Hazardous Waste Management System: Identification and Listing of Hazardous Waste: Conditional Exclusion From Hazardous Waste and Solid Waste for Solvent-Contaminated Industrial Wipes, 55163-55168 [E9-25812]
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Federal Register / Vol. 74, No. 206 / Tuesday, October 27, 2009 / Proposed Rules
public hearing scheduled for
November 4, 2009, is cancelled.
LaNita Van Dyke,
Chief, Publications and Regulations Branch,
Legal Processing Division, Associate Chief
Counsel (Procedure and Administration).
[FR Doc. E9–25743 Filed 10–26–09; 8:45 am]
BILLING CODE 4830–01–P
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 261
[EPA–HQ–RCRA–2003–0004; FRL–8973–2]
RIN 2050–AE51
Hazardous Waste Management
System: Identification and Listing of
Hazardous Waste: Conditional
Exclusion From Hazardous Waste and
Solid Waste for Solvent-Contaminated
Industrial Wipes
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AGENCY: Environmental Protection
Agency.
ACTION: Data availability, management
approaches, and request for comment.
SUMMARY: This notice of data
availability (NODA) invites comments
on a revised risk analysis supporting the
Environmental Protection Agency’s
(EPA) proposed revisions to the
Resource Conservation Recovery Act
(RCRA) hazardous waste regulations
governing the management of solventcontaminated wipes. The revised
analysis addresses public comments
received on the risk screening analysis
conducted on EPA’s 2003 Federal
Register proposal to exclude solventcontaminated wipes from the RCRA
definitions of solid and hazardous
waste. To address these comments, EPA
updated the data, models, and approach
used in the risk analysis and then had
the product peer reviewed by outside
experts. The revised risk analysis, as
well as the peer review comments and
our response to those comments are
available in the docket for this NODA.
The NODA also invites comment on
specific issues in light of the results of
the revised risk analysis.
DATES: Comments must be received
within December 28, 2009.
ADDRESSES: Submit your comments,
identified by Docket ID No. EPA–HQ–
RCRA–2003–0004 by one of the
following methods:
• https://www.regulations.gov: Follow
the on-line instructions for submitting
comments.
• E-mail: rcra-docket@epa.gov,
Attention Docket No. EPA–HQ–RCRA–
2003–0004.
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• Fax: 202–566–9744, Attention
Docket No. EPA–HQ–RCRA–2003–0004.
• Mail: Environmental Protection
Agency, EPA Docket Center (EPA/DC),
Resource Conservation and Recovery
Act (RCRA) Docket, 2822T, 1200
Pennsylvania Avenue, NW.,
Washington, DC 20460, Attention
Docket No. EPA–HQ–RCRA–2003–0004.
Please include 2 copies.
• Hand Delivery: Public Reading
Room, EPA West, Room 3334, 1301
Constitution Ave., NW., Washington,
DC, Attention Docket No. EPA–HQ–
RCRA–2003–0004. Such deliveries are
only accepted during the docket’s
normal hours, and special arrangements
should be made for deliveries of boxed
information.
Instructions: Direct your comments to
Docket ID No. EPA–HQ–RCRA–2003–
0004. EPA’s policy is that all comments
received will be included in the public
docket without change and may be
made available online at https://
www.regulations.gov, including any
personal information provided, unless
the comment includes information
claimed to be Confidential Business
Information (CBI) or other information
whose disclosure is restricted by statute.
Do not send information you consider
CBI or that is otherwise protected
through https://www.regulations.gov or
e-mail. The https://www.regulations.gov
Web site is an ‘‘anonymous access’’
system, which means EPA will not
know your identity or contact
information unless you provide it in the
body of your comment. If you send an
e-mail comment direct to EPA without
going through https://
www.regulations.gov, your e-mail
address will be automatically captured
and included as part of the comment
that is placed in the public docket and
made available on the Internet. If you
send an electronic comment, EPA
recommends that you include your
name and other contact information in
the body of your comment and with any
disk or CD–ROM you send. If EPA
cannot read your comment because of
technical difficulties and cannot contact
you for clarification, EPA may not be
able to consider your comment.
Electronic files should avoid the use of
special characters, any form of
encryption, and be free of any defects or
viruses. For more information about
EPA’s public docket, visit the EPA
Docket Center homepage at https://
www.epa.gov/epahome/dockets.htm.
Docket: All documents in the docket
are listed in the https://
www.regulations.gov index. Although
listed in the index, some information is
not publicly available, e.g., CBI or other
information whose disclosure is
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restricted by statute. Certain other
material, such as copyrighted material,
will be publicly available only in hard
copy. Publicly available docket
materials are available either
electronically in https://
www.regulations.gov or in hard copy at
the Resource Conservation and
Recovery Act (RCRA) Docket, EPA/DC,
EPA West, Room 3334, 1301
Constitution Ave., NW., Washington,
DC. The Public Reading Room is open
from 8:30 a.m. to 4:30 p.m., Monday
through Friday, excluding legal
holidays. The telephone number for the
Public Reading Room is (202) 566–1744,
and the telephone number for the RCRA
Docket is (202) 566–0270.
FOR FURTHER INFORMATION CONTACT:
Teena Wooten, Office of Resource
Conservation and Recovery (ORCR),
(703) 308–8751, wooten.teena@epa.gov.
Direct mail inquiries to the U.S.
Environmental Protection Agency,
Office of Resource Conservation and
Recovery, (Mailstop 5304P), 1200
Pennsylvania Avenue, NW.,
Washington, DC 20460.
SUPPLEMENTARY INFORMATION:
I. General Information
A. Does this Action Apply to Me?
This action may affect up to 164,000
entities in at least 15 industries
involved in the use and handling of
solvent-contaminated wipes. These
industries include, but are not limited
to:
Industry
1. Printing manufacturing.
2. Chemical and allied products manufacturing.
3. Plastics and rubber products manufacturing.
4. Fabricated metal products manufacturing.
5. Industrial machinery and equipment manufacturing.
6. Electronics and computers manufacturing.
7. Transportation equipment manufacturing.
8. Furniture and fixture manufacturing.
9. Auto dealers (retail trade).
10. Publishing (printed matter).
11. Business services.
12. Auto repair and maintenance.
13. Military bases.
14. Solid waste services.
15. Industrial launderers.
This list is not intended to be an
exhaustive list, but rather provides a
guide for readers regarding entities
likely to be covered by this action. This
list includes the types of entities that
EPA is now aware of that could
potentially be covered by this action.
Other types of entities not listed above
could also be addressed by this action.
If you have any questions about the
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applicability of this action to a
particular entity or industry, consult the
individual listed above in the FOR
FURTHER INFORMATION CONTACT Section.
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B. What Should I Consider as I Prepare
My Comments for EPA?
1. Submitting CBI. Do not send CBI
information to EPA through https://
www.regulations.gov or e-mail. Clearly
mark the part or all the information that
you claim to be CBI. For CBI
information on a disk or CD–ROM that
you mail to EPA, mark the disk or CD–
ROM as CBI and then identify
electronically within the disk or CD–
ROM the specific information that is
claimed as CBI. As well as one complete
version of the comment that includes
information claimed as CBI, send a copy
of the comment that does not contain
the information claimed as CBI for
inclusion in the public docket.
Information so marked will not be
disclosed, except under procedures set
forth in 40 CFR part 2.
2. Tips for Preparing Your Comments.
When sending comments, remember to:
• Identify the rulemaking by docket
number and other identifying
information (subject heading, Federal
Register date and page number).
• Follow directions—The agency may
ask you to respond to specific questions
or organize comments by referencing a
Code of Federal Regulations (CFR) part
or section number.
• Explain why you agree or disagree,
suggest alternatives, and substitute
language for your requested changes.
• Describe any assumptions and
provide any technical information or
data that you used.
• If you estimate potential costs or
burdens, explain how you arrived at
your estimate in enough detail to allow
reproduction.
• Provide specific examples to
explain your concerns, and suggest
alternatives.
• Explain your views as clearly as
possible.
• Make sure to send your comments
by the comment period deadline
identified.
The contents of this notice are listed
in the following outline:
I. Background
A. Introduction
B. November 2003 Proposed Rule
Standards and Approach
C. Comments on the 2003 Proposal
II. Methodology and Results of the Revised
Risk Analysis
A. Introduction
B. Were the Documents Peer Reviewed
Before Issuing this Notice?
C. How were the Landfill Loadings for
Solvent-Contaminated Wipes
Determined?
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D. How were the Risk-Based Mass
Loadings Calculated?
E. How were the Risk-Based Mass Loadings
Compared to the Solvent-Quantity
Loadings?
F. What are the Results for the Comparison
of the Loading Estimates?
G. Request for Comment
III. Discussion and Request for Comment on
Management Approaches and Risk
Analysis Findings
IV. Conclusion
I. Background
A. Introduction
A wide variety of industries use wipes
(i.e., rags, shop towels, disposable wipes
and paper towels, collectively called
‘‘wipes’’) for cleaning and degreasing.
The wipes are handled in various ways.
For example, wipes may be used once
or several times before they are thrown
away, while other wipes are used,
laundered, and reused multiple times.
During cleaning and degreasing
operations, these wipes may become
contaminated with solvents, as well as
with other materials (e.g., paints,
varnishes, waxes, metal shavings, inks,
dirt). When discarded, spent wipes are
considered hazardous waste under the
Federal hazardous waste regulations if
the wipes exhibit a hazardous waste
characteristic under 40 CFR part 261,
subpart C or contain a solvent listed in
40 CFR 261.31 (that is, the solvents
included in RCRA waste codes F001
through F005).
Members of the regulated community
petitioned EPA to remove solventcontaminated wipes from the hazardous
waste regulations. The petitioners
argued that when small amounts of
solvent are used on each wipe, minimal
risk occurs from the disposal of such
wipes in municipal solid waste landfills
(MSWLF). Thus, they viewed the
required disposal of the solventcontaminated wipes in RCRA Subtitle C
hazardous waste facilities as
overregulation. Industrial laundries
presented similar arguments and
requested that the solvent-contaminated
wipes they wash before returning them
to their customers for reuse be excluded
from the definition of solid waste. After
a review of the petitions, subsequent
industry requests and information, and
internal EPA analysis, the Agency
decided to propose exclusions from the
RCRA definition of solid waste for
solvent-contaminated wipes sent to a
laundry or dry cleaner and from the
definition of hazardous waste for
solvent-contaminated wipes sent to a
landfill or combustion facility, provided
certain conditions were met. We
published the proposed changes in the
November 20, 2003, Federal Register
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(68 FR 65586). The result of this
proposal, if finalized, would reduce the
regulatory burden on users and handlers
of solvent-contaminated wipes. In
support of the proposed regulatory
change, we completed a risk screening
analysis to evaluate the potential risk at
MSWLFs from the disposal of solventcontaminated wipes and industrial
laundry sludge.
B. November 2003 Proposed Rule
Standards and Approach
To evaluate the appropriate regulatory
status for solvent-contaminated wipes,
we considered the risks to the
environment and public health from the
management of solvent-contaminated
wipes and wastewater treatment sludge
from laundries (laundry sludge) in
MSWLFs. This was done by conducting
a screening analysis to determine the
constituent-specific risks from
landfilling wipes and laundry sludge
contaminated with the F001–F005 listed
(40 CFR 261.31) spent solvents. Then
we estimated the risks from exposure to
the 30 F001–F005 listed solvents
potentially used on wipes, assuming
disposal in an unlined MSWLF.
Specifically, we looked at potential risks
from inhalation of the spent solvents
volatilizing from the landfill, from
ingestion of groundwater contaminated
by the spent solvents leaching from the
landfill, and from inhalation of the
spent solvent vapors released from
contaminated groundwater during
showering and other such uses. Section
V of the Technical Background
Document for the proposed rule [Docket
EPA–HQ–RCRA–2003–0004] provides
details on the risk screening analysis
conducted for the 2003 proposed rule.
C. Comments on the 2003 Proposal
During the comment period on the
proposed rule, we received substantive
comments on the risk screening analysis
and solvent loading calculations from
23 commenters. In addition to public
review and comment, we received
comments from outside peer reviewers.
Both the public and the peer reviewers
questioned the validity of the risk
screening analysis and the modeling
assumptions. These comments are
available in EPA’s Docket No. EPA–HQ–
RCRA–2003–0004.
II. Methodology and Results of the
Revised Risk Analysis
A. Introduction
In response to the comments received
from the peer reviewers and the public
on the risk screening analysis used to
support the proposed rule, we decided
to revisit our risk analysis. Based on this
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review, we determined that a more
robust risk analysis was required to
adequately determine the potential risk
from disposal of solvent-contaminated
wipes and laundry sludge in MSWLFs,
also referred to in this NODA as
landfills or non-hazardous waste
landfills. We have thus completed a
revised risk analysis which is more
robust and more sophisticated than the
original risk screening analysis. The
revised risk analysis includes updated
data and information, a new model to
evaluate the behavior of solvents in a
landfill, revised fate and transport
modeling, including additional
probabilistic modeling, uncertainty and
sensitivity analyses, and an improved
approach to compare the solvent
quantity estimates to the risk-based
solvent levels. Because so much of the
revised risk analysis is new, we believe
it appropriate to make it available for
public comment before making
decisions on the final rule.
The revised risk analysis estimates the
amount of each F-listed solvent that is
present in solvent-contaminated wipes
and laundry sludge disposed of in
MSWLFs. We compared these amounts
to the quantities of spent solvents that
may be disposed of in MSWLFs without
presenting unacceptable risks to human
health and the environment (risk-based
mass loadings). The revised risk
analysis consists of three separate
documents, which are described
generally in this NODA. The documents
are:
—‘‘Landfill Loadings Calculations for
Disposed Solvent-Contaminated
Wipes and Laundry Sludge Managed
in Municipal Landfills’’
—‘‘Risk-Based Mass Loading Limits for
Solvents in Disposed Wipes and
Laundry Sludges Managed in
Municipal Landfills’’
—‘‘F001–F005 Solvent-Contaminated
Wipes and Laundry Sludge:
Comparison of Landfill Loading
Calculations and Risk-Based Mass
Loading Limits’’
For more details about the revised risk
analysis, please see the above
documents in the Docket (EPA–HQ–
RCRA–2003–0004).
The discussion below summarizes our
revised risk analysis for disposal of the
solvent-contaminated wipes and
laundry sludge in landfills.
B. Were the Documents Peer Reviewed
before Issuing this Notice?
The revised risk analysis will be used
to support EPA’s rulemaking to the
RCRA hazardous waste regulations
governing the management of solventcontaminated wipes. Under our peer
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review policy, risk analyses used to
support rulemaking decisions are
influential scientific information.
Therefore, we conducted an external
peer review in accordance with both
EPA’s peer review policy and the Office
of Management and Budget’s (OMB’s)
Final Information Quality Bulletin for
Peer Review. We asked the peer
reviewers to conduct a comprehensive
review of the risk analysis. The peer
reviewers were asked to respond to a set
of questions, which are included in the
public docket for this NODA addressing
the technical basis of the approaches we
used and to prepare a report
highlighting their comments and
recommendations. The peer reviewers
suggested clarifications in several
sections of the ‘‘Landfill Loadings
Calculations for Disposed SolventContaminated Wipes and Laundry
Sludge Managed in Municipal
Landfills’’ document. One reviewer
questioned the method chosen to
determine the uncertainty/variability
distribution, while two reviewers asked
for more information on determining the
number of generators using wipes. The
reviewers also suggested that EPA
review its discussion on sensitivity
analysis. For the ‘‘Risk-Based Mass
Loading Limits for Solvents in Disposed
Wipes and Laundry Sludges Managed in
Municipal Landfills’’ document, the
reviewers recommended more data and
discussion on the model methodology
and results. EPA revised these
documents incorporating the peer
reviewers’ comments, where necessary
and appropriate. The docket contains
the individual peer reviewer reports,
EPA’s response to the peer reviewers’
comments, and supporting documents
for the peer reviews.1 For more
information about the peer review
process, see EPA’s Peer Review
Handbook at https://www.epa.gov/iris/
Peer_Review_Handbook_2006_3rd_
edition.pdf.
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10 eliminated solvents, 5 are ozonedepleting or present other serious
hazards and are therefore banned or
restricted from use. The other 5 solvents
eliminated from the analysis may have
been used on wipes in the past;
however, our research found that these
solvents are currently not used or are
used only in limited quantities in
conjunction with wipes. The Agency
solicits comment on this finding.
After identifying the remaining 20
solvents 3 to evaluate, we used both
deterministic (point-value) and Monte
Carlo (probabilistic) methods in the
analysis. We estimated the number of
generators and the number of wipes
used by those generators. Few
generators have the same solvent use
practices or use the same number of
wipes. To account for these differences,
our revised risk analysis included an
assessment of the uncertainty using
empirical data-based probability
distributions in a Monte Carlo analysis.
We conducted a separate sensitivity
analysis to assess the influence that
each input parameter has on the result.
These results identify the most and least
influential assumptions. We estimated
the amount of solvent that could be on
a wipe or in laundry sludge before
disposal and then estimated the number
of generators potentially disposing of
solvent-contaminated wipes or laundry
sludge into a single MSWLF. Through
our calculations, we derived estimated
landfill loadings for the solvents. The
full report, ‘‘Landfill Loadings
Calculations For Disposed SolventContaminated Wipes and Laundry
Sludge Managed in Municipal
Landfills’’ describes the assumptions
made, methodologies used, and the
results of the analysis. The Docket
(EPA–HQ–RCRA–2003–0004) for this
NODA contains this document.
C. How were the Landfill Loadings for
Solvent-Contaminated Wipes
Determined?
We began the evaluation by looking at
the 30 solvents listed in 40 CFR 261.31
(F001–F005). Through literature review
and site visits, we eliminated 10 of these
30 solvents 2 from the analysis. Of the
D. How were the Risk-Based Mass
Loadings Calculated?
We also developed a methodology to
estimate the amount of hazardous spent
solvents that could be disposed of in
MSWLFs (unlined and composite
lined), and be protective of human
health and the environment at the point
of exposure. These ‘‘allowable amounts’’
are risk-based mass loading rates
expressed in kg of each spent solvent
1 The ‘‘F001–F005 Solvent-Contaminated Wipes
and Laundry Sludge: Comparison of Landfill
Loading Calculations and Risk-Based Mass Loading
Limits’’ document was developed after completion
of the peer reviews.
2 Carbon tetrachloride, 1,1,1-Trichloroethane,
Trichlorofluoromethane, Dichlorodifluoromethane,
1,1,2-Trichlorotrifluorethane (ozone depleting
substances), Carbon disulfide, ethyl ether,
Nitrobenzene, 2-Nirtopropane, Pyridine (not know
to be used as solvents in wipes applications). For
the discussion on the solvents, see the ‘‘Landfill
Loadings Calculations for Disposed SolventContaminated Wipes and Laundry Sludge Managed
in Municipal Landfills’’ Section 1.2.1 and 1.2.2.
3 Acetone, benzene, butanol, chlorobenzene,
cresols (total), cyclohexanone, dichlorobenzene, 1,
2-ethoxyethanol, 2-ethyl acetate, ethyl benzene,
isobutanol, methanol, methyl ethyl ketone, methyl
isobutyl ketone, methylene chloride,
tetrachloroethylene, toluene, trichloroethane, 1,1,2trichloroethylene, xylene (mixed isomers).
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that can be added to a landfill in a given
year. These risk-based mass loading
rates were derived from modeling
scenarios defined in terms of the
solvent, landfill type (e.g., lined or
unlined), exposure pathway (e.g.,
ambient air inhalation), contact media
(e.g., groundwater), and receptor (e.g.,
child or adult). Mass loading rates were
estimated for each solvent such that the
exposure at the 50th and 90th
percentiles of the risk distribution
would not exceed the identified risk
target criteria, if these materials were
disposed of in a MSWLF. The 50th and
90th percentiles are typically used by
the Agency to characterize risk. The
90th percentile represents a ‘‘high end’’
estimate of individual risk, while the
50th percentile results reflect the central
tendency estimate of the risk
distribution.4 For this analysis, the risk
criteria were selected so that either 50
or 90 percent of the hypothetical
individuals living near a landfill will
not be exposed to solvent releases
resulting in an excess lifetime cancer
risk above 1 chance in 10,000 (10¥4)
through 1 chance in 1,000,000 (10¥6).5
For noncancer health effects, we used a
hazard quotient (HQ) of one as our risk
criterion (the noncancer HQ is defined
as the ratio of predicted intake levels to
safe intake levels).
We identified the following exposure
pathways based on the solubility and
volatility of the 20 spent solvents
included in the analysis, as well as the
operating practices of nonhazardous
waste landfills:
(1) Inhalation of ambient air
containing spent solvents emitted from
the landfill at residential dwellings;
(2) Ingestion of spent solvents that
leach from the landfill and migrate
through groundwater to residential
drinking water wells;
(3) Inhalation of spent solvents during
showering and bathing with solventcontaminated groundwater; and
(4) Dermal contact of spent solvents
during showering and bathing with
solvent-contaminated groundwater.
A probabilistic approach was used to
develop national mass loading rates
because landfills that receive solventcontaminated wipes and laundry sludge
could be of varying geometry and
located in many different parts of the
4 Guidance
for Risk Characterization, U.S.
Environmental Protection Agency, 1995.
5 These risk criteria are consistent with those
discussed in EPA’s hazardous waste listing
determination policy (see December 22, 1994; 59 FR
66072). Also see 40 CFR 300.430(e)(2)(i)(A)(2),
which establishes a cancer risk range of 10¥4 to
10¥6 in the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP) for responding to
releases of hazardous substances under Superfund.
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country. The approach primarily
addresses the variability in waste
management practices (that is, unlined
and composite lined landfills),
environmental settings, and exposurerelated parameters. We also developed a
landfill source model to simulate the
solvent-specific air emissions and
leachate releases from landfills. The
quantity of solvent releases to the air
and groundwater were then used as
inputs to the air and groundwater fate
and transport models.
For each solvent, we calculated risk
estimates assuming a unitized mass
loading rate (1 kg per year) for each liner
type, exposure pathway, and receptor,
as well as for the combined exposures
associated with groundwater uses. The
risk results provide insight into the
relative nature of exposures and
potential risks that could be associated
with the solvent-contaminated wipes
disposed of in MSWLFs.
For unlined landfills, the groundwater
pathways were always associated with
the highest predicted risks at the 50th
and 90th percentiles of the
distributions. For composite lined
landfills, groundwater exposures were
associated with the highest risks at the
90th percentile, except for methylene
chloride and methyl ethyl ketone,
which showed higher risks for the
ambient air inhalation pathway. At the
50th percentile, the highest predicted
risks were associated with the ambient
air inhalation pathway for 16 of the 20
solvents; however, for unlined landfill
disposal, the predicted risks were
associated more with drinking water.
From this information, we developed
solvent-specific risk-based mass loading
rates (in kg/yr) that could be disposed
of in a MSWLF and meet specific risk
criteria and be protective of human
health and the environment. The riskbased mass loading rates do not provide
direct insight into the potential impacts
associated with current management
practices. The full report, ‘‘Risk-Based
Mass Loading Limits for Solvents in
Disposed Wipes and Laundry Sludges
Managed in Municipal Landfills’’
describes the assumptions made,
methodologies used, and the results of
the analysis. The Docket for this NODA
(EPA–HQ–RCRA–2003–0004) contains
this document.
E. How were the Risk-Based Mass
Loadings Compared to the SolventQuantity Loadings?
To perform a comparison, EPA
evaluated a 90th percentile risk criterion
for the risk-based mass loading limit to
be protective of 90 percent of
hypothetically exposed individuals
across all of the landfill sites in the
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United States (Guidance for Risk
Characterization, U.S. Environmental
Protection Agency, 1995; accessible at
https://www.epa.gov/OSA/spc/pdfs/
rcguide.pdf, which states that ‘‘For the
Agency’s purposes, high end risk
descriptors are plausible estimates of
the individual risk for those persons at
the upper end of the risk distribution,’’
or conceptually, individuals with
‘‘exposure above about the 90th
percentile of the population
distribution’’). As recommended in the
Guidance, EPA also evaluated the 50th
percentile results as the central
tendency estimate of that risk
distribution. Thus, we compared the
90th percentile estimate of landfill
loading rates (ELLRs) to the 90th
percentile of the risk-based mass
loading levels (RB–MLLs) to determine
whether the ELLRs in landfills that can
be attributed to solvent-contaminated
wipes and laundry sludge exceeds the
RB–MLLs that correspond to selected
health-based limits. A similar
comparison was conducted at the 50th
percentile.
F. What are the Results for the
Comparison of the Loading Estimates?
The results for both the ELLR and the
RB–MLL are generated from a
probabilistic analysis. The results from
these two separate calculations are
given by a distribution of values. The
theoretical risk distribution provides the
basis for calculating risk-based mass
loading rates for any percentile of that
distribution. Based on the risk criteria
that EPA evaluated for the wipes
analysis, the RB–MLL was identified at
the 50th and 90th percentiles of the
distribution. These levels represent the
allowable mass loading rate (in kg per
year) for management of solventcontaining wipes and laundry sludges
in a MSWLFs anywhere in the country
in any given year.
The comparisons of the ELLRs and
RB–MLLs are expressed as ratios, i.e.,
the 90th percentile ELLRs (kg solvent
per year) are divided by the 90th
percentile RB–MLLs (kg solvent per
year) for a specific solvent to yield
ratios. The ELLR is an estimate of the
mass loading into the landfill and the
RB–MLL is an estimate of the mass
loading that would correspond to an
exposure equivalent to the chosen risk
criterion, or risk ‘‘target.’’ Therefore, if
the ratio exceeds one, this indicates the
degree to which the ELLR exceeds the
evaluation criteria used to establish the
RB–MLLs (i.e., a cancer risk of 1 × 10¥5
and an HQ of 1 for noncarcinogenic
risk).
The comparison of the 90th percentile
values of the ELLRs and the RB–MLLs
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indicates that 8 of the 20 spent solvents
could pose potential risks above EPA’s
evaluated criteria at some risk levels for
unlined landfills. The 90th percentile
risks for benzene (using the high end
cancer risk value only), 1,1,2trichloroethane, methylene chloride,
tetrachloroethylene, and
trichloroethylene exceeded the 10¥5
cancer risk criteria. The 90th percentile
risks for chlorobenzene, toluene, and
xylenes exceeded the criteria for noncancer health effects (HQ = 1). As
expected, the predicted risks for the
unlined landfill analysis were always
greater than those for the compositelined landfill analysis. Using the
comparison of the 90th percentile
results, the potential risks from all
solvents examined in the compositeliner scenario, except for
tetrachloroethylene, were well below
(generally <0.1) the health-based criteria
used in this analysis. The value for
tetrachloroethylene was 1.1 using the
higher end cancer risk value and 0.9
using the lower end cancer risk value.
For a more detailed explanation of how
the ELLR and RB–MLL were compared,
see the ‘‘F001–F005 SolventContaminated Wipes and Laundry
Sludge: Comparison of Landfill Loading
Calculations and Risk Based Mass
Loading Limits’’ document in the docket
for this NODA.
A comparison of the ELLR and RB–
MLL central tendency values (50th
percentiles), showed that
tetrachloroethylene is the only solvent
in the unlined landfill scenario that
produced a ratio of ELLR to RB–MLL
greater than one (using a cancer risk of
1 × 10¥5 and an HQ of 1) and this value
was 1.4 using the higher end cancer risk
value; using the lower end cancer risk
value, the ratio was 1.2. For the
composite liner scenario, all ratios of
the 50th percentile ELLRs and RB–MLLs
are well below one using these risk
criteria.
The ratios from a comparison of the
ELLRs and the RB–MLLs for the
constituents with carcinogenic risk
would change if the RB–MLLs were
calculated using a risk criterion
different from the 1 × 10¥5 criterion. If
a target risk level of 1 × 10¥4 were used
for calculating the RB–MLLs, the
carcinogenic risk for the carcinogens
(1,1,2-trichloroethane, benzene,
methylene chloride,
tetrachloroethylene, and
trichloroethylene) would be lower by a
factor of ten. Alternatively, if a target
risk level of 1 × 10¥6 were used, the
cancer risks for these constituents
would be higher by a factor of ten. A
comparison of the ELLR and RB–MLL
values using the 10¥4 risk criterion for
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16:44 Oct 26, 2009
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the no-liner scenario would have the
effect of lowering the ratios; however,
the ratios of 7 of the 8 solvents of
potential concern would remain above
one at the 90th percentile (the ratio for
benzene would be less than one). Using
the 10¥4 criterion at the 50th percentile,
the ratios for all the solvents would be
below one. Using the 10¥6 risk criterion
would have the effect of raising the
ratios in the unlined landfill scenario
for carcinogens, such that the ratios for
all these 8 solvents for the 90th
percentile results would exceed one by
a wider margin. Using the 10¥6 risk
criterion, the ratios from the 50th
percentile results would increase for the
carcinogenic solvents, such that the
ratios for tetrachloroethylene and
trichloroethylene would exceed one at
the 50th percentiles.
For the composite-liner scenario, the
ratios for all solvents would be below
one (including tetrachloroethylene) at
both the 90th and 50th percentiles using
the 10¥4 risk criterion. Using the 10¥6
criterion, the ratios for
tetrachloroethylene and
trichloroethylene at the 90th percentile
are above one.
These results differ from our original
risk screening analysis for the proposed
rule in the following ways:
• The number of solvents that show
a potential risk for disposal in an
unlined landfill in our risk screening
analysis increased by 2 in the revised
analysis and the solvents indicating a
potential risk also changed.6
• In the original risk screening
analysis, we did not consider risks from
lined landfills. The revised risk analysis
does consider risks from composite
lined non-hazardous waste landfills.
• In the original risk screening
analysis, we did not identify any
solvents of concern from laundry
sludge. Our revised risk analysis
indicates that tetrachloroethylene may
be a concern in both solventcontaminated wipes and laundry sludge
disposed of in unlined and composite
lined landfills.
G. Request for Comment
We are seeking comment on all
aspects of the revised risk analysis
(landfill loading calculations, risk based
mass loading levels, comparison
document). In particular, we are seeking
comment on:
6 Solvents in the proposal indicating a potential
risk in unlined landfill scenario: Methyl ethyl
ketone, methyl isobutyl ketone, nitrobenzene,
pyridine, methylene chloride, 2-nitroproane.
Solvents from revised risk analysis indicating a
potential risk in unlined landfill scenario: benzene,
1,1,2-trichloroethane, chlorobenzene, methylene
chloride, tetrachloroethylene, toluene,
trichloroethylene, and xylene.
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55167
—The assumptions used;
—Whether the uncertainties are
properly acknowledged and mitigated,
as appropriate;
—The data used;
—The methodology used; and
—How the agency should consider
using the results of the revised risk
analysis in its decision-making.
III. Discussion and Request for
Comment on Management Approaches
and Risk Analysis Findings
The Agency’s November 2003
proposal allowed solvent-contaminated
wipes and laundry sludge that met
certain conditions to be sent either to a
MSWLF or to another nonhazardous
waste landfill that meets the standards
under 40 CFR part 257, subpart B. We
did not discuss the specific
characteristics of MSWLFs receiving
solvent-contaminated wipes or laundry
sludge, specifically whether the landfill
would be unlined or lined. Because our
revised risk analysis indicates that a
number of solvents show a potential for
risk in unlined landfills (using the 90th
percentile results and a risk criterion of
1 × 10¥5 for cancer risk), we are
considering two additional approaches
for managing solvent-contaminated
wipes and laundry sludge in landfills.
The first approach would allow the
disposal of solvents not showing a risk
in any municipal landfill or
nonhazardous waste landfill whether
lined or unlined. The solvents that
indicated a potential risk if disposed of
in an unlined landfill 7 could only be
disposed in a lined municipal landfill or
lined non-hazardous waste landfill. This
could be accomplished by requiring
disposal in a Subtitle D municipal or
industrial landfill unit subject to, or
otherwise meeting, the landfill
requirements in 40 CFR 258.40(a)(2) and
(b).8 9 The second approach would be to
7 Benzene, 1,1,2-trichloroethane, chlorobenzene,
methylene chloride, toluene, trichloroethylene, and
xylene.
8 40 CFR 258.40(a)(2) states: ‘‘With a composite
liner, as defined in paragraph (b) of this section and
a leachate collection system that is designed and
constructed to maintain less than a 30-cm depth of
leachate over the liner. 40 CFR 258.40(b) states ‘‘For
purposes of this section, composite liner means a
system consisting of two components; the upper
component must consist of a minimum 30-mil
flexible membrane liner (FML), and the lower
component must consist of at least a two-foot layer
of compacted soil with a hydraulic conductivity of
no more than 1 × 10¥7cm/sec. FML components
consisting of high density polyethylene (HDPE)
shall be at least 60-mil thick. The FML component
must be installed in direct and uniform contact
with the compacted soil component.’’
9 Solvent-contaminated wipes, while not
required, could also be disposed of in a hazardous
waste landfill meeting the landfill requirements in
40 CFR 264.301 or 265.301.
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establish conditions that allow all
solvent-contaminated wipes, no matter
which solvent they contain, except
perhaps tetrachloroethylene, to be sent
to a Subtitle D municipal or industrial
landfill unit subject to, or otherwise
meeting, the landfill requirements in
§ 258.40(a)(2) and (b). This approach
could be simpler since the generator
would not need to separate his wipes
and send them to separate disposal
locations. We are requesting comment
on these two approaches.
The risk analysis using 90th
percentile results also indicates that
tetrachloroethylene has a risk potential
in both unlined landfills and composite
lined landfills for both solventcontaminated wipes and laundry sludge
(using a cancer risk criterion of 1 ×
10¥5). Using the higher end cancer risk
value in our analysis, the ratio of the
ELLR to the RB–MLL for
tetrachloroethylene was 1.1, while using
the lower end cancer risk value the ratio
was 0.9. If we rounded the numbers, the
ratios would both be 1.0. Since we
generally used a conservative approach
in the risk analysis, we are asking for
comment on whether our results
represent a risk of concern.
Even though the risk may be
borderline, we are considering
alternative management conditions for
tetrachloroethylene to address this
potential risk. One approach is to
prohibit disposal of tetrachloroethylene,
either on solvent-contaminated wipes or
in laundry sludge that exhibits the
tetrachloroethylene toxicity
characteristic (TC) in nonhazardous
waste landfills. Another approach could
be eliminating wipes contaminated with
tetrachloroethylene from the scope of
the final exclusions for solventcontaminated wipes, or eliminating
wipes contaminated with
tetrachloroethylene that exhibit the TC
in the scope of the final exclusions for
solvent-contaminated wipes. We are
requesting comment on these
approaches or other possible
alternatives.
IV. Conclusion
We will consider comments received
on the revised risk analysis and then
modify the analysis as appropriate. The
final risk analysis, comments submitted
in response to Section III of this notice,
and comments submitted in response to
the November 2003 proposed rule will
be considered as we develop a final rule
for the management of solventcontaminated wipes.
Readers should note that other than
the specific issues identified in this
NODA, no other issues discussed in or
related to the November 20, 2003,
VerDate Nov<24>2008
16:44 Oct 26, 2009
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proposed rule are open for further
comment and the Agency will not
respond to any comments received on
any issues not identified in this NODA.
Dated: October 15, 2009.
Mathy Stanislaus,
Assistant Administrator, Office of Solid Waste
and Emergency Response.
[FR Doc. E9–25812 Filed 10–26–09; 8:45 am]
BILLING CODE 6560–50–P
Washington, DC 20472, (202) 646–2820,
or (e-mail) kevin.long@dhs.gov.
FOR FURTHER INFORMATION CONTACT:
Kevin C. Long, Acting Chief,
Engineering Management Branch,
Mitigation Directorate, Federal
Emergency Management Agency, 500 C
Street, SW., Washington, DC 20472,
(202) 646–2820, or (e-mail)
kevin.long@dhs.gov.
The
Federal Emergency Management Agency
(FEMA) proposes to make
determinations of BFEs and modified
BFEs for each community listed below,
in accordance with section 110 of the
Flood Disaster Protection Act of 1973,
42 U.S.C. 4104, and 44 CFR 67.4(a).
These proposed BFEs and modified
BFEs, together with the floodplain
management criteria required by 44 CFR
60.3, are the minimum that are required.
They should not be construed to mean
that the community must change any
existing ordinances that are more
stringent in their floodplain
management requirements. The
community may at any time enact
stricter requirements of its own, or
pursuant to policies established by other
Federal, State, or regional entities.
These proposed elevations are used to
meet the floodplain management
requirements of the NFIP and are also
used to calculate the appropriate flood
insurance premium rates for new
buildings built after these elevations are
made final, and for the contents in these
buildings.
Comments on any aspect of the Flood
Insurance Study and FIRM, other than
the proposed BFEs, will be considered.
A letter acknowledging receipt of any
comments will not be sent.
National Environmental Policy Act.
This proposed rule is categorically
excluded from the requirements of 44
CFR part 10, Environmental
Consideration. An environmental
impact assessment has not been
prepared.
Regulatory Flexibility Act. As flood
elevation determinations are not within
the scope of the Regulatory Flexibility
Act, 5 U.S.C. 601–612, a regulatory
flexibility analysis is not required.
Executive Order 12866, Regulatory
Planning and Review. This proposed
rule is not a significant regulatory action
under the criteria of section 3(f) of
Executive Order 12866, as amended.
Executive Order 13132, Federalism.
This proposed rule involves no policies
that have federalism implications under
Executive Order 13132.
Executive Order 12988, Civil Justice
Reform. This proposed rule meets the
SUPPLEMENTARY INFORMATION:
DEPARTMENT OF HOMELAND
SECURITY
Federal Emergency Management
Agency
44 CFR Part 67
[Docket ID FEMA–2008–0020; Internal
Agency Docket No. FEMA–B–1075]
Proposed Flood Elevation
Determinations
AGENCY: Federal Emergency
Management Agency, DHS.
ACTION: Proposed rule.
SUMMARY: Comments are requested on
the proposed Base (1% annual-chance)
Flood Elevations (BFEs) and proposed
BFE modifications for the communities
listed in the table below. The purpose
of this notice is to seek general
information and comment regarding the
proposed regulatory flood elevations for
the reach described by the downstream
and upstream locations in the table
below. The BFEs and modified BFEs are
a part of the floodplain management
measures that the community is
required either to adopt or show
evidence of having in effect in order to
qualify or remain qualified for
participation in the National Flood
Insurance Program (NFIP). In addition,
these elevations, once finalized, will be
used by insurance agents, and others to
calculate appropriate flood insurance
premium rates for new buildings and
the contents in those buildings.
DATES: Comments are to be submitted
on or before January 25, 2010.
ADDRESSES: The corresponding
preliminary Flood Insurance Rate Map
(FIRM) for the proposed BFEs for each
community is available for inspection at
the community’s map repository. The
respective addresses are listed in the
table below.
You may submit comments, identified
by Docket No. FEMA–B–1075, to Kevin
C. Long, Acting Chief, Engineering
Management Branch, Mitigation
Directorate, Federal Emergency
Management Agency, 500 C Street, SW.,
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Agencies
[Federal Register Volume 74, Number 206 (Tuesday, October 27, 2009)]
[Proposed Rules]
[Pages 55163-55168]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-25812]
=======================================================================
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 261
[EPA-HQ-RCRA-2003-0004; FRL-8973-2]
RIN 2050-AE51
Hazardous Waste Management System: Identification and Listing of
Hazardous Waste: Conditional Exclusion From Hazardous Waste and Solid
Waste for Solvent-Contaminated Industrial Wipes
AGENCY: Environmental Protection Agency.
ACTION: Data availability, management approaches, and request for
comment.
-----------------------------------------------------------------------
SUMMARY: This notice of data availability (NODA) invites comments on a
revised risk analysis supporting the Environmental Protection Agency's
(EPA) proposed revisions to the Resource Conservation Recovery Act
(RCRA) hazardous waste regulations governing the management of solvent-
contaminated wipes. The revised analysis addresses public comments
received on the risk screening analysis conducted on EPA's 2003 Federal
Register proposal to exclude solvent-contaminated wipes from the RCRA
definitions of solid and hazardous waste. To address these comments,
EPA updated the data, models, and approach used in the risk analysis
and then had the product peer reviewed by outside experts. The revised
risk analysis, as well as the peer review comments and our response to
those comments are available in the docket for this NODA. The NODA also
invites comment on specific issues in light of the results of the
revised risk analysis.
DATES: Comments must be received within December 28, 2009.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
RCRA-2003-0004 by one of the following methods:
https://www.regulations.gov: Follow the on-line
instructions for submitting comments.
E-mail: rcra-docket@epa.gov, Attention Docket No. EPA-HQ-
RCRA-2003-0004.
Fax: 202-566-9744, Attention Docket No. EPA-HQ-RCRA-2003-
0004.
Mail: Environmental Protection Agency, EPA Docket Center
(EPA/DC), Resource Conservation and Recovery Act (RCRA) Docket, 2822T,
1200 Pennsylvania Avenue, NW., Washington, DC 20460, Attention Docket
No. EPA-HQ-RCRA-2003-0004. Please include 2 copies.
Hand Delivery: Public Reading Room, EPA West, Room 3334,
1301 Constitution Ave., NW., Washington, DC, Attention Docket No. EPA-
HQ-RCRA-2003-0004. Such deliveries are only accepted during the
docket's normal hours, and special arrangements should be made for
deliveries of boxed information.
Instructions: Direct your comments to Docket ID No. EPA-HQ-RCRA-
2003-0004. EPA's policy is that all comments received will be included
in the public docket without change and may be made available online at
https://www.regulations.gov, including any personal information
provided, unless the comment includes information claimed to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Do not send information you
consider CBI or that is otherwise protected through https://www.regulations.gov or e-mail. The https://www.regulations.gov Web site
is an ``anonymous access'' system, which means EPA will not know your
identity or contact information unless you provide it in the body of
your comment. If you send an e-mail comment direct to EPA without going
through https://www.regulations.gov, your e-mail address will be
automatically captured and included as part of the comment that is
placed in the public docket and made available on the Internet. If you
send an electronic comment, EPA recommends that you include your name
and other contact information in the body of your comment and with any
disk or CD-ROM you send. If EPA cannot read your comment because of
technical difficulties and cannot contact you for clarification, EPA
may not be able to consider your comment. Electronic files should avoid
the use of special characters, any form of encryption, and be free of
any defects or viruses. For more information about EPA's public docket,
visit the EPA Docket Center homepage at https://www.epa.gov/epahome/dockets.htm.
Docket: All documents in the docket are listed in the https://www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available either electronically
in https://www.regulations.gov or in hard copy at the Resource
Conservation and Recovery Act (RCRA) Docket, EPA/DC, EPA West, Room
3334, 1301 Constitution Ave., NW., Washington, DC. The Public Reading
Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday,
excluding legal holidays. The telephone number for the Public Reading
Room is (202) 566-1744, and the telephone number for the RCRA Docket is
(202) 566-0270.
FOR FURTHER INFORMATION CONTACT: Teena Wooten, Office of Resource
Conservation and Recovery (ORCR), (703) 308-8751, wooten.teena@epa.gov.
Direct mail inquiries to the U.S. Environmental Protection Agency,
Office of Resource Conservation and Recovery, (Mailstop 5304P), 1200
Pennsylvania Avenue, NW., Washington, DC 20460.
SUPPLEMENTARY INFORMATION:
I. General Information
A. Does this Action Apply to Me?
This action may affect up to 164,000 entities in at least 15
industries involved in the use and handling of solvent-contaminated
wipes. These industries include, but are not limited to:
------------------------------------------------------------------------
Industry
-------------------------------------------------------------------------
1. Printing manufacturing.
2. Chemical and allied products manufacturing.
3. Plastics and rubber products manufacturing.
4. Fabricated metal products manufacturing.
5. Industrial machinery and equipment manufacturing.
6. Electronics and computers manufacturing.
7. Transportation equipment manufacturing.
8. Furniture and fixture manufacturing.
9. Auto dealers (retail trade).
10. Publishing (printed matter).
11. Business services.
12. Auto repair and maintenance.
13. Military bases.
14. Solid waste services.
15. Industrial launderers.
------------------------------------------------------------------------
This list is not intended to be an exhaustive list, but rather
provides a guide for readers regarding entities likely to be covered by
this action. This list includes the types of entities that EPA is now
aware of that could potentially be covered by this action. Other types
of entities not listed above could also be addressed by this action. If
you have any questions about the
[[Page 55164]]
applicability of this action to a particular entity or industry,
consult the individual listed above in the FOR FURTHER INFORMATION
CONTACT Section.
B. What Should I Consider as I Prepare My Comments for EPA?
1. Submitting CBI. Do not send CBI information to EPA through
https://www.regulations.gov or e-mail. Clearly mark the part or all the
information that you claim to be CBI. For CBI information on a disk or
CD-ROM that you mail to EPA, mark the disk or CD-ROM as CBI and then
identify electronically within the disk or CD-ROM the specific
information that is claimed as CBI. As well as one complete version of
the comment that includes information claimed as CBI, send a copy of
the comment that does not contain the information claimed as CBI for
inclusion in the public docket. Information so marked will not be
disclosed, except under procedures set forth in 40 CFR part 2.
2. Tips for Preparing Your Comments. When sending comments,
remember to:
Identify the rulemaking by docket number and other
identifying information (subject heading, Federal Register date and
page number).
Follow directions--The agency may ask you to respond to
specific questions or organize comments by referencing a Code of
Federal Regulations (CFR) part or section number.
Explain why you agree or disagree, suggest alternatives,
and substitute language for your requested changes.
Describe any assumptions and provide any technical
information or data that you used.
If you estimate potential costs or burdens, explain how
you arrived at your estimate in enough detail to allow reproduction.
Provide specific examples to explain your concerns, and
suggest alternatives.
Explain your views as clearly as possible.
Make sure to send your comments by the comment period
deadline identified.
The contents of this notice are listed in the following outline:
I. Background
A. Introduction
B. November 2003 Proposed Rule Standards and Approach
C. Comments on the 2003 Proposal
II. Methodology and Results of the Revised Risk Analysis
A. Introduction
B. Were the Documents Peer Reviewed Before Issuing this Notice?
C. How were the Landfill Loadings for Solvent-Contaminated Wipes
Determined?
D. How were the Risk-Based Mass Loadings Calculated?
E. How were the Risk-Based Mass Loadings Compared to the
Solvent-Quantity Loadings?
F. What are the Results for the Comparison of the Loading
Estimates?
G. Request for Comment
III. Discussion and Request for Comment on Management Approaches and
Risk Analysis Findings
IV. Conclusion
I. Background
A. Introduction
A wide variety of industries use wipes (i.e., rags, shop towels,
disposable wipes and paper towels, collectively called ``wipes'') for
cleaning and degreasing. The wipes are handled in various ways. For
example, wipes may be used once or several times before they are thrown
away, while other wipes are used, laundered, and reused multiple times.
During cleaning and degreasing operations, these wipes may become
contaminated with solvents, as well as with other materials (e.g.,
paints, varnishes, waxes, metal shavings, inks, dirt). When discarded,
spent wipes are considered hazardous waste under the Federal hazardous
waste regulations if the wipes exhibit a hazardous waste characteristic
under 40 CFR part 261, subpart C or contain a solvent listed in 40 CFR
261.31 (that is, the solvents included in RCRA waste codes F001 through
F005).
Members of the regulated community petitioned EPA to remove
solvent-contaminated wipes from the hazardous waste regulations. The
petitioners argued that when small amounts of solvent are used on each
wipe, minimal risk occurs from the disposal of such wipes in municipal
solid waste landfills (MSWLF). Thus, they viewed the required disposal
of the solvent-contaminated wipes in RCRA Subtitle C hazardous waste
facilities as overregulation. Industrial laundries presented similar
arguments and requested that the solvent-contaminated wipes they wash
before returning them to their customers for reuse be excluded from the
definition of solid waste. After a review of the petitions, subsequent
industry requests and information, and internal EPA analysis, the
Agency decided to propose exclusions from the RCRA definition of solid
waste for solvent-contaminated wipes sent to a laundry or dry cleaner
and from the definition of hazardous waste for solvent-contaminated
wipes sent to a landfill or combustion facility, provided certain
conditions were met. We published the proposed changes in the November
20, 2003, Federal Register (68 FR 65586). The result of this proposal,
if finalized, would reduce the regulatory burden on users and handlers
of solvent-contaminated wipes. In support of the proposed regulatory
change, we completed a risk screening analysis to evaluate the
potential risk at MSWLFs from the disposal of solvent-contaminated
wipes and industrial laundry sludge.
B. November 2003 Proposed Rule Standards and Approach
To evaluate the appropriate regulatory status for solvent-
contaminated wipes, we considered the risks to the environment and
public health from the management of solvent-contaminated wipes and
wastewater treatment sludge from laundries (laundry sludge) in MSWLFs.
This was done by conducting a screening analysis to determine the
constituent-specific risks from landfilling wipes and laundry sludge
contaminated with the F001-F005 listed (40 CFR 261.31) spent solvents.
Then we estimated the risks from exposure to the 30 F001-F005 listed
solvents potentially used on wipes, assuming disposal in an unlined
MSWLF. Specifically, we looked at potential risks from inhalation of
the spent solvents volatilizing from the landfill, from ingestion of
groundwater contaminated by the spent solvents leaching from the
landfill, and from inhalation of the spent solvent vapors released from
contaminated groundwater during showering and other such uses. Section
V of the Technical Background Document for the proposed rule [Docket
EPA-HQ-RCRA-2003-0004] provides details on the risk screening analysis
conducted for the 2003 proposed rule.
C. Comments on the 2003 Proposal
During the comment period on the proposed rule, we received
substantive comments on the risk screening analysis and solvent loading
calculations from 23 commenters. In addition to public review and
comment, we received comments from outside peer reviewers. Both the
public and the peer reviewers questioned the validity of the risk
screening analysis and the modeling assumptions. These comments are
available in EPA's Docket No. EPA-HQ-RCRA-2003-0004.
II. Methodology and Results of the Revised Risk Analysis
A. Introduction
In response to the comments received from the peer reviewers and
the public on the risk screening analysis used to support the proposed
rule, we decided to revisit our risk analysis. Based on this
[[Page 55165]]
review, we determined that a more robust risk analysis was required to
adequately determine the potential risk from disposal of solvent-
contaminated wipes and laundry sludge in MSWLFs, also referred to in
this NODA as landfills or non-hazardous waste landfills. We have thus
completed a revised risk analysis which is more robust and more
sophisticated than the original risk screening analysis. The revised
risk analysis includes updated data and information, a new model to
evaluate the behavior of solvents in a landfill, revised fate and
transport modeling, including additional probabilistic modeling,
uncertainty and sensitivity analyses, and an improved approach to
compare the solvent quantity estimates to the risk-based solvent
levels. Because so much of the revised risk analysis is new, we believe
it appropriate to make it available for public comment before making
decisions on the final rule.
The revised risk analysis estimates the amount of each F-listed
solvent that is present in solvent-contaminated wipes and laundry
sludge disposed of in MSWLFs. We compared these amounts to the
quantities of spent solvents that may be disposed of in MSWLFs without
presenting unacceptable risks to human health and the environment
(risk-based mass loadings). The revised risk analysis consists of three
separate documents, which are described generally in this NODA. The
documents are:
--``Landfill Loadings Calculations for Disposed Solvent-Contaminated
Wipes and Laundry Sludge Managed in Municipal Landfills''
--``Risk-Based Mass Loading Limits for Solvents in Disposed Wipes and
Laundry Sludges Managed in Municipal Landfills''
--``F001-F005 Solvent-Contaminated Wipes and Laundry Sludge: Comparison
of Landfill Loading Calculations and Risk-Based Mass Loading Limits''
For more details about the revised risk analysis, please see the above
documents in the Docket (EPA-HQ-RCRA-2003-0004).
The discussion below summarizes our revised risk analysis for
disposal of the solvent-contaminated wipes and laundry sludge in
landfills.
B. Were the Documents Peer Reviewed before Issuing this Notice?
The revised risk analysis will be used to support EPA's rulemaking
to the RCRA hazardous waste regulations governing the management of
solvent-contaminated wipes. Under our peer review policy, risk analyses
used to support rulemaking decisions are influential scientific
information. Therefore, we conducted an external peer review in
accordance with both EPA's peer review policy and the Office of
Management and Budget's (OMB's) Final Information Quality Bulletin for
Peer Review. We asked the peer reviewers to conduct a comprehensive
review of the risk analysis. The peer reviewers were asked to respond
to a set of questions, which are included in the public docket for this
NODA addressing the technical basis of the approaches we used and to
prepare a report highlighting their comments and recommendations. The
peer reviewers suggested clarifications in several sections of the
``Landfill Loadings Calculations for Disposed Solvent-Contaminated
Wipes and Laundry Sludge Managed in Municipal Landfills'' document. One
reviewer questioned the method chosen to determine the uncertainty/
variability distribution, while two reviewers asked for more
information on determining the number of generators using wipes. The
reviewers also suggested that EPA review its discussion on sensitivity
analysis. For the ``Risk-Based Mass Loading Limits for Solvents in
Disposed Wipes and Laundry Sludges Managed in Municipal Landfills''
document, the reviewers recommended more data and discussion on the
model methodology and results. EPA revised these documents
incorporating the peer reviewers' comments, where necessary and
appropriate. The docket contains the individual peer reviewer reports,
EPA's response to the peer reviewers' comments, and supporting
documents for the peer reviews.\1\ For more information about the peer
review process, see EPA's Peer Review Handbook at https://www.epa.gov/iris/Peer_Review_Handbook_2006_3rd_edition.pdf.
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\1\ The ``F001-F005 Solvent-Contaminated Wipes and Laundry
Sludge: Comparison of Landfill Loading Calculations and Risk-Based
Mass Loading Limits'' document was developed after completion of the
peer reviews.
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C. How were the Landfill Loadings for Solvent-Contaminated Wipes
Determined?
We began the evaluation by looking at the 30 solvents listed in 40
CFR 261.31 (F001-F005). Through literature review and site visits, we
eliminated 10 of these 30 solvents \2\ from the analysis. Of the 10
eliminated solvents, 5 are ozone-depleting or present other serious
hazards and are therefore banned or restricted from use. The other 5
solvents eliminated from the analysis may have been used on wipes in
the past; however, our research found that these solvents are currently
not used or are used only in limited quantities in conjunction with
wipes. The Agency solicits comment on this finding.
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\2\ Carbon tetrachloride, 1,1,1-Trichloroethane,
Trichlorofluoromethane, Dichlorodifluoromethane, 1,1,2-
Trichlorotrifluorethane (ozone depleting substances), Carbon
disulfide, ethyl ether, Nitrobenzene, 2-Nirtopropane, Pyridine (not
know to be used as solvents in wipes applications). For the
discussion on the solvents, see the ``Landfill Loadings Calculations
for Disposed Solvent-Contaminated Wipes and Laundry Sludge Managed
in Municipal Landfills'' Section 1.2.1 and 1.2.2.
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After identifying the remaining 20 solvents \3\ to evaluate, we
used both deterministic (point-value) and Monte Carlo (probabilistic)
methods in the analysis. We estimated the number of generators and the
number of wipes used by those generators. Few generators have the same
solvent use practices or use the same number of wipes. To account for
these differences, our revised risk analysis included an assessment of
the uncertainty using empirical data-based probability distributions in
a Monte Carlo analysis. We conducted a separate sensitivity analysis to
assess the influence that each input parameter has on the result. These
results identify the most and least influential assumptions. We
estimated the amount of solvent that could be on a wipe or in laundry
sludge before disposal and then estimated the number of generators
potentially disposing of solvent-contaminated wipes or laundry sludge
into a single MSWLF. Through our calculations, we derived estimated
landfill loadings for the solvents. The full report, ``Landfill
Loadings Calculations For Disposed Solvent-Contaminated Wipes and
Laundry Sludge Managed in Municipal Landfills'' describes the
assumptions made, methodologies used, and the results of the analysis.
The Docket (EPA-HQ-RCRA-2003-0004) for this NODA contains this
document.
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\3\ Acetone, benzene, butanol, chlorobenzene, cresols (total),
cyclohexanone, dichlorobenzene, 1, 2-ethoxyethanol, 2-ethyl acetate,
ethyl benzene, isobutanol, methanol, methyl ethyl ketone, methyl
isobutyl ketone, methylene chloride, tetrachloroethylene, toluene,
trichloroethane, 1,1,2-trichloroethylene, xylene (mixed isomers).
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D. How were the Risk-Based Mass Loadings Calculated?
We also developed a methodology to estimate the amount of hazardous
spent solvents that could be disposed of in MSWLFs (unlined and
composite lined), and be protective of human health and the environment
at the point of exposure. These ``allowable amounts'' are risk-based
mass loading rates expressed in kg of each spent solvent
[[Page 55166]]
that can be added to a landfill in a given year. These risk-based mass
loading rates were derived from modeling scenarios defined in terms of
the solvent, landfill type (e.g., lined or unlined), exposure pathway
(e.g., ambient air inhalation), contact media (e.g., groundwater), and
receptor (e.g., child or adult). Mass loading rates were estimated for
each solvent such that the exposure at the 50th and 90th percentiles of
the risk distribution would not exceed the identified risk target
criteria, if these materials were disposed of in a MSWLF. The 50th and
90th percentiles are typically used by the Agency to characterize risk.
The 90th percentile represents a ``high end'' estimate of individual
risk, while the 50th percentile results reflect the central tendency
estimate of the risk distribution.\4\ For this analysis, the risk
criteria were selected so that either 50 or 90 percent of the
hypothetical individuals living near a landfill will not be exposed to
solvent releases resulting in an excess lifetime cancer risk above 1
chance in 10,000 (10-4) through 1 chance in 1,000,000
(10-6).\5\ For noncancer health effects, we used a hazard
quotient (HQ) of one as our risk criterion (the noncancer HQ is defined
as the ratio of predicted intake levels to safe intake levels).
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\4\ Guidance for Risk Characterization, U.S. Environmental
Protection Agency, 1995.
\5\ These risk criteria are consistent with those discussed in
EPA's hazardous waste listing determination policy (see December 22,
1994; 59 FR 66072). Also see 40 CFR 300.430(e)(2)(i)(A)(2), which
establishes a cancer risk range of 10-4 to
10-6 in the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP) for responding to releases of
hazardous substances under Superfund.
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We identified the following exposure pathways based on the
solubility and volatility of the 20 spent solvents included in the
analysis, as well as the operating practices of nonhazardous waste
landfills:
(1) Inhalation of ambient air containing spent solvents emitted
from the landfill at residential dwellings;
(2) Ingestion of spent solvents that leach from the landfill and
migrate through groundwater to residential drinking water wells;
(3) Inhalation of spent solvents during showering and bathing with
solvent-contaminated groundwater; and
(4) Dermal contact of spent solvents during showering and bathing
with solvent-contaminated groundwater.
A probabilistic approach was used to develop national mass loading
rates because landfills that receive solvent-contaminated wipes and
laundry sludge could be of varying geometry and located in many
different parts of the country. The approach primarily addresses the
variability in waste management practices (that is, unlined and
composite lined landfills), environmental settings, and exposure-
related parameters. We also developed a landfill source model to
simulate the solvent-specific air emissions and leachate releases from
landfills. The quantity of solvent releases to the air and groundwater
were then used as inputs to the air and groundwater fate and transport
models.
For each solvent, we calculated risk estimates assuming a unitized
mass loading rate (1 kg per year) for each liner type, exposure
pathway, and receptor, as well as for the combined exposures associated
with groundwater uses. The risk results provide insight into the
relative nature of exposures and potential risks that could be
associated with the solvent-contaminated wipes disposed of in MSWLFs.
For unlined landfills, the groundwater pathways were always
associated with the highest predicted risks at the 50th and 90th
percentiles of the distributions. For composite lined landfills,
groundwater exposures were associated with the highest risks at the
90th percentile, except for methylene chloride and methyl ethyl ketone,
which showed higher risks for the ambient air inhalation pathway. At
the 50th percentile, the highest predicted risks were associated with
the ambient air inhalation pathway for 16 of the 20 solvents; however,
for unlined landfill disposal, the predicted risks were associated more
with drinking water.
From this information, we developed solvent-specific risk-based
mass loading rates (in kg/yr) that could be disposed of in a MSWLF and
meet specific risk criteria and be protective of human health and the
environment. The risk-based mass loading rates do not provide direct
insight into the potential impacts associated with current management
practices. The full report, ``Risk-Based Mass Loading Limits for
Solvents in Disposed Wipes and Laundry Sludges Managed in Municipal
Landfills'' describes the assumptions made, methodologies used, and the
results of the analysis. The Docket for this NODA (EPA-HQ-RCRA-2003-
0004) contains this document.
E. How were the Risk-Based Mass Loadings Compared to the Solvent-
Quantity Loadings?
To perform a comparison, EPA evaluated a 90th percentile risk
criterion for the risk-based mass loading limit to be protective of 90
percent of hypothetically exposed individuals across all of the
landfill sites in the United States (Guidance for Risk
Characterization, U.S. Environmental Protection Agency, 1995;
accessible at https://www.epa.gov/OSA/spc/pdfs/rcguide.pdf, which states
that ``For the Agency's purposes, high end risk descriptors are
plausible estimates of the individual risk for those persons at the
upper end of the risk distribution,'' or conceptually, individuals with
``exposure above about the 90th percentile of the population
distribution''). As recommended in the Guidance, EPA also evaluated the
50th percentile results as the central tendency estimate of that risk
distribution. Thus, we compared the 90th percentile estimate of
landfill loading rates (ELLRs) to the 90th percentile of the risk-based
mass loading levels (RB-MLLs) to determine whether the ELLRs in
landfills that can be attributed to solvent-contaminated wipes and
laundry sludge exceeds the RB-MLLs that correspond to selected health-
based limits. A similar comparison was conducted at the 50th
percentile.
F. What are the Results for the Comparison of the Loading Estimates?
The results for both the ELLR and the RB-MLL are generated from a
probabilistic analysis. The results from these two separate
calculations are given by a distribution of values. The theoretical
risk distribution provides the basis for calculating risk-based mass
loading rates for any percentile of that distribution. Based on the
risk criteria that EPA evaluated for the wipes analysis, the RB-MLL was
identified at the 50th and 90th percentiles of the distribution. These
levels represent the allowable mass loading rate (in kg per year) for
management of solvent-containing wipes and laundry sludges in a MSWLFs
anywhere in the country in any given year.
The comparisons of the ELLRs and RB-MLLs are expressed as ratios,
i.e., the 90th percentile ELLRs (kg solvent per year) are divided by
the 90th percentile RB-MLLs (kg solvent per year) for a specific
solvent to yield ratios. The ELLR is an estimate of the mass loading
into the landfill and the RB-MLL is an estimate of the mass loading
that would correspond to an exposure equivalent to the chosen risk
criterion, or risk ``target.'' Therefore, if the ratio exceeds one,
this indicates the degree to which the ELLR exceeds the evaluation
criteria used to establish the RB-MLLs (i.e., a cancer risk of 1 x
10-5 and an HQ of 1 for noncarcinogenic risk).
The comparison of the 90th percentile values of the ELLRs and the
RB-MLLs
[[Page 55167]]
indicates that 8 of the 20 spent solvents could pose potential risks
above EPA's evaluated criteria at some risk levels for unlined
landfills. The 90th percentile risks for benzene (using the high end
cancer risk value only), 1,1,2-trichloroethane, methylene chloride,
tetrachloroethylene, and trichloroethylene exceeded the 10-5
cancer risk criteria. The 90th percentile risks for chlorobenzene,
toluene, and xylenes exceeded the criteria for non-cancer health
effects (HQ = 1). As expected, the predicted risks for the unlined
landfill analysis were always greater than those for the composite-
lined landfill analysis. Using the comparison of the 90th percentile
results, the potential risks from all solvents examined in the
composite-liner scenario, except for tetrachloroethylene, were well
below (generally <0.1) the health-based criteria used in this analysis.
The value for tetrachloroethylene was 1.1 using the higher end cancer
risk value and 0.9 using the lower end cancer risk value. For a more
detailed explanation of how the ELLR and RB-MLL were compared, see the
``F001-F005 Solvent-Contaminated Wipes and Laundry Sludge: Comparison
of Landfill Loading Calculations and Risk Based Mass Loading Limits''
document in the docket for this NODA.
A comparison of the ELLR and RB-MLL central tendency values (50th
percentiles), showed that tetrachloroethylene is the only solvent in
the unlined landfill scenario that produced a ratio of ELLR to RB-MLL
greater than one (using a cancer risk of 1 x 10-5 and an HQ
of 1) and this value was 1.4 using the higher end cancer risk value;
using the lower end cancer risk value, the ratio was 1.2. For the
composite liner scenario, all ratios of the 50th percentile ELLRs and
RB-MLLs are well below one using these risk criteria.
The ratios from a comparison of the ELLRs and the RB-MLLs for the
constituents with carcinogenic risk would change if the RB-MLLs were
calculated using a risk criterion different from the 1 x
10-5 criterion. If a target risk level of 1 x
10-4 were used for calculating the RB-MLLs, the carcinogenic
risk for the carcinogens (1,1,2-trichloroethane, benzene, methylene
chloride, tetrachloroethylene, and trichloroethylene) would be lower by
a factor of ten. Alternatively, if a target risk level of 1 x
10-6 were used, the cancer risks for these constituents
would be higher by a factor of ten. A comparison of the ELLR and RB-MLL
values using the 10-4 risk criterion for the no-liner
scenario would have the effect of lowering the ratios; however, the
ratios of 7 of the 8 solvents of potential concern would remain above
one at the 90th percentile (the ratio for benzene would be less than
one). Using the 10-4 criterion at the 50th percentile, the
ratios for all the solvents would be below one. Using the
10-6 risk criterion would have the effect of raising the
ratios in the unlined landfill scenario for carcinogens, such that the
ratios for all these 8 solvents for the 90th percentile results would
exceed one by a wider margin. Using the 10-6 risk criterion,
the ratios from the 50th percentile results would increase for the
carcinogenic solvents, such that the ratios for tetrachloroethylene and
trichloroethylene would exceed one at the 50th percentiles.
For the composite-liner scenario, the ratios for all solvents would
be below one (including tetrachloroethylene) at both the 90th and 50th
percentiles using the 10-4 risk criterion. Using the
10-6 criterion, the ratios for tetrachloroethylene and
trichloroethylene at the 90th percentile are above one.
These results differ from our original risk screening analysis for
the proposed rule in the following ways:
The number of solvents that show a potential risk for
disposal in an unlined landfill in our risk screening analysis
increased by 2 in the revised analysis and the solvents indicating a
potential risk also changed.\6\
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\6\ Solvents in the proposal indicating a potential risk in
unlined landfill scenario: Methyl ethyl ketone, methyl isobutyl
ketone, nitrobenzene, pyridine, methylene chloride, 2-nitroproane.
Solvents from revised risk analysis indicating a potential risk in
unlined landfill scenario: benzene, 1,1,2-trichloroethane,
chlorobenzene, methylene chloride, tetrachloroethylene, toluene,
trichloroethylene, and xylene.
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In the original risk screening analysis, we did not
consider risks from lined landfills. The revised risk analysis does
consider risks from composite lined non-hazardous waste landfills.
In the original risk screening analysis, we did not
identify any solvents of concern from laundry sludge. Our revised risk
analysis indicates that tetrachloroethylene may be a concern in both
solvent-contaminated wipes and laundry sludge disposed of in unlined
and composite lined landfills.
G. Request for Comment
We are seeking comment on all aspects of the revised risk analysis
(landfill loading calculations, risk based mass loading levels,
comparison document). In particular, we are seeking comment on:
--The assumptions used;
--Whether the uncertainties are properly acknowledged and
mitigated, as appropriate;
--The data used;
--The methodology used; and
--How the agency should consider using the results of the revised
risk analysis in its decision-making.
III. Discussion and Request for Comment on Management Approaches and
Risk Analysis Findings
The Agency's November 2003 proposal allowed solvent-contaminated
wipes and laundry sludge that met certain conditions to be sent either
to a MSWLF or to another nonhazardous waste landfill that meets the
standards under 40 CFR part 257, subpart B. We did not discuss the
specific characteristics of MSWLFs receiving solvent-contaminated wipes
or laundry sludge, specifically whether the landfill would be unlined
or lined. Because our revised risk analysis indicates that a number of
solvents show a potential for risk in unlined landfills (using the 90th
percentile results and a risk criterion of 1 x 10-\5\ for
cancer risk), we are considering two additional approaches for managing
solvent-contaminated wipes and laundry sludge in landfills.
The first approach would allow the disposal of solvents not showing
a risk in any municipal landfill or nonhazardous waste landfill whether
lined or unlined. The solvents that indicated a potential risk if
disposed of in an unlined landfill \7\ could only be disposed in a
lined municipal landfill or lined non-hazardous waste landfill. This
could be accomplished by requiring disposal in a Subtitle D municipal
or industrial landfill unit subject to, or otherwise meeting, the
landfill requirements in 40 CFR 258.40(a)(2) and (b).8 9 The
second approach would be to
[[Page 55168]]
establish conditions that allow all solvent-contaminated wipes, no
matter which solvent they contain, except perhaps tetrachloroethylene,
to be sent to a Subtitle D municipal or industrial landfill unit
subject to, or otherwise meeting, the landfill requirements in Sec.
258.40(a)(2) and (b). This approach could be simpler since the
generator would not need to separate his wipes and send them to
separate disposal locations. We are requesting comment on these two
approaches.
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\7\ Benzene, 1,1,2-trichloroethane, chlorobenzene, methylene
chloride, toluene, trichloroethylene, and xylene.
\8\ 40 CFR 258.40(a)(2) states: ``With a composite liner, as
defined in paragraph (b) of this section and a leachate collection
system that is designed and constructed to maintain less than a 30-
cm depth of leachate over the liner. 40 CFR 258.40(b) states ``For
purposes of this section, composite liner means a system consisting
of two components; the upper component must consist of a minimum 30-
mil flexible membrane liner (FML), and the lower component must
consist of at least a two-foot layer of compacted soil with a
hydraulic conductivity of no more than 1 x 10-\7\cm/sec.
FML components consisting of high density polyethylene (HDPE) shall
be at least 60-mil thick. The FML component must be installed in
direct and uniform contact with the compacted soil component.''
\9\ Solvent-contaminated wipes, while not required, could also
be disposed of in a hazardous waste landfill meeting the landfill
requirements in 40 CFR 264.301 or 265.301.
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The risk analysis using 90th percentile results also indicates that
tetrachloroethylene has a risk potential in both unlined landfills and
composite lined landfills for both solvent-contaminated wipes and
laundry sludge (using a cancer risk criterion of 1 x
10-\5\). Using the higher end cancer risk value in our
analysis, the ratio of the ELLR to the RB-MLL for tetrachloroethylene
was 1.1, while using the lower end cancer risk value the ratio was 0.9.
If we rounded the numbers, the ratios would both be 1.0. Since we
generally used a conservative approach in the risk analysis, we are
asking for comment on whether our results represent a risk of concern.
Even though the risk may be borderline, we are considering
alternative management conditions for tetrachloroethylene to address
this potential risk. One approach is to prohibit disposal of
tetrachloroethylene, either on solvent-contaminated wipes or in laundry
sludge that exhibits the tetrachloroethylene toxicity characteristic
(TC) in nonhazardous waste landfills. Another approach could be
eliminating wipes contaminated with tetrachloroethylene from the scope
of the final exclusions for solvent-contaminated wipes, or eliminating
wipes contaminated with tetrachloroethylene that exhibit the TC in the
scope of the final exclusions for solvent-contaminated wipes. We are
requesting comment on these approaches or other possible alternatives.
IV. Conclusion
We will consider comments received on the revised risk analysis and
then modify the analysis as appropriate. The final risk analysis,
comments submitted in response to Section III of this notice, and
comments submitted in response to the November 2003 proposed rule will
be considered as we develop a final rule for the management of solvent-
contaminated wipes.
Readers should note that other than the specific issues identified
in this NODA, no other issues discussed in or related to the November
20, 2003, proposed rule are open for further comment and the Agency
will not respond to any comments received on any issues not identified
in this NODA.
Dated: October 15, 2009.
Mathy Stanislaus,
Assistant Administrator, Office of Solid Waste and Emergency Response.
[FR Doc. E9-25812 Filed 10-26-09; 8:45 am]
BILLING CODE 6560-50-P