005
D019
D020 ,
D006 .
D021
D022
D023....
D024
D025
D007 ,. '
D026..
D027....1 ;
D028.. ;.
D029 ' ' r
DJ030.........
D031
Constituents
•
Arsenic
Barium
Benzene
Bis(2-ch!oroethyl) ether.....
Carbon disulfide
Carbon tetrachloride
Chlordane
Chlorobenzene
Chloroform .-.
Chromium
o-Cresol
m-Cresol —
p-Cresol
2,4-D
1 ,2-Dichlorobenzene
1,4-Dichlorobenzene
1 ,2-Dtehloroethane
CASNO 2
107-13-1
7440-38-2
7440-39-3
71-43-2
111-44-4
7440-43-9
75-15-0
58-23-5
57-74-9
108-90-7
67-66-3
1333-82-0
95-46-7
106-39-4
106-44-5
94-75-7
96-50-1
106-46-7
107-08-2
Regulatory
level (mg/L)
5.0
5.0
100.0
0.07
0.05
1.0
14.4
0.07
0.03
1.4
0.07
5.0
1C.O
10.0
10 0
1.4
4.3
10.8
0.40
-------
TABLE IV-1.-TC CONSTITUENTS AND REGULATORY LEVELS PROPOSED JUNE 13, 1986-Continued
HWNO'
D032«»«—.»«-«—.«"««Mw.««""*— •"*•"•••"•"•"••""""•*""****""" ""*
rwu -j ... ...M.«..».M««»»«M*«»««*«""»**"|M«
0035«««M«««-«««--«««««*-''«'»----'-"--"**''*-->"">"***M"'"""
D033 !.*«»»«««•»«•«•»•>»»•*'»«••"*« «*•»• *»»•••*•••»"«••••«»"•""
n/jig „„,.«««..«...-«..*.••"•*•«•"«••••"••• *
fVII J ..^...'.t.H.mHW"""""*''""""***"*"*'""*
D010........ ..... . , — '• — •
D045, ._,....-..., ..-„-_»— ..-.- .~ •••••- — ~" •
QQ49 .„«„„.,,...«,..«....•••*—•««•."••«•••""«••—•"•—
^izzzz=i::z::::i::::i::::::i:::=:
fV\CO «*.».«»»»•«••••••••••••••••••
I^Ai7 — ».........*.».•» »,.»•••»"••••"•*•"*•"•""•"••""""'
Constituents
2.4-Dinitrotoluene "'"
Endfin...... .....
Hexachlorobenzene • • —
Hexachloroethane • -
Isobutanol-... • ••— : '
LindaneuIZZ - - • •-
Methoxychtor- •• : •••• — '
Methytene chloride..- - - •"••'
Methyl ethyl ketone:_ .» - -
Nitrobenzene... - - • ""'
Pyridine • -
Selenium... "
1,1,2,2-Tetrachloroethane _ • •• '•
Toxaphene ' " '"
1,1,1-Trichloroethane - - • :; -
1,1 ,2-Trichloroethane ••
Trichtoroethylena.... ••••• r •:'
2,4,5-Trichlorophenol .: • ••••' :
2,4,6-Trichlorephenol — "
2,4,5-TP (Sitvex) • • •
Vinyl chloride » •'• -
CASNO»
75-35-4
121-14-2
72-20-8 .
76-44-2
118-74-.1
87-68-3
67-72-1
78-83-1
7439-92-1
58-89-9
74S9.-97-6
72-43-5
75-09-2
78-93-3
96-S5-3
87-86-5
106-95-2
110-86-1
7762^49-2
7440-22-4
630-20-6
79-34-5
-127-18-4
58-90-2
106-88-3
8001-35-2
71-55-6
79-00-5
79-01-6
95-95-4
88-06-2
93-76^5
75-01-4
Regulatory
level (mg/L)
0.1
0.13
0.003
0.001
0.13
0.72
4.3
36.0
5.0
0.06
0.2
1.4
8.6
7.2
0.13
3.6
14.4
5.0
1.0
5.0
10.0
1.3
0.1
1.5
14.4
0.07
30.0
1.2
0.07
5.8
0.30
0.14
0.05
«EPA Hazardous Waste Code Number.
» Chemical Abstracts Service number.
As explained in section IH.E.2.a.vii,
the Agency does not have sufficient data
to address the formation and toxicity of
hydrolysis products. Therefore, hi
today's rule, the Agency is not
establishing regulatory levels for those
new organic constituents that are
expected to appreciably hydrolyze and
thereby form potentially toxic by-
products. Rather, the Agency expects to
address these constituents in a future
Federal Register notice.
Three of the organic constituents
.urrently regulated by the EPTC may
hydrolyze to a significant extent.
However, due to uncertainties
associated with this mechanism, the
Agency believes that it would not be
prudent to remove these constituents
from regulation on a temporary basis
(i.e., until their hydrolysis products can
be assessed). Therefore, these
constituents [endrin, methoxychlor, and
toxaphene) will continue to be regulated
at the existing EPTC levels in the
interim.
Also, as explained in section HI.E.2.a,
the Agency has concluded that the
steady-state assumption used in the
ground water transport model may not
ba appropriate for all constituents. The
constituents for which a steady-state
solution may not be appropriate are
being deferred from the list of proposed
constituents. EPA will promulgate or
repropose (as warranted) regulatory
levels for these constituents in a'future
Federal Register notice.
3. Final List of Constituents
a. Organic Constituents, the organic
constituents for which the Agency is
today establishing regulatory levels (i.e.,
those that are on the current EP list, .and
those that do not appreciably hydfolyze
and for which a steady-state assumption
is appropriate) are presented in Table
IV-2.
TABLE IV-2.—ORGANIC CONSTITUENTS
TA'BLE IV-2.—ORGANIC CONSTITUENTS—
Continued
EPAHW
, number *
D018
D019
D020
D021
D022
D023
D024 -
DQ25
D016
D027
D028
D029..... ............
0030. ; :..
•D0t2......i..
Contaminant
Carbon tetrachiorids...
Chlordane
Chlorobenzone I
Chloroform......
o-Creso! ;
m-Cresol '•
p-Cresol
2t4-D -.
1,4-Dichlorobenzene .
1,2-Dichloroethane ....
1,1-Dichloroethylene..
2,4-0!nitrotoluene
Endrin •'•
CAS
number2
71-43-2
56-23-5
57-74-9
106-90-7
67-66-3
95-46-7
106-39-4
106-44-5
94-75-7
106-46-7
107-06-2
75-35-4
121-14-2
72^-20-8
EPAHW
number l
D031 .........
D032
D033 «-
D034
D013
Q0^4
D035
D036...;
D037
D039.:
0015
D040
D041 ;....
0042 «...
0017..
, Contaminant
Heptachlor (and its
riydroxide).
Hexachlorobenzene....
Hexachloro-1,3-
tiutadiene.
He«achtoroethane
LJndane •'•••
Me'thoxychlor
Meithyl ethyl ketone,...
Nitrobenzene
Pentachiorophenol,,...
Tetrachloroethylene...
Toxaphsne ;.
Trichloroethylene
2,4,5-Trichloropheno!
2,4,6-TricrHorophenol
2,4,5-TP (SHvex)
CAS
number *
76-44-2
118-74-1
87-68-3
67-72-1
58-89-9
72-43-5
78-93-3
96-95-3
87-86-5
110-86-1
127-18-4
8001-35-2
79-01-6
95-95-4
88-06-2
93-76-5
75-01-4
»Hazardous waste number.
2 Chemical abstracts service number.
b. Inorganic Constituents. Among the
constituents that were proposed for
inclusion in the TC were eight inorganic
constituents that are currently regulated
in the EPTC. BiBqjmse EPACML does not
currently accommodate metallic species,
it cannot be used to predict DAFs for
these constituents. Therefore/the
Agency is today retaining the regulatory
-------
Federal Register / Vol. 55, No. 61 / Thursday, March 29. 1990 / Rules and Regulations 11845
levels for these constituents at their
current levels. When the MINT EQ
model (see III.B.5.C) is available to
accommodate these constituents, the
Agency will reconsider their regulatory
levels and propose new ones, if so
warranted.
B. Selection ofDAFs
The selection of the appropriate DAF
for the constituents addressed in today's
rule is based on the municipal landfill
scenario, as proposed. However, based
on comments on fate processes that •
were not appropriately considered in the
model, several constituents have been
omitted from the proposed list of
constituents— specifically, those that
may hydrolyze to more than a negligible
extent and those for which the steady-
state assumption may not be
appropriate.
For the remaining constituents; the
Agency believes that a DAF of 100 is
appropriate for establishing regulatory
levels in today's rule. The basis for this
conclusion is explained in Section
C. Analytical Constraints
The regulatory levels for the
compounds proposed lor inclusion in the
TC span approximately five orders of
magnitude (i.e., from the low parts per
billion to 100 parts per million). The
calculated regulatory levels for three of
these compounds (2,4-dinitrotoluene, .
hexachlorobenzene, and pyridine) are
below the concentrations measurable
using currently available methods.
EPA believes that the appropriate
way to deal with a calculated regulatory
level that is below the analytical
detection limit is to use (for the
regulatory level) the lowest level of
detection that can be attained. The
lowest level of a particular chemical
that can be reliably measured within,
acceptable limits 'of precision and
accuracy under routine laboratory
operating conditions is that chemical's;
"quantitation limit," A quantitation limit
is determined through such studies as
method performance evaluations.
If data from interlaboratory studies
are unavailable, quantitation limits are
estimated based on the detection limits
and an estimated multiplier that
represents a practical and routinely
achievable level with relatively high
certainty that the reported value is
reliable. EPA proposed to use a value of
. five times the analytical detection limit
as the quantitation limit and to set the
regulatory level at the quantitation limit
for those compounds for which the
calculated regulatory level is below the
quantitation limit, and interlaboratory
. studies were not available. .. . ;
Because TCLP extracts are aqueous in
nature, the quantitation limits used in
this rule are based on the presence of
these compounds in a water matrix. The
Agency received many comments on the
use of the quantitation limit as the
regulatory level for the three compounds
with health-based thresholds below that
level. Most commenters expressed
concern that quantitation limits based
on analysis of the constituent in a water
matrix may not be achievable in more
complex samples. The comments
discussed potential complications that
could hamper analysis of various kinds
of wastes and recommended that EPA
Work toward determining actual
quantitation limits on real wastes.
The Agency agrees that the ability to
achieve the quantitation levels listed in
the proposed rule is strongly influenced
by the type of waste that is being
analyzed. However, determination of a
matrix-dependent quantitation limit
would require analysis of a wide variety
of wastes. EPA believes that it would be
impractical to perform such waste-
specific analyses at this time. Therefore,
EPA has'chosen to use the proposed
definition (i.e., five times the method
detection limit) for the quantitation
limit;
A number of commenters addressed
the issue of the generic multiplier used
to derive the quantitation limit. Several
commenters recommended using 10 to
25 times the detection limit as the
•regulatory level, while a few
commenters supported setting the
regulatory level at the detection limit
itself, to provide what they believe
would be greater environmental
protection.
The Agency is working to improve the
sensitivity of analytical methods to
provide increased protection of human
health and the environment. Analytical
detection limits are, by definition, not
routinely achievable under average
laboratory conditions. Thus, a
regulatory level set at the detection limit
would be difficult for the Agency to
enforce and would make it difficult for
the regulated community to demonstrate
compliance. To provide a consistently
enforceable regulatory limit while
providing assurance that those wastes
that clearly pose hazards are subject to
subtitle C requirements, the Agency will
set the regulatory level at five times the
detection limit. The Agency has a high
degree of confidence in setting the
regulatory level at the quantitation limit
(i.e., five times the detection limit)
because other programs within the
Agency have successfully used this' .
method in the past to set regulatory
levels (e.g., the Contract Laboratory
Program under the Superfund Program).
. Comments on the use of the
quantitation limit are addressed more
extensively in the testing methods
background document.
D. Final Regulatory Levels
The regulatory levels being
•promulgated today are equal to the
product of each constituent's toxicity
threshold and the DAF or the
quantitation limit. These regulatory
levels are presented in Table IV-3.
These levels are designed to identify
wastes that clearly pose a hazard and
define those wastes as hazardous.
However, it should be noted that wastes
that do not exhibit this characteristic
(e.g., result in TCLP levels that are less
than the regulatory levels) are not
necessarily nonhazardous and may be
listed as a hazardous waste or become
hazardous under other hazardous waste
characteristics.
TABLE IV-3.—?TOXICITY CHARACTERISTIC CONSTITUENTS AND REGULATORY LEVELS
EPA HVV number >
D004
D018 ,...;..;
D006 ' "
D019.........;.; ; ;._
D020..........
D021. ;„....-.; „ ,'; .
D022
D007.......;. _.. . '
0023_ ;.... ... ; •-.••'••
Constituent
Arsenic
Barium ..'„.. -
Benzene
Carbon tetrachloride
Chlordane ...:„.. ,.... • ' '
Chlorobenzene
Chromium
o-Ccesol • • .
CAS
Number2
7440-38-2
7440-39-3
71-43-2
7440-43-9
56-23-5.
57-74-9
108-90-7
7440-47-3
95-48-7
Regulatory
level (mg/L)
5.0
100.0
0.5
1.0
0.5.
'0.03
100.0.
6.0
5.0
1 ' • « 200.0
-------
11848 Federal Register / Vol. 55. No. 61 / Thursday. March 29. 1990 /Rules and Regulations
TABLE IV-3.—Toxicrrv CHARACTERISTIC CONSTITUENTS AND REGULATORY LEVELS—Continued
EPA KW number'
D025,,...».....,.«..M.._.«..-.. ...... .- -
fV)9A «>..•...»«••>•*»•.»••»
D016«ww«.w!«w»*«Mt*««t»««.««««« ............... « "•"
D028,,,....,...,..,.,.,.,.,,.... - —
D030~~~~. , •—• »
D012 -1111111- ,„.......,.....- ,...-.....- „_....._,......-...
0031 ^«TO(,».™ ...«.»».—.....«..- -••••• "• — •
{5O33 ~ • »•»*•••• »I»III<>* .,...«».—.....«.»•••"•*•
coos,.,™..,..™. . •
0009™".!-......"". •
fV\1A mmn....nnT-t—
UU*^W».«»M««»««"'-«"*»«*«»"""""1"**""""**""'*"' «•««"
ryyiC * „ ~.....,*™.»., »
l^/t>9«*«9t »t**»)*IHt» !*«»*•*•* ••"*»«•""**••*""••*'""*" — «•«*«"••*»"""""""
D037""T"dZ™Z!!!lJ. —
fWlJt ..,,•,. i»»»»><*»»'*»"***"»*
rv\f n .»„«»,,,...»••••*••«"••»«"••"«•"••••"••
D01 1 .1.™- ™ .
fWlQ . . ..-.,.«.«.«..•.».*••»**•*•••••••*••••'
fVUA ••••.«*•••
D041«««««««..»«««««»«««»»»»-»»—»«»»"— ••• — — — •"•""*
Constituent
m-Cresof — .,....._.-. ; ;
p-Crosol - - — - • :
Cresol ••••—; .™v :
2,4-D « •- « :
1.4-Dtchtorobenzerie — - - • •
1,2-Dichloroethane -...: — .". - • ; •••'••
1.1-Dichloroethylene _. _ ••«
2,4-Dinitrotoluana ~ • ;
Endrin ; ..........
Heptachlor (and its hydroxide) :
Hexachlorobenzena — - - • •
Hexachloro-1, ^butadiene-., - - ...........
Hexachtoroethane..:. _•.
Undane.._ '
Mercury ..... - ~ - *
Methyl ethyl ketone -- ;
Nitrobenzene..- - •••
Pentachtorophenol • -
f£um— ^.••:::z::::::::::::::::::::::::::::::::::::
Tetrachloroethylene : -
Trichloroethylene - •'•
2.4.S-Trich)orophenol •• - ••
2.4.6-Trichloropheno1 - - ~
2.4,5-TP (Sflvex) - • • • ""
CAS
Number2
108-36-4
106-44-5
94-75-7
106-46-7
107-06-2
75-35-4
121-14-2
72-20-8
76-44-8
118-74-1
87-68-3
67-72-1
7439-92-1
. 58-89-9
7439-97-6
72-43-5
78-93-3
98-95-3
11Q-86-1
7782-49-2
7440-22-4
127-18-4
8001-35-2
79-01-6
88-06-2
93-72r1
75-01-4
Regulatory
level (mg/L)
« 200.0
•« 200.0
« 200.0
10.0
7.5
0.5
0.7
'0.13
0.02
0.008
3 0.13
0.5
3.0
5.0
0.4
0.2
10.0
200.0
2.0
'1000
3 5.0
1.0
5.0
0.7
0.5
0.5
4000
2.0
1.0
0.2
«Hazardous wasta number.
* Chemical abstracts service number.
» Quanttation limit Is greater lhan the calculated r
« H
-------
Federal Register / Vol. 55, No. 51 / Thursday. March 29, 1990 / Rules and Regulations 11847
administer and enforce the RCRA
program within the state (see 40 CFR
part 271 for the standards and
requirements for authorization).
Following authorization, EPA retains
enforcement authority under sections
3008, 7003 and 3013 of RCRA, although
authorized states have primary
enforcement responsibility. Prior to
HSWA, a state with final authorization
administered its hazardous waste
program entirely in lieu of the federal
program. The federal requirements no
longer applied in the authorized state,
and EPA could not issue permits for any
facilities in a state'that was authorized
to issue permits. When new, more
stringent federal requirements were
promulgated or enacted, the state was
obligated to enact equivalent authority
within specified time frames. New
federal requirements did not take effect
in an authorized state until the state
adopted the requirements as state law.
In contrast, under section 3006(g) of
RCRA, 42 U.S.C. 6926(g), new
requirements and prohibitions imposed
by HSWA take effect in authorized
states at the same time that they take
effect in nonauthorized states. EPA is
directed to carry out those requirements
and prohibitions in authorized states,
including the issuance of permits, until
the state is granted authorization to do
so. While states must still adopt HSWA-
related provisions as state law to retain
final authorization, the HSWA
requirements are implemented by EPA
in authorized states in the interim.
Today's rule is promulgated pursuant
to RCRA section 3001(g) and (h). These
provisions were added by HSWA.
Therefore, the Agency is adding the
requirement to Table 1 in § 271.1Q),
which identifies the federal program
requirements that are promulgated
pursuant to HSWA and that take effect
in all states, regardless of their
authorization status. States may apply
for either interim of final authorization
for the HSWA provisions identified in
Table 1, as discussed in the following
section of this preamble.
2. Effect on State Authorization
As noted above, EPA will implement
today's rule in authorized states until
they modify their programs to adopt
these rules and the modifications are
approved by EPA. Because the rule is
promulgated pursuant to HSWA, a state
submitting a program modification may
apply to receive either interim or final
authorization under section 3006(g}(2) or
3006(b), respectively, on the basis of
requirements that are substantially
equivalent or equivalent to EPA's. The
procedures and schedule for state
program modifications for either interim
or final authorization are described in 40
CFR 271.21. It should be noted that all
HSWA interim authorizations will
expire January 1,1993 (see 40 CFR
271.24{c)).
40 CFR 271.21(e)(2) requires that
states with final authorization must
modify their programs to reflect federal
program changes, and they must
subsequently submit the modifications
to EPA for approval. The deadline for
state program modifications for this rule
is July 1,1991 (or July 1,1992, if a state
statutory change is needed). These
deadlines can be extended in certain
cases (40 CFR 271.21(e)(3)). Once EPA
approves the modification, the state
requirements become subtitle C RCRA
requirements. States with authorized
RCRA programs may already have
requirements similar to those in today's
rule. These state regulations have not
been assessed against the federal
regulations being promulgated today to
determine whether they meet the tests
for authorization. Thus, a state is not
authorized to implement these
requirements in lieu of EPA until the
state program modification is approved.
Of course, states with existing standards
may continue to administer and enforce
their standards as a matter of state law.
In implementing the federal program,
EPA will work with states under
• cooperative agreements to minimize
duplication of efforts. In many cases,
EPA will be able to defer to the states in
their program implementation efforts,
rather than take separate actions under
federal authority.'
States that submit their official
applications for final authorization less
than 12 months after the effective date
of these standards are not required-to
include standards equivalent to these
standards in their application. However,
the state must modify its program by the
deadline set forth in § 271.21(e). States
.that submit official applications for final
authorization 12 months after the
effective date of these standards must
include standards equivalent to these
standards in their application. The
process and schedule for final state
authorization applications is described
in 40 CFR 271.3.
B. Integration of Today's Final Rule
with Existing EPTC
As explained above, because this rule
is promulgated pursuant to HSWA, it
will be-effective six months from today
in both authorized and unauthorized
states and will be implemented by EPA
until states receive authorization for this
rule. Thus, beginning on the effective
date, large quantity generators that
generate TC waste in all states are
responsible for complying with the.
appropriate requirements. However, the
rule promulgated today also revises an
existing RCRA rule defining hazardous
wastes that authorized states have been
implementing for some time. The two
principal changes in the rule are the
revision to the leaching procedure, by
replacing the EP with the.TCLP, and th-=
addition of constituents for which the
leachate will be analyzed. The
discussion below and Table V-2
describe how state implementation of
the existing EPTC will be integrated
with EPA implementation of the TC as
promulgated today.
1. Facilities Located in Authorized
States
There are three types of facilities
located in authorized states which are
affected by today's rule: facilities which
are already operating under a RCRA
permit, facilities which are already
operating under interim status, and
facilities which are subject to RCRA
permit requirements for the first time as
a result of today's rule. Permitted and
interim status facilities can also be
affected by today's rule in three distinct
ways: (1) The facility may already be
managing wastes that are hazardous
under the existing EPTC, (2),the facility
may already be managing wastes that
are hazardous under the existing EPTC
but which also exhibit the toxicity
characteristic for a new constituent(s)
under today's rule (and thus the waste
would have a new waste code), or (3)
the facility may be managing' a solid
waste which is newly subject to
regulation as a result of today's revision
pf the TC. Table V-2 summarizes the
initial filing requirements and applicable
standards for each category of facility.
-------
Federal Register / VoL 55. No. 61 / Thursday, March 29. 199Q / Rules
———•••••a*i*mm****i^*mm^mm^^m^^mmi^*mmi^^*B*™**&mittmittam^*^^*****i^*i*^^^^^^^^^^^^^
1114*
TABLE V-2.—INTESRATJON OF TC WITH EXISTING EPIC
Status of Stats authorization
!, Authorized State ™..~,;™~...™»— — —
N •uuttorbed State—
. B — •
Facility status '
A. Permitted — ,.
8. Interim Status
C. Newly-regulated....
A. Permitted ;
8. Interim Status —
ewl ulated
C.Newly-reg ate
Type of waste '
. Regulated EPA
waste w/no new
consfJtuenHs under
revised TC.
2. Regulated EP waste
w/new constituents.
3. -previously :
unregulated waste or.
-Already regulated
unit. !
—Prevtousty
unregulated unit
1. Regulated EP waste
' w/no new
constituents under
revised TC.
2. Regulated EP waste
w/nsw consfltuerrts
under revised TC.
3. Previously
•unregulated -waste. •
1. Regulated EP waste-
w/no new
constituents under
revised TC.
2. Regulate EP waste
w/new constituents
under revised TC.
3. Previously
unregulated waste iir.
-Already regulated
unit.
-Previously
•unregulated unit
9. Regulated EP waste
' ' w/no new
constituents under
revised TC.
2. Regulated EP waste
w/new constituents
under revised TO.
3. Previously
unregulated waste.
Wnsttofile
NA '.
Class « permit
•modification under 40
CFH 270.42.
Class 1 permit
modification -under 10
CFR 27O.42.1
.Revised Part A under .
40 CFR. 270,72.
Revised Part A tinder
40 CFR 270.72.*
Part A and 3010 under
40 €FR 270.7'
-------
Federal Register / Vol. 55, No. 61 / Thursday. March 29, 1990 / Rules and Regulations 11845
requirements for management of these
wastes.
Some permitted and interim status
facilities in authorized states will be
managing wastes which will become
hazardous as a result of today's rule.
These facilities must also submit permit
modifications or part A permit
application revisions to EPA. However,
because these wastes were previously
unregulated under RCRA, they also
were not regulated under the authorized
state program. As a result, if these
wastes are in a previously unregulated
unit, they will be subject to the self-
implementing Federal standards for
hazardous wastes management at 40
CFR part 265 until permit issuance (for
interim status facilities] or modification
(for permitted facilities). After permit
issuance or modification, the Federal
permitting standards at 40 CFR part 264
will apply to these wastes (or the state
permitting standards if the permit is
ultimately issued or modified by a state
authorized for the TC). However, if the
wastes are at a permitted facility in a
unit that is already regulated, that unit
will continue to comply with the
applicable 40 CFR part 264 (or state
equivalent) standards.
Facilities in authorized states which
are newly subject to RCRA permit
requirements as a result of today's rule
must obtain an EPA identification
number and submit their part A permit
application and section 3010 notification
to EPA in order to obtain interim status
(see 40 CFR 270.70). Such facilities are
subject to regulation under 40 CFR part
265 until a permit is issued by EPA or a
state authorized for the TC.
2. Facilities Located in Unauthorized
States
There are also three types of facilities
located in unauthorized states which are
affected by today's rule: already
permitted facilities, facilities operating
under interim status, and facilities
newly subject to RCRA permit
requirements under today's rule. As in
authorized states, some of the permitted
and interim status facilities have been
managing EPTC wastes.
For interim status and permitted
facilities which have been managing
EPTC wastes that will exhibit no new
constituents as a result of ihe
replacement of the EP with the TCLP
and the addition of constituents to the
TC, there will be no waste code
changes. Accordingly, such facilities do
not need to submit permit modifications
or revised permit applications to EPA
and will continue to be subject to the
applicable federal standards for
hazardous waste management.
Facilities which have been managing
EPTC wastes which exhibit the toxicity
characteristic for new constituents as a
result of today's changes to the TC must
notify EPA of the waste code changes
for its TC wastes. Permitted facilities
must submit permit modifications to
EPA as required under 40 CFR 270.42
that reflect the new wastes codes.
Interim status facilities must submit
revised part A permit applications in
accordance with 40 CFR 270.72. These
facilities must continue to comply with
the applicable federal standards for
hazardous waste management.
Permitted and interim status facilities
which manage waste that is newly
defined as hazardous waste as a result
of today's rule must also submit permit
modification requests or part A permit
application revisions to EPA. Facilities
must manage these wastes-in
accordance with 40 CFR part 265 or 40
CFR part 264 until permit modification
or issuance, depending on whether the
waste is managed in a newly regulated
or previously regulated unit.
Facilities which are newly subject to
RCRA permit requirements as a result of
today's rule must get an EPA
identification number and a part A
permit application to EPA in order to
obtain interim status. Such facilities are
subject to regulation under 40 CFR part
265 until a permit is issued.
C. Notification
Pursuant to RCRA section 3010, the
Administrator may require all persons
who handle hazardous wastes to notify
EPA of their hazardous waste
management activities within 90 days
after the wastes are identified or listed
as hazardous/This requirement .may be
applied even to those generators,
transporters, and TSDFs who have
previously notified EPA with respect to
the management of other hazardous
wastes.
In the June 13,1986, Federal Register
notice, EPA proposed to waive the
notification requirement for persons
who manage TC wastes and have
already (1) notified the Agency that they
manage other hazardous wastes and (2)
received an EPA identification number.
EPA has decided to waive the
notification requirement as proposed.
The Agency believes that, given the vast
scope of the TC rule, a notification
requirement for persons already
identified within the hazardous waste
management universe is unnecessary.
EPA is not waiving the notification
requirement for TC waste handlers that
have neither notified the Agency that
they manage hazardous wastes nor
received an EPA identification number.
Those persons must notify EPA no later
than June 27,1990 of these activities
pursuant to section 3010 of RCRA.
Notification instructions are set forth in
45 FR 12746, February 26,1980.
D. Permitting
Currently permitted facilities that
manage TC wastes must submit Class 1:
permit modifications if they are to
continue managing the newly regulated
wastes in units that require a permit.
The facilities must obtain the necessary
modification by the effective date of the
rule, or they will be prohibited from
accepting additional TC wastes.
. Interim status facilities that manage -
TC wastes in units that require a permit
must file an amended part A permit :
application under 40 CFR 270.10(g) if
they are-to continue managing newly
regulated wastes. The facilities must file
the necessary amendments by the
effective date of the rule, or they will not
receive interim status with respect to'the
TC wastes (i.e., they will be prohibited
from accepting additional TC wastes
until permitted).
Newly regulated facilities (i.e.,
facilities at which the only hazardous'
wastes that are managed are newly
regulated TC wastes) must qualify for.
interim status by the compliance date of
the rule in order to continue managing
TC wastes prior to receiving a permit;
Under 40 CFR 270.70, an existing facility
may obtain interim status by getting an
EPA identification number and.
submitting a part A permit application.
To retain interim status, a newly-
regulated land disposal facility must
submit a part B permit application
within one year after the effective date
of the rule and certify that the facility is
in compliance with all applicable ground
water monitoring and financial
responsibility requirements (see RCRA
section 3005(e)(3)).
EPA recently promulgated
amendments to the procedures for
permit modifications for treatment,
storage, and disposal facilities (see 53
FR 37934, September 28,1988). The
following discussion assumes
implementation in accordance with the
new rule. EPA Will implement the TC by
using the new permit modification
procedures, consistent with EPA policy
(see 53 FR 37933, September 28,1088). :
Under the new regulation in § 270.42, ;
there are now three classes of permit.
modifications with different submittal
and public participation requirements
for each class. In § 270.42(g), which ;
concerns newly listed or identified'
wastes, a permitted facility that is "in
existence" as a hazardous waste facility,
for the newly listed or identified waste .
on the effective date of the notice must
-------
11B50 Federal Register / Vol. SS, No. 61 / Thursday. March 29.
submit a Class 1 modification by that
date. Essentially, this modification is a
notification to the Agency that the
facility is handling the waste. As part of
Ihe procedure, the permittee must also
notify the public within 90 days of
aubmittal to the Agency.
Next, within 180 days of the effective
date, the permittee must submit a Class
2 or 3 modification to the Agency. A
permittee may submit a Class 2
modification if the newly regulated
waste will be disposed in existing TSD
units and will not require additional or
different management practices from
those authorized in the permit A Class 2
modification requires public notice fay
the facility owner of the modification
request, a 60 day public comment
period, and an informal meeting
between the owner and the public
within the 60 day period. The rule
includes a "default provision," so that
for Class 2 modifications, if the Agency
does not make a decision widiin 120
days, the modification is automatically
authorized for 180 days. If the Agency
does not reach a decision by the end of
that period, the modification is
permanently authorized. If the newly
regulated waste requires additional or
different management practices, a Class
3 modification is required. The initial
pOblic notification and public meeting
requirements are the same as for Class
2. However, after the end of the public
comment period, the Agency will
develop a draft permit modification,
open a public comment period of 45
days and hold a public hearing.
E, Compliance Dale
The Agency is promulgating two
different compliance dates for two
different categories of TC waste
generators: (1) All generators of greater
than 100 and less than 1,000 kg/month of
hazardous waste (small-quantity
generators) must come into compliance
with subtitle C requirements for
management of their TC waste within
one year from today; and (2) all
generators of 1,000 kg/month or more of
hazardous waste andTSDFs are
required to comply with all subtitle C
requirements for TC wastes within six
months from today, on the effective date
of the rule. Thus the EFTC remains in
effect .until six months after today's date
for large quantity generators andTSDFs,
andreniains in effect for 12 months after
today's date for small quantity
generators. ThegeneralOT quantity
refers to all of a generator's hazardous
waste, not fust newly hazardous TC
waste.
Further discussion of the Agency's
reftvooa for promulgating an extended
compliance date for small-quantity
generators is provided in section IILK of
this preamble. In summary, the Agency
believes that allowing an additional six
months for small quantity generators^ to
come into full compliance with the TC
will serve two purposes. First, it will
allow tKe Agency time to educate small
quantity generators on the RCRA rules
while, at the same time, allowing the
Agency to focus immediate
implementation efforts on large volumes
of hazardous waste. Second, it will
provide the necessary time for small
quantity generators to comply with
subtitle C requirements as a result of the
TC.
VL Regulatory Requirements
A. Introduction
This portion of the preamble discusses
the analyses required by Executive
Order No. 12291 and the Regulatory
Flexibility Act. The Agency is required
under the Executive Order to estimate
the costs, economic impacts, and
benefits of "major" rules by conducting
a regulatory impact analysis (RIA).
Recognizing the potential of the Toxicity
Characteristic {TC] rule to affect a broad
spectrum of American industry, EPA
prepared an RIA comparing .several
regulatory alternatives. Based on the
results of this analysis, the Agency
concluded that this final regulation is a
major rule. Section VLB presents the
methodology and results of the RIA.
The Regulatory Flexibility Act
requires fee Agency to assess small
business impacts resulting from
regulations. The analysis of small
business impacts indicated that the TC
rule would not have a significant impact
on small businesses, and therefore a
formal regulatory flexibility analysis
was not prepared. Section VLC
addresses potential effects on small
businesses.
The Agency received many comments
on the RIA for the June 13,1988
proposal. A summary of comments,
along with Agency responses, is
included as section YI.D. Section VI.E
discusses requirements under the
Paperwork Reduction Act •
Details of the regulatory impact
analysis and small business analysis are
available in the RIA document for the
final rule {Ref. 8). This final rule was
submitted to die Office of Management
and Budget for review as required by
E.O. No. 12291,
B. Regulatory bnpacl Analysis
1. Executive Order No. 12291
Executive Order No. 12291 requires
EPA to assess the effect of Agency
actions during the development of
regulations. Such an assessment
consists of a quantification of the
potential costs, economic impacts, and
benefits of a rule, as well as a
description of any beneficial or adverse
effects that cannot be quantified in
monetary terms. In addition, Executive
Order No, 12291 requires that regulatory
agencies prepare a regulatory impact'
analysis (RIA) for major rules. Major
rules are defined as those likely to result
in (1) an annual cost to the economy of
$100 million
-------
Federal Register / Vol. 55. No. 61 / Thursday, March 29, 1990 / Rules and Regulations f 11851-
the wastes became hazardous. These
incremental costs were aggregated to
estimate national costs of the rule.
Economic impacts on facilities were
based on a comparison of facility
compliance costs with costs of
production and cash from operations.
The potential for facility closures .was
also examined.
Benefits, like costs, were based on
required changes in waste management
practices. Benefit measures included
human health risk reduction, resource
damage reduction, and cleanup costs
avoided. Facility-level benefit estimates
were aggregated to obtain national
benefits.
Section VI.B.3, below, presents the
methodology used to estimate costs,
economic impacts, and benefits. It also
briefly describes the sensitivity analyses
that were conducted to determine the
significance of key analytical
assumptions; these sensitivity analyses
are discussed in more detail in the RIA.
Limitations of the analytical approach
(e.g., assumptions which are likely to
overstate, understate, or create
uncertainty in results) are discussed in
the RIA. Results of the analysis of costs,
economic impacts, and benefits are
provided in section VI.B.4.
3. Methodology
The methodology for the RIA is
presented in several parts. First, the
procedure for identifying wasted and
facilities affected by the TC is
discussed. Next, the development of
national cost estimates is presented. The
section on economic impact
methodology describes the criteria used
in gauging impacts on the regulated
community. Following that is a section
that presents several alternative
measures of benefits of the rule. The last
section describes the methodology for
analysis of used oil.
a. Determination of Affected Wastes
and Facilities. The first step in
estimating the impacts of the rule was to
determine which wastes and facilities
would be affected by the rule, based on
waste characteristics, quantities, and
management practices. No single data
source contained all of this information,
and none of the data were facility-
specific. Therefore, the Agency
assembled aggregated data (e.g., by
industrial sector) from separate sources
and used it to draw inferences on
facility-level impacts.
Data on waste characterization and
volume came primarily from a series of
TC industry studies. (Ref. 19 through 29)
These studies were conducted for major
industrial categories identified as likely
to generate significant quantities of TC
wastes; other sectors, generating smaller
quantities of potentially affected waste,
were not addressed. Standard Industrial
Classifications (SICs) for the industrial
sectors studied range between the two-
digit and four-digit levels. The industries
profiled are shown in Table VI-1.
TABLE VI-1.—POTENTIALLY AFFECTED IN-
DUSTRIES CONSIDERED IN RlAs FOR
THE PROPOSED AND FINAL TC RULES
Industry
Textile Mills 2
Lumber and Wood
. Products.2
Pulp and Paper 2 ..
Printing and
Publishing.
Plastics Materials
and Resins.2
Synthetic
Rubber.2.
Synthetic Fibers.2 ..
Pharmaceuticals.2..
Soaps and Other
Detergents.
Surface Active
Agents.
Paints and Allied
Products.
Organic
Chemicals.*
Agricultural
Chemicals.
Petroleum
Refining.2
Miscellaneous
Petroleum and
Coal Products.2
Rubber and
Miscellaneous
Plastics
Products.2
Non-Ferrous Wire
Drawing and
Insulation.
. Machinery and
Mechanical
Products.
Pipelines, except
Natural Gas.2
Electrical Services ..
Wholesale
Petroleum
Marketing.2
SIC>
22
2421,2499
261, 262, 263,
266.
27
2821 ... .
2822
2823, 2824
283
2841
2843
2851
2865,2869
2879
2911
2992
30
3357
34 through 39 ..
461
4911
517.......
Pro-
posed
X
X
X
x
x
X
X
x
X
X
Final
x
X
X
x
x
X
x
X
X
X
X
x
X
x
x
x
'SICs listed are those defining the group consid-
ered in this analysis. SICs given at the two-digit or
three-digit SIC level indicate that the analysis applies
to all four-digit SICs contained within the broader
category
2 Included in detailed quantitative analysis for the
final RIA.
The industry studies provided data
including waste type (wastewater,
sludge, solid process residual, or organic
liquid), waste quantity, constituent
concentration ranges and distributions,
and number of generating facilities. The
data in the studies were based primarily
on EPA's effluent guidelines reports,
supplemented by best engineering
judgement and data received in
comments on the proposed rule or in
follow-up correspondence (Refs. 30 and
31). Most of the wastes which were
included were related to wastewater
treatment; there was relatively little
data on process residuals. Wastes which
were already hazardous by virtue of a
listing or characteristic (e.g., the EPTC)
were not included. Due to lack of data,
certain,types of wastes were not
included in the analysis'(e.g.,
contaminated soil, off-spec products, ,
contaminated debris).
It is particularly difficult to predict the
behavior of oily wastes in the TCLP test.
For the purpose of deriving upper bound
estimates of costs, economic impacts; ,
and benefits, one assumption that EPA
adopted was that oily non-liquid wastes
would not present filtration problems in
the TCLP (i.e., that the oily phase passes
through the filter'and hazardous
constituents in the oil phase leach to the
test extract) and that if extract
concentrations exceeded regulatory
levels, these wastes would fail the TC.
As a basis for lower bound estimates for
costs; economic impacts and benefits,
the Agency assumed that no oily wastes
will be caught by TC regulation because
the oily phase (and corresponding high
levels of toxic constituents) would not
filter through to the extract in the TCLP.
Due to the lack of facility-specific
waste generation data, certain
assumptions had to be made to derive
the quantity of each wastestream per
facility. First, potentially affected
facilities within each industrial sector
were split between small (with less than
50 employees) and large (with 50
employees or more) facility size
categories based on 1982 Census of
Manufacturers data on the number of
facilities by size category. (The 1982
Census data were the most recent
available.) Second, the total quantity of
potentially affected waste was
distributed between small and large
facilities based on Census of
Manufacturers data on the value of
shipments for the small and large size
categories. Using the distribution of
-facilities and of total waste quantity
between small and large size categories,
EPA estimated wastestream quantity
per facility for small and large facilities.
EPA conducted a sensitivity analysis
in order to test the sensitivity of results
to the assumed distribution of wastes
based on value of shipments. Since the
division of waste quantities based on
value of shipments resulted in most
waste being generated by large
facilities, EPA tested the alternative
assumption that waste quantities were
split evenly between the large and small
facility size categories in each industry.
(Results of sensitivity analyses are
presented in section VI.B.4.)
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11B52 Federal Register / VoL 55. No. 61 / Hmrsday. March 29. 1990 /
Baseline management practices ti.e.,
management practices in the absence of
tho regulation) were derived primarily
from the Screening Survey of .Industrial
subtitle D Establishments. (Ref.16.) This
survey provided information on the
percent of facilities, by industrial sector,
which manage non-hazardous wastes
on-site in landfills, surface
Impoundments, waste piles, and land
application units. Other baseline
management practices were not
specifically identified in the survey;
therefore, EPA had to use knowledge of
potentially affected TC wastes to
identify these other practices and
estimate die percentage of facilities
using them.
In the case of non-wastewaters, the
other practices considered included
management in off-site landfills and
land application units. For wastewaters,
the other baseline practices included
management in tanks AS part of a
wastewater treatment system, direct
discharge under a NPDES permit, or
indirect discharge to a Publicly Owned
Treatment Works. These other
wastewater management practices were
assumed to be permissible under
subtitle C; therefore It was-assumed that
facilities using these practices for
wastes which were identified as
hazardous by the TC would not be
affected by the TC rule. EPA examined
the sensitivity of results to this
assumption by assuming, alternatively,
that all wastewatera were managed on
site in subtitle D surface impoundments.
For organic liquids, EPA determined,
based on the Office of Solid Waste's
Industry Studies Database, that the most
likely baseline management practices
were recycling and burning. EPA
assumed that incremental management
costs for these wastes would not be
significant and therefore did not include
the wastes in the analysis.
By combining the waste
characterization and volume data with
the management practice data, it was
possible to estimate, by industrial
sector, the amount of waste and the
number of facilities potentially affected
bytheTC,
In order to determine the quantity of
each wastestream which would be
affected by the TC, the regulafory levels
for constituents in the waste were
compared with the estimated
concentration distributions, derived
from the TC industry studies, for
constituents in the waste leachate. The
constituent which caused the largest
percentage of the wastestream to fail the
TC was designated as the "cost-driving"
constituent, and the quantity exhibiting
Ihe TC due to the presence of that
constituent was used as the affected
quantity. EPA tested the sensitivity of
results to the assumption that waste
would fail for a single driving
constituent by adding the percentages
failing for all constituents {up to 100
percent).
Due to the lack of facility-specific
data, it was assumed that the
percentage of facilities affected by the
TC for a particular wastestream would
equal the percentage of the total waste
failing the TC. (For example, if 25
percent of a wastestream failed, it was
assumed that 25 percent of the facilities
generating the viaste would be affected
and that all of the wastestream at each
affected facility would fail.) In order to
test the importance of this assumption,
EPA adopted two alternative
assumptions as sensitivity analyses: for
any percentage of waste failing (except
for 0 and-100 percent, where clearly no
facilities or all facilities would be
affected), the percentage of facilities
affected would be 10 percent or.
alternatively, 80 percent.
The effects of potential production
process changes in response to the rule
were not addressed.
b. Cost Methodology. EPA estimated
both the social costs and the compliance
costs of the final rule. Social costs do
tfot include transfer payments between
different parties within society {i.e., they
do not include tax payments or above-
. average profits); the social costs
therefore represent the real resource
costs imposed by the rule on society as
a whole. Compliance costs, which
include the effects of taxes and above-
average profits, more accurately reflect
the effect of the rule on particular
entities within society.
1. Social Costs
EPA estimated the national social
costs of the final rule by calculating
before-tax incremental management
costs for affected wastes at model
facilities and then summing the facility
costs across industrial sectors.
Before-tax incremental costs were
calculated by subtracting baseline
management costs from post-regulatory
costs. Baseline management practices
were determined as discussed
previously. Post-regulatory management
practices were developed based on
waste types and quantities; the least-
cost practice among those feasible for a
waste was chosen as discussed below.
The post-regulatory practices did not
include potential waste treatment
practices under the land disposal
restrictions program since land disposal
restrictions requirements for TC wastes
will not come into effect until after the
TC rale is promulgated. Possible post-
regulatory management practices, as
well as'baseline practices, for TC
wastes are shown Jin Table VI-Z
TABLE VJ-2.—BASELINE AND Post'
REGULATORY MANAGEMENT PRACTICES
: ]
Waste type
Wastewater
Non-
wastewator.
Organic liquid —
BK90line
pi8ctic6
On-site Subtitle
D sutfaca
impoundment
or
Practice
permissible
under
Subtitle.1.
OfWHeSubtate
OljndfHIor
land
application
twit or off-site
SuMffiaD
landfill.
Burning,
recycling.
Post-regulatory
practice <
On-site tank
exempt from
Subtitle C,
Subtitle C
surface
Impound-
ment.1
Same as
baseline.3
On-sito or off-
site Subtitle
C landfill or
land
application
unit
Sams' as
baseline.3
1 Dilution and deep-well .injection were ateo con-
sidered as posUeguJatory practices but were found
to be more expensive than tenk management
'Includes management hi Subtitle C-exempt
tanks, direct discharge' under a NRDES germs, at
indirect discharge to n Publicly Owned Treatment
3 Since the post-regulatory practice was the same
as the baseline practice, the -ule would not affect
management at these irastes.
To estimate before-tax baseline and
post-regulatory ccists for wastes, EPA
first estimated the cost per metric ton
for the different o:n-site and off-site
waste management practices. Before-tax
costs for on-site management units
include operation and maintenance
(O&M) and capital costs. O&M costs are
incurred annually for operation and
maintenance of waste treatment or
disposal units. Capital costs include
costs for construction of the unit and for
depreciable assets; these costs, which
assumed an average operating life of 20
years, were restated as annual values
by using a capital! recovery factor based
on a discount rate of three percent.
RCRA-related costs such as personnel
training, financial assurance, and
liability insurance were'included, as
indirect capital costs.
For the subset of subtitle D facilities
which could potentially become subtitle
C TSDFs in order to manage TC wastes
on-site, post-regulatory costs for on-site
management also included corrective
action costs. Corrective action costs for
units were based on data from the to-be-
proposed corrective action subpart S
rule RIA, which indicated the
probability of a »mit requiring a RCRA
facility assessment, RCRA facility
investigation, ami corrective action
cleanup. Corrective action costs were
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Federal Register / Vol. 55, No. 61 / Thursday, March 29. 1990 / Rules and Regulations
11353
not assigned to facilities which were
determined to already be subtitle C
treatment, storage, and disposal
facilities, since units at these facilities
would already be subject to corrective
action requirements under subparts S
and F, Like capital costs, corrective
action costs were converted to annual
values.
The annualized capital and (as
appropriate) corrective action costs
were added to yearly O&M costs to
derive overall annualized costs for on-
site units of various sizes. These
annualized costs were then divided by
the waste management capacities of the
units to obtain the costs per metric ton
for on-site management in different
units.
Off-site management costs were
based on commercial hazardous waste
management prices, adjusted for the
effects of above-average profits.
Shipping costs were included for wastes
sent off-site. Neither the on-site nor off-
site costs included the cost of waste
testing.
Since no data were available on the
combinations of wastestreams
generated at particular facilities, EPA
used an algorithm to create model
facilities. In estimating costs for the
model facilities, wastes that were
amenable to co-management were
grouped to identify economies of scale.
Once the costs per metric ton for
different types of on-site and off-site
management had been developed and
waste quantities for the model facilities
had been determined, EPA estimated
each facility's baseline cost based on
the quantities of waste and the cost per
metric ton for the baseline management
practices identified for the wastes. The
post-regulatory cost for each facility
was estimated in a similar way. The
post-regulatory management practices
for facilities were selected by comparing
the cost per metric ton for different
feasible post-regulatory practices for
wastes and selecting the least expensive
alternative. (This comparison was made
based on compliance costs, rather than
social costs, as discussed below). EPA
then subtracted baseline costs from
post-regulatory costs to obtain the
before-tax incremental cost for each
facility. These before-tax incremental
costs were then added across industrial
sectors to obtain the total (national)
social costs of the rule.
EPA examined the possibility that
some facilities managing wastewaters
would incur costs over and above the
cost of switching from management in
unlined surface impoundments to
management in wastewater treatment
tanks that are exempt from subtitle C.
To calculate upper bound costs, the
Agency assumed that facilities
generating large quantities of TC
wastewater (over 400,000 metric tons
per year) would not be able to convert
existing non-hazardous surface.
impoundments to tanks by the effective
date of the rule (i.e., October 1,1990)
and therefore would .become interim
status facilities under RCRA and-subject
to subtitle C closure of any
impoundments. The upper bound cost
estimates included costs for subtitle C
"landfill closure" of the surface
impoundments currently used to manage
TC waste. Costs for surface
impoundment subtitle C closure
included pumping of free liquid,
solidification of sludges, construction of
a cover system, installation of
upgradient and downgradient ground
water monitoring wells, closure
certification, and potential corrective
action costs triggered by bringing
facilities with TC surface impoundments
into the subtitle C system.
2. Compliance Costs
EPA used the same basic approach to
estimate compliance costs that was used
to estimate, social costs except that the
after-tax costs (or revenue
requirements) of management practices
were used rather than the before-tax
costs, and the price of off-site
management was used rather than the
cost of off-site management (to address
above-average profits). Since the
compliance costs reflect the cost of the
rule for particular entities within society
more accurately than the social costs do,
compliance costs were used in
determining whether it would be less
expensive for facilities to use on-site or
off-site post-regulatory management
practices.
Based on the cost analysis discussed
above, EPA estimated the number of
existing subtitle C treatment, storage,,
and disposal facilities (TSDFs) electing
to manage TC non-wastewaters on site
and the number of subtitle D facilities
which would be likely to become
subtitle C TSDFs in order to manage
their non-wastetvaters on-site. (The
focus was on on-site management of
non-wastewaters, since it was assumed
that most facilities would be able to
manage wastewaters on site without
becoming subtitle C TSDFs.) This was
done by first determining the number of
facilities that would be likely to choose
on-site management as the least-cost
management practice for non-
wastewaters and then estimating how
many of these would be likely to already
be subtitle C TSDFs. EPA also estimated
the number of new subtitle C generator?,
by determining how many facilities
would generate in excess of 100
kilograms per month of TC waste and
then calculating how many of these
facilities would be likely to already be
subtitle C generators.
c. Economic Impact Methodology. To
gauge impacts, EPA compared
compliance costs (discussed previously)
with average facility costs of production
and with cash from operations.
Financial data were obtained primarily
from the Census and Annual Survey of
Manufacturers (U.S. Department of
Commerce, Bureau of Census) and were
organized by Standard Industrial
Classification (SIC) code and facility
size. Impacts were estimated at the
facility level rather than the firm level,
due to lack of data on specific facilities
and the firms owning them.
Two ratios were used to identify
facilities likely to experience adverse
economic effects: compliance cost
divided by cost of production (the COP
ratio) and cash from operations divided
by compliance cost (the CFO ratio).
These ratios bound possible effects on
individual facilities by examining
impacts assuming complete pass- .
through.of compliance costs to
customers, on the one hand, and
assuming no pass-through of costs, on
the other. The COP ratio represents the
percentage product price increase for
facility output that would be necessary
if the entire compliance cost,
accompanied by facility profit, were to
be passed through to customers in the
form of higher prices. A change
exceeding five percent is considered an
indication of a significant adverse
' economic impact on a facility. The CFO
ratio represents the number of times that
a facility's gross margin (profif) would
cover the compliance cost if the facility
were to fully absorb the cost. For this
ratio, a value of less than 20 is
considered to represent a significant
adverse impact.
EPA then performed an analysis on
the facilities experiencing significant
economic impacts to identify the
potential for facility closures. Those
facilities for which the CFO ratio was
less than two were considered likely to
close.
Impacts on significantly affected
product markets were addressed
qualitatively by examining market
structure and the ability of facilities to
pass compliance costs on to customers.
d. Benefits Methodology. The benefits
of the final rule were evaluated by
considering the reduction in human
health risk, the reductionsin resource
damage, and future cleanup costs
avoided that would result from required
changes in management practices for
affected wastes. These benefits
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11854 Federal Register / Vol. 55, No. 61 / Thursday. March 29, 1990 / Rules., and Relations,
measures centered primarily pn the
exposure to contaminants via the
ground water medium, since this was
the route of exposure addressed by the
TC rule; however, a screening analysis
of risks via air, due to emissions from
surface impoundments, was also
conducted to gauge the significance of
these risks.
It is important to point out that the
benefits measures should not be added.
The measures provide alternative ways
of evaluating benefits of the rule, and
significant overlap between measures
does occur.
EPA estimated benefits on a
wastestream-by-wastestream basis. To
simplify the analysis of benefits, EPA
employed a screening analysis to
Identify two "risk-driving" constituents
in each wastestream, one a carcinogen
and one a non-carcinogen. These
constituents were then used in
developing benefit estimates.
A Monte Carlo modeling approach
was used to simulate fate and transport
of the constituents and subsequent
exposure to them under a variety of
waste characterizations, hydrogeologic
settings, and exposure scenarios. Based
on data from EPA's National Survey of
Solid Waste Municipal Landfill
Facilities (the "Municipal Landfill
Survey"), it was assumed that only 4fr
percent of facilities had down-gradient
wells. EPA examined the sensitivity of
results to this assumption by assuming,
alternatively, thatall facilities had
down-gradient wells.
Due to the way in which fate and.
transport of constituents was modeled
(using an infinite source, steady-state
model), benefits estimates were
primarily a function of the number of
facilities estimated to manage each
wastestream and constituent-
concentrations in the waste;
wastestream volumes did not affect*
benefits estimates. In contrast, cost
analysis results were a function of the.
number of facilities, waste- constituent.
concentrations, and wastestream
volumes.
Worst-case estimates of .baseline risk,
resource damage, and cleanup costs
Were developed by assuming that the
baseline management practi.ce for bofli
wastewatera and nan-wasjewaters was
an unlined, non-hazardous was,te ,"
landfill. This is the same assumption
that was employed by the Agency in
determining regulatory levels for TC
constituents. Post-regulatory risk,
rcaourco damage, and cleanup costs.
were estimated by assuming thatthe.,
' wastes managed as hazardous ji£der the
TC woulH be effectively prevented, fronf"
contaminating ground water a^hd would
therefore result in-no risk, resource
damage, or cleanup costs; only those
wastes continuing to be managed as
non-hazardous would pose a threat to
human health or the environment.
For wastewaters, the baseline risk,
resource damage, and cleanup cost due
to ground water contamination were
based on concentrations of constituents
in the influents to waste management
units. Consequently; since volatilization
of constituents from waste management
units was not accounted for, benefits
due to reduction in ground water
contamination may be.oyerstated.
The, thr.ee benefits measures, used.in
, this analysis are dis.cussed separately
below.
1. Human Hea,lth Risk Reduction
EPA estimated two types of human
health risk: risk to the most exposed
individual (MEI) and population risk.
Human health risk is defined herein as
the probability of injury, disease, or
death over.a given time'(70 years) due to
responses to doses of disease-causing
agents. The human health risk posed by
a Waste management practice is a'
function of the foxicity of thje chemical
constituents jn,the.wastestreanj 4$d the
extent of human'jgcpbsure.tb the
constituents. The likelihood of .exposure
is dictated by hydrogeologic and.
climatic settings at land.disposM units
arid by th'e fete apd transport of
chemical constituents in environmental
media. '-..'.
. a. MEIftiskReduction*; MEI risk was
based oil'exposure to the risk-driving
constituejats;,, Gqncentratipns of the. rjsk-
driving constituents in the waste
leachate were selected randomly from
the' constituents';concentration
distributionsi A;dilution-atteriaatidn
factor (OAF), derived from EPA's .
subsurface fate.and transport-model
(EPACML), was then randomly selected
an.d used;to model the fate and transport
of the constituents in ground water..(The
OAFs were developed using data from,
ttie Municipal Landfill Survey onjahdfill
^size, hydrpgeology, and distance from
the unit to the closest drinking water.
well; see section IH.E for further ; .
discussion of the model^By;dividing the
initial, leachateconcen,tjatiohs pf ;thev
risk-driving constituents by jtheDAF,
exposurei concentrations-at a dowrK,
gradfen^ell wereestiniatedi Ri^k'^k
from dngestibn of cd^tammatedgrQund •
water were then calculated. The
carcinogenic MEI risk was expressed as
the'probability of the MEI coriteacjirig'"
• cancer. 6veE^7^-year lifetime, dnd the
nbn-carGmqgemc MEI risk -was
expressed as an exceedance of the,
Jieaitii-effEctstficeshold,
; Risk! estSaafes.were developed WJ&te
way-for 138861016 conditions" and for the..
final rule. The difference between the
final rule and baseline risk estimate1*
yielded the MEI risk reduction (or
benefit).
EP.A conducted a separate screening
analysis of baseline MEI risks due to air
emissions from surface-impoundments
•in order to assess'whether potential air
risks were significant. This was done by
assuming that constituents in
wastewaters would potentially
volatilize to the air rather than leach to
ground water. EPA's Liner Location
Model (Ref. 32) was used to estimate
'concentrations of constituents at an ,
exposure point 200 meters from the edge
of the surface impoundment Both
carcinogenic and non-carcinogenic risks
•were estimated. .
b. Population Risk Reduction;
Population rislc Was' estimated in much
the same way as MEIrisk, with the
exception that ground water plume
areas for risk-driving constituents were
used to model the exposure of
populations located dowiigradient from
units. The plume ai:e&s were developed
for a represeiitativc hydrogeologic
environment, based on data from the
Municipal Landfill Survey;
' Each plume area contained a gradient
of exposure' concentrations, 'with the
highest concentration near the unft ,
boundary 'anjl the lowest cdhbei(tration
near the outside eelge bf the'plume. By '
assuming ai unifpritipo'pulation 'density;
of 1.6 persons per aerie, based'.pn'.'the . '
Municipal Landfiiil Suryeyi it was '••
possible i to estimate the number 'of.
piersons'expQSedfeeachof'the '
concentra,tio;n^els. within each plume.
.. . .
carcinogenic' cohslituent.^^^ on; the
constituent's,,risk-Hpecific dbse.(RSD),
was expressed as the;number bif cancer
cases over a yd-ye^r lifetime. The
population risk.foi' the non-carcuiogenie
constituent, based on the, coristituent's ,
Teference dose (RfD), "was expressed as
the ro^beir of .perijbhs e?q)osed to, . ; | •
aveiage daily C94i-entrations 'eXeeediJig
tiie Rff) Wer a 7p-year peribtlr
2. Resource Damage Avoided
,Kespurce tjamage measures^the cbsi
, assbbiSted wiUi"reipl£icing cdr^taminated.
grojind, water vthat had ^een used as' a,
source of drjin^ing water. ;Resoijrce..
damage.vtfas assumed to, resuli frpnJiany
contaniin3,tiqn of grbund water Wjiieh •'
vypuld render ^unsuitable for- human.:
cbnsvjmptiftni.dtheir potential foipegone
uses, such as
Ifthe iconcenftatioti..of ,f£9138.
ground water.excjijeded ja^niax'liinun^:
;conta^irianflevel (J4CL);.the. ground
water was assumi3d.tp.be damaged. If
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Federal Register / Vol. 55, No. 61 / Thursday. March 29, 1930 / Rules and Regulations
22057
the contaminant did not have an MCL
but the concentration exceeded a taste
and odor threshold or a health effects
threshold, the ground water was also
assumed to be damaged. Areas^of
damaged ground water were derived
based on-a comparison of the
constituent's concentration within the
plume with the constituent's MCL, taste
and odor threshold, or health-based
number, in an approach similar to that
used to estimate plume areas for
population risk.
" To place a value on the damaged
resource, EPA assumed that.an
alternative water supply system would
have to be built to provide water to
persons living above the area of the
damaged ground water. The costs of
constructing the water supply system
included capital and O&M costs; these
costs were discounted to the present at
a rate of three percent to obtain the-
resource damage per facility. Addition
of resource damage across facilities •
provided a national estimate.
3. Cleanup. Costs Avoided
As an alternative measure of benefits,
EPA estimated the cleanup costs
avoided as a result of the TC rule. Costs
of cleanup of contaminated ground
water were estimated by assuming that
sites with resource damage in the
baseline would eventually require
cleanups. To develop an upper bound
estimate, it was assumed that sites with
resource damage greater than $1,000,000
(present value) would require cleanup.
Cleanup costs were based on an
average cost of $15 million per site, with
cleanups beginning in 15 years. EPA
estimated the average cost of cleanup
by examining recent Superfundrecords
of decision (RODs) for sites
contaminated with TC constituents that
required substantial ground water
cleanup efforts. Costs were discounted
to present values using a discount rate
of three percent
e. Used Oil Methodology. EPA
addressed the impacts of the TC on used
oil separately from other wastes for
several reasons. First, used oil is
generated across a wide variety of
industrial sectors. Second, unlike other
wastes, it has economic value and can
be sold in intermediate or end-use
markets; this complicates any analysis
of the costs of regulating it as a
hazardous waste. Also, data on used oil
are quite limited. Finally, it is difficult to
accurately estimate quantities of used
oil that may exhibit the TC because hi
practice TCLP filtration is sample-
specific and difficult to predict
The analysis of costs, economic
impacts, and benefits associated with
used oi) was qualitative in nature; no
attempt was made to develop national
estimates. In determining the quantity of
used oil potentially affected, EPA
excluded used oil that was: (1) Already
hazardous because it exhibits a
hazardous waste characteristic (e.g.,
ignitability); (2) recycled; or (3)
generated by "do-it-yourselfers" (i.e.,
auto owners disposing of crankcase oil).
In order to develop' worstcase estimates
of impacts on used oil, it was assumed
thatusedoilwouldfilterintheTCLP.lt
was also assumed that the facilities
managing used oil were subtitle D
facilities. Finally, estimated-impacts on
used oil did not account for the possible
stigma associated with management of
used oil as a hazardous waste.
4. Results
Results of the RIA are presented
below. These results are approximations
that are intended to identify the most
significant impacts of the TC rule. As
discussed previously, there were no
data on the waste types and quantities
generated by specific facilities hi the
different industrial sectors. Therefore,
EPA used more aggregated data and
focused on those industrial sectors
which were most likely to generate
significant quantities of TC wastes.
a. Affected Wastes and Facilities.
EPA estimated the amount of waste and
the number of facilities that would be
"affected" by the rule, i.e., feat would'
incur any incremental costs due to
required changes in management
practices for newly hazardous wastes.
1. Affected Wastes
The overall quantity of waste affected
by the TC was driven by wastewaters,
EPA estimated the quantity of affected
wastewaters to be approximately 730
million metric tons (MMT) per year and
the quantity of affected non-
wastewaters (sludges and solids) would
range from approximately 0.85 MMT/
year to 1.8 MMT/year. It should be
noted that the affected wastewaters,
which would be hazardous wastes, are
assumed to be exempt from subtitle C
regulation in the post-regulatory
scenario due to their management in
exempt tanks. However, they would be-
affected wastes because a change in
management practice (from surface
impoundments to tanks) would be
required.
The industrial sectors with the largest
quantities of affected wastewaters were
Petroleum Refining (SIC 2911), Organic
Chemicals (SIC 286), Synthetic Rubber
(SIC 2822), and Cellulosic and Non-
Cellulosic Synthetic Fibers (SICs 2823
and 2824). For the lower bound estimate
of 0.85 MMT/year of non-wastewaters
affected, the sectors with the largest
quantities of affected non-wastewaters
were Pulp and Paper (SIC 26), Synthetic
Fibers; Organic Chemicals, and
Pharmaceuticals (SIC 283). For the upper
bound estimate of 1.8 MMT/year,
industry sectors generating the •largest
quantities of affected rion-wastewaters
were Pen-oleum Refining, Pulp and
Paper, Synthetic Fibers, Organic
Chemicals, and Wholesale Petroleum
Marketing (SIC 517). Certain sectors
generate significant quantities of both
wastewaters and non-wastewaters due
to the wastewater treatment sludges
associated with wastewater streams.
. Most of the affected wastewaters and
non-wastewaters are believed to be
generated by large facilities.
A total of twelve constituents
appeared as "cost-driving" constituents
in the analysis. However, benzene was
the driving constituent for over 60
percent of the affected waste quantity.
Other volume-driving constituents
include chloroform (25%), vinyl chloride
(17%), and trichloroethylene (15%).
2. Affected Facilities
EPA estimated that between 15,000
and 17,000 generators would be affected
by the rule. Costs and additional
requirements among these affected
facilities will vary (e.g., some may
already be RCRA generators or TSDFs,
others may need to apply for RCRA
permits or send wastes off-site). Over 90
percent of these were small facilities
(with fewer than 50 employees). The
industries with the most affected large
facilities were Hosiery and Knit Fabric
Finishing (SIC 225), Wholesale
Petroleum Marketing, Organic
Chemicals, Petroleum Refining, and
Plastics Materials and Resins (SIC 2821).
The industries with the most affected
small facilities were Wholesale
Petroleum Marketing, Hosiery and Knit
Fabric Finishing, Miscellaneous
Petroleum and Coal Products (SIC 2992),
Organic Chemicals, and Plastics
Materials and Resins.
3. Sensitivity Analysis of Affected
Wastes and Facilities
Changes in certain analytical
assumptions had significant effects on
the quantity of waste and number of
facilities affected by the TC final rule.
(Refer to section VI.B.3.a for discussion
of the sensitivity analyses which were
conducted.) Some of the changes also
affected cost and benefit results, as
discussed below under cost results and
benefit results.
Assuming that oily wastes would not
filter in the TCLP, rather than assuming
that they would, would have a very
significant effect on the quantity of non-
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1195ft « >F|3de*al Register?
Thursday. March^o;
wastewaters affected by the TC. This,
effect can be seep In the difference
between lower bound (assuming oily
wastes do not filter) and upper bound
(assuming oily wastes filter without
complications) estimates of affected
quantities of non-wastewaters. Nearly •
all of the non-wastewaters from
Petroleum Refining (including a very •
large-volume primary treatment sludge),
Wholesale Petroleum Marketing, and •
Petroleum Pipelines are oily wastes.'
Assuming that all wastewaters were
managed in surface impoundments,
rather than some portion being managed
by practices exempt under subtitle.C,
Increased affected wastewaler quantity
significantly to approximately 1,900
MMT/year. It also increased the number
of facilities affected in certain sectors.
Finally, assuming that only 10 percent
of the facilities would be affected for a
waste failing the TC, rather than using
the percent of the waste failing,
significantly reduced the number of
facilities affected by the TC in most
industrial sectors.
b. Cost Results—1. Social Costs and
Compliance Costs. EPA estimated the
total social costs of the TC rule
(excluding taxes and above-average.
profits) to be approximately $90 million
to $310 million per year (present value
$1.3 billion to $5.7 billion); this does not
include costs associated with used oil.
Compliance costs (which include taxes
and above-average profits) ranged from
$130 million to $400 million per year
(present value $1.9 billion to $5.0 *
billion). While affected Waste quantities
were driven by wastewaters,'
compliance costs (for the scenario
where oily wastes fall the TC and no
surface impoundment closure; cosis.are
Incurred) were driven by non:
wastewaters due to the significantly
higher incremental costs of managing
non-wastewaters. Non-wastewaters
accounted for over 95 percent of
compliance costs.
For the lower bound cost estimate, the
Industrial sectors with the largest
compliance costs were Pulp and Paper,
Synthetic Fibers, Organic Chemicals,
and Synthetic Rubber. For the upper
bound cost estimate, the industrial
sectors witlv the largest compliance.
costs were Petroleum Refining.JPulp and
Paper, Synthetic Fibers, Wholesale
Petroleum Marketing, and Organic
Chemicals, Constituents driving the cost
results were: benzene, chloroform;
trichloroethylene, vinyl chloride, and
carbon tetrachloride.
Approximately 90 percent of the
compliance costs, (for the scenario
where oily wastes fail the TC and no
surface impoundment closure costs are
incurred) were incurred by large.
facilities and 10 percent by small:
facilities across industrial sectors. .A
relatively small number of large
facilities incurs the majority of
compliance costs because large facilities
are believed to have much.greater waste
generation rates than small facilities. •
The estimated number of subtitle D
facilities seeking permits, to-become non-
commercial subtitle G TSDFs was 40 to
250; this does not include facilities
seeking permits for storage or treatment
only. Most of the expected permit
applicants were in the Pulp and Paper
Industry in the lower bound estimate.'
Most of these new TSDFs in the upper-
bound estimate were in Petroleum
Refining.
The number of existing subtitle C non-
commercial TSDFs expected to seek
permit modifications to handle TC
wastes-was between 45 and 220,
depending on whether permits are
considered for only disposal or for
treatment, storage, and disposal. Most of •
these facilities in the upper bound
estimate were in the Wholesale
Petroleum Marketing and Petroleum
Refining industries.
The number of subtitle C commercial
TSDFs (SIC 4953) seeking permit
modifications OT changes to interim
status could be as high as 360, the
estimated number of existing
commercial TSDFs. Many of these
commercial TSDFs are'primarily storage
facilities.
In addition, the TC rule would result
in' as many'as 15,000new subtitle C
generators; Most of the new generators
would be in Wholesale Tetroleum
Marketing and Hosiery and Knit Fabric
Finishing.
2. Sensitivity Analysis of Costs.
Changes in certain analytical
assumptions had- significant ;effects on
the social costs and"compliance Costs of
the TC final rule. (Refer to section
VLB.3.a for discussion of the sensitivity
analyses which were conducted.) Some
of the changes also affected benefit'
results, as discussed below under
benefits results.
Assuming that oily wastes would not
filter in the TCLP, rather than assuming
that-they would, would have a
significant effect on both social costs
and compliance costs. The Agency.
estimated, as a lower bound assuming
that no oily wastes will fail theTC test,
social costs of about $90 million per year
and compliance costs of about $130
million'per year. By comparison, if it
were assumed for the purpose of
predicting TCtP results thatoily wastes
behave like other nonrliquid wastes,
social costs would be $190 million per
year and compliance costs would be
$250 million per year.
Assuming that not all facilities would
be able to convert Within six months <
from surface impoundments to tanks for
management of their TC wastewaters,
. rather than assuming that all facilities
would be able to convert, significantly
increased the cost of the rule. Based on
landfill closure of impoundments, this
assumption added approximately $120
million to annual social costs'and $140
million to annual compliance costs.
Splitting wastestream quantity evenly
between small and large facility size .
categories, rather than based on value of
shipments, shifted wastes from large to
small facilities. While this did not affect
the overall costs greatly, it significantly
decreased compliance costs for large
facilities' and increased them for small
fs cilitifi s
Finally, assuming that only 10 percent
of the facilities would be affected for a
waste failing the TC, rather than using
the percent of the waste failing,
significantly reduced social costs and
compliance costs due to the larger
quantities of wastes being managed at a
smaller number of facilities and the
resultant economies of scale. The
estimated number of new subtitle C
TSDFs, existing TEiDFs seeking permit
modifications, and new subtitle C
generators also decreased significantly.
c.'Economic Impact Results—1.
Significantly Affected Facilities. Based
on the economic impact criteria
discussed previously the estimated total
number of significantly affected
facilities was 65 to 81, of which most (51
to 66) are large. The fact that most of the
significantly affected facilities are large
can be partially explained by the fact
that data indicate there are no small
facilities'in certain sectors (e.g.,
Cellulosic Synthetic Fibers). Another
reason for the preponderance of
Significantly affected large facilities is
that for some wastes, total compliance
costs are less for fimall facilities than for
large facilities because large facilities
are believed to generate significantly
more waste..
In the lower bound estimates,
significantly affected facilities were.
expected in four industrial sectors: Pulp
and Paper, Synthetic Rubber, Synthetic
'Fibers, and Organic Chemicals. In the
lower bound estimates the Pulp and
Paper industry was predicted to have
the greatest number of significantly
affected facilities (35), of which 30 are
large facilities. The synthetic rubber
industry had the highest number of
significantly affected small facilities (8),
out of a total of 14 significantly affected
small facilities. None of the industries
examined were expected to suffer
facility closures as a result of the TC.
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Federal Register / Vol. 55, No, 61 /Thursday, March 29, 1990 / Rules and Regulations 11857
In the upper bound estimates,
significantly affected facilities were
expected in seven industries: Pulp and
Paper, Synthetic Rubber, Synthetic
Fibers, Organic Chemicals, Textiles,
Pharmaceuticals, and Plastics and
Resins. Pulp and paper had the largest
number of significantly affected
facilities—36 out of 80 for all facilities.
2. Effects on Product and Capital
Markets
The industries with significantly
affected facilities have very little
potential to pass compliance, costs oh to
consumers in the form of higher prices.
These industries produce primarily
intermediate goods (e.gr; rubber, paper,
fibers, and chemicals] which are used in
a number of subsequent prpcesses (e.g.,
manufacturing and fabrication) before -
they reach consumer markets. The users
of these intermediate products have
access to similar or identical products
from U.S. suppliers that are not
significantly affected by the TC and
from foreign suppliers; biecause^
substitutes are available, these users
would not be forced to pay higher .prices
for the intermediate products.
While results suggest that prices in
product markets will not be affected, at
least some impact.is likely on capital
markets. Because affected, facilities will
not be able to pass compliance'costs
through to buyers in the form of higher
prices, they .will experience lower
profits. Lower profits will reduce, the
value of capital tied up in thest*
facilities. However, as most of the
affected facilities are part of integrated
production systems and are o.wned by
large firms with significant asset'
holdings, the effect on capital markets
(i.e., stock prices and bond ratings)
should be relatively small.
3. Sensitivity Analysis of Economic
Impacts.
A change in one of the analytical
assumptions had significant effects ori
'economic impacts due to the TC final
rule. Refer to section VI.B.3,a fbi;
discussion of the sensitivity analyses
which were conducted.
Splitting wastestream quantity evenly
between small and large facility sizes
categories, rather than based on value of
shipments, shifted wastes from large to
small facilities. Under the scenario
where oily wastes fail the TC and no
surface impoundment closure costs are
incurred, this resulted in nearly 40
additional small facilities with
significant economic impacts and 10
small facility closures;
d. Benefits Results. EPA,estimated tfte
benefits of regulating TC wastes on a
wastestream by wastestrbam basis;:
results of this analysis,are presented.in.
Table VI-3. As discussed in the benefits
rnethodology section, results for
different benefit measures {human
health risk, resource damage, and
cleanup costs avoided) are likely to
overlap and should not be added.
TABLE VI-3.—BENEFITS OF THE TC RULE
Reduction in MEI Risk:
•Reduction, in .Carcinogenic .370.to.780i
Risk (number of facilities with ' " '
risk greater than 1X10E-5 at
down-gradient well).
• Reduction in Non-Carcinogenic 8.
, Risk (number of facilities with '
exposure above a health-based
. -threshold at downgradient well).
Reduction In Population Risk:
• Reduction in '• Carcinogenic 6.
Risk (number of cancer cases
•over 76 years).
'•Reduction in: Non-Carcinogenic 320.
Risk-(number of persons with
exposure above a health-based
threshold - at downgradient
wells). ; . , .
Reduction in Resource Damage 3,800.
(present value, millions of 1988
dollars). . .
Cleanup Costs Avoided (present Up to 15,000.
value, millions of 1988 dollars).
1. MEI Risk
As can be seen from the table, there is
a potentially significant reduction-under
the final rule in the carcinogenic risk to
the most exposed individual (MEI)..
There.are from 370-78Q fewer facilities
managing wastes that present risks to
the most exposed individual (MEI)
greater than ixiOE-5 under the final
rule than'there were under baseline
conditions. The industrial sectors
driving these benefits, include Wholesale
Petroleum Marketing (SIC 517) and
Miscellaneous Plastics Products (SIC
3079). The constituent driving most of
these benefits is benzene. The difference
between the lower and upper bounds
results from certain oily wastes that are
unregulated in the lower bound.
For non-carcinogenic MEI risk, there
are 8 fewer facilities managing
wastewaters where the exposure to.'a
npn-carcinogenic constituent exceeds
the reference dose (RfD) under the final
rule than,under baseline conditions.
-Wastes fjoni Wholesale Petroleum
Marketing drive these benefits results.
Cresols are the risk-driving constituents.
The Wholesale Petroleum Marketing
sector presents significant risks due to
the large Jnumber of facilities managing
wastewaters and non-wastewaters. .The
number of facilities in this sector
estimated to manage wastewaters and
non-wastewaters are 1,290 and 1,050
facilities, respectively; this compares
with 1,900 and 8,600 facilities,;,
respectively, managing affected
wastewaters .and non-wastewaters
across .all industrial sectors.
A screening analysis of MEI risks due
to air,emissions from surface
impoundments was conducted to gauge
the potential risk via the air medium.
This analysis indicated that in sectors
other than Wholesale Petroleum
Marketing approximately 20 percent of
modeled facilities had carcinogenic risks
, greater than I.XIOE"5 and 5 percent had
non-carcinogenic doses greater than the
RfD; MEI air risks from Wholesale
Petroleum Marketing were less than
1X10E~S. Benzene contributed most of
the carcinogenic risks while phenol was
responsible for most of the non-
carcihogeijie risks.
The industries generating wastes with
; high MEI air risks differ to some extent
from those generating wastes with high
MEI ground water risks. The industries
generating wastes with high MEI air
risks include Pulp and Paper, Plastics
Materials and Resins, Synthetic Rubber,
Cellulosic and Non-Cellulosic Synthetic
Fibers (SICs 2823 and 2824), and Organic
Chemicals.
There is.some potential overlap'in
estimates of air and ground water risk.
The wastewater MEI risks via ground
water were based on the assumption
' that; all 'the constituent mass was •
•available for leaching to ground water;
in 'contrast, the air risks assumed some
percentage of constituent mass would
volatilize from impoundments. As a
result, the wastewater MEI risks via
ground water ark likely to be overstated.
2. Population Risk
Based on a very limited analysis of
population risk, EPA estimates that
there would be six fewer cancer cases
over the 70-year modeling period due to
the final rule. Wholesale Petroleum
Marketing (constituent: benzene) and
Plastics and Resins (SIC 2821)
(constituent: vinyl chloride) drive these
benefits. The reduction in number of
persons exposed to non-carcinogens at
concentrations greater than the RfDs
was estimated to be 320 over a 70-ye.ar
period. Sawmills and Planing Mills (SIC
2421) and Organic Chemicals
.{pehtechlorophenol.and methyl ethyl
xeytone) drive these results.
3. Resource Damage
,The total reduction in resource
damage would be approximately $3.8
billion (present value). Wholesale
Petroleum Marketing and Miscellaneous
Plastics Products are the industrial
sectors driving resource damage
benefits, Benzene is the driving
constituent.
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11858 Federal Register / Vol. 55, No. 61 / Thursday, March 29, 1990 / Rules and Regulations
4. Cleanup Costs Avoided
Estimated cleanup costs avoided due
to the final rule ranged up to $15 billion
(present value). Under the assumption
that all sites with significant resource
damage (i.e., resource damage greater
lhan $1,000,000 (present value)) would
require cleanup, approximately 1,600.
facilities would require cleanup.
5. Sensitivity Analysis of Benefits
Changes in certain analytical
assumptions had significant effects on
the benefits of the TC final rule. (Refer
to sections VI.B.3. a and d for discussion
of the sensitivity analyses which were
conducted.) Some of the changes also
affected cost results, as discussed under
cost results.
Assuming that oily wastes would not
filter in the TCLP. rather than assuming
that they would, would reduce the
benefits associated with non-
wastowaters, as can be seen in the
lower bound estimates indicated in the
results above. This would result
primarily from the significant reduction
in the number of facilities managing
non-wastcwaters in Wholesale
Petroleum Marketing.
Assuming that all wastewaters were
managed in surface impoundments,
rather than some portion being managed
by practices exempt under subtitle C,
would increase the number of facilities
affected in many sectors and increase
benefits significantly. Benefits for.
wastewaters could increase by
approximately 10 times since there
would be 10 times as many facilities
with surface impoundments.
Assuming that only 10 percent of the
facilities would be affected for a waste
failing the TC, rather than using the
percent of the waste failing, significantly
reduced the number of facilities affected
by the TC in all industrial sectors". This
would significantly reduce benefits as a
result, since fewer facilities would be
managing wastes.
Assuming .that all facilities have
down-gradient wells, rather, than
assuming only 48% have down-gradient
wells, would increase benefit results by
a factor of approximately two.
o. Cost-Effectiveness. The Agency
estimated the cost-effectiveness of the
final rule and of several regulatory
alternatives. This discussion is
presented in the regulatory impact
analysis document, which is part of the
public docket for the rule.
/ Used OH Results. Used oil is
generated across a wide variety of
industrial sectors. Some generators
manage or dispose of their used oil
directly while others provide their used
oil to the^used oil management system
(UOMS), a system of intermediate
collectors and processors (Ref. 33).
Firms in the UOMS then re-refine or
process the used oil and/or sell it for
various end uses.
Under the worst-case assumption that
used oil would not create TCLP filtration
problems, EPA found based on
constituent concentration data (see Ref.
8). that virtually all used oil would fail
the TC. EPA determined that three end-
use management practices for used oil
would be affected: landfilling/ .
incineration, dumping, and road oiling.
Once used oil became TC hazardous,
it would have to be shifted to other end-
use management practices. Much of the
used oil that is currently dumped .or
applied directly to roads by generators
would probably be collected and sold to
the UOMS. Firms in the UOMS that
currently sell used oil for road oiling
would generally shift this oil to other
management practices, such as re-
refining or burning as a fuel. Used oil
that is managed by landfilling or
incineration in subtitle D units would
likely be shifted to management in
subtitle C units.
The shift in management practices
would impose costs on used oil
generators, the UOMS, and end-users of
used oil. Used oil generators currently
providing used oil to the UOMS would
be likely to pay somewhat higher
collection costs due to pass-through of
compliance costs by firms in the UOMS.
Generators that currently manage their
wastes by road oiling would incur
storage and collection costs for their
used oil as well as costs for a road-oiling
substitute. Generators directly managing
their wastes by dumping would incur
costs for storage and collection. Firms in
the UOMS that sell used oil for road
oiling would be forced to sell the oil in
less profitable markets, and some firms
could close if unable to enter another
market Firms in the UQMS could'also
incur costs for disposal of low quality
used oil and related wastes in.subtitle C
(rather than subtitle D) units if these
wastes were TC hazardous; as
discussed above, some of these costs
could be passed on to used oil
generators. Firms 'that re-refine used oil
could benefit from the TC rule, since a
greater volume of used oil would
potentially be ayailable-at a lower price.
Finally^ end-users that purchase used oil
for road oiling would incur costs for an
alternative dust suppressant
The shift in management practices
could also result in certain benefits. A
previous study of-carcinogenic risks •
from used oil management practices
(Ref. 34) indicates that dumping of used
oil may present significant risks.relative
. to other management practices (with the
possible exception of burning in boilers,
where risks are more comparable). Road
oiling appears to present more
significant risks than recycling and
comparable or fewer risks relative to
burning in boilers or landfill disposal. It
is difficult to draw definitive
conclusions concerning benefits due to
the different constituent profiles and
population densities associated with
each of the management practices in the,
risk analysis.
C. Regulatory Flexibility Analysis
1. Approach
The Regulatory Flexibility Act (5
U.S.C. 601 et aeq.) requires that
whenever an agency publishes a notice-
of rulemaking, it must prepare a
Regulatory Flexibility Analysis (RFA)
that describes the effect of the rule on
small entities (i.e., small businesses,
small organizations, and small
governmental Jurisdictions). An RFA is
unnecessary, however, if the Agency's
administrator certifies that the rule will
not have a significant economic effect
on a substantial number of small
entities.
EPA examined the final rule's
potential effects on small entities as
required by the Regulatory Flexibility
Act, Three measures, based on EPA
guidelines for conducting an RFA, were
used to determine whether the rule
would have a ^'significant economic
effect" on small entities: the.ratio of
compliance cost to cost of production, ,
the ratio of compliance cost to value of
sales, and the ratio of cash from .
operations to compliance cost (the last
ratio being used to assess potential
closures). Two of the three criteria, the
ratio of compliance cost to cost of
production and the ratio of cash from
. operations to compliance cost, are
discussed in section VI.B.3.C. The third,
the ratio of compliance cost to value of
sales, was estimated for small and large
facilities; if the difference between these
ratios was. greater (than ten percent, this
indicated a significant impact.
The guidelines for conducting RFAs
are somewhat ambiguous with respect
to evaluating impacts based on the third
criterion. Determining whether the
difference between: ratios exceeds ten
percent can be done by subtracting the
large facility ratio from the small facility
ratio or by dividing[ the small facility
ratio by the large facility ratio. Dividing
the small facility ratio by the large
facility ratio may incorrectly indicate
siqnificaht impacts on small facilities
when both ratios are very small but the
small facility ratio is larger than the
large facility ratio. (For example, a small
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Federal Register / Vpl. 55. No. 61 / Thursday, March 29. 1990 / Rules and Regulations 11859
facility ratio of 0.00002 divided by a
large facility ratio of 0.00001 would '
indicate a significant impact on small
businesses based on the division
approach, despite the-fact that the very
low ratio-of compliance cost to value of
sales for small facilities indicates little
impact on small facilities.) Therefore,
the division approach must be
interpreted with caution.
A "substantial number" of small
entities was assumed to be 20 percent or
more of the population of small
businesses, small organizations, or small
government jurisdictions within the
universe of facilities affected by the
rule.
The Agency defined a small business
as a business employing 50 employees
or less. (Standard Small Business
Administration criterion is 500
employees.) EPA decided to use the 50
employee definition of a small business
because the RIA estimates facility-level
impacts, and the SBA definition applies
to entire firms. The SBA definition
would designate most of the facilities in
the examined industries as small
businesses, Which would obscure
differential impacts on smaller facilities.
Impacts' on small businesses related to
costs of compliance for used oil and
contaminated soils were not examined
due to lack of data on the facilities
experiencing those costs.
2. Results
The only entities found to be affected
by the final rule were small businesses,
defined here as businesses employing
fewer than 50 persons.-No small
. organizations or small government
jurisdictions were identified as potential'
TG waste generators in the TC industry
studies which form the foundation for
this analysis.
The Agency did not identify any
industries in which 20 percent or more
of the small businesses were
significantly affected based on the ratio
of compliance 'cost to cost of production,
the. ratio of cash from operations to
compliance cost, or the ratio of
compliance cost to value of sales [using
the subtraction approach). Using the
division approach for the ratio, of
compliance cost to value of sales
indicated that small businesses in four
sectors (including Pulp and Paper,
Synthetic Rubber, Organic Chemicals,
and Wholesale Petroleum Marketing)
would be significantly affected.
However, since the small facility and
large facility ratios were both quite
small (small facility ratios were less
than 0.03), the Agency does not expect
significant small business impacts in
these sectors. Based on these results,
EPA Has concluded that today's final
rule will not have a significant effect on
a substantial number of small entities.
As a result of this finding, EPA has not
prepared a formal RFA in support of the
rule. More detailed information on small
business impacts is available in the RIA
for this rule.
D. Response to Comments on RIA for
fane 13,1986 Proposal
EPA. received many, comments on the
RIA for the proposed TG rule. This
section presents* a general summary and
analysis of the public comments
concerning the original RIA; all of the
comments are addressed in the
background document for this final rule.
Major issues addressed by commenters
included consideration of particular
industries, specific aspects of cost and
benefit methodologies, cost and benefit
estimates, and the assessment of small
business impacts.
1. Industries Included in the Analysis
The majority of comments on the RIA
for the proposed rule concerned the
absence of specific industrial sectors
from the group examined for potential
impacts. Other commenters criticized
the RIA for not considering the effects of
the TC on end users of products and on
facilities such as Publicly Owned
Treatment Works and Municipal
Landfills.
Industries that commenters suggested
should have been evaluated included
natural gas production, manufacturing of
a variety of products, including forest
products, Pharmaceuticals, automobiles,
plastics, metals, polyvinyl chloride,
semi-conductors, wire and cables, and
waste management. The Agency agrees
with commenters that a number of
industrial sectors were not addressed in
the RIA for the proposed rule. The
Agency notes, however, that several of
the wastestreams that commenters
believed should have been included in
the RIA (based upon the proposed
regulatory levels) are not expected to be
defined as hazardous based up'on the
final regulatory levels being
promulgated today. One of the
fundamental problems with determining
which industries would potentially be
affected by the TC is lack of data on
currently non-hazardous .wastes. Since
these wastes are currently outside the
subtitle C system, requirements for
information gathering related to them
are minimal.
The Agency made extensive efforts, in
preparing the RIA for the TC final rule,
to obtain data on the industrial sectors
potentially affected by the TC. These
data were derived from a variety of
sources. The Agency contacted
numerous trade associations and
individual facilities and collected
pertinent EPA and other government
publications. In addition, EPA prepared
a series of TC industry study reports on
those sectors most likely to generate
significant quantities of TC wastes.
In preparing its TC industry studies,
EPA first conducted preliminary studies
which examined a large number of
industries, with emphasis on identifying
whether or not TC constituents would
be likely to be present in industry
wastes. Based on the preliminary
studies, EPA completed-detailed profiles
of potentially affected industries for use
in the final RIA. The Agency examined
the potential for impacts on a number of
industries that were not considered in
the RIA for the proposed rule, as well as
reconsidering some that were addressed
in that RIA. Table VI-1 in section VLB
compares the coverage of industries for
both the proposed rule RIA and the final
rule RIA and indicates.the industries for
which detailed quantitative analysis
was conducted.
Commenters also criticized the
proposed rule RIA for not considering
effects on end-users of products
containing TC constituents. Examples of
such end-user industries include
agricultural chemical users, transporters,
automotive maintenance facilities,
petroleum retailers, medical facilities,
and research laboratories. The Agency
recognizes that TC toxicants exist in a
variety of substances, and that end-
users as well as producers of products
containing TC constituents could be
affected by the rule. Some end-users not
identified in the RIA may be affected,
but there is no information to quantify
these potential impacts. The Agency
believes that some of the impacts on
affected end users may be mitigated by
small quantity generator regulations
under 40 CFR 261.5.
Finally, several commenters
questioned EPA's assessment of impacts
on Publicly Owned Treatment Works
(POTWs), resource recovery facilities,
public water suppliers, municipal
landfills, the electrical services industry,
and currently regulated RCRA facilities.
As discussed previously in section
III.K.2, the Agency has tested a number
of POTW sludges to determine whether
or not these sludges would be
considered hazardous under the TC; the
data generally indicate that these
wastes would not be affected by the TC
(Ref. 8). Because the final regulatory
level for chloroform is significantly
higher than originally proposed, EPA
believes that public water suppliers also
are unlikely to generate TC wastes. The
Agency analyzed wastestreams
generated by the Electrical Services
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Federal Register 7 Vol. 55. No. 61 /Thursday, March29.1990 /_ Rules and Regulation^
industry. These wastes were, excluded
from the RIA because they are fossil fuel
combustion wastes, which are exempt
from subtitle C regulation until a
determination is made as to whether
they should be regulated as hazardous.
The Agency acknowledges that some
waste generated by waste management
facilities may exhibit the TC; however.
most of these, wastestreams that
commenters believed should be included
are not expected to exhibit the TC under
the final regulatory levels. Finally, ',
impacts on currently regulated RCRA
facilities [in the industries included in
the RIA) were addressed in the RIA.
2. Estimation of Costs and Economic
Impacts
Many commenters expressed concern
that the compliance cost estimates for
facilities included in the economic
impact analysis did not capture many of
the expenditures faced by handlers of
hazardous waste.' The most common
criticism was directed at the omission of
the cost for actually performing the
TCLP. Oilier commenters mentioned
insurance costs and costs associated
with RCRA permit applications. Another
large group of comments concerned the
costs for permitting and retrofitting the
large universe of surface impoundments
containing wastewaters which would
exhibit the TC. In addition, a number of
commenters contended that the RIA
significantly underestimated potential
economic impacts of the TC.
Other commenters claimed that the
expense of the highly sophisticated
equipment and specially trained
personnel necessary for the testing of
wastes would pose a significant burden
on many firms, especially those without
on-site laboratory facilities. The Agency
recognizes that testing of wastes could
pose a significant expense for firms that
choose to test their wastes. On the other
hand, there is currently no RCRA
requirement for generators to test their
wastes; the determination of
hazardousness may be made based on
cither laboratory analysis of the waste
or on knowledge of the waste, raw
materials, and production processes.
The Agency expects that many
generators will rely on the latter
method, and elect not to perform the
TCLP. The Agency is still considering
promulgating a testing requirement at a
future date. If a testing requirement is
proposed, potential costs of testing will
be analyzed hi detail.
Recognizing that administrative and
insurance costs can constitute a
significant portion of waste management
costs, the Agency considered these in
cost estimates in the final RIA. In
addition, the "ost of preparing RCRA
permit applications is considered in the
cost of subtitle'C waste management, as
are items such as liability insurance,
personnel training, and contingency
planning.
In response to comments that surface .
impoundment impacts were understated,
the Agency examined the effect of the
TC rule on wastewaters and estimated
the costs of compliance with subtitle C
requirements. The Agency assumed in
the final RIA that, based on least-cost
management practices, surface
impoundments would not have to be
retrofitted. Instead, it was assumed that
affected wastewaters would be
segregated and treated in a separate
tank system, while remaining non-
hazardous wastewaters could continue
to be managed HI the impoundments. In
deriving an upper bound estimate of
costs, it was assumed that some
impoundments would have to undergo
subtitle C clean closure.
Given the broad scope of the TC rule
and the general lack of data on
industries and facilities managing
currently non-hazardous wastes, the
Agency agrees that economic impacts
on certain sectors may have been
underestimated in the RIA for the
proposed rule. As discussed above, the
Agency has made significant efforts in
the final RIA to more accurately
characterize the sectors potentially.
affected by the TC arid to estimate the
actual impacts on affected facilities.
3. Estimation of Benefits
Several commenters remarked on the
original methodology used for the
estimation of benefits. The most
frequent target of criticism was the
assumption that all contaminated
aquifers would be cleaned up as a result
of the TC. Commenters also questioned
the validity of assuming that ground'
water resource conditions in North
Carolina were representative of
conditions across the entire United
States.
Commenters on the use of aquifer
cleanup as the basis for estimating
benefits of the proposed rule asked for
justification of the assumption that all
aquifers would be cleaned up and an.
explanation of the benefits to human
health and the environment which
would result from the cleanup. The
Agency used a different methodology to
estimate benefits for the final RIA than
was used for the original RIA. For the
final RIA, EPA examined three potential
types of benefits: human health risk
reduction, resource damage .avoided,
and cleanup costs avoided. The
assumption that all aquifers wjould be
cleaned up was not used in the final
RIA. In estimating benefits based on
cleanup costs avoided through
controlled subtitle C management of TC
wastes, EPA assumed in the RIA for the
final rule that, for the near term, the
subtitle D facilities with-down-gradient
wells and with at least some resource
damage (as predicted by the resource
damage analysis) would be the most
likely candidates for cleanup.
The Agency agrees with the comments
that ground water resource conditions in
North Carolina may not be
representative.of conditions across the
entire United States. As a result, in the
final RIA EPA used distributions of
hydrogeolqgic'parameters which were
representative of nationwide conditions,
rather than relying on hydrogeologic
information from one state.
4. Cost-Benefit Comparisons
In general, comnnenters argued that
the RIA overestimated likely benefits of
the proposed rule while underestimating
the potential impacts, Commenters
believed (that the TC would bring large
quantities of waste into the subtitle C
system, with little oir no attendant
environmental or health benefit. One
commenter claimed that, after all
•indirect impacts are considered, the.net
benefits of the rule could be negative.
Another commenter, however, stated
that benefits were actually
underestimated because of assumptions
in the baseline scenario.
The Agency has used an improved
methodology and additional data in the
final RIA. EPA believes that the final
RIA: provides reasonable estimates of
the potential costs and benefits of the
rule. As presented in this section, the
final RIA does indicate that the TC will
bring relatively large quantities of waste
into the subtitle C (system, and also
indicates that there will be attendant
benefits: The Agency used cost and
benefit estimates to compare relative
costs and benefits of the various
regulatory options. The analyses were
conducted separately using approaches
constructed to make the best possible
use of available da;ta. The separate
analyses were not meant to be used to
produce absolute measures of cost
effectiveness. The RIA contains
discussion of the Agency's evaluation
and comparison of cost and benefit
results.
5. Small Business Analysis.
.The Agency received many comments
on its assessment of the effects of the
proposed TC on small businesses. One
group of commentu focused on the
definition chosen by EPA for small
businesses. The Agency was also
criticized for its threshold for
-------
Federal Register / Vol. 55, No. 61 / Thursday, March 29. 1990 / Rules and Regulations
determining if a "substantial number" of
small businesses would suffer
significant economic impacts, and
therefore necessitate the preparation of
a full Regulatory Flexibility Analysis.
Finally, many commenters felt that the
analysis severely underestimated the
impact of the rule on small businesses.
Commenters asked why the Agency
did not use the standard Small Business
Administration (SBA) criterion of 500
employees to define a small business.
The Agency decided to use the 50
employee definition of a small business
because the RIA estimates facility-level
impacts, and the SBA definition applies
to entire firms. In the absence of data to
estimate firm-level impacts, the Agency
chose the 50 employee cutoff as an
appropriate small facility definition for
the RIA. The SBA definition would
designate most of the establishments in
most of the examined industries as
small facilities, which would obscure
differential impacts on smaller facilities.
The Agency was criticized for using a
20 percent threshold for determining if a
"substantial number" of small
businesses would be significantly
affected. Commenters claimed that it
was arbitrary to consider the small
business impact negligible if "only 19.9
percent"'of small business were
Significantly affected. The Agency
recognizes that, for an individual
facility, the magnitude of impacts is not
altered by the number of other facilities
which are significantly affected.
Nevertheless, the Agency believes that
20 percent is a reasonable benchmark
for defining a "substantial number" of
small businesses.- The 20 percent
threshold is commonly applied in RIAs
conducted by EPA.
A large number of commenters
criticized the overall conclusions of the
small business analysis, declaring that
the analysis severely underestimated
the economic effects of the TC on small
businesses. Commenters maintained
that the universe of small businesses
was inadequately addressed. Examples
of small businesses not included in the
analysis which commehters felt should
have been considered included service
stations and vehicle maintenance
facilities. Commenters also mentioned
the expense of performing the TCLP,
claiming that it was an especially
significant hardship for small
businesses.
As explained in the general discussion
of the industrial sectors included in the
RIA, the Agency made extensive efforts
to identify and include sectors
potentially affected by the TC rule,
including end users of products. And, as
discussed under the comments on
incorporating testing costs, these costs
were not included since generators are
not currently required to test their
wastes. Although EPA maintains that a
full RFA is not necessary for the TC
rule, it realizes that the impact of the
rule could be significant for individual
small enterprises.
E. Paperwork Reduction Act
The information collection
requirements in this rule have been
approved by the Office of Management
and Budget (OMB) under the Paper
Reduction Act, 44 U.S.C. 3501 et seq.,
and have been assigned the following
OMB control numbers: 2050-0007, Land
Disposal Permitting Standards; 2050-
0008, RCRA Closure/Post-Closure; 2050-
0009, Hazardous Waste Storage and
Treatment Facilities; 2050-0011,
Contingency Plans for Hazardous Waste
Facilities; 2050-0012, General Facility
Operating Requirements; 2050-0013,
Operating Record for Hazardous Waste
Facilities; 2050-0028, Notification of a
Hazardous Waste Activity; 2050-0033,
Reporting, Recordkeeping, and Planning
for Ground-Water Monitoring; 2050-
0034, RCRA Hazardous Waste Permit
Application Part A; 2050-0036, RCRA
Financial Assurance Requirements;
2050-0037, Recordkeeping and Reporting
for RCRA Permitees; and 2050-0039,
Uniform Hazardous Waste Manifest for
Generators and Transporters.
VII. References
-1. U.S. EPA, "Response to Public Comments
Background Document for the Subsurface
Fate and Transport Model Used in the
Toxicity Characteristic Rule", 1990.
2. U.S. EPA, "Response to Comments
Background Document for the Toxicity
Characteristic", 1983.
3. U.S. EPA, "Technical and Response to
Comments Background Document for
Chronic Toxicity Reference Levels",
1990.
4. U.S. EPA, "Technical and Response to
Comments Background Document for the
TCLP (Method 1311)", 1989.
5. U.S. EPA, "State Subtitle D Regulations on
Solid Waste Landfills", Final Volume I,
1986.
6. U.S. EPA, "National Survey of Solid Waste
(Municipal) Landfill Facilities", Final
Report, EPA/530-SW-88-034,1988.
7. U.S. EPA, "Summary of Data on Industrial
Non-hazardous Waste Disposal
Practices", Final Report, December 1985.
8. U.S. EPA, "Toxicity Characteristic
Regulatory Impact Analysis", 1989.
9. U.S. EPA, "Background Document for
EPA's Composite Landfill Model
, (EPACML)", 1990.
10. Simkins, S. and M. Alexander, "Models
for Mineralization Kinetics with the
Variables of Substrate Concentration
and Population Density", "Applied and
Environmental Microbiology", 1984, Vol.
47, No. 6, pp. 1299-1306.
11. Lewis, D. L. and D. K. Gattie. "Prediction
of Substrate Removal Rates of Attached
Microorganisms and of relative
Contributions of Attached and
Suspended Communities at Field Sites",
"Applied and Environmental
Microbiology", 1988, Vol. 54, No. 2, pp.
434-440.
12. Robinson, J. A. and W. G. Characklis.
"Simultaneous Estimation of Vmax, Km,
and the Rate of Endogenous Substrate
Production (R) from Substrate Depletion
Data", "Microbial Ecology, 1984, Vol. 10,
pp. 165-178.
13. Karickhoff, S. W. "Chapter 11: Sorption
Kinetics of Hydrophobic Pollutants in
Natural Sediments", "Contaminants and
Sediments, Vol. 2: Fate and Transport,
Case Studies, Modeling, Toxicity, Ann
Arbor Science Publishers, Inc. Ann
Arbor, Michigan, 1980. pp. 193-205.
14. Kohring, G., J. E. Rogers and J. Wiegel.
"Anaerobic Biodegradation of 2,4-
Dichlorophenol in Freshwater Lake
Sediments at Different Temperatures",
"Applied and Environmental
Microbiology", 1989, Vol. 55, No. 2, pp.
348-353.
15. Hwang, H., R. E. Hodson, and D. L. Lewis.
"Assessing Interactions^ Organic
Compounds During Biodegradation of
Complex Waste Mixtures by Naturally
Occurring Bacterial Assemblages",
"Environmental Toxicology and
Chemistry", 1989, Vol. 3, pp. 209-214.
16. U.S. EPA, "Screening Survey of Industrial
Subtitle D Establishments", Draft Final
Report, December 1987.
17. U.S. EPA, "Analysis of U.S. Municipal
Waste Combustion Operating Practices",
May 1989.
18. U.S. EPA, "Cooperative Testing of
Municipal Sewage Sludges by the
Toxicity Characteristic Leaching
Procedure and Compositional Analysis",
Draft Final, 1988.
19. U.S. EPA, "Estimates of Waste Generation
by Cellulosic Manmade Fibers, Synthetic
Organic Fibers, Petroleum Refining,
Rubber and Miscellaneous Plastic
Products, Leather Tanning and Finishing,
Oil and Gas Transportation Industries,
and the Laundry, Cleaning and Garment
Services", May 27,1987.
20. U.S. EPA, "Estimates of Waste Generation
by the Lumber and Wood Products
Industry", December 9,1987.
21. U.S. EPA, "Estimates .of Waste Generation
by the Organic Chemical Industry",
December 1987.
22. U.S. EPA, "Estimates of Waste Generation
by Petroleum Crude Oil and Petroleum
Products Distribution and Wholesale
Systems", November 13,1987.
23. U.S. EPA, "Estimates-of Waste Generation
by Plastic Materials and Resins",
November 1987.
24. U.S. EPA, "Estimates of Waste Generation
by the Petroleum Refining Industry",
November 13,1987.
25. U.S. EPA, "Estimates of Waste Generation
by the Pharmaceutical Industry",
November 16,1987.
-------
11862 Federal Register / Vol. 55, No. 61 /
28. U.S. EPA, "Estimates of Waste Generation
by the Pulp and Paper Industry". August
12, 1887.
27.U.S. EPA, "Estimates of Waste Generation
by the Synthetic Fibers Industry".
November 16, 1987.
28. U.S. EPA. "Estimates of Waste Generation
by Textile Mills", December 15, 1987.
20. U.S. EPA. "Synthetic Rubber Industry".
November 1987.
30. US. EPA. "Wastewater Treatment
Profiles for Industrial Sectors Impacted
by Proposed Toxlcity Characteristic".
August 19,1988.
31. VS. EPA, "Wastewater Treatment
Profiles for Industrial Sectors Impacted
by Proposed Toxiclty Characteristic".
August 24. 1988.
32. U.S. EPA. "Liner Location Risk and Cost,
Analysis Model, Phase II", Draft Report,
19(30.
33. U.S. EPA. "Composition and, Management
of Used Oil Generated In the United
States", September 1984.
34. U.S. EPA, "Risk Assessment of Proposed
Waste Oil Standards for the
Management of Used Oil", August 1985.
List of Subjects in 40 CFR Paits 261, 264,
285, 268, 271, and 302
Administrative practice and
procedure. Air pollution control
Chemicals, Confidential business
information, Hazardous materials
transportation, Hazardous substances
Hazardous waste, Indian lands,
Intergovernmental relations, Natural
resources, Nuclear materials. Penalties,
Pesticides and pests, Radioactive
materials, Recycling, Reporting and
recordkeeping requirements, Superfund,
Water pollution control, Water supply.
Waste treatment and disposal.
Dated: March 5. 1990.
William K.Rellly,
Administrator.
For the reasons set out in the
preamble. Chapter I of Title 40 of the
Code of Federal Regulations is amended
as follows:
PART 261— IDENTIFICATION AND
MSTING .OF HAZARDOUS WASTE
l.The authority citation for part. 261
continues to read as follows:
Authority: 42 U.S.C. 6905. 6912(a), 6921, and
2. Section 281,4 is amended by
revising-paragraphs (b){6)(i)
introductory text, and (b)(9) and by
adding paragraph (b)(lQ) to reaias
follows!
§261.4 (Exclusions.
(b) * * '
(6)
(6)(i) Wastes which fail the test' for the
Toxlcity- Characteristjic-because
chromium is present or are" listed in ,
subpart D due to the presence of
chromium, which do not fail the test for
the, Toxicity Characteristic for any other
constituent or are not listed due to the
presence of any other constituent, and
which do not fail the test for any other
characteristic, if it is shown, by a waste
generator or by Waste generators that:
******
(9) Solid waste which consists of
discarded wood or'wood products
which fails the test for the Toxicity
.Characteristic solely for arsenic and
which is not ^hazardous-waste for any
other reason or reasons, if the waste is
generated by persons who utilize the
arsenical-treated wood and Wood
products for these materials' intended
end use. .;
(10) Petroleum-contaminated media
and debris that fail the test for the
Toxicity Characteristic of § 261.24 and
are subject to the corrective action
"regulations under part 280 of this
chapter.
3. Section 261.8 is added to subpart A
to read as follows:
§261.8 PCS Wastes Regulated Under
• Toxic Substance Control Act
The disposal of PGB-containing
dielectric fluid and electric equipment
containing such fluid authorized for use
and regulated under part 761 of this
chapter and that are hazardous only
because they fail (the test for the
Toxicity Characteristic (Hazardous
Waste Codes D018 through D043 only)
are exempt from* regulation under parts
261 through 265, and parts 268,' 270, and
124 of this chapter, .and the notification
requirements of section.SOlO of iRCRA.
4., Section 261.24 is revised to read as
follows:
§261.24 .Toxicity characteristic.
(ajA solid waste exhibits the
cTbfajacterisfic of toxicity if, using the test
meth'6d,s''descrfbed in'Appendix'II or
equivalent methods approved :by the_
Admiriislrator tinder the'procedures set
forth in § § 260.20 and 260.21, the extract
' from a representative sample of the
waste contains any, of the contaminants
listed iniTabTel^at the concentration;:
equa| to'jor'greater than tl^e respective"
value'giyen Jfii that Tab'lfe. Where the
wapte contains less, than 0.5 percent.
fiUe'rable'iolids," the waste itself, after;
filtering using" the methodology outlined
in Appendix If, is considered tb be the
extract for, thie. purpose, of this .section.
(b) A solid'waste that exhibits the
• cliarac|eri'stic.of tpxicity?,but ishqt
listed,as :a hazardous, waste in^subpart
LD,*~has",tKe EPA Hazardous Wa'ste
Number specified in Table 1 which
corresponds to the toxic contaminant
causing it to be hazardous.
TABLE 1.—MAXIMUM CONCENTRATION OF
CONTAMINANTS I-OR THE TOXICITY
CHARACTERISTIC
EPA
HW
No.1
0004
D005
0018
0006
0019
0020
0021
0022 ;
0007
0023
D024
0025
0026
0016
0027
D028
0029,
0030
0012
D031
D032
D033.
D034
0008
D013
D009 ,
D014
0035
D036
D037
0038
0010
D011. .
D039
0016
0040
! fi041
D042/
-Doif
D043
Contaminant
Arsenic
Barium .•. ....
" • w " • •
Benzene.... ........ ....
Cadmium..... ....
Carbon • •
tetrachloride.
Dhlordane
Chlorobenzene
Chloroform.
Chromium
o-Cresol .'...;:!.:
m-Cresol ,
p-Cresol
Cresol.™
24-0 .....
1.4- ;
. Dichloroben-
zene.
1|2-
Dichloroeth-
'ane.
1.1-
Dichloroethy-
lena;
2,4-'
..Dinitrotolueno,
Endrin '
Heptachlor (and
its hydroxide].
Hexachlorbbeh-'
• zene.
Hexachlbrobutji- ,
, , dlend. •
HexachioroeJh
sne.'
.Lead .«...........'
Lindane....
Mercury ...
Methoxychlor
Methyl 'ethyl
•. , ketone.
Nitrobenzene,..,,..
Pehtrachloro- " "
" phenol.
•Pyfiaifie..... r...
Selenium
Silver .:.............i~.
tejraohlbroethyl-
en?- .
Toxaphehe ;...
Trichlqrbethyl-
; erra.
2,4,5,
; Trichldro
phsnol.
2,4^6-
• Trfciilpro-
.Rhahol, ,
Vinyl, cnlbrid(9...*.i.
CAS No.2
7440-38-2
7440-39-3
, 71-43-2
7440-43-9
56-23-5
57-74-9
108-90-7
67-66-3
7440-47-3
95-48-7
108-39-4
106-44-5
• 94-75-7
106-46-7
107-06-2
75-35-4
121-.14-2
'72 20-8
76-44-8
118-74-.1
. 87-68-3
'67-72-1
7439-92-1
58-89-9
7439-97-6
72-43-5
78-93-3
98-95r3
; 87-8.6T5
110-86-1
Z782-49-2
7449^22-^4
42.7-1^-4
• 8001-36-2
' 79-01-6
95-9g-4
.88-06-2
• 93-72-,i'
.75-*>H
Regula-
tory
Level
(mg/L)
5'.0
100.0
0.5
i.o
0.5
0.03
100.0
6.0
sio.
4 200.0
« 200.0
«200.0
« 200.0
10.0
7.5
0.5
0.7
0.13
0.02-
1.008
0.13
0.5.
^3.0
5.0
,.0.4
0.2
10.0
200.0
,2.0
100.0'
'» 5.0
• IX)
5.0
0.7
'0.5
0.5
400.6
'2.0.
.1.0
0-2
• « Hazardoiiis v#£ste miiJTiber, !..
^Chemical abstracts service qumbjr.
" ' » QuantifeHon' limit is greater than the. calculated
regulatory level. ..The' quarititatibn "limit .therefore' ber
comes -the fegujaVoty level.
- '.' «lf b-.:rtK and'p-Creaolicbricwntratioh^icannot'be
; differentiated^ tha. total rtesol ; '
-------
Federal Register /Vol. 55., No. 61 / Thursday, March 29, 1990 / Rules and Regulations
11863
5. Section 261.30 is amended by
revising paragraph (b) to.read as
follows:
§261:30 General.
*****
(b] The Administrator will indicate his
basis for, listing the classes or types of
wastes listed in this subpart by
employing one or more of the following
Hazard Codes:
Ignitable Waste (I)
Corrosive Waste (CJ
Reactive Waste (R)
Toxicity Characteristic Waste. (E)
Acute Hazardous Waste (H)
Toxic Waste (T)
Appendix VII identifies the constituent
which caused the Administrator to list
the waste as a Toxicity Characteristic
Waste (E) or Toxic Waste (T) in
§§261.31 and 261.32:
* * * * *
6. Appendix II of par» 261 is revised to
read as follows:
Appendix II—Method 1311, ToxicUy
Characteristic Leaching Procedure
(TCLP)
1.0 Scope and Application
1.1 . The TCLP is designed to determine the
mobility of both organic and-inorganic
contaminants present in liquid, solid; and
multiphasic wastes.
1.2 If a total analysis of the waste
demonstrates that individual contaminants
are not present in the waste, or that they are
present but at such low concentrations that
the appropriate regulatory thresholds could
not possibly be exceeded, the TCLP need not
be run.
1.3 If an analysis of any one of the liquid
fractions of the TCLP extract indicates that a
regulated compound is present at such high
levels that even after accounting for dilution
from the other fractions of the extract the
concentration would be above the regulatory
threshold for that compound, then the waste
is hazardous and it is not necessary to
analyze the remaining fractions of the
extract.
1.4 If an analysis of extract obtained
using a bottle extractor shows that the
concentration of any regulated volatile
contaminant exceeds the regulatory threshold
for that compound, then the waste is
hazardous and extraction'using. the ZHE.is
not necessary. However, extract from a bottle
extractor cannot be used to demonstrate tha*
the concentration of volatile compounds is
below the regulatory threshold. ' '
2.0 Summary of Method (see Figure 1)
2.1 For liquid wastes (i.e., those
containing less than 0.5 percent dry solid
material), the waste, after filtration through a
0.6 to 0.8-um glass fiber filter, is defined as
the TCLP extract.
2.2 For wastes containing greater than or
equal to 0.5 percent solids, the liquid, if any,
is separated from the solid phase and stored
for later analysis; the solid phase, if
necessary, is reduced in particle size. The
solid phase is extracted with an amount of
extraction fluid equal to 20 times the weight
of the solid phase. The extraction fluid
employed is a function of the alkalinity of the
solid phase of the waste. A special extractor
vessel is used when testing for volatile
contaminants (see Table 1 for a list of volatile
compounds). Following extraction, the liquid
extract is separated from the solid-phase by
filtration through a 0.6 to 0.8-um glass fiber
filter.
BILLING CODE 6560-50-M
-------
1 MetKa"d,'13U Flowchart
Use a »ub-»aople of want*
Separate liquid
• * [rout aolid* .
with 0.6-0.8 urn
glass fibar,
filt«r
Extract
w/appcopriat* fluid
1) Extractor w/cagc
: for non-volati.l«>
2} ZHE d.vic. for
vblatil»'
Yes
la
liquid
compatibla
with the
extract?
Diaoacd
• slid
Solid
'•Separate, extxact
'•froa iolid w/ .
O.G-O.&'-ua 'gla»a
• fiber 'filter
Measure amount of
liquid and ariily?o
(mathematically
combine .result w/
result of extract'.
Liquid
I* the
extract
compatible w/
liquid phase of
the wade?
Combing.
ax tract w/
liquid" ' phasa
of wa»t«
Anaiyza.
liquid
-------
Federal
/ ;:VdL. 55.: No. 61 / Thursday, March 29; 1990L / Rules and Regulations 1^865
TABLE i.—VOLATILE CONTAMINANTS * TABLE 1 .-
Compound.
Acetone ,
. Benzene...:...........
, nrButyt alcohol'; .-. '.
' Carbon disulfide^..™.™.;...... : •
Carbon tetrachloride.... ;.....,
Chlorobenzene..................... .,..;...
Chloroform.....:. ,.,.., .........
1 iS-Dichlbroethahe „..
•f.l-Dtohloroethylehe ...... '. .
Ethyl acetateL...;....: . u^..;-,.;*.-.
Ethyl: benzene . • . .
Isobutanol. .....„„ „.
Methaiiol... ;.... „.. .™.^.m.,.:
Methyierie chloride1..,.... .;„...,„.
Methyl lethylfeetone. ..„ ,....„...:
Methyl isobutyl ketone...
Tetrachloroethylene ......;....„ „.,;
Toluene....,:..;.... ::i . ...
1,1,1-TftehloroBtnarie.
TrichlofoBthyfene:,.:.:...;..........,.; :..:
Trichlorofluoromethane. ...:^ ....,;.
1.1^-Trichlor6-1^-trifluoroethane :...;..
Vinyl .chloride..............: — .,......, .......
CAS no.
67-64-1
71^36-3
75^15-0
56-23r5
67-66-3
107-06-2
75-35-^
14i-78r6
1bct4l-4
• ,60-29^7
67-56-1
75-O9-2
78^93-3
108-10-1
127^-18-4
108-88-3
• '71-55-6
79-01-6
75-69-4
76-13-1
75-01-4
Continued
Xyiene.....
Compound
CAS no.'
1330^20-7
' When testing for any or all of these contami-
riarts, the zero-headspace extractor vessel shall be
Used Instead of the bottle extractor, '
2.3 If compatible (i.e., multiple;phases Will
not form on combination), the initial liquid
phase of the waste is added to. the liquid
extract, and these are analyzed .tpgetier. If
incompatible, the liquids are analyzed
separately and the results &re mathematically
combined to |yield a vbiumi?-weighted
average concentration.
3.0 -rhterfererices
3.1 Potential fnterferences that may be ,
encountered during analysis are discussed.in
the individual analytical methods.,
4.0 Apparatus and Materials ' .• '
4.1; Agitation apparatus: The agitation
apparatus must be capable of rotating the
extraction vessel in an end-over-end fashion
(see Figure 2) at 30+2 rpm. Suitable devices
known to EPA are identified in Table 2. '
4.2 Extraction Vessel: , ,
,4.2.1 , Zero-Headspace Extraction Vessel
, (ZHE). This device is for use only when the
Waste is being tested for the mobility of
volatile constituents (i.e., those listed in
table 1). The ZHE (depicted in Figure 3)
allows for liquid/solid separation within the
device, and effectively precludes headspace.
This type of vessel allows for initial liquid/
solid separation, extraction, and final extract
filtration Without opening the vessel (see step'
4.3.1). The vessels shall have an internal
volume of 500^600 mL and be. equipped to .
, accommodate a 90-110 mm filter. The devices
contain VITON R ' Q-rings which should be
replaced frequently.; Suitable ZHE devices
known to EPA are identified in fable 3.
BILLING CODE 5360-50-M
i VJTON B is a trademark of Du Pont.
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«'frtfift Federal Register /, Vol. 55, No. 61 / Thursday March 29, 1990 / Rules and Regulations
Motor
(30 ± 2rpm)
Extraction Vessel Holder
Rgure 2. Rotary Agitation Apparatus
BIIUNQ CODE (5«O-SO-C
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Federal Register /-Vol. 55; No; 61 / Thursday. March 29; 1990 / Rules and Regulations
11867
TABLE 2.—SUITABLE ROTARY AGITATION APPARATUS
Company
Analytical Testing and Consulting Services, Inc.....
Associated Design and Manufacturing Company.,
Environmental Machine and Design, Inc .-,
IRA Machine Shop and Laboratory ,
Lars Lande Manufacturing „.;.:„.„..„
Millipore Corp....;,
Location
Warrington, PA (215) 343-4490..
Alexandria. VA (703) 549-5999.
Lynchburg, VA (804) 845-6424.
Santuree, PR (809) 752-4004....,
Whitmore Lake, Ml (313) 449-
4116.
Bedford, MA (800) 225-3384......
Model no.
2-ZHE or 4'bottle extractor (DC20S); 4-2HE or
8-bottle extractor (DC20); 6-ZHE or 12-bottle
, extractor (DC20B). .
2-vessel (3740-2). 4-vessel (3740-4). 6-vessel
(3740-6). 8-vessel (3740-8). 12-vessel
(3740-12). 24-vessel (3740-24).
8-vessel (08-00-00). 4-vessel (04-00-00).
8-vessel (011001).
10-vessel (10VRE). 5-vessel (5 VRE).
4-ZHE or 4 Miter bottle extractor
(YT300RAHW).
1 Any device that rotates the extraction vessel in an end-over-end fashion at 30 +2 rpm is acceptable.
BILLING CODE 6560-50-M
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11868 Federal Register f Vol. 55. No. 61 / Thursday. March 29. 1990 / Rufes and Regulations
Liquid Inlet/Outlet Valve
Top Flange—*
Support Scree
Support Sereei
Vlton
Bottom Range
Pressurized Gas
Inlet/Outlet Valve
Pressure
Gauge
Figure 3. Zero-Headspace Extractor (ZHE)
BrtJLWa COM 6E90-50-C
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Federal Register / Vol. 55, No. 61 / Thursday, March 29, 1990 / Rules and Regulations 11869
TABLE 3.—SUITABLE ZERO-HEADSPACE EXTRACTOR VESSELS l
Company
Analytical Testing & Consulting Services, Inc......... ..
Associated Design and Manufacturing Company ".....,
Lars Lands Manufacturing z . .
Millipore Corporation ,.......-. :...;... . ;
Environmental Machine and Design, Inc ;'. '.. ..;.. ' , ' '
Location
Warrington PA (215) 343-4490
Alexandria, VA (703) 549-5999
Whitmore Lake Mi (313) 449-
4116.
Bedford MA (800) 225-3384
Lyncriburg, VA (804) 845-6424
Model no.
•YT^nnQOHW ftflQ Procure npuirA
VOLA-TOX1 Gas Gas Pressure Device
1 Any device that meets the specifications listed in Section 4.2.1 of the method is suitable. •
2 This device uses a 110 mm filter.
For the ZHE to be acceptable-for use, the
piston within the ZHE should be able to be
moved with approximately 15 psi or less. If it
takes more pressure to move the piston, the
O-rings in the device should be replaced. If
this does not solve the problem, the ZHE is
unacceptable for TCLP analyses and the
manufacturer should be contacted.
The ZHE should be checked for leaks after
every extraction. If the device contains a
built-in pressure gauge, pressurize the device
to 50 psi, allow it to stand unattended for 1
hour, and recheck the pressure. If the .device
does not have a built-in pressure gauge,
pressurize the device to SO psi, submerge it in
water, and check for the presence of air
• bubbles escaping from any of the fittings. If
pressure is lost, check all fittings and inspect
and replace O-rings, if necessary. Retest the
device. If leakage problems cannot be solved,
the manufacturer should be contacted.
, Some ZHEs use gas pressure to actuate the
ZHE piston, while others use mechanical
pressure (see Table 3). Whereas the volatiles
procedure (see section 9.0) refers to pounds-
per-square-inch (psi), for the mechanically
actuated piston, the pressure applied is
measured in torque-inch-pounds. Refer to the
manufacturer's instructions as to the proper
conversion.
4.2.2 Bottle Extraction Vessel. When the
waste is being evaluated using the
nonvolatile extraction, a jar with sufficient
capacity to hold the sample and the
extraction fluid is needed. Headspace is
allowed in this vessel.
The extraction bottles may be constructed
from various materials, depending on the
contaminants to be analyzed and the nature
of the waste (see Step 4.3.3). It is
recommended that borosilicate glass bottles
be used instea'd of other types of-glass,
especially "when inorganics are of concern.
Plastic bottles, other than polytetrafluoro-
ethylene, shall not be used if organics are to
be investigated. Bottles are available from a
number of laboratory suppliers. When this
type of extraction vessel is used, the filtration
device discussed in Step 4.3.2 is used for
initial liquid/solid separation and final
extract filtration.
4.3 Filtration Devices: It is recommended
that all nitrations be performed in a hood.
4.3.1 Zero-Headspace Extractor Vessel
(ZHE): When the waste is evaluated for
volatiles, the zero-headspace extraction
vessel described in section 4.2.1 is used for
filtration. The device shall be capable of
supporting and keeping in place the glass
fiber filter and be able to withstand the
pressure needed to accomplish separation (50
psi).
Note: When it is suspected that the glass
fiber filter has been ruptured, an in-line glass
fiber filter may be used to filter the material
within the ZHE.
4.3.2 Filter Holder: When the waste is
evaluated for other than volatile compounds,
any filter holder capable of supporting a glass
TABLE 4.—SUITABLE FILTER HOLDERS '
fiber filter and able to withstand the pressure
needed to accomplish separation may be
used. Suitable filter holders range from
simple vacuum units to relatively complex
systems capable of exerting pressures of up
to 50 psi or more. The type of filter holder
used depends on the properties of the
material to be filtered (see Step 4.3.3). These
devices shall have a minimum internal
volume of 300 mL and be equipped to
accommodate a minimum filter size of 47 mm
(filter holders having an internal capacity of
1.5 L or greater and equipped to
accommodate a 142 mm diameter filter are
recommended). Vacuum filtration can only be
used for wastes with low solids content (<10
percent) and for highly granular liquid-
containing wastes. All other types of wastes
should be filtered using positive pressure
nitration. Suitable filter holders known to
EPA are shown to Table 4.
4.3.3 Materials of Construction:
Extraction vessels and filtration devices shall
be made of inert materials which will not
leach or absorb waste components. Glass,
polytetrafluoroethylene (PTFE), or type 316
stainless steel equipment may be used when
evaluating the mobility of both organic and
inorganic components. Devices made of high-
density polyethylene (HOPE), polypropylene,
or polyvinyl chloride may be used only when
evaluating the mobility of metals. Borosilicate
glass bottles are recommended for use over
other types of glaSs bottles, especially when
inorganics are constituents of concern.
Company
Nucleopora Corporation., ............. .... „
Micro Filtration Systems _.. , ._......_.....„
Millipore Corporation _ „ „
Location
Pleasanton, CA (800) 882-7711
Dublin, CA (800) 334-7132 (415) 828-6010...
Bedford, MA (800) 225-3384
Model/Catalogue no.
425910 410400 . . _
302400311400
YT30142HW XX1004700
'Size (urn)
47 mm
47mm
47 mm
recommended
an^lyze
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Federal Register / Vol. 55, No. 61 / Thursday, March 29; 1990/ Rutes and Regulations
TABLE 5'.—SUITABLE FILTER MEDIA
Company
MiKpore Corporation
Nucteopore Corporation. — ~
Whatman Laboratory Products, Inc
Micro Fitt/ation Systems ...... :~ :
Location
Pleasanton, CA (415) 463-2530
Dublin, CA (800) 334-7132 (415) 828J6010
Model ;
AP40
211625
Pore size
0.7
0.7
0.7
0.7
«Any fitter that moots the specifications in Section 4.4 of the Method is suitable.
4.0 ZHE extract collection devices:
TEDLAR" bogs or glass, stainless steel or
PTFE gas-tight syringes are used to collect
the Initial liquid phase and the final extract of
the waste when using the ZHE device. The.
devices listed are recommended for use
under tho following conditions:
4.6.1 If a waste contains an aqueous
liquid phase or if a waste does not contain a
significant amount of nonaqueous liquid (i.e.,
<1 percent of total waste), the TEDLARR bag
or a 600 mL syringe should be used to collect
and combine the initial liquid and solid
extract.
4.0,2 If a waste contains a significant
amount of nonaqueous liquid in the initial
liquid phase (i.e., >1 percent of total waste),
tho syringe or the TEDLARR bag may be used
for both the initial solid/liquid separation
and the final extract filtration. However,
analysts should use one or the other, not
both.
4,0.3 If the waste contains no initial liquid
phase (Is 100 percent solid) or has no
significant solid phase (is 100 percent liquid),
cither the TEDLAR* bag or the syringe may
bo used. If the syringe is used, discard the
first 5 mL of liquid expressed from the device.
Tho remaining aliquota are used for analysis.
4.7 ZHE.extraction fluid transfer devices:
Any device capable of transferring the
extraction fluid into the ZHE without
changing the nature of the extraction fluid is
acceptable (e.g., a positive displacement or
peristaltic pump, a gas tight syringe, pressure
filtration unit (See Step 4.3.2), or other ZHE
device).
4.8 Laboratory balance: Any laboratory
balance accurate to within +0.01 grams may
ba used (all weight measurements,are to be
within -f 0.1 grams).
5.0* Reagents
6.1 Reagent water. Reagent water is
defined as water in which an interferant is
not observed at or above the methods
detection limit of the analyte(s) of interest.
For nonvolatile extractions, ASTM Type II
water or equivalent meets the definition of
reagent water. For volatile extractions;'!! is
recommended that reagent water be
generated by any of the following methods.
Reagent water should be monitored
periodically for impurities.
5.1.1 Reagent water for volatile
extractions may be generated by passing tap
water through a carbon filter bed containing
about 500 grams of activated carbon (Calgon
Corp., Filtrasorb-300 or equivalent).
5.1.2 A water purification system
(Millipore Super-Q or equivalent) may also be.
used to generate reagent water for volatile
extractions!
• TEDLAR" U a registered trademark of Du Pont.
5.1.3 Reagent water for volatile
extractions may also be prepared by boiling
water for 15 minutes. Subsequently, while
maintaining the water temperature at 90 +5
°G, bubble a contaminant-free inert gas (e.g.,
nitrogen) through the water for 1 hour. While
still hot, transfer the water to a narrow mouth
screw-cap bottle under zero-headspace and
seal with a Teflon-lined septum and cap.
5.2 Hydrochloric acid (IN), HC1, made
from ACS reagent grade.
5.3'' Nitric acid (IN), HNCfe, made from
ACS reagent grade.
5.4 Sodium hydroxide (IN), NaOH, made
from ACS reagent grade;
5.5 Glacial acetic acid, HOAc, ACS
reagent grade. .
5.6 Extraction fluid.
5.6.1 Extraction fluid #1: Add 5,7 mL
glacial HOAc to 500 mL of the appropriate
water (See Step 5.1), add 64.3 mL of IN
NaOH; and dilute to a volume of 1 liter.
When correctly prepared, the pH of this fluid
will be 4.93+0.05.
5.6.2 Extraction fluid #2: Dilute 5.7 mL
glacial HOAc with ASTM Type II water (See
Step 53) to a volume of 1 liter. When
correctly prepared, the pH of this fluid will be
2.88+0.05.
Note: These extraction fluids should be
monitored frequently for impurities. The pH .
should be'checked prior to use to ensure that
these fluids are made up accurately. If
impurities are found or the pH is not within
the above specifications, the fluid shall be
discarded and fresh extraction fluid
prepared.
5.7 Analytical standards prepared
according to the appropriate analytical
method.
6.0 Sample Collection, Preservation, and
Handling
6.1 All samples shall be collected using
an appropriate sampling plan.
6.2 The TCLP may place requirements on
the minimal size of the field sample
•depending upon the physical state or states of
•the waste and the contaminants of concern.
An aliquot is needed for preliminary
evaluation of which extraction fluid is to be
used for the nonvolatile contaminant
extraction procedure. Another aliquot may be
needed to actually conduct the nonvolatile
extraction (see section 1.4 concerning the use
of this extract for volatile ofganics). If
'volatile organics.are of concern, another,
aliquot may be needed. Quality control
measures may-require additional aliquots.
Further, it is always wise to collect more
sample just in case something goes wrong
with the initial attempt to conduct the test.
6.3 Preservatives shall not be adde'd to
samples.
6.4 • Sample's may be refrigerated unless
refrigeration results: in irreversible physical
change to the waste. If precipitation occurs,
the entire sample (including precipitate).
should be extracted.
6.5 -When the waste is to be evaluated for
volatile contaminants, care shall be taken to
minimize the loss of volatiles.,Samples shall
be taken and stored in a manner to prevent
the loss of volatile contaminants (e.g.,
samples should be collected in Teflon-lined
septum capped vials arid stored at 4 °C, until
ready to be opened prior to extraction).
6.6 TCLP extracts should be prepared for
analysis and analyzed as soon as possible
following extraction. Extracts or portions of
extracts for metallic contaminant
determinations must be acidified with nitric
acid to-a pH <2, unless precipitation occurs
(see section 8.14 if precipitation occurs).
Extracts or portions of extracts for organic
contaminant detenninations shall not be
allowed to come into contact with the
atmosphere (i.e., no headspace) to prevent
losses. See section. 10.0 (QA requirements) for
acceptable sample and extract holding times,
7.0 ' Preliminary,Evaluations
Perform preliminary TCLP evaluations on a
minimum 100 gram aliqout of waste. This
aliquot may not actually undergo TCLP
extraction. These preliminary evaluations
include: (1) determination of the percent
solids; (2) determination of whether the waste
contains insignificant solids and is, therefore,
its own extract after filtration; (3)
determination of whether the solid portion of
the waste requires particle size reduction;
and (4) determination of which of the two
extraction fluids aire to be used-for the
nonvolatile TCLP extraction of the waste.
7.1 Preliminary determination of percent
solids: Percent solids is defined as that,
fraction of a waste sample (as a percentage
of the total sample) from which no liquid may
be forced out by an applied pressure, as
described below. •
" 7.1.1 If the waste will obviously yield no
free liquid when subjected to pressure
filtration (i.e:, is 100% solids) proceed to Step
7.3.
7.1.2 If the sample is liquid or multiphasic,
liquid/solid separation to make a preliminary
determination of percent solids is required.
This involves the filtration device described
in Step 4.3.2 and Ui outlined in Steps 7.1.3'
through 7.1.9.
7.1.3 Pre-weigh the filter and the
container that will, receive the filtrate.
7.1.4 Assemble the filter holder and filter
following the manufacturer's instructions.
Place the filter on the support screen and
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Federal Register / Vol. 55, No. 61 / Thursday, March 29. 1990 / Rules and Regulations 11871
7.1.5 Weigh out a subsample of the waste
'100 gram minimum) and record the weight.
' 7.1.6 Allow slurries to stand to permit the
solid phase to settle. Wastes that settle
slowly may be centrifuged prior to nitration.
Centrifugation is to be used only as an aid to
filtration. If used, the liquid should be
decanted and filtered followed by filtration of
the solid portion of the waste through the
same filtration system.
7.1.7 Quantitatively transfer the waste
, sample to the filter holder (liquid and solid
phases). Spread the waste sample evenly
over the surface of the filter. If filtration of
the waste at 4 °G reduces the amount of
expressed liquid over what would be
expressed at room temperature then allow
the sample to warm up to room temperature
in the .device before .filtering.
Note: If waste material (>1 percent of
original sample weight) has obviously
adhered to the container used to transfer the
sample to the filtration apparatus, determine
the'weight of this residue and subtract it from
the sample weight determined in Step 7.1.5 to
determine the weight of the waste sample
that will be filtered.
Gradually apply vacuum or gentle pressure
of 1-10 psi, until .air or pressurizing gas moves
through the filter. If this point is not reache-
under 10 psi, and if no additional liquid has
passed through the filter in any 2-minute
interval, slowly increase the pressure in 10-
psi increments to a maximum of 50 psi. After
each incremental increase of 10-psi, if the
pressurizing gas has not moved through the
filter, and if no additional liquid has passed
through the filter in any 2-minute interval,
proceed to the next 10-psi increment When
the pressurizing gas begins to move through
the filter, or when liquid flow has ceased at
50 psi (i.e., filtration does not result in any
additional filtrate within any 2-minute
period), stop the filtration.
' Note: Instantaneous application of high
pressure can degrade the glass fiber filter and
may cause premature plugging.
7.1.8 The material in the filter holder is
defined as the solid phase of the waste, and
the filtrate is defined as the liquid phase.
Note: Some wastes, such as oily wastes
and some paint wastes, will obviously
contain some material that appears to be a
liquid. Even after applying vacuum or,
pressure filtration, as outlined in Step 7.1.7,
this material may not filter. If this is the case.
the material within the filtration device is
defined as a solid. Do not replace the original
filter with a fresh filter under any
circumstances. Use only one filter.
7.1.9 Determine the weight of the liquid
phase by .subtracting the weight of the filtrate
container (see Step 7.1.3) from the total
weight of the filtrate-filled container.
Determine the weight of the solid phase of
the waste sample by subtracting the weight
of the liquid phase from the weight of the
total waste sample, as determined in Step
7.1.5 or 7.1.7.
Record the weight of the liquid and solid
phases. Calculate the percent solids as
follows:
Percent solids = •
Weight of solid (Step 7.1.9)
Total weight of waste (Step 7,1.5 or 7.1.7)
•X100
7.2 If the percent solids determined in
Step 7.1.9 is equal to or greater than 0.5%,
then proceed either to Step 7.3 to determine
whether the solid material requires particle
size reduction or to Step 7.2.1 if it is noticed
that a small amount of the filtrate is
entrained in wetting of the filter. If the
percent solids determined in Step 7.1.9 is less
than 0.5%, then proceed to Step 8.9 if the
nonvolatile TCLP, is to be performed and to
section 9.0 with a fresh portion of the waste if
the volatile TCLP is to be performed.
7.2.1 Remove the solid phase and filter
from the filtration apparatus.
7.2.2 Dry the filter and solid phase at 100
+20 °C until two successive weighing yield
the same value within +1 percent. Record
the final weight.
Note: Caution should be taken to ensure
that the subject solid will not flash upon
heating. It is recommended that the drying
oven be vented to a hood or other
appropriate device.
7.2.3 Calculate the percent dry solids as
follows:
Percent dry solids
(Weight of dry waste+filter)—tared weight of filter
Initial weight of waste (Step 7.1.5 or 7.1.7)
X 100
7.2.4 If the percent dry solids is less than
0.5 percent, then proceed to Step 8.9 if the
nonvolatile TCLP is to be performed, and to
Section 9.0 if the volatile TCLP is ^> be
performed. If the percent dry solids is greater
than or equal to 0.5%, and if the nonvolatile
TCLP is to be performed, return to the
beginning of this Section (7.0) and, with a
fresh portion of waste, determine whether
particle size reduction is necessary (Step 7.3)
and determine the appropriate extraction
fluid (Step 7.4). If only the volatile TCLP is to
be performed, see the note in Step 7.4.
7.3 Determination of whether the waste
requires particle-size reduction (particle-size
is reduced during this step): Using the solid
portion of the waste, evaluate the solid for
particle size. Particle-size reduction is
required, unless the solid has a surface area
per gram of material equal to or greater than
3.1 cm2, or is smaller than 1 cm in its
narrowest dimension (i.e., is capable of
passing through a.9.5 mm (0.375 inch)
standard sieve). If the surface area is smaller
or the particle size larger than described
above, prepare the solid portion of the waste
for extraction by crushing, cutting, or grinding
the waste to a surface area or particle-size.as
described above. If the solids are prepared
for organic volatiles extraction, special
precautions must be taken, see Step 9.6.
Note: Surface area criteria are meant for
filamentous (e.g., paper, cloth, and similar)
waste materials. Actual measurement of
surface area is not required, nor is it
recommended. For materials that do not
obviously meet the criteria, sample-specific
methods would need .to be developed and
employed to measure the surface area. Such
methodology is currently not available.
7.4 ' Determination of appropriate
extraction fluid: If the solid content of the
waste is greater than or equal to 0.5 percent
and if TCLP extraction for nonvolatile
constituents will take place (Section 8.0),
perform the determination of the appropriate
fluid (Step 5.6) to use for the nonvplatiles
extraction as follows:
Note: TCLP extraction for volatile
constituents uses only extraction fluid #1
(Step 5.6.1). Therefore, if TCLP extraction for
nonvolatiles is not required, proceed to
Section 9.0.
7.4.1 Weigh out a small subsample of the
solid phase of the waste, reduce the solid (if
necessary) to a particle-size of approximately
1 mm in diameter or less, and transfer 5.0
grams of the solid phase of the waste to a
500-mL beaker or Erlenmeyer flask.
7.4.2 Add 96.5 mL of reagent water'
(ASTM Type II) to the beaker, cover with a
watchglass, and stir vigorously for 5 minutes
using a magnetic stirrer. Measure and record
the pH. If the pH is <5.0, use extraction fluid
#1. Proceed to Section 8.0.
7.4.3 If the pH from Step 7.4.2 is > 5.0, add
3.5 mL IN HC1, slurry briefly, cover with a
watchglass, heat to 50 °C, and hold at .50 *C
for 10 minutes.
7i4.4 .Let-the solution cool to room
temperature and record the pH. If the pH is
<5.0, use extraction fluid #1, If the pH is
>5.0, use extraction fluid #2. Proceed to
Section 8.0.
7.5 If the aliquot of the waste used for the
preliminary evaluation (Steps 7.1—7.4) was
determined to be 100% solid at Step 7.1.1,
then it can be used for the Section 8.0
extraction (assuming at least 100 grams
-------
11872 ...... Federal Register
remain], and the section 9.0 extraction. ,, .
(assuming at least 25 grams remain). If the
aliquot was subjected to the procedure in
Step 7.1.7, then another aliquot shall be used '
for tho volatile extraction procedure in
Section 9.0. Hie aliquot of th'e'waste
subjected to the procedure in Step 7.1.7 might
bo appropriate for use for the section 8,0
extraction if an adequate amount of solid (as
determined by Step 7.1.9) was obtained. The '
amount of solid necessary is dependent upon
whether a sufficient amount of extract will be
produced to support the analyses. If an •
adequate amount of solid remains, proceed to
Step 8.10 of the nonvolatile TCLP extraction.
8,0 Procedure When Volatiles Are Not
Involved
A minimum sample size of 100 grams (solid
and liquid phases) is required. In some cases,
a larger sample size may be appropriate,
depending on the solids content of the waste
sample (percent solids. See Step 7.1),'whether
the initial liquid phase of the waste will be
mlsclble with the aqueous extract of the
solid, and whether inorganics, aemivolatile
organlcs, pesticides, and herbicides are all
analytes of concern. Enough solids should be
generated for extraction such that the volume
of TCLP extract will be sufficient to support
all of the analyses required. If the amount of
extract generated by a single TCLP extraction
will not be sufficient to perform all of the
analyses, more than one extraction may be
performed and the extracts from each
combined and aliquoted for analysis.
0.1 If the waste will obviously yield no
liquid when subjected to pressure filtration
(i.e., is 100 percent solid, see Step 7.1), weigh,
out a sul sample of the waste (100 gram
minimum) and proceed to Step 8.9. •
8,2 If the sample is liquid or multiphaslc,
liquid/solid separation is required. This
involves the filtration device described in
Step 4.3,2 and is outlined in Steps 8.3 to 8.8.
0.3 Pre-weigh the container that will
receive the filtrate.
8.4 Assemble the filter holder and filter
following the manufacturer's instructions.
Place the filter on the support screen and
secure. Acid wash the filter if evaluating the
mobility of metals (see Step 4.4). .
Note: Acid washed filters may be used for
all nonvolatile extractions even when metals
are not of concern.
8.5 Weigh out a subs.ample of the waste.'
(100 gram minimum) and record the weight If
the waste contains <0.5 percent dry solids
(Step 7,2), the liquid portion of the.waste, -
after filtration, is defined as the TCLP .
extract. Therefore, enough of the sample
should be filtered so that the amount of
filtered liquid will support all. of the analyses
required of the TCLP extract. For wastes
containing >0.5 percent dry solids (Step 7.1
or 7.2), use the percent solids information
obtained in Step 7.1 to determine the , <
optimum sample size (100 gram minimum) for
'filtration. Enough solids should be generated
by filtration to support the analyses to be
performed on the TCLP extract
8.6 Allow slurries to stand to permit the
solid phase to settle. Wastes that settle
slowly may be centrifuged prior to filtration.
Use centrifugation only as an aid to filtration-.
If the waste is centrifuged, the liquid should
be decanted and filtered followed by
filtration of the solid portion of the waste
through the same filtration system.
8.7 Quantitatively transfer the waste
sample (liquid and solid phases) to the filter
holder (see Step 4.3.2). Spread the waste
sample evenly over the surface of the filter. If
filtration of the waste at 4 °C reduces the
amount of expressed liquid over what would
be expressed at room temperature, then
allow the sample to warm up to room
temperature in the device before filtering.
Note: If waste material (>1 percent of the
original sample weight) has obviously
adhered to the container used to transfer the
sample to the filtration apparatus, determine
the weight of this residue and subtract it from
the sample weight determined in Step 8.5, to "
determine the weight of the waste sample
that will be filtered.
Gradually apply vacuum or gentle pressure
•pf 1-10 psi, until air or pressurizing gas moves
through the filter. If this point is .not reached
under 10 psi, and if no additional liquid has
passed through the filter in any 2-minute
interval, slowly increase the pressure in 10-
psi increments to a maximum of 50 psi. After
each incremental increase of 10 psi, if the
pressurizing gas has not moved through the
filter, and if no additional liquid has passed
through the filter in any 2-minute interval,
proceed to the next 10-psi increment. When
the pressurizing gas begins to move through
the filter, or when the liquid flow has ceased
at 50 psi (i.e.,-filtration does not result in any
additional filtrate within- a 2-minute period),
stop the filtration. , .
Note: Instantaneous application of high
pressure can degrade the glass fiber filter and
may cause premature plugging.
8.8 The material in the filter holder is
defined as the solid phase of the waste, and
the filtrate is defined as the liquid phase.1
Weigh the filtrate. The liquid phase may now
be either analyzed (See Step 8.12), or 'stored at •
4 °C un'til time of analysis.
Note: Some wastes, such as oily wastes
and some paint wasites, will obviously
contain some, material that appears to be a
liquid. Even after applying vacuum,or . ,
pressure filtration, as outlined in Step 8.7, this
material may not filter. If this is the case, the
material within the filtration device is
defined as a solid and is carried through .the
'extraction as-a solid. Do not replace the
original filter with a fresh filter under any
circumstances.vUse only one filter,
, 8.9 If the waste icbntains <0.5 percent dry
solids (s.ee Step 7.2), proceed to Step 8.13. If •
the waste contains >0.5 percent dry solids
(see ;Step 7.1 or 7.2), and if particle-size
reduction of the solid was needed in Step 7.3,
proceed to Step 8.10. If the waste as received
passes a 9.5 nun sieve, quantitatively transfer
the solid material into the extractor bottle
along with the filter used to separate the
initial liquid from the solid phase, and
proceed to'Step 8.11."
8.10 Prepare the solid portion of the waste
for extraction by crushing, cutting, or grinding
the waste to a surface area or particle-size as
described in Step 7.3. When the surface area
or particle-size has been, appropriately
altered, quantitatively transfer the solid
material into an extractor bottle. Include the
filter used to separate the initial liquid from
the solid phase.
Note: Sieving of fee waste is not normally
required. Surface area requirements are
meant for filamentous (e.g., paper, cloth) and
similar waste materials. Actual measurement
pf surface area is-not recommended. If
sieving is necessary, a Teflon-coated sieve
should be used to avoid contamination of the
sample.
8.11 Determine l:he amount of extraction
fluid to add to the extractor vessel as follows:
Weight of extraction fluid
20Xpercent solids (Step 7.1)Xweight of waste filtered (Step 8.5 or 8.7)
100
Slowly add this amount of .appropriate
extraction fluid (see Step 7.4) to the extractor
vessel. Close the extractor bottle tightly (it is
recommended that Teflon tape be used to
ensure a tight seal), secure in rotary agitation
device, and rotate at 30+2 rpm for 18+2
hours. Ambient temperature (i.e., temperature
of room in which extraction takes place) shall
be maintained at 22 +3 *C during the
extraction period.
Note: As agitation continues, pressure may
build up within the extractor bottle for some.
types of wastes (e.g., limed or calcium
carbonate containing waste may evolve
gases such as carbon dioxide). To relieve
excess pressure, the extractor bottle may.be
periodically opened (e.g., after 15 minutes, 30
minutes, and 1 hour) and vented into a hood.
8.12 Following the 18+2 hour extraction,
separate the material in the extractor vessel
into its component, liquid and solid phases by
filtering through a new glass fiber filter, as
outlined in Step 8.7. For final filtration pf the
TCLP extract, the glass fiber filter may be
changed, if necessary, to facilitate filtration.
Filters) shall be acid-washed (see Step 4.4) if
evaluating the mobility of metals.
8.13 Prepare the TCLP extract as follows:
8.13.1 If the waste contained no initial
liquid phase, the filtered liquid material.
obtained from Step 8.12 is defined as the
TCLP extract. Proceed to Step 8.14.
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Federal Register / Vol. 55, No. 61 / Thursday, March 29, 1990 / Rules and Regulations 11873
8.13.2 If compatible (e.g., multiple phases
will riot result on combination), combine the
filtered liquid resulting from Step 8.12 with
the initial liquid phase of the waste obtained
inStep 8.7, This combined liquid is defined as
the TCLP extract Proceed, to Step 8.14.
8.13.3 If the initial liquid phase of this
waste, as obtained from Step 8.7, is not or
may not be compatible with the filtered liquid
resulting from Step 842, dp not combine these
liquids/Analyze these liquids, collectively
defined as the TCLP extract, and combine the
.results mathematically, as described in Step
8.14.
8.14 Following collection of the TCLP
extract, the.pH of the extract should be
recorded. Immediately aliquot and preserve
the extract for analysis. Metals aliquots must
be acidified with Citric acid to pH<2. If
precipitation is observed upon addition of
nitric acid to a small aliquot of the extract;
then the remaining portion of the extract for
metals analyses shall not be acidified and the
extract shall be analyzed as soon as possible.
All other aliquots must be stored under ,
refrigeration (4 °C] until analyzed. The TCLP
extract shall be prepared and analyzed
according to appropriate analytical methods.
TCLP extracts to be analyzed for metals shal
be acid digested except in those instances
where digestion causes loss of metallic.'
contaminants, If an analysis of the
undigested extract shows that the
concentration of any regulated metallic
contaminant exceeds the regulatory level,
then the waste is hazardous and digestion of
the extract is not necessary. However, data
on undigested extracts alone cannot be used
to demonstrate that the waste'is not
hazardous. If the individual phases are to be
analyzed separately, determine the volume of
the individual phases (to +0.5 percent),
conduct the appropriate analyses, and
combine the results' mathematically by using
a simple volume-weighted average:
Final analyte Concentration = -
(V.)(Ci)+(V:0(CO
V,+V2
where:
Vi ='The volume of the first phase (L).
Ci=The concentration of the contaminant of
concern in the first phase (mg/L). ,
ya=The volume of the second phase (L). ,
Cz=The concentration of the contaminant of
concern in the second phase (mg/L).
. 8.15 Compare the contaminant
concentrations in-the TCLP.extract'With the
thresholds identified in the appropriate
regulations. Refer to § 10.0 for .quality
assurance requirements.
9.0 Procedure When Volatiles Are Involved
Use the ZHE device to obtain TCLP extract
for analysis of volatile compounds only.
' Extract resulting from the "use of the ZHE
shall not'be used to evaluate the mobility of
nonvolatile analytes (e.g.; metals, pesticides,
etc.);
• The ZHE device has approximately a 500-
mL internal capacity. The ZHE can thus
accommodate a maximum of 25 grams of
solid (defined as that fraction of a sample
from which no additional liquid may be
forced out by an applied pressure of 50 psi),
due to the need to add an amount of
extraction fluid equal to 20 times the weight
. of the 'solid phase.
Charge .the ZHE with sample only once and
do not open the device until the final extract
. (of the solid) has been collected. Repeated
filling of the ZHE to obtain 25 grams of solid
is not permitted.
Do not allow the waste, the initial liquid "
phase, or the extract to be exposed to the
atmosphere for any more time than is
absolutely necessary. Any manipulation of '
these materials should be done when cold (4
°C) to minimize loss of volatiles. .
9.1 Pre-weigh the (evacuated), filtrate
collection container (See Step 4.6) and set
aside. If using a TEDLAR" bag, express all
liquid from the ZHE device into the bag,
whether for the initial or final liquid/solid
separation, and take an aliquot from the' •
liquid in the bag for analysis. The containers
listed in Step 4.6 are recommended for use
under the conditions stated in 4.6.1-4.6,3.
9.2 Place the ZHE piston within the body.
of the ZHE (it may be helpful first to moisten
the piston O-rings slightly with extraction'
fluid). Adjust the piston within the ZHE body
to a height that will minimize the distance .the
piston will have to move once the ZHE. is
charged with sample (based upon sample size
requirements determined from Section 9.0,
Step 7.1 and/or 7.2). Secure the gas inlet/
outlet flange, (bottom flange) onto the ZHE
body in accordance with the manufacturer's
instructions. Secure the glass fiber filter
between the support screens and set aside.
Set liquid inlet/outlet flange (top flange)
aside. . '
9.3 If the waste is 100 percent solid (see
.Step 7.1), weigh out a subsample (25 gram.
maximum) of the waste, record weight, and
proceed to Step 9.5.
9A If the waste contains <0.5 percent dry
solids (Step 7.2), the liquid portion of waste,
after, filtration, is defined as .the TCLP
extract Filter enough of the sample so that
the amount of filtered liquid will support all
of the volatile analyses required. For wastes
containing >0.5 percent dry solids (Steps 7.1
and/or 7.2), use the percent solids
.information obtained in Step 7.1 to determine
the optimum sample size to charge into the
. ZHE. The recommended sample size is as
follows: '
9,4.1 For wastes containing '< 0.5 percent
solids, (see Step 7,1), weigh out a 500-gram
subsample of waste and record the weight.
9.4.2 For wastes containing > 0.5 percent
solids (see Step 7.1), determine the amount of
waste to charge into the ZHE as follows:
Weight of waste to change ZHE — -
25
Percent solids (Step 7.1)~
X100
Weigh out a subsample of the waste of the
, appropriate size arid record the weight.
• 9.5 if particle-size reduction of the solid
portion, of the waste was required in Step 7.3,
proceed to Step 9.6. If particle-size reduction
was not required in Step 7.3, proceed to Step
3.7.
9.8 Prepare the .waste for extraction by
crushing, cutting, or grinding the. solid portion
6f the waste 'to a. surf ace area or particle-size
as described in Step 7.3.1. Wastes and ,
appropriate reduction equipment should be
refrigerated, if possible, to 4 "Cfprior to
particle-size reduction. The means used to
effect particle-size'reduction must not
generate heat in and of itself. If reduction of'
the solid phase of .the waste is necessary,
exposure of the waste to the atmosphere
should be avoided to the extent possible.
Note: Sieving of the waste is not '
recommended due to the possibility that
volatiles may be lost. The use of an
appropriately graduated ruler is .
recommended as an acceptable alternative. •
Surface area- requirements are meant for
filamentous (e.g., paper, cloth) and similar
waste materials. Actual measurement of
surface area is not recommended.
When the surface area or particle-size has
been appropriately altered, proceed to Step
9.7.
9.7 'Waste slurries need not be allowed to
stand to permit the solid phase to settle. Do
not centrifuge wastes prior to filtration.
" 9,8 Quantitatively transfer the entire
sample (liquid and solid phases) quickly to
the ZHE. Secure the filter and support '
screens onto the top flange of the device and
secure the top flange to the ZHE body in
accordance with the manufacturer's
instructions. Tighten all ZHE fittings and.
place the device in the vertical position (gas
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11874 Federal Register / Vol. 55; No. 61 /Thursday, March 29, 1990 / Rules and Regulations
inlcl/outtei flange on the bottom). D.o not
attach the extract collection device to the top
plate.
Note: If waste material (>1% of original
sample weight) has obviously adhered to the ,
container used to transfer the sample to the
Zi IE, determine the weight of this residue
and subtract it from the sample weight
determined in Step 9.4 to determine the
weight of the waste sample that will be
filtered.
Attach 11 gas line to the gas inlet/outlet
valve (bottom flange) and, with the liquid
tnlct/oullet valve (top flange) open, begin •
applying gentle pressure of 1-10 psi (or more
if necessary) to force all headspace slowly
out of the ZHE device into a hood. At the first
appearance of liquid from the liquid inlet/
outlet valve, quickly close the valve and
discontinue pressure. If filtration of the waste
at 4 "C reduces the amount of expressed
liquid over what would be expressed at room
temperature, then allow the sample to warm
up to room temperature in the device before
filtering.' If the waste is 100 percent solid (see
Step 7.1), slowly increase the pressure to a
maximum of 50 psi to force most of the
headspace out of the device and proceed to
Step 9.12;
9.9 Attach the evacuated pre-weighed
filtrate collection'container to the liquid
inlet/outlet valve and open the valve. Begin
applying gentle pressure of 1-10 psi to force
the liquid phase of the sample into the filtrate
collection container. If no additional liquid
has passed through the filter in any 2-minute
interval, slowly increase the pressure in 10-
pai increments to a maximum of 50 psi. After
each incremental increase of 10 psi, if no
additional liquid has passed through the filter
in any 2-minute interval, proceed to the next
10-psi increment. When liquid flow has
ceased such that continued pressure filtration
at 50 psi does not result in any additional
filtrate within a 2-minute period, stop the
filtration. Close the liquid inlet/outlet valve,
discontinue pressure to the piston, and
disconnect and weigh the filtrate collection
container.
Note: Instantaneou s application, of high.
pressure can degrade the glass fiber filter and
may cause premature plugging.
9.iO The material in the ZHE is defined as
the solid phase .of the waste and the filtrate is
defined as.the liquid phase.
Note: Some wastes, such as oily wastes
and some paint wastes, will obviously
contain some material that appears to be a
liquid. Even' after applying pressure filtration:
this material will not filter. If this is the case,
the material within the filtration device is
defined as a solid and is carried through the
TCLP extraction as a solid.
If the original waste contained <0,5 \
percent dry solids (see Step 7.2), this filtrate
is defined as the TCLP extract and is
analyzed directly. Proceed to Step 9.15.
9.11 The liquid phase may now be either
analyzed immediately (See Steps 9.13 through
9.15) or stored at 4 °C under minimal
headspace conditions: until time of analysis.
Determine the weight of extraction fluid #1 to
add to the ZHE as follows:
Weight of extraction fluid = •
20Xpercent solids (Step 7.1) X weight of waste filtered (Step 9.4 or :B.O)
100
0,12 The following steps detail how to
add tho appropriate amount of extraction
fluid to the solid material within the ZHE and
agitation of the ZHE vessel. Extraction fluid
£1 is used in all cases (See Step 5.6).
9.12.1 With the ZHE in the vertical
position, attach a lina from the extraction
fluid reservoir to the liquid Inlet/outlet valve.
Tho lino used shall contain fresh extraction
fluid and should be preflushed with fluid to
eliminate any air pockets-in the line. Release
gas pressure on the ZHE piston (from the gas
inlot/oullet valve), open the liquid inlet/.
outlet valve, and begin transferring extraction
fluid (by pumping or similar means) into the
Zt IE. Continue pumping extraction fluid into
the ZHE until tho appropriate amount of fluid
JIBS boon introduced into the device.
0=12,2 After the extraction fluid has been
added, Immediately close the liquid inlet/
outlet valve and disconnect the extraction
fluid line. Check the ZHE to ensure that all
valves mre In their closed positions. Manually
rotate the device in an end-over-end fashion
2 or 3 times. Reposition the ZHE in the
vertical position with the liquid inlet/outlet
Valve on top. Pressurize the ZHE to 5-10 psi
(If necessary) and slowly open the liquid
inlet/outlet valve to bleed out any headspace
(Into a hood) that may have been'introduced
due to the addition of extraction fluid. This
bleeding shall be done quickly and shall be
stopped at the first appearance of liquid from
the valve. Re-pressurize the ZHE with 5-10
psi and check all ZHE fittings to ensure that
'they are closed.
9.12.3 Place the ZHE in the rotary
agitation apparatus (if it is not already there)
and rotate at 30+2 rpm tot 18+2 hours.
Ambient temperature (i.e., temperature of
room in which extraction occurs) shall be
maintained at 22+3 °C during agitation. •
9.1,3 Following the 18 +2 hour agitation
period, check the pressure behind the ZHE
piston by quickly opening and closing the gas
inlet/outlet valve and noting the escape of
gas. If the pressure has not been maintained
(i.e., no gas release observed), the device is
leaking. Check the .ZHE for leaking as
specified in Step 4.2.1, and perform the
extraction again with a new sample of waste.
If the pressure within the device has been
maintained, the material in the extractor.
vessel is once again separated into its
component liquid and solid phases. If the
waste contained an initial liquid phase, the
liquid may be filtered directly into the same
filtrate collection container (i.e., TEDLAR8
.bag) holding the initial liquid phase of the
waste. A separate filtrate collection container
must be used if combining would create
multiple phases, or there is not enough
volume left within the filtrate collection
container. Filter through the glass fiber filter,
•using the ZHE device as discussed in Step
9.9. All extract shall be filtered and collected
if the TEDLAR? bag Is used, if the extract is
multiphaslc, or if the waste contained an
initial liquid phase (sse Steps 4.6 and 9.1).
Note: An in-line glass fiber filter may be
used to filter the material within the ZHE if it"
is suspected that the glass fiber filter has •
been ruptured. .
9.14 If the original waste contained no
initial liquid phase, the filtered liquid ,
material obtained from step 9.13 is defined as
the TCLP extract. If the waste contained an
initial liquid phase, the filtered liquid
material obtained from Step 9.13 and the
initial liquid phase (Step 9.9} are collectively
defined as the TCLP extract.
9.15 Following collection of the TCLP
extract, immediately prepare the extract for
analysis and store with minimal headspace at
4 °C until analyzed; /uialyze the TCLP extract
according to the appropriate analytical •
methods. If the individual phases are to be
analyzed separately |i..e., are not miscible),
determine the volume of the individual
phases (to 0.5%), conduct the appropriate ,
analyses, and combine the results
mathematically by using a simple volume-
weighted average: :
Final analyte concentration •
(V.) (C.)+'(V»)
Vi+V,
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Federal Register / Vol. 55. No. 61 / Thursday, March 29. 1990 / Rules and Regulations
where:
Vi =The volume of the first phases (1).
' Ci =The concentration of the contaminant of
. concern in the first phase (mg/1).
Vs.—The volume of the second phase (1).
Cj=The concentration of the contaminant of
concern in the second phase (mg/1).
9.16 Compare the contaminant
•concentrations in the TCLP extract with the
thresholds identified in the appropriate
regulations. Refer to section 10,0 for quality
assurance requirements.
10.0 Quality Assurance Requirements
10.1 Maintain all data, including quality
assurance data, and keep it available for
reference or inspection.
1012' 'Aminimum 'of one blank (extraction
fluid#1) for every 10 extractions that have
been conducted in an'extraction vessel shall
be employed as a check to determine if any
' memory effects from the extraction
equipment are occurring.
10.3 • A matrix spike shall be performed for
each waste unless the result exceeds the
regulatory level and the data is being used
solely to demonstrate that the waste property
exceeds the regulatory level. If more than one
• sample of the same waste is being tested, a
matrix spike needs to be performed for every
twenty samples and the average percent
recovery applied to the waste
characterization.
10.3.1 Matrix spikes are to be added after
filtration of Ihe TCLP extract and before
preservation. Matrix spikes should not be
added prior to TCLP extraction of the sample.
10.3.2 Matrix spike levels should be made
at the appropriate regulatory threshold limits.
However, if .the extract contaminant
concentration is less than one half the
threshold limit, the spike level may be one
half the contaminant concentration but hot
less than the quantitation limit or a fifth of
.the threshold limit.
10.3.3 The purpose of the matrix spike is
to monitor the adequacy of the analytical
methods used on the TCLP extract and to
determine whether matrix interferences exist
In analyte detection. If the matrix spike
recoveries are less than 50%, then .the
analytical methods are not performing
adequately or use of the methods is
inadequate. Use of internal calibration
quantitation methods, modification of the
analytical methods, or use of alternate
analytical methods may be needed to
accurately measure the contaminant
concentration in the TCLP extract.
: 10.3.4 Use of internal quantitation
methods is also required when the
contaminant concentration is within 20% of
the regulatory level. (See section 10,5
concerning the use of internal calibration
methods.)
10.3.5 Matrix spike recoveries are
calculated by the following formula:
A-B
Percent recovery = • X 100%
where A—the concentration of the spiked
sample,
B=the concentration of the unspiked
sample, and
C=the spike level
10.4 All quality control measures
described in the appropriate analytical
methods shall be followed.
10.5 . The use of internal calibration
quantitation methods shall be employed for a
contaminant if: (1) Recovery of the
contaminant, from the TCLP extract is not at
least 50% and the concentration does not
exceed the regulatory level, and (2) The
concentration of the contaminant measured
in the extract is within 20% of the appropriate
regulatory level.
10.5.1 The method of standard additions
shall be employed as the internal calibration
SAMPLE MAXIMUM HOLDING TIMES
[Days!
quantitation method for each metallic
contaminant.
.10.5.1.1 The method of standard additions
requires preparing calibration standards lit
the sample matrix rather than reagent water
or blank solution. It requires taking four
identical aliquots of the solution and'adding
known amounts of standard to three of these
aliquots. The fourth aliquot is the unknown.
Preferably, the first addition:should be
prepared so that the resulting concentration
is approximately 50% of the expected
concentration, of the sample. The second and
third additions should be prepared so that the
concentrations are approximately 100% and
150% of the expected concentration of the
sample. All four aliguots are maintained at •
'•the same final volume by adding reagent
water or a blank, solution, and may need
dilution adjustment to maintain the signals in
the linear range of the instrumental
technique. All four aliquots are analyzed.
10.5.1.2 Prepare a plot, or subject data, to
linear regression, of instrumental signals or
external-calibration-derived concentrations
as the dependent variable (y-axis) versus
concentrations of the additions of standard
as the independent variable (x-axis). Solve
for the- intercept of the abscissa (the
independent variable, x-axis) which is the
concentration in the unknown.
10.5.1.3 Alternately, subtract the
instrumental signal or external-calibration- .
derived concentration of the unknown
(unspiked) sample from the instrumental
signals or external-calibration-derived
concentrations of the standard additions. Plot
or subject data to linear regression of the
corrected instrumental signals or external-
calibration-derived concentrations as the
dependent variable versus the independent
variable. Derive concentrations for unknowns
using the internal calibration curve as if it
were an external calibration curve.
10-.8 Samples must undergo TCLP
extraction within the following time periods:
Volatiles
Semi-volafiles .„ ..
Mercury :.._.. . • ' '
Metals, except mercury.!..... i.;
From:
Reid collection
To:
TCLP extraction
14
7
28
180
From:
TCLP extraction
To:
Preparative extraction
NA
7
NA
'NA
From:
Preparative extraction
To:
Determinative analysis
14
40
28
180
Total elapsed time
28
54
56
330
Not applicable.
If sample holding times are exceeded, the
values obtained will be considered minimal
concentrations. Exceeding the holding time, is
hot acceptable in establishing that a waste
does not exceed the regulatory level.
Exceeding the holding time will not
invalidate characterization if the was.te
exceeds the regulatory level.
PART 264—STANDARDS FOR
OWNERS AND OPERATORS OF
HAZARDOUS WASTE TREATMENT,
STORAGE, AND DISPOSAL
FACILITIES
7. The authority citation for part 264
continues to read as follows:
Authority: 42 U.S.C. 6905, 6912, 6924, and
6925.
8. Section 264.301 is amended by
revising paragraph (e)(l) to read as
follows:
§ 264.301 Design and operating
requirements.
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11876 Federal Register / Vol. 55* No. 61 /Thursday, March 29, 1990 / Rules and Regulations
M " «
(1) The monofill contains only
hazardous wastes from foundry furnace
emission controls or metal casting
molding sand, and such wastes do not
contain constituents which would
render the wastes hazardous for reasons
other than the Toxicity Characteristic in
§ 261.24 of this chapter, with EPA
Hazardous Waste Numbers D004
through D017; and
PART 2S5—INTERIM STATUS
STANDARDS FOR OWNERS AND
OPERATORS OF HAZARDOUS .WASTE
TREATMENT STORAGE, AND
DISPOSAL FACILITIES
9. The authority citation of part 265
continues to read as follows:
Authority: 42 U.S.C. 6905.6912(a), 6924,
0335. and 0935.
10. Section 265.221 is amended by
revising paragraph (d)(l) to read as
follows:
§ 265.221 Design requirements.
* * * * *
(d) • • *
(1) The monofill contains only
hazardous wastes from foundry furnace
emission controls or metal casting
molding sand, and such wastes do not
contain constituents which would
render the wastes hazardous for reasons
other than the Toxicity Characteristic in
§ 261.24 of this chapter, with EPA
Hazardous Waste Numbers D004
through D017; and
*****
11. Section 265.273 is amended by
revising paragraph (a] to read as
follows:
§ 265.273 Waste analysis.
*****
(a) Determine the concentrations in
the waste of any substances which.
equal or exceed the maximum
concentrations contained in Table 1 of
§ 261.24 of this chapter that cause a
waste to exhibit the Toxicity
Characteristic;
PART 268—LAND DISPOSAL
RESTRICTIONS
12. The authority citation for part 268
continues to read as follows:
Authority: 42 U.S.C. 6905,6912(a), 6921. and
6924.
13. Appendix I of part 268 is revised to
read as follows:
Appendix I—Toxidty Characteristic
Leaching Procedure (TCLP)
Note: The TCLP is published in Appendix II
of part 261.
PART 271— REQUIREMENTS FOR
AUTHORIZATION OF STATE
HAZARDOUS WASTE PROGRAMS
14. The authority citation for part 271
. continues to read as follows:
Authority: 42 U.S.C. 6905,6912(a), and 6926.
15. Section 271.1, paragraph (j), the
' heading of Table 1 is republished, and
Table 1 is amended by adding the
following entry in chronological order
by date of promulgation to read as
follows:
§ 271.1 Purpose and scop®.
* * * * *
(D* * *
TABLE 1.—REGULATIONS IMPLEMENTING THE HAZARDOUS AND SOLID WASTE AMENDMENTS OF 1984
Promulgation date
Title of regulation
Federal Register reference
Effective date
March 29,1990.
Toxicity characteristic..
[Insert FR reference on date of publU September 25,1990
cation}.
PART 302—DESIGNATION,
REPORTABLE QUANTITIES, AND
NOTIFICATION
16. The authority citation for part 302
continues to read as follows:
Authority: 42 U.S.C. 960% 33 U.S.C. 1321
and 1361.
17. Section 302.4 is amended by
revising under the column Hazardous
Substance the entry "Unlisted
Hazardous Wastes Characteristic of EP
Toxicity" to read "Unlisted Hazardous
Wastes Characteristics:" and by
revising the entry "Characteristic of EP
Toxicity" and its siub entries to read as
follows:
§ 302.4 Designation of hazardous
substances.
TABLE 302.4.—LIST OF HAZARDOUS SUBSTANCES AND REPORTABLE QUANTITIES
Hazardous substance
CASRN
Regulatory synonyms
RQ
Statutory
Final RQ
Codet
RCRA
waste
number
Category Pounds (Kg)
Characteristic of Toxidty:
Arsonte (0004) ....„_.._.„._ ._»_.„_ NJV.
Barium (0005}......... ~. NA
Benzene (D018)............,......-—............ N.A.
Cadmium (O006) NA
Carbon tetrachtoride (0019) NA
Chtofdana (O020) . ....„ NA
CntorobanMM (0021) NA
Chteroterm (D022)~__-^_—_ NA
Chromium (0007) ~~ NA
oOoioi (0023) _.™™™™._.™ _. NA
nvCr««rf (0024) NA
•1
•1
1000
•1
5,000
1
1.00
5,000
M
1,000
1,000
4
4
1.2,3,4
4
1.2,4
1. 2, 4
1,2,4
1,2,4
4
1,4
1.4
0004
D005
D018
0006
D019
D020
D021
D022
D007
0023
D024
X
c
A
A
A
X
B
A
A
C
C
1 (0.454)
1,000 (454)
10 (4.54)
10 (4.54)
10 (4.54)
1 (0.454)
100 (45.4)
10 (4.54)
10 (4.54)
1,000 (454)
1,000 (454)
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Federal Register / Vol. 55, No. 61 / Thursday, March 29, 1990 / Rules and Regulations 11877
TABLE 302.4.—LIST OF HAZARDOUS SUBSTANCES AND REPORTABLE QUANTITIES—Continued
Hazardous substance
p-Cresol (D025) j •
Gresol (D026)
2,4-0 (D016) '
1,4-Dichlorobenzene (D027)
1,2-Dichloroethane (D028)
1,1-Dichloroethylene (D029)
2,4-Dinitrotoluene (D030)
Endrin (D012)
Heptachlor (and hydroxide) (D031)
Hexachlorobenzeno (D032)......
Hexachlorobutadiene (D033)
Hexachloroethane (D034)
Lead (D008)
Lindane (D013) :.
Mercury (D009) .•
Methoxychlor (D014)
Methyl ethyl ketone (D035).._ :
Nitrobenzene (D036)
Pentachlorophenol (D037)
Pyridine (O038)
Selenium (D010)..., ,
Silver (D011).. : „...; . .
Tetrachloroethylene (D039)
Toxaphene (D015)
Thrichloroethylene (D040)
2,4,5-Trichloroethylene (D041)
2,4,6-Trichlorophenol (0042)
2,4,5-TP (D017)
Vinyl chloride (D043)
» ' *
CASRN Regulatory synonyms
N.A.
N.A.
N.A.
N.A
N.A. ;.. ..
NA
N,A.
NA
N.A.
NA
N.A.
N.A.
N.A. „
NA .. .
N.A.
N.A.
N.A
N.A.
N.A.
NA
NA
NA
N A. ,
N.A. ;
N.A.
N.A.
N.A.
NA. ..
NA.
* * *
RQ
1 000
1 000
100
100
5,000
5000
1 000
1
1
*
*
.
•
•1
1
-*1
1 000
10
«1
«•)
••)
•1
1
1000
io
10
100
*i
Statutory
Codet
1 4
1 4
1 4
124
1,2,4
124
1, 2,4
1 4
1, 2,4
2 4
2 4
2,4
4
1, 4
4
1 4
4
124
1, 2, 4
4
4
4
2 4
1 4
124
' 1 4
124
1 4
234
*
RCRA
waste
number
D025
D026
D016
D027
D028
D029
D030
0012
D031
D032
D033
D034
D008
D013
D009
D014
D035
D036
D037
D038
D010
D011
D039
D015
D040
D041
D042
D017
D043
*
Fir
Category
c
c
B
B
B
B
A
X
X
A
X
B
X
X
X
D
c
A
c
A
X
B
X
B
A
A
B
X
mlRQ
Pounds (Kg)
1,000 (454)
1,000 (454)
100 (45.4)
100 (454)
100 (45.4)
100 (454)
10 (4.54)
1 (0454)
1 (0.454)
10 (454)
1 (0454)
100 (454)
(#)
1 (0.454)
1 (0454)
•t (0454)
5000 (2270)
1,000 (454)
10 (4.54)
1 000 (454)
10 (4 54)
1 (0454)
100 (454)
1 (0454)
100 (454)
10 (454)
10 (4.54)
100 (454)
1 (0454)
*
t—indicates the statutory source as defined by 1,2, 3, or 4 below.
*«—indicates that the 1-pound RQ is a CERCLA statutory RQ.
#—indicates that the RQ is subject to change when the assessment of potential carcinogenicity is completed.
[FR Doc. 90-6104 Filed 3-28-90; 8:45 am]
BILLING CODE 6560-50-M
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