Thursday
December 21, 1995
Part II
Environmental
Protection Agency
40 CFR Parts 260, 261, 266, and 268
Hazardous Waste: Identification and
Listing; Proposed Rule
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66344 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Parts 260, 261,266, and 268
[FRL-5337-9]
BIN 2050-AE07
Hazardous Waste Management
System: Identification and Listing of
Hazardous Waste: Hazardous Waste
Identification Rule (HWIR)
AGENCY: Environmental Protection
Agency.
ACTION: Proposed rule, tentative
response to Chemical Manufacturers
Association petition and the Hazardous
Waste Identification Dialogue
Committee recommendations, and
request for comments.
SUMMARY: The Environmental Protection
Agency (EPA) today is proposing to
amend its regulations under the
Resource Conservation and Recovery
Act (RCRA) by establishing constituent-
specific exit levels for low-risk solid
wastes that are designated as hazardous
because they are listed, or have been
mixed with, derived from, or contain
listed hazardous wastes. Under this
proposal, generators of listed hazardous
wastes that meet the self-implementing
exit levels would no longer be subject to
the hazardous waste management
system under Subtitle C of RCRA as
listed hazardous wastes. Today's Notice,
commonly referred to as the Hazardous
Waste Identification Rule (HWIR),
establishes a risk-based "floor" to
hazardous waste listings that will
encourage pollution prevention, waste
minimization, and the development of
innovative waste treatment
technologies.
Many of the exit levels are established
using an innovative risk assessment
which evaluates potential exposure
pathways, both direct and indirect, from
a variety of sources, such as waste piles
and surface impoundments. This
assessment focuses on both human and
environmental receptors and is
presented for comment in today's
Notice. The remaining exit levels are
based on an alternative risk analysis.
The Agency is also proposing to
modify some of the land disposal
restriction (LDR) numerical treatment
standards listed in subpart D of 40 CFR
part 268. This notice proposes to cap
technology-based treatment standards
with the risk-based exit levels which
minimize threats to human health and
the environment. This notice also takes
comment on several general approaches
and one specific approach for
conditional exemptions from subtitle C
management. Today's notice also
contains the Agency's tentative response
to a petition for rulemaking submitted
by the Chemical Manufacturers
Association and the Agency's tentative
response to the recommendations made
by the Dialogue Committee on
Hazardous Waste Identification. This
committee was formally chartered in
July 1993 in accordance with the
Federal Advisory Committee Act
(FACA).
DATES: EPA will accept public
comments on this proposed rule until
February 20,1996. Comments
postmarked after this date may not be
considered. However, the Agency
recognizes that, because of the
complexity of this proposed rulemaking,
some commenters may want to request
additional! time for comment submittal.
In anticipation of these requests, EPA
will be communicating with the
litigants .and the court regarding the
implications on our rulemaking
schedule of a possible extension of the
comment period for this proposal. If the
comment period is extended, the
Agency will provide notice of such in
the Federal Register.
Any person may request a public
hearing on this amendment by filing a
request with Mr. David Bussard, whose
address appears below, by January 5,
1996.
ADDRESSES: The public must send an
original, two copies, and whenever
possible, a 3.5 inch computer disk
containing the comments in a common
word processing format such as
WordPerfect version 5.1'. to: EPA RCRA
Docket (5305W), 401 M Street, SW.,
Washington, DC 20460.
Place "Docket number F-95-WHWP-
FFFFF" on your comments. The RCRA
docket is located at: EPA's Crystal
Gateway Office, 1235 Jefferson Davis
Highway, Arlington, Virginia, and is
open from 9 a.m. to 4 p.m., Monday
through Friday, excluding Federal
holidays. The public must make an
appointment to review docket materials
by calling (703) 603-9230. The public .
may copy material from any regulatory
docket at a cost of $0.15 per page.
Copies of the background documents,
Integrated Risk Information System
(IRIS) chemical files, and other
references (which are not readily
available) are available for viewing and
copying only in the RCRA docket.
Requests for a public hearing should
be addressed to Mr. David Bussard,
Director, Characterization and
1 This will greatly facilitate EPA's preparation of
the comment responses and will significantly
reduce the cost associated with responding to the
comments.
Assessment Division, Office of Solid
Waste (OS-330), U.S. Environmental
Protection Agency, 401 M Street, SW.,
Washington, DC 20460.
FOR FURTHER INFORMATION CONTACT: The
RCRA/Superfund Hotline at (800) 424-
9346 or at (703) 412-9810. For technical
information contact Mr. William A.
Collins, Jr., Mr. Greg Helms, or Ms.
Pamela McMains, Office of Solid Waste
(5304), U.S. Environmental Protection
Agency, 401 M Street, S.W.,
Washington, DC 20460, (202) 260-4770.
Preamble Outline
I. Authority
II. Background
A. Overview of Hazardous Waste
Identification Program
B. The Mixture and Derived-From Rules
and the Contained-In Policy
C. Overview of Expected Impacts of the
Exit Rule
III. Scope of Revisions to the Mixture and
Derived-From Rules
A. Rationale for Retention of the Mixture
and Derived-From Rules
B. Revision to Derived-from Rule for
Wastes Listed Because They Exhibit the
Characteristics of Ignitability,
Corrosivity, or Reactivity
IV. Development of Exit Levels and Minimize
Threat Levels
A. Need for an Exit
B. Overview of the Exit
C. Selection of Constituents of Concern
1. Development of the Master List
2. Development of the Exit Constituent List
3. Constituents of Ecological Concern ,
D. Risk-Based Information
1. Human Health Benchmarks
a. Non-carcinogens
b. Carcinogens
c. Consideration of MCLs
2. Ecological Benchmarks
3. Sources of Data
a. Human
b. Ecological
E. Risk Assessment
1. The Risk Analysis
a. Introduction
b. How the Analysis was Structured
c. How Uncertainty is Addressed
d. Linkage of the Risk Analysis to the
Groundwater Fate and Transport
e. Risk Targets Used
2. Detailed Overview of the Non-
Groundwater Risk Analysis
a. Waste Management Units
1. Use of Subtitle D Survey
2. Fate and Transport
3. Ash Monofill
i. Particle Size Distribution for Air
Dispersion Modeling
ii. Monofill Characterization
iii. Vehicle Traffic
iv. Emission Equations for Ash Blown from
Trucks and Spreading and Compacting
4. Land Application Unit
i. Particle Size Distribution for Air
Dispersion Modeling
ii. Area of Land Application Unit Relative
to Agricultural Field
iii. Application Rate
iv. Waste Characteristics
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Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66345
v. Depth of Contamination
vl. Partitioning
5. Waste Pile
1. Waste Pile Height
11. Particle Size Distribution for Air
Dispersion Modeling
ill. Waste Characteristics
lv. Vehicle Traffic
v. Emission Equation for Ash Blown from
Trucks
6. Surface Impoundments
1. Two-Phase Sludge Formation Model
11, Dilution of Waste During a Spill
7. Tank
1. Unit Characterization
il. Volatilization
8. Combustors
b. Fate and Transport
1. Pathways
2. Equations
3. Specific Issues on Pathways and
Equations
1. Chemical Transformation
H. Biodegradation
Hi. Meteorological Data
iv. Soil Data
v. Soil Pathways
vl. Surface Water Pathways
vil. Food-Chain Pathways
c, Receptors
1. Human Receptors
2. Ecological Receptors
3. Groundwater Fate and Transport
Modeling
a. Fate and Transport Processes
1. Effects of groundwater mounding
2. Transformation products
3. Fate and transport of metals
b. Enhanced solution algorithms
1. Linkage between unsaturated zone and
saturated zone modules
2. Numerical transport solution
3. Solution for metals transport
4. Elimination of biases in determination of
receptor well concentrations
c. Revision of Monte Carlo methodology for
nationwide assessments
1. Data sources
2. Finite-source methodology
3. Site-based regional analysis
d. Implementation of EPACMTP
e. Waste management scenarios
1. Landfills
2, Surface impoundments
3. Waste piles
4. Land application units
f. Determination of regulatory limits
g. Chemical specific fate and transport
processes
1. Organic constituents
2. Motals
4. Other Risk Assessment Issues
a. Difference between groundwater and
nongroundwater pathways
1. Infiltration
2. Density of waste applied to land
application unit
3. Unsaturated zone characteristics
4. Hydrolysis rates
b. Other groundwater pathway analysis
issues
1. Use of 1000 years versus 10,000 years
exposure time horizon
2. Implementation of parameter bounds in
Monte Carlo procedure
3. Hydraulic conductivity of surface
impoundment bottom layer
4. Waste pile infiltration rates
5. Land application unit infiltration rates
6. Aggregate effects of alternative
groundwater modeling procedures
F. Additional Eco-Receptor Consideration
G. Background Concentrations in Soils and
other Issues Relating to Results
H. Constituents with Extrapolated Risk-
based Levels
I. Analytical Considerations
1. Development of Exemption Quantitation
Criteria (EQC)
2. EQCs and LDR Requirements as
Exemption Criteria
a. EQCs as exit levels
b. LDR Requirements in combination with
EQC Exit Levels
3. Exemption for Constituents Without
EQCs
V. Presentation of Exit Levels
A. Constituents with Modeled or
Extrapolated Risk-based Exit Levels
B. Constituents with Quantitation-based
Exit Levels
C. How to Read the Exit Level Tables
VI. Minimize Threat Levels
A. Background
1. Summary of the Hazardous and Solid
Waste Amendments of 1984
2. EPA's Interpretation of Standard for
Treatment Requirements
B. Risk Assessment and Minimize Threat
Levels
1. Rationale
2. Public Policy Considerations
C. Minimize threat levels
1. List of Constituents and Minimize
Threat Concentrations
2. Constituents for which Exit Levels are
not Minimize Threat Levels
D. Meeting LDR requirements
1. Wastes Below Exit Levels as Generated
2. Wastes Above Exit Levels as Generated
VH. Dilution
VIII. Implementation of Exit
A. Implementation Requirements
1. Testing Requirements
a. Data Evaluation
i. Compliance with the Exit Levels
ii. Wastewater and Nonwastewater
Categories
iii. Totals and TCLP Analyses
iv. Oily Wastes
b. Initial Test
2. Notification Requirements
B. Implementation Conditions
1. Records Maintained on Site
2. Testing Conditions
3. Testing Frequency and Process Change
C. Public Participation
IX. Request for Comment on Options for
Conditional Exemptions
A. Legal Basis for Conditional Exemptions
B. Improvements in Management of Non-
Hazardous Waste and in Risk
Assessment Methodology
C. Overview of Options for Conditional
Exemptions
1. National Approach
a. Eliminate Disposal in Land Application
Units
b. Unit-Specific Exit Levels for Each
Disposal
c. Consideration of Additional
Management Unit Design or Management
Practices
2. State Program Approach
3. Establish Exit Levels that Consider
Regional or Site-Specific Factors that
might Affect Constituent Fate and
Transport
4. Relief from Land Disposal Restrictions
D. Land Disposal Restrictions for
Contingent Management Options
E. Contingent Management of Mixed Waste
X. Implementation of Conditional Exemption
Option 1
A. Introduction and Overview
B. When Contingent Management
Exemptions Become Effective
1. Placement of the waste in a qualifying
unit
2. Point of generation
C. Requirements for Obtaining an
Exemption
1. Sampling and Testing Requirements for
Contingent Management Exemptions
2. Requirements for Public Participation in
contingent Management Exemptions
3. Notification Requirements for
Contingent Management
D. Implementation Conditions
1. Tracking conditions
2. Qualifying Unit
3. Claimant's Duty to Ensure Compliance
with all Conditions
E. Retesting and Recordkeeping Conditions
for Contingent Management Exemptions
F. Compliance Monitoring and
Enforcement for Contingent Management
Exemptions
1. Compliance Monitoring
2. Enforcement
G. Exports of Wastes Eligible for
Contingent Management Exemptions
H. Land Disposal Restrictions
XI. Relationship to Other RCRA Regulatory
Programs
A. Hazardous Waste Determination
B. Characteristic Hazardous Waste
C. Toxicity Characteristic Level for Lead
D. Hazardous Waste Listings
E. Delisting
F. Requirements for Treatment, Storage,
and Disposal Facilities and Interim
Status Facilities
G. Closure
H. HWIR-Media Rule/Subtitle C Corrective
Action
I. Land Disposal Restriction Program
J. RCRA Air Emission Standards
K. Hazardous Debris
L. Hazardous Wastes Used in a Manner
Constituting Disposal
XII. CERCLA Impact
XIII. State Authority
A. Applicability of Rules in Authorized
States
B. Effect of State Authorizations
C. Streamlining Issues
XIV. Regulatory Requirements
XV. References
Appendix A: Background Tables for Risk
Analysis Receptors and Pathways
Appendix B: Table Comparing Groundwater
Modeling Effects of 1000 vs. 10,000 years
Appendix C: Tables Comparing the Modeled
or Extrapolated Risk Levels vs. the EQCs
for Each Constituent
Appendix D: Tables Comparing the Exit
Levels and the UTS Levels
Regulatory Language
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66346
Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 ./ Proposed Rules
I. Authority
These regulations are proposed under
the authority of sections 2002(a), 3001,
3002, 3004 and 3006 of the Solid Waste
Disposal Act of 1970, as amended by the
Resource Conservation and Recovery
Act of 1976 (RCRA), as amended by the
Hazardous and Solid Waste
Amendments of 1984 (HSWA), 42
U.S.C. 6912(a), 6921, 6922, 6924 and
6926.
II. Background
A. Overview of the Hazardous Waste
Identification Program
Section 1004(5) of the Resource
Conservation and Recovery Act (RCRA)
as amended by the Hazardous and Solid
Waste Amendments (HSWA) of 1984,
defines "hazardous waste" as "a solid
waste, or combination of solid waste,
which because of its quantity,
concentration, or physical, chemical, or
infectious characteristics may (A) cause,
or significantly contribute to an increase
in the mortality or an increase in serious
irreversible, or incapacitating reversible,
illness; or (B) pose a substantial present
or potential hazard to human health or
the environment when improperly
treated, stored, transported, or disposed
of, or otherwise managed."
Section 3001 of RCRA requires EPA to
identify those wastes that should be
classified as "hazardous." The Agency's
hazardous waste identification rules
designate wastes as hazardous in one of
two ways. First, the Agency has
established four hazardous waste
characteristics which identify properties
or attributes of wastes which would
pose a potential hazard if the waste is
improperly managed. See 40 CFR
261.21-261.24. Any generator of a solid
waste is responsible for determining
whether a solid waste exhibits any of
these characteristics. See 40 CFR 262.11.
Any solid waste that exhibits any of the
characteristics remains hazardous until
it no longer exhibits the characteristics.
See 40 CFR 261.4(d)(l).
The other mechanism EPA uses to
designate wastes as hazardous is
"listing." The Agency has reviewed data
on specific waste streams generated
from a number of industrial processes
and has determined that these wastes
would pose hazards if mismanaged for
one or more reasons, including the
presence of Significant levels of
hazardous constituents listed in
appendix VIII to 40 CFR part 261, the
manifestation of one or more of the
hazardous waste characteristics, or the
potential to impose detrimental effects
on the environment. (See generally 40
CFR 261.(11). As discussed in detail in
the preambles and in associated dockets
accompanying the listings, EPA has
generally determined that these wastes
contain toxic constituents at
concentrations which pose risks which
are unacceptable for human or
environmental exposure and that these
constituents are mobile and persistent to
the degree that they can reach
environmental or human receptors.
On May 19, 1980, as part of the final
and interim final regulations
implementing section 3001 of RCRA,
EPA published two lists of hazardous
wastes: One composed of wastes
generated from non-specific sources
(e.g., spent solvents) and one composed
of wastes generated from specific
sources (e.g., distillation bottoms from
the production of benzyl chloride). The
Agency also published two lists of
discarded commercial chemical
products, off-specification species,
container residues, and spill residues
thereof which are hazardous wastes
under specific circumstances. These
four lists have been amended several
times, and are currently published in 40
CFR 261.31, 261.32, 261.33(e) and (f),
respectively.
B. The Mixture and Derived-From Rules
and the Contained-In Policy
1. Mixture and Derived-From Rules
a. Scope and Purpose of the Rules
In 1980 EPA promulgated its first
comprehensive regulatory program for
the' management of hazardous waste
under RCRA. 45 FR 33066 (May 19,
1980). As part of that rulemaking EPA
promulgated several rules to identify
hazardous wastes. Two of these rules
clarify the scope of the hazardous waste
listings. Under the mixture rule, a solid
waste is a hazardous waste if it is mixed
with one or more listed hazardous
wastes. 40 CFR 261.3(a)(2)(iv). Under
the derived-from rule a solid waste
generated from the treatment, storage or
disposal of a listed hazardous waste is
also a hazardous waste. 40 CFR
EPA promulgated the mixture and
derived-from rules to close potentially
major loopholes in the subtitle C
management system. Without a
"mixture" rule, generators of hazardous
wastes could potentially evade
regulatory requirements by mixing
listed hazardous wastes with other
hazardous wastes or non-hazardous
solid wastes to create a "new" waste
that arguably no longer met the listing
description, but continued to pose a
serious hazard. Such a waste also might
not exhibit any of the hazardous waste
characteristics. Similarly, without a
"derived-from" rule, hazardous waste
generators and owners and operators of
hazardous waste treatment, storage, and
disposal facilities (TSDFs) could
potentially evade regulation by
minimally processing or managing a
hazardous waste and claiming that
resulting residue was no longer the
listed waste, despite the continued
hazards that could be posed by the
residue even though it does not exhibit
a characteristic. (See 57 FR 7628).
It is for these reasons that the Agency
continues to believe that the mixture
and derived-from rules are extremely
important in regulating hazardous
wastes and reducing risk to human
health and the environment. However,
EPA acknowledges that the mixture and
derived-from rules apply regardless of
the concentrations and mobilities of
hazardous constituents in the waste.
The purpose of this rulemaking is to
reduce any overregulation of low-risk
wastes captured by the mixture and
derived-from rule.
b. Subsequent History
Numerous industries that generate
hazardous wastes challenged the 1980
mixture and derived-from rules hi Shell
Oil v. EPA, 950 F. 2d 741 (D.C. Cir.
1991). hi December 1991 the D.C. circuit
vacated the rules because they had been
promulgated without adequate notice
and opportunity to comment. The court,
however, suggested that EPA might
want to consider reinstating the rules
pending full notice and comment in
order to ensure continued protection of
human health and the environment.
In response to this decision, EPA
promulgated an emergency rule
reinstating the mixture and derived-
from rules as interim final rules without
providing notice and opportunity to
comment. 57 FR 7628 (Mar.3, 1992).
EPA also promulgated a "sunset
provision" which provided that the
mixture and derived-from rules would.
remain in effect only until April 28,
1993. Shortly after, EPA published the
proposal containing several options for
revising the mixture and derived-from
rules. See 57 FR 21450 (May 20, 1992).
This proposal also included options for
exempting media contaminated with
listed hazardous wastes that are
regulated under the "contained in"
policy.
The May 1992 proposal and the time
pressure created by the "sunset
provision" generated significant
controversy. In response, Congress
included in EPA's 1992 appropriations
bill several provisions addressing the
mixture and derived-from rules. Pub. L.
No. 102-389, 106 Stat. 1571. First,
Congress nullified the sunset provision
by providing that EPA could not
promulgate any revisions to the rules
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Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66347
before October 1,1993 and by providing
that the reinstated regulations could not
be "terminated or withdrawn" until
revisions took effect. However, to ensure
that EPA could not postpone the issue
of revisions indefinitely, Congress also
established a deadline of October 1,
1994 for the promulgation of revisions
to the mixture and derived-from rules.
Congress made this deadline
enforceable under RCRA's citizen suit
provision.
On October 30,1992 EPA published
two notices, one removing the sunset
provision, and the other withdrawing
the May 1992 proposal. See 57 FR
49278,49280. EPA had received many
comments criticizing the May 1992
proposal. The criticisms were due, in a
large part, to the very short schedule
imposed on the regulation development
process itself. Commenters also feared
that the proposal would result in a
"patchwork" of differing State programs
because some states might not adopt the
revisions. This fear was based on the
belief that States would react in a
negative manner to the proposal and
refuse to incorporate it into their
programs. Finally, many commenters
also argued that the risk assessment
used to support the proposed exemption,
levels failed to provide adequate
protection of human health and the
environment because it evaluated only
the risks of human consumption of
contaminated groundwater ignoring
other pathways that could pose greater
risks. Based on these concerns, and
based on the Agency's desire to work
through the individual elements of the
proposal more carefully, the proposal
was •withdrawn.
Meanwhile, a group of waste
generating industries challenged the
March 1992 action that reinstated the
mixture and derived-from rules without
change. Mobil Oil Corp. v. EPA, 35 F.3d
579 (D.C. Cir. 1994). EPA argued that
the 1992 appropriations act made the
challenge moot because it prevented
both EPA and the courts from
terminating or withdrawing the interim
rules before EPA revised them, even if
EPA failed to meet the statutory
deadline for the revisions. In September,
1994 the D.C. Circuit issued an opinion
that dismissed the challenges as moot
under the rationale that the Agency had
offered.
In early October 1994 several groups
of waste generating and waste managing
industries filed citizen suits to enforce
the October 1 deadline for revising the
mixture and derived-from rules. The
U.S. District Court for the District of
Columbia Circuit entered a consent
decree resolving the consolidated cases
on May 3,1993. Environmental
Technology Council v. Browner, C.A.
No. 94-2119 (TFH) (D.D.C. 1994) Under
this decree the Administrator must sign
a proposal to amend the mixture and
derived-from rules by November 13,
1995 and a notice of final rulemaking by
December 15,1996. The decree also
specifies that the deadlines in the 1992
appropriations act do not apply to any
rule revising the separate regulations
that establish jurisdiction over media
contaminated with hazardous wastes.
c. Federal Advisory Committees Act
(FACA) and Outreach
After the withdrawal of the HWIR
proposal, the Agency initiated a series
of public meetings with invited
representatives from industry,
environmental groups, hazardous waste
treaters, and States. These meetings
focused on three major issues: —RCRA
regulation of low hazard wastes with a
particular interest in addressing issues
raised regarding the mixture and
derived-from rules; concerns that full
RCRA requirements for contaminated
media may unnecessarily impede clean-
ups; and need to regulate additional
high-risk wastes outside the scope of the
current listings and characteristics.
A strong and successful effort was
made to encourage all the interested
parties to participate in the public
meetings. EPA forged a solid
partnership with the States (both
ASTSWMO and Environmental
Commissioners under the National
Governors Association) and the state
representatives worked closely with
EPA as co-regulators in our analyses of
options.
In July of 1993, EPA chartered this
group as an advisory committee under
the Federal Advisory Committee Act
(Pub. L. 92-463)(58 FR 36200).
The committee rather quickly formed
two sub-committees to allow separate
discussion of the low risk waste
problem associated with the mixture
and derived-from rules and the rules for
managing contaminated media and
other wastes during remediation.
By September of 1994 the low risk
waste group had made significant
progress in identifying options for
creating exemptions for low risk wastes.
Despite significant investment of time
and effort, however, the group was
unable to reach consensus on many key
issues.
With the statutory deadline for
revisions to the mixture and derived-
from rules approaching, EPA requested
that group to present a final report in
late September of 1994. EPA and
representatives from several state
environmental agencies then took up
the task of selecting options for creating
an exit rule, crafting regulatory
language, and developing necessary
supporting materials. The FACA
subcommittee's final report was taken
into consideration during the
development of today's proposal.
2. Contained-In Policy
The Agency also has interpreted its
regulatory definition of hazardous waste
to extend to mixtures of hazardous
wastes and environmental media (such
as contaminated soil and groundwater).2
See 40 CFR 261.3(c)(l) and (d)(2). Media
that are contaminated with listed or
characteristically hazardous waste must
be managed as hazardous wastes until,
they no longer contain such wastes. To
date, the Agency has not issued any
general rules as to when, or at what
levels, environmental media
contaminated with hazardous wastes are
no longer considered to "contain" those
hazardous wastes. Media that contain
hazardous wastes with constituent
concentrations below the levels
proposed today will be eligible for
exemption under the procedures
proposed today. In addition, in a
separate rulemaking, the Agency plans
to propose additional rules reducing
regulation of contaminated media
during remediation activities.
C. Overview of Expected Impacts of the
Exit Rule
1. Listed Wastes
The purpose of this rule is to exempt
from hazardous waste regulation those
solid wastes currently designated as
hazardous waste even though they
contain constituent concentrations at
levels that pose very low risk to human
health and the environment. While
facilities generating such wastes can
petition for delisting by rulemaking
under the provisions of 40 CFR § 260.20
and 260.22, EPA believes that the
detailed waste-stream specific review
required under delisting is not
necessary for the low risk wastes that
are identified by today's proposal. The
alternative, generic exit rule proposed
today will be faster and less resource-
intensive for both the Agency and the
regulated community. By providing an
opportunity for a more self-
implementing exemption, the Agency
intends to create incentives for effective
and innovative waste minimization and
waste treatment and to reduce
unnecessary demand for Subtitle C
disposal capacity, without
2EPA's "contained in" policy was upheld as a .
reasonable interpretation of 40 CI^R 261.3(c)(i) and
(d)(2),by the D.C. Circuit in Chemical Waste
Management, Inc v, U.S. EPA, No. 869 F.2d 1526
(D.C. Cir. 1989).
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66348 Federal Register /-Vol. 60,'No. 245:/ Thursday, December 21, 1995 / Proposed Rules
compromising needed environmental
protection.3 . . '. •. •• . -•
By proposing a risk-based "floor" to
listed wastes, today's proposal should
give a very strong incentive to .
generators of listed hazardous waste to '
apply pollution prevention to their
processes to avoid Subtitle C control.
This action should also give incentive
for the development of innovative; '
treatment technologies to render wastes
less risky. '
Today's proposed rule specifies
sampling and analysis requirements,
public participation, reporting and •
record keeping requirements. Most of
these provisions are alternatives to the
safeguard of waste-specific review
provided under the delisting program.
The exit levels are risk-based
concentrations at which a human or
wildlife species could be directly or
indirectly exposed to the exempted
waste, and would be unlikely to suffer
adverse health effects. The exposure
scenario used to develop these levels
assume that the exempted waste will no
longer be subject to Subtitle C control,
but will be managed as a solid waste in
one of a variety of non-hazardous waste
management units regulated under
Subtitle D.
2. Characteristic Wastes
Listed hazardous wastes exempted
under today's proposed rule which
exhibit any of the characteristics will
continue to be regulated as hazardous
wastes until the characteristic is
removed. In a number of cases, wastes
were listed on the basis of containing
both toxic hazardous constituents,and
exhibiting one or more of the hazardpus
waste characteristics that do not relate
to chemical toxicity (e.g., ignitability,
corrosivity, or reactivity). If such a,
waste still exhibits any characteristic
after complying with the exemption
criteria proposed in today's proposed
rule, it must continue to be managed as
a characteristically hazardous waste.
III. Scope of Revisions to the Mixture
and Derived-From Rules
The mixture and derived-from rules
promulgated in 1980 and reinstated in
1992 require Subtitle C regulation of all
mixtures of listed hazardous wastes and
solid wastes and all residuals from
treatment of hazardous wastes. The
rules proposed today, however, allow
rapid exemptions for mixtures and
3 As will be discussed further in this notice, the
Agency believes that the delisting process will
continue to be valuable for certain types of wastes
which are not eligible for an exemption under this
proposal. Thus the Agency is not proposing to
eliminate or modify the delisting program as a •
result of this proposal. ' '
derived-from wastes that present no
significant threats to human health and
the environment: Those wastes that
would remain subject to the mixture
and derived-from rules typically will
pose risks that warrant regulation under
Subtitle C. To the extent that this is not
true for a particular mixture or • -'
treatment residual, the delisting process
remains available (at least at the state •
level) to exempt wastes with
constituents at more site- and waste-
specific levels. Consequently, EPA has
tentatively determined that further
revisions of the mixture and derived-
from rules, with the exception of the
one minor change to the derived-from
rule discussed later in this section, are
not warranted in this rulemaking.
However, EPA requests comment on
this conclusion.
A. Rationale for Retention of the
Mixture and Derived-From Rules
EPA continues to believe that it had
ample statutory and regulatory authority
to promulgate the original rules and that
it also has ample authority to maintain
the rules without further revisions. The
mixture and derived-from rules,
particularly with the revisions proposed
today, ensure that hazardous wastes that
are mixed with other wastes or treated
in some fashion do not escape
regulation so long as they are reasonably
likely to continue to pose threats to
human health and the environment.
They thus retain jurisdiction over listed
hazardous wastes and clarify that such
wastes are not automatically eligible for
exit when they are mixed or treated.
Although. RCRA sets out criteria for the
identification of hazardous wastes to
enter the subtitle C system, it is silent
on the question of how to determine ,
that a waste is eligible to exit the
system. EPA's interpretation of the
statute is thus entitled to deference so
long as it is reasonable and consistent
with RCRA's purposes.
EPA believes that its decision to
retain jurisdiction over major portions
of the universe of waste mixtures and
treatment residues is consistent with its
authorities under sections 3002-3004 of
RCRA to impose requirements on waste
handlers until wastes have "cease[d] to
pose a hazard to the public". Shell Oil
Corp. v. EPA, 959 F.2d 741, 754 (D.C.
Cir. 1991). See also Chemical
Manufacturers Assoc. v. EPA, 919 F.2d
158; 162-65 (EPA may regulate the
disposal of honhazardous wastes in a
hazardous waste impoundment under
section 3004) and Chemical Waste
Management, Inc. v. EPA, 976 F.2d 2; 8,
13-14 p.C; Cir. 1992) (EPA may require
further treatment of wastes under
section 3004 even though they cease to
exhibit a hazardous characteristic).
The mixture and derived-from rules
are also valid exercises of EPA's
authority to list hazardous wastes under
section 3001. That provision gives EPA
broad authority to promulgate listing
criteria. EPA's 1980 criteria authorize
the listing of classes of hazardous
wastes when it has reason to believe
that wastes in the class are typically or
frequently hazardous. See 40 CFR
261.11(b). Such class listings are
permissible even if some members of
the class do not actually pose hazards.
Nothing in the section 1004(5)
definition of hazardpus waste, in section
3001, or in EPA's listing criteria require
EPA to prove that every member of a
class poses,a hazard, hi fact; many waste
listings describe "classes" of hazardous
wastes because they cover a range of
materials that are not identical in
composition. The mixture and derived-
from rules thus are fully authorized as
class "listings" under section 3001.
EPA has also made a reasonable
factual determination that these classes
of waste warrant regulation under
sections 3002-3004 and section 3001. In
1980 EPA determined that the
hazardous constituents contained in
these wastes are not generally
eliminated or rendered nontoxic simply
because a waste is mixed with other
wastes or managed in some fashion. In
1992, when EPA repromulgated the .
mixture and derived-from rules, it
documented numerous instances of
mixed and derived-from wastes that
continued to pose hazards. Se'e 57 FR
7629 (March 3, 1992). Today, EPA is
proposing that members of this class of
wastes that pose low risks.will be
eligible for an expedited, self-
implementing exemption from Subtitle
C regulation. Accordingly, EPA has an
even better basis for believing that
wastes which remain within the scope
of the mixture and derived-from rules
pose threats warranting regulation.
Additionally, EPA continues to
believe, as it did in 1980, that it would
be virtually impossible to try to identify
all possible waste mixtures and treated
wastes and assess their hazards
individually. EPA's rule reasonably
retains jurisdiction over both broad
classes and places the burden of proof
on the regulated community to show
that a particular waste has ceased to
present a hazard. Today's self-
implementing exit proposal will reduce
that burden significantly, ensuring that
the mixture and derivedrfrom rules
represenFa reasonable approach to
regulating these classes of wastes.
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Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66349
B, Revision to Derived-from Rule for
Wastes Listed Because They Exhibit the
Characteristics of Ignitability,
Corrosivity, or Reactivity
In 1981 EPA responded to a number
of comments on the scope of the original
1980 mixture rule by promulgating a
number of exemptions for mixtures of
solid wastes and listed hazardous
wastes which, according to information
submitted by commenters, posed no
significant risk to human health and the
environment. See 46 FR 56582 (Nov. 17,
1981). The 1981 rule included an
exemption for mixtures of solid wastes
and hazardous wastes listed solely
because they exhibited one or more of
the hazardous waste characteristics, if
the resultant mixtures no longer
exhibited a characteristic. The
exemption was based on a finding that
such mixtures did not pose threats to
human health and the environment
warranting Subtitle C regulation. See 46
FR 56568 and the current text of the
exemption at § 261.3(a)(2)(iii). EPA
notes that it has never promulgated any
listings for wastes solely on the basis
that they exhibit either the 1980 EP
toxicity characteristic or the 1990
toxicity characteristic; consequently,
only mixtures containing wastes listed
because they exhibit the characteristics
of ignitability, corrosivity; or reactivity
have been eligible to exit Subtitle C
when they no longer exhibit the
characteristic.
The 1981 notice focused exclusively
on issues concerning the mixture rule.
Consequently, EPA did not propose any
parallel exemption for such wastes for
the separate derived-from rule (codified
at § 261.3(c)(2)(i)), even though the
derived-from wastes would appear to
present similarly low risks if they no
longer exhibited a characteristic and
were treated to meet LDR standards
before land disposal. Recent inquiries
from the public have highlighted the
discrepancy in the scope of the mixture
rule and the derived-from rule for
wastes listed solely because they exhibit
characteristics. EPA believes it has no
reason to treat derivatives of wastes
listed solely because they exhibit the
characteristic of ignitability, corrosivity,
or reactivity any differently from the
way it treats mixtures of such wastes
because both present similar low risks
to human health and the environment.
Consequently, EPA is today proposing
a revision to the derived-from rule that
will closely resemble the 1981 revision
to the mixture rule. Since no listings to
date have been based on the toxicity
characteristic, EPA is proposing to limit
the new revision to the derived-from
rule to wastes listed because they
exhibit only the characteristics of
ignitability, corrosivity, or reactivity.
EPA is also not proposing to exempt
wastes that might in the future be listed
only because of the toxicity
characteristic because (as this rule
proposal indicates) there can be risk
concerns with the TC constituents
below TC levels. EPA requests comment
on this proposal to create a new
exemption to the derived-from rule for
this limited category of listed wastes.
The proposed exemption will also
remind the regulated community of the
separate duty to comply with
requirements imposed by the part 268
regulations implementing the LDR
program. In CWMv. EPA, 976 F.2d 2
(B.C. Cir. 1992), the U.S Court of
Appeals for the B.C. Circuit interpreted
RCRA section 3004(m) as requiring
treatment of de-characterized hazardous
wastes to meet LBR treatment standards
even after the wastes cease exhibiting a
characteristic. EPA believes that de-
characterized derived-from residues
from wastes listed because they exhibit
characteristics also must meet LDR
requirements, unless they are either
delisted or are exempt at the point of
generation pursuant to other provisions
proposed in this rule (e.g., meeting
HWIR levels at the point of generation).
In 1992 EPA amended the 1981
exemption to mixture rule to provide a
•similar cross-reference and clarification
for mixtures containing de-characterized
listed wastes. See 57 FR 37194, 37210-
11 (Aug. 18, 1992). That 1992
clarification, however, only covers
nonwastewater mixtures. As explained
in that mixture rule preamble, EPA then
regulated de-characterized wastewaters
much less stringently under the LBR
program. Consequently, EPA did not
believe it was necessary to remind the
regulated community to comply with
LBR requirements for wastewater
mixtures.
Later in 1992 the CWMv. EPA
decision invalidated most of the
distinctions between the LBR rules for
wastewaters and nonwastewaters. EPA
is now revising the LBR program to
comply with that decision in the LBR
Phase III and Phase IV rulemakings. To
reflect the changes in LBR regulation of
wastewaters, the derived-from rule
exemption proposed today reminds the
regulated community of the need to
comply with part 268 LDR requirements
for all types of derived-from residues.
EPA requests comment on this
clarifying language. EPA also requests
comment on whether it should revise
the LBR clarification for the mixture
rule as well.
IV. Development of Exit Levels and
"Minimize Threat" Levels
A. Need for the Exit
The primary purpose of this rule is to
address listed hazardous wastes,
mixtures of listed hazardous wastes and
solid wastes, and residues derived-from
managing listed hazardous waste that,
under current rules, continue to be
designated as "hazardous waste"
although they are either generated with
constituent concentrations that pose low
risks or treated in a manner that reduces
constituent concentrations to low levels
of risk.
EPA notes that there are currently
exemptions, both codified and
contained in policy directives, from the
hazardous waste identification system,
particularly the mixture and derived-
from rules, for certain types of wastes or
wastes with certain constituent
concentrations. See e.g. 40 CFR
261.3(a)(2)(iv)(A) through (E) and policy
memorandums such as the "Skinner
Memorandum" dated August 23,1995.
EPA is not proposing to modify or
replace any of these exemptions and
policy statements.
B. Overview of the Exit
For 191 of the 376 constituents of
concern, EPA conducted a detailed
human health risk analysis to develop
risk-based levels for either the
wastewater or nonwastewater form of a
constituent (or both). To conduct this
analysis, EPA identified five types of
units actually and rather frequently
used to manage nonhazardous wastes
that covered the full range of
environmental releases needing
analysis. The May 1992 proposal of exit
levels for listed wastes, like many
previous RCRA rules, assessed only
risks from releases to groundwater. In
response to complaints that such an
assessment would not protect human •
health and the environment from other
types of releases, EPA also assessed
potential releases to air, surface water
and soil in this proposal.
For each category of releases, EPA
evaluated both relatively simple
pathways (such direct human ingestion
of contaminated groundwater) and more
complex pathways (such as the
deposition of windblown waste
particles on agricultural land, followed
by crop uptake, consumption of the crop
by cattle, and consumption of
contaminated beef or milk by humans).
EPA assessed approximately 8 to 27
release pathways depending on the type
of waste management unit.
Additionally, EPA screened the same
group of 191 constituents to identify the
highest priorities for assessment of
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66350 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
ecological receptors. In addition, EPA
considered for its assessment the
toxicological effects of silver on
ecological receptors. EPA conducted a
specific assessment of ecological risks
for 47 constituents using the same five
units and the same pathways (modified
to reflect ecological exposures)-for each
unit. This risk assessment is described
in more detail in sections V.B. and C.
Data limitations and resource
constraints prevented EPA from
conducting a risk analysis for the
remaining constituents of concern. For
each of these constituents, EPA
extrapolated exit levels from levels
derived-from the risk assessment for
similar chemicals. EPA's extrapolation
methodology is described in section
IV.F.
The current capabilities of analytical
chemistry constrain EPA's ability to use
some of concentrations as exit levels.
For approximately one-fourth of the
constituents, EPA found that available
methods could not routinely measure
the constituent at the modeled or
extrapolated risk-based exit level.
C. Selection of Constituents of Concern
1. Development of the Master List
EPA developed an initial "Master
List" of 506 constituents to be evaluated
for purposes of establishing exit criteria.
This master list was developed by
combining the constituents specifically
listed in the following appendices of 40
CFR part 261: Appendix VII, Basis for
Listing Hazardous Waste; Appendix
VIII, Hazardous Constituents; and
appendix IX of part 264, the Ground-
Water Monitoring List. The master list
includes the full list of constituents
referenced in appendix VII, including
the F039 constituents.
Appendix VII to part 261, which was
originally promulgated on May 19,1980
(45 FR 33084) sets out the chemical
constituents found to pose threats to
human health and the environment that
served as the actual basis for each of
EPA's original hazardous waste listings.
Appendix VIII to Part 261, also
promulgated in 1980, is a more general
listing of chemicals found to pose
potential threats to human heakh and
the environment. (45 FR 33084). EPA
considers wastes containing appendix
VIII constituents to be candidates for
listing determinations. EPA amends
appendix VII from time to time as EPA
identifies additional potentially toxic
constituents.
EPA later promulgated appendix IX to
part 264 to identify those appendix VIII
constituents which it could routinely
expect owners and operators of
permitted hazardous waste treatment,
storage and disposal facilities to monitor
in groundwater. EPA also included in
this appendix 17 additional constituents
found to pose significant risks that the
Superfund program routinely monitored
in groundwater. (52 FR 25942, July 9,
1987).
EPA established in these rulemakings
that each of these constituents had
significant potential to threaten human
health, and, by implication, potential to
threaten the environment. (Most of the
data EPA utilized predicted.toxic effects
on humans.) EPA finds it reasonable to
include each of these constituents on
the list of chemicals of concern.
Further, EPA believes that, with the
exception of the six chemicals identified
below, the three appendices identify the
chemicals of current concern to EPA
that are likely to be found in listed
wastes.
The Agency requests comment on
whether the master list should also
include six constituents that are not
listed in any of the above sources. These
six constituents, which are listed in
Table 1, are found in six "U" listed
wastes (commercial chemical products
that become hazardous wastes when
discarded). See 40 CFR 261.33(f). EPA
originally listed these wastes because
they routinely exhibited the
characteristic of ignitability. Since the
original listings, however, sufficient
toxicity data have become available for
these constituents. (The risk number for
dimethylamlne was recently withdrawn;
however, EPA understands that it will
shortly be replaced). Because of the
toxicity data associated with these
constituents, the Agency is taking
comment on whether exit levels should
be established for these six constituents
in today's rulemaking. The Agency also
requests comment on whether these six
constituents should be added to
Appendix VIII.
TABLE 1 .—CONSTITUENTS NOT ON APPENDICES VII, VIII, OR IX
CAS#
Constituent
Wastewater
Nonwastewater
Totals
Leach
75-07-0 Acetaldehyde (ethanal)
98-82-8 Cumene
124-40-3 Dimethylamine
110-00-9 Furan
79-10-7 Acrylic acid
98-01-1 2-Furancarbox- aldehyde (furfural)
.67
18,000
2.5
.16
1300
:1)
.06
(1)
1 No exit levels because no EQC is available for this constituent. The criteria for exit would be to meet LDR treatment standards in §268.
Full documentation concerning the
selection of constituents of concern is
available in the docket under The
Background Document to Support
Development of the Final Constituent
List under the Waste Exit Rule,
2. Development of the Exit Constituent
List
The Agency narrowed the list of 506
constituents to consist of 376
constituents that are included in the
exemption list. 130 constituents were
deleted from the master list. Criteria for
constituent deletions from the master
list include: Reactivity in air, analysis as
a different constituent, reactivity in
water, hydrolysis in soil or water, or is
part of a chemical class with a specific
constituent represented on the list.
Because different methods and
quantitation limits are necessary for
solid and liquid matrices, two separate
analyses were conducted. The
Background Document to Support
Development of the Final Constituent
List under the Waste Exit Rule in the
docket further justifies deletions of
constituents from the master list and
lists the deleted constituents.
Molybdenum is not on the
Appendices VII, VIII, or IX, which
provided the scope of today's master list
of constituents. In anticipation of the
Petroleum listing, due to a Drinking
Water Sewage Sludge regulatory level,
and due to available toxicity
information, the Agency has included
molybdenum on the exemption list. Due
to modeling time constraints,
Molybdenum was not modeled for
groundwater risk. The groundwater
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Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66351
leach level was estimated by assuming
a DAF of 10 and using the RfD. The
Agency requests comment on whether
molybdenum should be on the list.
Two modeled constituents do not
have estimated quantitation criteria
(EQCs—see section IV.G.) and therefore
do not have associated exit levels. These
constituents are ethylene thiourea and
phenyl mercuric acetate. The Agency
requests comment on how to deal with
these two constituents. The following
table represents modeled results for
these constituents for comment.
TABLE 2.—MODELED CONSTITUENTS WITHOUT EQCs
CASNUM
Constituent
NWW totals NWW leach WW totals
95_45-7
62-38-4
Ethylene thiourea
0.51
0.0093
0.00017
0.0045
.00053
0.012
EPA modeled chromium VI in the risk
assessment. However, totals chromium
appears on the exit tables based on the
exit levels calculated from modeling
chromium VL This approach is
consistent with the Toxicity
Characteristic approach to chromium.
The Agency asks for comment on this
approach.
The cyanide exit level was
extrapolated. It is meant to be totals
cyanide. The Agency requests comment
on whether testing for totals cyanide is
appropriate.
The values in the exit tables for silver
do not represent results of human
toxicity data for silver, rather they
represent ecological results from the risk
assessment. The Agency has determined
that the effect of silver on humans is not
a human health problem, rather it is an
aesthetic problem. The groundwater
model did not model ecological
exposure, therefore, there is no
groundwater risk level for silver.
3. Constituents of Ecological Concern
As explained above, EPA established
in previous RCRA rulemakings that the
constituents on the exit list (376)
present significant threats to human
health. Numerous comments submitted
on EPA's May 1992 proposal to
establish exit levels urged EPA to
conduct a more specific and detailed
analysis of threats to non-human
species. Consequently, in this
rulomaking EPA determined the
constituents it believed to also be
reasonably likely to pose risks to
ecological receptors.
EPA has not set benchmarks for
ecological impacts for a large number of
constituents under any of its programs.
Establishing such benchmarks for this
proposal would be a resource-intensive
and time-consuming task. Accordingly,
EPA narrowed the list of exit
constituents for which ecological
receptors would be evaluated. First,
EPA decided to consider only the 191
constituents which it had already
targeted for analysis to protect human
health. Second, the Agency developed a
methodology for screening the 191
constituents to identify those most
likely to pose significant risks to
ecological receptors.
Based on an extensive review of
available literature, EPA developed five
criteria to indicate the potential for
ecological risks:
(1) Constituents that bioaccumulate
(and possibly biomagnify) in the food
chain that can present elevated
exposures to certain predators;
(2) Persistent constituents that are
likely to increase long-term multi-
generational exposures in wildlife;
(3) Constituents that cause
reproductive and developmental effects
that can elicit adverse effects at
sensitive life stages;
(4) Constituents that may cause
ecological effects that have no human
analog (e.g., eggshell thinning); and
(5) Constituents that may cause effects
to ecological receptors continuously
exposed.
EPA also developed operational
definitions for each criterion. The
definitions were quantitative where
possible. Further details can be found in
appendix B of the Technical Support
Document for the Risk Assessment for
Human and Ecological Receptors.
EPA decided to designate as
constituents of ecological concern the
47 constituents that exhibited at least
two of the five criteria. The Agency
believes these constituents present the
highest priorities in terms of
environmental risk. An additional 36
constituents exhibited only one
criterion. EPA, however, chose not to
designate them as constituents of
concern because time and resource
constraints would prevent the Agency
from completing an analysis with these
constituents. EPA, nevertheless,
believes it has identified and analyzed
sufficient constituents of concern to
ensure that the exit levels proposed
today provide for reasonable protection
of the environment. Only 83 of 191
screened constituents showed any
significant potential to pose threats to
the environment at levels protective of
human health. Further, as discussed in
more detail below, of the 47
constituents that EPA actually assessed
for ecological impacts, only 6
wastewater constituents and 18
nonwastewater constituents required
exit levels to protect environmental
receptors lower than those necessary to
protect human health under the baseline
proposal. Consequently, EPA believes it
is unlikely that all of the remaining
constituents will present significant
threats to ecological receptors at levels
that would adequately protect human
health.
D. Risk-Based Information
The Agency's proposed option for
establishing exit values is based on risk
modeling to a hazard quotient of 1 and
a 1x10~6 cancer risk. The Agency
chose a hazard quotient of 1 as its
toxicity benchmark value for non-
carcinogens because evaluation of these
compounds presumes there is a
threshold exposure above which
individuals would be at significant risk
of suffering the adverse effects
attributable to the compound. The HQ is
the Agency's best attempt to estimate
that level. Therefore, the Agency
believes all exposures should remain
below HQ 1. Some Agency programs
rely on HQ values less than 1 in
standard setting (the drinking water
program uses an HQ of 0.20 to provide
a safety factor which allows for
exposure to the constituent from sources
other than drinking water).
The Agency chose a toxicity
benchmark of 1 x 10-6 cancer risk for
carcinogens for several reasons. A
cancer risk level of 1 x 10-5 risk was
used as a clearly hazardous level in
establishing the toxicity characteristic. •
Second, in the listings program, a 1 x
1CH cancer risk is used as the
presumptive listing risk, and a 1 x 10-6
as the presumptive no-list level. A
cancer risk of 1 x 10-5 represents a level
of initial concern about risk. Therefore,
in allowing listed hazardous waste to
exit the requirements of Subtitle C, the
Agency was targeting waste that is
clearly not hazardous. Thus, the Agency
believes the risk level should be at the
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66352 Federal Register /Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
low end of the risk range used to bring
waste into the hazardous waste system.
Similarly, the Agency sought to be '
protective of public health in
developing its fate and exposure
modeling. For the groundwater
evaluation, the Agency used a DAF 10
(which represents an approximate 90th
percentile protection level) for infinite
source type constituents. (Constituent-
specific DAFs were developed using the
same input assumptions, and different
DAFs result from modeling of
degradation or retardation factors in the
environment). This is the generic DAF
used in the delisting program for large
volume wastes. Since this is a national
program which will largely benefit the
largest volume generators, the DAF 10
assumption is consistent with delisting
practice. Also, the toxicity characteristic
used a DAF of 100 (representing an
approximate 85th percentile protection
level) for identifying clearly hazardous
waste (for infinite source type
constituents; regulation of hydrolysers
was deferred). Again the policy goal of
exits was to strive to be well below
clearly hazardous levels. The Agency
also modeled exposure at the nearest
downgradient well. The TC rule
restricted well placement to within the
plume. Today's proposal attempts to
balance the protectiveness level and
well placement by requiring a more
protective level than the TC rule, but is
less restrictive in well location, e.g.,
wells outside of the plume, at
significantly lower risk, are averaged in.
For modeling of the non-groundwater
pathways, the Agency used four high-
end parameter values for which the
modeling outcome is most sensitive as
inputs to the analysis to be protective of
public health and the environment.
These include: Two high-end
parameters in the waste management
unit characterization and'fate portions
and two high-end parameters in the
exposure portions of the model. The
remaining input parameters were
evaluated at typical values or central
tendency values. The Agency sought to
be protective of a high percentile
exposed population (at least 90th
percentile).
1. Human Health Benchmarks
For each constituent on the master
list, the Agency evaluated the existing
toxicity information to determine
whether there were sufficient toxicity
data to establish a benchmark. For those
constituents with adequate data, the
data were evaluated either by the
Agency's CRAVE (Carcinogen Risk
Assessment Verification Endeavor)
Workgroup, Reference Dose/Reference
Concentration (RfD/RfC) Workgroup, or
the Office of Research and
Development. This approach is
consistent with the approach used in
the Agency's other risk-based RCRA
programs such as the Toxicity
Characteristic, delisting petition
evaluations, listings, as well as the
CERCLA program. See Section 4,
"Benchmarks," of the Technical
Support Document for the Hazardous
Waste Identification Rule: Risk
Assessment for Human and Ecological
Receptors for more details.
a. Non-carcinogens
The Agency proposes to use oral
reference doses (RfDs) and inhalation
reference concentrations (RfCs) as the
basis for developing the exit criteria for
non-carcinogenic constituents. An RfD
or RfC is an estimate (with uncertainty
spanning perhaps an order of
magnitude) of a daily exposure to a
constituent for the human population
(including sensitive subgroups) that is
likely to be without an appreciable risk
of deleterious effects during a lifetime.
The approach used to derive an RfD
or RfC is to identify the highest test dose
of a constituent associated with no
effects,or effects that are not considered
adverse in an appropriate animal
bioassay test. These experimental no-
observed-adverse-effect-levels
(NOAELs) or no-observed-effect-levels
(NOELs) are considered to be an
estimate of the animal population's
physiological threshold for adverse
effects. The RfD or RfC is derived by
dividing the NOAEL or other toxicity
benchmark by suitable uncertainty and
modifying factors. In the event that an
appropriate NOAEL or NOEL is not
available, the lowest-observed-adverse-
effect level (LOAEL) may be used with
additional uncertainty factors.
It is important to note that the
contributions of the constituent from
various sources in the environment (e.g.,
air, food, water) are not considered in
the development of an RfD or RfC.
Rather, the RfD or RfC reflects the
estimated total permissible daily human
exposure from all sources of exposure.
RfDs and RfCs have been calculated for
many, but not all, of the non-
carcinogenic constituents for which the
Agency is establishing exit criteria.
The Agency prefers to use only RfDs
and RfCs that have been evaluated and
verified by the RfD/RfC Workgroup as
the basis for setting regulatory levels.
However, for some constituents, the
Agency has not yet completed its
verification process; thus, RfDs and RfCs
under development are being used for
purposes of this proposal for those
constituents. If the final verified RfDs
and RfCs differ from the RfDs and RfCs
under development proposed in today's
notice, the Agency will adopt the new
(i.e., verified) values for the final rule
after noticing the data in the Federal
Register.
b. Carcinogens
The Agency proposes to use the oral
cancer slope factor and inhalation
cancer unit risk as the basis for
developing exit levels for carcinogenic
constituents unless the non-
carcinogenic effects occur at lower
levels. EPA's CRAVE Workgroup and
Office of Research and Development
have estimated the carcinogenic slope
factor (CSF) (i.e., the slope of the "dose-
response" curve) and inhalation unit
risks for humans exposed to low-dose
levels of carcinogens in the
environment. The slope factors indicate
the upper-bound confidence limit
estimate of excess cancer risk for
individuals experiencing a given
exposure over a 70-year lifetime. In
practice, a given dose multiplied by the
slope factor gives an upper estimate of
the lifetime risk to an individual of
developing cancer. By specifying a level
of lifetime risk (no matter how small),
one can also estimate the corresponding
dose using the slope factor.
EPA proposes to quantify on a weight-
of-evidence. basis, as described below.
EPA promulgated "Guidelines for
Carcinogen Risk Assessment" on
September 24,1986 (51 FR 33992),.
which defined a scheme to characterize
substances based on experimental data
and the kinds of responses induced by '
a suspect^carcinogen. These guidelines
specify the following five
classifications:
Group A—Human carcinogen (sufficient
evidence from epidemiologic studies)
Group B—Probable human carcinogen
Group B i—Limited evidence of
carcinogenicity in humans
Group 62—A combination of sufficient
evidence in animals and inadequate
or no evidence in humans
Group C—Possible human carcinogen
(limited evidence of carcinogenicity
in the absence of human data)
Group D—Not classifiable- as to human
carcinogenicity (inadequate human
and animal evidence of
carcinogenicity or no data available)
Group E—Evidence of non-
carcinogenicity for humans (no
evidence of carcinogenicity in at least
two adequate animal tests in different
species or in both adequate
epidemiologic and animal studies).
The weight-of-evidence basis was
used to eliminate Group D and B
constituents from further consideration
as carcinogens.
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Under each of the regulatory options
presented in today's proposal, the
Agency is using the same risk level for
Groups A, B, and C carcinogens. This
approach is consistent with the way
carcinogens were treated in the 1990
Toxicity Characteristic rule, hazardous
waste listing determinations, and the
dclisting program. The rationale for this
approach is mat while the
classifications indicate the type (human
or animal) and strength of the studies
available which reflects upon the
uncertainty about the carcinogenic
potential, the severity of the effect,
cancer, warrants equal treatment. It is
important to note that a few Group C
carcinogens do not have slope factors or
unit risks. In these cases the Agency
used the benchmark developed for the
non-cancer endpoint.
c. Consideration of MCLs
The Agency is proposing two
approaches for setting human health-
based levels for carcinogens and non-
carcinogens in routes of exposure
involving water ingestion. For the first
approach, the Agency is proposing to
use Maximum Contaminant Levels
(MCLs) promulgated under the Safe
Drinking Water Act (SDWA) of 1974, as
amended in 1986, as the human health-
based levels for the constituents for
which they have been established. In
general, MCLs for non-carcinogens are
derived from the Reference Doses
(RfDs), while MCLs for most
carcinogens are set as close to zero as
technically and economically feasible;
this normally corresponds to risk levels
that range from 10~4to 10 ~6. (Note that,
although the derivation of MCLs
considers feasibility of treatment,
analytic chemistry, and cost factors in
addition to health effects, it also
considers other routes of exposure. The
Agency's policy has been to use MCLs,
when available, in other similar
concentration-based programs.) For
those constituents which do not yet
have MCLs, the Agency is proposing to
use oral reference doses (RfDs) for non-
carcinogens and oral slope factors for
carcinogens as described above.
However, if new MCLs are finalized
under the SDWA prior to the
promulgation of today's rule, the
Agency proposes to substitute the new
MCLs for the RfDs and slope factor-
derived human health-based levels for
water ingestion presented in today's
notice.
For the second approach, the Agency
intends to propose to use only RfDs and
slope factors in deriving human health-
based levels for water ingestion. The
Agency requests comment on these two
approaches.
2. Ecological Benchmarks
Ecological benchmarks were
developed for a variety of ecological
receptors based on the availability of
data. Benchmarks were needed for
mammals, birds, plants, soil fauna, fish,
aquatic invertebrates, aquatic plants,
and benthos (sediment-dwelling
organisms). A much smaller number of
constituents have been evaluated by the
Agency for ecological effects than have
been for human health effects, as
discussed under V.A. In general,
measurement endpoints were selected:
(1) For consistency with the Agency's
Framework for Ecological Risk
Assessment (U.S. EPA 1992x), the Great
Lakes Initiative, and other ecological
efforts within the Agency, and (2)
relevance to the ecological receptor. As
discussed in "Section D—Risk
Assessment" the ecological assessment
focussed on inferring the sustainability
of populations and communities within
ecosystems. Therefore, benchmarks
were derived from measurement
endpoints (i.e., reproductive,
developmental, growth, survival, and
mortality) from which such inferences
could be made. Reproductive studies
(e.g., number of viable young per
female) were preferred over other
endpoints. For some constituents, acute
or mortality studies were used,
however, this occurred only for
developing benchmarks for fish, aquatic
invertebrates, and benthos where
protocol exists (AWQC development)
for using such data. The Agency seeks
comment on the measurement
endpoints selected for each ecological
receptor.
The lexicological benchmarks were
established using the more conservative
no effects level (or concentration) .
approach for ecological receptors as
compared to a 20% effects level. The
20% effects level is the lowest level for
ecological effects that can be detected in
field population analyses (Suter et al.,
1992). Although the 20% effects level
may indeed be the lower limit that
could be reliably confirmed in field
studies, this level reflects our current
analytical abilities and not necessarily
the ecological significance of the effects
level. The no effects approach was taken
because the ecological analysis infers
the sustainability of various populations
under the assumption that if a sufficient
number of populations within an
ecosystem is protected, then the
likelihood of adverse effects that are
causally related to the chemical stressor
will be reduced at the ecosystem level.
The Agency was concerned that if an
effects approach was taken, then the
assumption underlying the ecological
analysis would no longer be valid. The
Agency seeks comment on the approach
taken for setting toxicological
benchmarks.
Given the number and variety of
ecological receptors included in the
analysis (predatory birds to soil fauna)
as well as the variety of effects and
endpoints considered, the benchmark
development process required an
approach that was internally consistent
and acknowledged, at least
qualitatively, the uncertainty involved
in estimating ecological benchmarks.
The Agency, therefore, developed a
benchmark classification scheme to
incorporate both the relationship of the
benchmark to the entire toxicity data set
and the adequacy of the database used
to derive the benchmark. Three
classifications were established:
Adequate, provisional, and interim.
These classifications were developed on
a receptor group-specific basis (i.e., fish
and aquatic invertebrates, benthos,
mammals, birds, soil fauna, and
terrestrial plants) and represent a
weight-of-evidence designation for the
toxicological benchmark. In many
respects, this classification scheme is
similar in meaning to the human
carcinogen weight-of-evidence groups
and the difference between "verified"
values on IRIS and "unverified" values
in HEAST. The classifications relate to
the certainty assigned to a given
ecological benchmark. The benchmarks
were treated the same in the analysis
regardless of classification. See Section
4 in the "Technical Support Document
for the Hazardous Waste Identification
Rule: Risk Assessment for Human and
Ecological Receptors" for details on
each classification and how they were
used for each ecological receptor group.
The Agency seeks comment on the
classification developed for the analysis.
Below is a discussion of how
benchmarks were developed for each of
the receptor groups. For a detailed
discussion of each of their .
developments, see Section 4,
"Benchmarks," and Appendix B,
"Toxicological Profiles for Ecological
Receptors," of the "Technical Support
Document for the Hazardous Waste
Identification Rule:1 Risk Assessment for
Human and Ecological Receptors." The
Agency seeks comment on the overall
development of each of the ecological
benchmarks generated for this proposed
rule.
For populations of birds and
mammals, the overall approach used to
establish toxicological benchmarks was
similar to the methods used to establish
RfDs for humans as described in IRIS.
Each method uses a hierarchy for the
selection of toxicity data (e.g., no effects
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66354 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
levels are generally preferred to lowest
effects levels) and extrapolates from a
toxicity benchmark for the test species
to a toxicity benchmark for the desired
species. However, the procedures used
to develop benchmarks (i.e., RfDs) for
the protection for human health
establish an acceptable daily dose for all
individuals (including sensitive sub-
populations) while the development of
ecological benchmarks for this analysis
establish a level that will sustain the
reproductive fitness in a local
population. Consequently, benchmarks
for birds and mammals were established
using three key guidelines. First,
because the reproducing population was
selected as the assessment endpoint, the
benchmarks were developed from
measures of reproductive success or, if
unavailable, other effects that could
conceivably impair the maintenance of
the population.
Second, the taxon of the test species
was matched to the taxon of the wildlife
species to the greatest extent possible.
The evolutionary processes that result
in obvious differences in taxa (e.g.,
morphology) also result in differences in
the physiological processes that govern
chemical response. Moreover,
taxonomic similarities are generally
associated with similarities in feeding
habits, physiology, and chemical
sensitivity at the family classification
and, to a lesser extent, the order
classification. For example, herbivores
are generally more resistant to toxicants
than predators because they are exposed
to plant toxins, and the enzymatic
system that detoxifies plant toxins also
detoxifies pesticides and other organic
chemicals.
Third, a default safety factor of 10 was
adopted only for extrapolating from an
lowest-observed-effects level (LOEL) to
a no-effects level (NOEL). A ten-fold
safety factor was not applied to sub-
chronic studies since reproductive and
developmental toxicity studies are
frequently short-term. Even among
target organ toxicity studies, there are
many instances where sub-chronic
studies are actually more sensitive than
chronic studies carried out on the same
substance. Also, for mammals and birds,
differences in interspecies uncertainty
were indirectly addressed through the
use of the species-scaling equation
described in Section 4 of the "Technical
Support Document for the Hazardous
Waste Identification Rule: Risk
Assessment for Human and Ecological
Receptors." The Agency requests
comment on the use a safety factor of 10
when extrapolating from a LOEL to a
NOEL. The Agency also requests
comment on the use of a scaling
approach to address interspecies
uncertainty as described above.
Furthermore, the Agency seeks
comment on the inability of the Risk
Assessment to evaluate the inhalation
and dermal routes of exposure for birds
and mammals.
For the terrestrial plants, the approach
used to establish lexicological
benchmarks was adapted from the
Effects Range Low (ER-L) approach
developed by the National
Oceanographic and Atmospheric
Administration (NOAA). The NOAA
ER-L approach estimates a percentile of
the distribution of various toxic effects
thresholds. The measurement endpoints
were generally limited to growth and
yield parameters because (1) they are
the most common class of response
reported in phytotoxicity studies and,
therefore, will allow for benchmark
calculations for a large number of
constituents, and (2) they are
ecologically significant responses both
in terms of plant populations and, by
extension, the ability of producers to
support higher trophic levels. It should
be noted that these benchmarks were
limited to soil concentrations and do
not explicitly consider the adverse
impacts on plants from ambient
contaminant concentrations in the air.
Further details can be found in section
4.3.3 of the "Technical Support
Document for the Hazardous Waste
Identification Rule: Risk Assessment for
Human and Ecological Receptors." The
Agency solicits comment on the overall
approach taken to develop benchmarks
for the terrestrial plant community.
For the soil fauna, the toxicological
benchmarks were established based on
methods developed by the Dutch
National Institute of Public Health and
Environmental Protection (RIVM). The
RIVM approach estimates a confidence
interval containing the concentration at
which the no observed effects
concentration (NOEC) for p percent
(95th percentile was selected) of the
species within the community is not
exceeded 50% of the time. A minimum
data set was established in which key
structural and functional components of
the soil community (e.g., decomposer
and grazing organisms) encompassing
different sizes of organisms (i.e.,
microfauna, mesofauna, macrofauna)
were represented. As with the Ambient
Water Quality Criteria, measurement
endpoints included reproductive effects
as well as measures of growth, survival,
mortality. The Agency requests
comment on the use of the RIVM
methodology, and protecting 95 percent
of the community 50 percent of the
time. The Agency also requests
comment on its inability to fully
quantify the effect of soil characteristics
on toxicity of constituents to soil
organisms.
For populations of fish and aquatic
invertebrates (represented by daphnids),
a hierarchical approach was taken for
use of data sources in deriving
benchmarks. The first choice was final
chronic values (FCVs) from the
Sediment Quality Criteria effort by the
EPA Office of Water, followed by values
from the Great Lakes Initiative (GLI)
effort, and finally, the Ambient Water
Quality Criteria (AWQC). If these
benchmarks were not available, then a
benchmark was developed using AWQC
procedures or, if data were inadequate,
the GLI Tier II procedures for
establishing chronic values (termed
secondary chronic values—SCVs). The
AWQC ranked thir.d since many years
have passed since their establishment
and the SQC and GLI efforts re-
evaluated the toxicity data sets of
several of these. The Agency solicits
comment on the hierarchical approach
described above for deriving toxicity
benchmarks.
For aquatic plants, the approach used
to establish toxicological benchmarks
was adapted from the ER-L approach
developed by NOAA. The NOAA ER-L
approach estimates a percentile of the
distribution of various toxic effects
thresholds. However, due to the general
lack of toxicity data, the default ER-L
approach was used wherein the lowest
LOEC for either vascular plants or algae
was used. The Agency solicits comment
on the overall approach taken to
develop benchmarks for aquatic plants.
For the sediment organisms, the
approach used to establish toxicological
benchmarks for non-ionic, hydrophobic
organic chemicals was based on
sediment quality criteria methods for
non-ionic constituents. Two key
assumptions form the basis for the
proposed sediment quality criteria.
First, benthic species, defined as either
epibenthic or infaunal species, have a
similar toxicological sensitivity as water
column species. As a result, FCVs (or
SCVs) developed for the fish and
aquatic invertebrates can be used for the
benthic community. Second, pore water
and sediment carbon are assumed to be
in equilibrium and the concentrations
are related by a partition coefficient,
Koc. This assumption, described as
equilibrium partitioning (EqP), provides
the rationale for the equality of water-
only and sediment-exposure-effects
concentrations on a pore water basis:
The sediment-pore water equilibrium
system results in the same effects as a
water-only exposure. The Agency
requests comment on the use of this
approach in support of today's proposal.
In some cases, protecting these
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Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66355
ecological receptors represents the
critical pathway that limits the
projected exit level for management of
a waste stream outside of the Subtitle C
hazardous waste program. These
ecological receptors serve as the basis
for the proposed exit levels for 18
constituents, including 6 metals. To the
extent that contaminants from these
waste streams reach off site areas, the
Agency based its proposal on modeling
the ecological receptors on a
neighboring land area of 500 acres or an
adjacent stream (with a total length of
12 miles). This approach as currently
modeled, may only serve as an indicator
of a potential nearby threat to ecological
receptors (e.g., the soil fauna and plant
life), rather man serving as a measure or
indicator of a broader threat to the
environment. The Agency solicits
comment on the appropriateness and
relevance of these receptors as the basis
for exit levels under the HWIR program.
3. Sources of Data
a. Human
The two primary sources used to
identify human health benchmarks were
the Integrated Risk Information System
(IRIS) and the Health Effects Assessment
Summary Tables (HEAST). Both of these
sources were developed and are
maintained by the USEPA. For a few
constituents, other Agency sources such
as Carcinogen Assessment Group (GAG)
profiles, Health Effect Assessments
(HEAs), and Health Assessment
Documents (HADs) were used to fill
data gaps.
IRIS is the Agency's official repository
of Agency-wide consensus chronic
human health risk information. IRIS
evaluation are conducted by the
Agency's Work Group review process
that leads to internal Agency scientific
consensus regarding risk assessment
information on a chemical. This
information is recorded on IRIS and is
considered to be "Work Group
Verified."
The HEAST is prepared by EPA's
Office of Research and Development.
They contain risk assessment
information on chemicals that have
undergone a more limited review and
have the concurrence of individual
Agency program offices; each is
supported by an Agency reference. The
information has not, however, had
enough review to be recognized as
Agency-wide consensus information.
b. Ecological
A thorough literature review was
conducted to identify toxicological data
from laboratory and field studies for
each of the constituents of ecological
concern. The review included
secondary sources such as the Synoptic •
Review Series published by the U.S.
Fish and Wildlife Service, the Ambient
Water Quality Criteria documents, and
other Federal compendia of toxicity data
(e.g. HEAs, the Derivation of Proposed
Human Health and Wildlife ' , .
Bioaccumulation Factors for the Great
Lakes Initiative, Agency for Toxic
Substances and Disease Registry
documents, PHYTOTOX, GRIN,
TERRETOX, and AQUIRE). Toxicity
data on soil organisms were obtained for
several constituents from van de Meent
et al. (1990). In addition to AQUIRE, the
other primary data source for toxicity
data on aquatic plants were the
Toxicological Benchmarks for Screening
Potential Contaminants of Concern for
Effects on Aquatic Biota:1994 Revision
(Suter and Mabrey, 1994). On-line
literature searches were conducted to
identify primary sources of toxicity data
on constituents lacking sufficient data
in the secondary sources. Additional
studies were identified in conventional
literature reviews.
E. Risk Assessment
1. The Non-groundwater Risk
Assessment
a. Introduction
The risk assessment underlying
today's proposed rule is based upon a
comprehensive approach to evaluating
the movement of many different waste.
constituents from their waste
management units, through different
routes of exposure or pathways, to the
points where human and ecological
receptors are potentially exposed to
these constituents. This risk assessment
is being used in today's proposed rule
to determine which listed hazardous
wastes can be defined as "low-risk"
wastes, able to exit the Subtitle C system
and be managed in non-Subtitle C units.
The previous approach taken in the May
20,1992, proposed HWIR rule also
addressed the risks associated with, the
management of wastes containing
hazardous constituents with very
diverse physical and chemical
properties; however, only groundwater
ingestion exposures from landfill units
were evaluated. That approach led to a
concern by the Agency, as well as
commenters on the proposed rule, that
leachate from landfills contaminating
groundwater and subsequent
consumption of the contaminated
groundwater by humans may not be the
only exposure pathway important to
evaluate. Although the ingestion of
contaminated groundwater pathway
may be appropriate to propose exit
levels for some wastes and constituents,
it may be under-protective for others,
depending on the physical and chemical
properties of each waste constituent.
(For example, some constituents have a
high potential to bioaccumulate or
bioconcentrate in living organisms.
Pathways in which these constituents
come in contact with fish, grazing
livestock, wildlife, or edible plants
would be important to evaluate.) In
addition, over the past 14 years of
implementing the RCRA program, the
Agency has learned more about
potential routes of release to the
environment from various management
practices.
Therefore, for today's proposal the
Agency undertook an extensive risk
assessment that examines numerous
exposure pathways, rather than just the
groundwater ingestion pathway, hi
selecting the exposure pathways,
previous rulemakings were used as a
guide, as well as other special studies by
the Agency that implement analyses
examining numerous pathways. (Tables
A-l and A-2 contain the human and
ecological pathways, respectively,
evaluated in the assessment, and are
presented in appendix A to today's
preamble.) With regard to waste
management units considered in the
assessment/it is important to note that
because today's proposal establishes
criteria for waste to exit the Subtitle C
system, the assessment evaluated
exposures associated with managing
wastes in non-Subtitle C units. The
human and ecological receptors
considered in the assessment were
selected to represent a range of
behaviors, activities, dietary habits, and
trophic levels that influence exposure
levels. .
The risk assessment supporting this
proposal is currently undergoing review
by the Science Advisory Board and
EPA's Office of Research and
Development. As a result of these
reviews, and of comments received
during the public comment period, it is
likely that EPA would make changes to
the risk assessment or other parts of the
rule. Topics on which the Agency has
received informal comment include the
use of ecological benchmarks for
regulation and the overland transport of
waste constituents. The Agency, to the
extent consistent with the schedule
negotiated in the consent decree for this
rulemaking, would publish a
supplemental notice proposing any
significant changes before finalizing the
rule.
b. How the Assessment is Structured
The non-'groundwater assessment
acknowledges that not all human and
ecological pathways arise from each
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66356 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
source; for example, movement of
particles from an active surface ,
impoundment is not expected to occur.
To account for this, the assessment
matched the environmental transport
pathways with both the releases from
various types of waste management
units and the various receptors for the
nearly 200 constituents examined. All
constituents were assessed in all
pathways deemed plausible for a given
waste management unit, if the data
permitted. Tables A—3, A-4, and A-5 of
appendix A show the pathways assessed
for each waste management unit, human
receptors assessed for each pathway,
and ecological receptors assessed for
each pathway, respectively. The
assessment estimated the constituent-
specific concentrations in a waste at the
management unit that could be expected
to result in an acceptable exposure for •
a human or ecological receptor
(determined through using the toxicity
benchmarks discussed in section V.B.),
taking into account the various
pathways by which the constituent may
move through the environment from the
waste management unit to the receptor.
The waste management units
considered in the assessment are not all-
inclusive but were selected to reflect
those that might be commonly
associated with the management of
exited hazardous wastes (from
wastewaters to nonwastewaters) in non-
Subtitle C waste management units.
These units were identified as
commonly used in the management of
solid wastes in the 1988 Report to
Congress entitled Solid Waste Disposal
in the United States Report. The Agency
believes that risks posed by other types
of management of these exited wastes
will be no greater than those from the
units assessed.
There is a high degree of variability in
the physical and chemical properties of
the approximately 200 constituents
evaluated. An understanding of those
properties and how they interact with
the physical and chemical properties
that control persistence and mobility in
the environment is an essential element
of the assessment. The management
units could potentially be located in the
range of environments that exist across
the United States. These environments
have differing characteristics (e.g.,
meteorological conditions, soil type) ,
that are more conducive for the
movement of certain constituents in
certain pathways than others. For
example, an environment with a high
precipitation and high organic soil
content may result in significant
exposures to fishers by constituents that
readily adsorb.to soils (i.e., have a high
log Kow) through erosion of ;
contaminated soil and uptake in the
food chain. For other pathways,
however, an environment with these
characteristics may result in relatively
low exposures. The assessment was
designed to determine what conditions
would need to exist to cause higher
exposures for each pathway rather than
developing a scenario and determining
all the types of exposures and receptors
for that scenario. By determining the
appropriate conditions for which higher
exposures from a given pathway will
. occur, the Agency believes that
environments where the conditions are
not as likely for a constituent to move
through a pathway are protected.
The assessment was structured using
a deterministic approach; A
deterministic approach uses a single,
point estimate of the value of each input
or parameter and calculates a single
result based on those point estimates.
The assessment used the best data
available to select typical (i.e.,
approximately 50th percentile) and
high-end (i.e., approximately 90th
percentile) values for each parameter or
parameter group as discussed in Section
E.2. below. Sometimes full distributions
were available but, more commonly,
ranges of values or point values were
available with no description of
distributions-or variability. If there was
not a sufficient distribution for the
parameter, best professional judgement
was used in determining typical and
high-end values (which sometimes
would be the maximum).
The assessment is constructed as a set
of calculations that begin with an
acceptable exposure level for a
constituent at a receptor, and back-
calculates to a concentration in a waste
in a management unit that corresponds
to the acceptable exposure level. For the
human receptors, the assessment was
designed to determine constituent
concentrations in waste for each waste
management unit that would
correspond to protecting receptors at the
high-end of exposure (i.e., above the
90th percentile of each of the receptor
populations and types of exposures
being assessed). The Agency estimated
waste concentrations corresponding to
the high-end exposure by identifying
four critical or sensitive parameters in
the source/pathway/receptor equations
and using high-end input values for
those parameters and using central
tendency values for the remaining
parameters. The Agency also estimated
central tendency (approximately the
50th percentile) and bounding estimates
(worst-case) of constituent
concentrations in waste for each of the
receptor populations and types of
exposures being assessed. For ecological
receptors, the approximate percentile
level of protection is difficult to discern.
The Agency believes the ecological
analysis is conservative with respect to
the overall assessment endpoint (e.g.,
sustainability of the reproducing
populations) because.of the way the
source, fate and transport parameters are
set, the dietary habits assumed, and how
the toxicity benchmarks are developed.
However, the degree to which this
conservativeness transfers to ecosystems
is not known.
The steps of the assessment which
provide estimates of acceptable
constituent-specific concentrations in ,
waste include the following:
Step 1—Specify acceptable risk levels
for each constituent and each receptor.
See Section V.B. in today's preamble for
a discussion of how benchmarks are set
for both human and ecological
receptors.
Step 2—Specify the exposure
medium. Using the toxicity benchmarks
as a starting point and the exposure
equations, the assessment back-
calculates the concentration of
contaminant in the medium (e.g., beef,
milk, plant, air, water, soil) that
corresponds to the "acceptable"
exposure level. The exposure equations
include a quantitative description of
how a receptor comes into contact with
the contaminant and how much, the
receptor takes in through specific
mechanisms (e.g., ingestion,inhalation,
dermal adsorption) over some specified
period of time. Thus, for the subsistence
farmer eating contaminated beef, the
exposure specifies the amount of beef
eaten on a daily basis, the period, of time
over which the contaminated beef is
eaten, and descriptions for the
individual such as body weight and
lifetime. For this example, the
concentration in the beef is what is
back-calculated.
Step 3—Calculate the point of release
concentration from the exposure
concentration. Based on the back-
calculated concentration in the
exposure medium (from Step 2), the
concentration in the medium to which
the contaminant is released to the
environment (i.e., air, soil, groundwater)
for each pathway/receptor was modeled.
The end result of this calculation is a
medium concentration at the point of
release from the waste management
unit.
Step 4^Calculate the concentration
in the waste that corresponds to the
medium concentration at the point of
release. This step depends on the
characteristics (e.g., area, cover
practices, waste consistency) of the
waste management unit. -
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The output of the assessment is a
range of constituent concentrations,
reflecting the range of pathway-receptor
combinations considered for each waste
management unit. The lowest
concentration (per constituent) of this
range represents the highest exposure
pathway-receptor combination for that
waste management unit.
c. How Uncertainty is Addressed
Any analysis of the magnitude used in
this rule-making will have uncertainty
associated with the outputs generated.
The'uncertainty can be associated with
the models or equations used and the
data relied on for the model parameters.
In addition, policy assumptions, such as
waste management units assessed and
receptors assessed, may also affect the
degree of representativeness of the
assessment. In order to be consistent
with Agency policy on the
characterization of risk, stochastic and
deterministic approaches were
considered. A stochastic approach, such
as Monte Carlo analysis, which
produces a distribution of constituent
concentrations, was initially considered
duo to the tremendous interest in, and
use of, these techniques in risk
assessment. However, after evaluation of
the models and data available for use,
the Agency decided to use a
deterministic approach for the non-
groundwater assessment.
The Agency's detenninistig approach
used for this assessment, like most such
approaches, uses point values In all
calculations and produced point
estimates of constituent concentrations
for waste in each management unit-
exposure pathway-receptor
combination. However, in selecting and
developing point values for parameters,
EPA considered all available data.
Wherever possible, the Agency
developed both a central-tendency and
high-end value for each parameter used
in the assessment. This was not possible
in all cases because some parameters
were a property, such as density of
water, and because some values were
fixed by Agency-wide policy decisions.
(For example, EPA used standard
Agency-wide human toxicity
benchmarks and body weights.) EPA
then calculated constituent
concentrations based on a mixture of
central-tendency and high-end values.
EPA believes that the deterministic
approach described above (based on
identifying critical parameters and using
higher-end values only for those
parameters and central-tendency values
for the other parameters) allowed it to
derive constituent concentrations hi
waste for each waste management unit
that are reasonably protective across a
range of conditions and for a range of
receptors. EPA also believes that this
approach is consistent with EPA's risk
assessment policy.
EPA further believes that the
approach chosen allows both the
Agency and the public to determine
more easily which parameters played
the most critical roles in determining
the constituent concentrations in waste
for each waste management unit. This
furthers general understanding of the
assessment and helps commenters
effectively target their resources for
reviewing what EPA is proposing. It has
also helped EPA target its own data
collection and input selection efforts. It
is often more difficult to identify critical
parameters in a stochastic assessment
because of the greater number of
iterations and because results are
reported as probability distributions.
This is particularly true for an analysis
with a large number of parameters such
as the assessment used for this proposed
rule.
EPA notes that stochastic approaches
are also consistent with Agency risk
assessment policy. In fact, EPA applied
a stochastic "Monte Carlo" approach to
the separate analysis of dilution and
attenuation of groundwater performed
for this proposal. That analysis,
however, has been under development
for many years and EPA is more familiar
with the underlying data and the
relationships between various
parameters. In addition, the public has
had a chance to comment on aspects of
that analysis in previous rule-makings.
EPA was more comfortable applying a
stochastic analysis for the groundwater
analysis than a stochastic approach to
the non-grpundwater analysis.
EPA believes that it is not necessary
to resolve all issues relating to the
relative merits of the two approaches or
to determine which approach would be
ideal for each of the assessments
described above. Rather, the debate
should focus on whether the approaches
chosen allowed EPA to reach reasonable
regulatory decisions.
The Agency solicits comment on the
use of a deterministic approach as
described above. Specifically, the
Agency seeks comment on whether the
approach proposed is a reasonable
approach for setting protective levels
across a set of types of management
units and exposure pathways.
d. Linkage of the Non-groundwater Risk
Assessment to the Groundwater Risk
Assessment
In the non-groundwater risk
assessment, the pathways involving
potentially contaminated groundwater
(e.g., bathing) are back-calculated from
the receptor to the wellhead (i.e., the
assessment provides constituent
concentrations in the groundwater at the
well). In order to determine the
concentration of a constituent in
leachate coming from a waste
management unit that would result in
the estimated constituent concentration
at the water well, the Agency used a
separate groundwater fate and transport
risk analysis. That analysis is described
in detail in Section D.8. elsewhere in
today's proposal. The well
concentrations estimated .from the
pathways involving bathing are used as
input to the groundwater fate and
transport modeling from which a
leachate concentration is determined.
e. Risk Targets Used
As previously discussed in Section
V.B. of today's proposed rule, the
Agency used existing toxicity
benchmarks when available. However,
many ecological benchmarks were
developed for this rule-making, as
discussed in Section V.B. of today's
proposed rule. As described in that
section, the Agency used a cancer risk
target of 1 x 10 ~6, and a hazard quotient
equal to 1 for non-carcinogens. For
ecological benchmarks, a hazard
quotient equal to 1 was used. The
Agency solicits comment on the risk
targets being used for today's proposed
rule.
2. Detailed Overview of the Non-
groundwater Risk Analysis
The assessment can be broken down
into six components: Constituents;
toxicity benchmarks; receptors;
exposure; fate and transport; and waste
management units. Each of these
components is discussed in turn below,
except the constituents and toxicity
benchmarks which were discussed
earlier in section V.A and V.B. It is
important to recognize that the
assessment was not able to evaluate all
constituents in all receptor-pathway-
waste management unit combinations
because of data gaps in either toxicity or
chemical properties, or inadequate
methodologies. Many of these gaps have
been identified in different sections of
the Technical Support Document for the
Hazardous Waste Identification Rule:
Risk Assessment for Human and
Ecological Receptors" (denoted
"Uncertainties and Issues of Concern").
The Agency requests additional data or
other information that would assist in
filling these gaps.
a. Waste Management Units
The manner in which constituents are
released to environmental media and
the relative quantity released to each
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medium will affect the pathways of
most concern for a particular
constituent. The pathway presenting the
highest risk to human or ecological'
receptors is not always easily
determined because of the complex
interactions of the waste management
unit and its types of releases, the
physical and chemical properties of the
constituent, and the properties that
control mobility and persistence in a
particular environmental medium. For
some constituents, the management
practice will determine which exposure
pathway is of most concern. For
example, benzene tends to migrate to
both aur and groundwater. Upon
examining the risks from exposure to
these two media arising from releases
from a quiescent surface impoundment,
the groundwater ingestion pathway may
pose the highest risks. But, when
examining the risks from these two
media for releases from an aerated tank,
the air inhalation pathway may pose the
higher risks. Further, the air inhalation
risks may even be higher than
groundwater ingestion risks from the
quiescent surface impoundment.
Therefore, and as stated earlier, the
selection of non-Subtitle C waste
management units examined in the
assessment attempted to reflect both the
influence of the type of unit on
pathways and those that might be
commonly associated with the
management of exited hazardous wastes
in non-Subtitle C waste management
units. Again, the Agency believes that
risks posed by other types of
management of these exited wastes will
be no greater than those from the units •
assessed. The management units
examined include the following:
• Aerated treatment tanks. Relative to
all other types of management, aerated
tanks containing wastewaters can
potentially have the most significant
releases of volatile organics to air.
• Quiescent surface impoundments.
This type of unit containing
wastewaters also can potentially result
in significant releases of volatile organic
constituents to air. These units also
have a potential to affect surface water
bodies if the unit is not well maintained
or constructed. The sludges generated,
which may contain high concentrations
of metals and hydrophobic constituents,
may impact groundwater. (As discussed
above, the groundwater fate and
transport analysis was conducted in a
separate analysis.)
• Land application. This type of unit,
when used for non-wastewaters can
potentially have significant releases of
certain constituents to nearby land and
surface water bodies through erosion
and runoff, particularly if run-on and
run-off control measures are not
practiced. In addition, significant
releases of volatile organics constituents
to air are possible. Further, after the unit
is closed, significant on-site exposures
to some persistent and relatively
immobile constituents may occur as ,
well as continued long-term releases to
the nearby land and surface water
bodies. The Agency believes such units
will pose higher exposures relative to
landfills in all pathways except those
arising from groundwater. Therefore, the
non-groundwater assessment did not
examine landfills, but they were
examined in the groundwater fate and
transport analysis.
• Ash monofill. This type of unit
used for ash disposal can potentially
have significant releases of particulates
to air which may be inhaled or may
deposit on land and plants, and result
in exposure through food and soil
ingestion.
• Wastepiles. This type of unit used
for nonwastewaters can have significant
releases of particulates to air as well as
significant releases of particulates
through erosion and runoff.
Each of the pathways that evaluates a
receptor using contaminated
groundwater other than as a source of
drinking water (i.e., bathing) are back-
calculated to a concentration in a
drinking water well. The pathways are
applicable to all of the waste
management units modeled (except
tanks). All of the waste management
unit and chemical-specific portions of
the groundwater fate and transport
analysis and subsequent estimated
leachate concentrations are contained in
the Agency's separate groundwater fate
and transport analysis (see Section E.3
below).
One exception to the above discussion
of the types of waste management units
evaluated involves the combustion of
wastes. Although the Agency attempted
to include this type of management in
the assessment, it became clear .that the
emissions from combustion are not
easily predicted from the waste inputs
to the units. The combustion process
both destroys and creates constituents.
Although destruction of constituents
can be predicted based on certain
operating characteristics of combustion
units, the creation of other constituents,
referred to as products of incomplete
combustion (PICs), is not easy to
predict. It may be possible to make such
predictions for a specific waste and a
specific combustion unit; however, the
extensive data (e.g., on the variety of
combustion units, waste types,
constituent combinations) needed for
the assessment used in this rulemaking
relating wastes with emissions are not
available. Therefore, acceptable
constituent levels in waste going to a
combustion unit could not be
established. However, the Agency is
developing emission standards for
various types of combustion units and
those emission standards may be a more
appropriate vehicle for addressing
combustion.
In addition, the assessment does not
address accidental or catastrophic
releases, such as transportation
accidents or tank failures. The Agency
determined that, although such releases
are possible, they are of low probability
and non-routine and, therefore, are not
appropriate for developing exit criteria
that apply to all wastes.
The Agency has identified several
specific areas giving rise to uncertainty
in the characterization of the waste
management units and for which the
Agency seeks comment:
(1) Use of Subtitle D Survey.
• The Agency relied upon data from
a 1987 survey of Subtitle D facilities to
characterize waste management units.
That survey, used in the 1988 Report to
Congress on Solid Waste Disposal in the
United States, was designed primarily to
collect estimates of the following
parameters:
• Number of establishments that
manage Subtitle D wastes on site;
• Number of establishments that
manage Subtitle D wastes on site in land
application units, wastepiles, surface
impoundments, or landfills;
• Number of land application units,
wastepiles, surface impoundments, or
landfills used to manage Subtitle D
wastes;
• Amount of Subtitle D wastes
managed on site in land application
units, wastepiles, surface
impoundments, or landfills.
In addition to these parameters, data
were also collected for some other
parameters, such as the area of the waste
management units. Although the survey
was not designed to collect accurate
estimates for these other parameters, it
is the most comprehensive date
available to characterize these other
parameters. One difficulty encountered
in using these data is that the survey
requested information on total area or
waste quantity for all of each type of
units at a facility. The total area or waste
quantity was divided by the number of
each type of unit at the facility (number
of each unit being one of the primary
parameters the survey was designed to
estimate) to estimate average unit area.
Further, it is not certain how well the
on-site units (which are used routinely
for wastes generated on-site) reflect the
characteristics of off-site units.
Uncertainty related to the
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representativeness of the data is
important because exited wastes could
be managed in units off-site as well as
on-slte. The Agency seeks comment on
the use of the Subtitle D survey to
characterize the waste management
units.
In evaluating the waste management
unit components of the risk assessment,
the Agency made certain assumptions
when data were not available or were
incomplete. A description of the waste
management unit parameters for which
there was little to no data is described
below. The rationale behind these
assumptions is presented (e.g., results of
any sensitivity analyses, references to
other work, etc.). The Agency requests
comment on the specific issues raised
for each management unit.
(2) Fate and Transport
Fate processes, particularly
biodegradation and hydrolysis, were
accounted for only in the land
application unit since that unit had
wastes applied intermittently and that
unit was being examined for on-site
risks after closure (assuming human
occupation of the site begins 10 years
after closure occurs). Because waste is
continuously applied to the other waste
management units, biodegradation and
hydrolysis were presumed to have
minimal influence on the subsequent
availability of constituents to the above
ground pathways. The Agency requests
comment on not considering
biodegradation and hydrolysis in waste
management units other than the land
application unit. The Agency also
requests comment on the
appropriateness of the data and methods
used to account for the fate and
transport of constituents in waste
management units, with particular
emphasis on data and methods of
determining biodegradation and
hydrolysis of constituents in land
application units.
(3) Ash Monofill
(i) Particle Size Distribution for Air
Dispersion Modeling
A size distribution of ash particles
that become airborne from an ash
monofill was not available. Therefore, a
sensitivity analysis was performed to
assess the importance of the particle
size distribution in the calculation of air
concentrations and deposition rates.
Different distributions were modeled
reflecting a variety of assumptions for
particle size distributions between
PMlO and PM30 classes. The greatest
deviation among the modeled
conditions in the estimated air
concentration of PMlO was 12 percent;
for the estimated deposition rate for
PM30 the greatest deviation was 59
percent. Given the uncertainties and
variabilities inherent in the assessment,
these variations were considered minor,
therefore, the Agency assumed an equal
distribution of particle sizes between
the two size classes used in the
assessment.
(ii) Monofill Characterization
Because limited data were available to
characterize hazardous waste ash
monofills, data from municipal waste
ash monofills were used. However,
because ash generation rates for
municipal waste incinerators ere more
than 100 times greater than ash
generation rates for hazardous waste
incinerators and reuse-as-fuel
combustors resulting in significantly
larger municipal monofills, EPA
calculated an ash monofill volume for
this analysis based on generation rates
reported in the 1988 National Survey of
Hazardous Waste Treatment, Storage,
Disposal, and Recycling Facilities,
assumed bulk density of the ash, and
assumed lifetime of the monofill. The
Agency is not certain that hazardous
waste monofills should be sized in the
same manner as municipal waste
monofills. The Agency also assumed
that each waste monofill would accept
ash from only a single combustor.
Accepting wastes from more than one
combustor may underestimate monofill
size. ' .
(iii) Vehicle Traffic
The estimates of number of ash trucks
per day are dependent on the size of
truck. Limited data were available on
the sizes of trucks hauling ash. These
data were used to characterize a range
of truck sizes. The truck sizes .may
either under- or overestimate the size of
trucks actually used at hazardous waste
ash monofills depending oh the ,
representativeness of municipal waste
ash truck sizes.
No data were available on other
vehicular traffic; therefore, these values
were estimated, introducing additional
uncertainty into the overall amount of
traffic at the ash monofill.
(iv) Emission Equations for Ash Blown
From Trucks and During Spreading and
Compacting
The emission equation used for ash
blown from trucks was developed for
windblown emissions from storage
piles. This was adapted to trucks by
using the truck speed to estimate
frequency of wind greater than 5.4 m/s.
Because this equation was not derived
for windblown emissions from moving
trucks, the results of its application to
such emissions are uncertain. It may
over- or underestimate actual emissions
of particulates blown from trucks.
Similarly, the emission equation used
for spreading and compacting was
developed for agricultural tilling.
Agricultural tilling was thought to
approximate the process of spreading
and compacting; however, the use of
this equation may under- or
overestimate emissions due to spreading
and compacting.
(4) Land Application Unit
(i) Particle Size Distribution for Air
Dispersion Modeling
A size distribution of soil particles
that become airborne was not available.
The same assumption was made for soil
particles as was done for ash particles
when modelling the monofill (see
above). As described above for ash
particles, the Agency assumed an equal
distribution of particle sizes between
the two size classes.
(ii) Area of Land Application Unit
Relative to Agricultural Field
The assessment examined the impact
of subsistence farming on the land
application unit beginning 10 years after
closure. Based on the distribution of
sizes for land application units and
agricultural fields, the Agency selected
a combination of fields such that the
central tendency land application unit
(61,000 m2) is smaller in area than the
central tendency agricultural field
(2,000,000 m2). The significantly larger
size of the agricultural field suggests
that the model may inappropriately
average the constituent concentration
over the agricultural field. However, the
Agency does not believe this to be a
significant impact on the analysis
because: (1) The area of the agricultural
field is not an explicit input to the
model; (2) the size of the land
application unit is large enough to
support a subsistence farmer; and (3)
this pathway is driven by the
assumptions for the high-end analysis.
The Agency requests comment on the
relationship between the land
application unit and the agricultural
field.
(iii) Application Rate
The waste application rate is an
important parameter in determining the
constituent's soil concentration after
application. In practice, this rate is a
function of the characteristics of the
waste being applied, the characteristics
of the receiving soil, the environmental
conditions, and the purposes for which
the waste is being applied. Information
from the Subtitle D survey was used to
calculate the rates, since those rates
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were not expressly requested in the
survey. The rates were calculated from
the area receiving the wastes and the
waste quantity applied. This introduces
uncertainty for it combines rates
applicable to both treatment of wastes
and rates for specific uses (e.g., farming,
mine reclamation). To account for the
potential of having application rates be
much too high for the site they are being
applied to, the data on receiving area
and waste quantity applied were linked.
(iv) Waste Characteristics
Limited data were available on the
characteristics of wastes being land
applied. As a result, soil values for most
parameters (e.g., hydraulic conductivity,
moisture retention index) were used to
characterize nonwastewaters. It is not
known to what extent these soil values
differ from the waste properties.
(v) Depth of Contamination
Depth of contamination affects the
amount of constituent available for
exposure. For the non-groundwater
pathways, only constituents at the soil
surface were assumed available for each
exposure pathway. The Agency selected
tilling depth as the depth of
contamination available to the non-
groundwater pathways as over time, the
depth of the waste layer would increase
and a portion of the mass of waste
would move out of the zone available
for the surface pathways. The model
kept the depth of contaminated soil
constant that was available for the
surface pathways. The Agency
recognizes that the use of the tilling
depth may underestimate the depth of
contamination in some cases and
overestimate it in others. Thus, the
Agency requests comment on the use of
tilling depth as a surrogate for depth of
contamination.
(vi) Partitioning
Releases from the land application
unit were partitioned among
volatilization, evaporative losses,
hydrolysis, erosion, runoff, and
leaching. Periodic application of waste
was factored into the partitioning model
during the active life of the unit.
Biodegradation was factored in during
both the active life and closed period.
The finite source Jury model was used
to estimate volatilization emissions. The
Jury model, which models the
convection of constituents caused by the
flux of water in soil, was used for
evaporative losses. Runoff and leaching
losses were calculated using the soil-
water partition coefficient (Kd) to
determine constituent concentration in
the soil water and multiplying that by
the land application unit area and
runoff rate for run-off losses or recharge
rate for leaching losses. (See Technical
Support Document for the Hazardous
Waste Identification Rule: Risk
Assessment for Human and Ecological
Receptors, Section 7, Land Application
for full description.)
(5) Waste Pile
(i) Waste Pile Height
No data were available on this
parameter; therefore, the value is an
estimate based on heights attainable by
a front-end loader. This parameter is '
important in the air dispersion
modeling, which is sensitive to the
height of the pile. The Agency requests
suggestions for alternatives to
determining waste pile height and any
data which would support those
determinations.
(ii) Particle Size Distribution for Air
Dispersion Modeling
The same sensitivity analysis and
assumptions discussed above for ash
monofills were used for waste piles.
Given that the air dispersion analysis is
not very sensitive to particle size
distribution, the simple assumption
described above was believed to be an
adequate approximation for the
assessment.
(iii) Waste Characteristics
Limited data were available on the
characteristics of wastes in waste piles.
As a result, soil values for most
parameters (e.g., hydraulic conductivity,
moisture retention index) were used to
characterize the nonwastewaters
disposed in piles. It is not known to
what extent these soil values differ from
the waste properties. The soil values,
however, were not used for the ash
waste pile. The ash disposed in the piles
had the same properties as that disposed
of in a monofill.
(iv) Vehicle Traffic
The estimates of number of trucks per
day are dependent on the size of truck
and waste quantity. Limited data were
available on truck sizes. These data
were used to characterize a range of
truck sizes. These truck sizes may either
under- or overestimate the size of trucks
actually used around waste piles.
(v) Emission Equation for Ash Blown
from Trucks
As described in the section above on
ash monofills, the emission equation
used for ash blown from trucks was
developed for windblown emissions
from waste piles. It may over- or
underestimate actual emissions of
particulates blown from trucks.
(6) Surface Impoundment
(i) Two-Phase Sludge Formation Model
The two-phase sludge formation
model simplifies the solids
concentration gradient in a surface
impoundment into two distinct and
homogeneous layers, a liquid layer with
the same average solids content as the
inflow and a sediment or sludge layer
with a much higher solids
concentration.
(ii) Dilution of Waste During a Spill
Overflows or breaches associated with
surface impoundments are a waste
release examined in the assessment. The
algorithm used for spills does not
account for dilution of the wastewater
caused by excess run-on. Such run-on is
presumably relatively uncontaminated;
thus the spill volume, consisting partly
of contaminated wastewater from the
impoundment and partly of
uncontaminated run-on would have a
lower concentration than the
wastewater in the impoundment. By
using the concentration in the
impoundment, the mass of contaminant
released to surface water is
overestimated. This effect could be
considerable for the central tendency
impoundment, as the quantity of run-on
is significant compared to the capacity
of the central tendency impoundment.
However, to determine the extent of
such dilution, the degree to which such
run-on becomes mixed with the
wastewater would need to be estimated.
No model has been found to assist in
this estimation.
(7) Tank
(i) Unit characterization
Limited data were available on
Subtitle D tanks. The assessment used
the profiles (specifies design and
operating parameters) for uncovered
aerated treatment tanks developed in
the Hazardous Waste TSDF—
Background Information for Proposed
RCRA Air Emission Standards (TSDF—
BID, U.S. EPA, 1991)
(ii) Volatilization
The Agency used the well-mixed flow
model. This model assumes that the
contents of the system are well mixed
and that the equilibrium concentration
in the system is equal to the effluent
concentration. The equilibrium
concentration is the average
concentration throughout the unit and
the driving force for volatile emissions.
(8) Combustors
For the reasons stated below, EPA did
not modelled a combustion unit in the
risk analysis for this regulation. EPA,
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however, asks for comments on that
decision.
hi initial analyses (see Multipathway
Analysis Background Document
available through the docket), EPA
modeled potential risks from several
types of combustion units, using
engineering judgment to make a best
estimate for destruction and removal
efficiencies for non-hazardous waste
combustors. Early comments suggested
that the assumptions might have
overstated or understated the estimated
risks by not reflecting actual practice in
industrial boilers or other likely
combustion facilities not regulated by
Subtitle C. However, initial comparisons
indicated that the combustion risk
estimates back-calculated to the
combustion unit were not often the most
significant risk and, therefore, would
not be the basis for the limiting exit
criteria.
EPA also recognized that there are
many issues related to organics that are
produced during the combustion
process, but are not necessarily
originally in the waste. The amount and
type of these "products of incomplete
combustion" are generally believed to
be dependent on a number of aspects of
the design and operation of a facility,
and not easily related to the
composition of the wastes fed into the
combustion unit. For purposes of this
proposal, EPA decided that because of
the high degree of uncertainty
associated with developing waste
concentrations from combustion units,
it was not appropriate to use risks from
combustion as a factor in deciding what
wastes remain under the hazardous
waste regulations. Rather, EPA believes
there are more appropriate ways to
regulate emissions from combustion
units through various regulatory
authorities, including regulation of a
range of units under the Clean Air Act.
EPA, however, asks comment on the
appropriateness of this approach. In
particular, there may be some
constituents (e.g., certain metals that are
difficult to capture in pollution control
equipment) where a better correlation
exists between waste input and
potential risk from combustor emissions
than for organics that are in the waste
and also created as PICs during the
combustion process.
b. Fate and Transport
(1) Pathways
In selecting environmental fate and
transport pathways to include in the
assessment, EPA used as a guide
previous rulemakings and other special
studies by the Agency that examine
numerous pathways. For example, the
Agency has used similar risk assessment
methodologies in several recent rules
including: Wastes from Wood Surface
Protection, Final Rule (59 FR 458,
January 4,1994); Standards for Use or
Disposal of Sewage Sludge, Final Rule
(58 FR 32, February 19,1993);
Corrective Action Management Units,
Final Rule (58 FR 29, February 16,
1993); and rulemaking efforts on the
Pulp and Paper Industry (56 FR 21802,
May 10,1991 and 58 FR 66078,
December 17,1993).
The sewage sludge and pulp and
paper rulemakings in particular
examined both human and ecological
risk. Other rulemakings under
development within the Office of Solid
Waste also use non-groundwater risk
assessment methodologies including
various hazardous waste listing
determinations and the dioxin emission
rules for hazardous waste combustion
units. Most of these assessments rely on
several Agency guidance documents
issued in recent years. In January 1990,
the Agency issued an interim report,
Methodology for Assessing Health Risks
Associated with Indirect Exposure to
Combustor Emissions (EPA/600/6-90/
003 and referred to as the Indirect
Exposure Document). This document
served as the basis for further
development of non-groundwater
pathway assessments by the Agency. In
November 1993, the Agency issued an
Addendum to the Indirect Exposure
Document that updated and revised
portions of the methodology presented
in the Indirect Exposure document. In
April 1994, OSW issued a draft
implementation guidance entitled
Implementation Guidance for
Conducting Indirect Exposure Analysis
at RCRA Combustion Units. In June
1994, the Agency released a review draft
of Estimating Exposure to Dioxin-Like
Compounds: Volumes I-III (EPA/600/6-
88/005C), which presents an extensive
and expanded version of the Agency's
previous multiple pathway exposure
assessments. Finally on November 16,
1994, the Agency issued Draft Soil
Screening Guidance (59 FR 59225),
which presents a multiple pathway
assessment using air, groundwater, and
soil pathways for soil screening levels at
Superfund sites. The risk assessment
presented relies on the methodologies
presented in these Agency guidance
documents to maintain consistency with
previous Agency efforts.
Based on these efforts by the Agency
in conducting non-groundwater
pathway assessments, comments by
reviewers on previous draft versions of
the risk assessment, and some screening
analyses to identify pathways that are
either very similar or unimportant
compared to other pathways, the
Agency selected the human and
ecological exposure pathways presented
in Table A—1 (human exposure
pathways) of appendix A and Table A—
2 (ecological exposure pathway) of
appendix A. These exposure pathways
are described in greater detail in the
Technical Support Document for the
Hazardous Waste Identification Rule:
Risk Assessment for Human and
Ecological Receptors.
Tables Arl and A-2 presents four
columns: column 1 (exposure media),
identifies the medium, such as air or
soil, to which the receptor is exposed;
column 2 (route of exposure), identifies
the route, such as inhalation or
ingestion, by which a receptor is
exposed to the exposure medium;
column 3 (type of fate and transport),
classifies the pathway by the primary
mode of fate and transport of the
contaminant to the exposure medium,
including direct air, air deposition, air
diffusion, groundwater, overland, and
soil; and column 4 (exposure scenario),
identifies the compartments in the
pathway (e.g., source to air to humans),
and describes the exposure scenario
(e.g., inhalation of volatiles).
The fate and transport pathways
examined can be grouped into six types
of initial release and movement away
from a waste management unit, as
follows:
• Direct air pathways—air emissions
of volatiles and respirable (PMio)
particulates;
• Air deposition pathways—air
emissions of particulates that deposit on
soil or plant surfaces;
• Air diffusion pathways—air
emissions that, while in the vapor
phase, diffuse directly into surface
water or plants;
• Groundwater—groundwater
releases (These are the pathways that
link to the separate groundwater fate
and transport analysis that then links to
the waste management units.);
• Overland pathways—overland
transport (i.e., surface runoff and soil
erosion) to surface water or transport by
soil erosion to off-site fields;
• Soil pathways—on-site soil
exposures.
There are three types of pathways not
included in the analysis. Pathways
involving the use of contaminated water
(groundwater and surface water) for
irrigation were removed due to
modeling difficulties that could not be
resolved, however early results
indicated these are not the most
significant pathways for any of the
waste management units. Pathways
involving the deposition of
contaminated particles directly onto
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66362 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
surface water bodies were not included
because previous efforts by the Agency
have shown these pathways not to be as
significant when compared to particle
deposition onto the watershed and
subsequent erosion to the surface water
body. Pathways involving wet
deposition were not examined. An air
model recently developed evaluates the
impact of wet deposition and was not
available to use at the time of this
proposed rule. This new model also was
addressing problems with the area
component of earlier models. When the
model is available, the Agency will
determine whether its use will have an
impact on the proposed exit criteria. If
the Agency determines that there will be
an'impact, it will provide an
opportunity for public comment on use
of the updated model.
As stated earlier, not all exposure
pathways were evaluated for all waste
management units. Constituents may be
released from each waste management
unit by a variety of mechanisms. Each
release mechanism may be associated
with certain exposure pathways. By
examining the release mechanisms
assumed for each waste management
unit and identifying the exposure
pathways associated with those release
mechanisms, the appropriate pathways
to be modeled for each waste
management unit were identified. The
exposure pathways modeled for each
waste management unit are presented in
Table A-5 of appendix A.
b. Equations
Since the objective of the assessment
was to generate acceptable levels in
waste rather than determining risks
posed by waste, the equations, which
are designed to calculate risks, had to be
turned around or run in reverse. The
assessment began with a target risk (or
acceptable risk to the receptor) that was
used to back-calculate what constituent
concentration in a waste would not
exceed the target risk.
Wherever appropriate, the equations
used in the back-calculation were taken
from Methodology for Assessing Health
Risks Associated with Indirect Exposure
to Combustor Emissions (U.S. EPA,
1990x; hereafter, the Indirect Exposure
document, or IED) as modified by the
November 10,1993, draft of Addendum:
Methodology for Assessing Health Risks
Associated with Indirect Exposure to
Combustor Emissions, Working Group
Recommendations (U.S. EPA, 1993x;
hereafter, the Addendum). The
Addendum is currently being revised
based on comments from the Science
Advisory Board and is being combined
with the IED to generate a single
methodology guidance document.
Therefore, the equations may change
after that revision is completed. If this
occurs, the assessment used for this
rule-making will be revised. If such a
revision is needed and occurs, the
Agency will provide an opportunity for
public comment on those changes. For
convenience, the methodology
presented in the IED as modified by the
Addendum will be referred to as the
Indirect Exposure Methodology, or IBM. •
The equations presented in the IBM
were modified to estimate the soil
concentration for constituents eroding
to an off-site field. The IBM did not
address this pathway because it was
developed for stack emissions from
combustors rather than releases from
land-based units. However, because soil
erosion is a critical release pathway for
this analysis, the Agency applied the
Universal Soil Loss Equation (USLE)
and other equations presented in the
IEM to calculate soil erosion to the off-
site field. However, the application of
these equations resulted in
concentrations greater at the receptor
than in the waste management unit.
This phenomenon, first noted in the
Dioxin, reassessment, occurred because
the equations assumed that the amount
of uncontaminated soil that was eroded
into the field was negligible in
comparison to the total mass of soil in
the field. Therefore, the Agency
modified these equations to reflect
erosion of uncontaminated soil together
with the constituents.
Certain modifications to the equations
used in the assessment were made for
dioxin-like compounds to reflect the
different behavior of these constituents
in the environment. These
modifications were based on Estimating
Exposure to Dioxin-like Compounds,
Volume III: Site-Specific Assessment
Procedures (U.S. EPA, 1994x), hereafter
referred to as the Dioxin document. The
Dioxin document defines dioxin-like
compounds as "* * * compounds with
nonzero Toxicity Equivalency Factor
(TEF) values as defined in the 1989
International scheme * * * [which]
assigns nonzero values to all chlorinated
dibenzodioxins (CDDs) and chlorinated
dibenzofurans (CDFs) with chlorines
substituted in the 2,3,7,8 positions.
Additionally, the analogous brominated
compounds (BDDs and BDFs) and
certain polychlorinated biphenyls
(PCBs) have recently been identified as
having dioxin-like toxicity * * * and
thus are also included in the definition
of dioxin-like compounds."
Although the modifications presented
in the Dioxin document may be
applicable to other highly lipophilic
compounds, in keeping with this
definition, the modifications for dioxin-
like compounds were made only for
2,3,7,8-TCDDioxin Toxicity Equivalents
(TEQs), and PCBs. Other dioxin
congeners are addressed through the
2,3,7,8-TCDDioxin TEQ. The Agency
solicits comment on not using these
modifications for other highly lipophilic
compounds.
(3) Specific Issues on Pathways and
Equations
Below are specific issues of the risk
assessment related to the modeling of
the fate and transport pathways on
which the Agency is requesting
comment on their use, improvements to
them, or alternative ways to model
them. A detailed discussion of these
aspects is in Section 6, Fate and
Transport Modeling, of the Technical
Support Document for the Hazardous
Waste Identification Rule: Risk
Assessment for Human and Ecological
Receptors. (Air emission and dispersion
modeling is discussed in Section 7,
Waste Management Units, in the
technical support document. To be
consistent, issues related to that
modeling were presented earlier in this
preamble in Section D.2.a.)
(i) Hydrolysis
The Agency accounted for fate
processes (e.g., biodegradation,
hydrolysis) and transport processes
(e.g., volatilization) for constituents
throughout their movement from the
point at which the constituent leaves
the waste management unit until it
reaches the location at which contact
with the receptor occurs. During an
initial screen, the Agency identified four
constituents that were known to
hydrolyze completely or rapidly. These
constituents were not included in the
detailed assessment and include:
Benzotrichloride (98-07-7); maleic
anhydride (108-31-6); phthalic
anhydride (85-44-9); and 1,2-
diphenylhydrazine (122-66-7). In
addition, 16 inorganic salts known to
dissociate completely were also not
assessed. These included: Calcium
cyanide (592—01—8); copper cyanide
(544-92-3); potassium cyanide (151-
50-8); potassium silver cyanide (506-
61-6); silver cyanide (506-64-9);
sodium cyanide (143—33—9); thallium (I)
carbonate (6533-73-9); thallium (I)
chloride (7791-12-0); thallium (I)
nitrate (10102-45-1); thallium (I) sulfate
(7446-18-6); zinc cyanide (557-21-1);
zinc phosphide (1314-84-7); cyanogen
bromide (506—68—3); cyanogen chloride
(506-77-4); hydrogen cyanide (74-90-
8); and thallium acetate (563-68-8). The
Agency solicits comment on not
assessing these constituents.
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Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66363
Of the 192 constituents evaluated in
the non-groundwater analysis, the
Agency directly accounted for chemical
hydrolysis for 18 constituents. For the
remaining constituents, hydrolysis was
not considered for the following
reasons: The constituent has no
hydrolyzable chemical group;
hydrolysis is not expected to be
important or significant; the degradation
half-life of the chemical, which includes
hydrolysis, is greater than one year; or,
there was no data available for the
constituent.
The extent to which fate and transport
processes play a role in the removal of
a constituent from a pathway, or its
movement from one environmental
compartment to another is determined
by site-specific environmental
conditions as well as chemical-specific
parameters. To simplify the analysis, the
Agency used fate and transport data
based on one set of environmental
conditions to represent all possible
spatial and temporal environments
encountered in any given exposure
pathway. The Agency solicits comments
on this simplification for modeling fate
and transport processes throughout the
exposure pathways considered in the
MPA.
(ii) Other Fate and Transport Processes
Fate and transport processes other
than hydrolysis may be important in
determining the concentration of a
constituent reaching a receptor. The
Agency's approach to incorporate
consideration for these other processes
involved the use of biodegradation and
volatilization rates into the fate and
transport pathways, when applicable.
The Agency recognizes that the rate for
many chemical-specific fate and
transport processes (in particular,
biodegradation) varies with
characteristics of the environment (e.g.,
temperature, soil type). However, the
Agency simplified the non-groundwater
analysis by applying chemical-specific
fate and transport rates generically
across environmental settings found in
the various exposure pathways. This
simplification may overestimate the exit
level in some instances and
underestimate the exit level in other
instances. The Agency solicits
comments on this simplification for
modeling fate and transport processes
throughout the exposure pathways
considered in the non-groundwater
analysis.
(iii) Bioavailability
With regard to the metals examined in
the risk assessment, there is
considerable uncertainty about their
bioavailability that affects their fate,
transport, and uptake in various media
(e.g., plant tissue, animal tissue) and
receptors. Speciation and associated
solubility of metal species in wastes
which contain metals are key factors
that influence the bioavailability of
metals. The Agency had no information
on the speciation, solubility, or
availability of the metals in the wastes
in which they are disposed or how they
may transform in the environment. The
Agency assumed that the metals were in
a soluble form, mobile, and available. In
the absence of this information, the
Agency assumed that metals are soluble,
mobile, and bioavailable. The Agency
seeks comment on this approach, and
requests data on the speciation and
solubility of metals in wastes, together
with the conditions of the waste (e.g.,
pH) that could be disposed by the
methods considered in this rulemaking
and methodologies that account for the
transformation of the metals through
changing environmental conditions.
(iv) Meteorological Data
The approach for setting central-
tendency and high-end meteorological
conditions in the risk assessment was to
evaluate sets of meteorological data
from a variety of locations, and then
select locations that reflect central
tendency or high-end conditions for a
given exposure pathway.
The Agency used the set of 29
meteorological stations identified
during its efforts to develop soil
screening levels for Superfund sites.
These are considered representative of
the United States. Central-tendency and
high-end locations were then selected
from these 29 locations for the exposure
pathways where meteorological
conditions were required as input to the
models; these were the air pathways and
overland pathways. The meteorological
data were evaluated as location sets as
opposed to individual parameters. Once
locations were selected, the annual
average values for those locations were
used.
For air pathways, which required data
on wind speed, wind direction,
temperature, sunshine, cloud cover, and
air mixing height, selection of
meteorological data was waste
management unit-specific and based on
extensive sensitivity analysis. EPA
considered only the effect of
meteorological data on emissions and
dispersion in selecting locations for air
pathways. However, for consistency,
once a pair of high-end and central
tendency locations were selected for a
pathway, any meteorological data used
in that pathway were selected to
correspond to the locations chosen,
even in any overland transport
component of the pathway.
Overland pathways were driven by
soil erosion, for which the critical
meteorological input is the Universal
Soil Loss Equation (USLE) rainfall factor
(R). Therefore, to select central tendency
and high-end locations for overland
pathways, the 29 locations were ranked
based on the rainfall factor, and the 50th
and 90th percentile locations chosen for
all overland pathways.
See Section 6.8, Fate and Transport
Inputs and Section 7.1.5. Air Modeling,
of the Technical Support Document for
the Hazardous waste Identification Rule:
Risk Assessment for Human and
Ecological Receptors for a detailed
discussion of how meteorological data
were selected and used. The Agency
solicits comment on how meteorological
data was selected and used in the risk
assessment.
(v) Soil Data
A variety of soil parameters were
required for the modeling. These
parameters are interdependent and vary
with the type of soil (e.g., loam, clay).
However, values for these parameters
also vary within a soil type. Due to the
interdependence of the parameter, the
Agency chose to maintain them as a set
and determine a central-tendency
property set and a high-end property
set.
The Agency used loam type soils to
characterize all soils simulated in the
risk assessment because these types of
soils are fairly prevalent in the United
States. All soils are composed of varying
percentages of sand, silt, and clay.
Loam, by definition, is composed of
. equal proportions of sand, silt, and clay;
therefore, it represents a combination of
each of the physical properties of the
individual soil textures. Central
tendency and high-end values were
selected from the range of values for
loam soil so that each individual soil
parameter required by the model is
consistent with a loam soil. (Sec Section
6.8, Fate and Transport Inputs, in the
Technical Support Document for the
Hazardous Waste Identification Rule:
Risk Assessment for Human and
Ecological Receptors for more detail.)
The Agency solicits comments its
approach for characterizing soil in the
assessment.
(vi) Soil Pathways
The Agency seeks comment on the
following issues related to the modeling
of soil pathways:
• Use of the Universal Soil Loss
Equation to predict soil erosion in a
generic application - This is a widely-
used model intended for site-specific
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66364 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
applications where specific input data
can be used for relatively small fields.
Its use in a generic application, and for
fairly large waste management units,
may overestimate quantities of soil
eroded.
• Handling of the Soil Loss Constant
- This term is the sum of loss rates for
leaching, erosion, runoff,
biodegradation, hydrolysis, and
volatilization. Possible uncertainties
may arise because: the assessment
assumes that these terms are first-order
decay rates and therefore can be added
together; loss processes are calculated
independently, even though they may
occur simultaneously.
• Use of the Soil Water Content
Equation to predict soil water content in
a generic application - The equation is
from the Superfund Exposure
Assessment Manual (U.S. EPA, 1988x),
and was developed for site-specific
applications.
• Area of garden and agricultural
field - No data were available on the size
of home gardens, gardens on subsistence
farms, or yards of residential lots (for
soil ingestion). Therefore, a single set of
central tendency and high-end values
was estimated for these, based on best
professional judgment; this set is
referred to as garden area, even though
it might also apply to a yard. Because a
larger area leads to greater dilution of ;
deposited or eroded contaminant, a
high-end garden would be one that was
relatively small.
• Areas for agricultural fields were
estimated from data in the 1992 Census
of Agriculture (U.S. Department of
Commerce, 1992). The Census gives
average farm acreage by State for 48
States (the data are not yet complete for
the two missing States). No percentile
data were available. These data do not
distinguish between commercial and
subsistence farms.
• Mixing Depth—Mixing depth
reflects the depth of soil to which
deposited or eroded contaminant is
mixed. It is important to distinguish
between soil that is tille,d for
agricultural purposes and soil that is
untilled in determining appropriate
mixing depth values. A smaller mixing
depth results in less dilution of a
constituent, and therefore higher soil
concentrations; therefore, a high-end
mixing depth would be smaller than a
central tendency mixing depth.
(vii) Surface Water Pathways
Water column as well as benthic
sediment concentrations were
estimated. Water column concentrations
include dissolved, sorbed to suspended
sediments, and total (sorbed plus
dissolved, or total contaminant divided
by total water volume). Benthic .
sediment concentrations included:
Dissolved in pore water, sorbed to
benthic sediments, and total. The model
accounts for three routes of constituent
entry into the water-body were
examined: Sorbed to soils eroding into
the water-body; dissolved in runoff
water; and diffusion of vapor phase
contaminants into the water-body. Air
deposition of constituents bound to
particles into a water-body was not
examined because earlier analysis
demonstrated that its contribution
would be negligible when compared to
that of eroding particles. Volatilization
of dissolved constituents and removal of
constituents through burial in bed
sediments were modeled as loss
processes.
Important assumptions made for the
surface water modeling included:
Water-body sufficiently large to support
certain ecological receptors; sufficient
fish to support a subsistence fisher;
uniform mixing within the water-body
(this tends to be more realistic for
smaller water-bodies as compared to
large river systems); and equilibrium is
established between constituents within
the water column, bed sediments, and
air.
The Agency seeks comment on the
following issues related to the modeling
of surface water pathways:
• Water-body/Watersned
Characterization—The water-body
characterization parameters are another
example of a set of parameters that are
interdependent and therefore were used
as a group. Watershed characterization
relates to the water-body (in the case of
the assessment, a stream)
characterization. Streams are
characterized (flow, water-body area,
watershed area, depth, and various
other parameters) by their "order." A
first-order stream has no tributary
channels; a second-order stream forms
when two first-order streams converge,
and so 'on through stream order 10. The
Agency used a stream order 4 as the
high-end estimate because EPA believes
this stream order would be among the
smallest stream orders that would
support sufficient fish or a subsistence
fisher and the receptors assessed. A
stream order 5 was used as the central-
tendency estimate based on the number
of streams within each stream order.
(See Section 6.8 in the Technical
Support Document for the Hazardous
Waste Identification Rule: Risk
Assessment for Human and Ecological
Receptorsior more detail.)
• , Total Suspended Solids—Total
suspended solids (TSS) can range from
1 to 100 mg/L with a typical value being
10 mg/L for streams and rivers. This
value is used as the central tendency
value. No data on frequency of values in
actual streams was available to estimate
a 90th percentile value. Since 80 mg/L
is believed to be the maximum tolerable
value for aquatic life; this value was
used as the high-end value.
• Bed Sediment Concentration—The
bed sediment concentration term is
analogous to the bulk density for soil in
that it describes the concentration of
solids in terms of a mass per unit
volume. A single value of 1 kg/L was
used in the assessment given that this is
considered a reasonable value in most
situations and the range is quite narrow,
0.5 to 1.5 kg/L.
• Gas-Phase Transfer Coefficient—
The gas-phase transfer coefficient is
used to estimate volatile losses from the
water-body. Volatile losses are
calculated using a two-layer resistance
model that incorporates a gas-phase
transfer coefficient and a liquid-phase
transfer coefficient. Both transfer
coefficients are controlled by flow
induced turbulence in flowing systems.
The liquid-phase transfer coefficient is
calculated based on chemical-specific
properties. A single value of 36,500 m/
yr. was used. There is some uncertainty
related to setting this parameter to a
single value that is not chemical
specific. It is reasonable to assume that
chemical properties affecting volatility
would have some effect on this value,
although it is not known how large such
an effect would be.
• Fraction Organic Carbon in Bottom
Sediment—The fraction organic carbon
in bottom sediment is derived from the
fraction organic carbon in watershed
soils. For a fraction organic carbon of
about 0.01 in the watershed, the fraction
organic carbon for bottom sediments is
typically 0.03 to 0.05. The midpoint, of
this range, 0.04, divided by the fraction
organic carbon of the watershed (0.01)
derives a multiplier of 4 for calculating
fraction organic carbon in bottom
sediments from fraction organic carbon'
in watershed soils. The fraction organic
carbon values used of 0.024 and 0.008
correspond to the central tendency and
high-end values for soil fraction organic
carbon of 0.006 and 0.002, respectively.
The fraction organic carbon in the
bottom sediments was varied with the
fraction organic carbon in soil.
(viii) Food-Chain Pathways
The Agency seeks comment on the
following issues related to the modeling
of food-chain pathways: (Please note the
fish uptake methodology is described
below in Section D.2.C.2), Ecological
Receptors and Exposure; the littoral
methodology is used for humans):
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66365
• Use of regression equations based
on Kow to derive biotransfer factors for
plants—The biotransfer factors are
based upon empirical relationships with
Kow defined by studies on relatively
few chemicals.
• The lack of accounting for
translocation of contaminants within
plants—The plant uptake models do not
account for translocation of
contaminants (should such a
translocation occur) from one part of a
plant to another. The Agency is
considering two models developed by
Stephan Trapp, plantx and plantE, and
solicits comment on their use.
• Use of regression equations based
on Kow to derive biotransfer factors for
beef and milk—The biotransfer factors
for beef and milk are based upon
empirical relationships with Kow
defined by studies on relatively few
chemicals.
c. Receptors
Both human and ecological receptors
aro considered in the assessment. The
human receptors evaluated were
selected to represent a range of
behaviors and activities that influence
exposure levels. The Agency believes
that these represent typical and more
exposed types of behaviors and
activities that might exist around waste
management units or media
contaminated by releases from waste
management units. Each receptor was
evaluated for individual exposure
pathways (i.e., exposure to multiple
pathways was not included). For
ecological receptors, populations or
communities were selected for the
generic terrestrial and freshwater
ecosystems based on behavior patterns
such as dietary habits (plant-eater vs.
meat-eater) as well as qualities such as
significance and representativeness with
respect to trophic structure in the
ecosystem (bald eagle). The selection of
ecological receptors was limited by the
level of characterization available such
as food intake and body weight. Again,
the Agency believes that these represent
the types of organisms that might exist
around waste management units or
media contaminated by releases from
waste management units.
(1) Human Receptors and Exposure
Human receptors assessed in the
assessment included the following:
• Adult resident living in the vicinity
of a management unit—This individual
is representative of the general
population in the United States and is
evaluated independently through the
following potential exposure pathways:
Inhalation, ingestion of contaminated
soil, ingestion of contaminated drinking
water, dermal contact with
contaminated soil, and dermal contact
during bathing. In addition, the analysis
evaluates exposures to an adult resident
living on-site of a land application unit
begining 10 years after closure of the
unit.
• Child resident living in the vicinity
of a management unit—Children are a
special population considered in certain
pathways because of their low body
weight compared to high intake rates or
surface area. A child is evaluated
through the following potential
exposure pathways: ingestion of
contaminated soil, dermal contact with
contaminated soil, and dermal contact
during bathing.
• Home Gardener—This individual
represents a sub-population that
supplements their fruit and vegetable
consumption with fruits and vegetables
they grow on contaminated land.
• Subsistence Fisher—This
individual represents a sub-population
that subsists on contaminated fish.
• General Fish Consumer—This
individual represents a sub-population
that consumes contaminated fish and
supplements their intake with other
non-contaminated foods.
• Subsistence Farmer—This
individual represents a sub-population
that grows or raises most of their own
food on contaminated land. This
individual is evaluated independently
through the following exposure
pathways: beef ingestion, milk
ingestion, and fruit and vegetable
ingestion.
• On-site Worker—This individual
represents the working population that
may be found at the waste management
units. This individual is evaluated
during the active phase of the unit for
the following on-site exposures:
Inhalation and dermal contact with
contaminated soil.
Each of the receptors has been
matched with the most relevant
exposure routes. Table A-3 in appendix
A shows the pathways were modeled for
each receptor.
As previously discussed, the
assessment begins with a target human
toxicity benchmark and exposure
assumptions tailored to each receptor,
and back-calculates to constituent-
specific concentrations in each media.
In characterizing the exposure, two
exposure parameters are set to high-end
values and the rest of the exposure
parameters are set to central tendency or
default values. The two high-end
exposure values were typically exposure
duration and a parameter affecting.
intake of, or exposure to, a contaminant
(e.g., fraction contaminated,
consumption rate, inhalation rate).
The exposure equations used for back-
calculating media concentrations are
based on standard risk equations used
in most Agency risk assessments. For all
inhalation and ingestion pathways,
these equations were adapted from Risk
Assessment Guidance for Superfund
(RAGS): Volume I—Human Health
Evaluation Manual (Part B,
Development of Risk-based Preliminary
Remediation Goals) (U.S. EPA, 1991x;
hereafter, RAGS Part B) and subsequent
modifications. For dermal pathways,
which are not covered in RAGS Part B,
the equations presented in Dermal
Exposure Assessment: Principles and •
Applications, Interim Report (U.S. EPA
1992x; hereafter, the Dermal document)
were used; this document reflects the
current techniques for assessing dermal
exposure. The Agency requests
comment on the data sources and
assumptions used in the human
exposure portion of the risk assessment,
described in detail in Section 5.0 of the
Technical Support Document for the
Hazardous Waste Identification Rule:
Risk Assessment for Human and
Ecological Receptors.
The Agency seeks comment on the
following types of human exposure that
were not examined:
• Ingestion of contaminated water by
humans while bathing or swimming—
The ingestion rate of water while
swimming or bathing is 30 times smaller
than the normal consumption rate of
water used in the drinking water
ingestion pathways; therefore, the
drinking water ingestion pathways
should be protective of the incidental
water ingestion pathways.
• Inhalation of volatiles while
bathing—No appropriate, chemical-
specific equations could be found to
address this pathway.
• Ingestion of airborne particulates—
The ingestion rate of soil used in the
soil ingestion pathways is many times
larger than the ingestion rate from
airborne particulates; therefore, the soil
ingestion pathways should be protective
of the ingestion of airborne particulates.
Also, given the way the soil ingestion
rates were empirically derived,
ingestion of airborne particulates
should, in effect, be accounted for in the
estimated soil ingestion rates.
• Ingestion of contaminated soil by
resident on active site—While the waste
management units are active, it is
assumed that access is limited to
workers.
(2) Ecological Receptors and Exposure
In addition to the human receptors,
ecological receptors were evaluated in
the assessment. Lacking an Agency
precedent for the selection of ecological
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66366 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
receptors for a generic analysis, a simple
framework was developed for ecological
receptor identification based on EPA's
Framework for Ecological Risk
Assessment (U.S. EPA, 1992x). During
the problem formulation phase, a suite
of ecological receptors was selected to
include species that represent each of
the trophic levels or feeding habits
within an ecosystem. At best, one can
only infer that an ecosystem is protected
from chemical stressors. In addition, the
lexicological data support the
evaluation of individuals, populations,
and occasionally communities, but are
inadequate to address the complexities
of an ecosystem in most cases. Thus, the
approach taken in the assessment was to
estimate protective levels for the
populations and communities (inferred
from the measurement endpoints used)
found in generic ecosystems. The
species included in the ecological
assessment encompass a wide range of
dietary preferences, sizes, and trophic
levels.
hi selecting ecological receptors for
the assessment, a number of ecosystem
types (e.g., lakes, streams, estuaries,
deserts, forests, grasslands) were
considered because the waste could be
disposed anywhere once it has exited
the Subtitle C system. Two generic
ecosystems were designed: A
freshwater-based ecosystem and a
terrestrial-based ecosystem. Specific
details of these ecosystems are
described in Section 3, Receptors, in the
Technical Support Document for the
Hazardous Waste Identification Rule:
Risk Assessment of Human and
Ecological Receptors. The Agency
.solicits comment on both the adequacy
of the design of the ecosystems used in
the assessment and the use of generic
ecosystems to assess potential ecological.
hazards.
Generally, ecological receptors were
identified at different trophic levels as
well as at different levels of biological
organization and included species of
relatively low ecological significance
but high societal relevance (e.g.,
American kestrel). The final selection of
receptors was based primarily on the
availability of data with which to assess
the risks to that receptor. As suggested
in the Framework for Ecological Risk
Assessment (1992x), the process of
selecting appropriate assessment
endpoints was iterative, including
information from the other activities
included in the assessment phase—the
characterization of ecological effects.
The ecological receptors included in the
assessment were:
• Mammals—Mammals were
evaluated for both generic ecosystems
and include upper trophic level
predators such as the mink or red fox,
lower trophic level consumers such as
the whitetail deer, and insectiyores such
as the meadow mole; species were
selected to represent a variety of body
sizes, habitats, and dietary habits for
which data on body weight, food intake,
etc., are available. Mammals may be
exposed by eating contaminated prey
items (e.g., fish, other vertebrates,
insects) or plants, through incidental
ingestion of contaminated soil while
eating or preening, or through lactation
or placental transfer.
• Birds—Birds were also evaluated
for both generic ecosystems and include
upper trophic level predators such as
the red-tailed hawk and lower trophic
level consumers such as the American
robin; species were selected to represent
a variety of body sizes, habitats, and
dietary preferences for which input
parameters (e.g., body weight, diet,
ingestion rates) are available. Birds are
exposed through the ingestion of
contaminated prey items (e.g., fish,
worms), through incidental ingestion
that occurs while eating or preening, or
through maternal transfer to eggs.
• Terrestrial Plants—Vascular plants
that might be common in a generic
terrestrial ecosystem were evaluated.
The species of plants used to represent
plants within the terrestrial ecosystem
were determined by the availability of
data and included primarily forage
grasses and food crops. Plants are
exposed through soil-to-root uptake,
deposition on the surface of leaves or
bark, and during air-to-leaf transport of
volatile or semi-volatile constituents.
• Soil Community—Representative
species for the soil community were
based on six metrics for measuring
ecological function: (1) Location, (2)
size, (3) abundance, (4) taxon richness,
(5) trophic structure, and (6) energy
metabolism. Organisms living in or on
the soil are exposed through direct
contact (e.g., insects), through the
ingestion of contaminated soil (e.g.,
earthworms), and through the ingestion
of other soil dwellers (e.g., centipedes).
The Agency solicits comment on the
representative species selected to
comprise the soil community.
• Fish—Given the small percentage of
freshwater species for which
toxicological data are available, all
species of freshwater fish were
considered as potential receptors,
regardless of size or dietary habits. Fish
are subject to continuous exposure to
contaminated water via gill exchange
and may be exposed to bioaccumulative
chemicals through the food chain.
• Aquatic Invertebrates (Daphnids)—
Aquatic invertebrates are believed to be
among the most sensitive aquatic
species (Suter, 1993x), daphnids were
selected to represent free living aquatic
invertebrates. Continuous exposure to
contaminated water is considered the
primary route of exposure.
• Aquatic Plants—Vascular aquatic
plants and algae typical of aquatic
ecosystems were evaluated. Aquatic
plants are exposed during sediment-to-
root uptake and through water-to-leaf
transport.
• Benthic Community—
Representative species include
organisms that fall within any of the
eight taxonomic genera used in the
development of the Ambient Water
Quality Criteria for the protection of
aquatic life. Because these organisms
spend most (if not all) of their lives in
the sediment, they are exposed through
direct contact and ingestion of
contaminated sediments as well as
through the ingestion of other sediment
dwellers.
Each of these receptors has been
matched with the exposure pathways
and waste management units likely to
result in exposure. Table A-4 of
appendix A shows which pathways
were modeled for each receptor. The
Agency solicits comment on the use of
a single species to represent major
trophic elements.
The development of medium-specific
concentrations for the protection of
ecological receptors was based on
ingestion of contaminated vegetation,
water, soil, or prey or through continual
contact with a contaminated medium
(e.g., aquatic invertebrates with water or
soil fauna with soil).
Numerous studies have demonstrated
the capacity of hydrophobic organic
chemicals to bioaccumulate in the food
chain that are orders of magnitude
above the concentration in the
contaminated medium (e.g., Oliver and
Niimi, 1988x). However, it is important
to recognize that food-chain pathways
may be significant even for constituents
that do not bioaccumulate appreciably.
Dietary exposure to constituents that
concentrate weakly in fish tissue (e.g.,
bioconcentration factor below 10) may
be more significant than exposure to
contaminated drinking water simply
because a particular animal may ingest
relatively more fish than water.
For constituents that bioaccumulate,
particularly those that biomagnify,
benchmarks should account for
exposure through the ingestion of
contaminated prey as well as contact
with or ingestion of contaminated
media. The majority of toxicological
studies examined a single route of
exposure and seldom considered the
potential increase in exposure
concentrations through successive
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Federal Register / Vol. 60, No. 245. / Thursday, December 21, 1995 / Proposed Rules.. 66367
trophic levels. As a result, toxicity
benchmarks forbioaccumulative
constituents cannot be used as
acceptable medium exposure
concentrations; exposure estimates must
incorporate the bioaccumulation
potential in the food chain. For
nonbioaccumulating constituents,
where toxicity benchmarks that are
medium specific (i.e., concentration
units—mg/kg or mg/L)) can be used as
acceptable medium concentrations for
ecological receptors (e.g., Ambient
Water Quality Criteria).
In the aquatic ecosystem, for
bioaccumulative chemicals (log KoW>4),
bioaccumulation factors (BAFs) were
estimated using models developed by
Thomann (1989x) for the limnetic (or
pelagic) food chain and Thomann et al.
(1992x) for the littoral food chain (i.e.,
sediment-based). However, for
constituents with log Kow above 6.5,
only measured values were used. The
Agency is considering using the Gobas
model since it can be used for
constituents with log Kow above 6.5.
Further, switching to the Gobas model
would be consistent with the Great
Lakes Initiative which recently switched
to that model. The results produced by
either the Thomann models or the
Gobas model are very similar. The tissue
concentration (TC) was estimated for
prey based on the intake, body weight,
and dietary preference (i.e., trophic
level of fish consumed) of the
representative predator species.
Protective surface water concentration
was calculated by dividing the tissue
concentration (TC) by the
bioaccumulation factor for the
appropriate trophic level. For
nonbioaccumulative chemicals, the
protective surface water concentration
for fish and aquatic organisms was the
Final Chronic Value (FCV) or Secondary
Chronic Value (SCV) as described in
Section 4 of the Technical Support
Document for the Hazardous Waste
Identification Rule: Risk Assessment for
Human and Ecological Receptors. For
upper trophic level aquatic wildlife
such as mink and osprey, protective
surface water concentrations were
calculated based on the consumption of
contaminated fish and water. The
bonthic community was included in the
littoral ecosystem. Protective sediment
concentrations were estimated using the
equilibrium partitioning (Eqp) methods
developed by Di Toro et al. (1991x). As
explained in Section 4 of the Technical
Support Document for the Hazardous
Waste Identification Rule: Risk
Assessment for Human and Ecological
Receptors, the sediment benchmark was
calculated by multiplying the FCV (or
SCV) by the octanol/carbon partition
coefficient (Koc) and adjusting for the
fraction organic carbon (foe) in the
sediment. EPA requests comment on the
selection of the bioaccumulation model,
the potential switch to the Gobas model,
BAFs used, dietary assumptions, and
how'tissue concentrations were
calculated.
For receptors in the generic terrestrial
ecosystem, methods used represented a
range of dietary habits across trophic
levels for wildlife, including plants and
organisms that live in the soil (i.e., soil
fauna). (See the discussion on the
development of soil and plant
benchmarks elsewhere in today's rule.)
For higher trophic level wildlife, dietary
preferences, daily intake, and
bioconcentration factors for prey items
were identified or estimated to calculate
protective soil concentrations. The key
equation used to back-calculate soil
concentrations as a function of dietary
exposure (including soil ingestion), and
the exposure inputs (e.g., body weights,
daily intake) for ecological receptors are
discussed in Section 5.3 of the Risk
Assessment. The Agency requests
comment on the equations and inputs
used in the generic terrestrial ecosystem
modeling.
The following types of exposure were
not assessed in the assessment:
' • Inhalation by ecological receptors—
No suitable methodology was available.
• Dermal contact with soil—No
suitable methodology or sufficient
toxicity data were available.
• Dermal contact with water—No
suitable methodology or sufficient
toxicity data were available.
3. Groundwater Fate and Transport
Modeling
In the risk analysis previously
described in the section, the pathways
involving groundwater are only
modeled (back-calculated) to the
wellhead, i.e., to the point of exposure
at a water well. For groundwater
modeling from the waste management
unit (i.e., surface impoundment) to the
water well, the Agency used a separate
fate and transport analysis. This section
describes the groundwater model and
the modeling procedures for the various
waste management scenarios for the
groundwater path. The details of the
model and the modeling procedures are
presented in the background documents
(USEPA, 1995 a-f).
The Agency has developed
specialized subsurface fate and
transport modeling for four waste
management options: (1) Landfills; (2)
surface impoundments; (3) waste piles;
and (4) land application units. All four
waste management scenarios assume
that the waste if exempted could be
managed in the respective RCRA
Subtitle D units. In deriving the
exemption levels, the Agency needs to
evaluate the fate and transport of
constituents from the waste unit to the
nearby drinking water wells. The
potential migration of constituents from
a waste unit to the leachate at the
bottom of the waste unit can be
simulated by the laboratory test, the
Toxicity Leaching Procedure (TCLP), or,
the Synthetic Precipitation Leaching
Procedure (SPLP), Method 1312.
Although one procedure may be more
applicable for some wastes than the
other procedure, as described on page
21483 of the Federal Register Notice of
May 20,1992 (57 FR 21450), the Agency
is soliciting comments on the
applicability and use of one test over the
other for this proposal.
The fate and transport of constituents
in leachate from the bottom of the waste
unit through the unsaturated zone and
to a drinking water well in the saturated
zone is estimated using a fate and
transport model. The Agency proposes
to use EPACMTP (EPA's Composite
Model for leachate migration with
Transformation Products) for this
purpose. The EPACMTP considers not
only the subsurface fate and transport of
chemical constituents, but also the
formation and the fate and transport of
transformation (daughter) products. The
Agency also solicits comments on the
technical correctness and applicability
of the model and the data for this
proposal.
The Agency proposed the use of a
subsurface fate and transport model
(EPASMOD) on June 13,1986 (51 FR
21648) in the Toxicity Characteristic
(TC) Rule. However, after receiving
numerous comments, the Agency
revised the model and the data used in
the model (53 FR 28692) and the
enhanced model (EPACML) was used in
the TC Final Rule (55 FR 11798). The
EPACMTP replaces the EPACML for use
in this proposal. The EPACMTP was
recently published in a refereed journal
(Kool, Sudicky and Saleem, Journal of
Contaminant Hydrology 17(1994) 69-
90) and has been reviewed by the EPA's
Science Advisory Board (SAB). The
SAB commended the Agency for making
for its significant improvements to the
model. They also stated that it
represents the state of the art for such
analyses. However, they also
recommended additional testing of the
model.
The modeling approach used for this
proposed rulemaking includes three
major categories of enhancements over
the EPACML and the approach for the
TC rule. The enhancements fall into the
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66368 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
following categories: (1) Incorporation
of additional fate and transport
processes (e.g., degradation of chemical
constituents); (2) Use of enhanced flow
and transport solution algorithms and
techniques (e.g., three-dimensional '
transport); and (3) Revision of the Monte
Carlo methodology (e.g., site-based
implementation of available input data).
A discussion of the key enhancements
which have been implemented in the
EPACMTP is presented here and the
details are provided in the background
documents (USEPA, 1995a-g). The
Agency is soliciting comments on the
modeling enhancements and the
modeling methodology as well as on the
values derived for individual chemical
constituents:
(1) Fate and Transport Processes
Effects of groundwater mounding
underneath waste unit.—The EPACML
was limited to conditions of uniform
groundwater flow. It could not handle
accurately the conditions of significant
groundwater mounding and non-
uniform groundwater flow due to a high
rate of infiltration from the waste units.
These conditions increase the transverse
horizontal as well as the vertical
spreading of a contaminant plume. The
EPACMTP accounts for these effects
directly by simulating groundwater flow
in the vertical as well as horizontal
directions (USEPA, 1995 a).
Transformation products.—The
EPACMTP model has capability to
simulate the formation and fate of
multiple transformation products (up to
seven) in the unsaturated as well as in
the saturated zones. For constituents
which have toxic transformation
products, the EPACMTP can provide an
assessment of the groundwater impact
of the transformation products, along
with that of the parent constituent. This
methodology has been implemented for
hydrolyzing organic constituents
included in this proposal.
Fate and transport of metals.—The
EPACMTP can simulate fate and
transport of metals, taking into account
gebchemical influences on the mobility
of metals. The EPA's MINTEQA2
(USEPA, 1995 f) metals speciation
model is used to generate effective
sorption isotherms for individual
metals, corresponding to a range of
geochemical conditions. The transport
modules in EPACMTP have been
enhanced to incorporate the nonlinear
MINTEQ sorption isotherms. This
enhancement provides the model with
capability to simulate, in the
unsaturated and in the saturated zones,
the impact of Ph, leachate organic
matter, natural organic matter, iron
hydroxide and the presence of other
ions in the groundwater on the mobility
of metals.
(2) Enhanced Solution Algorithms and
Techniques
Linkage between unsaturated zone
and saturated zone modules.—The
saturated zone module implemented in
the EPACML was based on a Gaussian
distribution of concentration of a
chemical constituent in the saturated
zone. The module also used an
approximation to account for the initial
mixing of the contaminant entering at
the water table underneath the waste
unit. The approximate nature of this
mixing factor could sometimes lead to
unrealistic values of contaminant
concentration in the groundwater close
to the waste unit, especially in cases of
a high infiltration rate from the waste
unit. The enhanced model incorporates
a direct linkage between the unsaturated
zone and saturated zone modules which
overcomes these limitations of the
EPACML.
Numerical transport solution
modules.—To enable a greater flexibility
and range of conditions that can be
modeled, the analytical saturated zone
transport module has been replaced
with a numerical module, based on the
highly efficient state-of-the-art Laplace
Transform Galerkin (LTG) technique.
The enhanced module can simulate the
anisotropic, non-uniform groundwater
flow, and transient, finite source,
conditions. The latter requires the
model to calculate a maximum receptor
well concentration over a finite time
horizon, rather than just the steady state
concentration which was calculated by
the EPACML. The saturated zone
modules have been implemented to
provide either a fully three-dimensional
solution, or a highly efficient quasi-3D
solution. The latter has been
implemented for Monte Carlo
applications and provides nearly the
same accuracy as the fully three-
dimensional option, but is more
computationally efficient. Both the
unsaturated zone and the saturated zone
transport modules can accommodate the
formation and the transport of parent as
well as of the transformation products.
Solution for nonlinear metals
transport.—A highly efficient semi-
analytical unsaturated zone transport
module has been incorporated to handle
the transport of metals in the
unsaturated zone and can use
MINTEQA2 derived linear or nonlinear
sorption isotherms. Conventional
numerical solution techniques are
inadequate to handle extremely
nonlinear isotherms. An enhanced
method-of-characteristic based solution
has been implemented which
overcomes these problems and thereby
enables the simulation of metals
transport in the Monte Carlo framework.
Non-linearity in the metals sorption
isotherms is primarily of concern at
higher concentration values; for low
concentrations, the isotherms are linear
or close to linear. Because of the
attenuation in the unsaturated zone, and
the subsequent dilution in the saturated
zone, concentrations in the saturated
zone are usually low enough so that
properly linearized isotherms are used
by the model in the saturated zone
without significant errors.
Elimination of biases in determination
of receptor well location.—The internal
routines in the model which determine
placement of the receptor well relative
to the areal extent of the contaminant
plume have been revised and enhanced
to eliminate bias which was present in
the implementation in the EPACML.
The calculation of the areal extent of the
plume has been revised to take into
consideration the dimensions of the
waste unit. The logic for placing a
receptor well inside the plume limits
has been improved to eliminate a bias
towards larger waste unit areas and to
ensure that the placement of the well
inside these limits, for a given radial
distance from the unit, is truly
randomly uniform. However, for this
proposal, the closest drinking water well
is located anywhere on the
downgradient side of the waste unit and
the Agency is soliciting any comments
on this procedure.
(3) Revisions of Monte Carlo
methodology for nationwide assessment
Data sources.—The data sources from
which parameter distributions for
nationwide Monte Carlo assessments are
obtained have been evaluated, and
where appropriate, have been revised to
make use of the latest data available for
modeling. Leachate rates for Subtitle D
waste units have been revised using the
latest version of the HELP model with
the revised data inputs. Source specific
input parameters (e.g., waste unit area
and volume) have been developed for
various different types of industrial
waste units besides landfills. Input
values for the groundwater related
parameters have been revised to utilize
information from a nationwide industry
survey of actual contaminated sites.
Finite-source methodology.—The
original version of the model was
implemented for Monte Carlo
assessments assuming continuous
source (infinite source) conditions only.
This methodology did not take into
account the finite volume and/or
operational life of waste units. The
EPACMTP model has been
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Federal Register /Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66369
implemented for Monte Carlo
assessments of either continuous source
or finite source scenarios. In the latter
scenario, predicted groundwater impact
is not only based on the concentrations
of contaminants in the leachate, but also
on the amount of constituent in the
waste unit and/or the operational life of
the unit. The Monte Carlo methodology
was enhanced to allow determination of
regulatory threshold levels for these two
waste characteristics USEPA, 1995.
Site-based regional analysis.—The
Monte Carlo methodology has been
fundamentally revised and enhanced to
account for the interdependency among
the various model input parameters
based on regional distributions. The
original methodology simply assumed
that a waste site could be located
anywhere in the US, and that the
probability distributions of individual
model parameters (e.g., infiltration rate,
depth to groundwater, etc.) at any waste
site were mutually independent and
given by their nationwide frequency
distributions. The model therefore only
had limited capability to account for
correlations and dependencies among
the model parameters. To address this
limitation, a site-based methodology has
been implemented, based on the OSW's
surveys of existing waste facilities in the
US, and their geographical locations.
The information of geographical
location is used in this enhanced
approach to select the other model
Earameters, such as infiltration rate and
ydrogeological characteristics. A
number of different sources were
reviewed for the development of the
site-based approach. Four of these sets
were selected to derive the regional
characteristics of the more important
parameters for each sampled site: The
OSW's survey of industrial waste
management units (EPA, 1986); the
infiltration and recharge analysis
performed for U.S. climatic regions; the
U.S. Geological Survey inventory of
groundwater resources; and the API's
(American Petroleum Institute) survey
of hydrogeologic parameters for the
different groundwater environments in
the U.S.
(4) Implementation of EPACMTP
The specific modeling options
selected for the modeling analyses are
summarized in Table 3 below. All
modeling analyses were Conducted in
the finite source, Monte Carlo mode, for
four industrial Subtitle D waste
management scenarios. The
groundwater fate and transport model
was used to predict the maximum
concentration at a receptor well placed
down gradient from the waste unit. A
10,000 years time limit was imposed on
the exposure time period, i.e., the
calculated concentration is the highest
exposure concentration occurring
within 10,000 years following the initial
release from the waste unit. The Monte
Carlo fate and transport simulation
provides a probability distribution of
receptor well exposure concentrations
as a function of'waste and leachate
concentrations. For this proposal, the
groundwater modeling results were
used to derive leachate concentration
thresholds. For carcinogenic
constituents, the exposure concentration
calculated by the model corresponds to
the maximum 30-year average receptor
well concentration. For non-
carcinogenic constituents, the peak
receptor well concentration is used. The
regulatory threshold leachate
concentration limits were determined
using a back-calculation procedure, to
correspond to an approximate 90th
percentile protection level. This means
that the closest downgradient drinking-
water wells at 90% of the industrial
Subtitle D waste management units
would have water concentrations below
the HBN/MCL. The wells further away
at 90% of the sites would be protected ,
at higher protection levels. The wells at
the other 10% of the sites would be
protected at lower protection levels.
The Agency uses a 95th percentile
protection level in the RCRA Delisting
program and the 85th percentile for the
toxicity characteristic program. These
two programs have slightly different
goals from the exemption proposed
today. The recently developed
Superfund soil-screening levels use a
90th percentile protection level to
identify sites at which no additional
investigation for possible remediation is
required. The exit proposed today is
similar to the soil-screening levels
program. Today's proposed exit is
intended to identify wastes no longer
needing Subtitle C management.
Finally, the 90th percentile was chosen
because it is nearly consistent with the
protectiveness level in the other
pathways of the multipath risk
assessment performed for today's
proposal as far as could be identified.
Table 3 provides a summary of the
methodology and/or data sources used
to obtain values for the source-specific
parameters, chemical-specific
parameters, unsaturated zone
parameters, saturated zone parameters,
and receptor well location parameters.
Because the groundwater pathway
analysis was performed in Monte Carlo
mode, all parameters are in principle
described by their probability
distributions. Details on the actual
distributions used are provided in the
background documents (USEPA, 1995a-
g). Probability distributions used for the
unsaturated zone parameters, the
saturated zone parameters, and receptor
well location parameters were the same
for all waste management scenarios and
individual constituents that were
analyzed for today's exit.
(5) Waste Management Scenarios
The waste management unit
represents the source term in the fate
and transport model for the waste
management scenarios evaluated for
groundwater contamination. In the
modeling framework, the source is
defined in terms of four key parameters:
(i) Waste unit area, (ii) Leachate flux
(infiltration) rate, (iii) Leachate
concentration, and (iv) Duration of
leachate pulse. The first of these
parameters, waste unit area, was
determined from the nationwide OSW
survey of industrial Subtitle D waste
management facilities (USEPA, 1995 a-
b). After screening out records with
unreliable waste site area and/or
volume, the OSW Industrial Subtitle D
survey provides data on location, area
and volume of 790 landfills, 1655
surface impoundments, 774 waste piles,
and 311 land application sites
nationwide. The weighted distributions
of waste unit characteristics used as
input to the model are based on the
results of the survey.
The leachate flux, or infiltration rate,
and duration of the leachate pulse are
determined from the design and
operational characteristics of the waste
management scenario being modeled.
Consideration of a leachate pulse of
finite duration is a fundamental aspect
of the present analysis and distinguishes
it from the continuous source (infinite
source) assumption used for the 1990
Toxicity Characteristic (TC) Rule (55 FR
11798). It should be emphasized though
that the results of the finite source
analysis are not necessarily different
from those of the continuous source
analysis. If the source leaching duration
is long enough to drive the maximum
receptor well concentration to its steady
state value, the finite source and
continuous source analyses are in fact
the same. In practice, the distinction
between continuous source and finite
source analysis is the most important for
chemicals which are subjects to
sorption, speciation, and/or
degradation, including hydrolyzing
organics and metals.
The leachate concentration of specific
constituents in the waste forms the basis
for regulating the wastes. The leachate
concentration is not specified a-priori,
but rather it is back-calculated at the
end of the Monte Carlo analysis to
satisfy the regulatory criterion that the
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66370 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
maximum groundwater exposure
concentration should be at, or below,
the constituent-specific health-based
drinking water standard, in at least 90
% of the cases.
The following sections present
background on the determination of the
source parameters for each waste
management scenario.
Landfills.—The key characteristic of
the landfill scenario is that the duration
of the leachate pulse is independent of
the operational life of the waste
management unit, i.e., the period of
time required to fill the landfill. The
landfill is taken to be filled to capacity
and covered when leaching begins. The
time period during which the landfill is
filled-up, usually on the order of 20
years, is considered to be small relative
to the time required to leach all of the
constituent mass out of the landfill. The
model simulation results indicate that
this assumption is not unreasonable; the
model calculated leaching duration (see
below) is typically on the order of
several hundred years.
The leachate flux, or infiltration rate,
is determined using the HELP model.
The net infiltration rate is calculated
using a water, balance approach, which
considers precipitation, evapo-
transpiration, and surface run-off. The .
HELP model was used to calculate
landfill infiltration rates for a
representative subtitle D landfill with 2-
foot earthen cover, and no liner or
leachate collection system, using
climatic data from 97 climatic stations
located throughout the US. These
correspond to the reasonable worst case
assumptions as explained in the Risk
Assessment Background Document
(USEPA, 1995b). The model calculates '
the daily water balance for the total
period for which climatic data are
available. For each waste site in the
OSW survey, an infiltration rate was
calculated using the data from the
closest climate station (USEPA, 1995b).
In the landfill scenario, the duration
of the leaching period is not prescribed.
Instead it is calculated as part of the
Monte Carlo simulation from the total
mass of constituent in the landfill, and.
the rate of leaching. This relationship is
derived from a straight-forward mass
balance principles. The methodology is
documented in the Background
Document for the Finite Source
Procedure (USEPA, 1995-c); only the
most salient aspects are presented here.
The duration of the leachate pulse, Tp,
is determined by the total mass of
constituent that is initially present in
the landfill, and the rate at which the
constituent is removed by leaching:
Aw . d . Fh . Phw . Cv^=Aw . I. CL . TP
or
TP={d . Fh. Phw} over {1} Cw over CL
where
Aw=Area of the waste unit (m2),
d=Depth of waste unit (m),
Fh=Fraction of waste unit volume
occupied by this waste,
Phw=Density of the waste (g/cm3),
I=Leachate flux (Infiltration) rate (m/
y).
Cw=Constituent waste concentration
(mg/kg), and
CL=Constituent leachate
concentration (mg/L).
The determination of Tp according to
(2) tacitly assumes that the constituent
does not degrade inside the waste unit,
does not consider removal by
mechanisms other than leaching (e.g.,
volatilization), and assumes that all of
the constituent mass will eventually
leach out. The formulation given above
also assumes that the leachate
concentration, CL, remains constant
until all of the constituent mass has
leached out. The methodology was
adapted to handle a time-varying
leachate concentration, e.g., a gradually
diminishing leachate concentration to
represent the depletion of the
contaminant mass in the landfill over
time. If it is assumed that the leaching
of the constituent from the waste into
the water phase is controlled by a linear
equilibrium partitioning process, the
reduction of the leachate concentration
with time can be modeled as a first-
order decay process (EPA, 1995c):
CL(t)=CL°e{-Xt}
where
CL°=Initial leaching concentration
(mg/L)
A.=Apparent decay constant (y-1)
t=Time (y)
The rate at which the leachate
concentration is reduced is determined
by the coefficient X, which is given by:
!={!} over [{d FhwPhw}{Cw over CL°}]
Using (3), the leachate concentration
will gradually and asymptotically be
reduced to zero. The total amount of
constituent that is released into the
subsurface will be the same whether a
constant leachate concentration of finite
duration, or a gradually diminishing
leachate concentration is assumed. In
the latter case, the duration of the
release period is longer, but the average
leachate concentration lower, as
compared to the former case.
It can be seen from either (2) or (4)
that the duration of the leachate pulse,
or the rate of depletion, respectively,
can be expressed as a function of the
initial leachate concentration, CL. For
the modeling analyses, equation (3) was
used for organic constituents. The
underlying assumption that the
concentration is controlled by linear
equilibrium partitioning is reasonable
for organic constituents. For metals, the
pulse release option (equation 2) with
constant leaching concentration was
used.
The calculation of Tp (or X) requires
a number of ancillary source and waste
parameters. These are the depth of the
waste unit (d), the fraction of the waste
unit occupied by the waste (Fh), and the •
waste density (Phw). The waste unit
depth is obtained directly from the OSW
waste site survey. The survey provides
data on both landfill areas and volumes,
which allows the depth to be calculated
for any landfill selected during the
Monte Carlo simulation. The fraction of
waste in the landfill is assigned a
uniform distribution with lower and
upper limits of 0.036 and 1.0,
respectively, based on analysis of waste
composition in Subtitle D landfills
(EPA, 1995). The lower bound assures
that the waste unit will always contains
a minimum amount of the waste of
concern. The waste density is assigned
a value based on reported densities of
hazardous waste, and varies between 0.7
and 2.1 g/cm3 (EPA, 1995c).
Surface Impoundment.—The surface
impoundment waste management
scenario is that of a non-hazardous
waste industrial impoundment. The
area of the impoundment is obtained
from the OSW Subtitle D Industrial
Survey (USEPA 1995 b). No direct data
is available on the rate of infiltration
from surface impoundments. The rate of
infiltration from the impoundment is
calculated inside the EPACMTP fate and
transport model. The rate of infiltration
is calculated, using Darcy's Law, as a
function of surface impoundment depth,
and hydraulic conductivity and
thickness of a low-permeability
sediment layer at the base of the
impoundment.
Impoundment depth is obtained from
the OSW survey, for each impoundment
site in the survey, in the same way as
the landfill depth is obtained (see
above). The sediment layer at the base
of the impoundment is taken to be 2 feet
thick, and have an effective equivalent
saturated conductivity of 10-7 cm/s .
These values were selected in
recognition of the fact that most non-
hazardous waste surface impoundments
do have some kind of liners in place
(USEPA, 1995b). During the Monte
Carlo fate and transport simulation, the
infiltration rate is calculated using the
impoundment depth value for the
specific unit selected for each Monte
Carlo realization.
The leachate concentration again is
not determined a priori, but is
determined after the analysis, based on
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the desired regulatory protection level
(90th percentile). The surface
impoundment is taken to have a 20-year
operational life. After this period, the
impoundment may be filled in, or
simply abandoned. In the latter case, the
waste in the impoundment will drain
and/or evaporate relatively quickly. In
the modeling analysis, the duration of
the leaching period is therefore set equal
to 20-years.
Waste Pile.—The waste pile
management scenario is conceptually
similar to that of the landfill, but differs
in a number of key aspects. In contrast
to landfills which represent a long-term
waste management scenario, waste piles
represent a more temporary
management scenario. During the
operational life of the waste pile, it may
bo regarded as an uncovered landfill.
Typically at the end of the active life of
a waste pile, the waste material is either
removed for land filling, or the waste
pile is covered and left in place. If the
waste is removed, there is no longer a
source of potential contamination. If a
waste pile is covered and left in place,
it then becomes equivalent to a landfill,
and consequently is to be regulated as
a landfill. For the analyses, therefore,
only the groundwater impacts
associated with the period that the
waste pile is active, are considered.
Data on the waste pile area are
obtained from the OSVV Subtitle D
survey. Infiltration rates for the waste
pile are obtained by treating the waste
pile as an uncovered landfill. HELP
model derived landfill infiltration rates
assuming a sandy loam soil cover were
used to assign infiltration rates for waste
piles. A sandy loam cover represents the
most permeable cover considered for the
landfill scenario, and most closely
resembles a situation in which no cover
is present. The methodology for
assigning an infiltration rate to any
specific waste pile in the OSW survey
follows that used for landfills (see
above).
An active life of 20 years is assumed
for the waste pile. This also determines
the duration of the leaching period. As
with the landfill and surface
impoundment scenario, the leachate
concentration is determined at the end
of the analysis, to satisfy the regulatory
protection level.
Land Application Units.—Data on the
location, area and waste application
rates at industrial land application sites
\vero obtained from the OSW survey of
industrial Subtitle D sites. Location-
specific infiltration rates were estimated
for each land application site by
applying the HELP model, using
climatic data from the nearest climate
station. Because wastes applied at land
application sites typically have a high
liquid content, this factor was
accounted for in the water balance
calculations. An annual waste
application rate of six niches of waste,
containing 85% water was assumed.
This is typical of sludges which
constitute a large fraction of waste at
land application sites. Therefore, an
additional 5.1 inches of water were
added to the natural precipitation for
the water balance evaluation at each
land application site.
Theleaching duration for the land
application unit was set to 40 years,
consistent with the release period-
modeled for the air pathway. No reliable
data were available for the active life of
land application units. Using a longer
value than for surface impoundments
and waste piles is warranted because
part of the applied waste material may
remain in the soil at the end of the
active life of a land application unit,
and may continue as a source of
contaminant leaching.
(6) Determination of Regulatory Waste
and Leachate Concentration Limits
The objective of the Monte Carlo fate
and transport analysis is the
determination of regulatory limits for
the concentration of individual toxic
constituents in the leachate, CL- These
limits are determined so as to satisfy the
regulatory criterion that disposal of a
waste in a subtitle D waste management
unit should not lead to an exceedance
of the health-based value or the drinking
water standard, at a receptor well placed
down gradient from the waste unit, in
at least 90% of the cases.
The CL limits are specific to each
waste management scenario, and are
also constituent specific. CL limits are
constituent specific because of their
dependence on constituent specific
health-based standards, as well as on
constituent specific fate and transport
characteristics that affect the
concentration received at the receptor
well. The latter factors are discussed in
the following section; this section
discusses the determination of
regulatory CL thresholds.
Using Equation (2) or (3) and (4), the
groundwater exposure concentration
calculated by the fate and transport
model can be expressed as a function
CL. All other parameters used in the
modeling analysis are obtained from
prescribed probability distributions.
Consequently, by comparing the
predicted exposure concentration to the
appropriate regulatory standard, e.g.,
health-based value or a drinking-water
standard, threshold levels of CL, can be
calculated. Wastes for which the
leachate concentration exceeds the CL
threshold would not be exempted.
Because the Monte Carlo analysis
produces a probability distribution of
exposure concentrations, the back-
calculation of CL threshold levels can be
performed for any desired level of
protection.
For those constituents that degrade
(see next subsection) and produce toxic
degradation products, the development
of regulatory threshold values for CL
considers not only the exposure
concentration and toxicity of the parent
constituent, but also the exposure
concentration and toxicity of toxic
transformation products. For instance,
consider two waste constituents that
have similar toxicity values, i.e., similar
health-based levels, as well as similar
fate and transport characteristics, so that
they show comparable values for the
model simulated receptor well exposure
concentration. However, if one of the
two chemicals produces toxic off-spring,
but the other chemical does not, the
chemical which has toxic daughter
products will have more stringent limits
for CL.
(7) Chemical—Specific Fate and
Transport Processes
The Monte Carlo fate and transport
analysis considers chemical-specific
sorption and hydrolysis (degradation)
characteristics. These characteristics
directly affect the model-predicted
groundwater exposure concentration.
Chemicals which are subject to sorption
and/or hydrolysis will exhibit lower
exposure concentration as compared to
non-sorbing, non-degrading chemicals.
This translates into higher regulatory
waste and concentration limits. Two
broad groups of chemicals are
considered under today's proposal.
They are organic constituents and
metals.
Organic Constituents.—Organic
constituents account for the largest
group of chemicals addressed under
today's proposal. The groundwater
pathway analyses were performed for a
total of 222 organic constituents. The
fate and transport analysis accounts for
sorption of organics onto soil and
aquifer organic matter, as expressed by
a chemical-specific organic-carbon
partition coefficient (Koc), and
degradation due to hydrolysis reactions,
as expressed by chemical-specific
hydrolysis constants. Sorption is
modeled as a reversible, linear
equilibrium process. Degradation due to
hydrolysis is modeled as a first-order
kinetic process. The groundwater
pathway analysis utilizes a
comprehensive set of Koc values and
hydrolysis rate constants compiled by
the EPA-ORD (Environmental Fate
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66372 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
Constants for Organic Chemicals Under
Consideration for EPA's Hazardous
Waste Identification Projects , EPA/600/
R-93/132). Chemicals with identical
Koc values and hydrolysis constants
will exhibit the same fate and transport
behavior, and given the same leachate
concentration and leaching period, they
will result in the same exposure
concentration. Note, however, that they
may still have different regulatory
leachate concentration limits, if they
have different health-based drinking
water standards and/or produce toxic
transformation products.
For the groundwater pathway
analysis, organic constituents with a
hydrolysis half-life of 6,900 years or less
(first-order degradation rate of 10-4 or
greater) were classified as degraders, the
remainder were classified as non-
degraders. The EPACMTP can simulate
the formation and subsequent fate and
transport of transformation daughter
products, enabling the groundwater
exposure concentrations of any toxic
transformation products to be
determined and, therefore, included in
the determination of leachate
concentration thresholds.
It has been established, by analyzing
modeling results for different
constituents with a range of sorption
and degradation characteristics that,
after normalizing the results against the
chemical-specific HBN/MCL, the effect
of sorption and degradation on the
regulatory values can be expressed as a
function of the Koc and hydrolysis rate
coefficients, using a straight-forward
scaling relationship. After these
relationships have been established, it is
not actually necessary to conduct the
Monte Carlo fate and transport
computer simulations for each
individual constituent. Instead, for each
waste management scenario of concern,
a set of reference CL values are
generated by running the Monte Carlo
model for a selected range of values of
Koc and hydrolysis rate coefficients
using a normalized HBN/MCL of 1 ing/
L. Constituent-specific CLMIN values are
then determined in two steps: First, the
reference curves are scaled to the
constituent specific Koc value, and (for
degraders) hydrolysis rate coefficients.
Secondly, an adjustment is made for the
constituent-specific value of the
drinking water standard. The final
values of CLMIN are obtained by
multiplying the concentration limits
based on the normalized drinking water
standard, by the actual value of the
drinking water standard of that
particular constituent. For constituents
with toxic transformation products, this
TABLE 3.—EPACMTP MODELING OPTIONS
procedure is repeated for the
transformation products, to find the
minimum values of CL (CLMIN) which
ensure that the exposure concentrations
of the parent constituent and any
daughter products will not be exceeded.
The benefit of this approach is that if
additional constituents are to be
regulated, or a different value of the
drinking water standard HBN/MCL, the
appropriate CLMIN can be determined
with less effort, because it is not
necessary to repeat the time-consuming
complete Monte Carlo simulation.
Metals.—Fate and transport of metals
in the subsurface may be controlled by
complex geochemical interactions. To
account for these processes, the OSW
has developed and implemented a
modeling approach which utilizes the
MINTEQA2 metals speciation model in
conjunction with the EPACMTP
subsurface fate and transport model.
The MINTEQ model has been applied to
generate effective sorption isotherms
reflecting variations in four geochemical
master variables affecting metals fate
and transport. These factors are: Ph,
leachate organic matter natural organic
matter in the soil or aquifer, and
ironhydroxide content. Each of these
parameters has a range of values,
reflecting their nationwide probability.
Management Scenarios Industrial Subtitle D: (i) Landfill; (ii) Surface Impoundment; (Hi) Waste Pile; and (iv)
Land Application Unit.
Modeling Scenario Finite Source Monte Carlo.
Regulatory Protection Level 90% (yields an approximate DAF of 10 for a continuous source landfill)
Source Parameters:
Waste Unit Area Site based, form OSW Industrial Subtitle D Survey.
Waste Unit Volume Site based, from OSW Industrial Subtitle D Survey
Infiltration Rate:
Landfill Site-based, derived from water balance using HELP model.
Surface Impoundment Site-based, derived from impoundment depth using Darcy's law.
Waste Pile Site-based derived .from water balance using HELP model.
Land Application Unit Site-based, derived from water balance using HELP model.
Leaching Duration:
Landfill Derived, continues until all constituent has leached out.
Surface Impoundment 20 years (operational life of waste unit).
Waste Pile Land 20 years (operational life of waste unit).
Application Unit 40 years.
Chemical Specific Parameters:
Decay Rate:
Organics Hydrolysis rates based on measurements or based, on appropriate structure-activity re-
lationships.
Metals No decay.
Sorption:
Organics , Koc estimated from Kow, which is based on measurements or based on appropriate
structure-activity relationships.
Metals MINTEQ sorption isotherms (Pb, Hg, Ni, Cr (111), Ba, Cd).
pH dependent isotherms (As, Cr (VI), Se (VI), Th)
Unsaturated Zone Parameters:
Depth to groundwater .; Site-based, from API/USGS hydrogeologic database.
Soil Hydraulic Parameters National distribution for the main soil types.
Fraction Organic Carbon National distribution for the main soil types.
Bulk Density National distribution for the main soil types.
Saturated Zone Parameters:
Recharge Rate Site-based, derived from precipitation/evaporation and soil type.
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Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66373
TABLE 3.—EPACMTP MODELING OPTIONS—Continued
Saturated Thickness Site-based, from API/USGS hydrogeologic database.
Hydraulic Conductivity Site-based, from API/USGS hydrogeologic database.
Porosity .'. Effective porosity derived from national distribution of aquifer particle diameter.
Bulk Density Derived from porosity.
Disparsivity Derived from a national distribution and is based on distance to the receptor well.
Groundwater Temperature Site-based, from USGS regional temperature map.
Fraction Organic Carbon National distribution, from EPA STORET database.
pH National distribution, from EPA STORET database.
Receptor Well Location:
Radial Distance Nationwide distribution based the survey.
Angle Off-Center Uniform within + 90° from plume centerline.
Deplh of Intake Point (No restriction to be within plume) Uniform throughout saturated thickness of aquifer.
4. Other Risk Assessment Issues
a. Differences Between the Groundwater
and Non-groundwater Analyses
As mentioned previously, the Agency
conducted separate analyses for the
evaluation of risks from groundwater
and non-groundwater pathways. The
groundwater pathways relied on a full
Monte Carlo analysis; whereas the non-
groundwater pathway analyses were
performed using high-end and central
tendency parameters, consistent EPA's
risk characterization guidance (EPA
1995).
Although the approaches to the
modeling differed, the Agency used the
same data for parameter inputs (i.e.,
OSW's Industrial Suhtitle D Survey,
U.S. EPA 1986) to describe the waste
management units common to both
analyses (i.e, surface impoundments,
waste piles, and land application units).
However, even though the same data
were used, some differences exist based
on the different modeling approaches.
These differences are discussed below.
(1) Infiltration
For tho groundwater pathway
analysis, the Agency used the HELP
model to calculate die net infiltration
rate for landfills, land application units
and waste piles, as a function of
regional climatic conditions and waste
unit design characteristics (see
EPACMTP background Document). The
analysis used the meteorological data
from 93 meteorological stations located
throughout the United States to develop
infiltration rate distributions using the
HELP model.
For the non-groundwater analysis, the
Agency used rainfall to calculate the
recharge rate. The rainfall was selected
from 29 meteorological stations
distributed among 9 climate regions.
However, the method for selecting the
rainfall factor differed between the air
release pathways and the overland
release pathways.
• For the air release pathways, the
Agency conducted a sensitivity analysis
for each waste management unit type to
rank the 29 meteorological stations with
respect to several air modeling outputs,
including maximum air concentration of
pollutants, average air concentrations
over the agricultural field and water
body, and average deposition over the
agricultural field and water body. Based
on these sensitivity analyses, the
Agency selected a central tendency
location and high-end location for the ,
ail pathway for each of the waste
management units. Thus, locations with
meteorologic data, including the rainfall
factor, approaching the central tendency
and high-end values were selected for
each waste management unit.
• For the overland release pathways,
the Agency ranked the rainfall factors
from the 29 meteorological stations and
selected the 50th and 90th percentile
based on the distribution of the 29
meteorological stations.
(2) Density of Waste Applied to the
Land Application Unit
The approach used in the
groundwater analysis assumed the bulk
density of the applied waste to be 1
gram per cubic centimeter (g/cc)
because the waste was assumed to be
comprised predominantly of water.
However, changes in the density of
applied waste do not significantly affect
the results of the groundwater modeling
results.
The approach used in the non-
groundwater analysis assumed the bulk
density of waste to be analogous to the
density of sewage sludge (i.e., 1.4 g/cc).
The waste in the LAU is a mixture of
industrial waste and soil. The central
tendency bulk density for soil (i.e., 1.5
g/cc) is similar to the bulk density
assumed for industrial waste. Because
the waste is incorporated into soil, the
properties of the waste/soil mixture are
needed. There is little variability in bulk
density for the type of soil used in the
analysis (i.e., loam), thus, the same
value was used for central tendency and
high-end estimates of the waste/soil
mixture bulk density.
(3) Unsaturated Zone Characteristics
The groundwater pathway analysis
used the characteristics (e.g., percent
organic matter, saturated hydraulic
conductivity) of the entire unsaturated
zone as input into the modeling
analysis. The non-groundwater pathway
analysis used as input the
characteristics of only the upper
portions of the unsaturated zone
because these characteristics were those
significant for the surface exposure
pathways.
(4) Hydrolysis Rates :
The hydrolysis rate for a chemical
constituent is used in the Monte Carlo
groundwater pathway analysis as a
function of temperature and pH of the
groundwater at the Monte Carlo realized
site. The Agency used hydrolysis rates
for constituents that have been
measured through appropriate structure
activity relationships. They have been
reviewed by a panel of experts from the
Agency's Office of Research and
Development (USEPA, 1993). The non-
groundwater pathway analysis used
hydrolysis rates from the "Handbook of
Environmental Fate and Exposure Data
for Organic Chemicals" (Howard et. al,
1993).
b. Other Groundwater Pathway Analysis
Issues
(1) Use of 1,000 Year Versus 10,000 Year
Exposure Time Horizon
The Agency's proposal is based on a
10,000 year time horizon for the
groundwater pathway. This means that
the determination of leachate
concentration limits is based on the
highest (30-year average) concentration
that occurs within 10,000 years from the
start of the release. Although this longer
time horizon has been used in other
programs (U.S. Nuclear Regulatory
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66374 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
Commission and U.S. Department of
Energy), the Agency is considering
using 1,000 years as an alternative time
horizon. The Agency requests comment
on this issue which is described in more
detail below.
Using this shorter time horizon results
in an increase of the leachate
concentration limit for a number of
constituents. The constituents affected
are those which are strongly sorbed in
the subsurface, and which therefore
tend to migrate slowly. These
constituents include organics with
retardation factors (R) significantly
greater than one. The organic carbon
partition coefficient (koc) values for
these constituents are about 3,500 g/cm3
or greater, and certain metals such as
lead and chromium(III). For organic
constituents with koc values less than
about 3,500 g/cm3, the highest receptor
well exposure concentration is generally
reached in less than 1,000 years.
Reducing the modeling time horizon
from 10,000 to 1,000 years therefore
does not affect the results of the
pathway analysis for these constituents.
The effect of using a 1,000 year versus
a 10,000 year time horizon is illustrated
in Table 4. The constituent-specific
differences are shown in Table B-l of
appendix B to the preamble. The table
is based on a landfill waste management
scenario, and all constituents are
assumed to have identical toxicity
values and not be subject to hydrolysis.
For reference, the leachate
concentration limit for constituents with
koc=0 (no sorption, R=l), and a 10,000
year time horizon is equal to 1.0 mg/L.
This table shows that the increase in
leachate concentration limit for organic
constituents is affected for a shorter
modeling horizon (1,000 years) only
when koc values (or R values) are very
large. (About fifteen percent, out of a
total of approximately 200, including
eight metals, fall into this category.) The
effect of hydrolysis rate is not
considered in results shown in the table.
While hydrolysis influences the
magnitude of the exposure
concentration at a receptor well, the
time that it takes for a contaminant to
reach the receptor well is independent
from the chemical-specific hydrolysis
rate. It is, however, strongly influenced
by chemical-specific sorption
characteristics, which for organics are
expressed in terms of koc or R values.
TABLE 4.—EFFECT OF 1,000 YEAR
VERSUS 10,000 YEAR, MODELING
TIME HORIZON ON LEACHATE CON-
CENTRATION LIMIT
Kx (cmV)
0.0
3,384 .
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used for landfill modeling. As an
alternative, the Agency has used the
HELP model to calculate infiltration
rates for waste piles directly. In the
initial evaluation, the runoff used in the
water balance calculation was computed
by the HELP model as a function of soil
texture and vegetative cover Cbare
ground).The Agency has evaluated the
impact of representative bare, but
unevenly surfaced, waste piles on
simulated runoff using the HELP model.
A comparison of the impact of using
this alternative procedure against the
values used in this proposal for the base
case, on the regulatory leachate
concentration limit, was conducted. The
comparison of regulatory leachate
concentration limits is based on a non-
degrading, non-sorbing constituent,
which has a concentration limit of 1.0
mg/L in the proposal. Using the
alternative procedure, the
corresponding leachate concentration
level changes to 0.77. The Agency is
inviting comments on the two methods
for the waste piles for the estimation of
infiltration rates through them. If you
have any data and other information to
support your comment, send it along
with your comments to the Docket.
(5) Land Application Unit Infiltration
Rates
In the calculation of infiltration rates
for land application units for the base
case in the proposal, it was assumed
that land application units receive, on
average, 1,295.4 m3ha (5.1 inches) of
water annually through the application
of the waste. This amount of water was
included in the HELP model water
balance calculation, resulting in an
increased net infiltration as compared to
ambient conditions. The waste
application rate may or may not
represent true field situations. As an
alternative to the modeling procedure
used for the base case of this proposal,
the Agency evaluated the effect of using
ambient recharge rates, i.e., the
application of waste does not
significantly alter the water balance, on
the calculated leachate concentration
limits. The comparison of this
alternative with the procedure used for
the base case shows that the regulatory
leachate concentration limits for a non-
degrading, non-sorbing constituent in
land application units changes to 1.12
mg/L from 1.0 mg/L for the procedure
used in the base case.
(6) Aggregate Effects of Alternative
Groundwater Modeling Procedures and
Data
The preceding sections have
presented the effect of alternative
modeling options and data sources that
have been considered by the Agency. A
consequence of the Monte Carlo
exposure modeling approach is that the
effects of changes in model parameters
are not always linearly additive; rather
the aggregate effect of changing multiple
parameters or options may be to either
magnify or reduce the effect of the
individual changes. The Agency,
therefore, has conducted modeling
analyses of the aggregate effect of the
alternatives discussed above for each of
the four waste management scenarios. In
addition to the alternatives presented in
the preceding subsections, a
modification was also made in the
procedure for modeling waste sites for
which the corresponding
hydrogeological region was initially
assigned as "not classifiable". Rather
than ignoring the small fraction of sites
involved, they were incorporated into
the analysis by assigning them
nationwide average values for the
groundwater parameters. Table 5
presents the aggregate effect of all
changes for each of the four waste
management scenarios modeled. The
modeling results correspond to a non-
degrading, non-sorbing constituent. The
leachate concentration limits are
normalized with respect to a value of
1.0 mg/L for the landfill scenario, under
the modeling procedure for the base
case of this proposal. The results are
presented for a 1,000 year time horizon;
however for a non-sorbing constituent,
these same results also hold for the
10,000 year time horizon.
TABLE 5.—AGGREGATE EFFECT OF
MODELING ALTERNATIVES ON
LEACHATE CONCENTRATION LIMITS
FOR NON-DEGRADING, NON-
SORBING CONSTITUENTS FOR FOUR
WASTE MANAGEMENT SCENARIOS
Waste management
scenario
Landfill
Surface Impoundment
Waste Pile
Land Application Unit
HWIR
proposal
1.0
0.22
0.29
0.08
Alter-
native
Options
0.71
0.27
484
0.22
Table 5 shows that, except for
landfills, the aggregate effect of the
combined alternative options is a less
conservative (higher) leachate
concentration limit. For landfills,
adoption of the alternative modeling
options would have resulted in a 30 %
less stringent regulatory leachate limit
for the groundwater pathway for non-
sorbing and non-degrading constituents.
For surface impoundments, there is
little overall impact because the
opposing effects of increasing the
impeding layer hydraulic conductivity,
and the alternative Monte Carlo
procedure for handling parameter
bound exceedances, nearly cancel out.
For waste piles on the other hand, the
procedure used for the base case, results
in a significantly more conservative
leachate concentration limit as
compared to the alternative modeling
options. This is due to the handling of
parameter exceedances in the Monte
Carlo simulation. Because many waste
piles have very small sizes (surface
areas), the alternative Monte Carlo
procedure has a large impact. For land
application units, the procedures used
in the proposal for the base case also
result in a more conservative regulatory
limit as compared to the alternative
modeling options. The contributing
factors are much the same as for waste
piles, but the overall impact is much
smaller, primarily because there are
only few land application units with
very small areas.
F. Additional Eco-Receptor
Considerations
EPA considered two different policy
goals with respect to protection of
terrestrial ecological receptors (i.e., soil
fauna, birds, mammals, and plants). One
goal protected terrestrial ecological
receptors outside the boundaries of the
waste management site, thus, the
constituent had to travel off-site before
exposures would be assessed. The
alternative goal protected terrestrial
ecological receptors on the closed land
application site.
The Agency chose to propose exit.
levels based on off-site impacts for
several reasons. One reason is that there
are many land use decisions that
significantly affect terrestrial ecological
receptors on the property of a party
making those decisions (e.g., a decision
to pave a portion of land as a parking
lot). EPA does not generally regulate
those sort of decisions. However, many
impacts are judged through local zoning
regulations. Congress has typically
asked EPA or other Federal entities to
regulate activities on a property when
there are significant off-site impacts,
such as a groundwater plume that
migrates, an air release that moves
beyond the property, a wetland (located
on the property) that is a significant
resource for migratory birds and has
broader ecological significance, or an
endangered species with social values
beyond the impact on a specific
landowners purview.
EPA asks for comment, however, on
the alternative of protecting terrestrial
ecological receptors on-site. The
rationale for this alternative approach
would relate to protection from impacts
qn bird and mammal populations, and'
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66376 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules •
other ecological receptors, and to the
regulation of certain constituents that
could potentially result in
environmental consequences that go
significantly beyond the bounds of a
current waste management unit.
G. Background Concentrations in Soils
and Other Issues Relating to Results
EPA has compared the exit levels for
nonwastewaters to data on the variation
in mean background concentrations
found in soils. For some metals, the exit
levels calculated based on risks at land
application units are below 4 mean soil
concentrations. One reason exit criteria
may be below soil concentrations is that
these metals bioaccumulate, causing
greater exposure for higher trophic
levels. Also, the acceptable levels for
some of the metals that would be
calculated for practices other than land
application are significantly higher and
not below mean soil concentrations,
If the final exit levels are below
typical soil levels, EPA would consider
promulgating levels based on
concentrations that are either typical
soil concentrations (national mean
levels) or some percentile or portion of
the naturally-occurring range such as
the 10th percentile. If the effect of
concern is an ecological impact, the
rationale for using the 10th percentile
(or similar figure if the data available
does not allow that precision) would be
that in 90 percent of locations, if the soil
already contains those or greater levels,
the ecological receptors existing in the
area should already reflect the toxicity
of the waste material; the rational for
using the 10th percentile (or similar
value) value is that human behavioral
practices (e.g., treatment of groundwater
prior to use) may already reflect
protection from the potential toxicity of
concern. EPA asks for comment on
whether these are reasonable arguments.
EPA is concerned, however, that there
are also issues of the chemical and
physical form in which compound or
chemicals exist, in both natural
conditions and in the waste and that a
simple comparison of total
concentrations in soils and in wastes
might be misleading about potential
ecological or human impacts. EPA
requests comment on these issues.
EPA's first preference will be to
reexamine the risk modeling to identify
any inappropriate assumptions or
modeling issues that may explain the
low proposed exit level, and to look
more carefully at those constituents
where this issue only arises from the
4 When compared with mean soil background
levels provided by the USGS, the exit levels are not
more that 1 order of magnitude more restrictive.
modeling of risks from land application
units, to identify potential contingent
management solutions to this problem.
Finally, EPA requests comment on
whether these arguments could be
extended to site-specific determinations
where information on local background
constituent concentrations and form in
soil are available and have been
reviewed by a State regulatory authority.
EPA assumes that such an approach
would only apply if the background
concentrations were more than very
localized and the concentrations were
naturally-occurring rather than due to
past contamination. If a site-specific
determination were adopted, two
approaches are available that have been
used in other contexts. One statistical
technique for determining whether
background data conform to a normal
distribution assumption includes
combining the Student-t difference of
means test, presented in the Permit
Guidance Manual on Unsaturated Zone
Monitoring for Hazardous Waste Land
Treatment Units, (EPA, 1986) with the
normal tolerance interval approach
found in Statistical Analysis of Ground
Water at RCRA Facilities-Interim Final
Guidance, (EPA, April 1989). The
Student-t test compares averaged waste/
media concentrations to background
concentrations, and is used to determine
if the waste/media as a whole is within
a specified criteria. However, even if the
waste/media passes the Student-t test,
individual sample concentrations may
still exceed the tolerance interval limit.
The normal tolerance interval approach
is used to compare sample
concentrations to an upper tolerance
value based on the background mean,
standard deviation, and sample size.
If such an approach is incorporated
into the final rule, it would include
criteria for defining and collecting
adequate background samples. More
specifically, the facility would be
required to identify background
locations, sample size, soil depth, etc.
for at least four samples in a "difference
of means" demonstration, and six to
eight samples for a "tolerance of means"
demonstration. The facility would also
need to demonstrate the normalcy of the
sample distribution. The Agency would
require that this information be
included as part of the facility's
sampling and analysis plan and subject
to review by the appropriate overseeing
authority.
A more simplified approach would be
to establish exit levels at Vio of the
naturally occurring background level.
The rationale for using Vio is that these
levels would not appreciably contribute
to the overall risk posed by elevated
levels in the environmental media. EPA
requests comment of this approach as
well as the rationale..
Alternatively, the rule could defer any
background level demonstrations to an
omnibus authority for the overseeing
agency. Under this concept, a claimant
could submit information on naturally
occurring background level and a
request for modified exit levels to the
agency overseeing the exemption
process, which would have discretion to
grant modifications where they are
clearly justified. Comment is requested
on the need for this authority. >
The Agency solicits comments on
other appropriate and generic ways (1)
to identify background levels in soils,
and (2) to incorporate the existing 40
CFR part 264, subpart F standards for
establishing background levels for
groundwater. Other suggestions that
address the Agency's intent to
promulgate a simplified exemption with
little reliance on site-specific
considerations but also allow for
consideration of elevated background
levels will be considered.
EPA also observed that some of the
exit levels for organic chemicals appear
relatively high (see, for example, the
level for xylene). EPA believes that
these results occurred primarily because
these chemicals either are toxic only at
relatively high concentrations or
undergo high dilution during transport.
EPA, however, requests comment on
whether these chemicals are frequently
co-disposed and; if so, whether they
might pose cumulative risks not
assessed by the risk analysis. EPA is
interested in information on issues such
as whether a waste containing one or
more of these constituents at
concentrations near exit levels would be
ignitable or threaten the integrity of
control measures such as liners.
H. Constituents with Extrapolated Risk-
based Levels
EPA was unable to conduct the risk
assessment for 187 of the 376
constituents on the exit list. In most of
these cases, EPA was unable to find
acceptable human health benchmarks to
serve as the starting place for the
assessment. In a few cases, EPA could
not find values for critical physical or
chemical properties, such as log KOWS.
Based on its past experience, EPA
believes it would need at least a year to
develop a new human health
benchmark value for any constituent.
EPA has less experience with the type
of research and peer review needed to
develop values for physical and
chemical properties, but it believes that
this process also would be time-
consuming.
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Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66377
Rather than not consider the 187
constituents for which EPA was unahle
to conduct the risk assessment as
potential candidate constituents for exit
criteria, EPA developed an approach for
establishing exit criteria for these
constituents. The Agency grouped the
constituents on the exit list into classes,
based on chemical structure. EPA
selected the 50th percentile value from
the range of modeled risk levels for each
chemical class. This 50th percentile
value serves as the extrapolated risk-
based level for the un-modeled
constituents in the corresponding
chemical class. The constituents and
their 50th percentile extrapolated risk-
based levels are presented in a
background document Background
Document to Support the Methodology
used In Extrapolating Exit Levels to
Constituents ivith no Health-Based
Benchmarks. EPA is proposing the 50th
percentile level to avoid adding another
conservative assumption to the
derivation of exit levels for these
constituents. EPA believes that the
multipathway approach is already
sufficiently conservative to protect
human health and the environment
oven for these chemicals. EPA, however,
requests comment on the alternative of
using the 10th percentile or a different
percentile from the modeled exit levels
from each class. Such an approach
would reduce the chances that the
actual health benchmark for a particular
level was lower than the extrapolated
estimate. However, it would also
increase the odds that the extrapolated
level was higher than needed for many
constituents. A complete list of
extrapolated constituents and associated
risk levels may be found in appendix C
to today's preamble.
EPA recognizes that this approach to
generating exit levels is much less
sophisticated and precise than the
multipathway analysis. Nonetheless,
EPA prefers it to any of the available
alternatives. If EPA set no exit levels
and made wastes containing any of
these constituents ineligible for exit, a
significant number of waste streams
would probably be ineligible, even
though they may pose no significant
threat to human health and the
environment. EPA's RIA data shows that
some of these constituents, such as
Cyanide and Anthracene, are fairly
prevalent. Although other constituents,
such as those found in the commercial
chemical products on the P and U lists
of hazardous wastes, are not very
prevalent, they may be significant for
generators that manage multiple waste
streams in centralized wastewater
treatment plants. In the absence of
extrapolated exit criteria, a generator
would lose its opportunity to claim an
exit for an entire combined stream if any
of these constituents is found in the
waste stream. Furthermore, it would
take a long time to complete the work
necessary to conduct exposure pathway
assessments for any significant number
of these 187 constituents.
Alternatively, EPA could propose to
allow wastes to exit without testing for
constituents lacking modeled exit
levels. EPA, however, finds this
approach insufficiently protective,
especially when it can at least
approximate likely risk levels as
described above.
Finally, EPA considered the
alternative of basing exit levels for these
constituents on quantitation limits. As
explained below, EPA is proposing to
use EQCs as exit levels where they are
higher than a constituent's
multipathway or extrapolated exit level.
(EPA is also proposing that wastes with
such constituents meet the technology-
based LDR standards for those
constituents prior to exit.) EPA
considered using this EQC and LDR
approach for constituents lacking
multipathway levels. Such an approach
would actually produce more
conservative exit levels, because EPA
would not use extrapolated levels that
are higher than EQCs. EQCs (and
technology-based LDRs), however, are
not based on risk. EPA prefers the
extrapolated approach because it takes
into account the toxicity and fate and
transport of structurally similar
chemicals. EPA believes it would be
unreasonable to continue to regulate a
chemical because chemistry can detect
it, where the extrapolation described
above suggests that the chemical poses
no significant risks at the EQC level.
EPA finds the option of basing exit
levels on the extrapolation procedure
described above to strike a reasonable
balance between the goals of protecting
human health and the environment and
eliminating regulation of low-risk
wastes. EPA, however, requests
comment on all of the alternatives
described in this section.
I. Analytical Considerations
Some of the proposed exit levels
established by the risk assessment and
the extrapolation methodology are low.
In some cases, existing analytical
methods cannot routinely detect the
constituents at those levels. EPA is
proposing to cap these potential exit
levels with reasonable analytical
quantitation limits. The Agency is
proposing quantitation limits that
represent the lowest levels that can be
reliably measured within acceptable
limits of precision and accuracy during
routine laboratory operating conditions
using appropriate methods. These
concentrations are referred to as
"exemption quantitation criteria," or
EQCs. It is necessary to specify EQCs
because a number of the constituents on
the exemption list have either modeled
or extrapolated risk-based levels that are
not analytically achievable in all
matrices. Appendix C to today's
preamble lays out the comparison
between the modeled or extrapolated
risk level and the EQC for every
constituent. Approximately one-quarter
of the constituents have proposed
modeled or extrapolated risk-based
levels lower than EQC.
1. Development of Exemption
Quantitation Criteria (EQC)
To develop the EQCs proposed in
today's notice, EPA compiled a master
list of the quantitation limits published
for the identified constituents in the
Third Edition of Test Methods for
Evaluating Solid Waste, (SW-846),
including the first and second updates
(both of which are widely distributed
throughout the regulated community).
The Agency believes that the resultant
EQCs present achievable quantitation
limits for the proposed exemption
constituents in most matrices. The
Agency requests comment on the
proposed quantitation limits as well as
any data supporting those comments.
A regulatory action level (e.g., exit
levels) must provide a clear distinction
between those wastes subject to the
regulation and those excluded. Action
levels based on analytical
determinations within a methods
quantitative range can be used to
determine regulatory status with a high
degree of confidence. On the other
hand, when an analyte is present at a
concentration equal to the detection
limit (DL) it will be detected only half
the time. In other words there is a 50%
risk of a false negative result when the
analyte is present at the DL
concentration. There is, however, a less
than 1% risk of false positive results at
this level. Therefore, regulations set at
the detection limit would not identify
non-compliance reliably.
The Agency is in the process of re-
evaluating EQCs for some constituents.
Preliminary updated EQCs could not be
incorporated into today's proposed rule,
but have been included in the docket for
comment.
2. EQCs and LDR Requirements as Exit
Levels
A comparison of the modeled or
extrapolated risk-based levels with the
EQCs reveals a number of cases where
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66378 Federal Register / Vol. 60, No. 245 /Thursday, December 21, 1995 / Proposed Rules
quantitative measurement of analyte
concentration at the modeled or
extrapolated risk-based level cannot be
reliably achieved, using standardized
analytical methods. In today's proposed
rule, for wastes containing constituents
with a modeled or extrapolated risk-
based level lower than the EQC, exit
criteria include meeting the EQC along
.with an additional requirement that the
waste meet Land Disposal Restrictions
(LDR) treatment standards from part
268, regardless of whether or not the
waste is to be land disposed. The exit
table for constituents with EQCs as exit
levels is proposed appendix X of 40 CFR
part 261, Table B.
a. EQCs as exit levels
Only when the comparison between
the modeled or extrapolated risk-based
level with dial constituent's EQC level
reveals that the constituent cannot be
quantitated at the modeled or
extrapolated risk-based level, does the
EQC become the exit level. For example,
the modeled risk-based level for 2-
nitropropane in wastewaters is 0.00019
ug/L. The EQC for 2-nitrbpropane in
wastewaters is 0.0058 ug/L. 2-
nitropropane is listed in appendix X,
Table B, with an exemption level of
0.0058 ug/L. In other words, die
exemption level for 2-nitropropane has
been met if the claimant demonstrates
that the method used can achieve the
EQC of 0.0058 |ig/L in the waste matrix,
and the level detected by the method
does not exceed 0.0058 ug/L.
The Agency believes that, for those
constituents that have a modeled or
extrapolated risk-based level lower than
the achievable quantitation limit,
demonstration that the constituent is
not present above the EQC is the most
reasonable approach to setting a
national exemption level. The Agency is
proposing that quantitation limits cap
the modeled or extrapolated risk-based
levels because a reliable, consistent
measure of the constituent below the
quantitation limit is not achievable. By
establishing EQCs as benchmarks (or
maximum allowable quantitation
limits), the Agency is ensuring that all
exemption demonstrations will achieve
acceptable analytical sensitivity, and
that wastes with high levels of
contamination that tend to confound
analytical protocols are not exempted.
The Agency requests comments on
whether an exemption demonstration
should be considered adequate if all
proper method selection and QC
procedures are followed and the
constituents are not detected, even
though die EQC level has not been
analytically attained. This situation
could arise even in relatively clean
matrices if the constituents bind
strongly to the matrix or if the
constituents degrade rapidly during the
analysis. However, the Agency would
, not want the exemption to be allowed
if the EQC could not be achieved
because of interference from other
contaminants in the matrix, or if
inappropriate methodology, i.e., sample
preparation, cleanup (if necessary), or
determinative, was used.
EPA is not proposing that any exit
level based on an EQC can serve as a
"minimize threat" level capping current
40 CFR part 268 treatment standards.
Such levels are not sufficiently related
to a constituent's risk.
b. LDR Requirements for Constituents
Widi EQC Exit Levels
EPA considered the option of setting
exit levels for all constituents at their
modeled or extrapolated levels,
regardless of analytical considerations.
EPA also considered the alternative of
making wastes containing constituents
with analytical limitations ineligible for
exit. Both of these options, however, are
likely to constrain significantly die
number of waste streams eligible for
exit. Approximately one-quarter of the
constituents on the exit list have EQCs
above risk-based or extrapolated levels.
Some of these constituents, such as
Beryllium and Arsenic, are fairly
prevalent. For less prevalent
constituents, EPA has die same
concerns about limiting exit for wastes
managed in centralized wastewater
treatment systems that it described
above in the section on extrapolated risk
levels. Further, this approach would
overregulate wastes where constituents
were in fact below risk levels. EPA
prefers options which would not
prohibit all wastes with these
constituents from exiting.
The most promising alternative EPA
found was setting exit levels for these
constituents at EQC levels, and also
requiring all wastes containing these
constituents to comply with LDR
treatment standards, even where such
waste are not destined for land disposal.
This alternative offers the possibility of
additional risk reductions and,
therefore, reduces the possibility that
wastes posing significant threats will
escape Subtitle C control.
EPA is unable to characterize the
amount of additional risk reduction for
a number of reasons. First, as explained
in more detail in die Minimize Threat
section of the preamble, compliance
with LDRs already will be required after
exit before land disposal for all wastes
(except those that are below exit levels
at their point of generation). The LDR
requirement for constituents with EQC
exit levels may provide additional risk
reduction, even for those constituents
that are not managed in land disposal
units. EPA currently does not know how
frequently nonhazardous wastes are
burned as fuel, incinerated, or otherwise
managed outside of land disposal.
Additionally, the Universal Treatment
Standards (UTS) for nonwastewaters,
were developed based on similar
analytical chemistry considerations of
detection limits. The majority of the
UTS limits for nonwastewaters were
based, however, on analysis of residuals
from the treatment of what EPA
determined to be the most difficult to
treat wastes and, as a result, diis often
represented the most difficult to analyze
treated matrix (i.e., higher detection
limits than those represented by the
EQCs). The majority of die UTS limits
for wastewaters, on the other hand, were
not developed based on limits of
detection but rather they were based on
analysis of treated effluents regulated
under EPA's National Pollution
Discharge Elimination System (NPDES).
LDR requirements for all wastes
subject to the UTS would be equal to or
higher than the EQC exit levels
diemselves. However, for wastes subject
to treatment standards based on
application of specified treatment
mediods under § 268.40, extending LDR
requirements may provide additional
risk reduction.
EPA believes that the combined
approach of requiring non-detection at
EQC levels and compliance with LDR
standards for all waste streams,
regardless of whether or not the waste
will be land disposal, offers a reasonable
balance between the goals of reducing
overregulation and ensuring that wastes
with significant risks remain subject to
Subtitle C. EPA, however, requests
comment on all of the alternatives
described above. EPA- also requests
comment on the option of basing exit
levels for these constituents on EQCs
alone and relying on continued,
independent applicability of LDR
requirements for wastes that exit and are
destined for land disposal.
3. Exemption for Constituents Without
EQCs
There are several constituents covered
in today's notice for which EQCs could
not be developed. The universe of these
constituents includes 78 constituents,
most of which are not widely prevalent
in wastes. Most are also found only in
P and U listed wastes. These
constituents are listed in table B to
appendix X without associated
exemption levels. The background
document Background Document to
Support the Development of Exemption
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Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66379
Quantitation Criteria (EQCs) and
Description of Analytical Methods
under the Waste Exit Rule explains why
EQCs could not be created.
EPA is proposing that wastes
containing these constituents (i.e.,
whore an applicant has not documented
that those constituents are not present—
see section VHI.A.l.b.,) may remain
eligible for an exemption under today's
proposed rule by complying fully with
LDR treatment standards applicable to
the waste, as codified in 40 CFR part
268, regardless of whether the waste is
to be land disposed. The Agency
believes that any potential risks posed
by these constituents are likely to be
further reduced by applying LDR
standards from part 268 to the waste,
before the waste may be exempt,
regardless of whether or not the waste
is destined for land disposal. The
Agency asks for comment on this
approach.
An alternative approach would be to
allow wastes with these constituents to
exit without additional LDR obligations,
but relying on continued, independent
applicability of LDR treatment
requirements to wastes destined for land
disposal only. Another approach would
be to prohibit wastes containing these
constituents from being eligible for
exemption under today's proposed rule.
An additional approach would be that
these constituents could be deleted from
the exit table. The Agency requests
comment on each of these alternatives.
EPA is not willing to propose to use
LDR standards as exit levels for any
other group of constituents. The
technology-based LDR standards are not
based on any risk assessment. A
comparison of these standards with the
mulUpathway risk levels that EPA
produced shows that the LDR standards
are sometimes more stringent and
sometimes less stringent than risk-based
levels. EPA believes that it is more
prudent to base exit levels on risk
assessment where possible because this
better assures protection of human
health and the environment. EPA views
use of the LDR standards as the option
of least preference, but necessary for
exit for this group of constituents. EPA
is willing to consider it only where
there is no alternative to prohibiting a
constituent from being eligible for exit.
V. Presentation of Exit Levels
Today's proposed exemption criteria
involves setting exemption levels for
toxicants in listed waste, and in some
cases requiring additional compliance
with the requirements set forth at 40
CFR part 268. To exit Subtitle C
regulation as a listed hazardous waste,
all the hazardous constituents listed in
appendix X of part 261 would be
required to be in concentrations less
than, or equal to the numeric exit levels
and when specified, the waste would
have to meet the applicable
requirements at 40 CFR part 268.
Appendix C to the preamble presents
constituents, distinguishes between
modeled and extrapolated constituents,
and includes EQCs for each constituent.
A. Constituents With Modeled or
Extrapolated Risk-Based Exit Levels
The Table A of proposed appendix X
to part 261 presents exit levels for
constituents with modeled or
extrapolated risk-based levels which can
be reliably quantified. See section IV.H.
for a description of how this was
determined. Listed hazardous waste
would be required to contain
concentrations at or below the specified
exit levels to be eligible to be exempted
from Subtitle C requirements other than
LDR. In some cases we are proposing to
change the land disposal restriction
requirements at 40 CFR part 268 as well.
A totals analysis would be required for
both wastewaters and nonwastewaters
to show that the constituent does not
exist in the wastestream at levels above
the exemption level.
For nonwastewaters, the Agency is
also proposing that generators either use
the TCLP test or a calculational screen
to measure or calculate constituents'.'
leachate from wastes. If the TCLP test
shows leachate concentration in the
waste is below the leach exit level, the
waste would be considered to not pose
a hazard to groundwater.
The Agency has in the past
experienced difficulty in using the
TCLP test for some types of waste. The
Agency solicits comment on how to
consider oily wastes and other wastes
that are difficult to filter in the TCLP
test or whose impact on groundwater is
believed to be underestimated by the
TCLP (such as materials subject to non-
aqueous phase transport). Comment on
alternative tests for these wastes, as well
as comment on how to define such
wastes for regulatory purposes is sought.
A more complete discussion of oily
waste can be found in VIII.A.l.a.iv.
Table A of appendix X of 40 CFR part
261 presents results of two alternatives
for establishing the exit levels. These
alternatives differ only in the
benchmark used to calculate the
modeled risk-based levels. For certain
constituents there exists both a risk-
based toxicity benchmark and a
maximum concentration level (MCL)
established under the Safe Drinking
Water Act (SDWA). These numbers may
differ because the'MCLs are established
using some non-risk considerations
such as the cost of treatment and the
availability of technology and consider
exposure contributions from other
sources for non-carcinogens. See section
IV.D. of today's proposal for a complete
discussion of toxicity benchmarks and
MCLs.
B. Constituents With Quantitation-
Based Exit Levels; Table B to Appendix
X
Table B of proposed appendix X to
part 261 presents quantitation-based
exit levels for constituents with
methods that cannot reliably quantify
the modeled or extrapolated risk-based
levels. All exit levels on Table B of
appendix X to 40 CFR part 261 are
based on EQCs. (See section IV.I.)
Wastes containing any of these
constituents must also comply with the
applicable treatment standards set forth
at 40 CFR part 268, the Land Disposal
Restrictions (LDR) in order to meet
today's proposed exemption, regardless
of whether or not the waste is to be land
disposed.
Some constituents on Table B of
appendix X of 40 CFR part 261 do not
have associated exit levels. Waste with
these constituents may exit only after
complying with the LDR treatment
standards for the waste. (See section
C. How To Read the Exit Level Tables
For a waste to be eligible to exit
Subtitle C under the exit proposed in
today's rulemaking, every constituent in
the waste must be below its exit level.
Proposed appendix X of 40 CFR part
261, Tables A and B are the exit
constituents and the exit levels. The
following is a description of how to read
the tables.
• The constituent list is derived from
constituents listed in appendix VII,
Basis for Listing Hazardous Waste;
Appendix VIII, Hazardous Constituents;
and appendix IX of part 264, the
Ground- Water Monitoring List. (See
section IV.C.)
• Table A represents constituents and
their risk exit values — where the risk
values can be measured analytically.
(See sections IV.E., and IV.I.)
• Table B represents constituents
with quantitation limits (EQCs) as exit
levels — where the constituent cannot be
measured at the modeled or
extrapolated risk value. An additional
condition of exit, compliance with
treatment standards in 40 CFR part 268,
exists for any waste becoming exempt
under today's rulemaking by using a
constituent exit level on Table B. (See
section IV.I.2.b.)
• There will be overlap for some
constituents between Tables A & B. For
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66380 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 /Proposed Rules
example, the wastewater exit level for a
constituent may be on Table A, whereas
the nonwastewater exit level may be on
Table B.
» Where an exit level does not exist
on Table A or B for a particular
constituent, the waste need not be tested
for that constituent. For example, some
constituents that are hydrolyzers have
exit levels for nonwastewaters, but not
for wastewaters. A complete discussion
of deletions to the master constituent
list can be found in section IV.C.
The tables' columns:
• Columns 1 and 2 are the CAS
numbers & constituent names.
• There are two proposed options for
the development of today's proposed
exit levels. Option 1 is the option
whereby Maximum Contaminant Levels
(MCLs) from the Drinking Water
program are used as an acceptable
toxicity exposure for human drinking
water exposure and toxicity benchmarks
are used for other exposures. Option 2
is the option whereby toxicity
benchmarks are used as acceptable
exposure levels for all exposures. A
more complete discussion of these two
options is found in section IV.D. of
today's proposed rule. The effect of co-
proposing these two options is that
there are two independent sets of
proposed exit levels.
— Columns 3,4, and 5 represent the exit
levels that were derived by using an
MCL benchmark for drinking water
ingestion & using toxicity benchmarks
for all other routes of exposure.
— Columns 6, 7, and 8 represent the exit
levels that were derived by using
toxicity benchmarks for all routes of
exposure.
• The definitions of wastewater and
nonwastewater are discussed in
• Columns 3 & 6 represent
wastewater exit values. If a generator
determines he/she has a wastewater, if
each constituent in the waste meets
these wastewater exit levels, it is
eligible for exemption.
— Values in columns 3 & 6 were derived
from the most limiting of non-
groundwater-ecological receptor, non-
groundwater-human receptor, and
groundwater pathway values from
surface impoundments and tanks (the
risk assessment's wastewater units).
» Columns (4 and 5) and (7 and 8)
represent nonwastewater exit values. If
a generator determines he/she has a
non-wastewater, if each constituent in
the waste meets both of these
nonwastewater values, it is eligible for
exemption. 'The totals level must be met
by a totals analysis. The leach level
must be met by a TCLP test or the
calculational screen.
—Values in columns;4 & 7 were derived
from the most limiting of the non-
groundwater-ecological receptor and
non-groundwater-human receptor -
pathway values from land application
units, ash monofills, and waste piles
(the risk assessment's nonwastewater
units).
—Values in columns 5 & 8 were derived
from the most limiting of the
groundwater pathway values from
land application units, landfills, and
waste piles (the risk assessment's
nonwastewater units).
VI. Minimize Threat Levels
A. Background
1. Summary of the Hazardous and Solid
Waste Amendments of 1984 ,
The Hazardous and Solid Waste
Amendments (HSWA), enacted on
November 8,1984, allow hazardous
wastes to be land disposed of only if
they satisfy either of two conditions: (1)
They can either be treated or otherwise
satisfy the requirements of section
3004(m), which requires EPA to set •
levels or methods of treatment, if any,
which substantially diminish the
toxicity of the water or substantially
reduce the likelihood of migration of
hazardous constituents from the water
so that-short term and long term threats
to human health and the environment
are minimized; or (2) they can be land
disposed in units satisfying the so-
called no migration standards in
sections 3004(d)(l), (e)(l), and'(g)(5).
Land disposal includes any placement
of hazardous waste in a landfill, surface
impoundment, water pile, injection
well, land treatment facility, salt dome
formation, underground mine or cave.
See RCRA section 3004(k).
EPA was required to promulgate land
disposal prohibitions and treatments
standards by May 8,1990 for all wastes
that were either listed or identified
hazardous at the time of the 1984
amendments, a task EPA completed
within the statutory time frames. See
RCRA section 3004(d), (e), and (g). EPA
is also required to promulgate
prohibitions and treatment standards for
wastes identified or listed after the date
of the 1984 amendments within six
months after the listing or identification
takes effect. See RCRA section
3004(g)(4).
The land disposal restrictions are
effective on promulgation. See RCRA
section 3004(h)(l). However, the
Administrator may grant a national
capacity variance fronj the effective date
and establish a later effective date (not
to exceed two years) based on the
earliest date on which adequate
alternative treatment, recovery, or •
disposal capacity that protects human
health and the environment will be
available. (RCRA section 3004(h)(2).)
The Administrator may also grant a
case-by-case extension of the effective
date for up to one year, renewable once
for up to one additional year when an
applicant(s) successfully makes certain
demonstrations. (RCRA section
3004(h)(3).) See 55 FR 22526 (June 1,
1990) for a more detailed discussion on
national capacity variances and case-by-
case extensions.
As explained in the legislative
history, the purpose of the land disposal
restrictions is to reduce the risks
associated with land disposal. Congress
also intended the restrictions to reduce
reliance on land disposal and promote
waste minimization since land disposal
was its least favored method of
managing hazardous wastes.
2. EPA's Interpretation of Standard for
Treatment Requirements
The heart of the LDRs are the
standards for treatment prior to land
disposal, which must meet the statutory
requirement to "substantially diminish
the toxicity of the water or substantially
reduce the toxicity of the waste so that
short term and long term threats to
human health and the environment are
minimized." RCRA Section 3004(m):
EPA's interpretation of this "minimize
threat" requirement has evolved
through a long series of rulemakings.
When EPA proposed its first set of
LDR treatment standards it took the
position that the most effective way to
minimize threats was to base standards
on the capabilities of generally available
treatment technologies. (51 FR 16011
(January 14, 1986).) To avoid
unnecessary treatment, however, EPA
also proposed to "cap" the technology
based standards with risk-based
screening levels based on human health
toxicity thresholds for individual
hazardous constituents and modeling of
the groundwater route for exposure. (51
FR 16011-13.)
In the final rule EPA promulgated
only the technology based standards. ,
EPA explained that although it believed
it had authority to promulgate risk-
based standards, it was not
promulgating the proposed risk-based
caps because of extensive comments
raising concerns about the scientific
uncertainties of risk analysis. (52 FR
40578 (November 7,1986).) Industry
challenged the final standards, claiming
that they required treatment to
concentrations below "minimize threat"
levels. On review, the Court held that
section 3004(m) authorized both •
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Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66381
technology based and risk-based
standards, but remanded the rule to EPA
for a fuller explanation of its decision to
rely on technology-based standards
alone. (Hazardous Waste Treatment
Council v. EPA, 886 F. 2d 355 (D.C.
Giro. 1989). ("HVVTC HI").) The court
also held that EPA was not obligated to
adopt either the RCRA characteristic test
levels or the Safe Drinking Water Act
Maximum Contaminant levels (MCLs)
as "minimize threat" levels because
neither "purports to establish a level at
which safety is assured or 'threats to
human health and the environment are
minimized'." (886 F. 2d at 363.)
In its response to the remand, EPA
stated that the best way to fulfill the
requirements of section 3004(m) would
be to ensure that no technology-based
treatment standard required treatment of
hazardous waste containing levels of
hazardous constituents posing
insignificant risks. (55 FR 6641 (Feb. 26,
1990).) EPA, however, explained that it
was not yet able to promulgate such
levels, EPA believed that it lacked a
reliable predictive model for ground-
water exposure, needed to assess
exposure scenarios for air pathways,
needed to consider impacts on
ecological receptors, needed to develop
additional analytic methods for
hazardous constituents, and needed to
develop an approach for constituents
with threshold effect levels lower than
detection limits. (Id. at 6642.)
In the same notice, EPA noted that the
"minimize threat" language of section
3004(m) could reasonably be interpreted
to require more protection than the
"normal subtitle C command that
standards be those necessary to protect
human health and the environment."
(Id. at 6641.) EPA found that the many
portions of the 1984 amendments
stressing the inherent uncertainties of
land disposal buttressed this
interpretation. See, e.g., RCRA sections
1002(b)(7), 3004(d)(l)(A), 3004(e)(i)(A),
3004(g)(5). EPA also found support in
the legislative history. For example, the
Senate amendment containing the
"minimize threat" standards replaced a
committee bill that only would have
required treatment to be "protective of
human health and the environment."
See S. 757, section 3004(b)(7), printed at
S. Pep. No. 284, 98th Cong., 2nd Session
86. Further, EPA noted that the "no
threat" levels it had been using in site-
specific and waste stream specific
contexts, such as clean closures,
delistings, and no-migration petitions,
would not necessarily be appropriate for
generally applicable standards required
to minimize threats to health and the
environment. (55 FR 6641, note l.)
At the same time, EPA took the
position that section 30004(m) does not
require the elimination of every
conceivable threat posed by land
disposal of hazardous waste, citing a
statement by Senator Chafee that "[i]t is
not intended that every waste receive
repetitive levels of treatment, nor must
all inorganic constituents be reclaimed."
130 Cong. Rec. S.9179 (daily ed., July
25,1984). (55 FR 6641, note 1.) Clearly
EPA did not interpret the minimize
threat language to require the
elimination of all threats.
Today, the Agency is proposing to re-
evaluate the basis for some of the
existing performance standards
established for listed wastes. Since
EPA's response to the HWTC III remand
in 1990; the state-of-the-art in making
quantitative determinations of risk has
advanced and available methods have
improved significantly. In addition, the
increased sensitivity of analytical
methods has lowered achievable
detection limits, better bioassays exist
than in the past, and more extensive
biological data is available for
extrapolation. As a result, the universe
of available health-based and ecological
data has grown significantly, and the
reliability of this information has
improved. The Agency now believes
that these data can be used to establish
levels that minimize threats to human
health and the environment.
B. Risk Assessment and Minimize
Threat Levels
1. Rationale
a. Overview
Today the Agency is proposing to
establish risk-based LDR treatment
requirements for some of the hazardous
constituents for which exit levels are
being proposed. These risk-based LDR
requirements will minimize the short-
term and long-term threats to human
health and the environment posed by
the hazardous waste constituents. The
risk-based LDR levels (or "minimize
threat" levels) would have the effect of
capping, or limiting, treatment of those
waste constituents where the current
technology-based UTS standards require
lower concentrations. EPA also hoped to
propose most of these constituent-
specific levels as "minimize threat"
levels under section 3004(m) of RCRA
that would cap current technology-
based treatment standards under at
these levels the LDR program. However,
EPA is proposing "minimize threat"
levels only for those constituents that
were evaluated under the multipathway
risk analysis and are not capped by
quantitation (EQC) limitations. EPA is
proposing to promulgate such levels as
replacements for the constituent-
specific treatment levels in the LDR
Universal Treatment Standards (UTS).
(As explained in more detail in Section
VI, EPA is not proposing to cap any LDR
standards requiring the use of specified
technologies.) As shown on Table 1,
§ 268.60, EPA is proposing "minimize
threat" levels to cap UTS treatment
requirements for either the wastewater
or nonwastewater (or both) for
approximately 70 wastewater
constituents and 90 nonwastewater
constituents.
EPA, however, is not proposing that
any extrapolated levels serve as
"minimize threat" levels for LDR
purposes. EPA does not have as much
confidence that this alternative
methodology provides enough
information on risks to human health
and the environment to enable EPA to
determine that risks have been
minimized. Similarly, EPA is not
proposing that any levels based on
quantitation limits serve as "minimize
threat" levels. Such levels are not based
on any analysis of risks to human health
and the environment. In fact, as
explained above, EPA is proposing to
require compliance with technology-
based LDR standards for all wastes
which contain such constituents.
If a claimant finds that all
constituents in a waste are below exit
levels at the waste's point of generation
and if the claimant meets all of the
requirements for filing an exit claim,
EPA will not require compliance with
the LDR treatment standards for the
waste. EPA will take the position that
such as waste never became subject to
subtitle C regulations, so that LDR
standards never applied to the waste.
EPA is proposing to take this position
for all exit levels, regardless of whether
they were generated by the
multipathway analysis, the
extrapolation method, or EQC
limitations. For further explanation, see
section VI.D.
EPA, however, is proposing that all
listed wastes which as generated
contain constituents exceeding exit
levels must meet LDR requirements
(current or as modified by this
proposal), even if the waste
subsequently becomes exempt from
hazardous waste regulation under this
rule. This requirement resembles EPA's
current rules for "de-characterized"
wastes, which must meet LDR
requirements even after they cease to
exhibit the hazardous characteristic that
made them subject to Subtitle C in the
first place.
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66382 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
b. "Minimize Threat" requirement of
Section 3004(m)
EPA continues to believe that the
minimize threat language of section
3004{m) does not require the
elimination of every conceivable threat
posed by land disposal of a hazardous
waste. The legislative history of LDR
indicates that Congress did not intend to
require wastes to undergo repetitive or
ultimate levels of treatment. Rather,
Congress wanted to require use of
effective, but widely available treatment
technologies. See 130 Cong. Rec. S 9178
(daily ed. July 25,1984) (statement of
Senator Chafee introducing the
amendment that became section
3004(m).)). Requiring elimination of all
conceivable threats would almost
certainly require use of the most
effective treatment methods available,
and this appears to conflict with
Congresses' treatment goals. Moreover,
although the DC Circuit has cited the
dictionary definition of "minimize" to
uphold technology-based treatment
standards below EPA standards such as
MCLs and TC levels, EPA does not
believe that the court meant that EPA
literally must reduce threats to the
maximum extent possible. (See
Hazardous Waste Treatment Council III,
886 F.2d at 361; Chemical Waste
Management II, 976 F 2d. at 14.) EPA
notes that the court indicated that risk-
based treatment standards would satisfy
section 30004(m). Hazardous Waste
Treatment Council III, 866 F.2d at 364-
65. Further, in his concurring opinion,
Judge Silberman stated that Congress
would allow EPA to exercise reasonable
amounts of discretion in determining
the level of risk reduction needed to
meet the minimize threat requirement.
Id. at 3 72.
The Agency believes that today's exit
concentrations can serve as risk-based
land disposal restriction levels for
several reasons. First, the risk
assessment, described in Section IV of
today's proposal, significantly expands
beyond the scope of past Agency risk
assessment for wastes and waste
constituents. Where adequate data are
available, the analysis can evaluate the
potential for waste constituent
migration through almost all significant
environmental fate and transport
pathways leading to exposure for
human and ecological receptors. As
explained in more detail below, the
Agency is also relying on reasonable
conservative risk targets for both
humans and ecological receptors in
developing this risk assessment. The
Agency believes that the proposed exit
levels represent levels below which
further treatment would not be needed
to minimize threats to human health
and the environment.
c. Scope of Risk Assessment
The broad scope of the risk analysis
is a critical factor in the Agency's
conclusion that proposed exit levels
minimize both short term and long-term
threats to human health and the
environment, for those constituents
where data are relatively complete.
The risk analysis evaluates all of the
most common non-Subtitle C disposal
options available to waste generators
and treaters. These include disposal in
landfills/monofills and by land farming,
and management in surface
impoundments, tanks and waste piles.
The risk analysis assumes no minimum
level of regulation of these facilities, and
relies on available data to characterize
them. As described in detail in Section
IV and in the risk analysis report (EPA
1995), EPA modeled each disposal
alternative using median values for most
inputs, and high-end or conservative
values for the two fate and transport and
two exposure parameters for which the
modeling outcome is most sensitive.
The Agency believes that the modeling
will also protect against exposures from
similar disposal alternatives not
specifically modeled.
The risk analysis evaluates the
movement of waste constituents from
each of these disposal options through
numerous environmental fate and
transport pathways. These include
pathways involving volatiles and
respirable (PM10) particulates,
particulate deposition on soil and plant
surfaces, vapor phase diffusion into
surface water and plants, and surface
run-off and soil erosion. Many of these
pathways can result in waste
constituent movement through the food-
chains. Therefore, human exposures
resulting from these fate and transport
pathways include inhalation, soil or
groundwater ingestion, and dermal
contact, as well as exposure through
consumption of contaminated foods
such as fish, beef or vegetables.
EPA screened all multipathway
constituents for potential to pose threats
to ecological receptors. For 45
constituents, EPA quantitatively
assessed likely risk to selected
ecological receptors. Risks to both fresh
water aquatic and terrestrial organisms
were evaluated, representing different
trophic levels and feeding habits of the
ecosystem. Fish, daphnids, and benthic
organisms, mammals, birds, plants, and
soil organisms (nematodes, insects, etc.)
were evaluated. The sustainability of the
ecosystem and reproducing populations
within the aquatic and terrestrial
ecosystems was selected as an
assessment endpoint, as described in
Section IV of this Notice and in detail
in Chapter 3 of the risk analysis support
document (EPA 1995).
In addition, as part of this overall risk
assessment effort, the Agency has
reviewed and reevaluated its modeling
of waste and waste constituent
movement through groundwater. As
described in Section IV above, this
responds to comments by interested
parties on the original HWIR proposal,
as well as incorporates additional data
submitted to the Agency (API data base),
and updated modeling of leaching from
wastes (new HELP model; get Cite).
In evaluating groundwater, the
Agency examined both wells located on
the landfill edge and closest wells .
anywhere down-gradient. Also, both
finite source type and infinite-source
type constituents (which behave as
though there is an infinite supply of the
constituent in the landfill, and will
continue to leach forever) were
evaluated. For'finite source type
constituents, the available constituent
was not apportioned over the
groundwater and other pathways, i.e.,
groundwater was modeled separately.
Adsorption to soil and degradation of
waste constituents (but not
biodegradation) is modeled, and the
toxicity of constituent daughter
products (either more or less toxic than
the parent compounds) is included.
(There is a biodegradation module to the
model; however, data to run that
module for national conditions are not
adequate at this time, although data
were available for some sites. The
Agency will continue to evaluate
biodegradation data as they become
available, and assess in the future
whether national biodegradation
estimates can be defensibly made).
Leaching and groundwater migration
from disposal in unregulated industrial
landfills, surface impoundments, and
waste piles have been modeled.
In evaluating the results of this series
of groundwater modeling exercises, the
Agency selected the approximate 90th
percentile from a distribution of wells
closest to modelled sites. This means
that there is about a 90% probability
that the drinking water well closest to
the landfill would be protected at the
target concentration (MCL or HBN). All
wells more distant would be protected
to a greater extent.
As described in section VLB. above,
the Agency then reviewed the risk
assessment for groundwater and the
pathways for each constituent, and
selected as the exit level the
concentration, back-calculated to the
waste, from the most limiting (or highest
risk) pathway. By using the most
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limiting pathway as the basis for the risk
criterion, the Agency believes it has
accounted for all significant risks
resulting from disposal and
management of the waste outside of
Subtitle C.
The agency believes it is also
important to identify and discuss some
of the limitations of the risk assessment,
especially as they relate to determining
whether short term and long-term
threats to human health and the
environment have been minimized.
The analysis does not account for
additivity of risk for exposure to
multiple constituents. Evaluation of risk
additivity can be a complex analysis
when even a few constituents are
included. In the case of multiple waste
constituents, potentially occurring in
one or more waste streams that might be
considered for exit, the complexity of
conducting and analysis of additivity of
risk quickly becomes overwhelming.
However, EPA believes it will often be
the case that one constituent typically
drives determinations of whether waste
streams exit and additivity would often
make little difference with respect to the
calculated exit levels.
Exposures to the same constituent
from several pathways also are not
added together, even though the risk
analysis does apportion the available
quantity of waste constituents over the
different pathways evaluated. Again,
EPA believes that often one result (in
this case, one pathway) would
contribute most of the risk and little
would be gained from adding across
pathways. EPA requests comment on
this issue.
Data also were not available for all
human exposure routes for all
constituents, although data for high-risk
pathways were usually available.
Nonetheless, the Agency believes the
exit levels can be considered to
represent levels that minimize threats to
human health and the environment
because of the comprehensive
evaluation of possible exposure routes,
consideration of both human and
ecologic risk, selection of the most
restrictive pathway overall, and the
relatively conservative risk target, 10 ~6,
used in setting the exit levels derived
from cancer risk estimates.
As mentioned above, EPA conducted
a screening analysis to identify 47 high
priority constituents for ecological
assessment. EPA did not model the
ecological impacts for 36 additional
constituents that displayed one
characteristic indicating potential
ecological impacts. EPA is proposing to
set minimize threat levels for 19 of these
constituents.
EPA believes that it has adequately
assured that the caps to BDAT treatment
standards proposed/today minimize
threats to the environment. The specific
ecological risk assessment conducted for
45 constituents (19 of which have
minimize threat levels under this
proposal) is the most extensive EPA has
ever conducted under the RCRA
program to date. EPA did not find
threshold effects data for all seven
groups of ecological receptors for any
constituent evaluated for ecological
risks. Rather, EPA typically had
benchmarks for three to five groups.
Nevertheless, its consideration of a
broad range of species and use of
reasonably conservative endpoints
ensures that threats to ecological
receptors are minimized.
With regard to chemicals that did not
undergo this detailed assessment, EPA
has conducted an extensive review of
risks to human health, including a
thorough review of risks posed by
indirect pathways and risks posed by
constituents that bioaccumulate in
plants and animals consumed by
humans. (Bipaccumulation is a key
concern for protection of many
ecological species.) EPA believes that it
is reasonable to assume that the exit
levels identified by this analysis also
minimize threats to ecological receptors
unless it has some definite data
indicating that additional protection is
warranted. Reliance on these levels is
particularly appropriate for those
chemicals that did not display one of
EPA's ecological screening
characteristics. EPA finds it also
appropriate for the 15 "minimize
threat" chemicals which exhibited one
ecological screening characteristic. EPA
acknowledges that conducting a specific
assessment of ecological risks for these
15 constituents would have provided
additional assurance that threat to
ecological receptors were minimized.
EPA solicits comment on the option of
declining to set minimize .threat levels
for these 15 constituents until it can
complete an ecological assessment for
them.
d. Risk Targets Minimize Threats
The Agency believes that the risk
targets used in the risk analysis to back
calculate to waste concentrations
minimize threats to human health and
the environment. For cancer risks to
human, a risk target of one in one
million, over a lifetime is the risk target.
For non-carcinogens, a hazard quotient
(HQ) based on a reference dose or other
comparable value from the literature
could not exceed one (hazard quotient
(HQ)=1). Reference doses or comparable
values are based oh studies of toxicity
and no-effect,levels in test animals and
extrapolated, using safety factors, to
humans. For ecological receptors,
population effects inferred from
individual effects and effects on a
substantial number of both aquatic and
terrestrial species were evaluated.
Other risk targets may be considered
in establishing minimize threat levels.
The Agency solicits comment on
whether apportionment of the RfD ought
to be used in establishing minimize
threat levels (i.e., HQ<1). The Agency
uses 20% of the Rfd in setting drinking
water standards; a similar approach
might be appropriate in establishing
minimize threat levels and in
establishing exit levels. EPA requests
comment on this issue.
2. Public Policy Considerations
Finally, the Agency believes that it •
represents good public policy to reduce
or eliminate unneeded or duplicative
regulatory requirements. In this case,
the Agency believes that for the initial
list of constituents listed in Table 1 of
40 CFR 268.60, treatment to the UTS/
LDR standard is no longer required
beyond waste constituent
concentrations where risks to human
health and the environment are
insignificant. Because there is no
purpose in terms of protecting human
health and the environment for
retaining the more stringent LDR
requirements, the Agency is proposing
to revise them to the risk-based levels.
This would reduce the overall number
of different and distinct regulatory
requirements on waste generators and
treaters, would rationalize the RCRA
regulations, and will provide significant
pollution prevention opportunities and
incentives. Waste generators would
have only one target level to direct their
pollution prevention effort toward. If
generators met the LDR/exit levels, the
waste would not be considered
hazardous, and no additional treatment
would be required before disposal in a
subtitle D facility. Where waste
continues to exceed one or more exit
levels after LDR requirements are met,
subtitle C disposal would be required.
C. Risk-based LDR Levels
1. List of Constituents and Minimize
Threat Concentrations
As was mentioned earlier in this
section, only modeled constituents' risk-
level results are eligible to serve as risk-
based LDR levels meeting the statutory
requirement of minimize threat. In
addition, minimize threat levels are
only proposed for those constituents
where the risk level is higher (less
stringent) than the associated
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technology-based treatment standard in
§ 268.40 or the UTS level in § 268.48.
First, the Agency repeats that it is not
proposing to set any alternative risk-
based LDR standards expressed as
specified technologies (rather than
constituent concentrations.)
Consequently, the option of complying
with minimize threat levels in lieu of
levels specified in part 268 will be
available only for wastes with treatment
standards expressed as constituent
concentrations. This includes both
wastes subject to waste-specific
treatment requirements under the table
to § 268.40 and wastes subject to the
Universal Treatment Standard levels in
the table to § 268.48
The Agency proposes that for
purposes of establishing nonwastewater
and wastewater minimize threat values
for wastes with BDAT treatment
standards expressed as constituent
concentrations, the levels proposed
would utilize the LDR definitions of
nonwastewater and wastewater from 40
CFR 268.2(d) and (f). Therefore, any exit
levels that are considered
nonwastewater for purposes of exit will
also be considered nonwastewater for
purposes of minimize threat. Likewise,
wastewater exit levels will be
considered wastewater LDR levels. The
Agency believes that consistent
definitions of nonwastewater and
wastewater is the only practical means
to establish minimize threat levels. The
Agency realizes, however, that the
modeling and subsequent development
of exit levels for today's proposed exit
did not use the part 268 definition of
nonwastewater and wastewater. (A
complete discussion of this may be
found in section VIII.A.l.a.ii.) The effect
of this would be that some wastes that
would be defined as wastewaters under
today's proposed exit scheme would be
considered LDR non-wastewaters. The
Agency requests comment on whether
the definition in Part 268 should be
adopted for purposes of establishing
minimize threat levels.
The Agency compared the exit levels
to the current LDR treatment levels to
determine whether a constituent's risk
level should be proposed as a minimize
threat level. For wastewater values, the
LDR wastewater value was directly
compared to the wastewater exit value.
Where the UTS nonwastewater level is
a total level, the comparison was made
to the nonwastewater totals exit level.
Where the LDR nonwastewater level is
a leach level, the comparison was made
to the nonwastewater leach exit level.
However, for the reasons explained
below, the nonwastewater minimize
threat level would contain both a leach
level and a totals level. For both
wastewater and nonwastewater, where
the most comparable exit level is higher
(less stringent) than the current LDR
level, the constituent's risk level is
proposed as an optional minimize threat
level. The Agency requests comment on
this approach to determining which exit
levels are higher than current LDR
levels.
The Agency is proposing that testing
requirements when using minimize
threat levels would be consistent with
the current LDR testing requirements
found in § 268.7. The Agency proposes
that if a claimant wishes to meet LDR
requirements by complying with a
minimize threat level, the claimant must
meet the minimize threat levels with a
totals analysis, and where specified, the
waste must meet the leach level with a.
leachate analysis. The Agency believes
that a totals analysis is preferable to a
leach analysis for establishing minimize
threat levels, as it more directly pertains
to all pathways, not only the
groundwater pathway.
Today's proposed exit levels for
nonwastewaters consist of two risk
levels for each constituent. The totals
(mg/kg) nonwastewater risk level is the
result of the most limiting non-
groundwater pathway. The leach (mg/L)
nonwastewater risk level is the result of
the most limiting groundwater pathway.
The Agency believes it would be
preferable to have one exit level, but the
groundwater model results are a leach
(mg/1), whereas the results from the
multipathway analysis are a totals (mg/
kg), and the science to extrapolate from
a leach to totals is highly variable. Using
only the leach or only the total risk level
would reflect only a'portion of the risks
presented by the waste. A waste must
meet both of these limits before it
minimizes threats to human health and
the environment. Consequently, EPA is
proposing to include both levels in the
minimize threat standards for
nonwastewaters. The Agency proposes
to allow generators to either use a
calculational screen or perform the
TCLP to make a determination that
constituent concentrations do not
exceed nonwastewater leach minimize
threat levels. A full discussion and
explanation of the calculational screen
can be found in section VIII.A.l.a.iii. of
today's proposal.
Because extrapolating from a leach to
a total varies with each constituent and
is not easily measured, EPA has not
directly compared both of the minimize
threat levels with the LDR standard. The
Agency requests data on specific
constituents where the second, less
easily-compared nonwastewater
minimize threat level may be harder to
achieve than the current LDR standard.
If such results occur, waste handlers •
will not be required to use the new "
minimize threat levels. The levels in the
tables to § 268.40 and § 268.48 will
continue to satisfy LDR requirements as
they always have. The minimize threat
levels will be located in Table 1 of
§ 268.60, are optional, and are intended
to be used to provide treatment relief.
The Agency believes that minimize
threat levels will only be used where
they are less stringent than current LDR
levels. The Agency requests comment
on the proposed revisions to part 268
with respect to minimize threat levels.
Table D-l of appendix D to the
preamble presents for comparison
current LDR UTS standards and
proposed minimize threat levels. The
Agency is proposing that for the
constituents listed below/ the risk levels
may substitute for current UTS
treatment levels in 40 CFR 268.48 or for
treatment standards for these
constituents in 40 CFR 268.40. A table
of the proposed minimize threat levels
can be found at proposed 40 CFR 268.60
subpart F in the regulatory text
following this preamble.
2. Constituents for Which Exit Levels
Are Not Minimize Threat Levels
As an alternative to the approach
described in C.I above, die Agency
solicits comment on the background
data underlying the risk evaluations for
these constituents. The Agency believes,
in general, that the constituents
evaluated in the risk analysis have
relatively cpmplete assessments of risk.
The Agency recognizes, however, that
data quality and completeness can vary
among constituents, even for those for
which risk can be assessed. The Agency
solicits comment on both general
criteria for assessing completeness of
data, and also specific constituents for
which use as minimize threat levels to
cap LDR requirements may be
inappropriate.
D. Meeting LDR Requirements
I. Wastes Below Exit Levels as
Generated
EPA proposes tiiat, if a generator
samples a listed waste stream at its
point of generation and analysis of the
sample shows all constituents to be
below exit levels, LDR requirements
would not apply to the waste. EPA is
proposing this result both for
constituents with exit levels based on
multipathway analysis (where, since
exit levels can serve as LDR "minimize
threat" levels that cap current treatment
requirements, the LDR program will
never require treatment to levels lower
than exit levels) and constituents With
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exit levels based on extrapolation from
the multipath analysis or quantitation
levels (where, since EPA has not
proposed to make exit levels into LDR
minimize threat levels.the LDR
programs may require treatment to
levels lower than exit levels).
To claim this relief generators would
have to certify that they sampled their
wastes at the point of generation. In the
interim between sampling and receipt of
analytical results, the generator would
be required to manage the waste as
hazardous. However, EPA would take
the position that this brief period of
Subtitle C regulation would not .subject
the waste to LDR requirements.
EPA believes that position is
consistent with its prior interpretations
of LDR provisions and the D.C. Circuit's
opinion in Chemical Waste
Management//. At issue in that case
was EPA's determination that LDR
treatment standards apply to wastes that
are characteristically hazardous at the
point of generation but that
subsequently cease to exhibit
characteristics and become
nonhazardous wastes. EPA took that
position to ensure that characteristic
wastes receive effective treatment.
Without this requirement, for example,
it would be possible to dilute
characteristic wastes and evade LDR
treatment requirements. The Court held
that EPA must apply this interpretation
consistently to characteristic wastes.
It is not necessary, however, to follow
this interpretation for wastes that are
generated with all constituent
concentrations below exit levels. EPA
can reasonably distinguish between
wastes that are below exit levels at the
point of generation and wastes which
achieved such levels at some
subsequent time. Only wastes which
exceed exit levels at the point of
generation need continued LDR
applicability to ensure that they reduce
constituent concentration or constituent
mobility by complying with LDR
standards rather than using dilution or
some other inferior form of treatment. A
generator of wastes that meet exit levels
as generated would not use waste
treatment to evade LDR requirements.
Rather, he or she might use waste
minimization techniques to reduce
concentration or mobility of
constituents in the precursor to his
waste.
EPA notes that it is proposing to
require listed wastes which exceed exit
levels at the point of generation to meet
LDR treatment requirements, even if the
waste later meets exit levels. EPA
believes that this requirement carries
out the LDR requirements set out in the
Third Third rule and the Chemical
Waste decision.
Finally, EPA notes that it would be
possible to articulate alternative
rationales for exempting from LDR
requirements wastes which meet today's
exit levels as generated. For exit levels
based on extrapolations from the
multipathway analysis, EPA could argue
that extrapolated levels are LDR
"minimize threat" levels. EPA,
however, thinks protection of the
environment is better served by
refraining from such a step and
requiring wastes which exceed such
levels at the point of generation to meet
current technology-based LDR
standards. (As explained above, EPA is
not entirely certain that these
extrapolated levels actually minimize
risks for all constituents.) For exit levels
based on quantitation limits, imposing
LDR requirements would not have any
practical impact. LDR treatment
standards are limited by the same
quantitation limits proposed for this
rule. Consequently, treatment standards
for constituents limited by analytical
capabilities are not lower than die exit
levels.
2. Wastes Above Exit Levels as
Generated
Listed wastes that are above exit
levels as generated would be required to
be treated to the LDR standards in force
at the time if they are placed on the
land.
VII. Dilution
The 1984 RCRA Amendments
(HSWA) established a vigorous national
policy for minimizing the generation of
hazardous wastes. Section 1003 of
RCRA, as amended in 1984, established
a national waste minimization policy
stating that "wherever feasible, the
generation of hazardous waste is to be
reduced or eliminated as expeditiously
as possible". The policy also cited the
need to reduce the volume and toxicity
of hazardous wastes which is
nevertheless generated. Similarly,
section 3005 (h) prescribed that effective
September 1,1985, all RCRA permittees
who generate waste disposed of, treated,
or stored on-site certify, on an annual
basis, that the facility has waste
minimization programs in place. In
addition, section 3002(b) mandates that
hazardous waste generators include a
certification with their hazardous waste
manifests that the generator has a waste
minimization program in place and that
the proposed method of off-site
management minimizes threats to
human health and the environment. In
concert with these HSWA mandates, it
is the Agency's policy to encourage
source reduction (i.e., waste
minimization) and waste treatment as
preferable to disposal and dilution.
EPA has recognized that successful
implementation of the land disposal
restrictions requires that, in general,
dilution be prohibited as a partial or
complete substitute for adequate
treatment of restricted wastes. The
legislative history indicates that such a
prohibition "is particularly important
where regulations are based on
concentrations of hazardous
constituents" (H.R. Rep. no. 198, Part I,
98th Congress, 1st Session 38 (1983)).
The Agency also opposes the dilution
of hazardous wastes for several
technical reasons. Most importantly,
dilution is an environmentally
inappropriate means to reduce toxicant
concentrations because it does not
reduce toxicant loadings to the
environment. The same mass of toxicant
is released to the environment when a'
diluted waste is disposed as would be
if that same waste, prior to dilution,
were to be disposed. While mass
loading of the environment is itself a
serious concern, the potential for
environmental damage is magnified
when toxicants (for example, pesticides
and metals) bioaccumulate in the food
chain. In addition, diluted wastes can
create an unnecessary demand for
scarce solid waste disposal capacity.
For these reasons, dilution is
generally prohibited as a means to
achieve the exemption levels under
today's proposal. Because today's rule
proposes to amend the some of the
current LDR levels by establishing
minimize threat levels, allowing
dilution as a means of achieving
exemptions would be inconsistent with
the ban oh dilution included in the land
disposal restrictions rule (40 CFR
268.3). In addition, dilution would be
inconsistent with the Congressional
purpose of encouraging waste
minimization. Thus, today's proposed
rule specifically prohibits dilution as a
means of attaining the exemption levels
except as provided under the LDR
program under 40 CFR 268.3(b).
VIII. Implementation
Today's proposed rulemaking would
establish a generic set of constituent-
specific exemption levels for listed
hazardous wastes. Wastes with
hazardous constituent concentrations
below the generic exemption levels
would be conditionally exempt from
Subtitle C.s Today's proposed
5 Exempted wastes would continue to be solid
wastes, and as such would require proper
management under subtitle D and other applicable
state laws.
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rulemaking would be self-
implementing; that is, no prior
governmental approval or review of
documentation would be required
before wastes are eligible to exit.
Claimants of an exemption, however,
would be required to meet certain
prerequisites in addition to the generic
constituent concentration levels before
the wastes would be considered non-
hazardous. These testing and
notification requirements are necessary
to ensure that only those hazardous
wastes which truly meet the exemption
criteria exit the subtitle C system. In
addition, certain testing and record-
keeping conditions would be imposed
to maintain the exemption to ensure
that the waste continued to be eligible
for the exemption. Failure to satisfy the
conditions would void the exemption.
A. Implementation Requirements
To make an effective claim, persons
would need to comply with the
following requirements:
—The waste must be sampled and
tested in accordance with a
comprehensive sampling and analysis
plan prepared prior to conducting
sampling and analysis (EPA
recommends, as guidance, using the
basic elements of sampling and
analysis plans described in Chapters
One and Nine of SW-846);
—Representative samples collected in
support of an exemption proposed in
today's notice must consist of a
sufficient number of samples to
represent the spatial and temporal
variability of the waste characteristics;
—The waste must be tested for all
hazardous constituents except those
that should not be present in the
waste as defined by this rule, with
documentation supporting
determination not to test any
constituent available on-site at the
time of the notification;
—If the claimant must test for any
hazardous constituents on table B of
appendix X of 40 CFR part 261, the
waste must also meet treatment
standards for those constituents listed
on UTS table of 40 CFR 268.48;
—A notification must be submitted to
the Regional Administrator (or
authorized State) (hereafter referred to
as the implementation authority),
along with
—A certification signed by the
claimant's authorized representative
attesting to the completeness and
accuracy of the notification, and
—Verification that a notice of the
exemption claim has been placed in a
major local newspaper of general
circulation.
Any deficiencies in compliance with
these requirements would prevent the
exemption from being valid; that is, the
waste would not exit the subtitle C
system. Claimants would not be able to
use their knowledge of the waste alone
to make a determination. Furthermore,
in order to defend a claim that a waste
was exempt under today's proposed rule
and thus exempt from hazardous waste
regulation, claimants would bear the
burden in an enforcement action of
establishing that the waste in question
met the exit levels and the other
requirements for the exemption.
1. Testing Requirements
In today's notice, the Agency is
proposing concentration-based
exemption criteria below which a listed
hazardous waste would be conditionally
exempt from subtitle C compliance. To
best ensure accurate characterizations of
constituent concentrations in these
wastes, the Agency is also proposing
sampling and analysis requirements for
the exemption determination proposed
today. Adherence to these requirements,
however, does not ensure that the
characterization is accurate and
representative of a waste on a continual
basis. It is the generator's responsibility
to ensure that a waste always meets the
exemption requirements proposed today
for all appendix X of 40 .CFR part 261
constituents, regardless of which
constituents the facility is required to
test and how often testing is performed.
To be eligible for an exemption, EPA
is proposing that facilities must (1)
demonstrate that each constituent of
concern is not present above the
specified exemption level in the waste,
(2) demonstrate that the analysis could
have detected the presence of the
constituent at or below the specified
exemption level, and, (3) where
specified, comply with the LDR
standards applicable to the waste.
Today's proposed rule allows that any
reliable analytical method may be used
to demonstrate that no constituent of
concern is present at concentrations
above the exemption levels. It is the
responsibility of the generator to ensure
that the sampling and analysis is
unbiased, precise, and representative of
the waste.
The Agency will consider that the
exemption level was achieved in the
waste matrix if an analysis in which the
constituent' is spiked at the exemption
level indicates that the analyte is
present at that level within analytical
method performance limits (e.g., bias
and precision). The Agency prefers this
empirical demonstration of method
performance through the successful
analysis at the exemption level. The
Agency requests comment on this and
any other approaches to demonstrate
method performance.
In general, the Agency is proposing
testing requirements that would consist
of an initial test to characterize the
waste as exempt, followed by,
subsequent testing to ensure ongoing
compliance with constituents of
concern. A generator of a listed waste on
a one-time basis will only be required to
comply with initial testing
requirements. Wastes produced on an
infrequent (batch) or continuous basis
will have to comply with initial testing
requirements and subsequent testing
requirements as appropriate based on
the volume of the waste. The Agency
asks for comment on this general
approach to testing requirements.
a. Data Evaluation
i. Compliance With the Exit Levels
The Agency is requesting comment on
three approaches of data evaluation.
First, the Agency is proposing that, for
exemptions under today's proposed
rule, generators would be required to
evaluate their waste based on the
maximum detected concentrations of
the exemption constituents. If any
constituent concentration is greater than
its specified exit level, then the waste
would be ineligible for exemption under
today's proposed rule. One advantage of
this approach is that facilities can use
process and waste knowledge to
determine the appropriate number of
representative samples without relying
on a complex, potentially costly
statistical approach to determine an
appropriate number of samples.
However, generators will need to be
sufficiently knowledgeable about their
waste and process to make an unbiased
determination regarding the appropriate
number of samples. Actual sample
representativeness might be difficult to
verify or otherwise assess (on a
statistical basis). Finally, the level of
uncertainty associated with the results
cannot be defined. Because of this,
under this approach, a single composite
sample that validly exceeds the HWIR
exit levels would indicate that the waste
is hazardous and must be handled in
Subtitle C.
Second, the Agency requests
comment on also allowing a second data
evaluation method whereby the
analytical results are evaluated in terms
of an upper confidence limit around an
average concentration. An example of
one method for determining an upper
confidence limit is presented in the
statistical approach found in Chapter
Nine of SW-846 (Third Edition, as
amended by Updates I, II, IIA, and IIB),
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whore, for the purpose of evaluating
solid wastes, the probability level
(confidence interval) of 80 percent is
used. Sample measurements for which
tho upper limit of the 80 percent
confidence interval about the sample
moan is below the regulatory level for
the chemical contaminant are not
considered to be present at levels of
regulatory concern. One main advantage
of this approach is that the number of
samples is statistically determined and
thus it eliminates any bias that might
otherwise be introduced when using
knowledge to determine the appropriate
number of samples. In addition, the
levol of uncertainty associated with the
results can be determined. However, the
main disadvantage of this approach is
that it could be more costly for some
facilities than the proposed approach.
For example, it might require multiple
rounds of sampling to determine the
mean and variance. Highly variable
wastes may require the collection of
many more additional samples than
might otherwise be determined to be
necessary using the first approach.
However, this statistical approach
allows occasional samples to be above
exemption level, as long as the upper
confidence limit of the data overall is
bolow the exit level.
The Agency also requests comment on
a third data evaluation method that
would allow facilities to use long-term
average data to demonstrate compliance
without consideration of the upper
confidence limit. A rolling average of
samples would be taken over the course
of a year on a schedule determined by
tho initial sampling and analysis plan.
As long as the average of the samples
was below the HWIR exit level, the
waste stream would be considered non-
hazardous. This approach would have
the advantage of being simpler than the
second option, while allowing
occasional exceedences of the exit levels
by single samples, as long as the average
concentration is below exit levels.
EPA has modelled risk with the
assumption that the constituents of
concern are uniformly distributed
within the waste at the exit
concentrations. In discussion with the
Hazardous Waste Identification
Dialogue Group, some representatives
noted that actual levels might need to
average significantly below the exit
levels if the exit criteria are to be
consistently met. The second and third
data evaluation methods discussed
abovo help address this issue.
However, EPA and the States have
noted that the only practical approach
for enforcement purposes is to
independently collect samples for
analysis (which may represent a
composite of materials spatially or over
a short time span) and to set up the
regulation so that an exceedence by any
single composite sample during an
inspection could constitute a violation.
It would then be the responsibility of
the generator to refute this, using
historic sampling data and possibly
additional samples to show that the
sample exceedence does not constitute
an overall violation of the HWIR levels.
EPA believes it is important to retain
the practical approach whereby a single
composite sample of a waste at some
arbitrary point in time or space during
a short visit is considered sufficient for
enforcement purposes. However,
because the exit numbers were modeled
based on long-term average
concentrations, the Agency requests
comment on allowing occasional
exceedences as long as the average
concentration meets the exit level.
In addition to the concern about
enforceability, however, EPA has
identified two additional concerns
about using average concentration to
determine compliance. First, not all
waste streams would be disposed of in
the same place. Thus the wastes may on
average be in compliance when they are
generated, but the wastes arriving at the
disposal site (possibly from multiple
sources) may not be, on average, below
the exit levels. Second, EPA has not
modeled the constituents for acute risk.
While the average concentration of
constituents may.be below the exit
levels, the occasional "high"
concentration may be of concern due to
acute health or ecological effects.
One possible way to address some of
these concerns is, in addition to
requiring that the average meet the exit
levels (as in the second and third data
evaluation methods), EPA could require
that all samples be below some "peak"
concentration.
Under this approach, if the average
concentrations are below the exit levels,
and all individual samples are below
the higher peak level, then the generator
would be in compliance and need take
no further action to support the
exemption. EPA or a State would then
be able to confirm waste status without
total reliance on the generator's data and
without the expense of periodic
sampling by EPA or the State. EPA
requests comment on this issue,
including any information on setting
peak levels.
For any of the three data evaluation
approaches, representative samples
must be collected in support of
exemption under today's proposed rule,
consisting of a sufficient number of
samples to represent the spatial and
temporal variability of the waste
characteristics, regardless of how the
sample number is determined.
For the identification and handling of
"outliers", the Agency is recommending
that testing for outliers should be done
if an observation seems particularly
high or low compared to the rest of the
data set. If an outlier is identified, the
result should not be treated as such
until a specific reason for the abnormal
measurement can be determined (e.g.
contaminated sampling equipment,
laboratory contamination, data
transcription error). If a specific reason
is documented, the result should be
excluded from further data evaluation. If
a plausible reason cannot be found, the
observations should be treated as a true,
albeit extreme, value and not excluded
from the data evaluation, as waste
composition can vary. The Agency
solicits comments on implementable
techniques for the identification of
analytical outliers.
The results of the tests of all of the
constituents on the exemption list
would be required to show the
constituent concentration to be at or
below the exit level in order for the
claimant to be eligible for an exemption.
In the case where a constituent's exit
level is based on the quantitation
criteria (EQC, as described in section
IV.E.), in addition to showing a non-
detect at the exit level, the waste would
be required to meet applicable
requirements set forth at 40 CFR part
268. Certain facilities may have
difficulty quantifying a constituent at
the exit level due to matrix interference
effects, but the Agency expects
exempted wastes to have relatively
clean matrices such that exit levels
should be able to be achieved. The
Agency believes that the exit level must
be met in order for a waste to exit
Subtitle C; therefore, waste streams that
cannot meet exit levels would not exit
under today's rule. The Agency asks for
comment on this approach.
ii. Wastewater and Nonwastewater
Categories
Throughout today's proposal and
background documentation, all of the
exit levels have been described as being
applicable to two categories of wastes
using the terms wastewater and non-
wastewater6. EPA used these terms as
afi initial means of distinguishing two
waste categories that are inherent to
how the exit levels were developed, by
taking into account how these wastes
6The terms "wastewater" and "non-wastewater"
are used genetically in today's preamble and rule,
and do not represent the land disposal restriction
definitions in 40 CFR 268.2(d) and CO, although one
option EPA is requesting comment on in this
section is the use of those definitions.
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66388 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
will be managed (i.e., stored, treated,
and disposed), and also how the wastes
would be expected to behave in the
environment. In the development of the
exit levels, several waste management
units were evaluated in the underlying
risk analysis. The units chosen for
• evaluation were those that are
considered most likely to manage the
types of wastes that would be expected
to exit Subtitle C regulation under
today's exemption. Although these units
will likely receive to some degree both
forms of waste, in general there are
technical, physical, and sometimes legal
constraints on what types of waste are
managed in each. The Agency
considered ash monofills, waste piles,
and land application units as typically
managing waste materials that can be
considered "solid" or "non-
wastewater," while tanks and surface
impoundments typically manage
"liquid" or "wastewater." Based on
these assumptions, results from the
analysis of risk from these specific
waste management units were then used
to generate the corresponding exit levels
for non-wastewater and wastewater.
In considering how to develop final
definitions and terms for these two
waste categories, the Agency's goal is to
establish definitions that are clear,
concise, and easily distinguishable from
other similar terms such that a generator
can readily determine which set of exit
levels to apply to the waste being
, evaluated for the exemption. EPA
requests comment on three options for
defining these two waste categories to
determine which set of exit levels to
apply to a listed waste eligible for
today's proposed exemption. EPA
emphasizes that these definitions will
only apply in the context of today's exit
rule.
The Agency also requests comment on
whether it is reasonable in all three
options to allow a generator the
alternative options of separating in the
laboratory the solid (or nonwastewater)
portion of the waste from the liquid (or
wastewater) portion of the waste,
analyzing the resultant portions,
comparing the results to the
corresponding exit levels, and treating
the waste as exempt if all exit levels are
met in both portions.
Option 1: Using Percent Solids—EPA
prefers the option of defining the two
categories of exit levels as "solid" and
"liquid" exit levels, where the
distinction between solids and liquids is
based upon the percent solids content of
the waste, as determined using Section
7.1 of the Toxicity Characteristic Leach
Procedure (TCLP) in SW-846.
Specifically, the option would define
wastes containing 15 percent solids by
weight or greater as solids,7, while
wastes with less than 15 percent solids
by weight be defined as liquids. EPA
believes that the 15 percent cutoff is a
reasonable distinction between the two
categories of exit levels, for the
following reasons. Because there are
general prohibitions on liquids or
wastes containing free liquids in non-
hazardous waste landfills accepting
municipal wastes, the Agency does not
envision wastes containing less than 15
percent solids being managed in these
units. Similarly, it is unlikely that waste
containing less than 15 percent solids
will be stored in waste piles due to
obvious physical limitations. For land
application units, EPA believes that 15
percent solids content by weight is a
reasonable lower limit for the types of
wastes typically managed in these units;
indeed, this was the value used in the
land application unit scenario in the
groundwater modeling portion of the
risk assessment underlying today's exit
levels.
Because of these limitations, EPA
believes that wastes containing less than
15 percent solids will more frequently
be managed in the types of units
associated with wastewater treatment,
such as tanks and surface
impoundments. In fact, EPA believes
that many wastes falling into the liquid
category under this definition, that can
realistically exit under today's proposed
exit rule, will likely be wastewaters that.
have undergone treatment and that
contain much less than 15 percent
solids. EPA presumes that in many
cases the separation ofwater from solids
will be occurring as part of routine
wastewater treatment, and generators
will be either be evaluating the solid
residues (which would clearly meet our
solid definition), or the treated water,
much of which is currently discharged
under the Clean Water Act and therefore
likely has limits on the amount of solids
present.
EPA also requests comment on
alternative ways of determining percent
solids content, including generator
knowledge of the waste or results of
previous analyses. The Agency believes
that in many cases, particularly for
fairly dry or fairly wet wastes, the
generator can immediately ascertain
from a visual inspection that the percent
solids content is well above or well
below the 15 percent solids value.
7 EPA will avoid use of the term "solid waste"
when describing the category of exit levels that are
defined, as solids under this option in today's
proposal. This is to avoid confusion with the
existing term "solid waste" in the RCRA program,
which has specific statutory and regulatory
definitions, which have no relationship to whether
a waste is a physically a solid or a liquid.
Option 2: Using LDR Definitions—
EPA also requests comment on the use
of the same terms and definitions
currently used under the land disposal
restrictions. Wastewater is defined as
waste containing less than 1 percent
total suspended solids (TSS) and less
than 1 percent total organic carbon, or
TOG (40 CFR 268.2(f)). Non-wastewater
is defined as any waste that is not a
wastewater (40 CFR 268.2(d)). The
principle advantage of this approach is
it allows the use of consistent
definitions for wastewater and
nonwastewater in both today's exit
system for listed wastes, and the LDR
program. The advantage of this :
consistency is particularly apparent for
those cases where LDR treatment
standards are conditions of exit under
today's rule. One disadvantage of this
approach is that it defines wastes
containing greater than 1 percent TSS as
non-wastewater, even though these
wastes will likely be managed in
wastewater treatment systems using
tanks and surface impoundments,
which is inconsistent with the way in •
which the results from the risk analysis
were used in developing exit levels. The
Agency requests comment on this
approach as an alternative to Option 1.
Option 3: Using the Paint Filter
Liquids Test—The third option is to use
the terms "liquid" and "solid" as in
Option 1, but to use EPA Method 9095
from SW-846, the Paint Filter Liquids
Test, to determine whether the waste
being evaluated for exit is a liquid or a
sojid. Under this option, any waste
determined to contain free liquids using
Method 9095 would be considered a
liquid, and the exit numbers currently
in the wastewater category would apply
to that waste. Conversely, a waste would
be defined as a solid, and the
nonwastewater exit levels would apply,
if the waste does not contain free liquids
using Method 9095. Under this option,
EPA realizes that many wastes
appearing like solid materials would
actually be defined as liquids.
Method 9095 is presently used in
defining the term "liquid waste" in the
solid waste disposal facility criteria, for
determining compliance with the
prohibition on disposing of bulk or
containerized liquid in municipal solid
waste landfills (see 40 CFR 258.28).
Method 9095 is also used in
determining compliance with the
prohibition on bulk or containerized
liquids in hazardous waste landfills
(264.314(c)).
iii. Totals and TCLP Analyses
Today's rule proposes that the
claimant would be required to test the
waste for which today's exemption is
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Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66389
being claimed to prove that constituent
concentrations in the waste do not
exceed the exit level(s) for each
constituent that should be present in the
waste.
The claimant would determine which
category of exit levels would apply (e.g.,
wastewater or nonwastewater) to his
waste. In a previous section of today's
rule, the Agency requests comment on
several options to define these two
categories. For a wastewater waste to be
eligible for exit, every constituent in the
waste must comply with the wastewater
total constituent exit concentration. For
a nonwastewater waste to be eligible for
exit, every constituent in the waste must
comply with the nonwastewater total
constituent exit level as well as the
nonwastewater leach exit level.
A test for total concentration would
be required for each constituent in the
waste regardless of whether the waste is
a wastowater or a nonwastewater to
determine that the total constituent exit
concentration has not been exceeded.
For non-wastewaters, a claimant must
also prove that the measurable leachate
concentrations do not exceed the
nonwastewater leach exit levels. The
Agency proposes to allow claimants to
either use a calculational screen or to
use the Toxicity Characteristic Leaching
Procedure (TCLP, Test Method 1311 in
"Test Methods for Evaluating Solid
Waste, Physical/Chemical Methods,"
EPA Publication SW-846) to make a
determination that constituent
concentrations do not exceed
nonwastewater leach exit levels.
Discussion concerning the methodology
of a calculational screen is described
bolow.
Section 1.2 of the TCLP allows for a
compositional (total) analysis in lieu of
the TCLP when the constituent of
concern is absent from the waste, or if
present, is at such a low concentration
that the appropriate regulatory level
could not be exceeded.
For wastes that are 100% solid as
defined by the TCLP, the maximum
theoretical leachate concentration can
be calculated by dividing the total
concentration of the constituent by 20.
The dilution factor of 20 reflects the
liquid to solid ratio employed in the
extraction procedure. This value then
can be compared to the appropriate
regulatory concentration. If this value is
below the regulatory concentration, the
TCLP need not be performed. If the
value is above the regulatory
concentration, the waste may then be
subjected to the TCLP to determine its
regulatory status.
The same principal applies to wastes
that are less than 100% solid. In this
case, however, both the liquid and solid
portion of the waste are analyzed for
total constituency and the results are
combined to determine the maximum
leachable concentration of the waste.
The following may be used to calculate
the maximum theoretical concentration
in the leachate.
[AxB]+[CxD]
B +
20—xD
. kg
= E
where:
A = Concentration of the analyte in
liquid portion of the sample (mg/L)
B = Volume of the liquid portion of the
sample (L)
C = Concentration of the analyte in the
solid portion of the sample (mg/kg)
D = Weight of the solid portion of the
sample (kg)
E = Maximum theoretical concentration
in leachate (mg/L)
If:
E
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66390 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
wastes. Method 1311 underestimates the
mobility of constituents from many oily
wastes due to filter clogging problems,
can be imprecise for oily wastes, and
has several operational problems.
Conversely, Method 1330 is believed to
overestimate mobility of constituents
from oily wastes since it emulates a
worst case scenario by using solvents to
extract contaminants from the oil. None
of the available laboratory procedures is
fully satisfactory. Rather, they bracket
the range of possible leaching for oily
wastes.
In addition, EPA does not have a good
definition for what constitutes an oily
waste. EPA originally defined oily
wastes as those materials that clogged
the filter during Method 1311 (TCLP)
extraction. EPA requests comment on
how to better define what an oily waste
is.
EPA also requests comment on which
of the two tests methods (1311 or 1330)
should be used and why should one test
be chosen over the other for predicting
the concentrations of contaminants in
leachate from wastes being managed in
landfills. EPA also requests comment on
whether there are any alternative test
methods or models that could be used
for predicting the mobility of oily
materials. Such procedures need to be
both scientifically credible and
environmentally protective. Methods
need to identify material that might be
released from the waste and enter the
soil. Release is defined as movement of
either the liquid phase of the waste or
leached contaminants through the
bottom of the waste unit to the
subsurface soil immediately underlying
the disposal point. Once contaminants
pass this point their ultimate fate in
terms of impact on down-gradient water
supplies can be estimated by the
ground-water fate and transport model
(EPACMOW model).
EPA also requests comment on any
additional problems with oily waste
leachability not covered here, and
whether the volatilization or other
attributes of constituents should be
considered in the development of a test.
Oily wastes also pose modeling
challenges in groundwater because they
do not disperse in the same pattern as
aqueous liquids. This affects the
movement of the constituents in the
material. In the event of a release of
waste at or near the soil surface, the
waste will migrate downward until it
reaches the water table. Light non-
aqueous phase liquids (LNAPLs) will
then tend to migrate laterally, forming a
pancake on top of the water table. Dense
non-aqueous phase liquids (DNAPLs) on
the other hand will sink to the base of
an aquifer and not show much lateral
spreading until an impermeable layer is
reached. EPA is requesting comment on
what sort of wastes or what constituents
exhibit these behaviors and how to
define that set of wastes. Constituents
that have been associated with DNAPLs
include dichlorobenzenes, PCBs,
napthalenes, chloroform, carbon
tetrachloride pentachlorophenol,
cresols, and several PAHs. However,
trace amounts of these constituents are
unlikely to pose a DNAPL problem. A
DNAPL problem is likely to occur when
there is sufficient concentration to flow
as undissolved liquid that would then
form the sort of complex reservoirs that
subsequently slowly dissolve into
groundwater. The Agency requests
comment on concentrations of these or
similar chemicals that are likely to pose
DNAPL problems and whether the
proposed exit levels in totals or, for
nonwastewaters in leach levels, are
sufficient to limit wastes exiting for
which a DNAPL or LNAPL problem
would need to be explicitly evaluated.
The Agency is continuing to work on
developing tests and models for
determining the leaching potential of
oily materials and may propose them in
future rulemaking. In the meantime,
EPA is today proposing to apply the
levels as proposed in this rule to oily
wastes, but seeks comment on whether
instead.there is a definable class of
wastes for which these levels cannot
reasonably be concluded to be
protective.
b. Initial Test
The Agency is proposing in today's .
rule that there would be an initial test
before a facility would be eligible for an
exemption. The initial test would be the
primary tool to characterize the waste as
exempt. Results from this initial test
would be sent to the implementing
agency. The public could request the
implementing agency to make the
results available.
EPA is proposing to require initial
testing of all of the 386 constituents on
appendix X of 40 CFR part 261 except
those that the claimant determines
should not be present in the waste. EPA
would require the claimant to document
the basis of each determination that a
constituent should not be present. The
claimant must submit the
documentation to the implementing
agency and retain a copy on site for
three years. No claimant may determine
that any of the following categories of
constituents should not be present:
—Constituents set out in appendix VII
to part 261 as the basis for listing the
wastestream for which exemption is
sought;
—Constituents listed in the table to 40
CFR 268.40 as regulated hazardous
constituents for LDR treatment of the
waste stream;
—Constituents detected in any previous
analysis of the same wastestream
conducted by or on behalf of the
claimant;
— Constituents introduced into the
process which generates the
wastestream; and
—Constituents which the claimant
knows or has reason to believe are
byproducts or side reactions to the
process that generates the
wastestream.
The Agency requests comment on
whether these are the appropriate
criteria to be used to determine what
should not be present in the waste. The
Agency also requests comment on
requiring claimants who are not waste
generators to consult the generator prior
to determining that a constituent is not
introduced into the process or that a
constituent is not a byproduct or side
product of the process. EPA believes
that it is unlikely that a non-generator
claimant would have sufficient
knowledge of the production process to
make adequate determinations on these
issues. EPA requests comment on the
type of documentation that it should
require. The generator could co-sign the
document that sets out the reasons for
determining that the claimant need not
test for a constituent, or the generator
could prepare a separate supporting
document that would be attached to the
document for submission to the
implementing agency and retention in
. the claimant's files.
The Agency is soliciting comment on
whether the absence of constituents in
the following documents could
constitute sufficient justification for not
analyzing all of the constituents listed
in 40 CFR part 261 appendix X.
—40 CFR part 261 appendix VII
highlighted to show which
constituents are listed for each waste
code applicable to that waste;
—40 CFR 268.40 highlighted to show
which constituents are regulated
under the land disposal restrictions
for each waste code applicable to that
waste;
—EPCRA Toxic Release Inventory
reports highlighted to show which
constituents are reported as being
"used" in the manufacturing process
from which that waste is generated
(based on the EPCRA definition of
"use");
—NPDES discharge permits highlighted
to show which constituents are
required to be monitored in
wastewaters with which that waste is
commingled or will be commingled;
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Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66391
—State or Local emissions monitoring
permits or documents (e.g., stack
emissions, fugitive emissions,
groundwater monitoring, wastewater
discharges, etc.,) highlighted to
indicate \vhich constituents are
required to be monitored as potential
emissions from units in which that
waste is managed or will be managed;
—Responses to government and/or trade
group data collection efforts (e.g.,
biennial reports, TSD surveys) that
require submission of waste-specific
constituent information;
—Published literature (e.g., journals,
presentations, chemical and
engineering reference documents,
health and safety handbooks, material
safety data sheets, etc.,) highlighted to
indicate constituents that are formed
or potentially formed from side
reactions, degradation, or reactivity of
the products, reactants, or solvents
used in the manufacturing process
generating that waste;
—Plant-specific process flow diagrams
or process descriptions highlighted to
indicate constituents that are formed
or potentially formed from side
reactions, degradation, or reactivity of
the products, reactants, or solvents
used in the manufacturing process
generating that waste;
—Product specifications or constituent-
specific labeling requirements under
federal regulations, state regulations,
or non-governmental standards (i.e,
per product-grade) that identify
constituents that are expected to be
present in the products from which
the waste was generated, highlighted
to indicate those constituents
identified as part of these
specifications or standards (excluding
chemical additives or preservatives
that are placed in the products
subsequent to the generation of the
waste for which exit is claimed);
—Waste profile data sheets, such as
those submitted to commercial \vaste
handlers, highlighted to show the
constituents that were found or
expected to be present in that waste;
and/or
—A certified, third party engineering
, analysis of the process generating that
waste that provides qualitative
verification of the theories behind the
anticipated absence of certain
chemical classes or groups of
Appendix X of 40 CFR 261
constituents such as pesticides,
pharmaceutical, halogenated solvents,
carbamate, organo-sulfur compounds,
known gases, cyanides, etc.;
—Any other available quantitative or
qualitative constituent information
specific to that waste
Relevant information includes not
only those document sections that
indicate which constituents are present,
but also cover pages that indicate the
source of the document segments and
signature pages to verify authenticity of
government-approved documents
(where appropriate). For the verification
purposes, page numbers should also be
clearly identified for each document.
EPA is also soliciting information on
additional readily available
documentation that could be added to
this list that would not impose an
unreasonable records burden on both
the generator and enforcement officials
(for example, the Agency believes that
requiring highlighted copies of copious
amounts of monitoring data would be
redundant and would significantly
impede enforcement review). EPA
believes that requiring copies of only
relevant portions of these documents,
highlighted to indicate the chemicals
present, should minimize the burden
associated with this documentation
requirement significantly.
Regardless of which constituents a
facility tests, the facility is responsible
for ensuring that each constituent in the
waste meets its applicable exit level.
The Agency believes that the tailored
initial test described above will ensure
accurate waste characterizations of the
waste streams while focusing testing
requirements to those constituents that
are of concern. A facility could
determine whether a constituent would
be present. A facility would not be
authorized to determine that the
constituents in the waste meet the
exemption levels based on knowledge of
the waste or material. This approach
both reduces unnecessary testing costs
and allows for more frequent monitoring
of those constituents that are of concern.
The Agency is soliciting comment on
whether this proposed approach to an
initial test is appropriate.
The Agency asks for comment on
taking the opposite approach: requiring
each claimant to test only for those
constituents that the claimant
determines "could be present" for that
waste. This would be a systematic way
for facilities to focus the list of
hazardous constituents to those that are
mostly to be present in the waste. EPA
requests comment on requiring at a
minimum testing of the following
categories of constituents:
—Constituents set out in appendix VII
to part 261 as the basis for listing the
wastestream for which exemption is
sought;
—Constituents listed in the table to 40
CFR 268.40 as regulated hazardous
constituents for LDR treatment of the
waste stream ;
—Constituents detected in any previous
analysis of the same wastestream
conducted by or on behalf of the
claimant;
—Constituents introduced into the
process which generates the
wastestream; and
—Constituents which the claimant
knows or has reason to believe are
byproducts or side reactions to the
process that generates the
wastestream.
The Agency asks for comment on the
completeness of the proposed
mandatory testing criteria. In addition,
the Agency requests comment on
whether testing should be required for
those constituents that do not meet any
of the criteria of "could be present." The
Agency also requests comment on
whether documentation should be
required to demonstrate that those
constituents that were not tested did not
meet any of the "could be present"
criteria.
EPA requests comment on another
approach to determining which
constituents need to be analyzed by a
claimant. The approach would be that
the claimant needs to provide data on
all additional constituents listed in
appendix X of 40 CFR part 261 of
today's rulemaking for which a method
used by the generator to detect other
constituents which the claimant is
required to test can easily determine
concentrations. Thus, for example, if a
waste was listed for a constituent for
which GC/MS is an appropriate method
used by the claimant, the claimant
would also be required to ask the
laboratory to provide information on all
other constituents listed in appendix X
of 40 CFR part 261 of today's proposed
rulemaking for which the GC/MS is also
an appropriate method.
EPA did not use this in its primary
proposal because the Agency realized
that implementation of this concept
become more complex than it appears.
For example, even when using GC/MS,
there may be sample preparation
techniques, dilutions, and similar issues
that determine which constituents can
be measured in the appropriate
concentration ranges using the method.
However, there is something
intuitively reasonable and attractive in
asking claimant to gather and provide
information that is easily obtainable and
would provide additional confidence
and certainty. EPA solicits comments on
this idea and ways to implement it.
The Agency requests comment on
whether there is some other way to
focus the scope of testing requirements
or if the only way to ensure accurate
waste characterizations would be to
require testing for all 386 constituents.
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66392 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
The FACA suggested EPA should
define, for major waste streams, a set of
constituents that it believes would fairly
characterize those waste streams-. The
Agency believes such an approach may
be desirable. However, the Agency notes
that this could require it to expend
significant resources. The Agency
requests comments on the feasibility or
need for this approach in the long term.
EPA recognizes that some generators
may wish to assert claims for protection
of confidential business information
(CBI) for some to the information that
supports an exit claim. Material that is
classified as CBI may be reviewed by
EPA, but may not be released to the
public. States may have similar
provisions under state law. EPA
requests comments on two options for
addressing CBI information.
First, EPA requests comment on the
option of prohibiting any person from
asserting a claim of exit under this rule
if that person wishes to claim CBI
protection for any data or information
used to support the exit claim,
including all information submitted to
the implementing agency in the
notification package and all information
required to be maintained by the
claimant on site and furnished to the
agency on request. A generator who
wished to rely on CBI data to support
an exemption claim for a listed
hazardous waste would need to file a
delisting petition with EPA or a state
authorized for delisting.
EPA believes such an approach may
be necessary because the exits proposed
today are self-implementing. The public
would not have the assurance of
knowing that EPA or a.state agency had
reviewed the claimant's data and
determined that it showed that the
claimant's waste posed low risks to
human health and the environment.
Members of the public may not feel that
they are adequately protected by the fact
that EPA and authorized states could
obtain the CBI data and use it (with
appropriate precautions against
disclosure) in an enforcement action if
warranted. They may feel that the
number of claims will strain agency
inspection and enforcement resources,
making it important for them to be able
to bring their own citizen enforcement
actions under section 7002 of RCRA.
At the same time EPA is sensitive to
potentially legitimate business needs to
protect information supporting an exit
claim. Some firms may not wish to
release detailed information about the
chemical composition of their process
waste streams. EPA also recognizes that
the federal delisting process is
considerably slower and imposes more
procedural burdens than the self-
implementing exit scheme. EPA
requests comment on the alternative of
creating a limited prior approval process
for exit claims involving CBI claims.
EPA anticipates that rulemaking would
not be required. However, states that
wish to obtain authorization for today's
exit program might not be required to
adopt this feature because they could
argue that failure to provide a review
process for CBI claims would not make
their programs less stringent than the
federal program.
EPA also notes that CBI protection is
not absolute. EPA has authority under
RCRA to release CBI information to the
public as necessary to support
rulemaking proceedings. (In fact, EPA
could try to support the first option
above by arguing that it was exercising
in this proceeding its authority to waive
protection for all of the individual exit
claims that "implement" the rule.) Also,
a citizen that has sufficient evidence of
a violation to file a complaint in court
may be able to persuade the court to
order a limited release of the data for
use in the enforcement proceedings.
2. Notification Requirements
The Agency is proposing that the
required notification to the
implementing authority would include
the following information:
—The name, address, and RCRA ID
number of the person claiming the
exemption;
—The applicable EPA Hazardous Waste
Codes;
—A brief description of the process that
generated the waste;
—An estimate of the average and
maximum monthly and annual
quantities of each waste claimed to be
exempt;
—Documentation for any claim that a
constituent is not present;
—The results of all analyses and
estimates of constituent
concentrations and all quantitation
limits achieved;
—Documentation that any constituents
on Table B to appendix X of 40 CFR
part 261 have met the applicable
treatment standards in § 268.48,
unless the claimant is claiming the
exemption under § 261.36(e);
—Evidence that the public notification
requirements have been satisfied; and
—A certification signed by the person
claiming the exemption or his
authorized representative. .
The Agency is taking comment on
whether the following additional
information should also be sent to the
implementing authority:
—The name and address of the
laboratory which performed the
analysis;
—A copy of the sampling and analysis
plan used for making the exemption
determination;
—A description of any chain-of-custody
procedures;
—Whether the identity of the disposal
facility should be included in the
notification package;
—Dates of sampling and analysis; and
—A description of the (temporal and)
spatial locations of the demonstration
samples.
Also, the Agency is taking comment on
whether, if the disposal facility is
different than the claimant's facility, the
claimant should also include as part of
the notification package documentation
that the claimant informed the disposal
facility of the exempt status of the
waste.
A complete notification package
would include all required information
in the notification and all required
certifications signed by the appropriate
individual, as identified in the
regulations. Failure to submit a
notification package if the exemption is
being claimed or submission of an •
incomplete notification package would
be a violation of RCRA requirements
and thus subject to penalties and
injunctive relief under section 3008(a)
of RCRA and possible criminal liability
under section 3008(d) of RCRA. As a
necessary prerequisite to claiming an
exemption, the burden would be on the
claimant to establish that a complete
notification package was submitted to
the implementing authority to assert in
an enforcement action that the waste is
exempt.
It should be noted that, regardless of
whether the sampling and analysis plan
must be included with the notification
to the implementing agency, a current
sampling and analysis plan must be
developed and used to establish the
waste's eligibility for exemption, and
must be available upon request to the
implementing authority at the time the
notification package is submitted and at
least for three years. The sampling and
analysis plan must demonstrate that the
samples to be taken and analyzed will
be representative of any spatial and
temporal variations in the subject waste.
Furthermore, it should be noted that
submission of sampling and analysis
plans with the notification to the
implementing authority does not change
the self-implementing nature of the
exemption. Submission of such plans
would not be for review or approval of
exemption claims prior to the
exemption.becoming effective. The
implementing agency would be under
no obligation to undertake such review
or approval prior to the exemption
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becoming effective, and failure to
undertake such prior review would not
preclude a subsequent enforcement
action should the exemption claim later
be determined to be inaccurate or
otherwise invalid.
As proposed, the certification
required to accompany the notification
must attest that the waste in question
meets all relevant constituent
concentration exit levels and that the
information in the notification package
is true, accurate, and complete. The
Agency is taking comment on whether
this certification is sufficient assurance
that the claimant has made best efforts
to accurately characterize the waste or if
additional certification language or
additional certifications (e.g., from an
analytical laboratory) are necessary.
The notification package wouldhe
required to be submitted by certified
mail with return receipt requested, or
other commercial carrier that provided
written confirmation of delivery. No
claim would be effective until the
claimant received the return notification
indicating that the package had been
delivered.
Submission of the notification
package to the implementing authority,
however, is not equivalent to approval
or verification of the exemption claim.
Submission of a notification package
would not preclude or in any way limit
tho implementing authority's ability to
take a subsequent enforcement action
should it determine that the initial
requirements of exemption were never
met or that the conditions for
maintaining the exemption are not
satisfied.
The Agency is taking comment on
whether, instead of the exemption
becoming effective upon confirmation of
delivery of the notification package,
there should be some brief waiting
period prior to the exemption becoming
effective.
Such a period (e.g., 30 or 60 days)
could be used by the implementing
authority to review notification
packages for completeness or for indicia
of concerns that would lead to
prioritized enforcement, although the
exemption would still become
automatic after the period regardless of
whether any action was taken by the
implementing authority. As an
alternative, the period could be
designed to provide the implementing
authority an opportunity to determine
that a claimant should not be able to
avail itself of the exemption without
some further review and to notify the
claimant of its views.
Under either approach, governmental
review would be discretionary and the
lack of such review would not be an
indication of governmental approval of
the exemption claim. To ensure that
there would be no confusion on this
point, the certification could include a
statement of recognition that expiration
of the delay period without comment by
the overseeing agency is not the
equivalent of agency approval that the
claim is accurate. The Agency has not
chosen to propose a delayed
implementation approach because it
believes a short time frame, particularly
combined with an automatic effective
date, would not provide an opportunity
for thorough prior review and would, at
best, provide only marginal benefits as
a screening device for potentially
problematic claims. The Agency,
however, requests comment on whether
such a delay would be beneficial to
monitoring claims and if there are
procedural or other concerns relating to
such a delay.
B. Implementation Conditions
After the exit claim has become
effective, the claimant would have to
continue to meet certain conditions to
maintain the exemption. Failure to
satisfy any of the conditions would void
the exemption and subject the waste to
applicable subtitle C requirements.
Under this proposal, wastes must
continue to meet the generic exemption
levels established for exit to remain
non-hazardous. Separate and distinct
from any requirement or condition that
might be established under this
rulemaking, all generators—including
claimants of today's proposed
exemption—would have a continuing
obligation to identify whether they are
generating a hazardous waste and to
notify the appropriate governmental
official if they are generating a
hazardous waste. Section 3010; 40 CFR
261.11. If wastes claimed as exempt
under today's proposed rule test above
exit levels at any time, that waste and
subsequently generated waste would
have to be managed as hazardous
waste—including compliance with all
notification requirements—until testing
demonstrated that the waste was below
exit levels.8
8Compliance'with HWIR exemption levels will
be measured from the last available test data or from
the latest representative samples taken from the
waste in question. Testing which shows constituent
concentration levels above exemption levels will
not affect wastes previously generated under a valid
claim of exemption based upon representative
samples. Similarly, testing, which shows that a
waste which tested above exit levels once again
tested below all relevant exit levels will exempt all
waste generated on or after the date the samples
were taken. Waste which exceeded the exit levels
would not be able to requalify for the exemption.
1. Records Maintained on Site
In addition to the information
described in the Notification Section
above, the Agency is also proposing that
the following information concerning
the initial testing and retesting be
maintained in the files on site at the
facility making the exemption claim for
at least three years:
—All information required to be
submitted to the implementing
authority as part of the notification of
the claim;
—The dates and times waste samples
were obtained, and the dates the
samples were analyzed;
—The names and qualifications of the
person(s) who obtained the samples;
—A description of the (temporal and)
spatial locations of the samples;
—The name and address of the
laboratory facility at which analyses
of the samples were performed;
—A description of the analytical
methods used, including any clean-up
and extraction methods;
—All quantitation limits achieved and
all other quality control results for the
analyses (including method blanks,
duplicate analyses, matrix spikes,
etc.), laboratory quality assurance
data, and a description of any
deviations from published analytical
methods or from the plan which
occurred;
—All laboratory documentation that
support the analytical results, unless
a contract between the claimant and
the laboratory provides for the
documentation to be maintained by
the laboratory for the period specified
in § 261.36(b)(2) and also provides for
the availability of the documentation
to the claimant upon request;
—If the generator claims a waste is
exempt from part 268 requirements
pursuant to § 261.36(e),
documentation to substantiate such a
claim.
The Agency requests comment on the
proposed information maintenance
requirements and comment on
additional information that may be
necessary.
In addition, claimants will be
required to retain certain information
concerning retesting of wastes as
described below and set out in the text
of proposed 40 CFR 261.36(d)(6)(ii).
2. Testing Conditions
Claimants would continue to
periodically test their wastes as a
condition of the exemption.9 Failure to
test and maintain documentation of the
9 Wastes generated on a one-time basis would not
be subject to this requirement.
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66394 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
testing in accordance with the
requirements of proposed 40 CFR
261.36(d) would void the exemption.
The Agency believes that required
subsequent testing is necessary to
maintain accurate waste .
characterizations. Subsequent testing
would be an ongoing exemption
condition and would be the minimum
testing required to maintain an
exemption. A tailored constituent list
setting out minimum requirements for
testing purposes should not be confused
with the facility's ongoing requirement
to maintain constituent concentrations
below exit levels for all constituents on
appendix X of 40 CFR part 261. Results
from subsequent testing would be
required to be maintained on-site.
The scope of subsequent testing
would focus primarily on those
constituents from appendix X of 40 CFR
part 261 that are of concern based on the
initial test. The list of constituents for
which a claimant would be required to
test would, at a minimum, include each
constituent that was detected in the
initial test within an order of magnitude
below the exit level for that constituent,
and any constituent listed in Table B of
appendix X of 40 CFR part 261 that is
also identified as a basis for listing the
waste or appendix VII to part 261 or
listed as a regulated hazardous
constituent for the waste in the table to
40 CFR 268.40. The claimant would also
be required to test for any other
constituent which the claimant had
reason to believe was newly present in
the waste since the most recent previous
test.
The Agency proposes that the
frequency with which a facility would
be required to perform subsequent
testing would be determined based on
the volume of waste which the facility
is declaring exempt. Those facilities
with large-volume waste streams would
perform subsequent testing more often
than those facilities with low- or
medium- volume waste streams. The
claimant would be responsible for
determining the volume of annual
exempt waste. The Agency asks for
ideas and comments on whether
guidance should be made available for
claimants on how to measure annual
volumes. Justification of annual
volumes would be sent to the Director
in the notification package. The Agency
believes that accurate waste
characterizations are important for
waste volumes of all sizes; however,
inaccurately characterized large-volume
wastes have greater potential to harm
the environment than do smaller-
volume wastes. In today's rule, the
Agency is proposing the following
requirements for the first three years of
subsequent testing:
—Wastes generated at the time of
exemption is initially claimed in
volumes greater than 10,000 tons/year
would be tested four times a year for
the first three years of the exemption.
—Wastes generated at the time of
exemption is initially claimed in
volumes greater than 1000 tons/year
but less than 10,000 tons/year would
be tested twice a year for the first
three years of the exemption.
—Wastes generated at the time of
exemption is initially claimed in
volumes less than 1000 tons/year
would be tested once a year for the
first three years of the exemption.
EPA requests comment on whether it
should allow the Agency proposes that
if a waste maintains exempt status for
three years, the frequency of subsequent
testing would then be reduced to once
a year, regardless of the volume
produced. The Agency believes that
three years of subsequent testing should
provide a facility with adequate data to
assess the potential for variability in the
waste. The Agency requests comment
on the frequency of subsequent testing.
The Agency requests comment on an
approach that the FACA suggested. The
approach consisted of a comprehensive
test, similar to an initial test, that is
required every 3 or 5 years of an
exemption because of the strong
reliance on the initial test's results in
determining the scope of subsequent
testing.
The Agency also requests comment on
whether follow-up testing should be
eliminated entirely after the first three
year period. In addition, the Agency
asks if a certification of compliance with
all relevant exit levels could suffice in
lieu of testing at the end of three years.
3. Testing Frequency and Process
Change
Under today's proposal, the claimant
has a continuing obligation to verify that
the waste continues to meet the
exemption criteria, including meeting
the exemption constituent concentration
levels. Process changes that may either
increase the number of hazardous
constituents in the exempted waste or
increase the concentration of hazardous
constituents already present, should put
a claimant on notice that there may be
changes in the waste that may affect its
continued eligibility for exemption. The
Agency, however, is not proposing to
require new sampling and analysis
whenever there is a process change that
may affect the exempt status of the
waste.
The Agency is taking comment on
whether it is necessary to require as a
condition of maintaining the exemption
that wastes be re-tested after a process
change and, if so, what the scope of
such re-testing should be. The Agency
would like to know if the testing
frequency proposed or more frequent
testing would provide a clearer
indicator of waste changes of concern
than triggering re-testing through a
narrative description of a process
change. Another alternative is to require
the claimant to notify the implementing
authority that a process change has
occurred and to certify that the
exemption criteria continue to be met if
the claimant determines that the waste
still maintains its exempt status. The
Agency is taking comment on how
process change should be defined in the
event one of the alternatives is chosen.
It should be noted that if waste for
which an exemption has been claimed
at any time tests above exemption
levels, that waste and all subsequently
generated waste is hazardous. The
claimant could not assert a new exit
claim until a new batch of waste tests
below the exit levels. The exemption
proposed today would not relieve
generators of their responsibility under
§ 262.11, nor would any test data
previously obtained prevent a claimant
from failing to satisfy the exemption
criteria should an inspector conduct
waste sampling that establishes
hazardous constituents at
concentrations above exit levels.
C. Public Participation
As a self-implementing exemption
effective upon receipt of the notification
by the implementing authority, there is
no decision prior to exit being made by
the implementing authority regarding
the waste. The opportunity for public
participation in an exemption claim is
the opportunity that exists at all times
for the public to bring to the
implementing authority's attention any
circumstance that might aid that
authority in its monitoring and
enforcement efforts. The public,
furthermore, would have the ability to
bring a citizen suit for a claimant's
failure to comply with any requirement
of the exemption.
The Agency is proposing to require
that the public be notified by the
claimant that an exemption claim is
being asserted. This notification would
be accomplished by publication of a
notice in a major newspaper, local to the
claimant and of general circulation, that
contains the information required by the
regulations. Evidence that the notice has
been submitted for publication must be
part of the notification package
submitted to the implementing facility.
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The Agency is requesting comment on
whether such a notice should be placed
in a newspaper local to the claimant's
facility or to the disposal facility or
both, should those facilities be located
in different areas not served by the same
newspaper.
Requiring notification of facilities
receiving exiting wastes has also been
raised to the Agency in discussions. The
Agency solicits public comment on the
need for and possible approaches to
requiring that waste generators that are
exiting their listed waste, notify
receiving facilities that wastes are HWIR
exited wastes. Additional discussion of
this issue appears in the docket under
"Receiving Facility Notification
Process."
As discussed above, the Agency is
also taking comment on whether
providing a "delay" in the effective date
when the exemption attaches (e.g., 30 or
60 days) would provide a significant
and meaningful opportunity for public
comment prior to the waste having
exited the subtitle C system. Possible
benefits of a waiting period before
effectiveness of the exit could include
greater opportunity for State review or
citizen comment before waste is actually
disposed outside of Subtitle C. Under
sucn an approach, the waiting period
would begin with receipt by the State of
a complete certification package, and
would run for the designated time (30
or 60 calendar days).
The Agency is taking comment on
whether access to claim documentation
through the appropriate implementing
agency \vill be sufficient to provide
public access to documentation. One
alternative would be to require the
claimant to provide access to the
information. If that option is selected,
the Agency requests comment on how,
and for how long, the claimant should
bo required to provide access to the
documentation, and on what kind of
protection for CBI would be appropriate.
IX. Request for Comment on Options for
Conditional Exemptions
The Agency has at different times
considered contingent management
approaches to disposal of hazardous
wastes. Under such approaches, wastes
that would be considered hazardous if
managed in an uncontrolled manner,
could be considered non-hazardous if
managed in a sufficiently controlled
manner. The following section discusses
and requests public comment on several
approaches to setting higher exit levels
tied to meeting certain management
requirements. These approaches would
allow wastes with higher concentrations
of hazardous constituents to be managed
safely outside of Subtitle C.
Many Subtitle C requirements were
written generically to address all
hazardous wastes and, consequently,
provide protection for those wastes that
pose the greatest risks. Others are either
explicitly or implicitly technology-
based rather than risk-based. Some of
these requirements are statutory and
cannot easily be adjusted to take risk
into account. Nevertheless, EPA
generally believes that it would be
desirable to tailor waste management.
requirements to more closely coincide
with risks. The exit levels proposed
today take an initial significant step in
this process by allowing very low-risk
hazardous wastes to be exempt from
Subtitle C requirements, leaving them
subject only to less prescriptive federal
and state controls for nonhazardous
wastes. They also take an initial step
towards setting different exit levels for
different situations by recognizing that
wastewater and non-wastewaters are
typically handled in different ways and
pose different risks, hence today's
notice proposes different exit levels for
wastewaters and non-wastewaters.
Within the time constraints imposed
by the court-ordered deadline for this
proposal, EPA has begun exploring
whether it would be possible to create
additional exemptions to allow'more
flexible management of additional
wastes now classified as hazardous
without compromising protection of
human health and the environment.
These options are premised on the
theory that a waste's risk is due not only
to its chemical composition, but also the
manner in which it is managed, which
can greatly affect the amount of
chemical constituents that ultimately
reach a human or environmental
receptor. The multipathway analysis
prepared to support the exit levels
shows that the concentration at which a
hazardous constituent threatens human
health or the environment varies
significantly with the type of
management that a waste receives—
some forms of management appear to
present greater risks than others. The
following discussion presents the legal
framework for management-based
exemptions, and outlines in some detail
the options which EPA finds to be most
promising for rapid promulgation.
A. Legal Basis for Conditional
Exemptions
EPA originally interpreted RCRA's
definition of hazardous waste to focus
on the inherent chemical composition of
the waste and to assume that
mismanagement would occur so that
people or organisms would come into
contact with the waste's constituents.
See 45 FR 33113 (May 19,1980).
However, EPA even in the past tried to
consider "reasonable" mismanagement
scenarios, scenarios that where
reasonably likely or plausible even if
not proven to necessarily have occurred
or be typical for a specific waste.
However, after more than a decade of
experience with waste management,
EPA believes that it may no longer be
accurate or necessary to assume that
worst-case mismanagement will occur.
In recent hazardous waste listing
decisions, for example, EPA has
identified some likely
"mismanagement" scenarios that are
reasonable for almost all wastewaters or
non-wastewaters, and looked hard at
available data to then determine if any
of these are for some reason very
unlikely for the specific wastes being
considered, or if other scenarios are
likely given available information about
current waste management practices. As
a further extension of that logic, EPA
now believes it may be appropriate to
find that, where mismanagement is not
likely or has been adequately addressed
by other programs, EPA need not
classify a waste as hazardous and that
there may be ways to recognize
situations where the limitations on
likely "mismanagement" are specific to
a State, a type of waste, or a facility-
specific condition on how a waste is
managed.
EPA believes that it can interpret the
definition of "hazardous waste" in
RCRA section 1004(5) to authorize this
approach to classifying wastes as
hazardous. Section 1004(5)(B) defines as
"hazardous" any waste which may
present a substantial present or
potential hazard "when mismanaged".
EPA reads this provision to allow it to
determine the circumstances under
which a waste may present a hazard and
to regulate the waste only when those
conditions occur. Support for this
reading can be found by contrasting
section 1004(5)(B) with section
1004(5)(A), which defines certain
inherently dangerous wastes as
"hazardous" no matter how they are
managed. The legislative history of
Subtitle C of RCRA also appears to
support this interpretation, stating that
"the basic thrust of this hazardous waste
title is to identify what wastes are
hazardous in what quantities, qualities
and concentrations, and the methods of
disposal which may make such wastes
hazardous."H.Rep. No. 94-1491, 94th
Cong., 2d Sess.6 (1976), reprinted in A
Legislative History of the Solid Waste
Disposal Act, as Amended,
Congressional Research Service, Vol.1,
567 (1991) (emphasis added).
EPA also believes that section 3001 .
provides it with flexibility to consider
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66396 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
the need to regulate wastes as
hazardous. Section 3001 requires that
EPA, in determining whether to list or
otherwise identify a waste as hazardous
waste, decide whether a waste "should"
be subject to the requirements of
Subtitle C. Hence, section 3001 .
authorizes EPA to determine that
Subtitle C regulation is not appropriate
where a waste is not likely to be
managed in such a way that it will
threaten human health or the
environment. Moreover, regulation of
such waste under Subtitle C would not
appear "necessary to protect human
health or the environment" under RCRA
sections 3002(a), 3003(a) and 3004(a).
As noted elsewhere in this proposal,
EPA interprets these provisions to give
it broad flexibility in fashioning criteria
to allow hazardous wastes to exit the
Subtitle C regulatory system. EPA's
existing regulatory standards for listing
hazardous wastes also allow
consideration of a waste's potential for
mismanagement. See § 261.11 (a)(3)
(incorporating the language of RCRA
section 1004(5)(B)) and
§ 261.11(c)(3)(vii) (requiring EPA to
consider plausible types of
mismanagement). Where
mismanagement of a waste is
implausible, the listing regulations do
not require EPA to classify a waste as
hazardous.
Two decisions by the U.S. Court of
Appeals for the District of Columbia
Circuit provide potential support for
this approach to defining hazardous
waste. In Edison Electric Institute v.
EPA, 2 F.3d 438, (D.C. Cir. 1993) the
Court remanded EPA's RCRA Toxicity
Characteristic ("TC") as applied to
certain mineral processing wastes
because the TC was based on modeling
of disposal in a municipal solid waste
landfill, yet EPA provided no evidence
that such wastes were ever placed in
municipal landfills or similar units.
This suggests that the Court might
approve a decision to exempt a waste
from Subtitle C regulation if EPA were
to find that mismanagement was
unlikely to occur. In the ,same decision
the Court upheld a temporary
exemption from Subtitle C for
petroleum-contaminated media because
such materials are also subject to
Underground Storage Tanks regulations
under RCRA Subtitle I. The court
considered the fact that the Subtitle I
standards could prevent threats to
human health and the environment to
be an important factor supporting the
exemption. Id. at 466. In NRDC v. EPA,
25 F.3d 1063 (D.C. Cir. 1994) the Court
upheld EPA's finding that alternative
management standards for used oil
promulgated under section 3014 of
RCRA reduced the risks of
mismanagement and eliminated the
need to list used oil destined for
recycling. (The Court, however, did not
consider arguments that taking
management standards into account
violated the statute because petitioners
failed to raise that issue during the
comment period.)
B. Improvements in Management of
Non-Hazardous Waste and in Risk
Assessment Methodology
EPA's early regulations defining
hazardous waste reached broadly to
. ensure that wastes presenting hazards
were quickly brought into the system.
When EPA promulgated its first listings
and characteristic rules in 1980, its
knowledge of toxic constituents,
constituent transport pathways, and
waste management options was more
limited than it is today.
In addition, significant changes and
improvements in waste management
have occurred since the early 1980's.
Many states have established or
strengthened industrial nonhazardous
waste programs since that time. For
example, currently 26 states require
liners and 28 states require ground-
water monitoring for at least some
surface impoundments. Up to 45 states
require ground-water monitoring and 38
states require liners for at least some
landfills. It is important to recognize
however, that within a state, applicable
requirements may vary according to a
number of factors, including unit type,
waste source, and location. See "State
Requirements for Industrial Non-
Hazardous Waste Management
Facilities" EPA 1994. At the same time,
industries have gained experience in
managing wastes and many have
improved waste management practices
under incentives such as public access
pursuant to the Emergency
Preparedness and Community Right to
Know Act, and avoiding liabilities
under Superfund, RCRA corrective
action and state cleanup programs.
EPA's ability to predict the risks that
a waste may pose has also improved
significantly. EPA has collected much
more data on a variety of waste
management units and other factors that
impact the ability of waste constituents
to reach a receptor. Models such as the
EPACMTP and the models used in the
multipathway analysis provide more
sophisticated means of assessing the
risks of a range of waste management
options. As a result of all these changes,
EPA is now in a position to begin to
implement a more carefully tailored
risk-based approach to regulating
hazardous wastes.
C. Overview of Options for Conditional
Exemptions
The Agency has identified several
different approaches to providing
conditional exemptions that would
allow more wastes to exit the Subtitle C
system. These options fall into two
broad categories: (1) Establishing
national conditional exemptions based
on unit type either with or without
assuming additional management
controls; and (2) granting conditional
exemptions to qualified state programs
that ensure additional management
controls.
1. National Approach: EPA Would
Establish National Exit Levels for
Contingently Managed Waste
The contingent management program
could be adopted by any state that
wants to implement it, without
consideration of state programs for non-
hazardous waste. The contingent exit
levels would differ according to the
degree of management/disposal
restrictions imposed as a condition of
exit. The possible options would
include progressively more restrictive
requirements, and allow progressively
higher exit levels as disposal options are
further restricted. The options under
this approach are:
a. Distinguish Between Disposal in Land
Application Units and Other Units
The multipathway risk assessment
methodology used for this rulemaking
takes into account management
scenarios (such as land treatment of a
waste), or exposure pathways (such as
wind transport from an uncovered pile
or volatilization from an open tank),
resulting in calculated exit levels based
on the riskiest scenario. In some cases
this exit level may be significantly lower
than the next most risky exposure
pathway. The riskiest exposure pathway
may not be applicable to some
management situations. On review of
the risk analysis results, the Agency
determined that disposal in a land
application unit is frequently the
highest risk disposal option in both the
multipath and groundwater. modeling.
As described in detail in Section X.
below, the Agency has developed for
proposal an approach to contingent
management relying on the
multipathway exposure analysis, risk
level of 10-6 and HQ of 1, and using the
base case uncontrolled management
scenarios, but with land application
units removed from the analysis. Exit
concentrations would still be protective
across a wide variety of conditions
nationally, for all non-land application
unit disposal. The Agency is proposing
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one national exit level for each
constituent based on the next riskiest
pathway, on condition that wastes are
not disposed in land application units.
This option was considered by the
Agency to be the simplest approach to
contingent management. It would be
somewhat easier to enforce than other
options described below, since there
would still be only one conditional exit
level for each constituent.
Implementation mechanisms to assure
that the wastes go only to allowable unit
types are described below.
b. Unit-Specific Exit Levels for Each
Disposal
Another approach to contingent
management considered by the Agency
would be to establish a set of exit levels
for each waste management unit
evaluated based on risks at unregulated
units of that type. Units that would be
evaluated, at HQ1 and 1E-6 risk,
would be land application units, waste
piles, landfills, surface impoundments
and tanks. Base case assumptions would
bo used to describe the units. The
Agency has not included specific exit
levels for this approach here, but solicits
comment on its potential benefits, and
potentially greater complexity of
implementation and compliance
assurance.
Under option 2 the Agency would set
separate exit levels for each type of
waste management unit. Generators
would be allowed to choose the type of
non-subtitle C waste management unit
in which to manage their waste, and
would be required to meet the unit-
specific exit levels for all constituents in
order to manage the waste in that unit.
Testing and implementation would be
similar to the requirements for exit
based on the most limiting pathway.
However, the Agency believes this
option would increase the complexity of
tracking wastes that met the varying
concentration exit levels tied to specific
allowable units.
The Agency believes allowing use of
exit levels tailored to waste management
can be a practical and appropriate way
to allow greater volumes of waste to exit
Subtitle C without increasing risks to
above the toxicity benchmarks
described in Section IV.D, providing
that characteristics of various waste unit
types can be clearly defined (such as the
difference between surface
impoundments, tanks, and perhaps
covered tanks for the management of
wastewaters), and providing the Agency
can design a viable implementation
scheme that does not rely primarily on
statements of proposed future disposal.
Tracking and monitoring of actual waste
management could be one way to assure
disposal in the appropriate facilities.
Limiting disposal to on-site facilities
could also better assure proper disposal,
although this would limit the usefulness
of contingent management approaches.
The Agency requests comment on
additional implementation requirements
that might be needed to assure the waste
is managed in the designated unit type
only.
EPA has not developed this as a
general approach in this rulemaking
because the risk modelling that was
done, while more multifaceted and
comprehensive than many past
analyses, was not designed for this
purpose. For efficiency in modelling,
EPA did not always model each
pathway for each specific unit. EPA
sometimes only modelled an exposure
pathway of concern (such as air
emissions) from certain types of units
that EPA thought might be the limiting
scenario, and risk from organic
constituents in a landfill were not
modeled. Therefore the modelling work
to date may not identify the most
limiting pathway if each unit is judged
individually. To fully develop exit
levels for a full range of unit types, EPA
believes it would have to do
supplemental risk analysis to fill in the
gaps in modeling for each of the waste
management units, or at least evaluate
whether the risk analysis done to date
is sufficiently representative. Tables 21-
39 in the November 1995 Supplement to
the multipath analysis present the
modeled risk values for each constituent
disposed in each of the five options
modeled, and for each pathway. These
tables can aid commenters in
understanding what a unit-specific exit
value for any particular constituent
could be.
c. Consideration of Additional
Management Unit Design or
Management Practices
A third option is that EPA would use
a somewhat modified multipathway
exposure model to evaluate whether
adding additional specific design or
operating controls for particular unit
types, would allow less conservative
exit levels. These conditional exit
concentrations would be promulgated
on a unit-type specific basis, and could
be used only by units employing the
specified additional controls that would
reduce the risk level to 10-6. Such an
approach could be self-implementing
for a facility owner/operator, and would
not necessarily be tied into a permitting
authority.
While such an approach could take
into account the. effects of a combination
of added controls on each unit type
(such as size of the unit, ground-water
monitoring, liners, caps, etc.) the
Agency believes that there are a number
of significant implications associated
with this approach. It could be
interpreted by industries and states as
an indirect way to define a broader set
of management standards for industrial
non-hazardous waste management
units. Also, if the approach were self-
implementing, it could be extremely
difficult to ascertain that a particular
unit meets a complex set of controls and
therefore to assure compliance with the
conditional exit levels. The more
complex a judgement required to
determine compliance with the
conditions (such as whether a liner that
is hard to inspect during operation is
properly installed and protected from
tears), the more appropriate it is likely
to be that such determinations be made
in the context of a permitting authority
or prior approval rather than as a
condition on a self-implementing
exemption.
As a variation on this approach, The
Agency could take into account certain
regional, local, or site-specific factors in
establishing exit levels. These could
include the effect of local rainfall,
regional hydrogeology, or size of facility
on exit values. These issues are
described in greater detail in section 3
below.
Because of the complexity of
implementation, the Agency would
attempt to define very limited
additional control(s) to limit exposures
and reduce risks to 10-6 level. EPA
particularly asks for comments on unit
design attributes that are easily
ascertainable in a spot inspection versus
those that require more detailed
engineering review, or review or
monitoring of operations. For this
option, as with options one and two, the
Agency would have to conduct
additional risk modelling work to
adequately evaluate additional
parameters on a unit specific basis.
One issue common to all of the
options discussed above is the legal
status of wastes subject to such
conditioned exemptions when there is a
violation of the conditions. The Agency
requests comments on how to make
them enforceable in a practical way that
is fair to those involved. If the waste
concentration/unit requirements are
conditions of an exemption, any
violation of a condition means that the
waste generator, or other individual. .
managing the waste, has violated the
full range of RCRA requirements and
has been illegally managing a
"hazardous waste" as a "nonhazardous"
waste. Because the conditional
requirements are not clearly tied to,
other non-hazardous waste authorities,
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there would not be a remedy for the
violations outside of the hazardous
waste program. An alternative approach
is discussed in the following options
allowing conditional exit levels in states
with qualified industrial non-hazardous
waste programs. As long as the state has
clear enforcement authority under its
non-hazardous waste management
program, these conditions could be
crafted so that a violation of the
condition was not illegal disposal of
hazardous waste involving multiple
RCRA counts. Rather it would be
enforced as a violation of the relevant
State authorities. The Agency requests
comment on the advantages and
disadvantages of these approaches, as
well as whether there might be other
approaches to ensure adequate legal
remedies for violations of the
conditional exit requirements, when the
contingencies are not based on qualified
state industrial non-hazardous waste
programs.
2. State Program Approach
As noted earlier in this section, many
state industrial non-hazardous waste
programs have improved significantly
since the early days of Subtitle C. State
programs may offer the advantages both
of requiring management controls which
ensure protection of human health and
the environment and ongoing oversight
on a facility specific basis through
permitting, inspection and enforcement
activities. While every state program
may not be operating at the same level,
the Agency believes that a number of
state programs may offer reasonable,
protective systems to serve as the basis
for less stringent exit levels. Qualified
state programs would be allowed to
manage listed waste in their non-
hazardous waste management program
under certain conditions. These
qualified state programs would ensure
that risks were reduced to protect
human health and the environment.
There are three key factors the Agency
believes would need to be considered in
establishing state-based contingent
management programs. These are (1)
establishing a risk-based cap on waste
constituent concentrations that can be
managed contingently; (2) the type of
program review of a state program that
EPA would perform to identify qualified
state programs, and (3) the breadth of
state program controls.
For the risk cap, the Agency has
considered using either a 1 E-4 cancer
risk and HQ1, or 1 E—3 cancer risk and
HQ10 as options. The caps would be
modeled based on. management in
unregulated disposal facilities, as in the
base-case exit level modeling.
Regarding program review, the
Agency would either conduct a
qualitative review of the State program,
examining it to ensure it addresses key
considerations, or would require states
to conduct quantitative risk assessment
of planned management practices to
demonstrate their safety down to 1 E—
6 cancer risk and HQ 1 or an alternative
risk target.
For the qualitative review, EPA would
specify environmental and
administrative performance goals and
the state would have to submit a
narrative description demonstrating
how the particular combination of
technical standards and administrative
requirements in their program protects
human health and the environment and
meets those performance goals, for
example:
• Ground-water protection: A state
program must address adequately
contamination of groundwater from a
facility.
• Surface water protection: A state
program must address adequately
prevention of contamination of surface
water which may occur through the run-
off of pollutants from the disposal
facility to surface waters.
• Address other environmental and ,
performance goals such as controlling
air exposures, siting, ensuring long-term
integrity of the site, etc.
• Permitting and enforcement
authorities and public participation: A
state program has appropriate
authorities and a system for prior
approval of waste management
facilities, and public participation either
on a site-specific basis or for input to
development of class permits.
• Adequate resources: A state
program has adequate resources for
administration of the program including
permitting, inspections and
enforcement.
Under a quantitative risk review
approach, a state would have to
document their permitting and
enforcement authorities and public
participation requirements, as well as
the adequacy of their program resources.
The state would also have to
demonstrate to EPA how the particular
combination of technical management
controls or design standards in its
industrial non-hazardous waste program
would ensure meeting 10—6 risk levels.
In order to do this, EPA would have to
refine or expand the multipathway
exposure model. EPA would then either
make its multipath model available to
states or work with them to demonstrate
that unit-specific state program controls
would meet the 10—6 risk level for a
particular class of facilities receiving
conditionally exited wastes. The Agency
solicits public comment on whether
states can propose alternative risk
targets for use in state contingent
management programs.
Regarding program breadth, the
Agency believes either broad, state-wide
programs, or more narrowly focused
contingent management programs could
be developed. Under a broad-based state
program approach, the Agency would
approve as qualified only those state
subtitle D programs that adequately
regulate all state non-hazardous waste
management and wastes. Under this
approach, states with programs deficient
in certain aspects would be required to
upgrade before participating in the
contingent management program.
However, the Agency recognizes that
state subtitle D programs vary widely in
the particular units and waste types that
are covered, among other factors.
Therefore, as an alternative approach,
EPA might determine that a program
qualifies for conditional exit only for
particular units (i.e. for landfills only, or
for landfills and surface impoundments,
etc.). In other cases, a state program
might focus narrowly on developing
appropriate contingent management for
particular waste streams generated by
key industries in the state.
In considering how to use these key
factors in developing contingent
management regulations, the Agency
identified three options in addition to
the three options described above under
the national programs. These will be
identified in this discussion as options
four, five and six.
Under option four, the Agency would
use the 1 E—4 and HQ 1 risk cap on
waste and would conduct a qualitative
review of the state program using the
criteria described above. This could be
done either on a narrow program basis,
or based on a program that qualifies
broadly.
Under option five, the Agency would
also use the 1 E—4 and HQ 1 risk cap
for waste being contingently managed,
but would require that states conduct
risk modeling of proposed disposal to
demonstrate that risks from the waste as
disposed would be not greater than the
1E-6 and HQl risk targets of the base
case. This approach could be taken
either with the entire state program, or
only certain waste management
practices. In particular, site-specific
factors, as described below, could be
considered under this approach. These
could include facility size, local rainfall,
or local hydrogeology, among others.
Location of the nearest drinking water
well might also be considered by the
state in evaluating risks, if allowed
under state regulations and regulatory
policies. In this case, the state would be
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required to demonstrate to EPA, using
tho multipathway analysis or another
risk assessment model, how they would
ensure on a site-specific basis that
facilities disposing of conditionally
exited wastes meet a 10-6 risk level.
Development of this approach might
also require quite different risk models,
since the multipathway model as it
currently exists incorporates a number
of simplifying assumptions to capture a
broad range of possible conditions. The
Agency would have to ensure that a
model used for this analysis can
incorporate complex site-specific
variables, or develop a set of simplified
models that could be applied by states.
However, this approach would provide
maximum flexibility to states and
generators to tailor exit levels to
particular waste and site characteristics.
Under option six, the Agency would
allow wastes posing up to 1E-3 cancer
risk and HQ10 (in an unregulated
management setting), and allow either a
qualitative or quantitative review of the
state program, but allow participation
only by state programs that are broadly
qualified, i.e., that are qualified in all
aspects of the program, for currently
managed industrial non-hazardous
waste. The Agency would be more
comfortable with this approach because
it would be more assured of safe
management of the waste regardless of
where in the state it is disposed.
The Agency also solicits public
comment on whether more than one of
the options discussed above should be
developed at the same time. For
example, the Agency might establish
both the option 1 proposal described
below, and establish a state-based
contingent management program based
on any of options four, five or six. By
doing so, the Agency would estabh'sh
option 1 as a minimum national
standard, but this approach would allow
that states to go further they choose to
do so.
3. Establish Exit Levels That Consider
Regional or Site-Specific Factors That
Might Affect Constituent Fate and
Transport'
In addition to facility design factors,
there are other location-specific factors
that may substantially affect the risks
and the appropriate exit levels for waste
management units. Examples of such
factors include: Rainfall and
hydrogeology at the site and the
distance to off-site receptors. The
average amount of precipitation falling
on these waste management units may
affect both the amount of leachate to
groundwater and soil run off to off-site
receptors. Thus, the Agency could
determine geographic regions based
upon climatic zones, could require
precipitation data from the most
appropriate certified rain gauge, or
could require site specific precipitation
information. However, in order to do
this the Agency would need to verify
that the other model inputs are
appropriate for each of the regions or
else develop new region-specific inputs.
Therefore, the Agency solicits data and
comment on technically appropriate
ways to establish exit levels based on
rainfall levels.
Other site-specific factors that may
significantly affect the groundwater
pathway are the hydraulic conductivity
of the soil surrounding the waste
management unit and the distance to
the nearest drinking water wells. If the
hydraulic conductivity of surrounding
soil is relatively low—such as in soils
dominated by clays—then the flow of
any potentially contaminated leachate
to ground water could be effectively
retarded for long periods of time
(though flow to surface waters or other
pathways might change, perhaps
increasing). Landfills located in soils
with low hydraulic conductivities (for
example, 10-6 cm/sec or lower) could
provide an extra level of environmental
protectiveness for ground water that
could be considered in developing this
approach. For example, the Agency
might address this effect by developing
exit levels corresponding to different
classes of hydraulic conductivity.
Alternatively, differences in hydraulic
conductivity could be considered
through a site-specific process. This
approach would not be relying on
engineered controls, but on natural
attributes of the location. EPA solicits
comments on whether such attributes
can be readily determined or in what
circumstances they can be readily
determined and relied upon.
The Agency did some limited
sensitivity analysis with respect to
ground water risk modelling to look at
the concept of developing different exit
levels depending on broad
hydrogeological regions. The results of
that analysis are in the docket. The
Agency requests comment as to the
value of investing in this approach and
practical considerations the Agency
should weigh in deciding whether to
pursue this approach.
Finally, where the nearest drinking
water wells are at an unusually great
distance from the waste management
unit, corresponding exit level
concentrations associated with
groundwater exposures that took that
distance into account could be
significantly lower if the Agency's goal
were solely the prevention of current
exposure to groundwater contamination.
However, many states have policies to
not degrade groundwater and EPA
believes it is quite difficult to predict
future needs for uncontaminated
groundwater. EPA believes that the
groundwater modelling done for this
rule reflects a balanced view by using
the distribution of nearest wells.
However, EPA expects it will receive
comments suggesting that it should
consider allowing facilities with no
moderately nearby drinking water wells
to take that into account. The Agency
seeks comment on the implementation
issues associated with taking these
factors into account and the related
policy judgement as to whether the goal
of more site-specific assessment should
be prevention of risk based on current
ground water use, reasonably
foreseeable use, or based on distances
that would be more protective of the
potential future use of ground water.
The Agency also seeks comment on
other location-specific factors or
combinations of factors that may be
particularly important in mitigating the
risks associated with waste disposal.
The Agency also requests comment on
alternative approaches for taking these
location-specific factors into
consideration in developing exit levels
for waste management. One option for
doing so would be to develop additional
tables of exit levels (in addition to
Option 2) for waste management units
that reflect the effect of some of the most
important location-specific factors (e.g.,
exit levels for areas with low annual
rainfall, or indexed to landfill size). As
an alternative option, the Agency could
develop "reduced form" equations that
specifically relate the exit level
concentration to critical location-
specific factors (such as annual rainfall).
The Agency requests comment on the
merits of these approaches and on
alternative options that might be used to
better accommodate the effect of
location-specific factors on exit levels.
D. Land Disposal Restrictions for
Contingent Management Options
Any conditional exemption would
offer much more significant relief if it
eliminated or reduced the need to
comply with more stringent LDR
treatment requirements. As explained
above in Section VI of today's proposed
rulemaking, however, under Chemical
Manufacturers Association v. EPA (the
"Third Third" decision) LDR treatment
standards generally continue to apply
even if a waste ceases to be classified as
a hazardous waste. If an LDR treatment
standard were lower (more stringent)
than a contingent management exit
level, the waste would still need to meet
the LDR standard.
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66400 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
EPA has proposed two approaches to
integrating HWIR exit levels and LDR
treatment requirements for the base
option. First, EPA is proposing that LDR
treatment requirements will never apply
to wastes that meet all applicable exit
levels at the point of generation.
Second, for wastes which meet exit
levels subsequent to the point of
generation and, consequently, remain
subject to the LDR regime, EPA is
proposing to allow some exit levels to
serve as alternative risk-based treatment
standards meeting the "minimize
threat" standard'under RCRA section
3004(m). EPA expects these proposals to
reduce the burden of complying with
LDR requirements.
As explained more fully in the
detailed presentation of option 1 below,
EPA is proposing both of these
approaches for contingent management
option 1 (relaxed exit values for wastes
that are not placed in land application
units). EPA's rationales are set out in
that discussion.
EPA anticipates that it might also be
willing to propose to use exit levels
developed under option 2 (separate exit
levels for each major type of waste
management unit) to serve as risk-based
"minimize threat" standards. If EPA
filled the gaps in its current
multipathway risk assessment, it would
feel fairly confident that the
multipathway analysis plus the
groundwater analysis identified
constituent concentrations that
minimize threats to human health and
the environment for each class of waste
management units. The modeling for
both analyses would assume each type
of unit was located in a "reasonable
worst case" physical setting and was
subject to minimal management
controls. EPA, however, would expect
some members of the public to argue
that unit-specific exit levels should not
be considered "minimize threat" levels
because risks to human health and the
environment would not be minimized if
exempted waste ended up in the wrong
type of management unit. EPA might try
to address such concerns by imposing
conditions such as tracking or reporting
systems on persons claiming the
exemptions.
EPA would expect similar objections
to the option of allowing wastes that
meet option 2 levels to exit if their
constituent concentrations met unit-
specific exit levels at the point of
generation. Members of the public might
again be concerned about the possibility
that wastes could be placed in a unit
type requiring lower (more restrictive)
exit levels. As suggested above,
however, EPA could impose conditions
to help ensure that exempted waste goes
only to a unit where the exit levels in
fact minimize threats.
Providing LDR relief for the remaining
options for conditionalexemptions
would raise additional legal and
practical issues. All of the remaining
national and state-based options rely on
design or operating controls (such as
liners) to help prevent dangerous
concentrations of hazardous
constituents from reaching human or
environmental receptors. EPA, for
example, would be reluctant to take into
account control measures that would be
difficult for inspectors to verify during
site visits.
It might be somewhat easier to take
into account factors—such as annual
rainfall, depth to groundwater, and
subsurface soil and rock formations—
that relate to a unit's physical setting.
EPA has already proposed to interpret
section 3004(m) to allow consideration
of a unit's physical setting in making
site-specific minimize threat findings.
See the proposed LDR standards for
contaminated soil, 58 Fed. Reg. 48123
and 48155 (Sept. 14,1993). EPA
requests comments on all of these issues
related to the integration of conditional
exemptipn options to the LDR
standards.
E. Contingent Management of Mixed
Waste
The Department of Energy (DOE) has
also expressed interest in EPA's
contingent management approaches to
managing waste that is mixed radiologic
and RCRA hazardous waste ("mixed
waste"). Mixed waste may be managed
by DOE-regulated facilities or
commercial facilities regulated by the
Nuclear Regulatory Commission (NRC).
EPA expects that the general approach
in today's proposed regulation would be
applicable to mixed wastes as well as
listed-only hazardous wastes. DOE has
suggested that because mixed wastes
subject to RCRA are also subject to AEA
disposal requirements which control
releases of and exposure to radioactive
hazards, these AEA requirements may
address releases of chemically
hazardous constituents as well, and it
would be reasonable to allow more
mixed wastes to exit Subtitle C because
of the AEA requirements. DOE believes
these AEA requirements would also
provide adequate protection of human
health and the environment from
chemically-hazardous constituents. DOE
has submitted several studies to EPA in
support of their views, and the Agency
has placed those documents in .the
public docket for review. The Agency
will also undertake a review of these
data to better understand the additional
increment of protection provided by
AEA low-level waste site performance
standards. With that review ongoing, the
Agency is proposing, and requesting
public comment on, adaption of option '
four above to DOE's special
circumstances. The Agency requests
comment on allowing mixed waste
meeting conditional exit levels for
chemical toxicity estimated at 10-4
cancer risk and HQ1 (modeled at an
uncontrolled site), to exit Subtitle C if
managed in AEA disposal facilities.
DOE has also urged the Agency to
consider establishing a categorical
exclusion from RCRA requirements for
mixed waste debris that is immobilized.
One of several macro- or
microencapsulation methods could be
used to immobilize the debris, including
use of portland or other cement
products, or various polymer products.
Under such an exclusion, all
immobilized mixed debris could be
managed outside of Subtitle C, but
would still be required to be disposed
in AEA disposal facilities. No testing of
the debris would be required to identify
toxic constituents or the levels at which
they might be present. DOE has
conducted a study of leaching rates for
certain toxic constituents from
stabilized debris and submitted it to the
Agency for review in support of DOE's
conclusion that immobilized debris can
be managed safely outside, of subtitle C
if disposed in an AEA facility. Because
the Agency has only recently received
this study, it has been unable to
adequately review and evaluate the data
presented. The Agency solicits public
comment on this approach, the DOE
study, and solicits any other available
data that are relevant to this topic.
Finally, DOE has developed data on
vitrified waste, and requested that the
Agency consider the environmental
protection conferred by this treatment
process. Again, the Agency has not had
adequate time to review and evaluate
the DOE data, but has placed it in the
public docket and solicits public
comment on the data and DOE's
preferred approach to mixed waste
management.
In soliciting comment on these exit
procedures for mixed waste, the Agency
recognizes that a number of states
hosting DOE facilities have expressed
concern over the proposal's effect on
their states ability to adequately regulate
mixed waste under states and federal
law as intended by RCRA and the
Federal Facilities Compliance Act.
These states also believe that significant
details of the DOE proposal are lacking
and additional analysis would need to
occur before the procedures can receive
adequate comment. Therefore, the
Agency intends, to the extent consistent
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with the schedule negotiated in the
consent decree for this rulemaking, to
publish a supplemental proposal on
HWIR mixed waste exit criteria after
initial comments have been received.
The supplemental proposal would
further describe the regulatory options
boing considered and will solicit
additional comment on more specific
options.
X. Implementation of Conditional
Exemption Option 1
A. Introduction
Using the concept of contingent
management, EPA is proposing to create
a second, alternative set of exit levels for
nonwastewaters that are managed in
landfills or monofills, but not land
treatment units. Persons wishing to
utilize this alternative exit scheme
would not only have to meet the
recalculated concentration limits for all
constituents hi their wastes, but also
comply with conditions prohibiting
land treatment. Compliance with
notification and tracking requirements
described in more detail below will also
be necessary. The exit levels for this
alternative are set out in appendix XI of
40 CFR part 261; the requirements and
conditions are set out in proposed
§ 261.37. Nonwastewaters that do not
meet the exit levels in appendix X to 40
CFR part 261 will be eligible for exit
only if they meet the more relaxed
levels in appendix XI of 40 CFR part 261
and comply with all relevant
conditions.
EPA derived the levels for this
alternative by deleting all of the
modeling results for the land treatment
scenario from its risk assessment data
base, and selecting the lowest remaining
exit value from the remaining modeling
results for other types of waste
management units. The same approach
used to establish exit levels presented in
Section V. of today's proposed
rulemaking was used to establish exit
levels under this option. That is, where
complete risk data was not available,
surrogates were used to extrapolated
exit levels (see Section IV.H) and where
analytical limitations existed, EQCs
were used as exit levels (see Section
IV.I). As a practical matter, this
approach affects only the exit levels for
nonwastewaters. As explained above in
section IV, EPA created the original exit
levels for nonwastewaters by grouping
the modeling results for the unit types
typically used to manage solid materials
(ash monofills, piles, and land treatment
units) and selecting the lowest value
from all pathways modeled for these
scenarios. EPA created the separate
wastowater exit levels by grouping the
results from units typically used to
manage liquid wastes (tanks and surface
impoundments). Consequently, the
wastewater exit levels are not based on
the modeling of land treatment units,
and these levels are not affected by the
decision to exclude results from the
land treatment scenario.
The Agency is proposing that the
contingent management exemption be
self-implementing. Therefore, the
claimant would have the burden of
demonstrating that all of the provisions
for the contingent management
exemption described herein have been
met. In an enforcement action, a waste
for which a contingent management
exemption is claimed would be
considered a Subtitle C hazardous waste
unless the claimant was able to produce
evidence that all of the conditions of the
exemption have been met.
B. When Contingent Management
Exemptions Become Effective
The Agency is proposing two options
for the point at which the contingent
management exemption would become
effective.
1. Option 1A—Placement of the Waste
in a Qualifying Unit
Under the first option, the conditional
exemption for "contingent
management" nonwastewaters would
not become effective until the waste had
been placed in a qualifying unit. Prior
to actual disposal, the nonwastewater
would be managed as a hazardous waste
according to all applicable RCRA
provisions, including 40 CFR parts 262
(for generators) and 263 (for
transporters) and part 268 (regarding
treatment prior to land disposal). These
requirements include compliance with
the waste manifest provisions of 40 CFR
part 262, subpart B, and the pre-
transport provisions of 40 CFR part 262,
subpart C, which contains, among other
provisions, the provisions governing
hazardous waste accumulation.
Treatment and storage prior to disposal
would remain subject to parts 264, 265,
and 270.
The Agency believes this approach
makes it easier to ensure consistent
implementation and safe management of
the waste. It also decreases the potential
implementation concerns that may arise
if some states adopt this rule as part of
their authorized programs and others do
not. For example, this approach would
reconcile transportation concerns that
could arise if waste, conditionally-
exempt in one state, were transported
through a state that had not adopted the
contingent management exemption as
part of its authorized program.
Under this option, the Agency is
considering and requesting comment on
the applicability of amending 40 CFR
264.1 and 265.1 to allow off-site
disposal facilities to store candidate
contingent management exempt wastes
for up to 10 days without becoming a
subtitle C treatment, storage, and
disposal facility, prior to ultimate
disposal in a monofill or landfill. The
Agency requests comment on whether
10 days is a sufficient or appropriate
length of time, and if not, what time
period may be appropriate.
Under the above approach, contingent
management exempt nonwastewaters
being disposed of on-site also would not
become exempt until placed in a
disposal unit meeting the requirements
established under this rule. However,
since the current waste accumulation
provisions of 40 CFR 262.34, allow a
generator to store hazardous waste on-
site in tanks, containers or containment
buildings for 90 days without becoming
a Subtitle C storage facility, EPA
believes that this approach should not.
place undue burdens on a generator.
EPA requests comment on whether
§ 262.34 will in fact enable generators of
exempt nonwastewaters to store wastes
on-site in unpermitted units for a
reasonable period of time prior to land
disposal. EPA acknowledges that
nonwastewaters are typically-not stored
in tanks.
2. Option IB—Effective Upon Meeting
the Exit Levels
The second option that EPA is
considering would allow a
nonwastewater to become exempt from
all hazardous waste requirements except
part 268 as soon as it meets appendix XI
of 40 CFR part 261 exit levels and the
claimant has met all the requirements
and conditions of the exemption,
including certifying that the waste will
be managed in a monofill or land
disposal unit. The goal of this approach
is to ensure nonwastewaters will not be
managed in a land treatment unit,
which was found to pose the greatest
risk for many routes of exposure. Under
this approach, storage, treatment and
transportation of the nonwastewater
could take place outside of Subtitle C
control upon meeting the'requirements
and conditions for the exemption. If
EPA were to adopt such an approach, it
would impose conditions to ensure that
the exempted nonwastewater reached
the types of units for which the
exemption was designed. Various
options are suggested below in Section
D.I.
Finally, EPA notes that the proposed
approaches have different implications
for LDR relief. These differences, which
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principally concern the availability of
LDR relief for nohwastewaters which
meet the appendix XI of 40 CFR part
261 exit levels at their point of
generation, are discussed in more detail
in section H. below.
C. Requirements for Obtaining an
Exemption
The following requirements would be
applicable to both of the approaches
discussed above. Requirements for
meeting the contingent management
exemption would include the sampling
and testing requirements of § 261.37
(b)(l), the public notice requirements of
§ 261.37 (b)(3) and the notification to
the implementing Agency requirements
of § 261.37 (b)(4), similar to those
respective requirements for the base
exemption in §§ 261.36 (b) (1), (3) and
(4). The Agency notes that these
provisions would be directly
enforceable Subtitle C requirements
imposed prior to obtaining an
exemption rather than conditions for
maintaining the exemption.
1. Sampling and Testing Requirements
for Contingent Management Exemptions
The Agency is proposing that the
sampling and testing requirements for
the contingent management exemption
be the same as those proposed for the
base exemption in Section 261.36 (b)(l).
The Agency requests comment on
whether the sampling and testing
requirements for the base exemption
would be appropriate for the contingent
management exemption.
2. Requirements for Public Participation
in Contingent Management Exemptions
To provide the public with access to
information, the Agency is proposing to
require compliance with the public
notice requirements in proposed
§ 261.37(b)(3), similar to those in
§ 261.36(b)(3). The first time a claimant
provides the Agency with notification of
an exemption claim for contingent
management wastes, he will be required
to publish a notice of the claim in a
major local newspaper general
circulation. The notice must include the
name and address of the facility, the
description of the waste {as contained in
the notification), a brief general
description of the process producing the
waste, an estimate of the quantities of
waste claimed to be exempt, and
information about the Agency where the
claimant has sent the notification and
supporting information, hi addition, the
public notice must include that the
waste meets the contingent management
exemption levels in appendix XI of 40
CFR part 261 and that the waste will be
disposed of in a monofill or land
disposal unit.
3. Notification Requirements for
Contingent Management Exemptions
To qualify for a contingent
management exemption, a claimant
would need to submit to the authorized
State Agency Director a formal
notification of its claim that waste meets
the contingent management exemption
levels in Appendix XI of 40 CFR part
261 and will be managed in accordance
with the management conditions. In
addition to the requirements under
§ 261.36 (b)(4), the contingent
management exemption notification to
the implementing Agency must include
an accompanying certification that the
waste meets the contingent management
exemption levels in appendix XI of 40
CFR part 261 and that the waste will be
disposed of in a monofill or land
disposal unit.
The Agency requests comment on
whether these requirements, similar to
§ 261.36 (b)(l),(3) and (4), will provide
adequate information to the
implementing agency and the public on
what exemption levels, i.e., appendix X
to 40 CFR part 261 or appendix XI of 40
CFR part 261, are being claimed and on
how the waste is being managed. These
provisions would be requirements
rather than conditions.
D. Implementation Conditions
As set out in § 261.37 (d) and
explained in the base exemption
implementation preamble (section VIII.
B., Implementation Conditions) certain
conditions have to be met to maintain
the exemption after the claim has
become effective. Under both option 1A
and IB, the following conditions would
have to be met to maintain the
contingent management option:
Submitting changes in notification
information to the Director within 10 ,
days of the change, following the
schedule for retesting, preparing and
complying with a sampling and analysis
plan for every retest, maintaining
constituent concentrations in the
nonwastewater at or below the
exemption levels in appendix XI,
meeting applicable treatment levels
under § 268.40, and maintaining records
on-site for three years. These conditions
are very similar to those proposed for
the base exit in Section VIII of today's
proposed rulemaking. In addition to
those conditions established for the base
exemption, the claimant would also
have to ensure that the waste was
managed in a qualifying unit.
Claimants, under both options, always
"have the obligation to identify whether
they are generating a hazardous waste
and to notify the approprie
government official if they
priate
aey are
generating a hazardous waste. (Section
3010; 40 CFR 261.11.) If any
nonwastewater claimed as exempt
under the contingent management
proposal tested above the exit levels in
appendix XI to 40 CFR part 261 at any
time, that waste and any mixture or
derived-from forms of that waste would
have to be managed as hazardous waste,
including compliance with all
notification requirements, until testing
demonstrated that the waste was below
the exit levels.
1. Tracking Conditions
EPA is proposing to modify the
manifest regulations to reflect the fact
that wastes exiting under this
exemption need not be disposed of in
treatment, storage or disposal facilities
that are subject to the requirements of
§ 264.71-264.72 or Section 265.71-
264.72 requiring the facility that
receives the waste to sign and return the
manifest. EPA is not proposing to
require the owners and operators o'f
nonhazardous waste facilities that
accept wastes exempted under this
option to comply with these duties. As
EPA concluded when it decided not to
extend recordkeeping duties related to
the LDR program to nonhazardous waste
facilities accepting de-characterized
hazardous wastes, it would probably be
difficult to provide reasonable notice to
all the members of this diverse universe,
which has little or no other contact .with
the hazardous waste management
regime, of these Subtitle C
responsibilities.
EPA is proposing instead that the
claimant of the exemption be
responsible for ensuring that the
manifest is returned and that it—or
some other document—provides
information showing that the facility
designated on the manifest did in fact
receive the waste and did place it in a
landfill or monofill (and not a land
treatment unit). Billing documents may
already supply some of the needed
information. Where they do not, EPA
believes that claimants should generally
be able to contract with the receiving
facilities to obtain the necessary
information. In some states,
nonhazardous waste rules may also
require disposers to furnish generators
with some of the necessary information.
EPA proposes to revise the manifest
document as nece.ssary to ensure that
nonhazardous waste facilities can be
designated as receiving facilities for
listed wastes meeting all of the other
requirements for obtaining an
exemption under this option.
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The alternative to this approach
would be to require owners and
operators of nonhazardous waste
facilities to sign and return manifests as
a condition of the exemption. Failure to
satisfy this condition would void the
exemption and return the waste to the
hazardous waste management regime,
ovon if it were in fact safely placed in
an appropriate waste management unit.
EPA requests comment on this
alternative.
Under option 1A, where all Subtitle C
regulations apply until placement of the
nonwastewater in a monofill or landfill,
EPA is proposing conditions that make
the claimant responsible for obtaining a
copy of the manifest to ensure the waste
has reached its destination. The
claimant would also have the burden of
acquiring evidence from the receiving
facility that the waste was placed in
either a monofill or land disposal unit.
Under Option IB, where the
exemption becomes effective upon the
\vaste meeting the appendix XI of 40
CFR part 261 exit levels, any tracking
system established would be a condition
that the claimant would have to meet to
maintain the contingent management
exemption. To ensure that listed wastes
exempted under this option actually go
to a landfill or monofill, EPA is
proposing to require exemption
claimants to comply with the
requirements of part 262 (with the
modification discussed above) relating
to the uniform hazardous waste
manifest.
Since this option allows wastes to go
to facilities that are not subject to the
duty to return the manifest under
§ 264.71-264.72 or § 265.71-264.72,
EPA is proposing to require the claimant
to ensure that the manifest is returned
and that it—or some other document—
provides information showing that the
facility designated on the manifest did
in fact receive the waste and did place
it in a landfill or monofill (and not a
land treatment unit). The duties would
bo identical to those proposed above for
claimants under the first option. The
rationale for imposing the duties on the
claimant—and not the receiving
facility—is also the same.
An alternative which EPA requests
comment on is the concept of imposing
conditions that require a uniform,
national tracking document similar to
the current uniform manifest to
accompany the waste until it reaches its
final destination. This document could
inform transporters and other waste
handlers that the waste is an exempt
hazardous waste that must be managed
in a monofill or land disposal facility
and loses its exemption if it is managed
in a land treatment unit. EPA could
further require that the disposal facility
certify that the nonwastewater was
disposed in a monofill or land disposal
unit and return the tracking document
and certification to the original
exemption claimant. EPA could also
ensure that the implementing agency
(EPA or an authorized state) received
notice of any problems in waste
disposal by imposing requirements
similar to the current § 262.42 exception
reporting provisions.
Another alternative would be to
require, in lieu of a tracking document,
a contractual agreement between the
exemption claimant and the receiving
facility specifying the type of waste the
receiving facility will accept, the type of
units it will use, and information on the
volume and frequency of deliveries.
EPA could require either the claimant or
the receiving facility (or both) to
maintain a copy of the agreement on-site
and make it available to state or EPA
inspectors. EPA also could require
exemption claimants and transporters to
create and keep similar contracts. EPA,
however, requests comment on whether
transporters would require claimants to
provide information on the exempted
waste's origin and the regulatory limits
on its disposal options even without
federal regulation.
EPA requests comment on whether
any of these alternatives can adequately
ensure that mismanagement will not
occur so that these wastes managed
under this option IB approach would
not need to be classified as hazardous.
2. Qualifying Unit
A "qualifying unit" for today's
contingent management proposal is a
landfill or monofill. For purposes of
today's proposal, a landfill is defined in
§ 260.10 as being "a disposal facility or
part of | facility where hazardous waste
is placed in or on land and which is not
a pile, a land treatment facility, a
surface impoundment, an underground
injection well, a salt dome formation, a
salt bed formation, an underground
mine, a cave or a corrective action
management unit." The Agency is
proposing a definition for monofill in
§ 260.10 as a landfill where waste of
only one kind or type is placed in or on
land and which is not a pile, a land
treatment facility, a surface
impoundment, an underground
injection well, a salt dome formation, a
salt bed formation, an underground
mine, a cave, or a corrective action
management unit. Also, for today's
proposal, a land treatment facility is
defined in § 260.10 as being "a facility
or part of a facility at which hazardous
waste is applied onto or incorporated
into the soil surface; such facilities are
disposal facilities if the waste will
remain after closure." The Agency
requests comment on whether other
units could be considered "qualifying
units" for contingent management
exempt waste and whether additional
modeling is needed to assess risks from
management of nonwastewaters from
other units. , , , , ,.
The Agency modeled risks from waste
piles in both its multipathway and
groundwater analyses. It modeled only
groundwater risks form landfills. As
explained elsewhere in this preamble,
EPA believes that the nongroundwater
risks posed by piles generally are higher
than the nongroundwater risks posed by
landfills. EPA, however, is not
proposing to allow wastes placed in
piles to be exempt under the exit levels
for contingent management option 1.
Piles, as defined in Part 260, are
temporary units. To ensure that
exempted wastes removed form piles
went only to landfills or monofills, EPA
would have to impose additional
tracking conditions. These could be
difficult to craft and enforce effectively. .
EPA currently thinks that excluding
piles from eligibility will provide much
better assurance that exempted wastes
will not be mismanaged.
EPA acknowledges that the exit levels
for this option, which are based in many
cases on the evaluation of waste piles,
may, for some pathways, be more
restrictive than levels for landfills. If
EPA later completes a multipathway
analysis of landfill units, it will be able
to use the levels from that modeling in .
lieu of the modeling from piles to derive
exit levels for this option.
The Agency requests comment on the
proposal to exclude wastes placed in
piles from being eligible for exemption
under this option. The Agency also
requests comment on the alternatives of
allowing wastes to be exempt either
permanently or temporarily (e.g., for one
year) after they are placed in piles.
3. Claimant's Duty To Ensure
Compliance With All Requirements and
Conditions
Today's proposal requires that, in
order to claim a contingent management
exemption, the person submitting the
claim must manage the waste for which
the exemption is claimed in accordance
with the requirements and conditions
established by this rule. To satisfy this
rule, the claimant must ensure that the
waste is actually disposed of in a
qualifying unit. The burden of satisfying
all conditions for the exemption falls on
the claimant as the person in the best
position to determine eligibility of a
waste for an exemption and to ensure
informed waste management decisions.
The claimant may enter into contractual
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arrangements with receiving facilities to
allocate responsibility for satisfaction of
the conditions among themselves
although such arrangements will not
relieve the claimant of liability if the
receiving facility manages the waste
improperly. It should be noted,
however, that facilities receiving
contingent management exemption
wastes could also become liable for
violations of permitting, Subtitle C
treatment, storage and disposal
standards should they dispose of the
nonwastewaters that do not qualify.
Under today's proposal, § 261.37(g),
the burden of proof to establish
conformance with the exemption
criteria is on the claimant in the event
of an enforcement action. One
alternative for simplifying the
claimant's burden of proving
compliance with all conditions would
be to set out in the rule certain
documentation that, while not
necessarily required of the claimant,
presumptively would be sufficient
evidence of satisfaction of the
management condition. Of course, EPA
could rebut this presumption regarding
actual disposal through evidence that
the claimant's documentation is
deficient or inaccurate. For example,
claimants might be able to develop
rebuttable evidence of proper off-site
disposal by keeping correspondence
with the receiving facility, indicating
that the waste went to a landfill or
monofill, and by keeping a returned
manifest which indicates that the waste
reached that facility. The Agency is
taking comment on whether establishing
certain evidentiary standards would
provide useful guidance to claimants on
how to satisfy the management
condition and provide helpful incentive
for claimants to maintain proper
documentation of their exemption
claims.
Comment is.also requested on
whether any additional conditions or
requirements, substantive or procedural,
should be imposed on claimants to
ensure that the contingent management
exemption waste is actually managed in
a qualifying unit.
E. Retesting and Recordkeeping
Conditions for Contingent Management
Exemptions
Claimants continuing to generate or
otherwise manage waste for which they
continue to claim a contingent
management exemption would be
required, under § 261.37(d)(2), to retest
the waste with the same frequency and
under the same conditions as is being
proposed for the base exemptions,
§ 261.36(d)(2). If a claimant finds that
the exempted waste no longer meets the
constituent concentration levels on
Appendix XI of 40 CFR part 261 for the
contingent management exemption, or
that the waste has not been placed in a
landfill or monofill, the claimant must
comply with all applicable requirements
for generators of listed wastes (including
disposal of waste at a Subtitle C facility)
and the disposal facility would have to
comply with all of the requirements for
owner/operators of treatment, storage,
and disposal facilities under 40 CFR
parts 262-270. The generator and
disposal facility's obligations would
also include renotifying the Agency of
hazardous waste management activity
using EPA form 8700-12.
Under § 261.37(d)(6), claimants also
would be required to maintain on-site,
for at least three years after Agency
receipt of the notification and
certification, all documentation required
under this rule including, but not
limited to, the sampling and analysis
plan and test data and the
accompanying notification and
certification. These requirements are
similar to those proposed for the "base"
exemption in § 261.36.
The Agency requests comment on
alternative record retention periods for
claimants such as 5 years, which
corresponds to the applicable statute of
limitations period at 28 U.S.C. 2462. An
extended record retention period may
assist claimants in substantiating their
conformance with the contingent
management exemption criteria. The
documentation must be available for
review by the Agency or an authorized
State at the time of site inspection. The
three-year claimant record retention
period will be automatically extended
during the course of any unresolved
enforcement action regarding the
regulated activity.
F. Compliance Monitoring and
Enforcement for Contingent
Management Exemptions
Since contingent management
exemptions are self-implementing, the
Agency needs to rely on its enforcement
authorities to ensure that the
exemptions are being applied in an
appropriate manner and that only those
wastes that are truly nonhazardous are
relieved from Subtitle C disposal
requirements. Compliance monitoring
and enforcement of the contingent
management program would be carried
out under existing authorities and
conditions with which the regulated
community should already be familiar.
Claimants must comply with all of the
previously described conditions of the
exemptions to qualify for the
exemptions. All persons who manage
waste for which an exemption has been
claimed must manage the waste as
required under Subtitle C during
periods when any of those conditions
are not met. Claimants that fail to
comply with the applicable conditions
of the contingent management
exemption risk enforcement action for
violations of Subtitle C requirements,
including administrative, civil and
criminal penalties.
1. Compliance Monitoring
The Agency is proposing that
compliance monitoring of the
contingent management exemption
occur through EPA and State oversight,
primarily through review of
notifications and inspections.
The Agency has the authority, under
section 3007 of RCRA, to require
submission of information and to
conduct inspections of facilities which
EPA has reason to believe may be
generating or managing a hazardous
waste. EPA and States may do
confirmatory sampling and analysis to
determine whether a waste meets the
exemption levels. Under this authority,
the Agency would be able to inspect a
non-Subtitle C facility receiving
contingent management exemption
waste.
Inspections of off-site laboratories
may also be performed.
2. Enforcement
The contingent management
exemption criteria proposed today
would create an exit from the Subtitle
C system only so long as the
requirements and conditions established
for the exemption are met. Failure to
comply with any of the conditions for
the exemption would mean that the
wastes would not be exempt from
Subtitle C, and the claimant could be
subject to immediate enforcement action
for violation of Subtitle C requirements.
The Agency has the authority under
this regulation and RCRA Section 3007
to require submission of information on
the management of exempted wastes in
a situation where the Agency suspects
the claimant has not satisfactorily
determined whether a waste meets the
appropriate exemption levels.
Alternatively, the Agency may require
improved analysis using an
administrative or civil action under
section 3013. Failure to manage the
contingent management exemption
waste in accordance with the conditions
would void the exemption and the
conditionally exempt waste would be
subject to full Subtitle C regulation. The
receiving facility, therefore, would
become a Subtitle C treatment, storage,
and/or disposal facility requiring a
permit.
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In an enforcement action, compliance
with the terms and conditions of the
exemption may be raised as an
affirmative defense, but the burden will
bo on the defendant to establish
eligibility for the exemption and
compliance with the conditions
necessary to maintain the exemption.
See 50 FR 642 (Jan. 4,1985) for a
discussion of EPA's authority to place
such burdens on defendants.
Claimants may not use the contingent
management exemption as a means of
avoiding enforcement actions. For
example, a generator who is the subject
of an Agency enforcement action cannot
claim that the waste in question is
exempted from Subtitle C under the
contingent management exemption
unless a valid exemption notification for
that waste has been previously
submitted to the Agency and the
required documentation to support the
claim exists at the facility and satisfies
the requirements of the regulations. The
contingent management exemption
cannot be used in a retroactive fashion
to avoid enforcement actions. Similarly,
these exemptions cannot be used as a
legal defense prior to the effective date
of promulgation of this rule.
G. Exports of Wastes Eligible for
Contingent Management Exemptions
Under option 1A of today's proposal,
contingent management exemption
wastes would remain hazardous until
actually disposed of in a qualifying unit.
The waste would thus remain subject to
all applicable requirements of 40 CFR
parts 262 and 263, including export
requirements.
Under option IB where the waste
becomes exempt upon meeting the
contingent management exit levels,
comment is requested on whether these
exempt wastes should still remain
subject to the export requirements of 40
CFR part 262. Comment is requested on
xvhether these export requirements are
necessary to ensure that the contingent
management exemption waste will be
properly managed in the receiving
country.
H. Land Disposal Restrictions
As discussed above in section VI, EPA
is proposing two approaches to
integrating LDR requirements with the
exit levels for the base option. First,
EPA is proposing that LDR treatment
requirements will never apply to wastes
that meet exit levels for the base option
at the point of generation. Second, for
wastes which remain subject to LDR
requirements, EPA is proposing to allow
exit levels based solely on the combined
multipathway and groundwater
analyses to serve as alternative risk-
based LDR standards meeting the
"minimize threat" standard in section .
3004(m) of RCRA. EPA believes that
both approaches are appropriate for
contingent management option 1.
To eliminate the duty to comply with
the LDR rules for wastes that meet the
base option exit level at the point of
generation, EPA is taking the position
that such wastes are defined as
hazardous waste pursuant to their
listing descriptions for such a brief
period of time that they effectively
never become subject to Subtitle C
requirements, and LDR requirements
never apply. It is relatively easy to apply
this theory to option IB presented above
in section B.2. that allows
nonwastewaters to exit as soon as they
have met the appropriate concentration
limits and to remain exempt so long as
they are managed in landfills or
monofills. Such wastes need only meet
the exit levels to obtain their exemption.
If they meet them at the point of
generation, they would appear just as
entitled to LDR relief as wastes meeting
the exit levels for the base option.
Under option 1A, however,
nonwastewaters will not exit until they
both meet the exit levels and are placed
in a landfill or monofill. Such wastes
would not be eligible for exit at the
point of generation even if their
constituent concentrations were low
enough. Rather, they would be subject
to Subtitle C regulation for a significant
portion of their "cradle-to-grave"
management cycle. It would be difficult
to argue that these wastes had never
really been regulated as hazardous
wastes, and that LDR treatment
requirements did not apply.
Consequently, EPA is not proposing to
allow nonwastewaters to become
exempt from LDR requirements at the
point of generation under this sub-
option. EPA requests comment on
alternative legal theories that would
provide a better basis for arguing that.
nonwastewaters subject to this sub-
option could be exempt for the LDR
rules if they meet exit levels at the point
of generation.
Both options 1A and IB have
identical exit levels based on removing
the predictions for land treatment units
and using the next-highest
concentration as the exit level. EPA is
proposing to allow the exit levels that
are based solely on the multipathway/
groundwater risk analyses to serve as
minimize threat levels for both options
1A and IB. These levels represent
concentrations posing minimal low
threats for nonwastewater placed in
landfills, monofills and waste piles.
They are based on the same risk
assessment used for the assessment for
the base option. They make the same
"reasonable worst case" assumptions
about the units' physical setting and the
same minimal assumptions about
control measures. Hence, EPA believes
that these exit levels sufficiently reduce
threats to human health and the
environment to meet section 3004(m)'s
"minimize threat" standard.
EPA acknowledges that option IB,
allowing wastes to exit Subtitle C before
they are placed in the right kind of land
disposal unit, presents an additional
type of risk. Under option IB, it maybe
more difficult for EPA to ensure that
exited wastes will not be placed in land
treatment units. (Under the alternative
option, option 1A, Subtitle C manifest
and tracking requirements would
apply.) As explained above in section
B., however, EPA will create conditions
for option IB to help ensure that
exempted wastes are not disposed of in
land treatment units. EPA believes that
these conditions will sufficiently reduce
the risk of inappropriate disposal that
the exit levels will continue to minimize
threats. EPA requests comment on this
aspect of the proposal.
XL Relationship to Other RCRA
Regulatory Programs
Today's rule proposes specific
conditions and exit criteria that would
exempt listed hazardous wastes,
including waste mixtures and derived-
from wastes, from Subtitle C regulation.
Below is a discussion of how this
proposed rule would affect other
relevant RCRA regulatory programs.
A. Hazardous Waste Determination
Under current RCRA regulations, any
person who generates a solid waste
must determine if that waste is a
hazardous waste in accordance with the
procedures outlined in 40 CFR 262.11.
According to 262.11, generators must
first determine if their waste is excluded
from regulation under 40 CFR 261.4.
Generators must then determine if the
waste is listed in subpart D of part 261.
If the waste was not listed, or for
purposes of compliance with 40 CFR
part 268, generators must then
determine if the waste exhibits a
characteristic defined in subpart C of ,
part 261.
Today's proposed rule.is an
exemption for listed wastes meeting the
exit criteria, and does not change the
general requirements for generators
making hazardous waste determinations
under § 262.11 (see discussion of
characteristic waste below).
B. Characteristic Hazardous Waste
Today's proposed rule establishes
exemption criteria for hazardous
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66406 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
constituents in eligible listed wastes,
was^e mixtures, or derived-from wastes.
If the waste satisfies the exemption
criteria proposed today, the waste
would not be considered listed
hazardous waste. However, the
generator must still determine whether
the waste exhibits any characteristics of
a hazardous waste as specified in 40
CFR 261.21 through 261.24 and
continue to meet hazardous waste
requirements if the waste does exhibit a
characteristic.
C. Toxicity Characteristic Level for Lead
Toxicity characteristic constituents
are among those evaluated for exit
values in this proposal. In developing
the risk assessment for all constituents,
including the TC constituents, the
Agency examined risks via groundwater
and other pathways to humans, and also
environmental receptors. In evaluating
risks resulting from the groundwater
pathway, the Agency used its newly
developed CMTP model, and the
MINTEQ metals speciation component.
The CMTP model estimates
groundwater transport using finite
source assumptions, and accounting for
hydrolysis and adsorption of chemicals
to soils. The MINTEQ component
estimates dissolution and speciation of
metals in groundwater. Using these
models, the Agency has developed and
is proposing estimates of transport
through groundwater specific to each
constituent. These estimates are
analogous to constituent-specific
dilution and attenuation factors (DAFs).
These constituent-specific DAFs were
contemplated for several constituents
proposed for regulation in the TC
rulemaking, but not finalized, because
the modeling work was not complete.
TC levels were set using generic DAFs
of 100.
In developing the constituent-specific
DAFs, the Agency estimated that lead
moves through groundwater much more
slowly than predicted by the generic
DAF of 100. While the modeling
analyses supporting the TC rule and
today's proposed rule are somewhat
different from one another, the
constituent-specific DAF for lead
leaching from a landfill was estimated
as 5000 rather than the 100 used in the
TC rule. Higher leaching rates (giving
lower DAF values) were estimated for
some other disposal options evaluated
in the updated modeling, such as land
application and management in surface
impoundments. This analysis raised the
question of how the TC and today's
proposed rules would relate to one
another, and whether these results
warranted consideration of a change to
the TC level of 5 mg/1 for lead (updated
groundwater modeling of other TC
constituents did not show the large
disparity between the TC and exit level
proposed in today's notice for lead).
In considering these issues, the
Agency reviewed several factors. First,
the human health risk evaluation for
lead has changed since the TC rule was
promulgated, resulting in the MCL (on
which the TC is based) for lead being
reduced from 50 ppb to 15 ppb. Using
the new DAF from the landfill scenario
plus the new drinking water standard
could raise the TC level to 75 mg/1 from
the current 5 mg/1. However, when lead
movement from a land treatment
scenario was modeled, a DAF of
approximately 770 resulted, and a TC
level based on this and the new
drinking water standard could be
approximately 10 mg/1. Another
relevant reference point for lead in the
environment includes the current
OSWER soil direct ingestion level for
lead of 400 ppm (as a total
concentration, not leachate).
The Agency considered several
approaches to potentially proposing
revisions to the TC level, including
basing a new TC level on groundwater
modeling only, basing it on the soil
ingestion estimate, or basing it on the
driving pathway value and exit level,
which considers adverse ecologic
effects.
After carefully considering the issue,
the Agency concluded that the issue of
lead toxicity and movement through the
environment is very complex and
changes to existing rules could have
significant impacts on management of
lead-bearing waste and public health.
The agency believes regulation of lead-
bearing wastes warrants careful
consideration and full evaluation of and
review of the policy issues associated
with considering all potential exposure
pathways and risk to human health and
the environment. Questions include
whether the TC level would be a
leachate or totals value, and whether it
would be based on groundwater only or
other exposure routes and whether it
would be human health based or based
on ecological risk considerations. Such
a comprehensive evaluation is not
feasible in the context of the rulemaking
proposed today, and so the agency has
determined to defer any action on the
lead TC level. The Agency recognizes
that this is an issue of considerable
interest to the public, and will consider
review of management of lead-bearing
waste at the soonest practical time. In
the interim, the lead TC regulation and
the exemption regulation proposed
today (when finalized) would co-exist as
independent regulations.
As described in Section IV.E.3, the
Agency has developed groundwater
modeling based on both 10,000 year and
1000 year time frames. Today's proposal
is based on the 10,000 year modeling
time horizon, and the Agency is
soliciting public comment on the
alternative of using 1000 years. One
aspect of the 1000 year modeling results
is that the groundwater-based exit levels
for more constituents would be above
current TC levels for those constituents.
These constituents include, in addition
to lead, chromium, cadmium, selenium,
and mercury. The Agency seeks public
comment on this aspect of using the
1000 year time horizon modeling for
risk assessment in the HWIR rule.
D. Hazardous Waste Listings
The Agency evaluated the likelihood
that untreated hazardous wastes would
be able to meet the exemption criteria in
an "pure" state (e.g., untreated and
unmixed) and determined that it is
unlikely that the constituent
concentrations in many untreated
hazardous wastes would be below
today's proposed exemption levels or
the applicable BOAT standards,
particularly for nonwastewaters.
Specifically, the Agency's hazardous
waste characterization data indicate that
the concentrations of toxicants of
concern in untreated listed wastes are
typically present at levels many times
higher than health-based levels or BOAT
values. Therefore, it is unlikely that the
Agency's current criteria for listing
wastes as hazardous will change as a
result of the introduction of today's exit
criteria into the RCRA regulations.
However, EPA has been utilizing a more
comprehensive risk analysis in the
listing program, looking at multiple
pathways for the movement of
constituents through the environment,
similar to the approach taken in today's
proposal. Today's proposed approach
may also provide the Agency with a
means of assessing whether or not
future listings might inadvertently bring
into the RCRA system the types of low-
concentration wastestreams that would
subsequently be eligible for exit under
today's proposal.
E. Delisting
The evaluation criteria used for
delisting may vary from today's
exemption criteria for various reasons.
First, delisting is an interactive process
that considerable oversight by EPA or
authorized State agencies. In delisting,
the overseeing agency evaluates the
processes generating a specific
wastestream in order to determine the
constituents likely to be present, as well
as the potential variability in the waste.
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EPA (or the State) closely reviews
sampling procedures, analytical test
results, and the accompanying QA/QC
data. This oversight increases the
confidence in the quality and
representativeness of the waste analysis.
Second, delisting is specific to one
wastestream, which decreases
uncertainties that arise in the more
generic approach proposed today. For
example, a delisting petition will
typically provide the annual generation
voiume of the waste. Using a specific
waste volume as an input to various
models has allowed EPA to calculate
exit levels that may be somewhat higher
than the levels proposed in today's rule.
EPA believes that it is reasonable to use
higher exit levels for the smaller waste
volumes in delisting petitions (see 56
FR 32993 (Reynolds Metals) for further
description of volume impact).
The delisting process also allows
more certainty in the plausible
management scenarios that are modeled
to generate exit levels. For example, the
characteristics of the waste may dictate
the likely disposal method (e.g.,
disposal in a landfill of de-watered
process sludge). In some cases, special
management standards may also be a
factor (e.g., radioactive wastes are
regulated under the Atomic Energy Act,
therefore if such a hazardous waste were
delisted, disposal options would be
severely limited (see 60 FR 6054
(Hanford delisting)).
EPA also considers the applicability
of available groundwater monitoring
data from land-based waste management
units that have received the petitioned
waste. Such data are typically required
under permitting regulations for
hazardous waste facilities (see 40 CFR
parts 264 and 265). If any contamination
of groundwater appears to be due to
constituents from the petitioned waste,
EPA will consider this as a basis to deny
the petition. The more generic waste
identification rule proposed today does
not incorporate this additional
evaluation criterion.
EPA may also require special testing
regimes to ensure waste consistently
meets delisting criteria (e.g., see (cite
Reynolds Metals, CSI, Hanford)).
Because the overseeing agency reviews
the petition hi some detail, the testing
frequency may be closely tied to the
potential variability of the waste. A
facility that accepts and treats waste
from diverse sources would typically
have frequent testing requirements (see
40 CFR part 261 appendix IX (Envirite)).
In other cases, the testing requirements
for some initial period will be extensive,
but the subsequent testing may be
reduced.
Delisting petitions for wastes that
contain toxic constituents which exceed
the exemption levels proposed today
will continue to be accepted and
reviewed by the Agency after
promulgation of today's rule. With the
exception of a potentially reduced
petition review burden, the Agency does
not anticipate any changes in the
current review of delisting petitions as
a result of the implementation of today's
proposed exemption. EPA does request
comment on which risk models should
be used to evaluate future delisting
petitions.
F. Requirements for Treatment, Storage,
and Disposal Facilities and Interim
Status Facilities
In order to implement the changes
proposed today, owners or operators, of
RCRA permitted or interim status
facilities may have to amend their waste
analysis plans if required under 40 CFR
264.13 and 265.13. Such changes will
most likely include the addition of the
appropriate analysis methods and
changes that may be required in the
frequency of testing.
Permitted facilities, in unauthorized
States, who elect to employ the
exemption procedures and who
subsequently prepare changes to their
waste analysis plans should, following
promulgation of this rule, submit a Class
I permit modification to EPA. (EPA is
aware that although most States have
either become authorized for, or have
adopted, the 3-class permit modification
regulations, some states may still be
operating under the older "major/
minor" permit modification procedures.
Under those procedures, changes to the
waste analysis plan would be
considered a major modification).
G. Closure
Under today's proposed rule, a
hazardous waste management unit that
receives wastes that are exempt under
today's exit criteria would continue to
be a regulated Subtitle C unit subject to
the requirements of 40 CFR parts 264 or
265, including closure requirements,
until the owner/operator completed
clean closure of the unit or unless all of
the waste in the unit were delisted. A
unit receiving only waste that is exempt
under tciday's proposal would no longer
be receiving hazardous waste upon the
effective date of the exemption; such a
unit would normally become subject to
Subtitle C closure requirements, which
are triggered by the final receipt of
hazardous waste by the unit. The
facility owner or operator is required to
complete closure activities within 180
days after receiving the final volume of
hazardous waste. 40 CFR 264.113(b) and
265.113(b). However, RCRA closure
requirements do allow certain waste
management units to delay closure,
while continuing to receive non-
hazardous waste (such as waste exempt
under today's proposed rule), provided
certain conditions are met.
The RCRA delay-of-closure
regulations, promulgated on August 14,
1989 (54 FR 33376), allow owners or
operators to delay the closure of
landfills, land treatment units, and
surface impoundments in cases where
the unit stops receiving hazardous waste
but the owner or operator wishes to
continue using the unit to manage only
non-hazardous waste. These
requirements are outlined in 40 CFR
264.113(d) and (e) and 265.113(d) and
(e). Owners or operators wishing to
delay closure must request a permit
modification at least 120 days prior to
final receipt of hazardous wastes, or, if
the facility is in interim status, submit
an amended part B application at least
180 days prior to the final receipt of
hazardous wastes. The request for a
permit modification or the amended
part B application must include
demonstrations that the unit has the
existing design capacity to manage non-
hazardous wastes, and that the non-
hazardous wastes are not incompatible
with any wastes in the unit. In addition,
certain facility information including
the waste analysis plan, groundwater
monitoring plans, closure and post-
closure plans, cost estimates, and
financial assurance demonstrations
must be updated as necessary to account
for receipt of only non-hazardous waste.
Sections 264.113(d) and 265.113(d). In
addition, surface impoundments that do
not meet the minimum technological
requirements (MTRs) for liners and
leachate collection of RCRA 3004(o)
must comply with additional
requirements in order to delay closure,
including the removal of hazardous
wastes to the extent practicable from the
unit. Sections 264.113(e) and
265.113(e).
The delay of closure regulations apply
only to landfills, land treatment units,
and surface impoundments. In the case
of other RCRA units such as tanks and
waste piles, the Agency did not feel that
the delay-of-closure regulations were
necessary for these types of units in
order to receive only non-hazardous
wastes (54 FR 33383). The closure
requirements in subpart G for these
units include removal or
decontamination of waste residues,
containers, liners, bases and
contaminated soils, equipment, and
other containment system components;
these closure requirements are not
incompatible with the reuse of these
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units for receipt of only non-hazardous
waste. Once the unit has been emptied
of all hazardous wastes and
decontaminated, it could receive non-
hazardous waste. However, the Agency
also recognizes that some flexibility may
be warranted in converting the use of a
unit such as a tank from hazardous to
non-hazardous waste management. EPA
solicits comment on whether an owner
or operator might demonstrate removal
of hazardous waste residues from the
tank by demonstrating that all waste in
the tank is below exemption levels,
without removing the waste from the
tank. In cases where the owner or
operator could not demonstrate that all
wastes in the tank were below
exemption levels, he or she would have
to remove the hazardous waste in order
to achieve closure of the unit. In some
cases, the facility owner or operator may
be able to demonstrate that a tank no
longer managed hazardous waste
(because the waste met today's proposed
exemption criteria), but did not achieve
clean closure because of soil and
perhaps groundwater contamination. In
this case, EPA solicits comment on
whether the facility owner or operator
should be required to remove the
contamination to clean closure levels, or
close the area as a landfill while using
the tank to manage nonhazardous
wastes, as long as this activity did not
interfere with cleanup activities or
control of the contaminated areas.
The Agency also believes that the
availability of a delay-of-closure option
provides much of the flexibility needed
to allow for the uninterrupted
management of exempt waste, while
providing assurance that the protections
afforded by the closure regulations for
Subtitle C units (e.g., evaluation of soil
and groundwater at closure) are not lost.
This approach makes sense in light of
the fact that today's proposed
exemption is self-implementing, which
the Agency feels is appropriate for waste
identification purposes, but not
necessarily so for determining whether
a Subtitle C unit may become a Subtitle
D unit without first undergoing closure.
H. HWIR-Media Rule/Subtitle C
Corrective Action
The Agency is currently planning on
proposing a rule ("HWIR Media")
addressing waste management issues
relating to environmental media (e.g.,
soil, groundwater, and sediments). The
goal of this rule is to allow more
effective cleanups at contaminated sites.
As currently drafted, the media proposal
will supplement the regulatory system
under RCRA for the management of
RCRA hazardous contaminated media,
applicable to sites that are undergoing
cleanup overseen by EPA or authorized
States. Such sites include cleanups at
RCRA corrective action sites, State
cleanups, and Superfund remedial
actions. The media rule will propose a
"bright-line" distinction between
hazardous contaminated media (i.e.,
media containing hazardous waste that
is therefore regulated as hazardous)
subject to modified Subtitle C standards,
and less contaminated media subject to
more site-specific, flexible standards
implemented by State agencies. This
new system will supplement the current
approach(es) to identifying RCRA
applicability to the management of
contaminated media. The rule will also
propose streamlined permit
requirements for cleanups. It will not
specify cleanup standards.
Today's proposal applies to listed
hazardous wastes (e.g. process wastes,
sludges, discarded commercial chemical
products, etc.), including mixtures of
one or more listed wastes with other
solid wastes, and residues derived from
the treatment, storage, or disposal of one
of more listed hazardous wastes. Media
that contain listed hazardous wastes,
mixtures, or derived-from wastes with
constituent concentrations below
today's proposed exemption levels will
be eligible for exemption under the
procedures proposed today. EPA or an
authorized State may continue to assess
contaminated media with
concentrations higher or lower than the
exit levels proposed today on a case-by-
case basis by making site-specific
determinations as to whether a media
"contains" a RCRA hazardous waste.
/. Land Disposal Restriction Program
Today's rule contains several
important areas of overlap with the
RCRA Land Disposal Restrictions (LDR)
program that are discussed elsewhere in
today's rule. First, as described in more
detail elsewhere in this notice, EPA is
proposing that exit levels produced
under the multipathway analysis for
constituents with adequate analytical
methods should "cap" existing
technology-based LDR standards, where
the exit levels are less stringent than the
current LDR values. If a waste contains
only constituent with "capped" LDR
values, it should be able to satisfy. LDR
requirements and exit Subtitle C for all
other purposes as soon as the waste
achieved those levels.
Under today's proposal the uncapped
LDR requirements for listed hazardous
wastes continue to apply to a waste
even after the waste becomes exempt
from Subtitle C under the exemption
criteria. Furthermore, for listed wastes
containing certain constituents with
analytical problems, compliance with
the LDRs (either numerical levels,
specified treatment, or both) is part of '
the criteria for exempting that waste
under today's proposal. Specifically, for
constituents where there are no
adequate analytical methods for
determining whether or not the exit
levels have been met, a combination of
meeting applicable LDR standards and a
showing of non-detect estimated
quantitation concentration is required to
satisfy the exit criteria for these
constituents. This is explained in more
detail in Section IV.I of today's rule.
If, however, a listed waste is below
the exit concentrations proposed today
at the point where the waste is "first"
generated, that is, the point where the
waste first meets the listing description
and is potentially subject to Subtitle C,
then a hazardous waste is never really
"generated" and the LDR requirements
do not attach to the waste. The EPA
does not expect many listed wastes to be
at or below the exit criteria at the point
of first generation, where waste
characterization data indicate that this
is where wastes contain higher
concentrations of hazardous
constituents. Nonetheless, where a
particular process generates a waste that
is perhaps inappropriately captured by
a listing, or where pollution prevention
efforts by the generator result in a waste
of lower constituent concentrations, if
the waste meets the exemption criteria
at the moment it is first generated, the
LDR requirements would not apply. In
contrast, once a listed waste is generated
and managed the LDR requirements
attach, and remain even after the waste
exits Subtitle C under today's
exemption (unless, as stated, where the
exit levels are considered equivalent to
a minimize threat standard). This issue
is discussed in more detail in Section VI
in today's proposal.
It should be noted that the Agency is
currently reviewing the definition of
"point-of-generation" with respect to
the application of the LDRs. Since
November 1986 (51 FR 40620), EPA has
required LDR determinations to be made
at the point which hazardous wastes are
generated. In the Phase III LDR rule
(March 2,.1995, 60 FR 11702), EPA
solicited comment on the issue of where
the point of generation should be
defined. EPA presented three options to
narrowly redefine the point at which the
land disposal prohibitions attach: (1)
Similar wastestreams generated by
similar processes, (2) wastestreams from
a single process, and (3) "battery
limits." With Option 1 the point of
generation would be defined at the
point after which like wastestreams are
generated from like processes and
combined as a matter of routine
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66409
practice. Option 2 would consider the
point of generation to occur when
wastestreams from a single process are
combined (e.g., residual wastestreams
collected in a common unit such as a
sump). In many cases, these
wastestreams are similar in composition
because they all come from a common
unit process. The Option 3 "battery
limits," is similar to Option 2; however
instead of limiting aggregation to that
normally occurring within a single unit
process, the facility would view an
entire battery of processes (associated
with making a single product or related
group of products) as a single
manufacturing step. In the Phase ffl LDR
proposal, EPA identified listed
hazardous wastes as situations where
existing point of generation
determinations may remain appropriate.
This is because EPA has carefully
reviewed the various waste streams and
has defined the point of generation as
part of the listing description. Therefore,
it may be inappropriate to modify that
description with a more generic "point
of prohibition" rule. This is important
because today's rule applies only to
listed hazardous wastes.
Lastly, under today's proposal,
mixtures containing listed hazardous
waste and residues from the treatment,
storage, or disposal of listed hazardous
waste that contain some constituents
with concentrations below exit levels
and some constituents with
concentrations above exit levels would
continue to be managed as listed
hazardous wastes. Today's notice does
not allow for partial exemptions,
because the Agency does not believe
that a self-implemented exemption
process is well suited to partial
exemptions. It is not always clear what
tho origin of a hazardous constituent is,
particularly for constituents that are
formed as by-products of treatment or
waste interactions. Further, the
proposed exemption criteria are not
waste-specific, and thus are not suited
to waste-specific or partial exemptions.
Thus, the determination that a waste
that carries two listing numbers should
no longer bear one of the listing
numbers is not always a straight-
forward decision. The Agency has
designed the exemption process
proposed today to remove as much
subjective decision making from the
process as possible.
However, while the Agency is not
today proposing an alternative that
would allow these wastes to use only
the hazardous waste codes for those
listed wastes that are the origin of the
constituents above the exit levels, the
Agency believes that there could be
merit in the concept for a future
proposed rulemaking should the
implementation concerns stated above
be overcome. Therefore, the Agency
requests information on actual cases
with waste characterization data where
a waste bears more than one waste code
which results in conflicting treatment
standards under the land disposal
restrictions rules. If the Agency finds
that there is a serious compliance issue
for multiple listing wastes, the Agency
may reconsider this decision, as well as
other potential solutions to any
documented problems.
/. RCRA Air Emission Standards
Today's proposed rule, when
promulgated, may have an impact on
the effectiveness of two other RCRA
rules developed by the Agency under
HSWA authority. Section 3004(n) of
HSWA directed the Agency to
promulgate regulations controlling air
emissions from hazardous waste TSDFs
"as necessary to protect human health
and the environment." Subsequent
Agency analysis demonstrated that air
emissions from TSDFs do pose
substantial risk in the absence of
controls, and that controls were
therefore required under the HSWA
mandate. The Agency is fulfilling this
mandate in phases; EPA completed the
first phase when it promulgated RCRA
air standards that control organic
emissions vented from certain
hazardous waste treatment processes, as
well as from leaks in certain ancillary
equipment used for hazardous waste
management processes (55 FR 25454,
June 21,1990; 40 CFR part 264/265,
subparts AA and BB). More recently,
EPA completed the second phase when
it promulgated RCRA air standards for
tanks, surface impoundments,
containers, and miscellaneous units
operated at TSDFs (59 FR 62896,
December 6,1994; 40 CFR part 264/265,
subpart CC). Together, these rules
would reduce the risk from air
emissions from the vast majority of
these facilities to well within the risk
range of other RCRA standards. After
more thorough analysis, the Agency
may issue a third phase of these
regulations to address any residual risk.
The emission reductions achieved by
these rules would also significantly
reduce the formation of ozone, which
has adverse effects on human health and
the environment.
Hazardous waste that satisfies the
exemption criteria proposed today
(including any constituent-specific exit
concentrations for volatile organic
chemicals, or VOCs), would be exempt
from Subtitle C regulations, including
regulations promulgated to date under
RCRA 3004(n). In other words, once a
waste is no longer regulated as
hazardous, any unit in which the waste
is managed (assuming no other
hazardous wastes are being/have been
managed in the unit) is not subject to
Subtitle C regulations, including 40 CFR
parts 264 and 265, subparts AA, BB, and
CC. However, the Agency believes that
it is important to ensure that the risks
associated with air emissions both from
hazardous wastes, and from wastes that
would be eligible for exit under today's
proposal, are adequately addressed. In
the final rule establishing air emission
controls for tanks, surface
impoundments, containers, and
miscellaneous units (the "Subpart CC"
rule), the Agency established a
threshold level of 100 ppmw (parts per
million by weight) for total volatile
organics in a waste, a concentration
which if equaled or exceeded that
would trigger the emission control
requirements for these units. Because
there are examples of exit levels
proposed today for specific volatile
organic constituents that exceed this
100 ppmw threshold, the Agency
considered whether today's exit levels
adequately addressed the air emission
concerns of 3004(n) in allowing,waste to
exit Subtitle C. There are important
differences in the underlying risk
modeling between the two rules.
However, the Agency believes that the
constituent-specific risk evaluation
done for this rulemaking results in
proposed exit levels that for VOCs will
not be less protective than the standards
established to date under RCRA 3004(n).
Despite these differences, the Agency
requests comment on whether or not a
total VOC concentration of 100 ppmw
(parts per million weight), which is the
concentration that triggers air emission
controls under the Subpart CC rule,
would be appropriate for use in the exit
rule proposed today, and if so, how this
level would be used.
K. Hazardous Debris
Hazardous debris that contains one or
more listed hazardous wastes is eligible
for exiting Subtitle C under today's
proposed rule. The EPA notes, however,
that certain exemptions already exist
relating to hazardous debris. On August
18,1992, the EPA published a final rule
on the Land Disposal Restrictions for
Newly Listed Wastes and Hazardous
Debris (57 FR 37194). In that rule, EPA
required that hazardous debris be
treated prior to land disposal, using
specified treatment technologies from
the treatment categories of extraction,
destruction, or immobilization. (See 40
CFR 268.45, Table 1.) EPA also added a
conditional exemption at § 261.3(f) for
non-characteristic hazardous debris (i.e.,
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debris that is hazardous solely because
it contains one or more listed hazardous
wastes). Section 261.3(f)(l) exempts
debris from Subtitle C regulation
provided that the debris is treated using
one of the extraction or destruction
technologies specified in Table 1 of
§ 268.45. Alternatively, non-
characteristic hazardous debris can be
exempt under § 261.3(f)(2) if it is
determined to be no longer hazardous
by the Regional Administrator, after
considering the extent of contamination
of the debris, i.e., after a "contained-in"
determination is made. However, non-
characteristic hazardous debris
contaminated with a listed waste, that is
treated by a specified immobilization
technology is not eligible for the
conditional exemption in § 261.3(f)(l),
and therefore remains subject to Subtitle
C regulation after treatment.
In today's rule, EPA is not proposing
to change the current exemption under
§ 261.3(f); therefore, non-characteristic
hazardous debris that requires LDR
treatment by extraction or destruction
technologies will be exempt from
Subtitle C regulation, once treated. As
was explained more thoroughly in the
final rule for hazardous debris, the
Agency gave careful consideration to
many factors before exempting certain
treated debris, including whether each
debris/contaminant type would be
effectively treated by each BDAT
technology to levels that would no
longer jose a hazard to human health or
the environment (57 FR 37240).
However, hazardous debris that
contains listed waste, and for which
immobilization is the specified LDR
treatment, may exit using today's
proposed exit criteria. See also the
discussion of a contingent management
option above for a description of an
alternative for encapsulated debris
contaminated by radioactive;"mixed"
hazardous wastes. Finally, EPA is not
proposing to change the contained-in
exemption under § 261.3(0(2) for
hazardous debris; that is, the Regional
Administrator may continue to
determine on a case-by-case basis that
hazardous debris no longer contains
listed hazardous waste, and should
therefore be exempt from RCRA Subtitle
c-'
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Were EPA to proceed on this course,
the Agency would adjust the timing of
any regulatory action so that it does not
supersede the separate rulemaking the
Agency is now conducting on certain
uses of residues derived from K 061
recovery facilities. 59 FR 67256. Thus,
the Agency does not intend to take final
action affecting these uses until the
analysis begun in that rulemaking is
completed on the schedule established
in that rulemaking.
With respect to the other pending
proposal, involving a prohibition on
placement of hazardous waste as fill
material, the Agency requests comment
on whether it should substitute
permission to use waste that has met the
proposed exit levels for the proposed
prohibition. The risk assessment
underlying today's proposal addressed
the major pathways that would arise
from use as fill, but may not have used
input values that fully reflect the fill
scenario for some important parameters.
For example, unit depths may be greater
for fill sites than for land application
units. At the same time, use of
hazardous waste as fill is a proven cause
of human health and environmental
harm, contributing significantly to a
number of Superfund sites. See Docket
F-95-PH3P-FFFFF (record for the
pending proposal). In light of this, the
. Agency questions whether to substitute
today's proposed exit approach for the
proposed prohibition.
XII. CERCLA Impacts
All listed hazardous wastes are listed
as hazardous substances under section
101(14)(C) of the Comprehensive
Environmental Response,
Compensation, and Liability Act
(CERCLA) of 1980, as amended. Under
section 103(a) of CERCLA, notification
must be made to the Federal
government of a release of any CERCLA
hazardous substance in an amount equal
to or greater than the reportable quantity
(RQ) assigned to that substance within
a 24 hour period. (See 40 CFR part 302
for a list of CERCLA hazardous
substances and their Rqs.) If a specific
waste from a particular facility meets
the exemption criterion in this rule, the
waste is not a listed hazardous waste
and therefore not a hazardous substance
by virtue of its hazardous waste listing.
Thus, notification under CERCLA of a
release of the exempted waste may not
be necessary. In this situation, CERCLA
notification of releases of the waste
would only be required if the waste or
any of the constituents of the waste are
CERCLA hazardous substances by virtue
of Section 101(14) (A), (B), (D), (E), or
(F) of CERCLA or 40 CFR 302.4(b), and
are released in amounts greater than or
equal to then- Rqs. The Agency requests
comment on this approach.
Exit levels also may be applicable to
the CERCLA program where it has been
documented that RCRA listed hazardous
waste has been disposed of at the site.
Section 121(d) of CERCLA, as amended
by the Superfund Amendments and
Reauthorization Act (SARA) of 1986,
requires that CERCLA actions comply
with, or justify a waiver of, applicable
or relevant and appropriate
requirements (ARARs) under federal
and state environmental laws. The
options proposed in this rule would
determine the legal applicability of
federal RCRA managements
requirements to remediation wastes
generated at Superfund sites. They may
also be considered in determining
whether RCRA is relevant and
appropriate in cases where it is not
applicable.
At sites undergoing CERCLA remedial
activities where no listed hazardous
wastes have been identified, the Agency
will generally use a site-specific risk
assessment for all chemicals for which
there are no ARARs. In some cases,
these health-based cleanup levels will
be higher than the exemption levels,
based on a reasonably conservative
exposure scenario which does not
include leachate ingestion. In other
cases, the CERCLA health-based clean-
up levels will be lower than exemption
levels when additive effects are
considered or when specialized
analytical techniques are required in
order to lower quantitation limits. The
CERCLA health-based clean-up levels
may also be different than exemption
levels based on the consideration of site-
specific factors.
XHI. State Authority
A. Applicability of Rules in Authorized
States
Under section 3006 of RCRA, EPA
may authorize qualified States to
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 the Hazardous and Solid
Waste Amendments (HSWA) of 1984, a
State with final authorization
administered its hazardous waste
program entirely in lieu of EPA
administering the Federal program in
that State. The Federal requirements no:
longer applied in the authorized State
and EPA could not issue permits for any
facility in the State that the State was
authorized to permit. When new, more
stringent Federal requirements were
promulgated or enacted, the State was
obliged 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 the HSWA take effect in authorized
States at the same time that they take
effect in non-authorized States. EPA is
directed to implement HSWA
requirements and prohibitions in an
authorized State, 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, HSWA applies in
authorized States in the interim.
B. Effect of State Authorizations
Today's proposal, if finalized, will
promulgate regulations that are not
effective under HSWA in authorized
States. Thus, the exemption will be
applicable only in those States that do
not have final authorization.
Authorized States are only required to
modify their programs when EPA
promulgates Federal regulations that are
more stringent or broader in scope than
the authorized State regulations. For
those changes that are less stringent or
reduce the scope of the Federal
program, States are not required to
modify their programs. This is a result
of section 3009 of RCRA, which allows
States to impose more stringent
regulations than the Federal program.
Today's proposal for exit levels is
considered to be less stringent than, or
a reduction in the scope of, the existing
Federal regulations because it would
exempt certain wastes now subject to
RCRA Subtitle C. Therefore, authorized
States are not required to modify their
programs to adopt regulations consistent
with and equivalent to today's proposal.
Even though States are not required to
adopt most options in today's proposal,
EPA strongly encourages States to do so
as quickly as possible. As already
explained in this preamble, today's
proposal will reduce over-regulation of
dilute wastes and will provide an
alternative to delisting. States are
therefore urged to consider the adoption
of today's proposal (when promulgated);
EPA will expedite review of authorized
State program revision applications.
C. Streamlining Issues
EPA is considering a new approach to
state authorization for rules revising the
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RCRA program. Under this new
approach EPA would vary the •,
requirements for state submissions and:
for EPA's review to reflect differences in
the scope and complexity of various
program revisions. This differential
approach to authorization also would
recognize the fact that many states now
have more than a decade of experience
in implementing large portions of the
RCRA program and commensurate
experience in obtaining authorization
for program revisions. EPA believes that
adjusting authorization requirements
will strike an appropriate balance
between recognizing state experience
and ensuring environmental protection.
EPA recently proposed a greatly
streamlined set of procedures for the
least complex changes to the LDR
program in the "LDR Phase IV"
rulemaking; EPA, however, proposed to
retain the current authorization process
for other portions of the rule that
presented more complex and novel
regulations.
EPA is also developing a different
approach to streamlining authorization
for the "HWIR media" proposal
scheduled for publication later in 1995.
Although EPA expects some aspects of
these state authorization procedures to
be unique to the HWIR- media
rulemaking, EPA will determine
whether some of the concepts can be
used to craft streamlined procedures for
additional RCRA rules.
EPA was not able to develop a :..
streamlined authorization process for
this rule in time to include it in this .--
proposal. EPA, however, intends to ..(• .
describe such a process in more detail
in the preamble to the proposed HWIR-
media rule. EPA anticipates that mostc
elements of the basic waste exit scheme
proposed in today's notice would be
eligible for a greatly streamlined .
approach to authorization. For example,
the new LDR standards based on
"minimize threat" findings would be
good candidates for streamlined
authorization because states that are
already .authorized for significant
portions of the LDR program are familiar
with the type of rule changes needed,
have adopted all or most of the
underlying LDR program, and have
experience in implementing and
enforcing the rules. The exit levels,
along with the self-implementing
approach to exit determinations,, are :
alsp likely to be eligible for a greatly
streamlined approach. The scheme is
very similar to the existing program for
determining whether a waste exhibits
any of the hazardous waste
characteristics, particularly the 1980 EP
Toxicity Characteristic and the ' ?
expanded 1990 Toxicity Characteristic.
Under both the characteristic rules and
today's proposal, generators are
responsible for determining whether or
not a waste meets a numerical definition
of "hazard". States must then enforce by
reviewing records of determinations
and/or conducting their own analysis of
wastes determined not to be hazardous.
Consequently, States which have been
authorized for the base program already
have experience in adopting and
enforcing rules which resemble the exit
scheme proposed today. EPA, however,
notes that adopting the exit scheme
proposed in today's notice will place
additional demands on state inspection
and enforcement resources. EPA will
give careful consideration to balancing
the need to ensure that a state has
sufficient resources to implement an
exit program with the goal of
streamlining the authorization process.
Today's scheme does differ from the
original characteristics and the 1990
Toxicity Characteristic by including
some requirements which must be
enforced as conditions of exit. These
requirements, however, are
requirements for testing, notification
and recordkeeping that are relatively
easy to meet and relatively easy to
detect if violated. Accordingly, EPA
does not at this time anticipate that
these conditions would require it to
retain the current authorization process.
EPA currently Jinds it unlikely that it
will propose a greatly streamlined
authorization process for any of the
contingent management options
presented for discussion in today's
proposal. These options,will raise novel
legal, implementation and enforcement
issues. A more conventional approach
to the review of state authorities and
capabilities may be warranted. If EPA
proposes any of these options in the
future, it will consider the possibility .of
adapting the approach to authorization
that it is currently developing for the
HWIR-media proposal.
XIV. Regulatory Requirements
A. Analytical Requirements
1. Executive Order 12 S66 '. -.
Under Executive Order 12866, (58 FR
51735 (October 4,1993);) the Agency
must determine whether this regulatory
action is "significant." A determination
of significance will subject this action to
full OMB review and compliance tinder
Executive Order 12866 requirements.
The order defines "significant
regulatory action" as one that is likely
to result in a rule that may: ; '.
(a) Have an annual effect on' the
economy of $100 million or more,
adversely affect in a material" way the':
economy, a sector of the'economy,:
productivity, competition, jobs, the
environment, public health or safety, or
state, local, or tribal governments or
communities;
(b) Create a serious inconsistency or
otherwise interfere with an action taken
or planned by another agency;
(c) Materially alter the budgetary
impact of entitlement, grants, user fees,
or loan programs, or the rights and
obligations of recipients thereof; or
(d) Raise novel legal or policy issues
arising out of legal mandates, the
President's priorities, or the principles
set forth in the terms of the Executive
Order.
The proposed rule is expected to have
an annual effect on the economy greater
than $100 million. Furthermore,
although voluntary, the adoption of this
action may burden state or tribal
governments with increased regulatory
review requirements. Today's action
may also raise novel legal or policy
issues as they relate to the President's
priorities for environmental protection
within a regulatory system facing
resource limitations. The Agency,
therefore, has determined that today's
proposed rules is a "significant
regulatory action." As a result, this
rulemaking action, and supporting
analyses, are subject to full OMB review
under the requirements of the Executive
Order. The Agency has prepared an
Assessment of The Potential Costs and
Benefits of The Hazardous Waste
Identification Rule for Industrial Process
Wastes, as Proposed, in support of
today's action. A summary of this
Assessment and findings is presented in
section D below.
2. Regulatory Flexibility Analysis
Pursuant to the Regulatory Flexibility
Act of 1980, 5 U.S.C. 601 et seq., when
an agency publishes a notice of
rulemaking, for a rule that'will have a •
significant effect on a substantial
number of small entities, the agency
must prepare and make available for
public comment a regulatory flexibility
analysis. This analysis shall consider
the effect of the rule on small entities •
(i.e.: Small business, small
organizations, and small governmental
jurisdictions).
Under the Agency's revised
Guidelines'for Implementing the
Regulatory Flexibility Act, dated May 4,
1992, the Agency committed to •
considering regulatory alternatives in
rulemakings .when there were any
economic impacts estimated on any
small entities. Previous guidance
required alternatives to be examined
only when significant economic effects
were estimated fora substantial number
of small entities. The Agency has • '
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prepared a Regulatory Flexibility
Analysis in support of today's action. A
summary of this analysis and findings is
presented in section E below.
3. Environmental Justice
Executive Order 12898, "Federal
Actions to Address Environmental
Justice in Minority Populations and
Low-Income Populations," directs each
Federal Agency to "make achieving
environmental justice part of its mission
by identifying and addressing, as
appropriate, disproportionately high
and adverse human health and
environmental effects of its programs,
policies, and activities on minority
populations and low-income
populations * * *"
The Executive Order requires that
where environmental justice concerns
or the potential for concerns are
identified, appropriate analysis of the
issue(s) be evaluated. To the extent
practicable, the ecological, human
health (taking into account subsistence
patterns and sensitive populations) and
socio-economic impacts of the proposed
decision-document in minority and low-
income communities should also be
evaluated.
The Agency has examined
Environmental Justice concerns relevant
to today's action. A summary of this
analysis and findings is presented in
section F below.
4. Paperwork Reduction Act
The information collection
requirements in this proposed rule have
been submitted for approval to the
Office of Management and Budget
(OMB) under the Papenvork Reduction
Act, 44 U.S.C. 3501 et seq. An
Information Collection Request (ICR)
document has been prepared by EPA
(ICR No. 1766.01) and a copy may be
obtained from Sandy Farmer, OPPE
Regulatory Information Division; U.S.
Environmental Protection Agency
(2137); 401M St., SW.; Washington, DC
20460 or by calling (202) 260-2740.
This information collection is
required to provide documentation of
solid waste exemptions from Subtitle C
requirements, and will allow for
certification and verification as the
program evolves. Exemptions under
today's action require no formal
preapproval. As such, information
collection, maintenance and reporting
issues are especially important due to
the self-implementing nature of this
action. Successful implementation of
today's proposal will depend upon the
documentation, certification, and
verification provided by the information
collection.
The general authority for this
proposal is sections 2002(a), 3001, 3002,
3004, and 3006 of the Solid Waste
Disposal Act of 1970, as amended by the
Resource Conservation and Recovery
Act of 1976 (RCRA), as amended by the
Hazardous and Solid Waste
Amendments of 1984 (HSWA), 42
U.S.C. 6912(a), 6921, 6922, 6924, and
6926. The specific authority for the
collection of information is 40 CFR
261.36, Exemption for Listed Hazardous
Wastes Containing Low Concentrations
of Hazardous Constituents.
The Agency has prepared a full
Information Collection request (ICR) in
support of today's action. A summary of
the methodology and findings from this
document is presented in section G
below.
B. Background
In 1976, Congress passed the Resource
Conservation and Recovery Act (RCRA)
to address problems associated with
annual nationwide generation of large
quantities of municipal and industrial
solid waste. This Act was significantly
amended in 1984 by the Hazardous and
Solid Waste Amendments (HSWA).
Under RCRA, the Agency regulates non-
hazardous solid waste through the
Subtitle D program, and hazardous solid
waste under the Subtitle C program.
Subtitle C regulations differ from
Subtitle D in two important areas. First,
Subtitle C regulations are developed and
promulgated by EPA, while Subtitle D
requirements have been largely
delegated to the states. Second, non-
hazardous wastes regulated under
Subtitle D are generally subject to
standards that are considerably less
stringent and less costly than those
under Subtitle C. All wastes addressed
under this action are currently managed
under Subtitle C regulations.
RCRA is divided into four programs:
Underground storage, medical waste,
nonhazardous solid waste, and
hazardous solid waste. Under RCRA
3001(a), Congress has required EPA to
identify those Wastes that should be
classified as hazardous. In accordance
with this provision, the Agency has
designated wastes as hazardous in two
ways: "characteristic," or "listed."
Hazardous waste is considered
characteristic if it has any of the
properties or characteristics that would
present a potential hazard if managed
improperly. The Agency has identified
four characteristics which, if exhibited,
lead to hazardous classification. These
are: Ignitability, corrosivity, reactivity,
and toxicity. Under the toxicity
characteristic, specific health-based
concentration standards have been
developed for approximately forty (40)
constituents. Wastes exhibiting any of
these characteristics are subject to
Subtitle C regulation. Hazardous wastes
are identified as listed based on an
extensive listing procedure. This
procedure may identify a waste as
hazardous under three broad categories:
if it exhibits one of the characteristics
identified above but has not been
classified as characteristically
hazardous, if it is determined to be
acutely toxic or hazardous, or if the
waste meets the statutory definition of
a hazardous waste.
The Agency, however, was concerned
that generators and managers of
hazardous waste might avoid regulatory
requirements in two major ways: (1) By
mixing listed hazardous waste with
non-hazardous solid waste, and, (2) by
minimal processing and treatment of
hazardous waste. These activities could
result in a waste or residual material
that was no longer legally defined as
hazardous under Subtitle C. In many
cases, the Agency believed these
materials could continue to pose
unacceptable hazards to human health
and the environment. The Agency
promulgated mixture and derived-from
rules in May of 1980, in response to
these potential loopholes.
C. Need for Regulation
The mixture and derived-from rules
created what was perceived as being
federal over-regulation, where listed
hazardous waste continued to remain
under Subtitle C jurisdiction regardless
of constituent concentration or presence
in the waste, either before or after
treatment. This problem was
exacerbated with the passage of HSWA
in 1984. HSWA set Land Disposal
Restrictions (LDR) requiring best
demonstrated available technology
(BDAT) treatment for all listed
hazardous wastes prior to disposal. In
cases where a specific listed
wastestream contained relatively ;
innocuous constituents, or very low
concentrations, BDAT treatment
requirements were felt to be overly
protective, and unnecessarily expensive.
By requiring Subtitle C management
for some low risk wastes, the current'
RCRA regulatory system may inhibit the
efficient allocation of limited societal(
resources. From a social perspective^ too
. many resources devoted to managing
low risk wastes may reduce resource
availability for managing higher risk*
wastes. Resource availability for general
productivity investments and
innovative technologies are also . ?' .
reduced. The Agency's delisting
program has not provided an efficient
solution to this problem. The delisting
process has proven to be overly time
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66414 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
and resource intensive for both industry
and EPA.
The Agency believes that a simpler
exemption process is necessary to
reduce the over-regulation of low risk
hazardous waste while, at the same
time, reducing the time and resource
burden on industry and government.
This revised exemption process would
• also reduce the burden on the delisting
program which will continue under
current regulations. To meet these goals,
the Agency is proposing the current
action that would establish a single set
of exit levels for constituents found in
listed hazardous waste. This action
would cover wastes as-generated,
derived-from wastes, including BDAT
treatment residuals, mixtures with solid
wastes, and environmental media that
contain hazardous wastes.
D. Assessment of Potential Costs and
Benefits
1. Introduction and Summary
The U.S. Environmental Protection
Agency (EPA) has prepared an
Assessment of The Potential Costs and
Benefits (Assessment) to accompany
today's proposed rulemaking action.
This action will establish concentration-
based exemption criteria for certain
hazardous wastes, creating a mechanism
to exclude from Subtitle C regulation
those listed industrial process wastes
that the Agency believes are clearly not
of Federal regulatory concern. Today's
proposed rule addresses low hazard
wastes, mixtures, treatment residuals,
and media that contain hazardous
wastes.
The Agency anticipates that the
proposed rule will provide cost savings
to selected generators and managers of
low hazard wastes. Under the preferred
option, annual nationwide treatment
and disposal cost savings for exempted
wastes may be as high as $75 million.
Annual cost savings for a single facility
may be as high as $5.03 million.
Potential cost reductions beyond
treatment and disposal savings may be
associated with waste minimization
incentives, avoided treatment costs for
wastes remaining within Subtitle C, and
administrative cost savings.
Exemption of eligible wastes from
Subtitle C management requirements is
projected to have negligible effects on
human health and the environment. The
proposed exemption levels are based on
detailed analysis of numerous possible
routes of exposure. These exemption
levels are designed to be protective of
both human health and ecological
systems when exempted wastes are
managed under Subtitle D, including
state regulated waste disposal systems.
The Agency has also evaluated other
impacts of the proposed rule. These
include: Environmental justice,
unfunded mandates, regulatory takings,
and waste minimization incentives.
Environmental justice concerns
associated with today's proposed action
may be in the form of economic benefits
and/or human health effects. Today's
proposal implements no enforceable
requirements on.states. Federal
unfunded mandates, therefore, are not
relevant to today's proposed
rulemaking. Regulatory takings under
today's proposed rulemaking will not
approach land or productive value
impacts discussed in past House aiid
Senate Bills presented on this issue.
This rulemaking provides opportunities
for generators to implement waste
minimization.procedures to gain
additional savings.
The complete document, Assessment
of The Potential Costs and Benefits of
The Hazardous Waste Identification
Rule for Industrial Process Wastes, as
Proposed (Assessment), is available in
the docket established for this proposed
rule. This document details the data,
methodology, findings, regulatory
issues, and analytical limitations
associated this Assessment. The rapid
evolution of this action resulted in
continuous technical modifications
throughout the development of this
proposal. An Addendum to the
Assessment document that details final
quantity and cost savings estimates is
included in the docket materials.
Findings presented in this preamble
present final estimates.
A summary of the Assessment
methodology and findings is presented
below. The analysis conducted for this
Notice of Proposed Rulemaking is to be
considered preliminary. The Agency
welcomes review and comment of this
document and urges the submission of
data in support of any comment or
response.
2. Regulatory Options
The Agency's Assessment, conducted
in support of today's action, addresses
the costs, benefits, and other potential
impacts of the preferred option. The
Assessment also examines various other
regulatory options based on exit levels
that are both more and less stringent.
Findings presented in this preamble •
discuss the preferred option and one
primary alternative. A full discussion of
findings associated with various
alternative regulatory options is
presented in the Assessment and
Addendum.
a. Preferred (Proposed) Option
Under the preferred option, exit
criteria are established for
approximately 400 constituents,
allowing hazardous wastes (including
waste mixed with or derived-from listed
wastes) to exit Subtitle C if the
concentration of all constituents is less
than or equal to the exemption criteria.
The exit levels apply to all listed wastes,
regardless of origin.
Exit levels for most constituents are
based on risks posed to human health
and the environment. The Agency's goal
is to ensure, through Federal or State
management requirements, that humans
are not exposed to carcinogens in
concentrations that will increase the
statistical risk of cancer by more that
one-in-one-million (1 x 10-6). For non-
carcinogens, the Agency's goal is to
ensure that humans are not exposed to
concentrations where the hazard
quotient exceeds one (1). The Agency
feels that, above this level, selected
populations may experience
carcinogenic effects at a 10-* risk level
and non-carcinogenic effects at a hazard
quotient greater than one (1).
To determine the concentrations at
which exempt wastes would not pose
human health risks in excess of these
target levels, EPA conducted a
"Multipathway" Analysis that included
ecological exposure pathways. In
addition, EPA considered the effects of
direct exposure to contaminants in
groundwater. The analyses consider
several types of waste management
units. For non-wastewaters these unit
types include landfills, land application
units, waste piles, and ash monofills. •
For wastewaters management units
included tanks and surface
impoundments.
. The concentrations from all other
pathways were compared to the '. . •
groundwater concentrations in
determining the exit level. The more
stringent of the multipathway or
groundwater numbers was chosen as the
exit level. Exit levels for some ,
constituents are'based on surrogates, or
Exemption Quantitation Criteria (EQCs).
MCLs were not used in the development
of exit levels analyzed for this option.
The Agency believes that levels
established under this process will
ensure protection of human health and
the environment. These exit levels are
presented in the regulatory language for
this proposed rulemaking.
b. Other Options
In developing the preferred option,
the Agency compared the proposed rule
to several alternative regulatory options.
These are discussed in the full
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document, Assessment of The Potential
Costs and Benefits of The Hazardous
Waste Identification Rule for Industrial
Process Wastes, as Proposed. Additional
options are discussed in the supporting
Addendum to the Assessment
document. These options consider
alternative waste management
requirements, target risk levels, dilution
and attenuation factors (DAFs), and
exposure pathways. This Preamble
discusses one primary alternative to the
preferred option. This alternative is the
same as the preferred option but drops
land application units from
consideration as a management source.
Exempt nonwastewater wastestreams
could not he land applied. There would
bo no change for wastewaters.
3. Implementation Requirements
Implementation requirements include
the steps that generators (or waste
managers) must take to achieve
exemption of their wastes, regardless of
the exit levels selected. These
requirements include waste sampling
and analysis, and related recordkeeping
and reporting. Under the proposed rule,
the facility must first perform a
comprehensive analysis of the waste,
testing for all constituents identified in
appendix X to 40 CFR part 261.
Reduced initial testing may be possible
only if a facility is able to document that
such constituents are not present in the
waste. The generator must then prepare
a notificatioErfcertification package and
submit it to the EPA Regional
Administrator or authorized state
agency. The generator must repeat a
comprehensive analysis periodically
according to the schedule established in
the proposed rule, along with more
frequent tailored scans that focus on the
constituents of concern. Related
documentation must be maintained on-
sito and be available for review.
The Agency has estimated annual
sampling, analysis, recordkeeping, and
reporting costs (collectively referred to
as "implementation costs") that may be
required under this rule. These
estimates range from approximately
521,000 for a less complex, solvent
wastestream with testing every 12
months, to $169,000 for a complex high
quantity F039 wastestream with testing
every three months.
4. Analysis and Findings
Under the proposed rule, listed
wastes from industrial processes may be
eligible for exemption from Subtitle C
hazardous waste requirements if they
contain low concentrations of
contaminants. This exemption may
allow generators and waste managers to
avoid some or all costs associated with
Subtitle C requirements. The most
significant cost savings relate to waste
treatment and disposal; this rule will
allow generators to avoid the costs of
treatment required for compliance with
the Land Disposal Restrictions as well
as the costs of disposing wastes in
highly protective Subtitle C facilities.
In addition to assessing these cost
savings, the Assessment addresses a
number of other potential effects of the
regulations. It analyzes the relative
effects of the regulatory options on
human health and the environment and
considers issues related to ensuring
environmental justice, eliminating
federal mandates, encouraging waste
minimization, and providing flexibility
for small businesses.
a. Eligible Waste
The universe of annual listed waste
generation, both wastewaters and
nonwastewaters, potentially affected by
today's proposed rulemaking is
estimated to total 303.6 million tons.
The universe of potentially affected
wastes includes approximately 25,300
wastestreams from 10,700 facilities.
Wastewaters account for the vast
majority of total waste quantity (99
percent).
To determine whether these wastes
are likely to be eligible for exemption,
EPA developed the Process Waste
Model. This model uses data on the
characteristics of individual listed
waste-streams first collected in 1986 for
EPA's National Survey of Hazardous
Waste Generators, which has since been
updated, refined, and in some cases,
corrected. The model first compares the
reported concentrations of constituents
in each wastestream to the proposed
rule exit levels to determine whether the
waste is likely to be eligible for
exemption without further treatment. If
the waste is not eligible as-reported, the
model then considers whether it may be
eligible after treatment. In this
comparison, the concentration
standards established under EPA's Land
Disposal Restrictions (which are based
on the use of the best demonstrated and
available technology) are used as a
proxy for the lowest concentrations
achievable by treatment. If the waste is
not eligible for exemption as-reported or
after treatment, EPA assesses whether
waste minimization or pollution
prevention methods could be used to
cost-effectively achieve the exit levels.
This model does not address
contaminated media.
The analysis indicates that:
• Under the preferred option, total
nonwastewater quantity exempted,
including BOAT treatment residuals and
sludge from wastewater, is estimated at
0.40 million tons. Total wastewater
(liquid) quantity exempted is
approximately 64 million tons.
• Under the primary alternative
option (no land application),
approximately 65 million tons of
wastewaters, and 0.60 million tons of
nonwastewaters, including BOAT
treatment residuals and sludge from
wastewaters, may be eligible for
exemption.
b. Cost Savings
The proposed rule will allow waste
generators and managers to avoid costs
associated with Subtitle C requirements.
Specifically, this exemption will allow
them to avoid treatment costs and/or
costs of disposing wastes in Subtitle C
facilities. Wastes which meet exit levels
at the point of generation may accrue
treatment cost savings because the
wastes will not require any treatment
that would have been needed to comply
with the Subtitle C Land Disposal
Restrictions prior to disposal. All
exempt wastes are likely to accrue
disposal cost savings because the costs
of disposing wastes in non-Subtitle C
facilities are generally lower than the
cost of more protective Subtitle C
facilities.
The analysis indicates that:
• Under the preferred option, the
high-end estimate of annual treatment
and disposal cost savings is
approximately $75 million.
—A large portion of these savings are
attributable to avoided treatment
costs.
• Under the primary alternative, the
high-end estimate of cost savings is $99
million.
The above estimates for quantities
exempted and cost savings assume zero
implementation costs. The
incorporation of implementation costs
into the analytical model will have a
significant impact on facilities and ,
wastestreams affected, while having
only a marginal impact on total
quantities exempted.
c. Affected Wastestreams and Facilities
Under the preferred option ' • -:
(unconditional exemption), as high as
41 percent (10,300) of the potentially
affected wastestreams may be eligible
for exemption. These eligible '
wastestreams are generated by 56
percent (6000) of the facilities ' ••'-''•'
producing listed waste. Total ;
wastestreams and facilities potentially
eligible for exemption .under the
primary alternative option (no land ••
application) are estimated at 12,200 (48
percent), and 7,000 (65 percent); :
respectively. - "--
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66416 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
The majority of the wastestreams
eligible for exemption under the
preferred option are very small in
quantity. The median annual generation
size of an eligible wastewater
wastestream is 20 tons. The median for
eligible nonwastewaters is 2.6 tons. For
small wastestreams, the costs accrued
due to the exemption are likely to be
counterbalanced by the costs associated
with gaining the exemption.
While a relatively large number of
wastestreams and facilities meet the
eligibility criteria for exemption, many
may not gain exemption because the
costs of exemption may outweigh the
estimated cost savings from exemption.
For example, if implementation costs
average $35,000 annually per
wastestream, the estimate of facilities
generating an exempted wastestream
may be overstated by as much as 90
percent. However, small generators may
choose to aggregate their wastes to avoid
this problem.
d. Relative Impacts on Human Health
and the Environment
Today's proposed rule will allow low
concentration hazardous wastes to exit
RCRA Subtitle C regulation and be
disposed of in Subtitle D nonhazardous
waste units. The Agency believes that
today's proposed rule will have little
effect on human health for the following
reasons:
• The acceptable daily exposure
levels used to set the exit levels are
based on maximum risk levels for
carcinogens of 10-6 and on acceptable
daily doses for non-carcinogens at
which no adverse effects are likely to
occur.
• The waste management units
modeled in the Multipathway Analysis
provide high potential release rates for
the various groups of constituents being
considered in the analysis based on
their physical and chemical properties.
• The pathways included in the
Multipathway Analysis are generally
considered to be the most critical.
• The Multipathway Analysis
includes populations that are likely to
be exposed more than the average adult
duejtp proximity to a contaminant
source, behavior patterns, activities, and
body size.
• High-end values were used for
selected parameters in the Multipathway
Analysis to calculate acceptable waste
concentrations.
• Exit levels represent acceptable
constituent concentration levels for ,
Subtitle D waste management based on
all of the potential combinations of ..
management units, and receptors in .the
Multipathway Analysis.
• Exit levels for several constituents
are below the acceptable waste
concentrations for human health due to
the inclusion of ecological receptors.
Ecological risks were also evaluated
for selected key constituents. The
inclusion of such risk in solid waste
regulation at a national level is an
important step, and is preferable to
establishing exit criteria based only on
human health risks.
5. Other Regulatory Issues
a. Environmental Justice
Economic benefits may occur to
selected communities as affected local
facilities reinvest cost savings derived
from reduced treatment and/or disposal
costs. Human health effects are expected
to be negligible due to the stringency of
the exit levels. Included in these exit
levels are pathways of particular
concern for selected low income
populations such as subsistence fishing
and farming.
b. Other Issues
Today's proposal is expected to have
no impact in the area of Unfunded
Federal Mandates or Regulatory
Takings. Waste minimization
procedures are likely to be stimulated
under this proposal.
6. Implications and Conclusions
The analysis indicates that
approximately 11 percent of the
quantity of all nonwastewaters
containing listed codes, and 21 percent
of all such wastewaters may be eligible
for exemption under the proposed rule.
This exempt quantity is dominated by a
small number of very large
wastestreams, and includes a large
number of very small wastestreams. For
some small wastestreams, exemption
may not be cost effective unless
generators aggregate their wastes or
otherwise work cooperatively to
minimize the costs of gaining the
exemptions.
Today's proposal could also provide
incentives for industry to implement
process changes and increased recycling
in an effort to gain additional savings.
Preliminary estimates indicate that
savings from these activities, when
combined with treatment and disposal
savings from the preferred option, are
likely to result in total annual cost
savings greater than $100 million.
However, limitations of our analysis
suggest that the cost savings estimates
from such activities are highly
uncertain. Additional savings .related to
administrative requirements and
reduced treatment for hazardous wastes
may, also accrue. These potential
additional cost savings are -discussed in
greater detail in the Assessment
document. ......
The Agency believes that today's
proposal will result in a net benefit to
society. Wastes gaining exemption
under the preferred option will not pose
unacceptable incremental risks to
human health and the environment
because the exit levels are based on
extensive analysis of possible human
and ecological risks associated with
exempt wastes.
EPA's analysis of the impact of
today's proposal on industry groups
indicates that a limited number of
industries are likely to benefit from
exemption. Under the preferred option
(unconditional exemption), three
industries account for 51 percent of .
eligible nonwastewater and wastewater
sludge quantity and 53 percent of total
treatment and disposal cost savings.
These industries are: Chemicals and
allied products (SIC 28); fabricated
metals (SIC 34); and primary metals (SIC
33).
The Agency also compared benefits
gained from exemption to key industry
data such as national pollution
abatement expenditures and considered
facility level impacts of the proposal. To
evaluate the relative magnitude of cost
savings that would accrue under the
proposed rule, EPA compared cost
savings estimates to total pollution
abatement expenditures and the total
value of industry shipments. Total
treatment and disposal cost savings
under the preferred option account for
approximately 3.5 percent of annual
operating costs for hazardous waste
pollution abatement activities, and less
than 0.002 percent of the total value of
industry shipments. The facility-level
impacts of the proposal vary greatly.
E. Regulatory Flexibility Analysis.
The Regulatory Flexibility Act
requires analysis of the impact of
regulations on small entities. Because
today's proposal is deregulatory, it is
not expected to have adverse impacts on
small businesses. In general, generators'
of large quantity wastestreams posing
low hazards will benefit substantially
from the regulations. The impacts on
small quantity generators is less certain
and depends on the degree to which
they aggregate their wastes and work
cooperatively to cost-effectively gain
exemption.
F. Environmental Justice
It is the Agency's policy that
environmental justice be considered as
an integral part in the development of
all policies, guidance and regulations.
Further, Executive Order '12898,
"Federal Actions to Address
-------
Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66417
Environmental Justice in Minority
Populations and Low-Income
Populations", directs each Federal
Agency to "make achieving
environmental justice part of its mission
by identifying and addressing, as
appropriate, disproportionately high
and adverse human health and
environmental effects of its programs,
policies, and activities on minority
populations and low-income
populations * * * "
The Executive Order requires that
where environmental justice concerns
or the potential for concerns are
identified, appropriate analysis of the
issuc(s) be evaluated. To the extent
practicable, the ecological, human
health (taking into account subsistence
patterns and sensitive populations) and
socio-economic impacts of the proposed
decision-document in minority and low-
income communities should also be
evaluated. Examples include how a
policy on future land use would impact
minority or low-income communities
versus non-minority, affluent
communities, or how subsistence
farming or fishing patterns relate to risk-
assessment policies.
For the purposes of today's proposed
rulcmakmg, the Agency has taken an
approach for proposal consistent with
Executive Order 12898. As currently
drafted, the multipathway analysis
which was used to develop the exit
levels takes into account subsistence
farmers and subsistence fishers;
however, subsistence fishers were
evaluated using a recreational fisher
database (one does not exist for
subsistence fishers). Sensitive
populations are accounted for in the
RfDs, RfCs, and slope factors and
ecological receptors were also
evaluated.
G, Papenvork Reduction Act
As stated earlier, the level of
implementation costs (i.e. sampling,
analysis, recordkeeping, and reporting)
will have a significant impact on the
number of wastestreams and facilities
affected by this proposal. Assuming
annual implementation costs of $35,000
per wastestream, as many as 269
facilities, generating up to 285 different
wastestreams may seek exemptions, and
therefore be affected by the
recordkeeping and reporting
requirements. The actual number of
facilities and wastestreams affected will
depend upon the level of
implementation costs. The higher the
implementation cost to the facility, the
fewer the number of facilities expected
to participate in the HWIR program.
The estimated hour burden ranges
from 382 hours to 573 hours per
wastestream in the first year, and from
31 hours to 146 hours per wastestream
in years two and three. The variation in
burden estimates results from different
assumptions in (1) the complexity of the
waste (and therefore of the test methods
required), and (2) the frequency of
reporting. The estimated total hour
burden over the first three years ranges
from 206,900 to 293,465 hours,
averaging 68,967 to 97,821 hours per
year.
The estimated total start-up cost of
recordkeeping and reporting in the first
year ranges from $55,000 to $235,000
per wastestream. The annual cost in the
second and third years is estimated to
be $9,000 to $209,000 per wastestream
(of which $8,000 to $203,000 is the cost
of shipping samples to a laboratory and
paying to have them tested). In years
four and five the high-end cost drops to
$53,000. The estimated annual
recordkeeping and reporting cost per
wastestream, annualized at seven
percent over five years,' is $21,000 to
$170,000. The total recordkeeping and
reporting cost burden over the first three
years is $28,000,000 to $32,000,000.
Burden means the total time, effort, or
financial resources expended by persons
to generate, maintain, retain, or disclose
or provide information to or for a
Federal agency. This includes the time
needed to review instructions; develop,
acquire, install, and utilize technology
and systems for the purposes of
collecting, validating, and verifying
information, processing and
maintaining information, and disclosing
and providing information; adjust the
existing ways to comply with any
previously applicable instructions and
requirements; train personnel to be able
to respond to a collection of
information; search data sources;
complete and review the collection of
information; and transmit or otherwise
disclose the information.
An Agency may not conduct or
sponsor, and a person Is not required to
respond to a collection of information
unless it displays a currently valid OMB
control number. The OMB control
numbers for EPA's regulations are listed
in 40 CFR part 9 and 48 CFR chapter 15.
Comments are requested on the
Agency's need for this information, the
accuracy of the provided burden
estimates, and any suggested methods
for minimizing respondent burden,
including through the use of automated
collection techniques. Send comments
on the ICR to the Director, OPPE
Regulatory Information Division; U.S.
Environmental Protection Agency
(2137); 401 M St., SW.; Washington, DC
20460; and to the Office of Information
and Regulatory Affairs, Office of
Management and Budget, 725 17th St.,
NW., Washington, DC 20503, marked
"Attention: Desk Officer for EPA."
Include the ICR number in any
correspondence. Since OMB is required
to make a decision concerning the ICR
between 30 and 60,days after December
21,1995, a comment to OMB is best
assured of having its full effect if OMB
receives it by January 22,1996. The
final rule will respond to any OMB or
public comments on the information
collection requirements contained in
this proposal.
List of Subjects in 40 CFR 261 and 268
Identification and listing of hazardous
waste. Land disposal restrictions.
Dated: November 13,1995.
Carol Browner,
Administrator.
XV. References
U.S. Environmental Protection Agency,
Environmental Monitoring Systems
Laboratory; "Performance Testing of
Method 1312—QA Support for RCRA
Testing." EPA/600/4-89/022, June 1989.
Research Triangle Institute; "Interlaboratory
Comparison of Methods 1310,1311, and
1312 for Lead in Soil". U.S. EPA Contract
• 68-01-7075, November 1988.
U.S. Environmental Protection Agency,
Office of Solid Waste and Emergency
Response; OSWER Directive No. 9285.7;
"Human Health Evaluation Manual, Part B:
Development of Risk-based Preliminary
Remediation Goals;" from Henry Longest
II, Director, Office of Emergency and
Remedial Response; and Bruce Diamond,
Director, Office of Waste Programs
Enforcement; to Regional Waste
Management Division Directors; December
13,1991.
U.S. Environmental Protection Agency,
Office of Solid Waste and Emergency
Response; OSWER Directive No. 9850.4;
"Interim Final Guidance for Soil Ingestion
Rates;" from J. Winston Porter, OSWER
Assistant Administrator; to Regional
Administrators (I-X); January 27,1989.
U.S. Environmental Protection Agency,
Office of Research and Development,
' Office of Health and Environmental
Assessment; "Exposure Factors
Handbook;" EPA/600/8-89/043, March
1990.
U.S. Environmental Protection Agency,
Office of Solid Waste: EPA's Composite
Model for Leachate Migration with
Transformation Products (EPACMTP),
Background Document, 1995a.
U.S. Environmental Protection Agency,
Office of Solid Waste: EPA's Composite
Model for Leachate Migration with
Transformation Products (EPACMTP),
User's Guide, 1995b.
U.S. Environmental Protection Agency,
Office of Solid Waste: Finite Source
Methodology for Non-Degrading and
Degrading Chemicals with Transformation
Products, 1995c.
U.S. Environmental Protection Agency,
Office of Solid Waste: Background
-------
66418 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
Document for EPACMTP: Fate and
Transport Modeling of Metals, 1995d.
U.S. Environmental Protection Agency,
Office of Research Development. Finite
Source Methodology for Wastes Containing
Metals, 1992.
U.S. Environmental Protection Agency,
Office of Research Development
MINTEQA2/PRODEFA2, A Geochemical
Assessment Model for Environmental
Systems: Version 3.0 User's Manual. EPA/
600/3-91/021, March 1991.
U.S. Environmental Protection Agency,
Office of Research Development.
Environmental Fate Constants for
Chemicals Under Consideration for EPA's
Hazardous Waste Identification Projects,
compiled by Heinz Kollig, 1993.
Appendix A
TABLE A-1 .—HUMAN EXPOSURE PATHWAYS
Exposure medium
Groundwater
Air
Air
Soil
Soil
Soil
Soil
Soil
Soil
Plant (veg/root)
Plant (veg)
Plant (veg/root) .. .
Plant (veg/root)
Animal (beef/milk)
Animal (beef/milk)
Animal (beef/milk)
Animal (bedf/milk)
G roundwater
Surface water
Route of exposure
Ingestion
Inhalation
Inhalation
Ingestion
Ingestion
Ingestion
Dermal
Dermal
Dermal
Ingestion
Ingestion
Ingestion
Ingestion
Ingestion
Ingestion
Ingestion
Ingestion
Dermal (bathing)
Ingestion
Type of fate and
transport
Groundwater
Direct air
Direct air
Direct soil
Overland
Air deposition
Direct soil
Overland
Air deposition
Air deposition
Air diffusion
Direct soil
Overland
Air deposition
Air diffusion
Direct soil
Overland
Groundwater
Air diffusion
Pathway a
1
WMU — groundwater — * humans
Ingestion of contaminated groundwater as a drinking water source.
2a (on site or off site)
WMU — •• air .— •• humans
Inhalation of volatiles
2b (on site or off site)
WMU — * air — * humans
Inhalation of suspended particulates
3 (on site)
WMU — humans
Ingestion of contaminated soil
3 (off site)
WMU — - overland — * humans
Ingestion of contaminated soil
4
WMU — - air — • deposition to soil — - humans
Ingestion of contaminated soil
5 (on site)
WMU — >• humans
Dermal contact with contaminated soil ,
5 (off site)
WMU — * overland — * humans
Dermal contact with contaminated soil
6
WMU — * air — * deposition to surface soil — humans
Dermal contact with contaminated soil
8
WMU — • air — * deposition to soil/gard crops — * garen crops — > humans
Consumption of contaminated crops grown in home gardens
8a
WMU — * air — * garden crops — • humans
Consumption of contaminated crops grown in home gardens
9 (on site)
WMU — • garden crops — » humans
Consumption of contaminated crops grown in home gardens
9 (off site)
WMU — > overland — * garden crops — - humans
Consumption of contaminated crops grown in home gardens
10
WMU — * air — * deposition to soil/feed crops — * cattle — * humans
Consumption of animal products with elevated levels of toxicant caused
eating contaminated feed crops and soil
10a
WMU . — air — * feed crops — • cattle — • humans
Consumption of animal products with elevated levels of toxicant caused
eating contaminated feed crops
11 (on site)
WMU — feed crops — •• cattle — * humans
Consumption of animal products with elevated levels of toxicant caused
eating contaminated feed crops and soil
11 (off site)
WMU —* overland — feed crops/soil — cattle — * humans
Consumption of animal products with elevated levels of toxicant caused
eating contaminated feed crops and soil
14
WMU — * .groundwater — •• humans
Ingestion of contaminated surface water as a drinking water source
17
WMU — ' groundwater — *• humans
Dermal bathing contact with contaminated groundwater
by
by
by
by
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Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66419
TABLE A-1.—HUMAN EXPOSURE PATHWAYS—Continued
Exposure medium
Surf£tc@ water
Surface water
Fish
Fish
Fish
Animal (beef/milk) ..
Animal (beef/milk) ..
Animal (beef/milk) .
Surfaco water
Surface water
Surface water
Route of exposure
Ingestion
Ingestion
Ingestion
Ingestion
Ingestion
Ingestion
Ingestion
Ingestion
Dermal (bathing)
Dermal (bathing) ....
Dermal (bathing)
Type of fate and
transport
Overland
Air deposition
Air diffusion
Overland
Air deposition
Air diffusion
Overland
Air deposition .. . .
Air diffusion
Air deposition
Overland
• Pathway a
\
19
WMU — * overland flow — ' surface water — • humans
Ingestion of contaminated surface water as a drinking water source
20
WMU — > air — - deposition to soil — - overland flow — - surface water — > hu-
mans
Ingestion of contaminated surface water as a drinking water source
21
WMU — - air — > surface water — • fish — - humans
Consumption f fish contaminated by toxicants in surface water
23
WMU — overland — * surface water — - fish — * humans
Consumption f fish contaminated by toxicants in surface water
24
WMU — ' air — deposition to surface soil — * overland flow — > surface water
— fish — > humans
Consumption f fish contaminated by toxicants in surface water
33
WMU — air — - suface water — * cattle — * humans
Consumption of animal products with elevated levels of toxicant caused by
drinking contaminated surface water
35
WMU —>overland flwo — • surface water — * cattle — ' humans
Consumption of animal products with elevated levels of toxicant caused by
drinking contaminated surface water
36
WMU — * air — * deposition to soil — * overland flow — > surface water — > cattle
— *• humans
Consumption of animal products with elevated levels of toxicant caused by
drinking contaminated surface water
37
WMU — * air -» surface water — humans
Dermal bathing contact with contaminated surface water
38
WMU — * air deposition to soil — * overland flow — * surface water — • humans
Dermal bathing contact with contaminated surface water
42
WMU — overland flow — surface water — > humans
Dermal bathing contact with contaminated surface water
Overland » Soil erosion; Overland flow = Both runoff and sold erosion; or, for surface impoundments, a spill directly to surface water. Veg •
Aboveground fruits and vegetables. Root - Belowground (or root) vegetables.
"Some pathway numbers are missing, reflecting pathways that have been eliminated from the analysis or combined with other pathways.
TABLE A-2.—ECOLOGICAL EXPOSURE PATHWAYS
Terrl
Terr II
Exposure medium
Soil
Soil
Plant
Soil fauna
Animals
Soil
Route of exposure
Ingestion
Direct contact
Ingestion
Ingestion
Ingestion
Ingestion
Type of fate and
transport
Direct soil
Direct soil
Direct soil
Direct soil
Direct soil
Overland
Pathways3
3 (on site)
WMU — mammals, birds, soil fauna
Ingestion of contaminated soil
5 (on site)
WMU — > plants, soil fauna
Direct contact with contaminated soil
9 (on site) ; ,
WMU — * vegetation — <• mammals, birds
Consumption of contaminated vegetation (e.g., forage
grasses)
11a (on site)
WMU — * soil fauna — mammals, birds •
Consumption of soil fauna (e.g., earthworms, insects) with
elevated levels of toxicant
1 1 b (on site)
WMU — * soil _fauna/vegetation — animals — * predatory mam-
mals, birds'
Consumption of animals with elevated levels of toxicant
3 (off site)
WMU — - overland — mammals, birds, soil fauna
Ingestion of contaminated soil ?•<*'
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66420 Federal Register /Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
TABLE A-2.—ECOLOGICAL EXPOSURE PATHWAYS—Continued
Terr III
Terr IV
Terr V . .
Aq 1
Aq II
Aq III
Exposure medium
Soil
Plant
Soil fauna
Animals
Soil
Soil ....
Plant
Plant
Surface water .. . .
Fish
Surface water
Surface water
Fish
Surface water
Surface water
Fish
Surface water
Route of exposure
Direct contact
Ingestion
Ingestion
Ingestion
Ingestion
Direct contact
Ingestion
Ingestion
Ingestion
Ingestion
Direct contact
Ingestion
Ingestion
Direct contact
Ingestion
Ingestion
Direct contact
Type of fate and
transport
Overland
Overland
Overland
Overland
Air deposition
Air deposition
Air deposition
Air diffusion
Air diffusion
Air diffusion
Air diffusion
Air deposition
Air deposition
Air deposition
Overland
Overland
Overland ...
Pathways3
5 (off site)
WMU — overland — • plants, soil fauna
Direct contact with contaminated soil
9 (off site)
WMU — * overland — vegetation — > mammals, birds
Consumption of contaminated vegetation (e.g., forage
grasses)
11c (off site)
WMU — > overland — > soil fauna — - mammals, birds
Consumption of soil fauna (e.g., earthworms, insects) with
elevated levels of toxicant
11d (off site)
WMU -— soil fauna/vegetation — • animals — - predatory mam-
mals, birds
Consumption of animals with elevated levels of toxicant
4
WMU — - air — •• deposition to soil — » mammals, birds, soil
fauna
Ingestion of contaminated soil
6
WMU — air — * deposition to surface soil — > plants, soil fauna
Direct contact with contaminated soil
8
WMU — * air — •• deposition to soil — * vegetation — <• mammals,
birds
Consumption of contaminated vegetation (e.g., forage
grasses)
8
WMU — * air — • vegetation — - mammals, birds
Consumption of contaminated vegetation (e.g., forage
grasses)
17
WMU — * air — ' surface water — * mammals, birds
Ingestion of contaminated surface water as a drinking water
source
21
WMU — - air — * surface water — * fish — •• mammals, birds, fish
Consumption of fish contaminated by toxicants in surface
water
37
WMU — * air — ' surface water — •• fish, daphnids, benthos
Direct contact with contaminated surface water, sediments
37
WMU — * air — > deposition to soil — <• overland flow — * surface
water — * mammals, birds
Ingestion of contaminated surface water as a drinking water
source
24
WMU — - air — * deposition to surface soil — * overland flow — *
surface water — fish — •• mammals, birds, fish
Consumption of fish contaminated by toxicants in surface
water
38
WMU '-* air — •• deposition to soil — * overland flow — • surface
water — • fish, daphnids, benthos
Direct contact with contaminated surface water, sediments
19
WMU — * overland flow — * surface water — mammals, birds
Ingestion of contaminated surface water as a drinking water
source
23
WMU — overland flow — * surface water — • fish — • mammals,
. birds, fish
Consumption of fish contaminated by toxicants in surface
water
42
WMU — * overland flow — *' surface water — - fish, daphnids,
benthos
Direct contact with contaminated surface water, sediments
Overland=Soil erosion. Overland flow=Both runoff and soil erosion; or, for surface impoundments, a spill directly to surface water.
-------
Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66421
•Some pathway numbers are missing, reflecting pathways that have been eliminated from the analysis.
TABLE A-3.—SUMMARY OF HUMAN RECEPTORS FOR EXPOSURES PATHWAYS
Pathway
<17* Air HiffttQfnn /QW^-rtermal fhathtnal
42: Overland (SW)-dermal (bathing)
Adult
Va
Va
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
V
Child
Va
v
v
Va
v
v
v
v
v
V
Subs.
farmer
V
v
Va
v
v
v
Va
v
v
v
v
Receptor
Home
gardener
V
V
Va
V
Subs.
fisher
V
V
V
v
Fish
consumer
V
V
V
Worker
V
V
V
•On-site pathways for receptors other than workers are modeled only for the land application unit after closure.
TABLE A-4.—SUMMARY OF ECOLOGICAL RECEPTORS BY EXPOSURE PATHWAYS
Pathway
91 • Air ffiffii«5inn-fi<;h inflection
37* Air diffusion (SW)-direct contact
38* Air deposition (OF/SW)*direct contact .
40: Grnundwater fSWl-direct contact
Mammals
Va
v
V
v
V
v
v
v
v
v
v
v
v
v
v
v
v
v
v
Birds
Va
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
Plants
V
v
v
Receptor
Soil
fauna
v
v
v
V
v
V •
Fish
V
v
v
v
V
V
V
Daphnids
V
V
V
Benthos
V
V
V
-------
66422 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
TABLE A-4. — SUMMARY OF ECOLOGICAL RECEPTORS BY EXPOSURE PATHWAYS— Continued
Pathway
42: Overland (SW)-direct contact
Receptor •
Mammals
Birds
Plants
Soil
fauna
Fish
V
Daphnids
V
Benthos
V
aOn-site pathways are modeled only for the land application unit after closure.
TABLE A-5.—PATHWAYS MODELED FOR EACH WASTE MANAGEMENT UNIT
Pathway
1: Groundwater-ingestion
2a: Direct air-inhalation volatiles
2b: Direct air-inhalation particles
3: Direct soil-soil ingestion
4: Air deposition-soil ingestion , .
5: Direct soil-dermal (soil)
6: Air deposition-dermal (soil)
8: Air deposition-veg/root ingestion
8a: Air diffusion-veg/root ingestion
9: Direct soil or overland-veg/root ingestion
10: Air deposition-beef/milk ingestion
10a: Air diffusion-beef/milk ingestion
1 1 : Direct soil or overland-beef/milk ingestion
14: Groundwater-dermal (bathing)
17: Air diffusion-drinking water ingestion .
19: Overland-drinking water ingestion
20: Air deposition-drinking water ingestion
21: Air diffusion-fish ingestion
23: Overland-fish ingestion
24: Air deposition-fish ingestion
33: Air diffusion (SW)-beef/milk ingestion
35: Overland (SW)-beef/milk ingestion
36: Air deposition (OF/SW)-beef/milk ingestion
37: Air diffusion (SW)-dermal (bathing)
38: Air deposition (OF/SW)-dermal (bathing)
42: Overland (SW)-dermal (bathing)
Waste management unit
Ash
monofill
V
V
V
V
V
v .
V
V
V
Land
appl. unit
v-
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
Wastepile
V
V
V
V
V -
V
V
V
V
V
V
V
V
V
V
V
V
V ,
V
V
V
V
V
V
V
Surface
impound.
V
V
V
V
V
V
V
^
V
V
V
V
Tank
.V
V
. V
V
V
V
V
Water
use
V
OF=Overland flow. SW=Surface water.
Appendix B
-------
TABLE B-1.—COMPARISON OF GROUNDWATER MODELING RESULTS FOR 1000 vs. 10,000 YEARS TIME HORIZON (HQ=1 AND RisK=lo-6)
[Threshold Chemical Concentrations for 1000 and 10,000 years Grotmdwater Modeling]
No.
1
2
3
4
5
6
7
8
9
10
176
177
178
12
13
14
15
16
17
11
179
18
19
20
21
22
23
24
25
180
26
27
28
29
30
31
32
33
34
35
36
181
182
37
183
38
39
40
41
42
CAS No.
83329
67641
75058
98862
107028
79061
107131
309002
107051
62533
7440360
7440382
7440393
71432
92875
50328
205992
100516
100447
56553
7440417
111444
4E+07
117817
75274
74839
71363
85687
88857
7440439
75150
56235
57749
126998
106478
108907
510156
124481
67663
74873
95578
16065381
7440473
218019
7440508
108394
95487
106445
98828
72548
Name of Chemical
Acenaphlhene « „
Acetone (2-propanone)
Acetonitrile (methyl cyanide)
Acetophenone
Acrolein
Acrylamide #
Acrylonitrile # " . .
Aldrin # ...
Allyl Chloride
Aniline #
Antimony
Arsenic # . .
Barium
Benzene #
Benzidine #
BenzoFalpyrene #
Benzo[b]fluoranthene #
Benzyl alcohol
Benzyl chloride #
Benz[a]anthracene #
Beryllium #
Bis(2-chloroethyl)ether #
Bis(2-chloroisopropyl)ether # ....
Bis(2-ethylhexyl)phthalate #
Bromodichloromethane # .
Bromomethane
Butanol
Butyl benzyl phthalate
Butyl-4,6-dinitrophenol 2-sec-
Cadmium
Carbon disulfide
Carbon tetrachloride #
Chlordane # • ....
Chloro-1 3-butadiene 2-{Chloroprene)
Chloroaniline p-
Chlorobenzene
Chlorobenzilate #
Chlorodibromomethane #
Chloroform #
Chioromethane
Chlorophenol 2- ^
Chromium (+3)
Chromium (+6) .*.
Chrysene
CoDoer
Cresol m-
Cresol o-
Cresol p-
Cumene :
DDD# ;. !
1000 yrs time horizon
Nonwastewater*
leach mg/1
6.30E+00
6.00E+00
3.00E-01
6.40E+00
1.00E+06
3.80E-05
3.40E-04
6.70E-P4
1.70E-02
4.57E+01
3.08E-02
1.67E+01
5.40E-03
6.80E-07
5 50E 04
1.10E-02
1.50E+01
1.00E+06
1 -10E 04
1 06E 03
3 68E 04
1.90E-03
1.80E+00
2.52E-03
2.87E+03
6.00E+00
1.10E+02
6.40E-02
1.18E+01
6.40E+00
1.61E-03
1.50E-02
1.60E-01
1.33E+00
7.50E-03
1.80E-03
1.70E-02
3.20E-01
1.32E+05
1.88E+01
2.70E-02
1.32E+05
3.20E+00
3.20E+00
•3.20E-01
2.50E+00
2.80E+03
Wastewater"
leach mg/1
3.60E+02
1.56E+01
7.80E-01
1.68E+01
1.00E+06
2.80E-04
1.10E-03
6.50E-02
5.30E-02
1.18E+02
7.92E-02
4.29E+01
1.80E-02
2.24E-06
5.50E-02
4.90E-01
4.00E+01
1.00E+06
1.10E-02
2.72E 03
1 92E 02
7.90E 03
1.80E+02
1.05E-02
5.63E+04
1.56E+01
1.10E+04
1.92E-01
3.05E+01
2.08E+01
1.40E-02
1.50E+00
4.20E-01
4.83E+00
1.02E+00
6.90E-03
5.80E 02
9.00E-01
3.40E+05
4.85E+01
2.90E+00
3.40E+05
8.80E+00
8.80E+00
8.80E-01
1.50E+01
1.00E+06
10,000 yrs time horizon
Nonwastewater'
leach mg/1
4.90E+00
6.00E+00
3.00E-01
6.40E+00
1.00E+06
3.80E-05
3.40E-04
3.70E 06
1.70E-02
5.30E-02
1.48E-04
1.55E+01
5.40E 03
6.80E 07
7.00E-06
6.60E 05
1.50E+01
1.00E+06
4.30E-06
3.20E-04
3.60E-04
1.90E-03
1.10E-03
2.52E 03
2.87E+03
6.00E+00
6.40E-f01
6.40E-02
1.1 OE 01
6.40E+00
1.61E 03
1.60E-04
1.60E-01
1.33E+00
5.70E-03
1.80E-03
1.70E 02
3.20E-01
2.37E+04
4.76E-01
1.20E-03
1.08E+03
3.20E+00
3.20E+00
320E 01
2.50E+00
2.80E+03
Wastewater"
leach mg/1
3.10E+01
1.56E+01
7.80E-01
1.68E+01
1.00E+06
2.60E-04
1.10E-03
4.70E-03
5.30E-02
1.36E-01
3.84E-04
3.32E+01
1.77E-02
2.24E-06
3.60E 03
1.60E-02
3.90E+01
1.00E+06
7.20E-04
8.27E-04
6.48E-04
7.00E-03
1.20E+01
8.54E-03
4.13E+04
1.56E+01
4.40E+02
1.92E-01
2.40E-01
1.84E+01
1.40E 02
1.00E 01
4.20E-01
4.76E+00
5.40E-02
6.60E-03
5.70E-02
9.00E-01
6.12E+04
1.24E+00
1.00E-01
2.79E+03
8.40E+00
8.40E+00
8.40E-01
1.50E+01
9.10E+05
p.
(0
<
o
O5
O
H
I
d
CD
s
I
CD
CD
CD
01
o
en
CD
P-
O5
O)
to
to
-------
TABLE B-1—COMPARISON OF GROUNDWATER MODELING RESULTS FOR 1000 vs. 10,000 YEARS TIME HORIZON (HQ=1 AND RisK=10-6)—Continued
: •"' ; [Threshold Chemical Concentrations for 1000 and 10,000 years Groundwater Modeling]
O5
S
to
No.
CAS No.
Name of Chemical
1000 yrs time horizon
Nonwastewater*
leach mg/l
Wastewater*1
leach mg/l
10,000 yrs time horizon
Nonwastewater*
leach mg/l
Wastewater**
leach mg/l
43
44
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
72
71
73
45
74
75
76
77
46
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
72559
50293
2303164
53703
96128
95501
106467
91941
75718
75343
107062
166592
156605
75354
120832
94757
78875
1 E+07
542756
1E+07
60571
84662
56531
.60515
119904
131113
119937
57976
105679
84742
99650
51285
121142
606202
117840
123911
122394
298044
115297
72208
106898
110805
141786
60297
97632
62500
100414
106934
96457
206440
DDE*
DDT, p,p'- #
Diallate*
Dibenz[a,h]- anthracene #
Dibromo-3-chloropropane1,2- #
Dichlorobenzene! ,2-
Dichlorobenzene! ,4- #
Dichloro- benzidine3,3 #
Dichlorodifluoromethane
Dichloroethane 1,1- #
Dichloroethanel ,2- # .-.
Dichloroethylene cis-1,2
Dichloroethylene trans-1,2 :...
Dichloroethylene1,1-(Vinylidene chloride:) #.
Dichlorophenol 2,4-
Dichlorophenoxyacetic acid, 2,4-
Dichloroprppane 1,2-# .....
Dichlpropropene trans-1,3- #
Dichloropropene 1,3-(mixture of isomers) # .
Dichloropropene cis-1,3- #
Dieldrin*
Diethyl phthalate
Diethylstilbestrol #
Dimethoate
Dimethoxybenzidine 3,3'- #
Dimethyl phthalate
Dimethylbenzidine 3,3'- # ."
Dimethylbenz[a]anthracene 7,12-
Dimethylphenol 2,4-
:Di-n-butyl phthalate
Dinitrobenzene 1,3-
Dinitrophenol 2,4- ....: ,
Dinitrotoluene 2,4-
Dinitrotoluene 2,6-
Di-n-octyl phthalate
Dioxane 1,4-#
Diphenylamine :
Disulfoton
Endosulfan(Endosulfan I and II, mixture)
Endrin ,.
Epichlorohydrin #
Ethoxyethanol 2-
Ethyl acetate
Ethyl ether
Ethyl methacrylate
Ethyl methanesulfonate #
Ethylbenzene
Ethylene dibromide (1,2-Dibromoethane) # .
Ethylene thiourea # :
Fluoranthene ;
3.30E-02
8.40E+03
4.60E-01
2.50E-04
1.14E-04
6.10E+00
1.16E-02
7.80E-04
1.19E+01
1.71E-03
1.62E-03
6.40E-01
1.12E+00
1.80E-04
1.80E-01
6.00E-01
2.30E-03
1.15E+03
8.50E-04
1.15E+03
5.40E-01
6.00E+01
1.20E-07
7.70E-01
1.20E-02
1.04E+03
1.89E-05
1.20E-03
1.19E+00
5.70E+01
6.40E-03
1.05E-01
1.12E-01
6.40 E-02
3.10E+02
1.36E-02
2.60E+00
1.30E+01
1 .OOE+00
3.20E+01
5.40E+03
1.50E+01
1.14E+02
1.05E+01
6.60E+00
1.17E+04
8.10E+00
1.50E-05
1.70E-04
7.50E+00
-3.30E+00
1.00E+06
2.80E+03
2.50E-02
7.20E-04
3.00E+01
6.80E-02.
5.40E-03
3.57E+01
9.90E-03
9.00E-03
1.72E+00
2.94E+00
5.90E-04
6.30E-01
1.56E+00'
2.60E-02
9.00E+04
2.80E-03
9.00E+04
2.90E+04
4.50E+02
9.20E-06
2.94E+01
3.36E-02
1.1.12E+04
8.10E-05
1.40E-01
3.78E+00
6.30E+03
1.68E-02
2.73E-01
3.01 E-01
1.68E-01
5.20E+04
4.24E-02
1.50E+01
5.80E+02
1.26E+01
2.70E+05
4.14E+05
3.90E+01
6.00E+02
2.73E+01
6.90E+01
9.30E+05
3.90E+01
4.20E-04
5.30E-04
7.80E+02
1.70E-04
5.40E-03
4.60E-01
6.30E-07
1.14E-04
6.10E+00
1.08E-02
7.20E-04
1.19E+01
6.00E-05
6.00E-05
6.40E-01
1.12E+00
1.80E-04
1.80E-01
6.00E-01
2.30E-03
1.15E+03
8.50E-04
1.15E+03
5.40E-01
5.40E+01
6.50E-08
7.70E-01
1.02E-02
3.00E+01
1.80E-05
2.80E-06
1.19E+00
2.50E+01
6.40E-03
1.05E-01
1.12E-01
6.40E-02
1.00E-01
1.36E-02
2.60E+00
1.30E+01
9.40E-01
3.20E+00
5.40E+03
1.50E+01
1.14E+02
1.05E+01
6.60E+00
1.17E+04
8.10E+00
1.50E-05
1.70E-04
1.70E+00
2.30E-01
2.04E+01
9.00E+01
1.80E-03
6.60E-04
3.00E+01
5.60E-02
4.20E-03
3.57E+01
1.60E-04
1.60E-64
1.68E+00
2.94E+00
5.90E-04
6.20E-01
1.56E+00
2.30E-02
9.00E+04
2.80E-03
9.00E+04
6.80E+02
1.86E+02
4.30E-07
2.94E+01
3.36E-02
7.80E+01
7.02E-05
1.30E-02
3.78E+00
2.30E+02
1.68E—02
2.73E-01
2.94E-01
1.68E-01
1.30E+03
4.24E-02
1.50E+01
4.60E+02
6.00E+00
6.60E+03
4.14E+05
3.90E+01
3.90E+02
2.73E+01
2.40E+01
9.30E+05
3.90E+01
3.60E-04
5.30E-04
2.70E+01
I
I
<
o
J—'
en
p
"Z
p
to
in
d
CD
n
CD
I
CD
CD
CD
Ul
TJ
s
V
o
CO
CD
-------
93
94
95
96
97
99
98
100
101
102
103
104
105
106
107
108
109
110
184
185
111
112
113
114
115
116
117
118
119
120
186
129
187
130
131
123
124
121
122
125
126
127
128
132
133
134
135
136
137
138
139
140
141
142
143
144
145
188
189
86737
50000
61486
110009
319857
319846
58899
76448
1024573
87683
118741
77474
67721
70304
193395
78831
78591
143500
7439921
7439976
126987
67561
72435
78933
108101
80626
298000
56495
74953
75092
7439987
91203
7440020
98953
79469
55185
62759
924163
621647
86306
1E+07
100754
930552
152169
56382
608935
82688
87865
108952
62384
108452
298022
1336363
2E+07
129000
110861
94597
7782492
7440224
Fluorene ...,.„„. „.,...........„......„,.„ „„
Formaldehyde [[[ „„„ „„.«. .. „,. ..
Focmtc acid „ ..
Furan „..„„«„.„...„„ .,..„.,.„.. ,„...,..........„ ...„..„,»..
HCH beta- 1. „ „, .. ..
HCH alpha- *
HCH (lindane) gamma- $ „ „ „ „ „„ „ „ ..„.
HeplachlorS „ „
Heptachlor epoxide S , .
Hexachloro-1 ,3-butadene d
Hexachlorobenzene # „
Hexachlorocyclopentadiene .'.
Hexachloroethane #
Hexachlorophene
lndeno[1 ,2,3-cd]pyrene
Isobutyl alcohol
Isophorone #
Kepone #
Lead
Mercury
Methacrylonitrile
Methanol
Methoxychlor
Methyl ethyl ketone .
Methyl isobutyl ketone
Methyl methacrylate
Methyl parathion
Methylcholanthrene 3- #
Methylene bromide
Methylene Chloride #
Molybdenum
Naphthalene
Nickel
Nitrobenzene
Nitropropane 2-
N-Nitrosodiethylamine # ;
N— Nitrosodimethylamine # ...
N— Nitroso-di-n-butylamine #
N-Nitroso-di-n-propylamine #
N— Nitrosodiphenylamine #
N-Nitrosomethylethylamine #
N— Nitrosopiperidine #
N-Nitrosopyrrolidine #
Octamethyl pyrophosphoramide
Parathion (ethyl)
Pentachlorobenzene
Pentachloronitrobenzene (PCNB) #
Pentachlorophenol #
Phenol
Phenyl mercuric acetate
Phenylenediamine, 1,3- .
Phorate
Polychlarinated biphenyls (Aroclors) #
Pronamide
Pyrene
Pyridine
Safrole # :
Selenium
Silver
5 OOE+00
1 05E+01
1.05E+02
6.00E-02
2.10E-04
1 10E-01
6.93E+01
1. OOE+06
4 50E+01
2 30E+02
3.50E+03
1 OOE+06
402E-02
1 40E 02
4 60E 03
1 50E+01
1.62E 01
5 80E 05
1 32E+05
1 81E+01
6 OOE 03
3 OOE+01
1 OOE+06
3 OOE+01
3.00E+00
810E+00
2 34E+01
1 70E 03
6 80E 01
6 80E 01
2 70E+00
9 95E+00
320E-02
1.02E-06
340E-06
360E-05
1 70E-05
4 80E-02
6 80E - 06
3 40E 06
680E-05
1 05E-01
1 16E+04
1 44E+01
237E-02
4 20E 04
3 20E+01
450E-03
3 OOE -01
1 OOE+06
9 10E-04
5 70E+00
1 40E+01
6 OOE 02
9 50E 04
1 38E+00
1.32E+00
3 90E+02
2 73E+01
2 73E+02
1.60E-01
1.30E-03
2 10E+01
1.19E+02
1. OOE+06
3 15E+04
2 10E+00
3.50E+01
1 OOE+06
110E+00
1 50E+00
5 OOE -01
3 90E+01
549E-01
4 80E 03
3 40E+05
4 67E+01
1 64E-02
7 80E+01
1 OOE+06
7 80E+01
8.00E+00
8 40E+01
9 90E+02
1 70E 01
2 32E+00
2 36E+00
1 40E+01
2 56E+01
8 40E 02
318E-06
1 Q6E-05
1 32E 04
540E-05
2 60E 01
2 16E-05
1 06E 05
2 12E-04
280E-01
5 60E+05
1 56E+03
2 19E+00
2 50E 03
8 40E+01
1 17E-02
780E-01
1 OOE+06
8 80E 02
2 19E+01
1 50E+03
1 56E 01
380E 03
3 57E+00
3.40E+00
3 40E+00
1 05E+01
1.05E+02
6 OOE-02
2.10E-04
1 10E-01
6.93E-01
1 OOE- 06
4 50E-01
6 90E-03
1 10E-04
1 OOE-06
330E-02
1 40E-03
240E— 05
1 50E+01
1 62E-01
320E — 05
1 16E+01
1 38E 01
6 OOE -03
3 OOE+01
1 OOE+06
3 OOE+01
3 OOE+00
8 10E+00
2 34E+01
1 40E 06
1 goE 01
1 50E 02
2 70E+00
4 89E+00
320E — 02
1 02E-06
3 40E 06
3 60E 05
1 70E-05
4 60 E 02
680E-06
3 40E 06
• 6 80E 05
1 05E 01
1 16E+04
570E-01
540E-03
4 1 0E 04
3 20E+01
450E-03
3 OOE 01
1 OOE+06
4 80E 06
5 70E+00
1 70E+00
6 OOE 02
9 50E 04
3 57E 01
8.90E-02
2.20E+01
2 73E+01
2 73E+02
1 56E-01
1 30E-03
2 10E+01
1 19E+02
1 OOE+06
7 83E+02
8 10E+02
2 23E+02
1 OOE+06
216E 01
520E-01
1 70E 02
3 90E+01
531E-01
2 20E 04
3 OOE+01
2 96E 01
1 56E-02
7 80E+01
1 OOE+06
7 80E+01
7 80E+00
2 82E+01
7 80E+01
1 20E 02
2 32E+00
3 90 E 02
1 40E+01
1 05E+01
8 40E 02
3 18E-06
1 06E 05
1 22E 04
5 30E-05
2 OOE 01
2 12E-05
1 06 E 05
2 12E-04
2 73E 01
4 40E+05
5 10E+00
8 10E-02
2 OOE 03
8 40E 01
1 17E 02
7 8QE 01
1 OOE+06
6 10E 03
2 13E+01
5 40E+01
1 56E 01
3 50E 03
9 27E 01
1.91E-01
(?
CD
s.
I
tn
5?
a-
CO
d
CD
O
CD
I-
CD
CO
-------
TABLE B-1 .—COMPARISON OF GROUNDWATER MODELING RESULTS FOR 1000 vs. 10,000 YEARS TIME HORIZON (HQ=1 AND RiSK=10-6)—Continued
[Threshold Chemical Concentrations for 1000 and 10,000 years Groundwater Modeling]
No.
146
• 147
148
149
151
152
153
154
190
155
156
158
157
159
160
161
162
163
164
165
166
168
167
170
169
171
172
173
191
174
175
192
CAS No.
57249
100425
1746016
95943
630206
79345
127184
58902
3689245
7440280
108883
95807
95534
106490
8001352
75252
76131
120821
71556
79005
79016
75694
95954
88062
93765
93721
96184
99354
126727
7440622
75014
1330297
7440666
Name of Chemical
Styrene . ... .. ..,
TCDDioxin 2 3 7 8 # ...
Tetrachlorobenzene 1 2 4 5- # ...
Tetrachloroethane 1 1 1 2- # ...
Tetrachloroethane 1122-1
Tetrachloroethylene' . . ...
Tetrachlorophenol 2346-
Tetraethyl dithiopyrophosphate
Thallium
Toluene
Toluenediamine 2 4- # . . . .
Toluidine o- # .......
Toluidine p- # •
Toxaphene (chlorinated camphenes) #
Tribromomethane #
Trichloro-1 2 2-trifluoro- ethane 112-
Trichlorobenzene 124- . .
Trichloroethane 1 11- . . . .
Trichloroethane 1 1 2- # . . . .
Trichlorofluoromethane .'...;
Trichlorophenol 2,4,5-
Trichlorophenol 2 4 6- # ....
Trichlorophenoxyacetic acid 245- ' . . . .
Trichlorophenoxypropionic acid
Trichloropropane 1,2,3- .„
Trinitrobenzene (1 3 5-Trinitrobenzene) sym- ... ....
Tris (2 3-dibromoprophyl) phosphate B1 9 # .
Vanadium :
Vinyl chloride # .......
Xylenes (total)
Zinc :
1 000 yrs time horizon
Nonwastewater*
leach mg/l
1.60E-02
1 .54E+01
2.70E-08
6.00E-02
7.80E-03
9.60E-03
6.80E-01
5.80E-01
1 .OOE+06
3.96E+02
1 .26E+01
5.10E-05
6.80E-04
6.80E-04
1.10E-01
. 1.80E-02
2.40E+03
2.10E+00
5.00E+00
1.80E-03
1.44E-02
1.60E+01
4.20E+00
1.52E-02
6.40E-01
4.80E-00
3.40E-01
3.00E-03
9.90E-05
8.82E+00
6.80E-05
1.47E+02
1 .08E+02
Wastewater**
leach mg/l
4.50E-02
6.51 E+01
2.70E-06
5.70E+00
7.50E-02
2.92E-01
2.08E+00
1.90E+00
1. OOE+06
1.02E+03
4.20E+01
1.59E-04
2.24E - 03
2.24E-03
6.70E+02
6.80E-02
1.40E04
1.70E+02
1.20E+02
7.40E-03
5.28E-02
4.90+01
2.00E+01
5.76E-02
1.G8E+00
1.32E+00
2.20E+00
8.00E 03
2.52E-03
2.27E+01
2.16E-04
9.10E+02
2.79E+02
1 0,000 yrs time horizon
Nonwastewater*
leach mg/l
1.60E-02
1 .54E+01
1.80E-10
3.20E-02
7.80E-03
8.00E-03
6.80E-01
5.80E-01
1. OOE+06
1.92E-02
1.26E+01
5.10E-05
6.80E-04
2.24E-03
1.10E-01
1.80E-02
2.40E+03
1.30E+00
4.60E+00
1.80E-03
1.28E-02
1.60E+01
4.20E+00
1 .52E - 02
6.40E 01
4.80E-01
3.40E-01
3.00E-03
9.90E-05
3.71 E+00
6.00E 05
1.47E+02
3.84E+01
Wastewater**
leach mg/l
4.50E-02
6.37E+01
1.90E-07
2.30E-01150
7.50E-02
2.40E-02
2.04E+00
1.90E+00
1.00+06
5.00E-02
4.13E+01
1.59E-04
2.24E-03
2.24E-03
2.20E+01
6.40E-02
1.10E+04
9.30E+00
1 .20E+02
7.00E-03
3.84E-02
4.80E+01
4.40E+01
5.36E-02
1.68E+00
1.26E+00
1.10E+00
7.80 E- 03
2.52E-03
9.58E+00
1.56E-04
8.60E+02
9.90E+01
O)
O5
*>
ISJ
en
g
CB
l-i
<
o
h—'
O3
O
z
p
"t-0
Ul
a
CD
O
CD
It
CD
CO
CD
en
CD
a
For Trichloroethane 1,1,1 the MCL, 0.20 mg/L was used in conic, calculation.
'Represents the lowest results from either landfills, waste piles, or land application units waste management scenarios.
"Represents results from surface impoundments.
# Carcinogen.
CD
en
-------
Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66427
Appendix C
TABLE C-1.—SUMMARY OF CONSTITUENT-SPECIFIC EXIT LEVEL DEVELOPMENT USING TOXICITY BENCHMARKS
CAS No.
83-32-9
208-96-8 ....
67-64-1 ......
75-05-8
98-86-2
75-36-5 —
S91-08-2 ....
53-96-3
107-02-8 ....
79-06-1 —
107-13-1 ....
1402-68-2 ..
116-06-3 ....
300-00-2 ....
107-18-6 ....
107-05-1 ....
92-67-1 ......
2763-96-4 ..
504-24-5 ....
61-82-5 ......
62-53-3
120-12-7 ...
7440-36-0 .
140-57-8 ...
7440-38-2 .
2465-27-2 .
115-02-6...
7440-39-3 .
71-43-2
92-87-5 ......
106-51-4 ....
98-07-7 ~™
SO-32-8 —
205-99-2 ....
205-82-3 ....
207-06-9 ._
191-24-2 ..„
100-51-6 ....
100-44-7 ....
56-55-3 —
225-51-4 ....
7440-41-7 ..
39638-32-9
111-44-4 ....
117-81-7 ....
542-88-1 ....
598-31-2 ....
76-27-4 —
75-25-2
101-55-3 ....
357-57-3 ....
71-36-3 ......
88-85-7 —
85-68-7 ......
7440-43-9 ..
86-74-8
75-15-0 —
353-50-4 ....
56-23-5
75-87-6
305-03-3....
57-74-9 ......
494-03-1 ....
126-99-8 ....
107-20-0 ....
106-47-8 ....
108-90-7 ....
510-15-6 ....
124-48-1 ....
75-00-3 ......
110-75-8....
67-66-3
Name
Acenaphthene
Acenaphthylene
Acetone
Acetonilrile
Acetophenone
Acetyl chloride
AcotyKMhiourea.1-
Acetylaminolluorene, 2-
Acrolein
Acrytonitrile
Allatoxins
Aldicarb
AkJrin
Ally) alcohol
Allyl chiotkle
Amlnobiphenyl, 4-
Aminomelhyl-3-isoxazolol, 5-
Amlnopyridine, 4- ,
Amitrc4a
Aniline
Anthracene
Antimony
Aramite
Arsenic
Auramine
Azasedne
Barium
Benzene
BenzkJine
Benzoqulnone, p-
Benzotrichtoride
Benzo(a)pyrene
Benzo(b)lluoranlhene
Benzo(j)fluoranthene
Benzo(k)fluoranthene
Benzc{g>h,i,]perylene
Benzyl alcohol
Benzyl chloride
Benz(a)anthracene
Benz[c]acridine
Beryllium
Bis (2-chtoroisopropyl) ether .
Bis(2-ch!orethyljether
Bis(2-ethylhexyl)phthalate
Bisjchloromethyljeither
Bromoacetone
Bromodfchloromethane
Bromoform
(Tribromomethane).
Bromophenyl phenyl ether, 4-
Bruclne
Butanol
Bufyl-4,6-dinilrophenol, 2-
sec- (Dmosob).
Butylbenzylphthalate
Cadmium
Carbazole
Carbon disullkte
Carbon oxylluoride
Carbon telrachloride
Chloral
Chlorambucil
Chtordane
Chlomaphazin
Chtofo-1, 3-butadiene, 2-
(Chtoroprene).
Chloroaceialdehyde
Chtoroaniline. p-
Chtorobenzene
Chlorobenzilate
Chtorodibromomethane
Chtoroethane (ethyl chloride)
Chtoroelhyl vinyl ether, 2-
Chloroform
WW totals (mg/l)
Multipath
modeled
exit level
49.5
232000
6.58
5960
0 00248
3.67
0.00428
5.640E-07
0.0742
0.444
8210
40.5
0.0209
0.00015
0.00231
0.000805
22500
1.13
0.0138
10.1
0.569
0.00141
0.00044
33.3
0.178
38600
15.4
235
1600
0.738
0.0115
0.000014
0.515
517
1.5
0.0731
16.3
0.00759
Ground-
water
modeled
exit level
31.2
15.6
0.78
16.8
0.00026
0.001 1
0.00469
0.053
0.136
0.000384
33.2
0.0177
2.240E-06
0.00364
0.0164
39
3.9
0.000717
0.000827
0.007
0.000648
12.4
0.00854
0.064
15.6
0.192
437
0.24
18.4
0.014
0.0998
0.42
4.76
0.054
0.0066
0.057
Extrapo-
lated exit
level
0.00285
0.023
0.11775
0.02762
14.7
0.0069415
39
0.02762
0.159
0 02762
0.0069415
0 00285
14.7
0.159
0.159
14.7
0081
0.00285
0.00285
0.00285
0.00285
0.023
0.023
0.023
0.159
0.159
0.023
0.081
0081
0081
0.023
0.023
0081
WWEQC
0.0018
0.02
0.2
0.015
0.00158
1
0.02
0.013
0.01
0.008
0.05
0.000034
0.002
0.02
0.00023
0007
0.0008
0.02
0.0005
0.001
0.00004
0.0025
0.01
0.000023
0.000018
0.0002
0.0002
0.0008
0.00074
5 OOOE 06
0.000013
0.0005
0.00003
0.00145
0.0003
0.00027
0.005
0.00008
0.0002
0.01
20
0.014
0.00029
0.000042
0.00005
0.00121
0.00021
O.OOOQ4
0.002
0.00066
0.00004
0.00504
0.00007
0.005
0.00003
NWW totals (mg/kg)
Multipath
modeled
leach level
9480
17400
923
1210
2.63
0.00436
0.961
0.000444
258
4.21
8.72
0.17
2080
109
0.0000298
0.227
3.7
2740
37.5
0.1
0.0591
0.944
0.115
225
19
173
18200
772
1 87
14.1
330
8.54
0.00976
288
142
2470
6.82
27.5
6.74
Extrapo-
lated leach
level
3.9
30.85
1.66
3.28
6900
0.194
36700
3.28
19.955
3.28
0 194
3.9
6900
19955
19955
6900
142
3.9
3.9
3.9
3.9
30.85
30.85
30.85
19955
19955
30.85
142
142
142
30.85
30.85
142
NWW
EQC
0.0742
0.7
0.027
0.014
0.03
70
1
0.075
0.1
0.7
1
0.0006
0.002
1
0.0132
0.5
2
1
0.3031
0.2
0.0001
0.042
0.7
0.004
0.0621
0.0699
0.01
0.7
0.7
0.034
0.00276
0.0826
0.03
0.1
0.0586
0.0651
0.143
0.03
0.0012
0.02
0-7
0.23
0.042
0.049
0.2
0.0002
0.02
ab'bi's
""b"boo99
0.0592
0.0002
0.069
0.00085
0.005
0.005
0.002
NWW leach (mg/l)
Ground-
water
' modeled
each level
4 g
6
0.3
6.4
0.000038
0.00034
3.670E-06
0.017
0.053
0.000148
15.5
0.0054
6.800E-07
7.040E-06
0.0000661
15
15
4.300E-06
0.00032
0.0019
0.00036
0.00112
0.00252
0.018
6
0.064
64
0.11
6.4
0.00161
0.000163
0.16
1.33
0.0057
0.0018
0.017
Extrapo-
lated each
level
0.0000661
0.015
6.4
0.00884
10.5
0.48
15
0.00884
0.105
0.00884
0.48
aboboeei
10.5
0.105
0.105
10.5
0.0317
0.0000661
0.0000661
0.0000661
0.0000661
0 015
0.015
0.015
0.105
0 105
0 015
0 0317
0.0317
0.0317
0 015
0.015
0.0317
WWEQC
0.0018
0.02
0.2
0.015
0.00158
1
0.02
0.013
0.01
0.008
0.05
0.000034
0.002
0.02
0.00023
0.007
0.0008
0.02
0.0005
0.001
0.00004
0.0025
0.01
o"bo6o23
0.000018
0.0002
0.0002
0.0008
0.00074
5.000E-06
0.000013
0.0005
0.0003
0.00145
0.0003
0.00027
• 0.005
0.00008
0.0002
0.01
20
0.014
0.00029
0.000042
0.00005
0.00121
0.00021
""aob'bb'i
""""b"6o2
0.00066
0.00004
0.00504
^0,00007
:'- 0.005
o.oobbs
-------
66428 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
TABLE C-1 .—SUMMARY OF CONSTITUENT-SPECIFIC EXIT LEVEL DEVELOPMENT USING TOXICITY BENCHMARKS—
Continued
CAS No.
59-50-7
107-30-2 ....
91-58-7
95-57-8
7005-72-3 ..
5344-82-1 ..
542-76-7- ....
7440-47-3 ..
218-01-9 ....
6358-53-8 ..
7440-48-4 ..
7440-50-8 ..
108-39-4 ....
95-48-7
106-44-5 ....
4170-30-3 ..
57-12-5
14901-08-7
108-94-1 ....
131-89-5 ....
50-18-0
20830-81-3
72-54-8
53-19-0
72-55-9
3424-82-6 ..
50-29-3
789-02-6 ....
2303-16-4 ..
132-64-9 ....
192-65-4 ....
189-64-0 ....
189-55-9 ....
194-59-2 ....
226-36-8 ....
53-70-3
224-42-0 ....
96-12-8 ......
764-41-0 ....
110-57-6 ....
96-23-1
95-50-1
541-73-1 ....
106-46-7 ....
91-94-1
75-71-8
75-34-3
107-06-2 ....
75-35-4 ......
156-59-2 ....
156-60-5 ....
111-91-1 ....
98-87-3
1.20-83-2 ....
87-65-0
94-75-7 ......
78-87-5
542-75-6 ....
10061-^)1-5
10061-02-6 .
60-57-1 ..'....
1464-53-5 ..
84-66-2.......
311-45-5 ....
56-53-1
94-5&L6
60-51-5
131-11-3 ....
77-78-1 ..;...
Name
Chloro-m-cresol, p-
Chloromethyl methyl ether ....
Chloronaphthalene, 2-
Chlorophenol, 2-
Clorophenyl phenyl ether, 4-
Chlorophenyl thiourea, 1-c~ ..
Chloropropionitrile, 3-
Chromium
Ghrysene
Citrus red No. 2
Cobalt
Copper
Cresol, m-
Cresol, o-
Cresol, p-
Crotonaldehyde
Cyanide
Cycasin
Cyclohexanone
Cyclohexyl-4,6-dinitrophenol,
2-.
Cyclophosphamide
Daunomycin
ODD
ODD (o.p1)
DDE
DDE (O,p1)
DDT
DDT (op1)
Diallate
Dibenzofuran
Dibenzo[a,e]pyrene
Dibenzo[a,h]pyrene
Dibenz(a,h)acridine
Dibenz(a h)anthracene
Dibenz[a j]acridine
Dibromo-3-chloropropane,
1,2-.
DichIoro-2-butene 1 4-
Dichloro-2-butene, trans-1 ,4-
Dichloro-2-propanol 1 3-
Dichlorobenzene 1 2-
Dichlorobenzene, 1,3-
Dichlorobenzene, 1 ,4-
Dichlorobenzidine, 3,3'-
Dichlorodifluoromethane
Dichloroethane, 1 ,1-
Dichloroethane, 1 ,2-
Dichloroethylene 11-
Dichloroethylene, cis-1 ,2-
Dichloroethylene, trans-1 ,2- ..
Dichloromethoxy ethane
Dichloromethylbenzene
(benzal chloride).
Dichlorophenol 2 4-
Dichlorophenol, 2,6-
Dichlorophenoxyacetic acid,
2,4- (2,4-D).
Dichloropropane, 1;2-
Dichloropropene, 1,3-
Dichloropropene, cis-1 ,3-
Dichloropropene, trans-1 ,3- ..
Dieldrin
Diepoxybutane, 1 ,2,3,4-
(2,2'-bioxirane).
Diethyl phthalate
Diethyl-p-nitrophenyl phos-
phate.
Diethylstibestrol
Dihydrosafrole
Dimethoate
Dimethyl phthalate
Dimethyl sulfate
WW totals (mg/l)
Multipath
modeled
exit level
134
1300
1.32
674
615
656
63.5
0.000126
9.110E-06
0.0000181
0,26
8.440E-06
0.0723
15.4
3.01
0.0037
14.7
37.4
0:00698
0.00345
30000
44200
6.94
58.5
0.303
0.00476
0.00485
0.0049
0.000059
3560
7.720E-07
38.1
200000
Ground-
water
modeled
exit level
0.9
1.24
0.1
2790
8.4
8.4
0.84
913000
0.228
20.4
90.1
0.00176
0.00066
29.5
0.056
0.0042
35.7
0.00016
0.00016
0.00059
1,68
2.94
0.62
1.56
0.023
0.0028
90000
90000
682
186
4.290E-07
29.4
78
Extrapo-
lated exit
level
0.081
0.023
0.081
0.023
0.023
' 0.081
14.7
1.24
7.8
0.159
14.7
7.8
0.0252
0.159
14.7
0.0069415
0.0069415
0.0069415
8.4
0.00285
0.00285
0.00285
0.00285
0.00285
0.00285
0.023
0.023
0.081
0.023
0.023
0.023
0.023
14.7
0.159
14.7
0.11775
WWEQC
0.02
0.01
0.00058
0.01
0.1
0.002
0.00015
0.5
0.0007
0.00046
0.00055
0.00046
0.06
0.2
10
0.1
0.00005
0.000058
0.000081
0.00063
0.01
0.0002
0.0002
0.0002
0.01
0.0002
0.00003
0.001
0.00026
0.005
0.005
0.01
0.00003
0.005
0.00004
0.0024
0.0001
0.00004
0.00006
0.00012
0.00012
0.00006
0.01
0.005
0.00041
0.01
0.00029
0.00004
0.0009
0.00069
0.00094
0.000044
0.005
0.00025
0.0078
0.05
0.00029
0.00064
NWW totals (mg/kg)
Multipath
modeled
leach level
104
9.76
34.6
5.91
21500
27400
2550
0.00648
0.000936
0.00315
.1.26
0.000155
0.663
50000
63.9
0.0524
8070
24.2
6.1
2.55
5400
13800
769
3140
16.9
32.4
2.64
2.67
0.00176
4490
2.470E-1 1
1.6
3
Extrapo-
lated leach
level
142
30.85
142
30.85
30.85
142
6900
8.72
1210
19.955
6900
1210
2.991
'19955
6900
0.194
0.194
0 194
27400
3.9
3.9
3.9
3.9
3.9
3.9
30.85
30.85
142
30.85
30.85
30.85
30.85
6900
19955
6900
1.66
NWW
EQC
1
0.005
0.7
0.0758
0.7
0.5
0.003
0.084
5
0.5
0.035
0.027
0.035
4
0.2
10
7
0.0012
0.0006
0.0006
0.023
0.7
0.01
0.01
0.01
0.7
0.01
0.084
0.7
0.0003
0.005
0.005
0.05
0.0002
0.7
0.0001
0.116
0.0052
0.0002
0.0001
0.0014
0.02
0.0006
0.7
0.3
0.0788
0.7
0.00011
0.0001
0.0003
0.0003
0.0003
0.0006
0.005
0.022
. i
3
0.0691
0.013
NWW leach (mg/l)
Ground-
water
modeled
each level
0.32
0.476
0.00119
1080
3.2
3.2
0.32
2800
0.0000623
0.0054
0.46
6.340E-07
0.000114
6.1
0.0108
0.00072
11.9
0.00006
0.00006
0.00018
0.64
1.12
0.18
0.6
0.0023
0.00085
1150
1150
0.54
54
6.500E-08
0.77
30
Extrapo-
lated each
level
0.0317
0.015
0.0317
0.015
0015
0.0317
10.5
0.4165
6.2
0.105
10.5
6.2
0.0083
0 105
10.5
0.48
0.48
0.48
3.2
0.0000661
0.0000661
0.0000661
0.0000661
0.0000661
0.0000661
0.015
0.015
0.0317
0.015
0.015
0.015
- 0.015
10.5
0 105
10.5
6.4
WWEQC
0.02
o'.b'i'
0.00058
0.01
0.1
0.002
0.00015
0.5
0.0007
0.00046
0.00055
0.00046
0.06
0.2
10
0.1
0.00005
0.000058
0.000081
0.00063
0.01
0.001
0.0002
0.0002
0.01
. 0.0002
0.00003
0.001
0.00026
0.005
0.005
0.01
0.00003
0.005
0.00004
0.0024
0.0001
0,00004
0.00006
0.00012
0.00012
0.00006
0.01
0.005
0.00041
0.01
0.00029
0.00004
0.0009
0.00069
0.00094
0.000044
0.005
0.00025
0.0078
0.05
0.00029
0.00064
-------
Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66429
TABLE C-1.—SUMMARY OF CONSTITUENT-SPECIFIC EXIT LEVEL DEVELOPMENT USING TOXICITY BENCHMARKS—
Continued
CAS No.
60-11-7 —
119-93-7 ....
57-97-6 —
79-41-7 —
122-09-8 ....
105-67-9 ....
119-90-4 ....
84-74-2 ......
99-65-0 ......
100-25-4 ....
534-52-1 ~.
51-28-5 ......
121-14-2 .„.
606-20-2 ....
117-84-0 ....
123-91—1
122-39-4 ....
122-66-7 ....
298-04-4 ....
541-53-7 ....
115-29-7 ....
959-98-8 ....
332-13-65-
9,
1031-07-8 ..
145-73-3 ....
72-SO-8 ...,„
7421-93-4 ..
53494-70-5
106-89-8 ....
51-43-4 ......
110-80-5 ....
141-78-6 ....
51-79-6 —
107-12-0 ....
60-29-7
97-63-2
62-50-0 ......
100-41-4 ....
106-93-4 ....
75-21-8
96-45-7 ......
151-56-4 ....
52-56-4 —
640-19-7 ....
62-74-8
206-44-0 ....
86-73-7 ......
16984-48-8
SO-00-0 ......
64-18-6 *,
765-34-4 ....
319-86-8 ....
78-44-8
1024-57-3 ..
87-68-3 ......
118-74-1 ....
319-84-6 ....
319-85-7 ....
58-89-9
77-47-4 ......
67-72-1
70-30-4 ......
1888-71-7 ..
757-58-4 ....
591-78-6 ....
302-01-2 ....
i«a-3<»-s ....
Name
Kmethylaminoazobenzene,
P--
Dimethylbenzidine, 3,3'-
Olmethylbenz(a)anihracene,
7,12-.
Dimelhylphsnethylamine,
alpha, alpha-.
Dimelhyoxybenzidine, 3,3'- ..
Dinitrotoluene, 2,4-
DlphQnylhydrazirie 1 2—
Disulloton
Dilhiobiuret
Endosutfan .
Endosulfan II
Endothall
Endrtn .
Ethy) carbamate
Ethyl ether
Ethyl methanesulfonate ........
Ethytene oxide
Flouracetic acid, sodium salt
Fluoride
Formic Acid
Glycidylaldehyde
HCH delta-
Hexachtoro-i,3-butadiene
Hexachtofocyctohexane,
alpha-(alpha-BHC).
Hexachtorocyclohexane.
beta-(beta-BHC).
Hexachtorocyctohexane,
gamma-(Lindane).
Hexachlofocyclopentadiene ..
Hexachtofopropene
Hoxaothyl tetraphosphate
Hydrazine
Inrinnn (1 .2.3-cdl Dvrene
WW totals (mg/l)
Multipalh
modeled
exit level
0.000625
3.820E-06
151
1.78
883
1.28
50.2
10.7
12.9
0.002
558
29
0.0131
6.62
0.0729
0.335
14.7
25500
0.0055
74.5
0.000928
17.7
1580
1310
0.0158
0.0000237
0.000528
0.00788
0.000424
0.000142
0.000445
0.000783
0.00521
0.049
5.150E-06
0.00285
Ground-
water
modeled
exit level
0.0000702
0.00464
3.78
0.0336
227
0.0168
0.273
0.294
0.168
1260
0.0424
14.7
458
6
6550
414000
39
390
27.3
24
930000
39
0.00036
0.00053
27.5
22.4
27.3
273
7.8
783
0.0806
0.0226
21
0.0013
119
" 0.212
0.0521
0.0165
Extrapo-
lated exit
level
0.02762
0081
0.159
0.0252
0.0252
0.159
0.11775
0.0069415
0.0069415
0.0069415
0.0069415
0.0069415
0.0069415
0 159
14.7
0.159
14.7
0 159
0,0069415
0.023
0.0069415
0
0.0069415
0.081
14.7
7.8
0.159
WWEQC
0.01
0.0033
0.00037
0.05
0.00047
0.0077
0.00033
0.00011
0.04
0.05
0.00042
0.00002
0.00031
0.000042
0.012
0.00151
0.01
0.00007
0.00004
0.0003
0.0004
0.0004
0.1
0.00039
0.0005
0.0005
0.06519
1.16
0.009
0.05
0.1
0.00153
0.00345
0.00106
0.00006
0.00006
0.001
0.02
0.00021
0.00021
0.05
0.0232
0.2
0.0002
0.00004
0.000032
0.0001
0.00161
0.000035
0.000023
0.000025
0.00018
1.600E-06
0.207
0.01
0.005
0.000043
NWW totals (mg/kg)
Multipath
modeled
leach level
0.00062
0.00263
11300
0.236
90000
5.54
56.1
213
86.3
4480
13.2
11800
42.6
73.1
026
44
6900
272000
41200
3420
00133
550000
0.00745
0.51
5970
89800
48.8
301000
1210
7.79
0.0264
36.4
0.0116
0.0333
0.12
0.102
1450
80.6
0.0000241
3.9
Extrapo-
lated leach
level
3.28
142
19.955
2.991
2.991
19.955
1.66
0.194
0.194
0.194
0.194
0.194
0.194
19.955
6900
19.955
6900
19955
0.194
30.85
0 194
0
0.194
142
6900
1210
19.955
NWW
EQC
0.7
0.7
0.039
3
0.052
7
0.249
0.25
3
3
0.03
0.26
0.25
0.139
0.0005
0.041
0.7
0.0035
0.0005
0.009
0.003
0.04
0.0036
0.02
0.03
0.0714
2.03
0.18
3
0.1
0.00319
0.001 1
0.018
0.0002
0.0001
0.07
. 1
0.084
0.08
4
10
0.0006
0.0008
0.0006
0.046
0.0723
0.0008
'0.0006
0.002
0.092
0.0206
1.87
0.7
0.005
0.3
0.0748
NWW leach (mg/l)
Ground-
water
modeled
each level
0.000018
2.760E-06
1.19
0.0102
25.2
0'.0064
0.105
0.112
0.064
0.1
0.0136
2.6
13
0.94
32
5400
15
114
10.5
6.6
11700
8.1
0.000015
0.00017
1.74
3.4
10.5
105
6.2
0.45
0.00691
0.000113
' 0.11
0.00021
0.693
0.033
, 0.00136
0.0000241
Extrapo-
lated each
level
0.00884
0.0317
0.105
0.0083
0.0083
0.105
6.4
0.48
0.48
0.48
0.48
0.48
0.48
0.105
10.5
0.105
10.5
0.105
0.48
0.015
0.48
0
0.48
0.0317
10.5
6.2
0.105
WWEQC
0.01
0.0033
0.00037
0.05
0.00047
0.0077
0.00033
0.0001 1
0.04
0.05
0.00042
0.00002
0.00031
0.000042
0.012
0.00151
0.01
0.00007
0.00004
0.0003
0.0004
0.0004
0.1
0.00039
0.0005
0.0005
0.06519
1.16
0.0009
0.05
0.1
0.00153
;0.00345
0.00106
0.00006
0.00006
: Q.001
0.02
, .0:00021
•-0-.00021
-- 0.05
0.0232
•'- • 0.2
-0'.0002
•'•0.00004
0.000032
r- 0.0001
•0100161
-,0:000035
0.000023
- 0,000025
r;'b:6ooi8
,r.600E-06
"-"'0.207
'.,'"'''0.01
(to'l'-iv: •
' e.-O-PPS
•0".b'ooo43
-------
66430 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
TABLE C-1 .—SUMMARY OF CONSTITUENT-SPECIFIC EXIT LEVEL DEVELOPMENT USING TOXICITY BENCHMARKS—
. Continued
CAS No.
74-88-4
78-83-1
465-73-6 ....
78-59-1
120-58-1 ....
143-50-0 ....
303-43-4 ....
7439-92-1 ..
108-31-6 ....
123-33-1 ....
109-77-3 ....
148-82-3 ....
7439-97-6 ..
126-98-7 ....
74-93-1
67-56-1
91-80-5
16752-77-5
72-43-5
74-83-9
74-87-3
78-93-3
1338-23-4 ..
60-34-4
108-10-1 ....
80-62-6
66-27-3
91-57-6
298-00-0 ....
75-55-8
56-49-5
74-95-3
75-09-2
101-14-4 ....
70-25-7 ......
56-04-2
50-07-7
7439-98-7 ..
91-20-3
130-15-4 ....
86-88-4
134-32-7 ....
91-59-8
7440-02-0 ..
54-11-5
88-74-^
99-09-2
100-01-6 ....
99-95-3
55-86-7
51-75-2
126-85-2 ....
302-70-5 ....
55-63-0
99-55-rS
88-75-5
100-02-7 ....
79-46-9
56-57-5
55-18-5
62-75-9
924-16-3 ....
10595-95-6
1116-54-7 ..
621-64-7 ....
86-30-6
4549-40-0 „
59-89-2
759-73-9 ..;.
684-93-5 ....
Name
lodomethane
Isobutyl alcohol
Isodrin
Isophorone
Isosafrole
Kepone
Lasiocarpine
Lead
Maleic anhydride
Maleic hydrazide
Malononitrile
Melphalan ...
Mercury
Methacrylonitrile
Methanethiol
Methanol
Methapyrilene
Methomyl
Methoxychlor
Methyl bromide
(Bromomethane).
Methyl chloride
(Chloromethane).
Methyl ethyle ketone
Mehtyl ethyl ketone peroxide
Mehty hydrazine
Methyl isobutyl ketone
Methyl methacrylate
Methyl methanesulfonate
Methyl naphthalene 2-
Methyl paratyhion
Methylaziridine, 2-
Methylcholanthrene, 3-
Methylene bromide
Methylene chloride
Methylenebis, 4,4'-(2-
chloroaniline).
Methyl-nitro-nitrosoguanidine
(MNNG).
Methylthiouracil
Mitomycin C
Molybdenum
Naphthalene
Naphthoquinone, 1,4-
Naphthyl-2-thiourea, 1-
Naphthylamine, 1-
Naphthylamine, 2-
Nickel
Nicotine and salts
Nitroaniline, 2-
Nitroaniline, 3-
Nitroaniline, 4-
Nitrobenzene
Nitrogen mustard
Nitrogen mustard hydro-
chloride salt.
Nitrogen mustard N-Oxide ....
Nitrogen mustard N-Oxide,
HCI salt.
Nitroglycerine
Nitro-o-toluidine, 5-
Nitrophenol, 2-
Nitrophenol, 4-
Nitropropane, 2-
Nitroquinoline-1 -oxide, 4-
Nitrosodiethylamine
Nitrosodimethylamine
Nitrosodi-n-butylamine
Nitrosomethylethylamine
M-Nitrosodiethanolamine
N-Nitrosodi-n-propylamine ....
N-Nitrosodiphenylamine
N-Nitrosomethyl vinyl amine .
N-Nitrosomorpholine .. .
N-Nitroso-N-ethylurea
N-Nitroso-N-methylurea
WW totals (mg/l)
Multipath
modeled
exit level
180000
78.6
0.0000264
907000
125
0.0708
6.73
0.37
0.0959
141
10.3
69900
0.662
9.880E-06
11700
0.376
121000
385
5040
0.345
0.00019
0.6000406
0.000268
0.000279
0.129
0.0644
7.54
Ground-
water
modeled
exit level
39
0.531
0.00022
30
0.296
0.0156
78
3.12
78
7.8
28.2
78
0.0117
2.32
0.039
1.83
14
10.5
0.084
3.180E-06
0.0000106
0.000122
0.0000212
0.000053
0.2
Extrapo-
lated exit
level
0.023
0.0069415
14.7
0.159
14.7
0.159
0.159
14.7
011775
0.159
0.0069415
7.8
0159
0.11775
0.00285
0.159
0 02762
0 159
011775
14.7
14.7
0.11775
0.159
0.159
0.159
0.02762
0.02762
0.02762
0.159
0.159
0.159
0.159
0.159
0.02762
0.0252
0.0252
0.159
0.0000371
0.0000371
0.159
0.159
0.159
WWEQC
0.005
0.011
0.02
0.01
0.01
0.016
0.01
0.05
0.1
0.00009
0.009
0.021
0.1
0.05
0.000086
0.00011
0.00013
0.01
0.00083
0.005
0.01
0.01
0.01
0.01
0.00024
0.00026
0.001
0.0018
0.01
0.01
0.01
0.005
0.02
0.05
0.05
0.02
0.0064
0.01
0.01
0.05
0.00577
0.04
0.002
0.0006
0.06
0.028
0.01
0.026
0.05
0.05
6!6i
NWW totals (mg/kg)
Multipath
modeled
leach level
55200
743
0.000277
568
0.598
8.91
138000
19.4
504
90.8
112000
17000
39500
1.43
0.000128
8400
306
114
120000
106
44.8
0.128
0.00064
0.00245
0.094
• 0.00244
0.0233
1270
Extrapo-
lated leach
level
30.85
0.194
6900
19.955
6900
19.955
19.955
6900
i"66
19.955
0.194
1210
19 955
1.66
3.9
19955
3.28
19955
1.66
6900
6900
' 1.66
19.955
19.955
19.955
3.28
3.28
3.28
19 955
19955
19955
19.955
19955
3.28
2.991
2.991
labss
0.012875
0.012875
19.955
19.955
19.955
NWW
EQC
0.005
0.0035
1
0.0719
0.7
0.097
0.07
0.5
0.1
0.0005
0.46
7
r_
00057
0.02
0.02
0.00834
0.00315
0.0027
0.7
0.7
0.0691
0.046
0.0001
0.02
0.3
0.0665
0.7
0.7
0.7
1
1
3
3
1
0.0544
0.7
0.7
3
0.0022
3
1
0.074
0.03
0.016
0.7
0.0144
0.0846
3
6^7
NWW leach (mg/l)
Ground-
water
modeled
each level
15
0.162
0.000032
11.6
0.138
0.006
30
0.92
30
0
8.1
23.4
1 .41 OE-06
0.19
0.015
1.83
2.7
4.89
0.032
1.020E-06
3.400E-06
0.000036
6.800E-06
0.000017
0.046
Extrapo-
lated each
level
0.015
0.48
10.5
0 105
10.5
0.105
0.105
10.5
6A
0.105
0.48
6.2
0.105
6.4
0.0000661
0.105
0.00884
0 105
6.4
10.5
10.5
6.4
0.105
0.105
0.105
0.00884
0.00884
0.00884
0 105
0.105
0 105
0.105
0 105
0.00884
0.0083
0.0083
0.105
0.0000119
0.0000119
0.105
0.105
0.105
WW EQC
0.005
0.011
0.02
0.01
0.01
0.016
0.01
0.05
0.1
0.00009
0.009
0.021
0.1
0.05
0.000086
0.0001 1
0.00013
0.01
0.00083
0.005
0.01
0.01
0.01
0.01
0.00024
0.00026
0.001
0.0018
0.01
0.01
0.01
0.005
' 0.02
0.05
0.05
0.02
0.0064
0.01
0.01
0.05
0.00577
0.04
0.002
0.0006
0.06
0.028
0.01
0.026
0.05
0.05
0.01
-------
Federal Register / Vol. 60, No. 245 /Thursday, December 21, 1995 / Proposed Rules 66431
TABLE C-1.—SUMMARY OF CONSTITUENT-SPECIFIC EXIT LEVEL DEVELOPMENT USING TOXICITY BENCHMARKS—
Continued
CAS No.
615-53-2 ....
16543-55-8
100-75-4 ....
930-55-2 ....
13256-22-9
103-85-5 ....
1615-80-1 ..
152-16-9 ....
20816-12-0
297-97-2 ....
126-68-1 ....
123-63-7 ....
58-38-2
608-93-5 ....
76-01-7
82-68-8
87-86-5
62-44-2 ......
85-01-8 —
108-95-2 ....
62-38-4 —
25265-76-3
108-45-2 ....
106-50-3 ....
298-02-2
298-06-6 ....
3288-58-2 ..
2953-29-9 ..
85-44-9 —
109-06-8 ....
1336-36-3 ..
23950-58-5
1120-71-4 ..
107-10-8 ....
51-52-5
107-19-7 ...
129-00-0 ...
110-86-1 ...
50-55-5 .....
108-46-3 ...
81-07-2 —
94-59-7
7782-49-2 ..
7440-22-4 ..
18883-66-4
57-24-9 ......
100-42-5 ....
18496-25-8
1746-01-6 ..
95-94-3 .
630-20-6 ....
79-34-5
127-18-4 ....
58-90-2
107-49-3 ....
3689-24-5 ..
7440-28-0 ..
62-55-5
39196-18-4
108-98-5 ....
79-19-6
62-56-6
137-26-8 ....
7440-31-5 .
108-88-3 ....
584-84-9 ....
95-80-7 „....
823-40-5 ....
Name
N-Nitroso-N-melhylurethane .
N-Nitrosopiperidine
N-Nilrosopyrrotidine
N-Nitrososarcosine
N-Phenyithiourea
N N-DiethylihydrazIne
Octamolhyl- pyro-
phosphoramide.
O.O-Dtethyl O-pyrazinyl
phosphorothioate.
O.O.O-Trielhyl
ptiosphorothioate.
Paraldehyde .
Parathion .*.
Penlachlorobenzene
Pentachloronitrobenzene
(PCNB).
Phonanthrene . .
Phenyl mercuric acetate
Phenylenediamines (N.O.S.)
Phenylenediamine, m-
Phenylenediamine p-
Phosphorodithiofc acid, o-o-
dielhyl ester.
Phosphofodithioic acid, o-o-
dielhyl-s-methyl.
Phosphorodithioic acid,
trimethyl ester.
Phthalfc anhydride
Picoline 2- .
Porychlorinated biphenyls
Pronamide
Propylamlne, n-
Propylthiouracil
Pvrone
Pvridine
Reserpine
Resorcinol
Saccharin and salts
Safrols
Selenium
Silver .... . .
Strychnine
Styrene
Sullide
TCDD, 2,3 7,8-
Tetrachlorobenzene, 1,2,4,5-
Tetrachloroethane, 1,1,1,2- ...
TelracMoroethane, 1,1,2,2- ...
TetracWoroethylene
Telracbtorophenol, 2,3,4,6- ...
Tetraethyl pyrophosphate
Tetraethyldithiopyrophosphat-
e.
Thallium (I)
Thioacetamide
Thiofanox
Thiophenot
Thiosemicarbazide
Thiourea
Thiram
Tin
Toluene
Toluene diisocyanate
Toluonediamine, 2,4-
Tduenedlamine. 2.6-
WW totals (mg/l)
Multipath
modeled
exit level
0.0106
0.101
7310
2.63
7.86
13.9
0.301
19300
0.506
5440
0.106
0.000286
80.3
3040
0.522
0.0829
822
199
3.34
75.7
1.050E-09
14.8
0.0241
0.0037
15600
2720
0.23
646
29.8
0.211
Ground-
water
modeled
exit level
0.0000106
0.000212
0.273
440000
5.15
0.081
0.00204
84
0.0117
0.78
0.00614
21.3
54.1
0.156
0.0035
0.927
0.045
63.7
1.880E-07
0.234
0.075
0.024
2.04
1.89
0.05
41.3
0.000159
Extrapo-
lated exit
level
0 159
0.159
0.159
0 11775
0.159
1.24
0.11775
0.11775
7.8
0.023
14.7
0.00285
0.159
0.159
0.11775
0.11775
0 11775
132
0.159
011775
0.159
0.11775
39
0.159
0.0069415
0.159
14.7
0
14.7
0.159
0.11775
0.11775
0.11775
0.11775
0.0069415
1.24
0.159
0.159
WWEQC
0.00135
0.0047
0.0053
3
0.02
0.05
1
0.0005
0.000038
0.005
0.02
0.00008
0.02
0.006
0.00028
0.01
0.0174
0.01
0.00004
0.001
0.0005
0.00145
0.005
0.1
0.01
0.00027
0.011
0.05
0.1
0.0021
0.0006
0.0005
0.0084
0.00004
2
1.000E-08
0.00141
0.00005
0.0002
0.00014
0.00062
0.000058
0.0007
'1
0.05
0.02
0.05
8
0.0001 1
0.0134
0.02
NWW totals (mg/kg)
Multipath
modeled
leach level
0.00247
0.0534
31
0.128
205
11.4
2.92
163000
0 00932
784
157
0.00596
438
15800
814
10.5
1.94
0.134
0.0041
629000
7.980E-06
•168
133
29.3
13300
6150
2.81
5.12
176000
. 0.0101
Extrapo-
lated leach
level
19955
19955
19.955
1.66
19.955
8.72
1.66
1.66
1210
30.85
6900
3.9
19.955
19.955
1.66
1.66
1.66
2352.5
19.955
«
1.66
19.955
1.66
36700
19.955
0.194
19.955
6900
0
6900
19.955
1.66
1.66
1.66
1.66
0.194
,8.72
19,955
19.955
NWW
EQC
0.033
0.042
0.146
• 200
1
3
70
0.025
0.02
0.01
0.052
0.1222
1
0.7
0.2185
0.7
0.7
0.7
0002
7.
0.07
0.04
0.097
0.005
7
0.05
0.0726
0.2
3
7
0.015
5
0.3
3
0.004
2
1.000E-06
0.034
0.0001
0.0002
0.0007
0.04
3
0.0039
3
3
1
3
500
0.0002
7
1
1
NWW leach (mg/l)
Ground-
water
modeled
each level
3.400E-06
0.000068
0.105
11600
0.0543
0.0054
0.00041
32
0.0045
0.3
4.810E-06
5.7
1.69
0.06
0.00095
0.357
0.016
15.4
1.780E-10
0.0317
0.0078
0.0077
0.68
0.58
0.0192
12.6
0.000051
Extrapo-
lated each
level
0 105
0.105
0.105
6.4
0.105
0.4165
6.4
6.4
6.2
0.015
10.5
0.0000661
0.105
0.105
•6.4
6.4
6.4
27.6
0.105
6.4
0.105
6.4
15
0.105
0.48
0.105
10.5
0
10.5
0.105
6.4
6.4
6.4
6.4
0.48
0.4165
0.105
0.105
WWEQC
0.00135
0.0047
0.0053
3
0.02
0.05
1
0.0005
0.000038
0.005
0.02
0.00008
0.02
0.006
0.00028
0.01
0.0174
0.01
0.00004
0.001
0.0005
0.00145
0.005
0.1
0.01
'0.00027
0.011
0.05
0.1
0.0021
.-0.0006
0.0005
0.0084
0.00004
2
1.000E-08
0.00141
-'0.00005
• 0.0002
0.00014
0.00062
0.000058
'0.0007
1
' • " 0.05
: -:•' -'0.02
.1 0.05
: - " • 8
,-:o.oooi 1
, '-0.0134
0.02
-------
66432 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
TABLE C-1 .—SUMMARY OF CONSTITUENT-SPECIFIC EXIT LEVEL DEVELOPMENT USING TOXICITY BENCHMARKS—
• Continued
CAS No.
496-72-0 ....
636-21-5 ....
95-53-4
106-49-0 ....
8001-35-2 ..
76-13-1
120-82-1 ....
71-55-6
79-00-5
79-01-6
75-69-4
75-70-7 ......
95-95-4
88-06-2
93-76-5
93-72-1
96-18-4
99-35-4
126-72-7 ....
52-24-4 ......
72-57-1
66-75-1
7440-62-2 ..
108-05-4 ....
75-01-4 ......
81-81-2
1330-20-7 ..
7440-66-6 ..
Name
Toluenediamine, 3,4-
Toluidine hydrochloride, o- ...
Toluidine, o-
Toluidine, p-
Toxaphene
Trichloro-1,2,2-
trifluoroethane, 1,1,2-.
Trichlorobenzene, 1,2,4-
Trichloroethane, 1,1,1-
Trichloroethane, 1,1,2-
Trichloroethylene
Trichlorofluoromethane
Trichloromethanethiol
Trichlorophenol, 2,4,5-
Trichlorophenol, 2,4,6-
Trichlorophenoxyacetic acid,
2,4,5- (245-T).
Trichlorophenoxypropionic
acid, 2,4,5- (Silvex).
Trichloropropane, 1,2,3-
Trinitrobenzene, sym-
Tris (2,3-dibromopropyl)
phosphate.
Tris (1-azridinyl) phosphine
sulfide.
Trypan blue
Uracil mustard
Vanadium
Vinyl acetate
Vinyl chloride
Warfarin
Xylenes (total)
Zinc
, WW totals (mg/l) .
Multipath
modeled
exit level
0.441
0.703
0.000364
2210
0.685
73.9
0.0117
138
51.4
38.8
0.1
15.5
9.72
707
3
0.000237
15800
0.00199
22.4
23200
Ground-
water
modeled
exit level
0.00224
0.00224
21.5
11000
9.31
120
0.007
0.0384
48
18.1
0.0536
1.68
1.26
1.1
0.0078
0.00252
9.58
0.000156
859
99
Extrapo-
lated exit
level
0.159
0.159
0 11775
0.11775
14.7
0 159
14.7
0.0069415
WW EQC
0.02
0.01
0.0121
0.0168
0.00127
0.00108
0.0002
0.00008
0.0001
0.00019
0.00008
0.00049
0.0004
0.00008
0.00008
0.00032
0.00026
0.0245
0.003
0.005
0.00017
0.05
0.002
0.002
NWW totals (mg/kg)
Multipath
modeled
leach level
2.35
0.128
0.000176
3450
48200
11.3
567
25800
11500
124
63.2
6.36
872
0.442
0.357
250
1.23
172000
316
Extrapo-
lated leach
level
19.955
19.955
1.66
1.66
6900
19 955
6900
0.194
NWW
EQC
1
0.7
0.029
0.043
0.0295
0.00114
0.574
0.0002
0.004
0.0001
0.001
0.0672
0.0785
0.0063
0.00028
0.0009
0.25
0.061
1
0.005
0.0017
3
0.0002
0.3
NWW leach (mg/l)
Ground-
water
modeled
each level
0.00068
0.00068
0.11
2400
1.3
0.0539
0.0018
0.0128
16
4.2
0.0152
0.64
0.48
0.34
0.003
0.000099
3.71
0.00006
147
38.4
Extrapo-
lated each
level
0.105
0.105
6.4
6.4
10.5
0.105
10.5
0.48
WWEQC
0.02
0.01
0.0121
0.0168
0.00127
0.00108
0.0002
0.00008
0.0001
0.00019
0.00008
0.00049
0.0004
0.00008
0.00008
0.00032
0.00026
0.0245
0.003
0.005
0.00017
0.05
0.002
0.002
TABLE C-2.—SUMMARY OF CONSTITUENT-SPECIFIC EXIT LEVEL DEVELOPMENT USING MCL-BASED NUMBERS
CAS No.
83-32-9
208-96-8 ....
67-64-1
75-05-8
98-86-2
75-36-5
591-08-2 ....
53-96-3 ..:...
107-02-8 ....
79-06-1
107-13-1 ....
1402-68-2 ..
116-416-3 ....
309-00-2 ....
107-18-6 ....
107-05-1 ....
92-67r1 ..:...
2763-96-4, ..
504-24-5 ....
61-82-5 ......
62-53-3
120-12-7 :...
7440-36-0 ..
140-57-8 ....
7440-38r-2 ..
2465-27-2 ..
115-02-6 ....
7440r-39-3' ..
71-43-2 ......
92-87-5
Name
Acenaphthene
Acenaphthylene
Acetone
Acetonitrile
Acetophenone
Acetyl chloride
Acetyl-2-thiourea, 1-
Acetylaminofluorene, 2-
Acrolein
Acrylamide
Acrylonitrile
Aflatoxins
Aldicarb
Aldrin
Allyl alcohol
Allyl chloride ::...
Aminobiphenyl, 4-
Aminomethyl-3-isoxazolol,
5-. : ' .
Aminopyridine, 4-
Amitrole
Aniline
Anthracene
Antimony
Aramite ,
Arsenic
Auramine
Azaserine
Barium
Benzene
Benzidine
WW totals (mg/l)
Multipath
modeled
exit level
49.5
232000
6.58
5960
0.00248
3.67
0.00428
5.640E-07
0.0742
0.444
8210
40.5
0.0209
0.00015
Ground-
water mod-
eled exit
level '
31.2
15.6
0.78
16.8
0.00026
0.0011
0.00469
0.053
0.136
0.384
28
0.0295
2.2400E-06
Extrapo-
lated exit
level
0.00285
00241
0.11775
0.02762
14.7
0.0069415
39
'.. 0.02762
0.159
0.02762
0.0069415
. 0.00285
14.7
0.159
0.159
WWEQC
0.0018
0.02
0.2
0.015
0.00158
1
0.02
0.013
0.01
0.008
0.05
0.000034
0.002
0.02
0.00023
0.007
0.0008
0:02
. 0.0005
0.001
0.0,0004
0.0025
NWW totals (mg/kg)
Multipath
modeled
exit level
9480
17400
923
1210
2.63
0.00436
0.961
0.000444
258
4.21
8.72
0.17
2080
.109
0.0000298
Extrapo-
lated exit
level
3.9
30.85
1.66
3.28
6900
0.194
36700
3.28
19.955
3.28
, 0 194
3.9
6900
19.955
19.955
NWW
EQC
0.0742
0.7
0.027
0.014
0.03
70
1
0.075
0.1
0.7
1
0.0006
0 002
1
0.0132
0.5
2
1
0.3031
6.2
0.0001
0.042
NWW leach (mg/l)
Ground-
water
modeled
Leach
level
4.9
6
0.3
6.4
0.000038
0.00034
3.670E-06
0.017
0.053
0.15
10.8
0.009
6.800E-07
Extrapo-
lated
Leach
level
0.00119
0.0115
6.4
0.00884
10.5
0.54
15
'0.00884
0 105
0.00884
0.54
0.00119
10.5
0.105
• 0.105
WWEQC
0.0018
0.02
0.2
0.015
0.00158
1
0.02
0.013
0.01
' 0.008
0.05
0.000034
0.002
0.02
0.00023
0.007
0.0008
0.02
0.0005
0.001
0.00004
0.0025
-------
Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66433
TABLE C-2.—SUMMARY OF CONSTITUENT-SPECIFIC EXIT LEVEL DEVELOPMENT USING MCL-BASED NUMBERS—
Continued
CAS No.
106-51-4 ....
98-07-7 ......
50-32-8
205-99-2 ....
205-82-3 ....
207-08-9 ....
191-24-2 ....
100-51-6 ....
100-44-7 ....
225-51-4 ....
7440-41-7 ..
39638-32-9
111-44-4 ....
117-81-7 ....
542-86-1 ....
598-31-2 „..
75-27-4 ......
75-25-2
101-55-3 ....
357-57-3 ....
71-36-3 ......
88-85-7 ......
85-68-7
7440-43-9 ..
85-74-8
75-15-0
353-50-4 ....
55-23-5 . —
75-87-6
305-03-3 ....
57-74-9
494-03-1 ....
125-99-8 „..
107-20-0 ....
105-47-8 ....
108-90-7 ....
510-15-6 ....
124-48-1 ....
75-00-3
110-75-8 ....
87-66-3
59-50-7
107-30-2 ....
91-58-7 ......
95-57-8 —
7005-72-3 ..
5344-82-1 ..
542-76-7 ....
7440-47-3 ..
218-01-9 ....
6358-53-8 ..
7440-48-4 ..
7440-50-8 ..
108-39-4 ....
95-48-7 ......
105-44-5 ....
4170-30-3 ..
57-12-5
14901-08-7
108-94-1 ....
131-89-5 ....
50-18-0
20830-81-3
72-54-8
53-19-0
72-65-9
3424-82-6 ..
Name
Bis (2-ctilorolsopropIy) ether
Bis(2-chtor6thyl)eth6r
Bis(2-elhylhexyl)phtha!ate ...
Bromoform
(Trlbromom ethane).
Bromopheynl phenyl ether,
4-.
Butsnol
ButyM.G-cfinitropheno!, 2-
sec- (Dinoseb).
Carbon tetrachlorfde
Chtorat
Chtoro-1,3-butadiene, 2-
(Chloroprene).
Chtorodibromomethane
Chtoroelhane (ethyl chlo-
ride).
Chtofomelhyl methyl ether .
Chkxophenyl phenyl ether,
4-.
Chkxophenyl thiourea, 1-o-
Citrus red No 2
Cobalt
Cyctohexyl-4,6-
dinitrophenol, 2-.
ODD
nnn fn rt\
DDE
DDE (o o'l
WW totals (mg/l)
Multipath
modeled
exit level
0.00231
0.000805
22500
1.13
0.0138
10.1
0.569
0.00141
0.00044
33.3
0.178
38600
15.4
235
1600
0.738
0.0115
0.000014
0.515
517
1.5
0.0731
16.3
0.00759
134
1300
1.32
674
615
656
63.5
0.000126
9.110E-06
Ground-
water mod-
eled exit
level
1.88
0.0164
39
3 9
0.000717
0.000827
0.007
0.000648
1260
0.00854
0.064
15.6
0.0336
437
0.038
18.4
0.1
24
0.42
0.68
0.054
0.0066
0.057
0.9
0.618
0.1
2790
8.4
8.4
0.84
913000
0.228
Extrapo-
lated exit
level
14.7
0.27
0.00285
0.00285
0.00285
0.00285
0.0241
0.0241
0.0241
0.159
0.159
0.0241
0.27
0.27
0.27
0 0241
0.0241
0.27
a27
0.0241
0.27
, 0.0241
0.0241
0.27
14.7
0.618
7.8
0.159
14.7
7.8
0.0252
0.159
14.7
0.0069415
-------
66434 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
TABLE C-2.—SUMMARY OF CONSTITUENT-SPECIFIC EXIT LEVEL DEVELOPMENT USING MCL-BASED NUMBERS—
Continued
CAS No.
50-29-3
789-02-6 ....
2303-16-4 ..
132-64-9 ....
192-65-4 ....
189-64-0 ....
189-55-9 ....
194-59-2 ....
226-36-8 ....
53-70-3
224-42-0 ....
96-12-8
864-41-0 ....
110-57-6 ....
96-23-1
95-50-1
541-73-1 ....
106-46-7 ....
91-94-1
75-71-8
75-34-3
107-06-2 ....
75-35-4
156-59-2 ....
156-60-5 ....
111-91-1 ....
98-87-3
120-83-2 ....
87-65-0
94-75-7
78-87-5 ......
542-75-6 ....
10061-91-5
10061-02-6
60-57-1
1464-53-5 ..
84-66-2
311^15-5 :...
56-53-1
94-58-6 .:....
60-51-5
131-11-3 ....
77-78-1 ......
60-11-7 ....:.
119-93-7 ....
57-97-6
79-44-7 ......
122-09-8 .'...
105-67-9 ...'.
119-90-4 ....
84-74-2
99-6^-0 ......
100-25H1 .'...
534-52-1 ....
51-28-5 ...'.;
121-14-2 .'.'.I'
606-20-2 i.:
H7-84-0 :...•
123-91-1 !;.:
122-39-4 ....
122-66^7 •.>:':;•
298-04-4' i.:
541-53-7 L;
1 15-29-7- V.'..'
959-98^8 .':...
33213-65^-9""
Name , '
DDT
DDT (o,p')
Diallate
Dibenzofuran
Dibenzo[a,e]pyrene
Dibenzo[a,h]pyrene
Dibenzo[a,i]pyrene
Dibenzo[c,g]carbazole, 7H- .
Dibenz(a,h)acridine
Dibenz(a,h)anthracene
Dibenz[a,j]acridine
Dibromo-3-chloropropane,
1,2-.
Dichloro-2-butene, 1,4-
Dichloro-2-butene, trans-
1,4-.
Diohloro-2-propano), 1,3- ....
Dichlorobenzene, 1 ,2-
Dichlorobenzene, 1,3-
Dichlorobenzene, 1,4-
Diohlorobenzidine, 3,3'-
Dichlorodiflouromethane
Dichloroethane, 1,1-
Diohloroethane, 1,2-
Dichloroethylene, 1,1-
Dichloroethylene, cis-1 ,2- ...
Dichloroethylene, trans-1 ,2-
Dichloromethoxyethane
Dichloromethylbenezene
(benzal chloride).
Dichlorophenol, 2,4-
Dichlorophenol, 2,6-
Dichlorophenoxyacetic acid,
2,4- (2,4-D).
Dichloropropane, 1,2-
Dichloropropene, 1,3-.
Dichloropropene, cis-1 ,3- ....
Dichloropropene, trans-1 ,3-
Dieldrin
Diepoxybutane, 1,2,3,4-
(2,2'-bioxirane.
Diethl phthalate
Diethyl-p-nitrophenyl phos-
phate.
Diethylstillbestrol
Dihydrosafrole
Dimethoate
Dimethyl phthalate
Dimethyl sulfate
Dimethylaminoazobenzene,
P--
Dimethylbenzidine, 3,3'-
Dimethylbenz(a)anthracene,
7,12-.
Dimethylcarbamoyl chloride
Dimethylphenethylamine,
alpha, alpha-.
Dimethylphenol,2,4-
Dimethyloxybenzidine,3,3'- .
Di-n-butyl phthalate ...1.
Dinitrobenzene,1 ,3-
Dinitrobenzene,1,4-
Dinitro-o-cresol,4,6-
Dinitrophenol,2,4-
Dinitrotoluene,2,4- ..:
Dinitroto!uene,2,6- .'.
Di-n-octyl phthalate
Dioxane,1 ,4-
Diphenylamine
Diphenylhydrazine,1,2- .:
Disulfoton ..„
Dithiobiuret '..'...':.:;.....
Endosulfan
Endosulfan I '..:'„;.....•...
Endosulfan II
Multipath
modeled
exit level
0.000018
0.26
8.440E^06
0.0723
15.4
3.01
0.0037
14.7
37.4
0.00698
0.00345
30000
44200
6.94
58.5
0.303
0.00476
0.00485
0.0049
0.000059
3560
7.710E-07
38.1
"200000
0.000625
3.820E-06
151
1.78
883
1.28
50.2
10.7
12.9
. 0.002
558
.. 29
0.0131
6.62
WW totals (mg/l)
Ground-
water mod-
eled exit
level
20.4
90.1
0.00176
' o"bb'22
7.8
1.12
0.0042
35.7
0.00016
0.0475
0.0413
0.294
0.42
0.62
0.273
• 0.115
0.0028
90000
90000
682
186
4.2900E-07
29.4
78
0.0000702
0.00464
3.78
0.0336
900
0.0168
0.273
0.294
0.168
1260
0.0424
14.7
. 458
6
Extrapo-
lated exit
level
00069415
84
0.00285
0.00285
0.00285
0.00285
0.00285
0.00285
0.0241
0.0241
0.27
0.0241
0.0241
0.0241
0.0241
14.7
0.159
14.7
0.11775
0.02762
, 0.27
0.159
0.0252
. 0.0252
0.159
0.11775
0.0069415
0.0069415
WWEQC
0.00008
0.0006
0.0
0.00
0.0002
0.0002
0.0
0.0002
0.00003
0.00
0.00026
0.005
0.005
0.01
0.00003
0.005
0.00004
0.0024
0.0001
0.00004
0.00006
0.00012
000012
0.00006
0.01
0.005
0.00041
0.01
0.00029
0.00004
0.0009
0.00069
0.00094
0.000044
0.005
0.00025
0.0078
0.05
0.00029
0.00064
0.01
0.0033
0.00037
0.05
0.00047
0.0077
0.00033
0.00011
0.04
0.05
0.00042
0.00002
0.00031
0.000042
0.012
0.00151
. 0.01
0.00007
0.00004
0.0003
0.0004
NWW totals (mg/kg)
Multipath
modeled
exit level
0.00315
1.2
abbbiss
. 0.663
50000
63.9
0.0524
8070
24.2
6.1
2.55
5400
13800
769
3140
16.9
32.4
2.64
2.67
0.00176
4490
2.470E-1 1
1.6
0.00062
0.00263
11300
0.236
90000
. 5.54
56.1
213
86.3
4480
13.2
11800
. 42.6
73.1
Extrapo-
lated exit
level
0.194
27400
3.9
3.9
3.9
3.9
3.9
3.9
30.85
30.85
142
30.85
30.85
30.85
30.85
6900
19.955
, 6900
1.66
3.28
142
19.955
2.991
2.991
19.955
1.66
0.194
0.194
NWW
EQC
0.0006
0.023
0.7
0.7
0.0
0.0
0.7
0.01
0.084
0.7
0.0003
0.005
0.005
0.05
0.0002
0 7
0.0001
0.116
0.0052
0.0002
0.0001
0.0014
0.02
0.0006
0 7
0 3
0.0788
0.7
0.0001 1
0.0001
0.0003
0.0003
0.0003
0.0006
0.005
0.022
1
0.0691
0.013
0.7
0.7
0.039
3
0.052
7
0.249
0.25
3
3
0.03
0.26
0.25
0.139
0.0005
0.041
0.7
0.0035
0.0005
0.009
0.003
NWW leach (mg/l)
Ground-
water
modeled
Leach
level
0.005
0.4
6 340 E-0"
0.00038
1.62
0.216
0.00072
11.9
0.00006
0.009
0.0216
0.112
0.16
0.18
0.105
0.0115
0.00085
1150
1150
0.54
54
6.500E-08
0.77
30
0.000018
2 760E-06
1.19
0.0102
100
0.0064
0.105
0.112
0.064
0.1
0.0136
2.6
13
• 0.94
Extrapo-
lated
Leach
level
0.54
1.8
0.00119
0.00119
0.00119
0.00119
0.00119
0.00119
0.0115
0.0115
0.033
0.0115
0.0115
0.0115
0.0115
10.5
0.105
10.5
6.4
0.00884
0.033
0.105
0.0083
0.0083
0.105
6.4
0.54
0.54
WWEQC
0.000081
0.00063
0.01
0.001
0.0002
0.0002
0.01
0.0002
0.00003
0.001
0.00026
0.005
0.005
0.01
0.00003
0.005
0.00004
0.0024
0.0001 .
0.00004
0.00006
0.00012
0.00012
0.00006
0.01
0.005
0.00041
0.01
0.00029
0.00004
0.0009
0.00069
0.00094
0.000044
0.005
0.00025
0,0078
0.05
0.00029
0.00064
60
0.01
0.0033
0.00037
0.05
0.00047
0.0077
0.00033
0.0001 1
0.04
0.00
0.00042
0.00002
0.00031
0.000042
0.012
0.00151
0.01
0.00007
0.00004
0.0003
0.0004
-------
Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66435
TABLE C-2.—SUMMARY OF CONSTITUENT-SPECIFIC EXIT LEVEL DEVELOPMENT USING MCL-BASED NUMBERS—
Continued
CAS No.
1031-07-8 ..
145-73-3 ....
72-20-8
7421-93-4 ..
63494-70-5
106-89-8 ....
S1-43-4 ......
110-80-5 ....
141-78-6 ....
51-79-6
107-12-0 ...
60-29-7 .....
97-63-2
62-50-0 .....
100-41-4 ...
106-93-4 ...
75-21-8 —
96-45-7 ......
151-66-4 ....
52-85-7
640-19-7 ....
62-74-8 —
206-44-0 ....
86-73-7 ......
18984-48-8
50-00-0
64-18-6
765-34-4 ....
319-86-8 ....
76-44-8
1024-57-3 ..
87-68-3 ......
118-74-1 ....
319-84-6 ....
319-85-7 ....
58-89-9 ......
77-47-4
70-30-4
1888-71-7 ..
757-58-4 ....
591-78-6 ....
302-01-2 ....
193-39-5 ....
74-88-4 . —
78-83-1
465-73-6 ....
78-59-1
120-58-1 ....
143-50-0 ....
303-43-4 ....
7439-92-1 ..
108-31-6 ....
123-33-1 ....
109-77-3 ....
148-82-3 ....
7439-97-6 ..
126-98-7 ....
74-93-1 . —
67-56-1
91-80-5 ......
16752-77-5
72-43-5
74-83-9
74-87-3
78-93-3 ......
1338-23-4 „
6O-34-4 .
Name
Endrin aldehyde
Ethyl cyanWe (propionitrite)
Pfhul Alhar
Ethyl methanesulfonate —
Fluoracelfc add, sodium
salt.
Fluoride
Formic Add
HCH, delta-
Heptachlor
Hoxachlorol,3-butadiene ...
Hexachlorocyclohexane,
alpha- (alpha-BHC).
Hexachlorocyclohexane,
beta- (beta-BHC).
Hexachlorocyclohexane,
gamma- (Llndane).
HexacMorocyctopentadiene
lnderto(1,2,3-cd} pyrene
lonHrtn
Isophorone
Lead ~
Male'rC anhydride
Mitnfr* hwtrj*7lriff
Methyl bromide
(Bronxxnelhane).
Methyl chloride
(Chlocomethane).
Methyl ethyl ketone perox-
ide.
Methyl hvdrazine
WW totals (mg/l)
Multipath
modeled
exit level
0.0729
0.335
14.7
25500
0.0055
74.5
0.000928
17.7
1580
1310
0.0158
'b"booo237
0.000528
0.00788
0.000424
0.000142
0.000445
0.000783
0.00521
0.049
5.150E-06
0.00285
180000
78.6
0.0000264
907000
125
0.0708
6.73
0.37
0.0959
141
Ground-
water mod-
eled exit
level
4800
414000
39
390
390
27.3
24
930000
8.4
0.018
0.00053
27.5
22.4
27.3
273
17400
0.0806
3.6
21
0.0013
340
0.212
0.0521
0.0165
39
0.531
0.00022
30
0.0596
0.1056
78
3.12
78
Extrapo-
lated exit
level
0.0069415
0.0069415
0.0069415
0.0069415
0 159
14.7
0.159
14.7
0 159
0.0069415
0 0241
0.0069415
0
7.8
0.0069415
0.27
14.7
7.8
0.159
0.0241
0.0069415
14.;
b"l59
14.7
0.159
0.159
147
0 11775
0.159
0.0069415
• 78
0.159
WWEQC
0.0004
0.1
0.00039
0.0005
0.0005
0.06519
1.16
' 0.009
0.05
0.1
0.00153
0.00345
0.00106
0.00006
0.00006
0.001
0.02
0.00021
0.00021
0.05
0.0232
0.2
0.0002
0.00004
0.000032
0.0001
0.00161
0.000035
0.000023
0.000025
0.00018
1 .600E-06
0.207
0.01
0.005
0 000043
0.005
0.011
0.02
0.01
0.01
. 0.016
0.01
0.05
0.1
0.00009
0.009
0.021
0.1
0.05
0.000086
0.0001 1
0.00013
0.01
NWW totals (mg/kg)
Multipath
modeled
exit level
0.26
44
6900
272000
41200
3420
0.00133
550000
0.00745
0.51
5970
89800
48.8
301000
7.79
0.0264
36.4
0.0116
0.0333
0.12
0.102
1450
80.6
0.0000241
3.9
55200
743
0.000277
568
0.598
8.91
138000
19.4
• 504
90.8
112000
Extrapo-
lated exit
level
0.194
0.194
0.194
0.194
19.955
6900
19.955
6900
19.955
0.194
30.85
0 194
0
1210
0.194
142
6900
1210
19.955
30.85
0.194
6900
i'b'ibsb
19.955
19.955
6900
"""""T.66
19.955
0.194
1210
19.955
NWW
EQC
0.04
0.0036
0.02
0.03
0.0714
2.03
0.18
3
0.1
0.00319
0.0011
0.018
0.0002
0.0001
0.07
1
0.084
0.08
4
10
0.0006
0.0008
0.0006
0.046
0.0723
0.0008
0.0006
0.002
0.092
0.0206
1.87
0.7
0.005
0.3
0.0748
0.005
0.0035
1
0.0719
O.t
0.097
0.07
0.5
0.1
0.0005
0.46
/
0.005;
0.02
0.02
0.00834
NWW leach (mg/l)
Ground-
water
modeled
Leach
level
24
5400
15
114
10.5
6.6
11700
1.75
0.00075
0.00017
1.74
3.4
10.5
105
66
0.00691
0.018
0.11
0.00021
1.98
0.033
0.00136
0.0000241
15
0.162
0.000032
12
0.023
0.006
30
0.92
30
Extrapo-
lated
Leach
level
0.54
0.54
0.54
0.54
0.105
10.5
0.105
10.5
0.105
0.54
0.0115
0.54
0
6.2
0.54
0.033
10.5
6.2
0.105
1 0.0115
0.54
ib.5
0.105
•me
0.105
0.105
10.5
6.4
0.105
0.54
6.2
0.105
WWEQC
0.0004
0.1
0.00039
0.0005
0.0005
0.06519
1.16
0.009
0.05
0.1
0.00153
0.00345
0.00106
0.00006
0.00006
0.001
0.02
0.00021
0.00021
0.05
0.0232
0.2
0.0002
0.00004
0.000032
0.0001
0.00161
0.000035
0^000023
0.000025
0.00018
1.600E-06
0.207
0.01
0.005
. 0.000043
0.005
'-••• 0.011
• 0.02
• - 0.01 .
0.01
0.016
• :-- 0.01
".-'•. 0.05
0.1
• 0.00009
0.009
. !- .,-
0.021
• ' • : 0.1
. .?-•• 0.05
0.000086
... 0:00011
0.00013
!$'."-• ' ''
• :>'0.01
;"• „ ' f
-------
66436 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
TABLE C-2.—SUMMARY OF CONSTITUENT-SPECIFIC EXIT LEVEL DEVELOPMENT USING MCL-BASED NUMBERS—
Continued
CAS No.
108-10-1 ....
80-62-6
66-27-3
91-57-6
298-00-0 ....
75-55-8
56-49-5
74-95-3
75-09-2
101-14-4 ....
70-25-7
56-04-2
50-07-7
7439-98-7 ..
91-20-3
130-15-4 ....
86-88-4
134-32-7 ....
91-59-8
7440-02-0 ..
54-11-5
88-74-4
99-09-2
100-01-6 ....
98-95-3
55-86-7
51-75-2
126-85-2 ....
302-70-5 ....
55-63-0
99-55-8
88-75-5
100-02-7 ....
79-46-9
56-57-5
55-18-5
62-75-9
924-16-3 ....
10595-95-6
1116-54-7 ..
621-64-7 ....
86-30-6
4549-40-0 ..
59-89-2
759-73-9 ....
684-93-5 ....
615-53-2 ..;.
16543-55-8
100-75-4 ....
930-55-2 ....
13256-22-9
103-85-5 ....
1615-80-1 ..
152-16-9 ....
20816-12-0
297-97-2 ....
126-68-1 ,.,.
123-63-7 ...!
56-38-2 ......
608-93-5 ....
76-OW ...'...
82-68-8 ..„„
87-86-5 ...:..
62-44-2 ...„.
85-01-8 ...;.;
108-95-2 .1..
62-38-4 ...;..-
Name
Methyl isobutyl ketone
Methyl methacrylate
Methyl methanesulfonate ....
Methyl naphthalene, 2-
Methyl parathion
Methylazinidine, 2-
Methylcholanthrene, 3-
Methylene bromide
Methylene chloride
Methylenegbis, 4,4'-(2-
chloraoniline).
Methyl-nitro-
nitrosoguanidine (MNNG).
Methylthiouracil
Mitomycin C
Molybdenum
Naphthoquinone, 1,4-
Naphthyl-2-thiourea, 1-
Naphthylamine, 1-
Naphthylamine, 2-
Nickel
Nicotine and salts
Nitroaniline, 2-
Nitroaniline, 3-
Nitroaniline, 4-
Nitrobenzene
Nitrogen mustard
Nitrogen mustard hydro-
chloride salt.
Nitrogen mustard N-Oxide ..
Nitrogen mustard N-Oxide,
HCI salt.
Nitroglycerine
Nitro-o-toluidine, 5-
Nitrophenol, 2- '.
Nitrophenol, 4-
Nitropropane, 2-
Nitroquinoline-1 -oxide, 4- ....
Nitrosodiethylamine
Nitrosodlmethylamine
Nitrosodi-n-butylamine
Nitrosomethylethylamine
N-Nirtrosodiethanolamine ...
N-Nitrosodi-n-propylamine ..
N-Nitrosodiphenylamine
N-Nitrosomethyl vinyl amine
N-Nitrosomorpholine '
N-Nitroso-N-ethylurea
N-Nitroso-N-methylurea
N-Nitroso-N-methylurethane
N-Nitrosonornicotine
N-Nitrosopiperidine
N-Nitrosopyrrolidine
N-Nitrososarcosine
N-Phenylthiourea ...:
N,N-Diethylhydrazine
Octamethylpyrophosphora-
mide.
Osmium tetroxide
O,O-Diethyl O-pyrazinyl
phosphorothioate.
O,O,O-Triethyl
phosphorothioate.
Paraldehyde
Parathion
Pentachlorobenzene
Pentachloroethane
Pentachloronitrobenzene
(PCNB).
Pentachlorophenol
Phenacetin
Phenanthrene
Phenol
Phenyl mercuric acetate
WW totals (mg/l)
Multipath
modeled
exit level
10.3
69900
0.662
9.880E-06
11700
0.376
121000
385
5040
0.345
0.00019
0.0000406
0.000268
0.000279
0.129
0.0644
7.54
0.0106
0.101
7310
2.63
7.86
13.9
0.301
19300
. 0,506
Ground-
water mod-
eled exit
level
7.8
28.2
78
0.0117
0.029
0.039
1.83
14
4.38
0.084
3.1800E-06
0.0000106
0.000122
0.000212
0.000053
0.2
0.0000106
• 0.000212
0.273
440000
5.15
0.27
0.00204
84
0.0117
Extrapo-
lated exit
level
0.11775
0.00285
0.159
0.02762
0.159
0.11775
14.7
14.7
0.11775
0.159
0.159
0.159
0.02762
0.02762
0.02762
0,159
0.159
0.159
0.159
0.159
0.02762
0.0252
0.0252
0.159
0.0000371
0.0000371
0.159
0.159
0.159
0.159
0.159
0.159
0.11775
0.159
0.618
0.1175
,0.11775
7.8
0.0241
14.7
0.00285
WWEQC
0.00083
0.005
0.01
0.01
0.01
0.01
0.00024
0.00026
0.001
0.0018
0.01
0.01
0.01
0.005
0.02
0.05
0.05
0.02
0.0064
0.01
0.01
0.05
0.00577
0.04
0.002
0.0006
0.06
0.028
0.01
• 0.026
0.05
0.05
0.01
0.00135
0.0047
0.0053
3
0.02
0,05
1
0.0005
0.000038
0.005
0.02
0.00008
0.02
0.006
0.00028
NWW totals (mg/kg)
Multipath
modeled
exit level
17000
39500
1.43
0.000128
8400
306
114
120000
106
44.8
0.128
0.00064
0.00245
0.094
0.00244
0.0233
1270
0.00247
0.0534
31
0.128
205
11.4
2.92
163000
0.00932
Extrapo-
lated exit
level
1.66
3.9
19.955
3.28
19.955
1.66
6900
6900
1.66
19.995
19.955
19.955
3.28
3.28
3.28
19.955
19.955
19.955
19.955
19.955
3.28
2.991
2.991
19.955
0.012875
001 2875
19.955
19955
19.955
19.955
19 955
19.955
1.66
19955
8.72
1.66
1.66
1210
30.85
6900
3.9
NWW
EQC
0.00315
00027
0.7
0.7
0.691
0.046
0 0001
0.02
0.3
0.0665
0.7
0.7
0.054'
0.7
0.7
0 0022
1
0.074
0.03
0.016
0.7
0.0144
0.0846
3
0.7
0.033
0.042
0.146
200
1
3
70
0.025
0.02
0.01
0.052
0.1222
1
0.7
0.2185
NWW leach (mg/l)
Ground-
water
modeled
Leach
level
8.1
23.4
1.410E-06
0.0085
0.09
1.83
2.7
2.04
0.032
1.020E-06
3.400E-06
0.000036
6.800E-06
0.000017
0.046
3.400E-06
0.000068
0.105
11600
0.0543
0.018
0.00041
32
0.0045
Extrapo-
lated
Leach
level
6.4
0.00119
0.105
0.00884
0.105
6.4
10.5
10.5
6.4
0.105
0.105
0.105
0.00884
0.00884
0.00884
0.105
0.105
0.105
0.105
0.105
0.00884
0.0083
0.0083
0.105
0.0000119
0.0000119
0.105
0 105
0.105
0.105
0.105
6.4
0 105
0.194
64
6.4
6.2
0.0115
10.5
0.00119
WWEQC
0.00083
0.005
0.01
0.01
0.01
0.01
0.00024
0.00026
0.001
0.0018
0.01
0.01
0.01
0.005
0.02
0.05
0.05
0.02
0.0064
0.01
0.01
0.05
0.00577
0.04
0.00262
0.0006
0.06
0.028
0.01
0.026
0.05
0.05
0.01
0.00135
0.0047
0.0053
3
002
0.05
1
0.0005
0.000038
0.005
0.02
0.00008
0.02
0.006
0.00028
-------
Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66437
TABLE C-2.—SUMMARY OF CONSTITUENT-SPECIFIC EXIT LEVEL DEVELOPMENT USING MCL-BASED NUMBERS—
Continued
CAS No.
25265-76-3
108-45-2 ....
106-50-3 ....
298-02-2 ....
298-06-6 ....
3288-58-2 .,
2953-29-9 ..
85-44-9 ......
109-05-8 ....
1336-36-3 ..
23950-58-5
1120-71-4 ..
107-10-8 ....
51-52-5 ......
107-19-7 ....
129-00-0 ..„
110-88-1 ....
50-55-5 —
108-48-3 ....
81-07-2
84-59-7
7782-49-2 ..
7440-22-4 ..
18883-66-4
57-24-9 —
100-42-5 ....
18496-25-8
1746-01-6 ..
95-94-3 ......
630-20-6 ....
79-34-5 ......
127-18-4 ....
58-90-2 ......
107-49-3 ....
3689-24-5 ..
7440-28-0 ..
62-55-5 ......
39196-18-4
108-98-5 ....
79-19-6 ......
62-56-6
137-26-8 ....
7440-31-5
108-88-3 ....
584-84-9 ....
95-80-7 ......
823-40-5 ....
496-72-0 ....
636-21-6 ....
95-53-4
106-49-0 ....
8001-35-2 ..
76-13-1
120-82-1 ....
71-55-6
79-00-5 —
79-01-6 . —
75-69-4
75-70-7
95-95-4 —
88-06-2
93-76-5 ......
93-72-1
96-18-4 — .
99-35-4 ......
126-72-7 ....
Name
Phenylenediamines (N.O.S.)
Phenylenedtamlne, m-
Phosphorodilhioto acid, o-o-
diethyl ester.
Phosphorod'rthiote acid, o-o-
diethyhs-methyl.
Phosphorodithtote acid,
trimethyl ester.
Polychlorinated biphenyls ...
SafroJe
Sulffdd
Tetrachlofobanzene,
1,2,4,5-.
Tetrachlofoethane. 1,1,1,2-.
Tetrachtoroelhane, 1,1,2,2- .
Telrachtorophenol, 2,3,4,6- .
TetraelhyWilhiopyrophos-
phate.
Thfophend
Tin
TotuWine hydrochlorkJe, o- .
Tolukline o-
Trfchtoro-1,2,2-
trifluoroethane, 1,1,2-.
Trichtorobenzene, 1,2,4-
Trichtoroethane. 1,1,1-
Trichtoroethane, 1,1,2-
Trichtorolluoromethane
Trichlorophenol, 2,4,5-
Trichlorophenol, 2,4,6-
Trichtorophenoxyacetic acid,
2,4,5- (245-T).
Trichtorophenoxypropionic
acid, 2.4.5- (Silvex).
Trichlofopropane, 1,2,3-
Trinitrobenzene, sym-
Tris (2,3-dibromopropyl)
phosphate.
WW totals (mg/l)
Multipath
modeled
exit level
5440
0.106
0.000286
80.3
3040
0.522
0.0829
822
199
3.34
75.7
1.050E-09
14.8
0.0241
0.0037
15600
2720
0.23
646
29.8
0.211
0.441
0.703
0.000364
2210
0.685
73.9
0.0117
138
51.4
38.8
0.1
15.5
9.72
707
0.000237
Ground-
water mod-
eled exit
level
0.78
11.5
21.3
54.1
0.156
0.0035
0.232
0.045
0.91
0.00057
0.234
0.075
0.024
0.0255
1.89
0.0353
5.9
0.000159
0.00224
0.00224
1170
0.77
9.31
120
0.035
0.024
48
18.1
0.0536
1.68
0.21
1.1
0.0078
0.00252
Extrapo-
lated exit
level
0.159
0.159
0 11775
0 11775
0 11775
132
0.159
011775
0.159
0.11775
39
0.159
0.0069415
0 159
u'.7
0
14.7
0.159
0.11775
0.11775
0 11775
0.11775
0.0069415
0.618
0.159
b".159
0.159
0.159
0 11775
WWEQC
0.01
0:0174
0.01
0.00004
0.001
0.0005
0.00145
0.005
0.1
0.01
0.00027
0.011
0.05
0.1
0.0021
0.0006
0.0005
0.0084
0.00004
2
1.000E-08
0.00141
0.00005
0.0002
0.00014
0.00062
0.000058
0.0007
1
0.05
0.02
0.05
8
0.0001 1
0.0134
0.02
0.02
0.01
0.0121
0.0168
0.00127
0.00108
0.0002
0.00008
0.0001
0.00019
0.00008
0.00049
0.0004
0.00008
0.00008
0.00032
0.00026
0.0245
NWW totals (mg/kg)
Multipath
modeled
exit level
784
157
0.00596
438
15800
814
10.5
1.94
1.134
0.0041
629000
7.80E-06
168
133
29.3
13300
6150
2.81
5.12
176000
0.0101
2.35
0.128
0.000176
3450
48200
11.3
567
25800
11500
124
63.2
6.36
872
0.442
0.357
Extrapo-
lated exit
level
19.955
19.955
1.66
1.66
1.66
2352.5
19.955
1.66
19.955
1.66
36700
19.955
0.194
19.955
6900
0
6900
19.955
1.66
1.66
1.66
1.66
0.194
8.72
19.955
ibis's
19.955
19.955
1.66
NWW
EQC
0.7
0.7
0.7
0.002
7
0.07
0.04
0.097
0.005
7
0.05
0.0726
0.2
, 3
7
0.015
5
0.3
g
0.004
2
1 .OOOE-06
0.034
0.0001
0.0002
0.0007
0.04
0.0039
1
50C
0.0002
7
1
1
1
0.7
0.029
0.043
0.0295
0.00114
0.0574
0.0002
0.004
0.0001
0.001
0.0672
0.0785
0.0063
0.00028
0.0009
0.25
0.061
NWW leach (mg/l)
Ground-
water
modeled
Leach
level
0.3
0.009
5.7
1.69
0.06
0.00095
0.0892
0.016
0.22
5.400E-07
0.0317
0.0078
0.0077
0.0085
'0.58
0.014
1.8
0.000051
0.00068
0.00068
6.3
0.168
1.3
0.0539
0.009
0.008
16
4.2
0.0152
0.64
0.08
0.34
0.003
0.000099
Extrapo-
lated
Leach
level
0.105
0.105
6.4
6.4
6.4
42
0.105
6.4
0.105
6.4
15
0.105
0.54
0.105
10.5
0
10.5
0.105
6.4
6.4
6.4
6.4
0.54
0.194
0.105
0.105
0.105
0.105
— :
6.4
WWEQC
0.01
0.0174
0.01
0.00004
0.001
0.0005
0.00145
0.005
0.1
0.01
0.00027
0.011
0.05
0.1
0.0021
0.0006
0.0005
0.0084
0.00004
2
1 .OOOE-08
0.00141
0.00005
0.0002
0.00014
0.00062
0.000058
0.0007
1
0.05
0.02
0.05
8
0.0001 1
0.0134
0.02
0.02
0.01
'0.0121
0.0168
0.00127
0.00108
•0.0002
0.00008
'0.0001
0.00019
0.00008
0.00049
0.0004
0.00008
0.00008
0.00032
0.00026
0.0245
-------
66438 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
TABLE C-2.—SUMMARY OF CONSTITUENT-SPECIFIC EXIT LEVEL DEVELOPMENT USING MCL-BASED NUMBERS—
Continued
CAS No.
52-24-4
72-57-1
66-75-1
7440-62-2 ..
108-05-4 ....
75-01-4
81-81-2
1330-20-7 ..
7440-66-6 ..
Name
Tris(l-azridinyl) phosphine
sullide.
Trypan blue
Uracil mustard
Vanadium
Vinyl acetate
Vinyl chloride
Warfarin
Xylenes (total) :
Zinc
Multipath
modeled
exit level
15800
0.00199
22.4
23200
WW totals (mg/l)
Ground-
water mod-
eled exit
level
9.58
0.0078
88
99
Extrapo- '
lated exit
level
0.11775
14.7
0.159
14.7
0.0069415
WWEQC
0.003
0.005
0.00017
0.05
0.002
0.002
NWW totals (mg/kg)
Multipath
modeled
exit level
250
1.23
172000
316
Extrapo-
lated exit
level
1.66
6900
19.955
6900
0.194
NWW
EQC
1
0.005
0.0017
3
0.0002
0.3
NWW leach (mg/l)
Ground-
water
modeled
Leach
level
3.71
0.003
21
38.4
Extrapo-
lated
Leach
level
6.4
10.5
0.105
10.5
0.54
WWEQC
0.003
0.005
0.00017
0.05
0.002
0.002
Appendix D
TABLE D-t .—COMPARISON BETWEEN MODELED EXIT LEVELS AND UNIVERSAL TREATMENT STANDARDS
CAS
83-32-9
67-64-1
75-05-8
98-86-2
107-02-8
107-13-1
107-05-1
62-53-3
7440-36-0
• 7440-38-2
7440-39-3
56-55-3
71^13-2
50-32-8
205-99-2
39638-32-9
111^14-4
117-81-7
75-27-4
75-25-2
71-36-3
88-85-7
85-68-7
7440-43-9
75-15-0
56-23-5
57-74-9
126-99-8
106-47-8
108-90-7
510-15-6
124-48-1
67-66-3
95-57-8
7440—47 3
218-01-9
108-39-4
95-48-7
106-44-5
72-54-8
72-55-9
50-29-3
84-74-2
117-84-0 •
96-12-8
95-50-1
106-46-7
75-71-8
75-34-3
107-06-2
75-35-4
156-60-5
120-83-2
Name
Acenaphthene
Acetone
Acetonitrile
Acetophenone
' Acrolein
Acrylonitrile
Allyl chloride
Aniline
Antimony
Arsenic
Barium
Benz(a)anthracene
Benzene
Benzo(a)pyrene
Benzo(b)fluoranthene
Bis (2-chloroisopropyl) ether
Bis(2-chlorethyl)ether
Bis(2-ethylhexyl)phthalate
Bromodichloromethane
Bromoform (Tribromomethane)
Butanol
Butyl-4,6-dinitrophenol, 2-sec- (Dinoseb)
Butylbenzylphthalate
Cadmium
Carbon disulfide
Carbon tetrachloride
Chlordane
Chloro-1 ,3-butadiene, 2-(Chloroprene)
Chloroaniline, p-
Chlorobenzene .•
Chlorobenzilate
Chlorodibromomethane
Chloroform
Chlorophenol, 2-
Chrysene
Cresol, m-
Cresol, o-
Cresol, p-
ODD
DDE
DDT
Di-n-butyl phthalate
Di-h-octyl phthalate
Dibromo-3-choloropropane, 1,2-
Dichlorobenzene, 1,2-
Dichlorobenzene, 1 ,4-
Dichlorodifluoromethane
Dichloroethane, 1,1- ...„
Dichloroethane, 1 ,2- .,
3ichloroethylene, 1,1-
Dichloroethylene, trans-1,2-
Dichlorophenol, 2,4-
Wastewater
Exit level
(mg/l)
31
16
0.78
17
eqc
eqc
0.074
0.053
0.14
eqc
33
0.00072
0.018
0.0023
0.00081
0.00083
0.007
0.00065
0.00044
0.0085
0.064
16
0.19
240
0.24
0.74
0.012
eqc
0.52
0.42
2
0.054
0.0066
0.0076
0.9
1
0.1
. 8
8
. 0.84
0.00013
eqc
eqc
230
0.002
0.00066
15
0.056
15
0.00016
0.00016
0.00059
3
0.62
UTS
(mg/l)
0.059
0.28
5.6
0.01
0.29
0.24
0.36
0.81
1.9
1.4
1.2
0.059
0.14
0.061
0.11
0.82
0.055
0.033
0.28
0.35
0.63
5.6
0.066
0.017
0.69
3.8
0.057
0.0033
0.057
0.46
0.057
0.1
0.057
0.046
0.044
2.77
0.059
0.77
0.11
0.77
0.023
0.031
0.0039
0.057
0.017
0.11
0.088
0.09
0.23
0.059
0.21
0.025
0.054
0.044
Nonwastewater
Exit level
(mg/kg)
9500
17000
920
1200
260
4
9
eqc
2100
0.1
•110
0.23
4
eqc
0.94
0.12
230
19
170
18000
770
87
14
330
9
0.0098
290
140
2500
28
7
100
10
35
22000
27000
2600
0.0065
0.00094
0.0032
90000
4500
0.66
50000
64
8100
24
6
3
14000
770
UTS
(mg/kg)
3.4
160
*1.8
9.7
30
14
3.4
10
3.4
6.8
7.2
6
28
15
15
2.6
2.5
28
6
0.26
0.28
16
6
15
6
5.7
3.4
5.6
5.6
5.6
0.087
0.087
0.087
28
28
15
6
6
7.2
6
6
6
30
1-4
Exit level
(mg/l)
c
6
0.3
6
0.017
0.053
eqc
16
eqc
0.0054
eqc
0.000066
0.00032
0.0019
0.00036
0.0011
0.0025
0.018
6
0.064
64
0.11
6
0.0016
0.00016
0.16
1
0.0018
0.017
0.32
0.48
0.0012
3
3
0.32
2800
• 0.000062
0.0054
25
0.1
eqc
6
0.011
12
0.00006
0.00006
0.00018
1
0.18
UTS
(mg/l)
2.1
5
7.6
0.014
0.19
4.8
0.86
-------
Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66439
TABLE D-1.—COMPARISON BETWEEN MODELED EXIT LEVELS AND UNIVERSAL TREATMENT STANDARDS—Continued
CAS
94-75-7
78-87-5
10061-01-5
10061-02-6
QA^ AA™9
1**1—1t-A
105-67-9
51-28-5
fiAft_9fL,9
123-91-1 ,.,..
122-3&-4
298-04-4 «.
72-20-8
141-78-6 ..........
RA*XL.7
inA_jii_4
206-44-0
86-73-7
76-44-8-
1024-57-3
87-68-3
319-84-6
319-85-7
53-80-9
67-72-1 .-
193-39-5
78-83-1
7439-92-1
7439-97-6
ft7-Sft-1
72-43-5 .....
74-83-9
74-87-3 ............
78-93-3 »
iftA—iri-1
298-00-0
74-95-3
75-09-2 ....
86-30-6
930-55-2
91-20-3
7440-02-0
98-95-3
606-93-5
108-95-2
298-02-2
1336-36-3
23950-58-5 ......
11A-AR-1
7700.40.0
1746-01-6
95-94-3
127-18-4
eonn*>
7440-284)
8001-35-2
120-82-1
71-55-6
79-01-6
75^9-4
Name
ninlHrin
Dtelhyl phlhalate
Dimethyl phthalate
Dimelhytphenol 2 4-
Dinitrotoluene 24-
Dk>xane,1,4-
Dlphenylamlne
Ethyl ether ••«*•
Le3{J
wercuiy "•••••••• *
Methanol • •
Methoxychtor
Methyl bromide (Bromomethane)
Nlrlffil
Phorate
Safrole
Silvor
Tfinn P ^ 7 s
Trichtoro-1 2 2-trif luoroethane 1 1 ,2-
Trichloroelhane 112-
Trichlofoduoromethane
Wastewater
Exit level
(mg/l)
2
0.023
0.0049
0.0049
0.000059
190
78
4
0.27
0.29
0.17
0.042
15
0.013
0.073
390
27
24
39
28
22
eqc
0.00053
0.0079
eqc
0.00014
0.00044
0.00078
0.0052
0.049
0.0029
39
30
0.3
0.016
78
7
0.37
0.096
78
8
28
0.66
2
0.039
0.2
eqc
14
11
0.084
3
5
0.081
0.002
84
0.11
eqc
21
54
0.16
0.0035
0.93
200
eqc
0.23
0.024
0.0037
2
2
0.05
30
eqc
2200
0.69
74
0.007
0.038
48
UTS .
(mg/l)
0.72
0.85
0.036
0.036
0.017
0.2
0.047
0.036
0.12
0.32
0.55
*NA
0.92
0.017
0.0028
0.34
0.12
0.14
0.057
0.068
0.059
0.0012
0.016
0.055
0.055
0.00014
0.00014
0.0017
0.057
0.055
0.0055
5.6
0.69
0.15
0.24
5.6
0.25
0.11
0.19
0.28
0.14
0.14
0.014
0.11
0.089
0.92
0.013
0.059
3.98
0.068
0.014
0.055
0.055
0.089
0.039
0.021
0.1
0.093
0.067
0.014
0.081
0.82
0.43
0.000063
0.055
0.057
0.057
0.056
0.03
1.4
0.08
0.0095
0.057
0.055
0.054
0.054
0.054
0.02
Nonwastewater
Exit level
(mg/kg)
3100
17
3
3
0.0018
4500
3
11000
56
210
86
13
12000
43
0.26
270000
41000
3400
550000
6000
90000
8
0.026
36
eqc
0.033
0.12
0.1
1500
81
4
55000
570
0.6
140000
19
500
91
110000
17000
40000
1
8400
310
1300
0.053
120000
110
45
0.094
0.13
210
11
3
160000
160
eqc
440
16000
810
11
eqc
eqc
8.000E-06
170
130
29
13000
6200
5
180000
eqc
3500
48000
11
570
26000
UTS
(mg/kg)
10
18
18
18
0.13
28
28
14
160
140
28
170
13
6.2
0.13
33
160
160
10
3.4
3.4
0.066
0.066
5.6
10
0.066
0.066
0.066
2.4
30
3.4
170
0.18
15
30
36
33
160
4.6
15
30
13
35
5.6
14
17
4.6
10
4.8
7.4
6.2
4.6
10
1.5
8.2
16
0.16
0.001
14
6
6
6
7,4
0.078
. 10
2.6
30
19
6
6
6
30
Exit level
(mg/l)
0.6
0.0023
1200
1200
0.54
54
30
1
0.11
0.11
0.064
0.014
3
13
32
110
11
7
8
2
3
0.45
0.0069
eqc
0.11
0.00021
0.69
0.033
eqc
15
12
0.14
30
0.92
30
3
8
23
0.19
0.015
eqc
eqc
3
5
0.032
eqc
12000
eqc
eqc
0.00041
32
eqc
6
2
0.06
eqc
0.36
eqc
0.032
0.0078
0.0077
0.68
0.58
0.019
13
0.11
2400
1
0.054
0.0018
0.013
16
UTS,
(mg/l)
>
0.37
0.025
0.75
5
0.16
0.3
-------
federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
TABLE D-1.—COMPARISON BETWEEN MODELED EXIT LEVELS AND UNIVERSAL TREATMENT STANDARDS—Continued
CAS
95-95-4
88-06-2
93-76-5
93-72-1
96-18-4
126-72-7
7440-62-2
75-01-4
1330-20-7
7440-66-6
Name
Trichlorophenol, 2,4,5-
Trichlorophenol, 2,4,6-
Triohlorophenoxyacetic acid, 2,4,5- (245-T)
Trichlorophenoxypropionic acid, 2,4,5- (Silvex)
Trichloropropane, 1,2,3-
Tris (2,3-dibromopropyl) phosphate
Vanadium
Vinyl chloride
Xylenes (total
Zinc
Wastewater
Exit level
(mg/l)
18
0.054
2
1
1
eqc
10
eqc
22
99
UTS
(mg/l)
0.18
0.035
0.72
0.72
0.85
0.11
4.3
027
0.32
2.61
Nonwastewater
Exit level
(mg/kg)
12000
120
63
6
870
0.36
250
•|
170000
320
UTS
(mg/kg)
7.4
7.4
7.9
7.9
30
0.1
Q
30
Exit level
(mg/l)
4
0.015
0.64
0.48
0.34
eqc
4
150
38
UTS
(mg/l)
0.23
5.3
For the reasons set out in the
preamble, Chapter I of Title 40 of the
Code of Federal Regulations is amended
as follows:
PART 260—HAZARDOUS WASTE
MANAGEMENT SYSTEM: GENERAL
1. The authority citation for part 260
continues to read as follows:
Authority: 42 U.S.C. 6905, 6912(a), 6921-
6927, 6930, 6934, 6935, 6937, 6938, 6939,
and 6974.
2. In § 260.10, add the following
definitions in alphabetical order:
*****
Director means the Regional
Administrator or the State Director, as
the context requires, or an authorized
representative. When there is no
approved State program, and there is an
EPA administered program, Director
means the Regional Administrator.
When there is an approved State
program, Director normally means the
State Director. In some circumstances,
however, EPA retains the authority to
take certain actions even when there is
an approved State program. In such
cases, the term Director means the
Regional Administrator and not the
State Director.
*****
Mono/ill means a landfill where waste
of only one kind or type is placed in or
on land and which is not a pile, a land
treatment facility, a surface
impoundment, an underground
injection well, a salt dome formation, a
salt bed formation, an underground
mine, a cave, or a corrective action
management unit.
PART 261—IDENTIFICATION AND
LISTING OF HAZARDOUS WASTE
3. The authority citation for part 261
continues to read as follows:
Authority: 42 U.S.C. 6905, 6912(a), 6921,
and 6922.
4. Section 261.3 is amended by
revising the first sentence of paragraph
(a)(2)(iv) and the first sentence of
paragraph (c)(2){i) ,to read as follows:
§261.3 Definition of hazardous waste.
*****
-. (a)* * *
', (2)* * *
(iv) It is a mixture of solid waste and
one or more hazardous wastes listed in
subpatt D of this part and has not been
excluded from paragraph (a)(2) of this
section under either §§ 260.20 and
260.22, § 261.36, or § 261.37 of this
chapter; however, the following
mixtures of solid wastes and hazardous
wastes listed in subpart D of this part
are not hazardous wastes (except by
application of paragraph (a)(2) (i) or (ii)
of this section) if the generator can
demonstrate that the mixture consists of
wastewater the discharge of which is
subject to regulation under either
section 402 or section 307(b) of the
clean water act (including wastewater at
facilities which have eliminated the
discharge of wastewater) and:
*****
(c) * * *
(2)* * *
(i) Except as otherwise provided in
paragraph (c)(2)(ii) of this section,
§ 261.36, or § 261.37 of this chapter, any
solid waste generated from the
treatment, storage, or disposal of a
hazardous waste, including any sludge,
spill residue, ash, emission control dust,
or leachate (but not including
precipitation run-off) is a hazardous
waste. * * *
*****
5. A new § 261.36 is added to subpart
D to read as follows:
§ 261.36 Exemption for listed hazardous
wastes containing low concentrations of
hazardous constituents.
(a) Any hazardous waste listed under
this subpart, any mixture of such a
listed waste with a solid waste, or any
waste derived from the treatment,
storage, or disposal of a listed hazardous
waste that does not exhibit any of the
characteristics of hazardous waste in
subpart C of this part 261 and that meets
all of the requirements in § 261.36(b)-
(d) is exempt from all requirements of
parts 262-266 and part 270 of this
chapter. Any such waste which also
meets the requirements of § 261.36(e) is
also exempt from the requirements of
part 268 of this chapter.
(b) Requirements for qualifying for an
exemption.—(I) Testing, (i) For each
waste for which an exemption is
claimed, the claimant must test for all
of the constituents on appendix X to
this part 261 except those that the
claimant determines should not be
present in the waste. The claimant is
required to document the basis of each
determination that a constituent should
not be present. No claimant may
determine that any of the following
categories of constituents should not be
present:
(A) Constituents identified in
appendix VII to this part 261 as the
basis for listing the waste for which
exemption is sought;
(B) Constituents listed in the table to
§ 268.40 of this chapter as regulated
hazardous constituents for LDR
treatment of the waste;
(C) Constituents detected in any
previous analysis of the same waste
conducted by or on behalf of the
claimant;
(D) Constituents introduced into the
process which generates the waste; and
(E) Constituents which the claimant
knows or has reason to believe are
byproducts or side reactions to the
process that generates the waste.
Note: Any claim under this section must be
valid and accurate for all hazardous
constituents; a determination not to test for
a hazardous constituent will not shield a
claimant from liability should that
constituent later be found in the waste. •
(ii) The claimant must develop a
sampling and analysis plan for each
waste for which an exemption is sought.
The plan must identify:
(A) Sampling procedures and
locations sufficient to characterize the
entire waste for which the exemption is
-------
Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
66441
claimed. Grab sampling is acceptable for
this purpose.
(B) Analytical methods that the
claimant will use to determine, for
waslewaters and nonwastewaters, the
total concentration of each constituent
on appendix X to this part except for
those constituents which the claimant
has determined should not be present
under § 261.36(b)(l)(i).
(iii) The claimant must conduct
sampling and analysis in accordance
with the plan.
(iv) The results of the sampling and
analysis must show, for both
wastewaters and nonwastewaters, that
all total constituent concentrations in
the waste are at or below the exemption
levels in appendix X to this part 26l
and, for nonwastewaters, that all
leachable constituent concentrations are
either:
(A) At or below exemption levels in
Appendix X to this part 261, as
determined by testing an extract using
test method 1311 (the Toxicity
Characteristic Leaching Procedure, set
out in "Test Methods for Evaluating
Solid Waste, Physical/Chemical
Methods" (SW-846)), or
(B) Estimated to be at or below
exemption levels using the equation
{[(AxB)+(CxD)]/[B+(20xD)]} leach exit
level, where A=concentration of the
analyte in the liquid portion of the
sample; B=Volume of the liquid portion
of the sample; C=Concentration of the
analyte in the solid portion of the
sample; D=Weight of the solid portion
of the sample.
(2) Treatment requirements. Any
waste that exits using an exit level on
Table B to appendix X to this part 261
must meet the treatment standard for
such a constituent under § 268.40 of this
chapter, regardless of whether or not the
waste is intended for land disposal,
unless the claimant meets the
exemption requirements in § 261.36(e).
(3) Public Notice. The claimant must
submit for publication in a major
newspaper of general circulation, local
to the claimant, a notice entitled
"Notification of Exemption Claim for
Listed Hazardous Wastes Containing
Low Concentrations of Hazardous
Constituents Under the Resource
Conservation and Recovery Act"
containing the following information:
(i) The name, address, and RCRA ID
number of the claimant's facility;
(ii) The applicable EPA Hazardous
Waste Code of the waste for which the
exemption is claimed and the narrative
description associated with the listing
from this part 261 subpart D;
(iii) A brief, general description of the
manufacturing, treatment, or other
process or operation producing the
waste;
(iv) An estimate of the average and
maximum monthly and annual
quantities of the waste claimed to be
exempt;
(v) The name and mailing address of
the agency to which the claimant is
submitting the notification required
under § 261.36(b)(4).
(4) Notification to implementing
agency. Prior to managing any waste as
exempt under this section, the claimant
must send to the Director via certified
mail or other mail service that provides
written confirmation of delivery a
notification of the exemption claim
meeting the following requirements:
(i) The name, address, and RCRA ID
number of the person claiming the
exemption;
(ii) The applicable EPA Hazardous
Waste Codes;
(iii) A brief description of the process
that generated the waste;
(iv) An estimate of the average and
maximum monthly and annual
quantities of each waste claimed to be
exempt;
(v) Documentation for any claim that
a constituent is not present as described
under § 261.36 (b)(l)(i);
(vi) The results of all analyses and
estimates of constituent concentrations
required under § 261.36(b)(l)(iv) and all
quantitation limits achieved;
(vii) Documentation that any waste
that exits using a constituent exit level
from Table B to Appendix X to this part
has met the applicable treatment
standards in § 268.40 of this chapter,
unless the claimant is also claiming the
exemption under § 261.36(e);
(viii) Evidence that the public
notification requirements of
§ 261.36(b)(3) have been satisfied; and
(ix) The following statement signed by
the person claiming the exemption or
his authorized representative:
"Under penalty of criminal and civil
prosecution for making or submitting false
statements, representations, or omissions, I
certify that the requirements of 40 CFR
261.36[b) have been met for all waste
identified in this notification. Copies of the
records and information required at 40 CFR
261.36(d)(7) are available at the claimant's
facility. Based upon my inquiry of the
individuals immediately responsible for
obtaining the information, the information is,
to the best of my knowledge and belief, true,
accurate, and complete. I am aware that there
are significant penalties for submitting false
information, including the possibility of fine
and imprisonment for knowing violations."
(c) Effectiveness of exemption. No
claim shall take effect until the claimant
receives confirmation of'delivery for the
notification required under § 261.36
(d) Conditions for maintaining the
exemption. To maintain any exemption
claimed pursuant to this section, the
claimant must satisfy the following
conditions:
(1) Changes in information. The
claimant must submit to the Director
any change in any information
submitted under § 261.36(b)(4) within
ten business days of the claimant's first
knowledge of the change.
(2) Schedule for retesting. The
claimant must retest the waste for which
the exemption was claimed on the
following schedule:
(i) For the first three years of the
exemption, the claimant must:
(A) Test wastes generated at the time
the exemption is claimed in volumes
greater than 10,000 tons/year on a
quarterly basis;
(B) Test wastes generated at the time
the exemption is claimed in volumes
greater than 1000 tons/year but less than
10,000 tons/year must on a semi-annual
basis;
(C) Test wastes generated at the time
the volume is claimed in volumes less
than 1000 tons/year on an annual basis.
(ii) After the first three years of an
exemption, the claimant must retest the
waste for which the exemption was
claimed on an annual basis.
(3) For every retest the claimant must
prepare and comply with a sampling
and analysis plan meeting the
requirements of § 261.36(b)(l)(ii) and
determine the concentration of:
(i) Each constituent from Table A to
appendix X to this part that was
detected in the initial test within an
order of magnitude below either its total
or leachable exemption level and each
constituent from Table B to appendix X
of this part that is identified as a basis
for listing the waste on appendix VII to
this part or is listed as a regulated
hazardous constituent for the waste in
the table of "Treatment Standards for
Hazardous Wastes" in § 268.40 of this
chapter; and
(ii) Any other constituent that the
claimant has reason to believe may be
newly present in the waste since the
most recent test.
(4) Exemption levels. The
concentrations of all constituents tested
must meet the criteria set out in
§ 261.36(b)(l)(iv).
(5). Treatment requirements. Any
waste exiting by using an exit level for
a hazardous constituent from Table B to
appendix X to this part must meet the
treatment requirements for such a
constituent under § 268.40 of this
chapter prior to exit regardless of
whether or not the waste is intended for
land disposal, unless the claimant meets
-------
66442 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
the exemption requirements in
§261.36(e).
(6) Records. The claimant must
maintain records of the following
information in files on-site for three
years after the date of the relevant test:
(i) For initial testing, all information
submitted under § 261.36(b)(4), all
revisions to such material submitted
under § 261.36(d)(l) and all information
required to be maintained under
§ 261.36(d)(6)(iii);
(ii) For retests:
(A) All volume determinations made
for the purpose of determining testing
frequency under § 261.36(d)(2);
(B) All sampling and analysis plans
required under § 261.36(d)(3);
(C) All analytical results and
estimates of leachable concentrations (if
any) for constituents required to be '
assessed under § 261.35(d)(3);
(D) Documentation showing that a
waste exiting using any constituent exit
level from Table B to appendix X to this
part and is required to be reassessed
under § 261.36(d)(3) has met applicable
treatment standards under § 268.40 of
this chapter, unless the claimant also
claims the exemption under §261.36(e);
and
(iii) For both initial tests and retests,
the claimant must also retain records of:
(A) The dates and times waste
samples :were obtained, and, for total
concentrations and leachable
concentrations that were analyzed, the
dates of the analyses;
(B) The names and qualifications of
the person(s) who obtained the samples;
(C) A description of the temporal and
spatial locations of the samples;
(D) The name and address of the
laboratory facility at which analyses of
the samples were performed;
(E) A description of the analytical
methods used, including any clean-up
and extraction methods;
(F) All quantitation limits achieved
and all other quality control results
(including any method blanks, duplicate
analyses, and matrix spikes), laboratory
quality assurance data, and a
description of any deviations from
published analytical methods or from
the plan which occurred; and
(G) All laboratory documentation that
supports the analytical results, unless a
contract be'tween the claimant and the
laboratory .provides for the
documentation to be maintained by the
labotatofy for the period specified in'
§ 26i.'3;6, (b)(2) and also provides for the
availability of the documentation to the
claimant upon request.
Note: Failure to satisfy any of these.
conditions voids the exemption and requires
management of the waste for which the ,
exemption has been claimed as hazardous
waste. Submission of notification to the
Director that all waste conditions have been
satisfied re-establishes the exemption for all
waste generated after that date.
(e) Exemption from part 268
requirements.—If all hazardous
constituent levels in a waste qualifying
for exemption are at or below the
appendix X to this part concentration .
levels at the waste's point of generation,
prior to any mixing with other solid or
hazardous wastes and prior to any
treatment, the waste is exempt from all
requirements of part 268 of this chapter.
The claimant also must meet the
following documentation requirements:
(1) For initial tests, in place of the
certification required at § 261.36
(b)(4)(ix), the claimant must submit the
following statement signed by the
person claiming the exemption or his
'authorized representative and, if the
claimant is not the generator of the
waste, also signed by the generator or
his authorized representative:
Under penalty of criminal and civil
prosecution for making or submitting false
statements, representations, or omissions, I
certify that, for the waste identified in this
notification, the concentration of all
constituents assessed as required under
§ 261.36 (b)(l)(iv) met the applicable levels in
appendix X to this part 261 at the point of
generation and that all other requirements of •
40 CFR § 261.36 (b) have been met. Copies of
the records and information required at 40
CFR § 261.36 (d)(4) are available at the
claimant's facility. Based upon my inquiry of
the individuals immediately responsible for
obtaining the information, the information is,
to the best of my knowledge and belief, true,
accurate, and complete. I am aware that there
are significant penalties for submitting false
information, including the possibility of fine
and imprisonment for knowing violations.";
or
(2) For every retest required under
§ 261.36(d)(2), the claimant must
document that the concentrations of all
constituents retested as required under
§ 261.36(d)(3) met the applicable levels
in appendix X to this part 261 at the
waste's point of.generation, must
include information supporting this
claim from the waste's generator if the
generator is not the person asserting the
claim, and must retain such
documentation in files on-site for three
years after the date of the relevant test.
(f) Nothing in this paragraph
preempts, overrides, or otherwise
negates the provision in § 262.11 of this
chapter, which requires any person who
generates a solid waste to determine if
that waste is a hazardous waste.
(g) In an enforcement action, the
burden of proof to establish
conformance with the exemption
criteria shall be on the claimant.
6. A new § 261.37 is added to read as
follows:
§ 261.37 Exemption for listed hazardous
wastes containing low concentrations of
hazardous constituents and managed in
landfills and monofills.
(a) Any hazardous waste listed under
this subpart, any mixture of such a
listed waste with a solid waste, or any
waste derived from the treatment,
storage or disposal of such a listed waste
is exempt from regulation as a
hazardous waste under parts 262-266
and 270 of this chapter if it meets the
requirements in § 261.37(b) and (d)
(including the requirement that all
hazardous constituents present in the
waste be at or below the levels listed in
appendix XI to this part and that the
waste be disposed in a landfill or
monofill, but not a land application
unit). To maintain the exemption, the
waste must satisfy the conditions in
§ 261.37(e). Any such waste which also
meets the requirements of 261.37(f) is
also exempt from the requirements of ,
part 268 of this chapter.
(b) Requirements for qualifying for an
exemption—(1) Testing, (i) For each
waste for which an exemption is
claimed, the claimant must test for all
of the constituents on appendix XI to
this part 261 except those that the
claimant determines should not be
present in the waste. The claimant is
required to document the basis of each
determination that a constituent should
not be present. No claimant may
determine that any of the following
categories of constituents should not be
present:
(A) Constituents identified in
appendix VII to this part 261 as the
basis for listing the waste for which
exemption is sought;
(B) Constituents listed in the table to
§ 268.40 as regulated hazardous
constituents for LDR treatment of the
waste;
(C) Constituents detected in any
previous analysis of the same waste
conducted by or on behalf of the
claimant;
(D) Constituents introduced into the
process which generates the wasteland
(E) Constituents which the claimant
knows or has reason to believe are
byproducts or side reactions to the ;
process that generates the waste.
Nqte: Any claim under this section must be
valid and accurate for all hazardous
constituents; a determination not to test for
a hazardous constituent will not shield a
claimant from liability should that •
constituent later be found in the waste. .
(ii) The claimant must develop a
sampling and analysis plan for each
-------
Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66443
waste for which an exemption is sought.
The plan must identify:
(A) Sampling procedures and
locations sufficient to characterize the
entire xvaste for which the exemption is
claimed. Grab sampling is acceptable for
this purpose.
(B) Analytical methods that the
claimant will use to determine, for
wastewaters and nonwastewaters, the
total concentration of each constituent
on appendix XI to this part except for
those constituents which the claimant
has determined should not be present
under § 261.37(b)(l)(i).
(iii) The claimant must conduct
sampling and analysis in accordance
with the plan.
(iv) The results of the sampling and
analysis must show, for both
wastewaters and nonwastewaters, that
all total constituent concentrations in
the waste are at or below the exemption
levels in appendix XI to this part 261
and, for nonwastewaters, that all
leachable constituent concentrations are
either:
(A) At or below exemption levels in
appendix XI to this Part 261, as
determined by testing an extract using
test method 1311 (the Toxicity
Characteristic Leaching Procedure, set
out in "Test Methods for Evaluating
Solid Waste, Physical/Chemical
Methods" (SW-846)), or
(B) Estimated to be at or below
exemption levels using the equation
{(AxB)-f (CxD)}/{B+(20xD)} < leach exit
level, where A=concentration of the
analyte in the liquid portion of the
sample; B = Volume of the liquid
portion of the sample; C=Concentration
of the analyte in the solid portion of the
sample; D = Weight of the solid portion
of the sample.
(2) Treatment requirements. Any
waste that exits using an exit level on
Table B to appendix XI to this Part 261
must meet the treatment standard for
such a constituent under § 268.40 of this
chapter, regardless of whether or not the
waste is intended for land disposal,
unless the claimant meets the
exemption requirements in § 261.37(fJ.
(3) Public Notice. The claimant must
submit for publication in a major
newspaper of general circulation, local
to the claimant, a notice entitled
"Notification of Exemption Claim for
Listed Hazardous Wastes Containing
Low Concentrations of Hazardous
Constituents and Managed in Landfills
and Monofills Under the Resource
Conservation and Recovery Act"
containing the following information:
(i) The name, address, and RCRA ID
number of the claimant's facility;
(ii) The applicable EPA Hazardous
Waste Code of the waste for which the
exemption is claimed and the narrative
description associated with the listing
from this part 261 subpart D;
(iii) A brief, general description of the
manufacturing, treatment, or other
process or operation producing the
waste;
(iv) An estimate of the average and
maximum monthly and annual
quantities of the waste claimed to be
exempt;
(v) The name and mailing address of
the agency to which the claimant is
submitting the notification required
under § 261.37(b)(4);
(vi) The following statement:
The exemption for this waste from the
hazardous waste regulatory scheme is
conditioned disposing of the waste in a
landfill or monofill (and not a land
application unit.)
(4) Notification to implementing
agency. Prior to managing any waste as
exempt under this section, the claimant
must send to the Director via certified
mail or other mail service that provides
written confirmation of delivery a
notification of the exemption claim
meeting the following requirements:
(i) The name, address, and RCRA ID
number of the person claiming the
exemption;
(ii) The applicable EPA Hazardous
Waste Codes;
(iii) A brief description of the process
that generated the waste;
(iv) An estimate of the average and
maximum monthly and annual
quantities of each waste claimed to be
exempt;
(v) Documentation for any claim that
a constituent is not present as described
under § 261.37(b)(l)(i);
(vi) The results of all analyses and
estimates of constituent concentrations
required under § 261,37(b)(l)(iv) and all
quantitation limits achieved;
(vii) Documentation that any waste
that exits using a constituent exit level-
from Table B to appendix XI to this part
have met the applicable treatment
standards in § 268.40, of this chapter,
unless the claimant is also claiming the
exemption under § 261.37(f);
(viii) Evidence that the public
notification requirements of
§ 261.37(b)(3) have been satisfied; and
(ix) The following statement signed by
the person claiming the exemption or
his authorized representative:
Under penalty of criminal and civil
prosecution for making or submitting false
statements, representations, or omissions, I
certify that the requirements of § 261.37(b)
have been met, including the requirement
that all hazardous constituents, present in the
waste are at or below the levels listed on
appendix XI to'this part, for all listed wastes
identified in this notification. I also certify
that arrangements have been made to dispose
of the waste in a landfill or monofill (and not
a land application unit). Copies of the
records and information required at § 261.37
(e)(7) are available) at the claimant's facility.
Based upon my inquiry of the individuals
immediately responsible for obtaining the
information, the information is, to the best of
my knowledge and belief, true, accurate, and
complete. I am aware that there are
significant penalties for submitting false
information, including the possibility of fine
and imprisonment for knowing violations.
(5) The claimant must receive
confirmation of delivery for the
notification required under § 261.37
(c) Tracking, storage, treatment and
other management prior to disposal.
Until a listed hazardous waste meeting
the requirements of § 261.37(b) is placed
in a landfill or monofill, it remains
subject to all requirements of parts 262-
266 and 270 of this chapter. The waste
is also subject to the requirements of
part 268 of this chapter unless it
qualifies for an exemption under
§261.37(f).
(d) Disposal in a landfill or monofill.
The claimant must ensure that any
listed waste meeting the requirements of
§ 261.37(b) for which an exemption is
sought is disposed of in either a landfill
or monofill (and not a land application
unit). The landfill or monofill need not
be subject to regulation as a hazardous
waste management unit. The waste
becomes exempt as soon as it is placed
in a landfill or monofill unit.
(e) Conditions for maintaining the
exemption. To maintain any exemption
claimed pursuant to this section, the
claimant must satisfy the following
conditions:
(1) Compliance with modified
hazardous waste manifest system. If the
landfill or monofill in which the waste
is disposed is not a hazardous waste
disposal unit subject to part § 264.71-
264.72 or §265. 71-265.72 of this
chapter, the claimant must:
(i) Ensure that the manifest form is
returned from the disposal facility, and
(ii) Obtain information showing that
the disposal facility designated on the
manifest received the waste for which
the exemption is sought and placed it in
either a landfill or monofill (and not a
land treatment unit) .
(2) Changes in information. The
claimant must submit to the Director
any change in any information
submitted under §261. 37(b)(4) within
ten business days of the claimant's first
knowledge of the change.
(3) Schedule for retesting. The
claimant must retest the waste for which
the exemption was claimed on the
following schedule:
-------
66444 Federal Register / Vol. 60, No: 245 / Thursday, December 21, 1995 / Proposed Rules
(i) For the first three years of the
exemption, the claimant must:
(A) Test wastes generated at the time
the exemption is claimed in volumes
greater than 10,000 tons/year on a
quarterly basis;
(B) Test wastes generated at the time
the exemption is claimed in volumes
greater than 1000 tons/year but less than
10,000 tons/year must on a semi-annual
basis;
(C) Test wastes generated at the time
the volume is claimed in volumes less
than 1000 tons/year on an annual basis.
(ii) After the first three years of an
exemption, the claimant must retest the
waste for which the exemption was
claimed on an annual basis.
(4) For every retest the claimant must
prepare and comply with a sampling
and analysis plan meeting the
requirements of § 261.37(b)(l)(ii) and
determine the concentration of:
(i) Each constituent from Table A to
appendix XI to this part that was
detected in the initial test within an
order of magnitude below either its total
or leachable exemption level and each
constituent from Table B to appendix XI
to this part that is identified as a basis
for listing the waste on appendix VII to
this part or is listed as a regulated
hazardous constituent for the waste in
the table of "Treatment Standards for
Hazardous Wastes" in § 268.40 of this
chapter; and ' •••••'•
(ii) Any other constituent that the
claimant has reason to believe may be
newly present in the waste since the
most recent test.
(5) Exemption levels.—The
concentrations of all constituents tested
must meet the criteria set out in
§261.37(b)(l)(iv).
(6) Treatment requirements.—Any
waste exiting by using an exit level for
a hazardous constituent from Table B to
Appendix XI to this part must meet the
treatment requirements for such a
constituent under § 268.40 of this
chapter prior to exit regardless of
whether or not the waste is intended for
land disposal, unless the claimant meets
the exemption requirements in
§261.37(f).
(7) Records.—The claimant must
maintain records of the following
information in files on-site for three
years after the date of the relevant test:
(i) For initial testing, all information
submitted under § 261.37(b)(4) and all
revisions to such material submitted
under §261.37(e)(2), all information -
obtained under § 261.37(e)(l), and all ,,
information required to be maintained
under § 261.37(e)(7)(iii);
(ii) For retests:
(A) All volume determinations made
for the purpose of determining testing
frequency under § 261.37(e)(3);
(B) All sampling and analysis plans
required under § 261.37(e)(4);
(C) All analytical results and
estimates of leachable concentrations (if
any) for constituents required to be
assessed under § 261.37 (e)(5);
(D) Documentation showing, that a
waste exiting using any constituent exit
level from Table B to Appendix XI to
this part has met applicable treatment
standards under § 268.40 of this chapter,
unless the claimant also claims the
exemption under § 261.37(f); and
(iii) For both initial tests and retests,
the claimant must also retain records of:
(A) The dates and times waste
samples were obtained, and, for total
concentrations and leachable
concentrations that were analyzed, the
dates of the analyses;
(B) The names and qualifications of
the person(s) who obtained the samples;
(C) A description of the temporal and
spatial locations of the samples;
(D) The name and address of the
laboratory facility at which analyses of
the samples were performed';
(E) A description of the analytical
methods used, including any clean-up
and extraction methods;
(F) All quantitation limits achieved
and all other quality control results
(including any method blanks, duplicate
analyses, and matrix spikes), laboratory
quality assurance data, and a
description of any deviations from
published analytical methods or from
the plan which occurred; and
(G) All laboratory documentation that
supports the analytical results, unless a
contract between the claimant and the
laboratory provides for the,
documentation to be maintained by the
laboratory for the period specified in
§ 261.37 (b)(2) and also provides for the
availability of the documentation to the
claimant upon request. Failure to satisfy
any of these conditions voids the
exemption and requires management of
the waste for which the exemption has
been claimed as hazardous waste.
Submission of notification to the
Director that all waste conditions have
been satisfied re-establishes the
exemption for all waste generated after
that date.
(f) Exemption from part 268
requirements.—If all hazardous
constituent levels in a waste qualifying
for exemption are at or below the '
appendix XI to this part concentration
levels at the waste's point of generation,
prior to any mixing with other solid or
hazardous wastes and prior to any
treatment, the waste is exempt from all
requirements of part 268 of this chapter.
The claimant also must meet the
following documentation requirements:,
(1) For initial tests, in place of the
certification required at § 261.37
(b)(4)(ix), the claimant must submit the
following statement signed by the
person claiming the exemption or his
authorized representative and, if the
claimant is not the generator of the
waste, also signed by the generator or
his authorized representative:
Under penalty of criminal and civil
prosecution for making or submitting false
statements, representations, or omissions, I
certify that, for the waste identified in this
notification, the concentration of all
constituents assessed as required under
§ 261.37 (b)(l)(iv) met the applicable levels in
appendix XI to this part 261 at the point of
generation and that all other requirements of
40 CFR 261.37 (b) have been met. I also
certify that arrangements have been made to
dispose of the waste in a landfill or monofill
(and not a land application unit). Copies of
the records and information required at 40
CFR 261.37 (e)(7) are available at the
claimant's facility. Based upon my inquiry of
the individuals immediately responsible for
obtaining the information, the information is,
to the best of my knowledge and belief, true,
accurate, and complete. I am aware that there
are significant penalties for submitting false
information, including the possibility of fine
and imprisonment for knowing violations.";
and
(2) For every retest required under
§ 261.37(e)(3), the claimant must
document that the concentrations of all
constituents retested as required under
§ 261.37(e)(4) met the applicable levels
in appendix XI to this part 261 at the'
waste's point of generation, must
include information supporting this
claim from the waste's generator if the
generator is not the person asserting the
claim, and must retain such
documentation in files On-site for three
years after the date of the relevant test.
(g) Nothing in this paragraph
preempts,, overrides, or otherwise
negates the provision in § 262.11 of this
chapter, which requires any person who
generates a solid waste to determine if
that waste is a hazardous waste.
(h) In an enforcement action, the
burden of proof to establish
conformance with the exemption
criteria shall be oh the claimant.
7.. Appendix X is added to read as ,
follows: . . .
-------
Appendix X
TABLE A.—MODELED OR EXTRAPOLATED RISK-BASED Exnr LEVELS
CAS No.
83-32-9
*>nfl— Qfi-fl
57-64-1
75-05-8
98-86-2
75-36-5
5g-)_08-2
53-95-3
107-02-8
70 06 1
1 07—1 3—1
1402-68-2
116-06-3
309-00-2
107-18-6
107-05-1
92-67 1
2763-96-4
504 24 5
61—82 5
62-53-3
120—12 7
7440—36-0
1 40-57-8
7440-38-2
2465-27 2
115-02-6
7440-39-3
71—43 2
92-87 5
106-51—4
98-07 7
50-32—8
205—99—2
205—82 3
207—08 9
191 24 2
100—51—6
100-44 7
56-55-3
225-51-4
7440—41 7
39638—32—9
111— 44— 4
1 1 7—81 7
542 88-1
598—31 2
75-27—4
75-25—2
101 55—3
357 57 3
71-36-3'
88-85-7
85-68 7
7440-43-9
86-74-8
Nam0
Acelonilrile
Acetytaminofluorene, 2-
Acrolein
Aldicarb
Aldrin
Allyl Alcohol '.
Allyl chloride
Benzotrichloride
Benzyl chloride
Benz(a) anthracene
Bis(chlorometfiyl) ether ...
Bromodichloromethane
Butanol — ..\:....
Butyl-4 6-dinitrophenol 2-sec- (Dinoseb) : ;.........*. •....
Cadmium
Carbazole -
MCL benchmark option
Wastewater
Totals
(mgn
31
(')
16
0.78
17
t1)
(')
0.028
(')
(')
(')
(')
(')
(')
(')
0.074
0.028
0)
(')
V)
0.053
(1)
0.14
15
0.38
0)
(1)
28
0.021
(1)
15
(1)
0.0023
0.00081
0.0029
0.0029
0.0029
39
1
0.00072
0.0029
0.00083
0.007
0.00065
0.00044
(1)
0.024
0.0085
0.064
0.024
(1)
16
0.034
240
0.038
(')
Nonwasiewater
Totals
(mg/kg)
9500
4
17000
920
1200
(')
(')
3
3
(')
0.96
(')
(1)
(')
0)
260
3
(1)
0)
(1)
4
4
9
6900
(1)
(')
(')
2100
110
(')
6900
140
0.23
4
4
4
4
2700
38
0.1
4
(1)
0.94
0.12
230
(')
31
19
170
31
(1)
1800
770
87
14
(1)
Leach
(mg/l)
5
(')
6
0.3
6
0)
6
0)
0)
(')
(1)
0.54
(')
0)
(1)
t1)
(')
0)
0.017
(')
0.053
11
0.15
0)
t1)
11
0.009
0)
11
(')
0.0036
0.000066
0.0012
0.0012
0.0012
15
15
(1)
0.0012
0.00032
0.0019
0.00036
0.11
(1)
0.012
0.0025
0.018
- 0.012
(1)
6
0.011
64
0.015
(')
Toxfcity benchmark option
Wastewaler
Totals
(mg/l)
31
(')
16
0.78
17
(1)
(')
0.028
(')
(')
(1)
0)
(')-
(')
(1)
0.074
0.028
(')
(1)
(')
0.053
(1)
0.14
15
(')
(')
(1)
33
0.018
0)
15
(1)
0.0023
0.00081
0.0029
0.0029
0.0029
39
1
0.00072
0.0029
0.00083
0.007
0.00065
0.00044
(1)
0.023
0.0085
0.064
0.023
(1)
16
0.19
240
0.24
(1)
Nonwastewater
Totals
(mg/kg)
9500
4
17000
920
1200
(1)
(1)
3
3
(')
0.96
(1)
(')
(1)
(1)
260
3
(')
(')
0)
4
4
9
6900
(1)
(1)
(1)
2100
110
(1)
6900
140
0.23
4
4
4
4
2700
38
0.1
4
t1)
0.94
0.12
230
(1)
31
19
170
31
(1) -
18000
770
87
14
(1)
Leach
(rng/l)
5
(')
6
0.3
6
(')
6
0)
(1)
(1)
(1)
0.48
0)
(1)
(')
(1)
0)
0)
0.0,17 ,
(')
0.053
11
(')
(1)
(1)
16
0.0054
(')
11
O
(1)
O'.ooooee
(1)
(1)
0)
15
15
0)
(1)
0.00032
0.0019
0.00036
0:0011
(1)
0.015
•0.0025
0.018
0.015
(')
6
0.064
64
0.11
0)
I*
I
o
O5
O
to
tfc.
01
r
CD
O
CD
CO
IS3
CO,
CD
CJ1
;O
CO
-CD
a-
O5
CJ1
-------
Appendix X—Continued
TABLE A.—MODELED OR EXTRAPOLATED RISK-BASED EXIT LEVELS
CAS No.
75-15-0
353-50-4
56-23-5
75-87-6
305-03-3
57-74-9
494-03-1
126-99-8
107-20-0
106-47-8
108-90-7
510-15-6
124-48-1
75-00-3
110-75-8
67-66-3
59-50-7
107-30-2
91-58-7
95-57-9
7005-72-3
5344-82-1
542-76-7
7440-47-3 .'.
218-01-9
6358-53-8
7440-48-4
7440-50-8
108-39-4
95-48-7
106-44-5
4170-30-3
57-12-5
14901-08-7
108-94-1
131-89-5
50-18-0
20830-81-3
72-54-8
53-19-0
72-55-9
3424-82-6
50-29-3
789-02-6
2303-16-4
132-64-9
192-64-9
189-64-0
189-55-9
194-59-2
226-36-8
53-70-3
224-42-0
96-12-8
764-41-0
110-57-6
Name
Carbon disulfide ... .
Carbon oxyfluoride ...
Carbon tetrachloride
Chloral . .
Chlorambucil ..
Chlordane
Chlornaphazin
Chloro-1 ,3-butadiene, 2-(Chloroprene)
Chloroac6tald6hyde
Chloroaniline p- . .. .
Chlorobenzene .......
Chlorobenzilate . .
Chlorodibromomethane . . ...
Chloroethane (ethyl chloride)
Chloroethyl vinyl ether 2- . ...
Chloroform ...
Chloro-m-cresol, p-
Chloromethyl methyl ether ...
Chloronaphthalene, 2-
Chlorophenol, 2- . .
Chlorophenyl phenyl ether, 4-
Chlorophenyl thiourea 1-0-
Chloropropionitrile 3- . ...
Chromium ...
Chrysene ......
Citrus red No. 2 . ...
Cobalt . . .
Coooer
Cresol, m- ....
Cresol, o-
Cresol p- . . '
Crotonaldehyde ...
Cyanide
Cycasin
Cyclohexanone
Cyclohexyl-4,6-dinitrophenol, 2-
Cyclophosphamide '. . ...
Daunomycin
ODD ....
ODD (o.p'l .
DDE . .
DDE (o.p1)
DDT
DDT (o,p') ...
Diallate
Dibenzofuran . .
Dibenzo[a e]pyrene
Dibenzo[a hjpyrene
Dibenzo[a,i]pyrene . . . .
Dibenzo[c,g]carbazole, 7H-
Dibenz(a,h)acridine
Dibenz(a,h)anthracene ... . .
Dibenz[a,j]aoridine -
Dibromo-3-chloropropane, 1 ,2-
Dichloro-2-butene 1 4-
Dichloro-2-butene, trans-1 .4-
• MCL benchmark option
Wastewater
Totals
(mg/l)
0.74
(1)
0.012
(1)
n
(')
(1)
0.52
(1)
0.42
0.68
0.054
0.0066
0.024
(')
0.0076
0.27
(1)
0.27
0.9
0.024
n
0.27
0.62
0.1
(1)
0.62
670
8
8
0.84
8
(1)
(1)
(1)
0)
(1)
(1)
0.00013
(1)
0)
(')
0)
(1)
-0.26
8
0.0029
0.0029
0.0029
(')
0.0029
(1)
0.0029
0.0022
• 0.024
0.024
Nonwastewater
Totals
(mg/kg)
330
O
9
(1)
O
0.0098
(1)
290
(1)
140
2500
7
28
31
140
7
140
31
140
100
31
(1)
140
10
35
n
9
6
22000
27000
2600
1200
20
(')
(')
(')
O
O
0.0065
(1)
0.00094
(')
0.0032
t1)
. :1
27000
4
' 4
4
4
4
(1)
4
0.66
31
31
Leach
(mg/l)
6
(')
0.012
0)
(1)
0.036
(')
O
0.16
0.19
0.0057
0.0018
0.012
(1)
0.017
0.033
(')
0.033
0.32
0.012
(1)
(1)
0.24
0.0012
(1)
(1)
1100
3
3
0.32
6
(1)
(')
'(')
(')
(')
(1)
2800
(')
0.000062
(1)
0.0054
(1)
0.46
2
0.0012
0.0012
0.0012
(1)
0.0012
(1)
0.0012
0.00038
0.012
0.012
Toxicity benchmark option
Wastewater
Totals
(mg/l)
0.74
(1)
0.012
(')
(1)
(')
(1)
0.52
(')
0.42
2
0.054
0.0066
0.023
(1)
0.0076
0.081
(1)
0.081
0.9
0.023
(1)
(1)
1
0.1
(')
1
670
8
8
0.84
8
(')
(1)
(1)
(1)
(1)
(1)
0.00013
(1)
(1)
(')
(1)
D
0.26
8
0.0029
0.0029
0.0029
(1)
' 0.0029
(1)
0.0029
0.00066
0.023
0.023
Nonwastewater
Totals
(mg/kg)
330
n
9
(')
(1)
0.0098
. (1)
290
(1)
140
2500
7
28
31
140
7
140
31
140
100
31
(1)
140
10
35
(1)
9
6
22000
27000
2600
1200
20
0)
(1)
(1)
O
O
0.0065
(1)
0.00094
(1)
0.0032
(1)
1
27000
• 4
4
4
4
4
(1)
4
0.66
31
31
Leach
(mg/l)
6
(1)
0.0016
(1)
0)
0.00016
(1)
.n
0.16
1
0.0057
0.0018
0.015
(1)
0.017
0.032
(1)
0.032
0.32
0.015
(')
(')
0.48
0.0012
(')
(1)
1100
3
3
0.32
6
(1)
(1)
(1)
(1)
0)
(1)
2800
(1)
0.00062
(1)
0.0054
(1)
0.46
3
(1)
(1)
t1)
t1)
t1)
(')
(1)
0)
0.016
0.015
§
n
B-
E-
ff
O)
p
I
d
CB
O
CD
B
cr
CD
CD
CO
Ol
o
en
CD
P-
-------
96-23-1 ™.
95-50-1 -.
541-73-1
106-46-7 ..............
91-94-1
75-71-8 ..„..„„„...
75-34-3
107-06-2
75-35-4
156-59-2
156-60-5
111-91-1
98-87-3
120-83-2
87-65-0
94-75-7
78-87-5
542-75-6
10061-01-5
10061-02-6
60-57-1
1464-53-5
84-66-2
311-45-5
56-53-1 ."..
94-58-6....
60-51-5
131-11-3
77-78-1
60-11-7.
119-93-7
57-97-6
79-44-7
122-09-8
105-67-9
119-90-4 ...
84-74-2
99-65-0
100-25-4
534-52-1
51-28-5
121-14-2 ...
606-20-2 .'
117-64-0
123-91-1
122-39-4
122-66-7 ...
298-04-4
541-53-7 :..
115-29-7
959-98-8
33213-65-9 ....
1031-07-8
145-73-3
72-20-8
7421-93^*
53494-70-5....
106-89-8
51-43-4
110-80-5
141-78-6
51-79-6
107-12-0
60-29-7
97-63-2
DfcWofo-2-propanol, 1.3-.
Kchtowbenzene, 1.2- ™»
DJchtorobenzeno, 1,3- .....
Wcbtofobenzeoe, 1,4-,™
Dlchtorobenzidino, 3.31 -
DtchtorodOuoromethane..
Dtehtoroeihane, 1,1-
Dlchloroethane, 1,2- ........
DIchtoroeihylBne, 1,1- .....
DlchtoroethylBne, ds-1,2- .„
Dichtoroethylene, irans-1,2-
Dichloromelhoxy ethane.
Dichtoromethylbenzene (benzal chloride) „..
Dichlorophenol, 2,4-
Dichlorophenol, 2,6-
Dichlorophenoxyacetic acid, 2,4- (2,4-D)
Dichloropropane, 1,2-
Dichloropropene, 1,3-
Dichloropropene, cls-1,3-
Dichloropropene, lrans-1,3-
Dieldrin
Diepoxybutane, 1,2,3,4-(2,2'-bioxirane)
Diethyl phthalate
Diethyl-p-nitrophenyl phosphate
Diethylstilbestrol
Dihydrosafrole
Dimethoate
Dimethyl phthalate
Dimethyl sulfate
Dimethylaminoazobenzene, p-
Dimethylbenzidine, 3,3'
Dimethylbenz(a)anthracene, 7,12
Dimethylcarbamoyl chloride
Dimethylphenethylamine, alpha, alpha-
Dimethyiphenol, 2,4-
Dimethyoxybenzidine, 3,3-
Di-n-butyl phthalate
Dinitrobenzene, 1,3-
Dinitrobenzene, 1,4- ,....
Dinitro-o-cresol, 4,6-
Dinitrophenol, 2,4-
Dinitrotoluene, 2,4-
Dinitrotoluene, 2,6-
Di-n-octyl phthalate
Dioxane, 1,4-
Diphenylamine
Diphenylhydrazine, 1,2- -.
Disulfoton
Dithiobiuret
D, salts, esters, 2,4-
Endosulfan .'
Endosulfan I
Endosulfan II ........
Endosulfan sulfate
Endothall
Endrin ,
Endrin aldehyde .,
Endrin ketone
Epichlorohydrin
Epinephrine
Ethoxyethanol, 2-
Ethyl acetate _
Ethyl carbamate .....
Ethyl cyanide (propionitrile) ........
Ethyl ether
Ethl methacrylate
0.27
8
0.024
1
0.0037
15
0.00016
0.007
0.0035
039
0.42
0.024
0.024
0.62
0.024
0.27
0.12
0.0028
0.0049
0.0049
0.000059
15
190
(])
15
29
78
(i)
0.028
d)
(1)
(1)
0.16
4
0.034
880
0.017
(')
(')
0.27
029
0.17
0.002
0.042
15
0.16
0.013
(1)
0.0069
6
0.0069
0.0069
0.0069
(')
0.073
0.0069
0.0069
0.34
(i)
15
390
15
0.16
27
24
140
50000
31
64
C1)
8100
24
6
3
5400
14000
31
31
770
31
3100
17
32
3
3
0.0018
6900
4500
(<)
6900
2
3
(')
3
(1)
0)
0)
20
11000
(')
90000
6
(1)
0)
56
210
86
4500
13
1200
20
43.
0)
o
73
0.19
0.19
0.19
0)
0.26
0.19
0.19
44
(1)
6900
270000
6900
20
41000
3400
0.033
2
0.012
022
0)
12
0.0006
0.009
0.013
0.11
0.16
0.012
0.012
0.18
0.012
0.11
0.012
0)
1200
1200
0.54
11
54
i'i
11
0.77
30
0)
(1)
0)
(1)
(1)
0.11
1
0.01
100
• 0.0064
0)
(')
0.11
0.11
0.064
0.1
0.014
3
0.11
13
(1)
0.54
0.94
0.54
0.54
0.54
0.54
24
0.54
0.54
5400
0)
15
110
11
0.11
11
7
0.081
15
0,023
0.056
0.0037
15
0.00016
0.00016
0.00059
2
3
0.023
0.023
0.62
0.023
2
0.023
0.0028
0.0049
0.0049
0.000059
15
190
15
29
78
(1)
0.028
<]) ,
[!j
0.16
4
0.034
230
0.017
(])
027
0,29
0.17
0.002
0.042
15
0.16
0.013
n
0.0069
6
0.0069
0.0069
. 0.0069
(1)
0.073
0.0069
0.0069
0.34
15
390
15
0.16
27
24
140
50000
31
64
(')
8100
24
6
3
5400
14000
31
31
770
31
3100
17
32
3
3
0.0018
6900
4500
6900
2
3
(')
3
(])
0)
20
11000
(')
90000
. 6
(1)
0)
56
210
86
4500
13
12000
20
43
(1)
(1)
73
0.19
0.19
0.19
(')
0.26
0.19
0.19
44
6900
270000
6900
20
41000
3400
0.032
6
0.015
0.011
(')
12
O.OOOC
O.OOW
0.0001
0.64
1
0.015
0.015
0.18
0.015
0.6
0.002:
(')
1200
1200
0.54
11
54
11
0.77
30
(')
0)
•(?.
(')
0.11
1
0.01
25
0.006
(')
0)
0.11
0.11
0.064
0.1
0.014
3
0.11
13
0)
0.48
0.94
0.48
0.48
0.48
0.48
32
0.48
0.48
5400
15 •
110
11
0.11
11
7
3?
Or
CD
el
-------
Appendix X—Continued
TABLE A.—MODELED OR EXTRAPOLATED RISK-BASED EXIT LEVELS
CAS No.
62-50-0
100-41-4'.
106-93-4 .
75-21-8
96-45-7
151-56-4
52-85-7 .
640-19-7 .
62-74-8
206-44-0 .
86-73-7
16984-48-8
50-00-0
64-18-6
765-34-4
319-86-8 . .
76-44-8
1024-57-3 .
87-68-3
118-74-1
319-84-6
319-85-7
58-89-9 . . .
77-47-4
67-72-1-
70-30-4 .
1888-71-7
757-58-4
591_75_6
302-01 2 •
193-39-5
74-88-4
78-83-1
465-73-6
78-59-1
120-58-1 . .
143-50-0
303-43-4
7439-92-1
108-31-6
123-33-1
109-77-3
148-82-3 . . . .
7439-97-6 . .
126-98-7
74-93-1
67-56-1
91-80-5
16752-77-^5 .
72-43-5 .-.
74483-9 . '
74-87-3 .- . • .
78-93-3 ....
1338-23-4
60-34-4 ...
108-10-1
r ;. " i,' • • • ' '." • ~
1 "-.• Name
Ethyl methanesulfonate
Ethylbenzene
Ethylene Dibromide
Ethylene thiourea • ... .
Ethyleneimine (aziridine) . . ......
Famohur . . . . .
Fluoracetamide 2- ; ;
•Fluoracetic acid, sodium salt
Fluoranthene
Fluorene . ... . .'
Formaldehyde . . .
Formia Acid • .
Glycidyialdehyde • •
HCH delta- ... ....
Heptachlor epoxide . . . ...
Hexachloro-1 ,3-butadiene ~
Hexachlorobenzene
Hexachloro- cyclohexane, alpha- (alpha-BHC)
Hexach- lorocyclo- hexane beta- (beta-BHC)
Hexach- lorocyc- lohexane gamma- (Lindane)
Hexachloroethane . . . .
Hexae- thylte- traphosphate . . . .
Hexanone 2- . . • . .
lndeno(1 ,2,3-cd) pyrene -.
lodomethane .: .....; *
Isobutyl alcohol -. -.
Isodrin
Isosafrole . . . .....
Kepone-
Lasiocarpine
Lead ,
Maleic anhydride
Maleic hydrazide
Malononitrile .-.
Melphalan ... . •
Mercurv .... .... . . ... . -. ..
Methacrylonitrile
Methanethiol
Methanol
Methapyrilene
Methomyl -. . . . . ... • . . .
Methoxychlor . . .- . .... ... .....•.•.-..
Methyl bromide (Bromomethane) -. . . . . :~
Methyl chloride (Chloromethane) . . ... . •:....;...
Methyl ethyl ketone
Methyl ethyl ketone peroxide . . . ....
Methyl hydrazine . ... ,.'.....
Methvl isobutvl ketone
MCL benchmark option
Wastewater
Totals
(mg/l) .
0.0055
8
0.00093
15
(1)
O
(1) -
(1)
(1) :-
28
22
(1) '
270
(1)
0.0069
(1)
0.00053
0.0079
n
0.00014
0.00044
0.00078
0.0052
: 0,049
(1)
0.27
'• (1)
8
: O •
0.0029
0.024
39
(1)
0.53
15
(1)
(1)
30
(1)
0.16
0.16
(1)
0.06
0.016
(1)
78
0.16
o
i 7
: 0.37
1 0.096
78
(')
n.'
8
Nonwastewater
Totals
(mg/kg)
(1)
550000
0.0075
6900
(1)
(1)
(1)
(1)
(1)
6000
• 90000
49
300000
(1)
0.19
8
0.026
36
n
0.0033
0.12
0.1
1500
81
(1)
140
(1)
1200
20
4
31
55000
n
740
6900
(1)
(')
570
6900
20
20
(1)
0.6
9
0)
140000
20
(1)
19
500
91
110000
(')
(1)
17000
Leach
(mg/l)
12000
2
0.00075
11
0)
D .
0.54 B
0)
(1)
2
3
11
110
(1)
0.54
66
0.0069
0.018
0.11
0.00021
2
0.033
0)
0.033
(1)
6
0)
(1)
0.012
15
0.54
0.16
11
(1)
(1>
12
t1)
0.11
0.11
' (1)
0.023
(1)
(')
30
0.11
0.54
0.92
30
(1)
(1)
3
Toxicity benchmark option
Wastewater
Totals .
(mg/l)
0.0055
39
0.00036
15
(1)
: (1)
(1)
(1)
0)
28
22
(1)
270
(1)
0.0069
(1)
0.00053
0.0079
(1)
0.00014
0.00044
0.00078
0.0052
0.049
(1)
0.081
(1)
8
(1)
0.0029
0.023
39
0
0.53
15
(1)
(1)
30
0)
0.16
0.16
(1)
0.3
0.016
(1)
78
0.16
(1)
7
0.37
0.096
78
(1)
(1)
8
Nonwastewater
Totals
(mg/kg)
(1)
550000
0.0075
6900
(')
(1)
(1)
0)
(1)
6000
90000
49
300000
(1)
0.19
8
0.026
36
(1)
0.033
0.12
0.1
1500
81
(1)
140
(1)
1200
20
4
31
55000
(1)
740
6900
0)
(1)
570
6900
20
20
(1)
0.6
9
(1)
140000
20
(1)
19
500
91
110000
(')
0)
17000
Leach
(mg/l)
12000 .. .
8. ;
(1)
11
(1)
0)
0.48
0)
n
2
3
11
110 '
(1)
0.48
0.45
0.0069
(1)
0.11
0.00021
0.69
0.033
(1)'
0.032
(')
6
(1)'
(1)
0.015
15
0.48
0.16
11
(')
(1)
12
(1)
0.11
0.11
(1)
0.14
(1)
(1)
30
0.11
0.48 "
0.92
30 '
0) :. ' •
(1) .
3
O)
8-
S1
PU'
1
05
O
f
5
I.
cr
CO
OI
o
13
O
-co" .
CD
cx
CO
-------
80-62-6 —
66-27-3—
91-57-6 —
298-00-0 _.
75-55-8—
58-49-5
74-95-3
75-09-2
101-14-4 „..
70-25-7
56-04-2
50-07-7
7439-98-7..
91-20-3
130-15-4....
86-88-4
134-32-7....
7440-02-0
54-11-5
88-74-4
99-09-2
100-01-6
98-95-3-
55-86-7
51-75-2
126-85-2
302-70-5
55-63-0
99-55-8
88-75-5
100-02-7
79-46-9
56-57-5
55-18-5
62-75-9
924-16-3
10595-95-6
1116-54-7
621-64-7
86-30-6
4549-40-0
59-89-2
759-73-9
684-93-5
615-53-2
16543-55-8
100-75-4
930-55-2
13256-22-9
103-85-5
1615-80-1
152-16-9
20816-12-0
297-97-2
126-68-1
123-63-7
56-38-2
608-93-5
76-01-7
82-68-8
87-86-5
62-44-2
85-01-8
108-95-2
62-38-4
Meihyl memaoytalo
Methyl melhanesutfonata
Methyl naphthalene, 2-
Meihyl parathton
MethytazMcfoe. 2-
Methylchotanthrene, 3-«™™««....™.
Methylene bromide....—
Methylene chtorkfa
Methylenebis. 4,4'-(2-chtoroaniline)
Methyl-niitro-rotfosoguanldloB (MNNG)
MelhyltWouracIl
Milomycin C
Molybdenum _ „
Naphthalene
Naphthoquinone. 1,4-
Naphthyl-2-thlourea, 1-
Naphthylamine, 1-
Naphthylamine, 2-
Nickel
Nicotine and salts
Nitroaniline, 2-
Nitroaniline, 3-
Nitroaniline, 4-
Nitrobenzene
Nitrogen mustard
Nitrogen mustard Hydrochloride salt
Nitrogen mustard N-Oxide
Nitrogen mustard N-Oxide, HCI salt
Nitroglycerine
Nitro-o-toluidine, 5-
Nitrophenol, 2-
Nitrophenol, 4-
Nitropropane, 2-
Nitroquinoline-1-oxide, 4-
Nitrosodiethylamine
Nitrosodimethylamine
Nitrosodi-n-butylamine
Nitre- somethyle thylamine
N-Nitrc- sodietha- nolamine
N-Nitrosodi-n-propylamine
N-Nitro- sodiphe- nylamine
N-Nitrosomethyl vinyl amine
N-Nitrosomorpholine
N-Nitroso-N-ethylurea
N-Nitroso-N-methylurea
N-Nitroso-N-methylurethane
N-Nitrosonornicotine
N-Nitrosopiperidine
N-Nitroopyrrolidine
N-Nitrososarcosine .-.
N-Phenylthiourea
N,N-Diethylhydrazine
Octame- thylpyro- phospho- ramide ".
Osmium Tetroxice
O.O-Diethyl O-pyrazinyl phosphorothioate ....
O,O,O-Triethyl phosphorothioate
Paraldehyde
Parathion
Pentachlorobenzene
Pentachloroethane
Penta- chloro- nitre-benzene (PCNB)
Pentachlorophenol
Phenacetin
Phenanthrene
Phenol
Phenyl mercuric acetate
28
0.12
C)
0.66
0)
C)
0.029
0.039
0)
C)
C)
C)
2
14
15
(')
0.16
0.16
4
0.16
C)
(1)
0.028
0.084
(')
0)
C)
C)
0)
0.028
0.025
(')
0)
0.16
C)
0)
0)
(')
0)
(')
0.2
(1)
0.16
C)
0.16
0)
(1)
0)
0.27
(1)
0.12
0.12
8
3
5
0.024
0.27
0.002
15
0)
84
40000
2
A
1
C)
C)
8400
310
C)
C)
0)
C)
110
120000
6900
C)
20
20
110
20
3
3
3
45
O
0)
C)
0)
0)
3
3
0)
0.13
20
0)
(')
0.023
1300
0)
20
(')
20
0
0.053
31
(1)
2
C)
1200
0.13
210
31
11
3
6900
4
160000
' 0)
8
6
C)
23
(')
C)
0.0085
0.09
C)
C)
2
3
11
C)
0.11
0.11
2
0.11
0)
0)
0)
• 0.032
0)
0)
0.11
C)
(')
0)
0)
0)
C)
C)
C)
0.11
C)
0.11
C)
C)
C)
«
C)
C)
C)
0.11
(1)
6
6
6
12000
0.054
0.012
C)
0.00041
11
C)
32
C)
28
0.12
C)
0.66
(')
C)
2
0.039
C)
(')
0)
0)
2
14
15
C)
0.16
0.16
11
0.16
(')
0)
0.028
0.084
(')
C)
0)
(')
(')
0.028
0.0.25
C)
C)
0.16
t1)
0)
m
m
(1)
m
0.2
0.16
(i)
0.16
(1)
(')
0)
0)
(')
0)
C)
0.27
0)
0.12
0.12
8
3
5
0.023
0.081
0.002
15
(1)
84
0)
40000
2
4
1
C)
0)
8400
310
C)
0)
C)
C)
110
120000
6900
C)
20
20
110
20
3
3
3
45
0)
0)
(})
3
3
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0.13
20
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C)
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0.023
1300
20
(1)
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C)
C)
0.053
C)
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(1)
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C)
1200
0.13
210
31
11
3
6900
4
160000
C)
8
6
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0.19
0.015
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11
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0.11
0.11
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0.032
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Appendix X—Continued
TABLE A.—MODELED OR EXTRAPOLATED RISK-BASED EXIT LEVELS
• : ' . . 1
CAS No.
25265-76-3
108-45-2
106-50-3
298—02 2
298-06-6
3288-58-2
2953-29-9
85-44-9
109-06-8
1336-36-3 .
23950-58-5
1120-71-4 ...
1 07-1 0-8
51-52-5 ...
107-19-7
129-00-0
110-86-1 ....
50-55-5
108-46-3
81-07-2 . .
94-59-7
7782-49-2 . . .
7440-22-4
18883-66-4 ...
57-24-9
100-42-5
18496-25-8
.1746-01-6
95-94-3
630-20-6 . . .
79-34-5
127-18-4 . .
58-90-2
107-49-3 . . . :
3689-24-5
7440-28-0 . . .'.
62-55-5
39196-18-4
108-98-5
79-19-6 ,
62-56-6
137-26-8
7440-31-5 '
108-88-3 . . .
584-84-9
95-80-7 ,
823-40-5 .
496-72-0
636-21-5 . ..
95-53-4
106-49-0.
8001-35-2
76-13-1
Name
'Phenylenediamines (N.O.S.) .........
Phenylenediamine p-
Phosphorodithioic acid o-o-diethyl ester ...
Phthalic anhydridG ... . . ...
Picoline 2-
Polychlorinated biphenyls
Pronamide . . .
Propane sultone 1,3-
Propylthiouracil
Propyn-1-ol 2- . . ...
Pyrene . . ... . .
Pyridine
Reserpine
Resorcinol . ... .
Saccharin and salts
Safrole ....
Selenium . '. . . . .
Silver . "
Streptozotocin . . . . . .
Strych'nine
Stryene ... . ...
Sulfide
TCDD,2,3,7,8-
Tetrachlorobenzene, 1 ,2,4,5-
Tetrachloroethane 1,112-.
Tetrachloroethane, 1 ,1 ,2,2-
Tetrachloroethylene . .
Tetrachlorophenol, 2,3,4,6-
Tetraethylpyrophosphate
Tetraethyldithiopyrophosphate '
Thallium (I)
Thioacetamide . . ... ... ...
Thiofanox ;
Thiophenol . . . ....
Thiosemicarbazide
Thiourea . . . . . ".
Thiram
Tin ...
Toluene ..... .
Toluene diisocyanate
Toluenediamine 24-. . . ....
Toluenediamine 26- . .
Toluenediamine,3,4-
Toluidine hydrochloride, o- . . . ...
Toluidine o-
Toluidine p- . . . ... ...
Toxaphene
Trichloro-1 .2.2-trifluoroethane.1 .1 .2-
MCL benchmark option
Wastewater
Totals
(mg/l)
0.16
0.78
0.16
0.11
(')
(')
(')
(')
(')
0.16
(')
21
(')
0.16
0.12
39
54
0.16
0.16
.(')
(')
0.0035
0.23
200
(')
0.045
0.91
0)
0.23
0.024
0.0037
0.026
2
(')
0.23
0.035
(1)
0.12
0.12
(')
(')
(')
(') '
6
(')
(1)
- 0.16
0.16
0.16
(')
0)
(')
0.77
Nonwastewater
Totals
(mg/kg)
20
780
20
160
(') •
(')
(')
(')
2400
20
(')
440
(')
20
(')
37000
16000
810
20
(1)
(')
11
(')
(1)
(')
(')
630000
8.000E-06
170
130
29
13000
6200
6900
3
5
(')
(')
2
(')
D
(')
0)
180000
- 20
n
20
20
20
2
0.13
(')
Leach
(mg/l)
0.11
0.3
0.11
(')
0)
(')
0)
(')
0.11
0.009
6
(')
0.11
6
15
2
0.06
0:11
0.54
(1)
(')
0.089
(')
0.016
0.22
5.400E-07
0.032
0.0078
0.0077
0.0085
0.58
(1)
0.014
(1)
6
6
(1)(1)
(1)
0.54
(')
2
(')
(')
0.11
0.11
0.11
D
(1)
6
0.17
Toxicity benchmark option
Wastewater
Totals
(mg/l)
0.16
0.78
0.16
0.11
0)
(1)
(1)
(')
(')
0.16
(')
21
(1)
0.16
0.12
39
54
0.16
0.16
D
D
0.0035
0.93 .
200
D
0.045
64
(1)
0.23
0.024
0.0037
2
2
D
0.23
0.05
O
0.12
0.12
f1)
(1)
(')
(')
30
0)
(')
0.16
0.16
0.16
(1)
0)
(1)
2200
Nonwastewater
Totals
(mg/kg)
20
780
20
160
(1)
(')
(')
(')
2400
20
(')
440
(')
20
(1)
37000
16000
810
20
f1)
(1)
11
(1)
0)
(1)
(')
630000
8.000E-06
170
130
29
13000
6200
6900
3
5
D
(')
2
(1)
(')
D
D
180000
20
(1)
20
20
20
2
0.13
(1)
Leach
(mg/l)
0.11
0.3
0.11
(')
(') '
(')
(')
(')
:0.11
(')
6
(')
0.11
6
15
2
0.06
0.11
0.48
(1)
(')
0.36
D
0.016
15
(')
0.032
0.0078
0.0077
0.68
0.58
(')
0.019
(')
6
6
(')
(1)
0.48
(1)
13
(')
(1)
0.11
0.11
0.11
(')
(')
0.11
2400
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Federal Register / Vol. 60, No. ,245 / Thursday, December 21,' 1995 / Proposed Rules 66451
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-------
TABLE B.—QUANTITATION-BASED EXIT LEVELS—Continued
CAS No.
75_87_6
305-03-3 .
57_74_9 .
494-03-1
107-20-0 .
110-75-8 . .
107-30-2 . ..
5344-82-1 .
542-76-7
6358-53-8
7440-48-4
57-12-5
14901-08-7
108-94-1
131-89-5
50-18-0 .. . .
20830-81-3 ......
53-19-0
72-55-9
3424-82-6
50-29-3
789-02-6 ....
192-65-4
189-64-0
189-55-9 .;
194-59-2
226-36-8
53-70-3
224-42-0
96-12-8
91-94-1
542-75-6
311-45-5 ....'.
56-53-1 ..;
77-78-1
60-11-7
119-93-7
57-97-6
79-44-7
119-90-4
100-25-4
534-52-1
541-53-7
145-73-3
51-43^t
62-50-0
106-93-4
96-45-7
151-56-4
52-85-7
640-19-7
62-74-8
.16984-48-8
50-00-0
765-34^4 "
76-44-8
Name
Chloral .... . . . . . ...
Chlorambucil . . ....
Chlordane
Chlornaphazin
Chloroacetaldehyde . .
Chloroethyl vinyl ether 2- .
Chloromethyl methyl ether
Chlorophenyl thiourea 1-o-
Chloroproplonitrile, 3- .-.
Citrus red No. 2
Cobalt
Cyanide
Cycasin ... . .
Cyclohexanone ......
Cyclohexyl-4,6-dinitrophenol, 2-
Cyclophosphamide
Daunomycin ......
ODD (o D1)
DDE . ... . .
DDE (o p1) .. . . . .
DDT ...
DDT (o D1)
Dibenzo[a e]- pyrene
Dibenzo[a,h]- pyrene
Dib8nzo(a,i)pyrene '.....
Dibenzo(c,g)car- bazole, 7H-
Dibenz(a,h)acri- dine
Dibenz(a,h)ant- hracene • •
Dibenz(a,j)aoridine ... . . . .
Dibromo-3-chloropropane 1 2-
Dichlorobenzidine, 3,31- : -.... •.
Dichloropropene, 1 ,3-
Diethyl-p-nitrophenyl phosphate ..- ;
Diethylstilbestrol
Dimethyl sulfate . .
Dimethylaminoazobenzene, p- . ...
Dimethylbenzidine, 3,31- . . . .
Dimethylbenz- (a)anthraoene, 7,12-
Dimethylcarbamoyl chloride .-. ..
Dimethyoxybenzidine, 3,31- . ...
Dinitrobenzene 1 ,4- ....
Dinitro-o-cresol 46-..
Dithiobiuret ...
D, salts, esters, 2,4- . .
Endothall .......
Epinephrine .
Ethyl methanesulfonate . . . .
Ethylene Dibromide . . . -
Ethylene thiourea ... .
Ethyleneimine (aziridine)
Famphur . . ...
Fluoracetamide, 2- . . . . •
Fluoracetic acid, sodium salt . ......
Fluoride .•.
Formaldehyde . . ...
Glycidylaldehyde . . , ' .
Heptachlor :. :.
MCL benchmark option
Wastewater
. Totals
(mg/l)
D
(')
0.00004
(1)
(1
(1)
(1)
(1)
(1)
0.2
n
10
0.1 '
(1)
(1)
(1)
• .0.000058
'(')
0.000081
(1)
' 0.01
0.00003
' O
0.0078
(1)
0.0033
0.00037
(1)
0.04
0.05
(1)
0.1
(1)
(')
(1)
0.02
. (1)
(1)
0.023
(1)
0.00004
Nonwastewater
Totals
(mg/kg)
(1)
(')
(1)
(1)
(1)
(')
n
7
(1)
(')
(1)
(1)
(1)
0.084
0.12
(')
1
(1)
0.7
0.039
(1)
3
3
(1)
0^
(1)
(1)
0.018
(1)
(1)
,• 1
(1)
0)
(1)
Leach
(mg/l)
(1)
(')
(1)
(1)
n
(1)
(1)
0.1
(1) '
0.5
0.2
• (1)
10
0.1
(1)
(1)
(1)
(')
(1)
0.0.1
0.00003
0.0024
0.0009
(1)
0.0078
D
0.01
: 0.0033
0.00037
(1)
0.04
0.05
I1)
(1).
(') "
n
n
(1)
(1)
Toxicity benchmark option
Wastewater
Totals
(mg/0
(1
('
0.00004
(1
(1
(1
D
(1)
0.1
(1)
0.2
(1)
10
0.1
t1)
(1)
(')
0.000058
(1)
0.000081
(')
0.01
0.00003
(1)
0.0078
(1)
0.0033
0.00037
(1)
0.04
0.05
(1)
0.1
(1)
(1)
(1)
0.02
(')
0)
0.023
0)
0.00004
Nonwastewater
Totals
(mg/kg)
(')
(i)
(1)
(1)
(1)
(1)
(1)
7
(1)
(1)
(1)
(1)
(')
0.084 .
0.012
0)
1
(1)
0.7
0.039
(1)
7
3
3
(1)
0.2
(1)
(1)
0.018
(')
(1)
1
(1)
(1)
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Leach
(mg/l)
1)
')
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1)
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0.1
(1)
0.5
0.2
(1)
10
0.1
(1)
(1)
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(1)
0.001
0.0002
0.0002
0.01
0:0002 . .
0.00003
0.001
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0.0024
0.0009
• (1)
0.0078
(1)
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0.00037
(')
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0.05
(1)
(1)
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(1).
(1)
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-------
Federal Register / Vol. 60, No, 245 / Thursday, December 21, 1995 / Proposed Rules 66453
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TABLE B.—QUANTITATION-BASED EXIT LEVELS—Continued
CAS No.
Qvl CQ_7
18883-66-4
57 24—9
i7Afi-ni R
107-49-3
62 55-5
oqiqc iD_d
79-19 6
62-56-6
137 26—8
7440-31-5
584 84 9
95_8Q_7
95 53-4
106-49 0
8001—35 2
75_70_7
126 72 7
52-24-4
72-57-1
66-75-1
75-01—4
81-81-2
Name
TCDD 2378-
Tetraethyl pyrophosphate . . '
Thiourea ... • •
Tin
Toluensdiarnine 2,4-
Trichloromethanethiol
Tris(l-azridinyl) phosphine sulfide
Warfarin , ....
MCL benchmark option
Wastewater
Totals
(mg/l)
(1)
1.000E-08
-(')
1 .
(')
0) -
0.05
8
n
0.013
0.012
0.017
0.0013
0)
0.025
0)
(1)
(')
0.05
Nonwastewater
Totals
(mg/kg)
5
0.3
(')
3
(')
• (1)
3
(')
(')
3
500
1
0.03
(')
0)
(1)
(')
3
Leach
(mg/l)
0.0021
0.0021
0)
(1)
1
«
(1)
8
0)
0.013
0.012
0.017
n
0.025
(')
(')
(1)
Toxicity benchrpark option
Wastewater
Totals
(mg/l)
n
1 .OOOE-08
(')
1
(1)
f1)
0.05
8
(1)
0.013
0.012
0.017
0.0013
n
0.025
n
n
n
0.00017
0.05
Nonwastewater
Totals
(mg/kg)
5
0.3
(1)
3
D
«
3
(')
n
3
500
1
0.03
n
0
o
o
3
Leach
(mg/l)
0.0021
0.0021
(1)
1. OOOE-08
(1)
1
(')
(')
8
0.013
0.012
0.017
n
0.025
(1)
(1)
(1)
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01
H
'c
.a
CD
;
-------
8. Appendix XI is added to road as follows:
TABLE A.-
Appendix XI
-MODELED OR EXTRAPOLATED RISK-BASED CONDITIONAL EXIT LEVELS
CAS No.
83-32-9
208-96-8
67-64-1
75-05-8
98-86-2
75-36-5
591-08-2
53-96-3
107-02-8
79-06-1
107-13-1
1402-68-2
116-06-3
309-00-2
107-18-6
107-05-1
92-67-1
2763-96-4
504-24-5
61-82-5
62-53-3
120-12-7
7440-36-0
140-57-8
7440-38-2
2465-27-2 „
115-02-6..
7440-39-3
71-43-2
92-87-5
106-51-4
98-07-7
50-32-8
205-99-2
205^-82-3
207-08-9
191-24-2
100-51-6
100-44-7
56-55-3
225-51-4
7440-41-7
39638-32-9
111-44-4
117-81-7
542-88-1
598-31-2
75-27-4
75-25-2
101-55-3 :....
357-57-3
71-36-3
88-85-7 .
85-68-7
Name
Acenaphthene
Acenaphthylene
Acetone
Acetonitrile
AcetoDhenone . . .
Acetyl chloride
AcetyI-2-thiourea, 1-
Acetylaminoffuorne, 2-
Acrolein
Acrylamide
Acrylonitri'le
Aflatoxins
Aldicarb
Aldrin
Allyl alcohol
Allyl chloride
Aminobiphenyl, 4-
Aminomethyl-3-isoxazolol, 5-
Aminopyridine, 4-
Amitroie
Aniline
Anthracene
Antimony
Aramite
Arsenic
Auramine .
Azaserine
Barium
Benzene ,.* -
Benzidine .. .
Benzoquinone, p- .
Benzotrichloride
Benzo(a)pyrene
Benzo(b) fluoranthene
Benzo(j) fluoranthene
Benzo(k) fluoranthene ,
Benzo[Q, h, ijperylene ....
Benzyl alcohol
Benzyl chloride
Benz(a) anthracene
Benz[c] acridine
Beryllium
Bis (2-chloroisopropyl) ether
Bis(2-chlore- thyljether
Bis(2-ethy- lexyljphthalate
Bisfchlor- o'methyl)ether
Bromoacetone
Bromodich- loromethane
Bromoform (Tribromomethane)
Bromophenyl phenyl ether 4- '
Brucine
Butanol
Butyl-4 6-dinitrophenol 2-sec- (Dinoseb)
Butylbenzvl- Dhthalate .-..:. .......
MCL benchmark option
Wastewater
Totals
(mg/l)
31
0)
16
0.78
17
0)
0)
0.028
(')
0)
0)
(')
(')
0)
o)
0.074
0.028
(')
0)
(')
0.053
(1)
0.14
15
0.38
(1)
(1)
28
0.021
(1)
15
«
0.0023
0.00081
0.0029
0.0029
0:0029
39
1
0.00072
0.0029
0.00083
0.007
0.00065
0.00044
(1)
0.024
0.0085
0.064
- 0.024
(1)
16
0.034
240
Nonwastewater
Totals
(mg/kg)
63000
4
39000
2200
75000
(')
590
88
11
0) '
2
(')
6
0.0045
0)
260
88
(1)
(')
(')
170
4
85.
6900
0.53
0)
0)
34000
250
0)
6900
1200
0.23
4
4
4
4
130000
81
0.1
4
0.22
97
1
740
(1)
140
240
1600
140
(1)
41000
6000
87
Leach
(mg/1)
13
(')
21
1
22
(')
24
0.038
(')
(')
(')
4
0)
(')
0.038
0)
(')
o
0.072
(')
0.18
37
0.52
O
(1)
38
0.039
(1)
37
(1)
0.0036
0.000066
0.0012
0.0012
0.0012
53
50
n
0.0012
0.0011
0.0088
0.002
0.11
(1)
0.054
0.011
0.081
0.054
(1)
21
0.043
67
Toxfcfty beochmaik option
Wastewater
Totals
(mg/l)
31
(')
16
0.78
17
(')
0)
0.028
0)
(')
0)
(')
(')
(1)
(')
0.074
0.028
(1)
t1)
(')
0.053
(1)
0.14
• 15
(1)
(1)
(1)
33
0.018
(1)
15
(')
0,0023
0.00081
0.0029
0.0029
0.0029
39
1
0.00072
0.0029
0.00083
0.007
0100065
0.00044
V)
0.023
0.0085
0.064
0.023
(1)
16
0.19
240
Nonwastewater
Totals
(mg/kg)
63000
4
39000
2200
75000
0)
590
88
11
(')
2
(')
6
0.0045
(')
260
88
(')
(1)
0
170
4
85
6900
0.53
(1)
(')
34000
250
(1)
6900
1200
0.23
4
4
4
4
130000
81
0.1
4
0.22
97
1
740
t1)
140
240
1600
140
(1)
41000
6000
87
Leach
(mg/l)
13
(')
21
1
22
(1)
24
0.038
(1)
0)
(1)
3
(1)
(1)
0.038
(')
o .
o -
0.072
(')
0.18
37
0.00052
(')
(1)
45
0.023
(1)
37
(1)
(1)
0.000066
(1)
(1)
(1)
53
50
(1)
(1)
0.001 1
0.0088
0.002
0.0011
(')
0.053
0.011
0.081
0.053
(1)
21
0.24
67
CL
I
I.
(A
ff
05
K)
^
OI
CO
O.
a
CD
n
I
CO
CO
01
CD
P-
I
CD
CO
Oi
yi
01
-------
TABLE A.—MODELED OR EXTRAPOLATED RISK-BASED CONDITIONAL EXIT LEVELS—Continued
CAS No.
7440-43 9
86-74-8
75-15-0
353 50-4
56-23 5
75-87-6
305-03-3
57 74 g
494-03-1
107-20-0
106-47-8
108-90-7
510-15-6
124—48-1
75-00-3
110-75-8
67-66-3
59-50-7
1 07-30-2
91-58-7
95-57-8
7005-72-3
5344-82-1
542 76-7
7440-47-3 . .
218-01-9
6358-53-8
7440-48-4
7440-50-8
1 08-39-4
95-48-7 .
106-44 5
4170-30-3
57_12-5
14901-08-7
1 08-94-1
131 89 5
50-1 8-0
20830-81-3
72-54-8
53_ig_0
72-55-9
3424-82-6 ....
50_29-3
789-02-6
2303-1 6-4
132-64-9
1 92-65-4
189 64-0
189-55-9
194 59-2
226-36-8
53-70-3
244-42-0
96-12-8
764^1-0
Name
Chloral
Chlorambucil •
Chlofdane ....
Chlornaphazin
Chloroacetaldehyde
Chlororoaniline p-
Chlorobenzene
Chlorobenzilate •
Chlorodibromomethane .
Chloroethane (ethyl chloride) .... .'.
Chloroethyl vinyl ether 2- ...
Chloro-m-cresol p-
Chloromethyl methyl ether
Chloronaphthalene 2-
Chlorophenol 2-
Chlorophenyl phenyl ether, 4-
Chiorophenyl thiourea 1-o-
Chloropropionitrile 3-
Chromium
Chrysene
Citrus red No 2
Cobalt
Cresol, o-
Cyanide
Cycasin ....
Cyclohexanone . .
Cyclophosphamide . ....
Daunomycin . ...
ODD :
ODD (0 p') ...
DDE . . .
DDE (o,p')
DDT
DDT (OP')
DiaHate . ...
Dibenzofuran
Dibenzo- [a e]pyrene .
Dibenzo- [a ijpyrene
Dibenzo- [c gjcarbazole 7H-
Dibenz- (a h)anth- racene
Dibenz- [a jjacridine . .
Dichloro-2-butene, 1,4-
MCL benchmark option
Wastewater
Totals
(mg/l)
0.038
(')
0.74
0
0.012
O
n
o
o
0.52
(1)
0.42
0.68
0.054
0.0066
0.024
(1)
0.0076
0.27
0)
0.27
0.9
0.024
0)
0.27
0.62
0.1
o
' 0.62
670
8
8
0.84
8
n
(')
o
«
«
D
0.00013
(1)
n
0)
(')•
(1)
0.26
8
0.0029
0.0029
0.0029
(1)
0.0029
(1)
0.0029
0.0022
0.024
Nonwastewater
Totals
(mg/kg)
110
«
3800,
(1)
130
(1)
0
0.19
(1)
1700
(1)
. 5800
41000
14
200
140
O
76
1200
140
1200
8500
140
(1)
1200
16
35
(1)
110
950
30000
46000
2900
38000
51
n
38000
42
(1)
n
0.26
(1)
0.033
(1) -
0.11
(1)
7
38000
4
4
4
4
4
D
4
7
140
Leach
(mg/l)
0.051
0)
24
n
0.055
(1)
(1)
0.036
0)
(1)
0.56
0.81
0.029
0.0079
0.054
0)
0.075
0.068
(1)
0.068
1
0.054
(1>
(1)
0.31
. 0.0012
(1)
(1)
3800
11
11
1
22
0.37
(1) •
22
(')
(')
(1)
6800
(1)
0.000062
(')
• 0.0054
(1)
11
9
0.0012
0.0012
0.0012
n
0.0012
(1)
0.0012
0.0017
0.054
Toxicity benchmark option
Wastewater
Totals
(mg/l)
0.24
0)
0.74
0)
0.012
P)
(<)
(1) •
n-
0.52
(1)
0.42
2
0.054
0.0066
0.023
(')
0.0076
0.081
(1)
0.081
0.9
0.023
(')
0)
1
0.1
(1)
1
670
8
8
0.84
8
(1)
(1)
(1)
n
n
<1)
0.00013
(1)
«
' (1)
(1)
(')
0.26
8
0.0029
0.0029
0.0029
(')
0.0029
(1)
0.0029
0.00066
0.023
Nonwastewater
Totals
(mg/kg)
110
t1)
3800
0)
130
(')
(1)
0.19
(')
1700
C)
5800
41000
14
200
140
(1)
76
1200
140
•1200
8500
140
(1)
1200
16
35
t1)
110
950
30000
46000
2900
38000
51
(1)
38000
42
t1)
t1)
0.26
D
0.033
(1)
0.11
(1)
7
38000
4
4
4
4
4
n
4
7
140
Leach
(mg/l)
0.32
(1)
24
(1)
0.0077
0)
C)
0.00016
(1)
(1)
0.56
6
0.029
0.0079
0.053
D
0.075
0.06
(1)
0.06
1
0.053
n •
D
2
0.0012
(1)
1
3800
11
11
1
22
0.37
(1)
22
(1)
(')
(')
6800
(1)
0.000062
(1)
0.0054
n
11
11
(1)
(1)
f1)
(1)
(1)
f1)
(1)
0.00052
0.053
O3
U1
05
s.
'S
EL
O
O5
O
a
CO
n
I
CD
i-l
IS)
CD
CO
01
"d
S
v
o
ca
CD
D-
I
ciT
CO
-------
110-57-6.. ;
96-23-1 ™,
95-50-1 ™ ...
541-73-1
105-46-7
91-94-1 .„„„„.„.„
75-71-8
75-34-3
107-06-2
75-35-4
156-59-2 „„
150-60-5
111-91-1 .„
98-87-3
120-83-2
87-65-0
94-75-7
78-67-5
542-75-6
10061-01-5 „...
10061-02-6
60-57-1
1464-53-5
84-66-2
311-45-5
56-53-1
94-58-6
60-51-5
131-11-3
77-78-1
60-11-7
119-93-7
57-97-6
79-44-7
122-09-8
105-67-9
119-90-4
84-74-2
99-65-0
100-25-4
534-52-1
51-28-5
121-14-2
606-20-2
117-84-0
123-91-1
122-39-4
122-66-7
298-04-4
541-53-7
115-29-7
959-98-8
33213-65-9
1031-07-8 ...,.
145-73-3
72-20-8
7421-93-4
53494-70-5
106-89-8
51-43-4
110-80-5
141-78-6
51-79-6
107-12-0
60-29-7
Dtchkxo-2-butono, Uans-1,4- ..,,.«.,,«.«™,m™.,.,.,.m..«..,,«.._™..™...,
DJcWoro-2-fXOpa/iol, 1,3- .,m««,,«.,«._M™_.™™_™™..™m™- ™.™
Dichkxobenzene, 1,2- ......™..»MTO-,^™.,™™«.™...™^m«™m.^.m..
Dichkxobenzene. 1,3- •.„.„ „ „ .™ .„„„.„
Dichtorobenzene, 1,4- „ ..™.™«
Dichtorobenzkfme, 3,3- ™™..™™™.™».m......™.».Mm..........m.._..m.
Dichtofo- dtlluofomelhana ™...™.™.™.......M.
Dichtoroelhaoe, 1 ,1- ....... „. .. .....
Dichtoroethaoe, 1,2-
Dichtoroethy lene, 1,1-
Dichtorelhylene, cis-1 ,2- .....
Dichtorelhylene, trans-1,2- „
Dichtoromethoxy ethane
DIchloromethylbenzene (benzal chloride) „..
Dichlorophenol, 2,4-
Dichlorophenol, 2,6-
Dichlorophenoxyacetio acid 2 4- (2 4-D)
Dichloropropane, 1 ,2-
Dlchloropropene, 1 ,3-
Dlchloropropene, cis-1 ,3-
Dichloropropene, trans-1,3- „.
Dieldrin
Diepoxybutane, 1 ,2,3,4- (2,2'-bioxirane) ...... .
Diethyl phthalate
Dfethyl-p-nitrophenyl phosphate
Diethylstilbestrol
Dihydrosafrole
Dimethoate
Dimethyl phthalate
Dimethyl sulfate
Dimethyl- aminoazo- benzene, p-
Dimethylbenzidine, 3,3'-
Dimethyl- benz(a)- anthracene, 7,12-
Dimethylcarbamoyl chloride
Dimethyl- phenethyl- amine, alpha, alpha-
Dimethylphenol, 2,4-
Dimethyoxy- benzidine, 3,3'-
Di-n-butyl phthalate
Dinitrobenzene 1 3-
Dinitrobenzene 1 4-
Dinitro-o-cresol, 4,6-
Dinitrophenol 2 4-
Dinitrotoluene, 2,4-
Dinitrotoluene, 2,6- . ..
Di-n-octyl phthalate
Dioxane, 1,4-
Diphenylamine
Diphenylhydrazine, 1 2-
Disulfoton
Dithiobiuret
D, salts, esters, 2,4- . .
Endosulfan
Endosulfan i
Endosulfan II
Endosulfan sulfate
Endothall
Endrin
Endrin Aldehyde
Endrin ketone
Epichlorohydrin
Epinephrine
Ethoxyethanol, 2-
Ethyl acetate
Ethyl carbamate .
Ethyl cyanide (propionitrile)
Ethyl ether „...
0.024
057
8
0.024
1
0.0037
15
0.00016
0.007
0.0035
0.29
0.42
0.024
0.024
0,62
0.024
0.27
0.12
0.0028
0.0049
0.0049
0.000059
15
190
(')
15
29
78
0.028
0.16
4
0.034
880
0.017
(1)
0)
0.27
0.29
0.17
0.002
0.042
15
0.16
0.013
0.0069
6
0.0069
0.0069
0.0069
(')
0.073
0.0069
0.0069
0.34
D
15
390
15
0.16
27
140
1200
530000
140
650
1
8400
110
59
20
46000
130000
140
140
770
140
12000
180
68
65
62
0.048
6900
19000
0)
6900
7
3
88
51
24000
(1)
90000
60
42
42
450
1400
420
21000
71
12000
51
58
6
150
6
6
6
0)
27
6
6
96
(')
6900
600000
6900
51
260000
0.054
0.068
8
0.054
1
0.0036
45
0.00021
0.011
0.054
0.39
0.56
0.054
0.054
0.76
0.054
0.37
0.055
0.0038
10000
10000
36
37
220
37
4
110
, 0)
0.038
n
0)
o)
0.37
5
0.045
100
0.022
0.37
0.39
0.22
0.1
0.058
15
0.37
120
(1)
4
4
4
4
4
4
880
4
4
47000
(')
53
510
37
0.37
37
0.023
0.081
15
0.023
0.056
0.0037
15
0.00016
0.00016
0.00059
2
3
0.023
0.023
0.62
0.023
2
0.023
0.0028
0.0049
0.0049
0.000059
15
190
0)
(')
15
29
78
(')
0.028
0)
0)
(')
0.16
4
0.034
230
0.017
0)
0)
0.27
0.29
0.17
0.002
0.042
15
0.16
0.013
0)
0.0069
6
0.0069
0.0069
0.0069
(')
0.073
0.0069
0.0069
0.34
15
390
15
0.16
27
140
1200
530000
140
650
1
8400
110
59
20
46000
130000
140
140
770
140
12000
180
68
65
62
0.048
6900
19000
0)
0)
6900
7
3
0)
88
(')
(')
0)
51
24000
(1)
90000
60
42
42
450
1400
420
21000
71
12000
51
58
(')
6
150
6
6
6
0)
27
6
6
96
6900
600000
6900
51
260000
0,053
0.06
32
0.053
0.06
0.0036
45
0.00021
0.00021
0.00077
2
4
0.053
0.053
0.76
0.053
2
0.011
0.0038
10000
10000
36
37
220
(')
37
4
110
0.038
y
m
0.37
5
0.045
25
0.022
0)
0)
0.37
0.39
0.22
0.1
0.058
15
0.37
120
3
4
3
3
3
3
770
3
3
47000
0)
53
510
37
0.37
37
fl?
a,
-------
TABLE A.—MODELED OR EXTRAPOLATED RISK-BASED -CONDITIONAL EXIT LEVELS—Continued
: -; CAS NO. i ;
97-63-2
62-50-0
100—41—4
106-93-4
75-21-8
96-45-7
151 56-4
52-85-7
64Q-19-7
62-74-8
206-44-0 .
86-73-7
1 6984-48-8
50-00-0
64-18-6
765-34-4
319-86-8
76-44-8
1024-57-3
87-68-3
118-74-1
319-84-6
319-85-7
58-89 9
77-47-4
67-72-1 ..
70-30-4
1888-71-7
757-58-4
591-78-6
302-01-2
193-39-5
74-88-4
78-83-1
465-73-6 .
78-59-1
120-58-1
143-50-0
303-43-4 .
7439-92-1
108-31-6
123-33-1 .
109-77-3
148-82-3
7439-97-6 .
126-98-7
74-93-1 .
67-561
91-80-5
16752-77-5
72-43-5
74-83-9
74-87-3
78-93-3
1338-23-4
60-34-4
108-10-1
-;l • : " Name
Ethyl methanesulfonate
Ethylene Dibromide . .
Ethylene oxide
Ethylene thiourea
Famphur
Fluoracetamide 2-
Fluoracetic acid sodium salt .-.
Fluoranthene
Fluorene . .
Formaldehyde ... ...
Glycidylaldehyde
HCH delta-
Heptachlor . .
Heptachlor epoxide
Hexachlorobenzene
Hexachlorocyclohexane alpha- (alpha-BHC) . ...
Hexachlorocyclohexane beta- (beta-BHC) . .....
Hexachloroethane ,
Hexachlorophene . ... . .
Hexachloropropene ... . .
Hexaethyl tetraphosphate ....
Hexanone 2- . . ...
Hydrazine ... . .
lndeno(1 2 3-cd) pyrene • ... . .
lodomethane . . . . - ....
Isodrin . .
Isophorone ... .
Isosafrole
Kepone ,
Lasiocarpine
Lead . . . . ...
Maleic hydrazide
Malononitrile . .
Melphalan
Mercury ... . ...
Methacrylonitrile
Methanethiol . . ... ...
Methanol • ....
Methapyrilene . . .
Methomyl
Methy bromide (Bromomethane)
Methyl ethyl ketone . . . ...
Methyl hydrazine ...
Methvl isobutvl ketone '.
MCL benchmark option
Wastewater
Totals
(mg/l)
24
0.0055
8
0.00093
15
«
(1)
o
«
(1)
28
22
(1)
270
(1)
0.0069
(1)
0.00053
0.0079
t1)
0.00014
0.00044
0.00078
0.0052
0.049
(1)
0.27
(1)
8
(1)
0.0029
0.024
39
(1)
0.53
• 15
(1)
(1)
30
(1)
0.16
0.16
(')
0.06
0.016
(1)
78
0.16
0)
7
0.37
0.096
78
(1)
(1)
8
Nonwastewater
Totals
(mg/kg)
100000
(1)
0.06
6900
n
0)
6
n
(1)
21000
90000
54
680000
(')
6
• 8
. 0.56
290
0.27
0.18
0.64
0.75
1500
890
(1)
1200
(1)
38000
51
4
140
120000
6
2000
6900
n
(1)
1600
6900
51
51
(1)
39
72
(1)
310000
51
6
280
850
91
250000
(1)
n
38000
Leach
(mg/l)
27
99000
9
0.0049
37
n
t1)
4
(1)
(')
2
7
37
370
(1)
4
1900
0.0069
0.018
2
0.0009
26
0.11
0)
0.068
(')
22
(1)
n
0.054
53
4
0.69
37
O
«
41
(1)
0.37 .
0.37
(1)
0.081
0.021
. n
110
0.37
4
4
110
0)
(1)
11
Toxicity benchmark option
Wastewater
Totals
(mg/l)
24
0.0055
39
0.00036
15
(')
(')
c)
(')
(1)
28
22
(1)
270
(')
0.0069
(1)
0.00053
0.0079
(1)
0.00014
0.00044
0.00078
0.0052
0.049
(1)
0.081
(')
8
0)
0.0029
0.023
39
(1)
0.53
15
(')
(1)
30
(')
0.16
0.16
(1)
0.3
0.016
(')
78
0.16
(')
7
0.37
0.096
78
t1)
(1)
8
Nonwastewater
Totals
(mg/kg)
100000
(1)
0.06
6900
(')
(1)
6
(1)
(1)
21000
90000
• 54
680000
(1)
6
8
0.56
290
0.27
0.18
0.64
0.75
1500
890
O
1200
(1)
38000
51
4
140
120000
6
2000
6900
(1)
t1)
1600
6900
51
51
(1)
• 39
72
n
310000
51
6
280
850
91
250000
(1)
(1)
38000
Leach
(mg/l)
27
99000
42
0.000098
37
n
n
3
n
o
2
7
37
370
(1)
3
10
0.0069
(1)
2
0.0009
9
0.11
(')
0.06
n
22
(1)
t1)
0.053
53
3
0.69
37
(1)
D
41
(1)
0.37
0.37
(')
0.4
0.021
n
110
0.37
3
4
110
(1)
(1)
11
OS
01
00
CD
I
I
O
OJ
p
Z
H
d
CD
O
CD
I
1-1
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CD
en
O
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CD
CX
CD
CO
-------
80-62-6
66-27-3,
91-57-6,
298-00-0...
75-55-8...... -
56-49-5
74-95-3
75-09-2
101-14-4
70-25-7 ...........
56-04-2
50-07-7
7439-98-7
91-20-3 .....
130-15-4
86-88-4
134-32-7
91-59-8
7440-02-0
54-11-5
88-74-4
99-09-2
100-01-6
98-95-3
55-86-7
51-75-2
126-85-2
302-70-5
55-63-0
99-55-8
88-75-5
100-02-7
79-46-9
56-57-5
55-18-5
62-75-9 ....:
924-16-3
10595-95-6
1116-54-7
621-64-7
86-30-6
4549CMO-0
59-89-2
759-73-9
684-93-5
100-75-4
930-55-2
13256-22-9
103-85-5
1615-80-1
152-16-9
20816-12-0
297-97-2
126-68-1
123-63-7
56-38-2
608-93-5
76-01-7
82-68-8
87-86-5
62-44-2
85-01-8 .."...".'.
108-95-2
62-38-4
25265-76^3
108-45-2
Mothyl molhacrylata ........
Methyl motnanesutronata.
Methyl naphthalene, 2- ~,
Methyl parathton ™_—™
MethylazIrkJino. 2-,
MsthyfchoJanthrene, 3-
Methylena bromide
Methytene chloride ....
Methylenebts, 4,4- (2-chtoroanIne)
Me'thyl-nftro-nitrosoguanldlfie (MNNG)
Methyllhfouracil —
Mitomydfi C
Molybdenum
Naphthalene
Naphthoquinone, 1,4-
Naphthyl-2-lhiourea, 1-
Naphttiylamine, 1-
Naphlhylamine, 2-
Nickel
Nicotine and salts
Nitroaniline, 2-
Nitroaniline, 3-
Nitroanfline, 4-
Nitrobenzene
Nitrogen mustard
Nitrogen mustard hydrochloride salt
Nitrogen mustard N-Oxide
Nitrogen mustard N-Oxide, HCI salt
Nitroglycerine
Nitro-o-toluidine, 5-
Nitrophenol, 2-
Nitrophenol, 4-
Nitropropane, 2-
Nitroquinoline-1-oxide, 4-
Nitrosodiethylamine
Nitrosodimethylamine
Nitrosgdi-n-butylamine .-...
Nitrosomethylethylamine
N-Nitrosodiethanolamine
N-Nitrosodi-n-propylamine
N-Nitrosodiphenylamine
N-Nitrosomethyl vinyl amine
N-Nitrosomorpholine
N-Nitroso-N-ethylurea
N-Nitroso-N-methylurea
N-Nitrosopiperidine
N-Nitrosopyrrolidine
N-Nitrososarcosine
N-Phenylthiourea
N,N-Diethylhydrazine
Octamethylpyrophosphoramide
Osmium tetroxide
O,O-Diethyl O-pyrazinyl phosphorothioate
O,O,O-Triethyl phosphorothioate
Paraldehyde
Parathion
Pentachlorobenzene
Pentachloroethane
Pentachloro- nitrobenzene (PCNB)
Pentachlorophenol
Phenacetin ,
Phenanthrene
Phenol
Phenyl mercuric acetate
Phenylenediamines (N.O.S.)
Phenylenediamine, m-
28
0.12
C)
0.66
0)
0)
0.029
0.039
C)
2
14
15
0)
0.16
0.16
4
0.16
0)
(1)
0.028
0.084
0)
0)
(')
0)
(1)
0.028
0.025
0.16
C)
(1)
C)
0)
0.2
(1)
0.16
(1)
0.16
0)
0.27
0)
0.12
0.12
8
3
5
0.024
0.27
0.002
15
(,)
84
(1)
0.16
0.78
100000
590
4
6
(')
0)
21000
720
C)
C)
C)
0)
1200
430000
6900
0)
51
51
8600
51
88
88
88
520
0)
(')
0)
(1)
0)
'88
42
42
3
51
(1)
0)
1
0.035
O
0.22
3600
(')
51
(1)
51
(')
0.36
0)
31
(')
590
590
38000
19
2300
140
140
22
6900
4
390000
(1)
51
1700
33
24
C)
110
C)
C)
0.037
0.09
0)
0)
C)
C)
2
15
37
C)
0.37
0.37
6
0.37
C)
C)
0.038
0.11
C)
C)
C)
(1)
C)
0.038
0.034
0.37
C)
C)
t1)
(1)
0.24
(1)
0.37
(')
0.37
C)
C)
n
0.37
C)
24
24
22
160000
0.054
0.054
C)
0.0022
37
C)
110
C)
0.37
1
28
0,12
C)
0.66
C)
C)
2
0.039
C)
C)
C)
C)
2
14
15
C)
0.16
0.16
11
0.16
C)
C)
0.028
0.084
C)
0)
C)
(1)
t1)
0.028
0.025
(1)
n
0.16
(1)
D
C)
C)
(1)
C)
02
0)
0.16
C)
0.16
0.27
C)
0.12
0.12
,8
3
5
0.023
0.081
fl.002
15
«
84
C)
0.16
0.78
100000
590
4
6
C)
C)
21000
720
C)
C)
(')
C)
1200
430000
6900
(1)
51
51
8600
51
88
88
88
520
C)
(1)
n
88
42
42
3
51
C)
t1)
1
0.035
C)
0.22
3600
(1)
51
O
51
(1)
0.36
(1)
C)
n
31
0)
590
590
38000
19
2300
140
140
22
6900
4
390000
(1)
51
1700
33
24
{')
110
C)
C)
0.19
0.053
C)
C)
C)
C)
2
15
37
C)
0.37
0.37
14
0.37
C)
n
0.038
0.11
t1)
n
0.038
0.034
C)
0.37
C)
n
0.24
(1)
0.37
(1)
0.37
(1)
O
C)
C)
n
0.37
t1)
24
24
22
160000
0.054
0.053
(1)
0.0022
37
C)
110
(1)
0.37
1
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CO
U1
O
CO
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TABLE A.—MODELED OR EXTRAPOLATED RISK-BASED CONDITIONAL EXIT LEVELS—Continued
:."'.'CASNo.
106-50-3
298-06-2
298-06-6
3288-58-2
•2953-29-9
85-44-Q
109-06-8 .
1336-36-3 .
12305-58-^5
1120-71-4
107-10-8
51-52-5
107-19-7
129-00-0 ....
110-86-1 ... .
50-55-5
108-46-3
81-07-2
94-59-7
7782-49-2 . .. .
7440-22-4
18883-66-4 .. .
57-24-9
10-42-5 .. .
18496-25-8 .
1746-01-6 .. . .
95-94-3
630-20-6
79-34-5 . .
127-18-4..
58-90-2
107-49-3
107-49-3
3689-24-5
7440-28-0
62-55-5 ....:..;
39196-18-4
108-98-5
79_19_6 .
62-566 „
137-26-8
7440-31-5 .
108-88-3
584-84-9
95-80-7
823-40-5
496-72-0 . .
636-21-5
95-53-4
106-49-0
8001-35-2
76-13-1
120-82-1
71-55-6
79-00-5
.••«•.•"' i.i, sr
.....--., Name
Phenylenediamine p-
Phorate . .
Phosphorodithioic acid, dimethylethylester
Phosphorodithioic acid o-o-diethyl ester
Phosphorodithioic acid, trimethyl ester , : .....
Phthaiic anhydride ...: .....
Picoline 2-
Polychlorinated biphenyls . .
Pronamide .....
Prbpylthiouracil
Pyrene ..... ... . .
Pyridine . . .
Reserpine
Resorcinol
Saccharin and salts .'.
Safrole
Selenium . ... ... . .•
Silver . . ...
Streptozotocin ... .
Strychnine ... .
Stryene . •
Sulfide ... .... . .
TCDD 2,3,7,8-
Tetrachlorobenzene 1 2 4,5-
Tetrachloroethane 1112-.. .
Tetrachloroethane 1 1 2 2- . . . . ...
TetrachloroGthylene
Tetrachlorophenoi; 2,3,4,6-
Tetraethyl pyrophosphate
Tetraethyl pyrophosphate . . ...
Tetraethyldithiopyrophosphate . ...
Thallium (I)
Thioacetamide :
Thiofanox ... . . .
Thiophenol .... ... . . ....
Thiosemicarbazide
Thiourea
Thiram .
Tin .
Toluene ; . . .
Toluene diisocyanate ... .
Toluenediamine 2 4 —
Toluenediamine, 2,6-
Toluenediamine 3 4-
Toulidene,3,4- ,.
Toluidine o- .... ....
Toiuidine p-
Toxaphene ...
Trichloro-1 ,2,2-trifuoroethane, 1 ,1 ,2 :.
Trichlorobenzene, 1,2,4-
Trichloroethane 1 1,1- .
Trichloroethane, 1 .1 .2-
MCL benchmark option
Wastewater
Totals
(mg/l)
0.16
0.11
{i)
(')
«
D
(')
0.16
See
Table B
21
(')
0.16
0.12
39
54
0.16
0.16
(')
(1)
0.0035
0.23
200
(1)
0.045
0.91
(1)
0.23
0.024
0.0037
0.026
2
(1)
(')
0.23
0.035
(1)
0.12
0.12
(1)
(')
(1)
(1)
6
(1)
(1)
0.16
• 0.16
0.16
(1)
0)
0)
0.77
0.69
74
0.012
Nonwastewater
Totals
(mg/kg)
51
510
(1)
(1)
(1)
(')
9600
51
0.25
230000
(')
51
590
130000
16000
930
51
0)
(1)
28
280
9
(1)
(')
(1)
1600
370
70
100000
35000
6900
6900
1200
33
(1)
590
590
(1).
(')
(')
(1)
560000
(') '
(')
51
51
51
(')
(1)
(')
62000
630000 '
190 •
Leach
(mg/l)
0.37
(1)
(1)
(')
(')
(1)
0.37
0.009
25
(')
0.37
24
53
2
0.21
0.37
4
0)
0.0044
0.12
(1)
- 0.059
1
0)
0.032
0.042
0.0077
0.032
2
(')
0)
0.048
(')
24
24
(')
(1) '
(')
(')-
7
(1)
(')
0.37
0.37
0.37
(1)
(1)
160
0.84
3
0.054
0.039
Toxicity benchmark option
Wastewater
Totals
(mg/l)
0.16
0.11
(1) .
(')
(')
(1)
(1)
0.16
See
TableB
21
(')
0.16
0.12
39
54
0.16
0.16
(')
(')
0.0035
0.93
200
0)
0.045
64
(')
0.23
0.024
0.0037
2
2
(')
T)
0.23
0.05
f1)
0.12
0.12
(1)
(1)
(1)
(1)
30
n
0.16
0.16
0.16
(1)
(')
(1)
2200
0.69
74
0.007
Nonwastewater
Totals
(mg/kg)
51
510
(1)
(1)
(')
(1)
9600
51
0.25
230000
(1)
51
590
130000
16000
930
51
n
(1)
28
280
9
n
(1)
(')
1600
370
70
100000
35000
6900
6900
1200
33
(')
590
590
(1)
D
(1)
(')
560000
(')
51
51
51
• (1)
(1)
(1)
62000
630000
190
Leach
(mg/l)
0.37
(1)
(1)
(')
(')
(')
0.37
0) .
25
(')
0.37
24
53
2
0.21
0.37
(1)
0.0044
1
• n
0.059
70
(')
0.032
0.042
0.0077
3
2
(1)
(1)
0.071
(1)
24
24
(1)
(1)
(1)
. (1)
51
(1)
0.37
0.37
0.37
(')
(')
3
12000
3
0.054
0.0077 .
en
05
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Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66461
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66462 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
TABLE B.—QUANTITATION-BASED CONDITIONAL EXIT LEVELS
CAS No.
208—96—8
75-36-5
591-08-2
107 02 8
79-06-1
107-13-1
1402-68-2
1 1 6-06-3
309-00-2
107 18-6
2763-96-^t
504-24-5
61-82 5
120-12-7
7440-38-2
2465-27-2
115-02-6
92-87-5
98-07-7
50-32-8
205-82-3
207-08-9
191-24-2
56-55-3
225-51-4
542-88-1
357-57-3 . .
86-74-8
353-50-4
75-87-6
305-03-3
57 74-9
494—03—1
107-20-0
110-75-8
107-30-2
5344-82-1
542-76—7
6358-53-8
7440-48-4
57 12 5
14901-08-7 ....
108-94-1
131_89_5
50-18-0
20830-81-3 ....
53-19-0
72-55-9 . .
3424-82-6
50-29-3
789-02-6
192-65-*
189-64-0
189-64-9
194-59-2
226-36-8
53-70-3
224-42-0
311-45-5
56-53-1
77-78-1
119-93-7
57_g7_e
Name
Acenaphthylene
Acetyl chloride
Acetyl-2-thiourea
Acrylonitrile
Allyl alcohol
Aminomethyl-3-
isoxazolol, 5-.
Aminopyridine, 4-
Amitrole
Anthracene
Arsenic
Auramine
Azaserine
Benzidine
Benzotrichloride
Benzo(a)pyrene
Benzo(j)fluoranthene
Benzo{k)fluoranthene
Benzo[g ,h,i]perylene
Benz(a)anthracene ..
Bis(chloromethyl)
ether.
Brucine
Carbon oxyfluoride ...
Chloral
Chlorambucii . ........
Chloroacetaldehyde .
Chloroethyl vinyle
ether, 2-.
Chloromethyl methyl
ether.
Chlorophenyl thio-
urea, 1-c-.
Chloropropionitrile,
3-.
Citrus red No. 2
Cobalt
Cyclohexanone
Cyclohexyl-4,6-
dinitrophenol, 2—.
Cyclophosphamide ..
Daunomycin
ODD (o D')
DDE
DDE (o p') :.....
DDT
DDT (o D')
Dibenzo-
[a,e]ypyrene.
Dibenzo- [a,h]pyrene
Dibenzo- [a,i]pyrene .
Dibenzo-
[c,g]carbazole,
7H-.
Dibenz- (a,h)acridine
Dibenz- (a.h)ant-
hracene.
Dibenz[aj] acridine ..
Diethyl-p-nitrophenyl
phosphate.
Diethylstibestrol
Dimethyl sulfate
Dimethybenzidine,
3,3'-.
Dimethyl- benz(a)-
anthracene, 7,12-.
MCL benchmark option
Wastewater
Totals
(mg/l)
0.02
0)
1
0.013
0.01
0.008
(1)
0.05
0.000034
(1)
(1) '
(')
(1)
0.007
0)
(1)
0.0025
(1)
0)
20
0)
0)
•0)
(1)
0.00004
(1)
(1)
(1)
(1)
0)
(1)
0.2
(1)
10
0.1
(1)
(')
(1)
0.000058
(1)
0.000081
0)
(0.01
0.00003
0)
0.0078
0)
0.0033
0.00037
Nonwastewater
Totals
(mg/kg)
(')
• 0.1
(1)
0)
(1)
(1)
(1)
(')
(')
0.042
(')
(')
0) '
(1)
(1)
(1)
(1)
(1)
(')
(1)
0)
(')
(')
(1)
(1)
(')
(1)
(1)
(1)
(1)
0.084
(')
1
(')
0.7
0.039
Leach
(mg/l)
0.02
(')
0.01
0.008
(1)
0.000034
(1)
(1)
t1)
(1)
0.007
t1)
0)
0.0025
(1)
0.000013
0)
20
0)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
t1)
0.1
t1)
0.5
(1)
0.1
(1)
<')
(1)
(1)
(1)
0.01
0.00003
(1)
0.0078
n
0.0033
0.00037
Toxicity benchmark option
Wastewater
Totals
(mg/l)
0.02
0)
1
0.013
0.01
0)
0.05
0.000034
(1)
0)
(<)
(1)
0.007
0.0005
0)
(<) '
0.0025
0)
(1)
20
0)
H
(1)
(')
0.00004
(1)
(1)
(1)
(1)
(1)
0.1
(1)
0.2
(1)
10
0.1
(<)
(1)
(1)
0.000058
C)
0.000081
(')
0.01
0.00003
0)
0.0078
«
0.0033
0.00037
Nonwastewater
Totals
(mg/kg)
0)
0.1
0.008
(1)
(1)
(1)
(1)
D
(1)
(1)
0.042
n
(1)
(1)
(1)
0)
(1>
t1)
o
f1)
0)
o)
«
o
D
t1)
D
o
«
«
(1)
n
0.084
(1)
1
t1)
0.7
0.039
Leach
(mg/l)
n
0.01
0)
0.000034
n
(1)
D
D
0.007
(1)
(1)
0.0025
(1)
0.000023
0.0002
0.0002
0.0008
0.000013
0.0005
(1)
20
(1)
(1)
(')
(1)
0)
(1)
(1)
(1)
(1)
0.1
0)
(1)
D
0.1
«
(1)
(1)
(1)
(1)
0.001
0.0002
0.0002
0.01
0.0002
0.00003
0.001
0)
0.0078
(1)
0.0033
0.00037
-------
Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66463
TABLE B.—QUANTITATION-BASED CONDITIONAL EXIT LEVELS—Continued
CAS No.
70-44-7
119-90-4
100-25-4
534-52-1
541-53-7
145-73-3
51-43-4
62-50-0
86-45-7
151-56-4
52-85-7
640-19-7
62-74-8 .....
16984-48-8 ....
50-00-0
765-34-4
76-44-8
118-74-1
70-30-4
757-58-4
302-01-2
193-39-5
465-73-6
143-50-0
303-43-4
108-31-6
148-82-3
74-93-1
16752-77-5 ....
1338-23-4
60-34-4
91-57-6
75-55-8
56-49-S
101-14-4
70-25-7
56-04-2
50-07-7
88-88-4
88-74-4
99-09-2
55-86-7
51-75-2
126-85-2 ........
302-70-5
55-63-0
110-02-7
79-46-9
55-18-5
62-75-9
924-16-3
10595-95-6 ....
1116-54-7
621-64-7
Name
Dimelhylcarbamoyl
chloride.
DImethy- oxyben-
zidlne, 3,3'-.
Dinilrobenzene, 1,4-
Dlnitro-o-cresol, 4,6-
Dithiobluret
Endothall
Epinephrine
Ethyl
melhanesulfonate.
Ethylene thiourea
Ethylenetmine
(azlrldine).
Famphur
Fluoracetamkte, 2- ...
Fluoracetfe add, so-
dium salt.
Fluoride
Fomiakiehyde
GlycWyfaktehyde
Heptachlor
Hexachlorobenzene .
Hexachlofophene
Hexaethyl
tetraphosphate.
Hydrazine
lndenof.1,2.3-
cdejpyrene.
Isodrin
Kepone
Matefe anhydride
Melphalan
Methanethlol
Methomyl
Methyl ethyl ketone
peroxide.
Methyl hydrazlne
Methyl naphthalene,
2-.
Methylaziridine, 2- ....
Methylcholanthrene,
3-.
Methylenebis. 4,4'-
(2-chloroaniline).
Methyhiitro-
nilrosoguanldine
(MNNQ).
Melhyllhiouracil
Naphlhyl-2-thiourea,
1-.
Nitroaniline, 2-
Nilroaniline, 3-
Nitrogen mustard
Nitrogen mustard hy-
drochtoride salt.
Nitrogen mustard N-
Oxtde.
Nitrogen mustard N-
Oxide, HCI salt.
Nitroglycerine
N'rtrophenol, 4-
Nitropropane, 2-
NHrosodlethylamine .
Nitrosodimethylamine
Nitrosodi-n-butyl-
amine.
Nitrosomelhylethyla-
mine.
N-
Nitrosodlelhanola-
mlne.
N-Nitrosodi-n-
propyamine.
MCL benchmark option
Wastewater
Totals
(mg/l)
0)
0.04
0.05
(1)
0.1
(1)
(')
(1>
0.02
(1)
(')
0.023
(')
0.00004
0.0016
0.21
0)
0)
0.02
0.016
(')
(1)
(')
0)
0.05
(')
0)
0.01
(')
0.01
(1)
(1)
(')
(')
0)
0.05
0.05
o
(1)
(1)
(')
(')
0.05
0.0058
0.002
0.0006
0.06
0.028
0.01
0.026
Nonwastewater
Totals
(mg/kg)
t1)
7
t1)
0)
(')
0.018
(')
(')
(')
V)
(1)
2
(1)
0.097
(1)
(')
0)
(1)
(1)
(1)
0.046
(')
(1)
(1)
(1)
(1)
(1)
(')
(1)
(1)
(')
(1)
0.074
0.7
Leach
(mg/l)
0)
0.04
0.05
0)
f1)
0)
0)
(1)
(1)
(1)
0.21
t1)
(1)
0.000043
0.016
f1)
(1)
(1)
(')
0)
(1)
0.01
t1)
0.01
0)
0)
(1)
0)
(')
0.05
0.05
(')
0)
(')
t1)
0)
0.05
0.002
0.0006
0.06
0.028
0.01
0.026
Toxicity benchmark option
Wastewater
Totals
(mg/l)
(')
0.04
0.05
0)
0.1
(')
(')
(1)
0.02
(1)
(')
0.023
0)
0.00004
0.0016
0.21
0)
n
0.02
0.016
(')
(1)
(')
(1)
0.05
(1)
(')
0.01
O
0.01
(')
(1)
(1)
(')
n
0.05
. 0.05
(1)
(1)
(1)
(')
(1)
0.05
0.0058
0.002
0.0006
0.06
0.028
0.01
0.026
Nonwastewater
Totals
(mg/kg)
«
7
(1)
(1)
t1).
0.018
(1)
(1)
0)
n
(1)
2
(')
0.097
(')
0)
n
(')
(1)
(1)
0.046 '
(1)
(')
(1)
(!)
(1)
(1)
(1)
(')
(1)
(1)
1
0.074
0.7
Leach
(mg/l)
(1)
0.04
0.05
(')
n
(1)
n
n
n
(1)
0.0016
0.21
(1)
(')
0.000043
0.016
(1)
(')
(1)
(1)
t1)
(')
0.01
(1)
0.01
(1)
(1)
I1)
(1) •
<1)
0.05
0.05
(')
(1)
(1),
(1)
(1)
0.05
"' 0.002
'.'.•' '0.0006
- .,.,0-QS
'.! ' 0.028
0.01
;'0.026
-------
66464 Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
TABLE B.—QUANTITATION-BASED CONDITIONAL EXIT LEVELS—Continued
CAS No.
4549-40-0
759-73-9
615-53-2
16543-55-8 ....
100-75-4
930-55-2
13256-22-9 ....
103-85-5
1615-80-1
20816-12-0 ....
82-68-8
85-01-8
62-38-4
298-06-6
3288-58-2
2953-29-9
85-44-9
1336-36-3
1120-71-4
108-46-3
81-07-2
18883-66-4 ....
57-24-9
1746-01-6
107-49-3
62-55-5 . ...
79-1 g_6
62-56-6
137-26-8
7440-31-5
584-84-9
95-80-7
95-53-4
106-49-0
8001-35-2
75-70-7
126-72-7
52-24-4
72-57-1
66-75-1
75-01-4
81-81-2
Name
N-Nitrosomethy vinyl
amirie.
N-Nitroso-N-
ethylurea.
N-Nitroso-N-
methylurethane.
N-Nitrosonornicotine
N-Nitrosopiperidine ..
N-Nitrosopyrrolidine .
N-Nitrososarcosine ..
N-Phenylthiourea
N ,N-Diethylhydrazine
Osmium tetroxide
Pentachloronitroben-
zene (PCNB).
Phenanthrene
Phenyl mercuric ace-
tate.
Phosphorodithioic
acid,
dimethylethylester.
Phosphorodithioic
acid, o-o-diethyl
ester.
Phosphorodithioic
acid, o-o-diethyl-s-
methlyl.
Pyhosphorodithioic
acid, trfmethyl
ester.
Phthalic anhydride ...
Polychlorinated
biphenyls.
Propane sultone,
1,3;.
Resofcinol
Saccharin and salts .
Strychnine
TCDD, 2, 3, 7.8-
Tetraethyl
pyrophosphate.
Thioacetamide
Thiosemicarbazide ...
Thiourea
Thiram
Tin
Toluene diisocyanate
Toluenediamine, 2,4-
Toluidine, 0-
Toluidine, p-
Toxaphene
Trichloromethanethiol
Tris (2, 3-
dibromopropyl)
phosphate.
Tris (1-azridinyl)
phosphine sulfide.
Trypan blue
Vinyl chloride
Warfarin
MCL benchmark option
Wastewater
Totals
(mg/l)
(')
(1)
(')
(')
0.0014
0.0047
0)
(')
(')
3
0.006 '
0)
(')
(')
(')
(1)
(1)
0.0005
'(')
0.1
(')
(1)
1.000E-08
0)
1
(')
0)
0.05
8
0)
0.013
0.012
0.017
0.0013
(')
0.025
(1)
0)
(1)
0.05
Nonwastewater
Totals
(mg/kg)
(1)
(1)
(1)
(1)
0.033
(1)
(1)
0)
200
(1)
(')
(1)
(1)
(1)
(1)
7
(1)
(1)
3
(1)
0)
(')
500
1
0.03
(')
(')
(')
(')
Leach
(mg/l)
(')
(')
(1)
(1)
0.0014
0.0047
(')
(')
(')
3
0.02
0.006
(')
0)
(1)
(')
«
(')
(')
0)
(').
(')
1
. (1)
0)
8
0)
0.013
0.012
0.017
0)
0.025
(')
<1)
(1)
Toxicity benchmark option
Wastewater
Totals
(mg/l)
<1)
(1)
(')
0)
0.0014
0.0047
(')
(1)
(')
3
0.006
(1)
0)
(')
o)
, (1)
(1)
0.0005
(1)
0.1
(1)
(1)
1.000E-08
0)
1
t1)
(1)
0.05
8
(1)
0.013
0.012
0.017
0.0013
«
0.025
(1)
(1)
(')
0.00017
0.05
Nonwastewater
Totals
(mg/kg)
(') D(')
(1)
n
(')
0.033
0) '
0)
(')
200
(1)
(1)
(1)
0
0)
(')
7
(')
(')
. 3
(1)
n
o
500
1
0.03
0
(1)
(1)
(1)
Leach
(mg/l)
, (1)
(1)
(1)
0.0014
0.0047
(1)
D
(')
3
0.02
0.006
(1)
(1)
(')
(1)
(1)
0)
0.0005
«
(1)
(')
1.000E-08
(')
1
(1)
0)
8
(')
0.013
0.012
0.017
(1)
0.025
(')'
(1)
(1)
1 No testing required; additional LDR requirements apply.
PART 266—STANDARDS FOR THE
MANAGEMENT OF SPECIFIC
HAZARDOUS WASTES AND SPECIFIC
TYPES OF HAZARDOUS WASTE
FACILITIES
9. The authority citation for part 266
continues to read as follows:
Authority: 42 U.S.C. 6905, 6912(a), 6924,
and 6934.
10. Section 266.2Q is amended by
revising the first sentence of paragraph
fb) to read as follows:
(b) Products produced for the general
public's use that are used in a manner
that constitutes disposal and that
contain recyclable materials are not
presently subject to regulation if, for
each hazardous constituent in each
recyclable material (i.e., hazardous
waste) that they contain, they meet the
-------
Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules '66465
applicable exit levels in appendix X to
Part 261 of this chapter. * * *
PART 268—LAND DISPOSAL
RESTRICTIONS
11. The authority citation for part 268
continues to read as follows:
Authority: 42 U.S.C. 6905,6912(a) 6921,
and 6924.
12. Section 268.2 is amended hy
adding paragraph (j) to read as follows:
* * * * *
(j) Land treatment means waste is
applied onto or incorporated into the
soil surface.
13. Section 268.40 is amended by
revising the first sentence of paragraph
(a), revising paragraph (e), and adding
paragraph (g) to read as follows:
§268.41 Applicability of treatment
standards
(a) Except as provided in paragraph
(g) of this section, a waste identified in
the table "Treatment Standards for
Hazardous Wastes" may be land
disposed only if it meets the
requirements found in the table. * * *
(e) Except as provided in paragraph
(g) of this section, for all characteristic
wastes (D001, D002, and D012-D043)
that are subject to treatment standards
in the following table "Treatment
Standards for Hazardous Wastes," all
underlying constituents (as defined in
§ 268.20(i)) must meet Universal
Treatment Standards, found in § 268.48,
Table UTS, prior to land disposal.
*****
(g) Wastes subject to either the
treatment standards described in
paragraph (a)(l) or (a)(2) of this section
or the Universal Treatment Standards
described in paragraph (e) of this
section may be land disposed if they
meet either of the alternative, risk-based
standards found in subpart F and G of
this part and representing levels at
which threats to human health or the
environment are minimized.
14. Part 268 is amended by adding
Subpart F consisting of § 268.60 to read
as follows:
Subpart F—Minimize Threat Levels
Without Management Requirements
§ 268.60 Minimize threat levels.
(a) Table "Minimize Threat Levels"
identifies risk-based standards
representing levels at which threats to
human health and the environment are
minimized. These levels may be used as
alternatives to waste-specific treatment
standards in the table to § 268.40 and to
the Universal Treatment Standards in
the table to § 268.48. Nonwastewaters
must meet both the total and waste
extract levels contained in the table of
"Minimize Threat Levels".
(b) Wastes identified in the Table to
§ 268.40 may be land disposed if they
meet either the requirements in that
Table or the standards in the Minimize
Threat Table for all constituents.
Characteristic wastes that are subject to
the requirement for meeting Universal
Treatment Standards under § 268.40(e)
must also meet the requirements of
Table UTS or the Minimize Threat Table
for all underlying hazardous
constituents as defined in § 268.2(i).
(c) Wastes containing either regulated
hazardous constituents under the Table
to § 268.40 or UTS constituents which
do not have treatment standards listed
in the Minimize Threat Table must
continue to comply with treatment
standards for these constituents in the
tables to § 268.40 or § 268.48 prior to
land disposal.
268.60 TABLE 1 .—MINIMIZE THREAT LEVELS
CAS
83-32-9
67-64-1
75-05-8
98-86-2
107-05-1
7440-39-3 .
71-43-2
117-81-7
75-27-4
75-25-2
71-36-3
88-85-7
85-68-7
75-15-0
56-23-5
126-99-8
106-47-8 .
108-90-7 ...
124-48-1
67-66-3
95-57-8
218-01-9
108-39-4
95-48-7
106-44-5
84-74-2
117-84-0 ....
95-50-1
106-46-7
75-71-8
75-34-3
156-60-5
120-83-2 ..
94-75-7
84-66-2
131-11-3 ...
Constituent name
Acenaphthene
Acetone
Acetonitrile
Acetophenone
Allyl chloride
BIs(2-ethylhexyl)phthalate •
Bromoform (Tribromomethane)
Butanol
Butyl-4 6-dinitrophenol 2-sec- (Dinoseb)
Carbon disulfide
Carbon tetrachloride
Chlorc— 1 3-butadiene 2- (Chloroprene) .
Chlofoaniline, p-
Chlorobenzene
Chlorodibromomethane
Chlorophenol, 2-
Chrysene
Cresol m- ....
Cresol, c-
Cresol, p-
Di-n-butyl phthalate .
Di-n-octyl phthalate
Dichlorobenzene 1 2- .
Dichlorobenzene, 1 ,4- .-.
Dichlorodifluorornethane ,
Dichloroethane, 1 ,1 - ;.
Dichloroethylene trans-1 2-
Dichlorophenol, 2,4-
Dichlorophenoxyacetic acid, 2,4- (2,4-D)
Diethyl phthalate
Dimethvl ohthalate
WW standard
(man
31
16
17
33
16
0.19
240
0.52
2
0.9
0.1
8
8
0.84
230
15
15
3
0.62
2
190
78
NWW standard
(mg/kg)
9500
17000
920
1200
260
2100
110
230
19
170
18000
770
87
330
9
290
140
2500
28
7
100
35
22000
27000
2600
90000
4500
50000
64
8100
24
14000
770
3100
4500
NWW standard
(mg/l)
5
6
0.3
6
16
0.0054
0.001 1 .
0.0025
0.018
6
0.064
64
6
0.0016
0.16
1
0.0018
0.017
0.32
0.0012
3
3
0.32
25
0.1
• 6
0.011
12
0.00006
1
0.18
0.6
54
-------
66466 Federal Register,/ Vol. 60,, No. 245 / Thursday, December 21, 1995 /Proposed Rules
268.60 TABLE 1 .—MINIMIZE THREAT LEVELS—Continued
CAS
105-67-9
51-28-5
121-14-2
606-20-2
122-39-4
298-04-4
72-20-8
141-78-6
60-29-7
97-63-2
100-41-4
206-44-0
86-73-7
76-44-8
87-68-3
319-85-7
58-89-9
77-47-4
67-72-1
78-83-1
7439-92-1 ...
7439-97-6 ...
67-56-1
72-43-5
74-83-9
74-87-3
78-93-3
108-10-1
80-62-6
298-00-0
74-95-3
75_09_2
91-20-3
7440-02-0 ...
98-95-3
56-38-2
608-93-5
82-68-8
108-95-2
298-02-2 .....
23950-58-5 .
129-00-0
110-86-1
7782-49-2 ...
7440-22-4 ...
95-94-3
630-20-6
79-34-5
127-18-4
58-90-2 .
7440-28-0 ...
108-88-3
76-13-1
120-82-1
71-55^-6 .
79-00-5
79-01-6
75-69-4
95-95-4
88-06-2,
93-76-5".......
93-72-1
96-18-4
7440-62-2 ...
1330-20-7 ...
7440-66-6 ...
Constituent name
Dimethylphenol, 2,4-
Dinitrophenol, 2,4-
Dinitrotoluene, 2,4-
Dinitrotoluene, 2,6-
Diphenylamine
Disulfoton :
Endrin
Ethyl acetate
Ethyl ether
Ethyl methacrylate ...
Ethylbenzene
Fluoranthene
Fluorene
Heptachlor
Hexachloro-1 ,3-butadierie .
Hexachlorocyclohexane, beta- (b<
Hexachlorocyclohexane, gamma-
Hexachlorocyclopentadiene
Hexachloroethane
Isobutyl alcohol
Lead . -
Mercury
Methanol
Methoxychlor '.
Methyl bromide (Bromomethane)
Methyl chloride (Chloromethane)
Methyl ethyl ketone
Methyl isobutyl ketone
Methyl methacrylate
Methyl parathion ,
Methylene bromide
Methylene chloride
Naphthalene '
Nickel
Nitrobenzene
Parathion ;
Pentachlorobenzene
Pentachloronitrobenzene (PCNB)
Phenol ....
Phorate
Pronamide
Pyrene
Pyridine
Selenium
Silver
Tetrachlorobenzene, 1,2,4,5-
Tetrachloroethane, 1,1,1,2-
Tetrachloroethane 1 1 ,2 2-
Tetrachloroethylene
Tetrachlorophenol 2346-
Thallium (I) ....; :
Toluene
Trichloro-1 ,2,2,-trifluoroethane, 1 ,
Trichlorobenzene, 1 ,2,4-
Trichloroethane 111-
Trichloroethane, 1,1,2-
Trichloroethylene
Trichlorofluoromethane
Trichlorophenol, 2,4,5-
Trichlorophenol, 2,4,6-
Trichlorophenoxyacetic acid, 2,4,
Trichlorophenoxypropionic acid, 2
Trichloropropane, 1,2,3-
Vanadium „...
Xylenes (total)
Zinc
3ta-BHC) .. .
(Lindane) ^
••
1,2-
5- (245-T)
,4,5- (Silvex)
WW standard
(mg/l)
4
0.27
15
0.073
390
27
24
39
28
22
0.00044
39
30
0.3
78
7
0.37
78
8
28
0.66
2
14
11
0.084
3
5
0.081
• 84
0.11
21
54
0.16
0.93
200
0;23
2
2
30 ,
2200
0.69
74
48
18
0.054
2
1
1
10
22
99
NWW standard
(mg/kg)
11000
210
86
12000
43
0.26
270000
41000
3400
550000
6000
90000
8
36
0:12
0.1
1500
81
55000
570
0.6
140000
19
500
91
110000
17000
40000
8400
310
120000
110
45
160000
160
440
16000
810
170
130
29
. .13000
6200
5
180000
3500
48000
11
570
26000
12000
120
63
870
250
170000
320
NWW standard
(mg/l)
1
0.11
0.064
3
13
32
110
11
7
8
2
3
0.0069
0.00021
0.69
0.033
15
12
0.14
30
0.92
30 .
3
8
0.19
0.015
3
5
0.032
32
6
2
0.06
0.032
0.0078
0.0077
0.68
0.58
0.019
13
1
0.054
0.0018
0.013
16
4
0.015
0.64
0.34
•4
150
38
-------
Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66467
15. Part 268 is amended by adding
subpart G consisting of §§ 268.70 and
268.71 to read as follows:
Subpart G—Conditioned Minimize
Threat Levels with Management
Requirements
§ 268.70 Conditioned Minimize Threat
Levels.
(a) Table "Conditioned Minimize
Throat Levels" identifies risk-based
standards representing levels at which
threats to human health and the
environment are minimized for wastes
which are placed in landfills or
monofills (but not land application
units). These levels may be used as
alternatives to waste-specific treatment
standards in the table to § 268.40 and to
the Universal Treatment Standards in
the table to § 268.48 for wastes which
comply with the requirements of
§ 268.71. Nonwastewaters must meet
both the total and waste extract levels
contained in the table of "Minimize
Threat Levels".
(b) Wastes identified in the Table to
§ 268.40 may be land disposed if they
meet, for all hazardous constituents
identified in the table to § 268.40, either
the requirements in that table, the
standards in the Minimize Threat Table
in subpart F, or, if they meet the
requirements in § 268.71, the standards
in the Conditioned Minimize Threat
Table. Characteristic wastes that are
subject to the requirement for meeting
Universal Treatment Standards under
§ 268.40(e) must also meet the
requirements of Table UTS, the
Minimize Threat Table, or, if they meet
the requirements of § 268.71, the
Conditioned Minimize Threat Table, for
all underlying hazardous constituents as
defined in § 268.2(1).
(c) Wastes containing either regulated
hazardous constituents under the Table
to § 268.40 or UTS constituents which
do not have treatment standards listed
in the Minimize Threat Table must
continue to comply with treatment
standards for these constituents in the
tables to § 268.40, § 268.48, or the
Minimize Threat Table to Subpart F
prior to land disposal.
268.70 TABLE 1 .—CONDITIONAL MINIMIZE THREAT LEVELS
CAS
83-32-9
67-64-1
75-05-8
98-86-2
107-05-1
62-53-3
7440-33-3 ...
71-43-2
39538-32-9 .
117_81_7
75-27-4
75-25-2
71-36-3
88-85-7
85-68-7
7440-43-9 ...
75-15-0
56-23-5
126-99-8
106-47-8 ..
108-90-7
124-48-1
67-66-3
95-57-8
7440-47-3 ...
218-01-9
108-39-4
95-48-7
106-44-5
72-54-8
50-29-3
84-74-2
117-84-0
95-50-1
106-46-7
75-71-8
75-34-3
107-06-2
156-60-5
120-83-2
94-75-7
78-87-5
10061-01-5 .
10061-02-6 .
84-66-2
131-11-3 . .
105-67-9
51-28-5
121-14-2
Constituent name
Acenaphthene
Acetone
Acetonitrile
Acetophenone
Ally! chloride
Aniline
Barium
Benzene
Bis (2-chloroisopropyl) ether
Bis(2-ethylhexyl)phthalate
Bromodichloromethane
Bromoform (Tribromomethane)
Butanol
Buthi-4 6-dinitrophenol, 2-sec- (Dinoseb) . ....
Butylbenzylphthalate
Cadmium '.
Carbon disulfide
Carbon tetrachloride .. .
Chloro-1 ,3-butadiene, 2-(Chloroprene)
Chloroaniline p-
Chlorobenzene
Chlorodi- bromo- methane
Chloroform
Chlorophenol, 2-
Chromium
Chrysene
Cresol, m-
Cresol, o-
Cresol, p-
ODD
DDT
Di-n-butyl phthalate
Di-n-octyl phthalate
Dichlorobenzene, 1 ,2-
Dichlorobenzene, 1 ,4-
Dichloro- difluoro- methane
Dichioroethane 11- .
Dichloroethane, 1,2-
Dichloro- ethylene, trans-1,2-
Dichlorophenol, 2,4-
Dichiorophen- oxyacetic acid, 2,4- (2,4-D)
Dichloropropane, 1 ,2-
Dichloropropene, cis-1 ,3-
DIchioropro- pene, trans-1,3-
Diethyi phthalate
Dimethyl phthalate . .
Dimethylphenol, 2,4-
Dinitrophenol, 2,4-
Dinitrotoluene, 2,4-
WW standard
(mg/l)
31
16
17
33
16
0.19
240
0.52
2
09
0.1
8
8
0.84
230
15
15
3
0.62
2
190
78
4
0.27
NWW standard
(mg/kg)
63000
39000
2200
75000
260
170
34000
250
97
740
240
1600
41000
6000
87
110
3800
130
1700
5800
41000
200
76
8500
16
35
30000
46000
2900
026
0.11 "
90000
21000
530000
650
8400
110
59
130000
770
12000
180
65
62
• 19000
24000
450
1400
NWW standard
(mg/l)
13
21
1
22
0.072
45
0.023
0.0088
0.001 1
0.01'1
0.081
21
0.24
67
0.32
24
0.0077
0.56
6 '
0.0079
0.075
1
2
0.0012
11'
,.. n . • .
1 -
6800
0.0054
25
0.1
32
0.06
45
0 00021
. -0.00021
. , . 4 ." ' -
.,..0.76 -
. 2 • •
.0.011
1 0000
10000
220
5 "••-•
rO.37
0.39
-------
66468 Federal Register /Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules
268.70 TABLE 1 .—CONDITIONAL MINIMIZE THREAT, LEVELS—Continued
CAS
606-20-2
122-39^
298-04-4
72-20-8
141-78-6
60-29-7
97-63-2
100-41-4
206-44-0
86-73-7
76-44-6
1024-57-3 ...
87-68-3
319-84-6
319-85-7
58-89-9
77-47-4
67-72-1
78-83-1
7439-92-1 ...
7439-97-6 ...
67-56-1
72-43-5
74-83-9
74-87-3
78-93-3
108-10-1
80-62-6
298-00-0
74-95-3
75-09-2 1
86-30-6
91-20-3
7440-02-0 ...
98-95-3
152-16-9
56-38-2
608-93-5
82-68-8
87-86-5
108-95-2
298-02-2
23959-58-5 .
129-00-0
110-86-1
94-59-7
7782-49-2 ...
7440-22-4 ...
95-94-3
630.20-6 ......
79-34-5 .......
127-18-4
53-90-2
7440-28-0 ...
108-88-3
76-13-1
120-82-1
71-55-6
79-01-6
75-69r4
95-95-4
88-06-2
93-76-5 .I..:..
93-72-1 ....:.i
96-18-4
7440-62-2 ...
1330-20-7 ...
7440-6646 ...
Constituent name
Dinitrotoluene, 2,6-
Diphenyla- mine
Disulfoton
Endrin '.
Ethyl acetate
Ethyl ether
Ethyl methacrylate
Ethylbenzene
Fluoranthene
Fluorene
Heptachlor :
Heptachlor epoxide
Hexachloro-1 ,3-butadiene
Hexachloro- cyclohex- ane, alpha- (alpha-BHC) ;
Hexachloro- cyclohex- ane, beta- (beta-BHC)
Hexachloro- cyclohex- ane, gamma- (Lindane)
Hexachloro- cyclopent- adiene
Hexachloroethane
Isobutyl alcohol
Lead
Mercury
Metnanol
Methoxychlor
Methyl bromide (Bromo- methane)
Methyl chloride (Chloro- methane)
Methyl ethyl ketone
Methyl isobutyl ketone
Methyl methacrylate
Methyl parathion
Methylene bromide
Methylene chloride
N-Nitrosodi- phenylamine
Naphthalene ...
Nickel
Nitrobenzene
Octamethyl- pyrophos- phoramide
Parathion
Pentachlorobenzene
Pentachloro- nitrobenzene (PCNB)
Pentachlorophenol ;
Phenol
Phorate
Pronamide
Pyrene .
Pyridine
Safrole
Selenium
Silver
Tetrachloro- benzene, 1,2,4,5-
Tetrachloro- ethane, 1,1,1,2-
Tetrachloro- ethane, 1,1,2,2,-
Tetrachloro- ethylene
Tetrachloro- phenol, 2,3,4,6- :
Thallium (I)
Toluene
Trichloro-1 ,2,2,-trifluoroethane, 1 ,1 ,2-
Trichlorobenzene, 1 ,2,4-
Trichloroeth- ane, 1,1,1-
Trichloroeth- ylene
Trichlorofluo- romethane
Trichlorophenol, 2,4,5-
Trichlorophenol, 2;4,6-
Trichlorophenoxyacetic acid, 2,4,5-(245-T)
Triclorophen- oxypropionic acid, 2,4,5- (Silvex)
Trichloropro- pane, 1 ,2,3-
Vanadium
Xylenes (total)
Zinc
WW standard
(mg/l)
15
0 073
390
27
24
39
28
22
0 00044
39
30
n ^
78
7
037
78
8
28
0 66
2
14
•)•)
0 084
3
5
0 081
84
011
21
54
0 16
093
200
023
2
2
30
2200
0 69
48
18
0054
2
1
1
10
22
99
NWW standard
(mg/kg)
420
1 2000
58
27
600000
ocnnnn
1 nnnnn
21000
Qonnn
8
0 56
290
0 18
0 64
0 75
1500
890
1 ?nnnn
1600
on
Qinnnn
280
850
91
250000
38000
1 QOOOO
R
21000
720
•3Rnn
8600
-------
Federal Register / Vol. 60, No. 245 / Thursday, December 21, 1995 / Proposed Rules 66469
§268.71 Associated Management
Requirements.
Waste may meet the standards set out
in the Conditional Minimize Threat
Table as an alternative to the treatment
standards in the tables to Subpart D of
this part or the Minimize Threat Table
to subpart F of this part only if they are
placed in a landfill or a monofill as
defined in 40 CFR 260.10. Waste that is
placed in land application units must
comply with the minimize threat levels
set forth in subpart F of this part or the
treatment standards set forth in subpart
D of this part.
[FR Doc. 95-29458 Filed 12-20-95; 8:45 am]
BILLING CODE 6560-50-P
------- |