Hazardous Waste Management System; Identification and Listing of Hazardous Waste; Dye and Pigment Industries; Land Disposal Restrictions for Newly Identified Wastes; CERCLA Hazardous Substance Designation and Reportable Quantities
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Federal Register › Vol. 64 › 64 FR 40192
Text
Part VI
Environmental Protection Agency
_______________________________________________________________________
40 CFR Parts 148, 261 et al.
Hazardous Waste Management System; Identification and Listing of
Hazardous Waste; Dye and Pigment Industries; Land Disposal Restrictions
for Newly Identified Wastes; CERCLA Hazardous Substance Designation and
Reportable Quantities; Proposed Rule
Proposed Rules
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 148, 261, 268, 271, and 302
[SWH-FRL-6373-4]
RIN 2050-AD80
Hazardous Waste Management System; Identification and Listing of
Hazardous Waste; Dye and Pigment Industries; Land Disposal Restrictions
for Newly Identified Wastes; CERCLA Hazardous Substance Designation and
Reportable Quantities
AGENCY: Environmental protection agency (EPA).
ACTION: Notice of Proposed Rulemaking.
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SUMMARY: The EPA is proposing to list two of three wastes from the dyes
and pigment industries as hazardous wastes under the Resource,
Conservation, and Recovery Act (RCRA), which direct EPA to determine
whether certain wastes from the dye and pigment industries present a
hazard to human health or the environment. The effect of listing these
wastes will be to subject them to stringent management and treatment
standards and to emergency notification requirements if there are
releases of these hazardous wastes to the environment. EPA is proposing
concentration-based listings for the two wastes, such that waste
generators have the option of determining that their specific waste is
nonhazardous. To have their waste classified as nonhazardous,
generators must determine the levels of constituents in their wastes,
and certify to EPA that their wastes are below the regulatory levels of
concern.
s wastes to the environment. EPA is proposing
concentration-based listings for the two wastes, such that waste
generators have the option of determining that their specific waste is
nonhazardous. To have their waste classified as nonhazardous,
generators must determine the levels of constituents in their wastes,
and certify to EPA that their wastes are below the regulatory levels of
concern.
DATES: EPA will accept public comments on this proposed rule until
September 21, 1999; comments postmarked after this date will be marked
``late'' and may not be considered. Any person may request a public
hearing on this proposal by filing a request with Mr. David Bussard,
whose address appears below, by August 6, 1999.
ADDRESSES: If you wish to comment on this proposed rule, you must send
an original and two copies of the comments referencing docket number F-
1999-DPIP-FFFFF to: RCRA Docket Information Center, Office of Solid
Waste (5305G), U.S. Environmental Protection Agency Headquarters (EPA,
HQ), 401 M Street, SW, Washington, DC 20460. Hand deliveries of
comments should be made to the Arlington, VA, address listed below. You
may also submit comments electronically by sending electronic mail
through the Internet to: [email protected]. See the beginning
of Supplementary Information for instructions on electronic submission.
You should not submit electronically any confidential business
information (CBI). You must submit an original and two copies of CBI
under separate cover to: RCRA CBI Document Control Officer, Office of
Solid Waste (5305W), U.S. EPA, 401 M Street, SW, Washington, DC 20460.
See the beginning of Supplementary Information for information of
viewing public comments and supporting materials.
Address requests for a hearing to Mr. David Bussard at: Office of
Solid Waste, Hazardous Waste Identification Division (5304W), U.S.
Environmental Protection Agency 401 M Street, SW, Washington, DC 20460,
f
Solid Waste (5305W), U.S. EPA, 401 M Street, SW, Washington, DC 20460.
See the beginning of Supplementary Information for information of
viewing public comments and supporting materials.
Address requests for a hearing to Mr. David Bussard at: Office of
Solid Waste, Hazardous Waste Identification Division (5304W), U.S.
Environmental Protection Agency 401 M Street, SW, Washington, DC 20460,
(703)308-8880.
FOR FURTHER INFORMATION CONTACT: For general information, contact the
RCRA Hotline at (800) 424-9346 or TDD (800) 553-7672 (hearing
impaired). In the Washington, DC, metropolitan area, call (703) 412-
9810 or TDD (703) 412-3323. For information on specific aspects of the
rule, contact Narendra Chaudhari or Robert Kayser, Office of Solid
Waste (5304W), U.S. Environmental Protection Agency, 401 M Street, SW,
Washington, DC 20460. [E-mail addresses and telephone numbers:
[email protected], (703) 308-0454;
[email protected], (703) 308-7304)].
SUPPLEMENTARY INFORMATION: You should identify comments in electronic
format with the docket number F-1999-DPIP-FFFFF. You must submit all
electronic comments as an ASCII (text) file, avoiding the use of
special characters and any form of encryption. If you do not submit
comments electronically, EPA is asking prospective commenters to
voluntarily submit one additional copy of their comments on labeled
personal computer diskettes in ASCII (text) format or a word processing
format that can be converted to ASCII (text). It is essential to
specify on the disk label the word processing software and version/
edition as well as the commenter's name. This will allow EPA to convert
the comments into one of the word processing formats utilized by the
Agency. Please use mailing envelopes designed to physically protect the
submitted diskettes. EPA emphasizes that submission of comments on
diskettes is not mandatory, nor will it result in any advantage or
disadvantage to any commenter
tware and version/
edition as well as the commenter's name. This will allow EPA to convert
the comments into one of the word processing formats utilized by the
Agency. Please use mailing envelopes designed to physically protect the
submitted diskettes. EPA emphasizes that submission of comments on
diskettes is not mandatory, nor will it result in any advantage or
disadvantage to any commenter. Supporting documents in the docket for
this Notice are also available in electronic format on the Internet.
Follow these instructions to access these documents.
WWW: http://www.epa.gov/epaoswer/hazwaste/id
FTP: ftp.epa/gov
Login: anonymous
Password: your Internet address
Files are located in /pub/gopher/OSWRCRA.
EPA will keep the official record for this action in paper form.
Accordingly, we will transfer all comments received electronically into
paper form and place them in the official record, which will also
include all comments submitted directly in writing. The official record
is the paper record maintained at the address in ADDRESSES at the
beginning of this document.
EPA responses to comments, whether the comments are written or
electronic, will be in a notice in the Federal Register or in a
response to comments document placed in the official record for this
rulemaking. We will not immediately reply to commenters electronically
other than to seek clarification of electronic comments that may be
garbled in transmission or during conversion to paper form, as
discussed above.
You may view public comments and supporting materials in the RCRA
Information Center (RIC), located at Crystal Gateway I, First Floor,
1235 Jefferson Davis Highway, Arlington, VA. The RIC is open from 9
a.m. to 4 p.m., Monday through Friday, excluding federal holidays. To
review docket materials, we recommend that you make an appointment by
calling (703) 603-9230. You may copy a maximum of 100 pages from any
regulatory docket at no charge. Additional copies cost $0.15/page
er (RIC), located at Crystal Gateway I, First Floor,
1235 Jefferson Davis Highway, Arlington, VA. The RIC is open from 9
a.m. to 4 p.m., Monday through Friday, excluding federal holidays. To
review docket materials, we recommend that you make an appointment by
calling (703) 603-9230. You may copy a maximum of 100 pages from any
regulatory docket at no charge. Additional copies cost $0.15/page. For
information on accessing paper and/or electronic copies of the
document, see the Supplementary Information section.
How Can I Influence EPA's Thinking on This Proposed Rule?
In developing this proposal, we tried to address the concerns of
all our stakeholders. Your comments will help us improve this rule. We
invite you to provide different views on options we propose, new
approaches we haven't considered, new data, how this proposed rule may
effect you, or other relevant information. We welcome your views on all
aspects of this proposed rule, but request comments on specific issues
throughout this notice. We grouped these specific requests near the end
of the sections in which we discuss the relevant issues. Your comments
will be most effective if you follow the suggestions below:
Explain your views and reasoning as clearly as possible.
Provide solid technical and cost data to support your
views.
If you estimate potential costs, explain how you arrived
at the estimate.
Tell us which parts you support, as well as those with
which you disagree.
Provide specific examples to illustrate your concerns.
Offer specific alternatives.
Refer your comments to specific sections of the proposal,
such as the units or page numbers of the preamble, or the regulatory
sections.
Be sure to include the name, date, and docket number with
your comments.
Contents of This Proposed Rule
The following outline lists the contents of the preamble to this
proposed rule:
ic examples to illustrate your concerns.
Offer specific alternatives.
Refer your comments to specific sections of the proposal,
such as the units or page numbers of the preamble, or the regulatory
sections.
Be sure to include the name, date, and docket number with
your comments.
Contents of This Proposed Rule
The following outline lists the contents of the preamble to this
proposed rule:
I. Overview
A. Who Would Potentially be Affected by This Proposed Rule?
B. Why Does This Proposed Rule Read Differently From Other
Listing Rules?
C. What Are the Statutory Authorities for This Proposed Rule?
II. Background
A. How Does EPA Define a Hazardous Wastes?
B. What Industries Are Covered in This Proposed Rule?
C. Confidential Business Information (CBI) Issues Regarding This
Rule
D. What Wastes Are Covered in Today's Proposed Rule?
E. What Information Did EPA Collect and Use?
III. Approach Used in This Proposed Listing
A. Summary of Today's Action
B. What Is a Concentration-Based Listing?
C. Why Is a Concentration-Based Approach Being Used for This
Listing?
D. What Risk Assessment Approach Did EPA Use?
E. How Did EPA Estimate Exposure Concentrations?
F. What Exposure Assumptions and Toxicity Levels Did EPA Use?
G. What Uncertainties Are Associated With the Risk Assessment?
H. What Risk Level Do the Concentration Levels Represent?
I. What Are the Proposed Listing Levels?
IV. Proposed Listing Determinations and Regulations
A. What Are the Proposed Regulations for the Two Wastes?
B. What Are We Proposing for Anthraquinone Sludges?
C. What Is the Status of Landfill Leachate From Previously
Disposed Wastes?
V. Generator Requirements for Implementation of Concentration-Based
Listings
A. Do I Have to Determine Whether or Not My Waste Is Hazardous?
B. How Do I Manage My Waste During the Period Between the
Effective Date of the Final Rule and Initial Hazardous Waste
Determination for My Waste?
C. What Are the Steps I Must Follow to Determine Whether or Not
My Waste Is Hazardous?
D
isposed Wastes?
V. Generator Requirements for Implementation of Concentration-Based
Listings
A. Do I Have to Determine Whether or Not My Waste Is Hazardous?
B. How Do I Manage My Waste During the Period Between the
Effective Date of the Final Rule and Initial Hazardous Waste
Determination for My Waste?
C. What Are the Steps I Must Follow to Determine Whether or Not
My Waste Is Hazardous?
D. What Are the Requirements for a Waste Determined to be
Nonhazardous, and How Do I Claim My Waste to Be Nonhazardous?
E. What Records Am I Required to Keep On-site to Support a
Nonhazardous Claim for My Waste?
F. What Happens if I Do Not Meet the Notification and
Recordkeeping Requirements for a Waste That I Have Determined to be
Nonhazardous?
G. What Are the Follow-up Waste Analysis Requirements for My
Nonhazardous Waste?
H. What Happens If My Waste Constituent Concentrations Are No
Longer Below the Listing Concentrations?
I. Can I Treat My Waste to Below Listing Concentrations and Then
Claim My Waste to Be Nonhazardous?
J. Alternative Implementation Approach
VI. Proposed Treatment Standards Under RCRA's Land Disposal
Restrictions
A. What are EPA's Land Disposal Restrictions (LDRs)?
B. How Does EPA Develop LDR Treatment Standards?
C. What Treatment Standards Are Proposed?
D. Other LDR-Related Provisions
E. Is There Treatment and Management Capacity Available for
These Proposed Newly Identified Wastes
VII. State Authority and Compliance
A. How Are States Authorized Under RCRA?
B. What Is the Effect of Today's Proposal on State
Authorizations?
C. Who Must Notify EPA That They Have a Hazardous Waste?
D. What Do Generators and Transporters Have to Do?
E. Which Facilities Are Subject to Permitting?
VIII. CERCLA Designation and Reportable Quantities
A. What Is the Relationship Between RCRA and CERCLA?
B. Is EPA Proposing to Add Dye and Pigment Production Wastes to
CERCLA?
C. Is EPA Proposing to Adjust the Statutory One Pound RQ for
K167 and K168 Wastes?
D
That They Have a Hazardous Waste?
D. What Do Generators and Transporters Have to Do?
E. Which Facilities Are Subject to Permitting?
VIII. CERCLA Designation and Reportable Quantities
A. What Is the Relationship Between RCRA and CERCLA?
B. Is EPA Proposing to Add Dye and Pigment Production Wastes to
CERCLA?
C. Is EPA Proposing to Adjust the Statutory One Pound RQ for
K167 and K168 Wastes?
D. When Do I Need to Report a Release of K167 and K168 Wastes
Under CERCLA?
E. How Do I Report a Release?
F. What Is the Statutory Authority for This Program?
IX. Analytical and Regulatory Requirements
A. Is This a Significant Regulatory Action? (Executive Order
12866)
B. Why Is This Proposed Rule Necessary?
C. What Regulatory Options Were Considered?
D. What Are the Potential Cost Impacts of Today's Proposed Rule?
E. What Are the Potential Economic Impacts to Industry From the
Proposed Rule?
F. What Are the Potential Benefits From the Proposed Rule?
G. What Consideration Was Given to Small Entities?
H. What Consideration Was Given to Children's Health?
I. What Consideration Was Given to Environmental Justice?
J. What Consideration Was Given to Unfunded Mandates?
K. What Consideration Was Given to Tribal Governments Analysis?
L. Was the National Technology Transfer and Advancement Act
Considered?
M. How is the Paperwork Reduction Act Considered in Today's
Proposal?
I. Overview
A. Who Would Potentially Be Affected by This Proposed Rule?
The action, if finalized, could potentially affect those who handle
the waste streams proposed for listing on EPA's RCRA list of hazardous
wastes. This action may also affect entities that may need to respond
to releases of these wastes as CERCLA hazardous substances. Those
affected may include:
d in Today's
Proposal?
I. Overview
A. Who Would Potentially Be Affected by This Proposed Rule?
The action, if finalized, could potentially affect those who handle
the waste streams proposed for listing on EPA's RCRA list of hazardous
wastes. This action may also affect entities that may need to respond
to releases of these wastes as CERCLA hazardous substances. Those
affected may include:
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Category Affected entities
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Industry..................... Generators of the following listed
wastes, or entities that treat, store,
transport, or dispose of these wastes or
materials derived from them.
K167 Spent filter aids, diatomaceous
earth, or adsorbents used in the
production of azo, anthraquinone, or
triarylmethane dyes, pigments, or FD&C
colorants.
K168 Wastewater treatment sludges from
the production of triarylmethane dyes
and pigments (excluding triarylmethane
pigments using aniline as a feedstock).
State, Local, Tribal Govt.... State and Local Emergency Planning
entities.
Federal Govt................. National Response Center, and any Federal
Agency that handle the listed waste or
chemical.
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We do not intend this table to be exhaustive, but rather our aim is
to provide a guide for readers regarding entities likely to be
regulated by this action. This table lists those entities that EPA now
is aware potentially could be
tional Response Center, and any Federal
Agency that handle the listed waste or
chemical.
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We do not intend this table to be exhaustive, but rather our aim is
to provide a guide for readers regarding entities likely to be
regulated by this action. This table lists those entities that EPA now
is aware potentially could be
affected by this action. However, this action may affect other entities
not listed in the table. To determine whether your facility is
regulated by this action, you should examine 40 CFR parts 260 and 261
carefully in concert with the amended rules found at the end of this
Federal Register document. Furthermore, we are proposing this rule as a
concentration-based listing, such that waste generators have the option
of determining that their specific waste is nonhazardous (see Sections
IV and V of today's rule). If you have questions regarding the
applicability of this action to a particular entity, consult the person
listed in the preceding section entitled FOR FURTHER INFORMATION
CONTACT.
B. Why Does This Proposed Rule Read Differently From Other Listing
Rules?
Today's proposed listing determination preamble and regulations are
written in ``readable regulations'' format. The authors tried to use
active rather than passive voice, plain language, a question-and-answer
format, the pronouns ``we'' for EPA and ``you'' for the owner/
generator, and other techniques to make the information in today's
proposed rule easier to read and understand. This new format is part of
the Agency's efforts at regulatory reinvention, and it makes today's
proposed rule read differently from other listing rules. The Agency
believes that this new format will increase readers' abilities to
understand the regulations, which should then increase compliance, make
enforcement easier, and foster better relationships between EPA and the
regulated community
This new format is part of
the Agency's efforts at regulatory reinvention, and it makes today's
proposed rule read differently from other listing rules. The Agency
believes that this new format will increase readers' abilities to
understand the regulations, which should then increase compliance, make
enforcement easier, and foster better relationships between EPA and the
regulated community.
All of the requirements found in today's proposed regulations would
constitute binding, enforceable legal requirements. The plain language
format used in today's proposed regulations may appear different from
other rules, but it would establish binding, enforceable legal
requirements just as those in the existing regulations.
C. What Are the Statutory Authorities for This Proposed rule?
EPA is proposing these regulations under the authority of Sections
2002(a), 3001 (a), (b) and (e)(2), 3004 (g) and (m), and 3007(a) of the
Solid Waste Disposal Act (commonly referred to as RCRA), as amended by
the Hazardous and Solid Waste Amendments of 1984 (HSWA). These statutes
are codified in Volume 42 of the United States Code (U.S.C.), sections
6901 to 6992(k).
Section 102(a) of the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), 42 U.S.C. 9602(a), is
the authority for the CERCLA aspects of this proposed rule.
II. Background
A. How Does EPA Define a Hazardous Waste?
EPA's regulations establish two ways of identifying wastes as
hazardous under RCRA. Wastes may be hazardous either if they exhibit
certain properties (``characteristics''), or if the wastes are included
on a specific list of wastes EPA has determined are hazardous
(``listing'' a waste as hazardous). EPA's regulations in the Code of
Federal Regulations (40 CFR) Secs. 261.20 through 261.24 define
characteristic wastes. These regulations classify wastes that exhibit
certain properties as having the characteristic of ignitability,
corrosivity, reactivity, or toxicity
if the wastes are included
on a specific list of wastes EPA has determined are hazardous
(``listing'' a waste as hazardous). EPA's regulations in the Code of
Federal Regulations (40 CFR) Secs. 261.20 through 261.24 define
characteristic wastes. These regulations classify wastes that exhibit
certain properties as having the characteristic of ignitability,
corrosivity, reactivity, or toxicity. As a generator, you must identify
wastes as characteristic wastes by sampling a waste, or by using
appropriate company records concerning the nature of the waste, to
determine whether a waste has the relevant properties (see
Sec. 262.11(c)). There is no regulatory requirement to conduct
sampling, but persons improperly managing materials that are found to
be characteristic hazardous wastes are subject to enforcement actions
under RCRA.
EPA may ``list'' wastes as hazardous if we conclude that the waste
is capable of posing a substantial present or potential hazard to human
health or the environment when improperly managed. We have established
criteria for listing a hazardous waste at 40 CFR 261.11(a)(3) for
wastes that contain hazardous constituents identified in Appendix VIII
of 40 CFR part 261. In deciding whether a wastes poses a substantial
hazard, we consider the factors given in Sec. 261.11(a)(3). We place
constituents in Appendix VIII if scientific studies have shown a
chemical has toxic effects on life forms (see 261.11(a)(3)). When
listing a waste, we also add the hazardous constituents that serve as
the basis for listing to Appendix VII to part 261.
The regulations at 40 CFR 261.31 through 261.33 contain the various
hazardous wastes the Agency has listed to date. Section 261.31 lists
wastes generated from non-specific sources, known as ``F-wastes,'' and
contains wastes that are usually generated by various industries or
types of facilities, such as ``wastewater treatment sludges from
electroplating operations'' (see code F006)
part 261.
The regulations at 40 CFR 261.31 through 261.33 contain the various
hazardous wastes the Agency has listed to date. Section 261.31 lists
wastes generated from non-specific sources, known as ``F-wastes,'' and
contains wastes that are usually generated by various industries or
types of facilities, such as ``wastewater treatment sludges from
electroplating operations'' (see code F006). Section 261.32 lists
hazardous wastes generated from specific industry sources, known as
``K-wastes,'' such as ``Spent potliners from primary aluminum
production'' (see code K088). Section 261.33 contains lists of
commercial chemical products and other materials that become hazardous
wastes, known as ``P-wastes'' or ``U-wastes,'' when they are discarded
or intended to be discarded.
The proposed regulations in today's notice would list wastes from a
specific industry and thus these wastes would be added to Sec. 261.32
with K-waste codes. We are proposing to add constituents that serve as
the basis for the proposed listings to Appendix VII, Part 261. For the
chemicals not already listed on the list of Hazardous Constituents in
Appendix VIII, we are also proposing to add these chemicals to that
list.
Wastes listed as hazardous are subject to federal requirements
under RCRA. These regulations affect persons who generate, transport,
treat, store or dispose of such waste. Facilities that must meet the
hazardous waste management requirements, including the need to obtain
permits to operate, commonly are referred to as Subtitle C facilities.
Subtitle C is Congress' original statutory designation for that part of
RCRA that directs EPA to issue those regulations for hazardous wastes
as may be necessary to protect human health or the environment. EPA
standards and procedural regulations implementing Subtitle C are found
generally at 40 CFR Parts 260 through 272.
Solid wastes that are not hazardous wastes may be disposed of at
facilities that are overseen by state and local governments
for that part of
RCRA that directs EPA to issue those regulations for hazardous wastes
as may be necessary to protect human health or the environment. EPA
standards and procedural regulations implementing Subtitle C are found
generally at 40 CFR Parts 260 through 272.
Solid wastes that are not hazardous wastes may be disposed of at
facilities that are overseen by state and local governments. These are
the so-called Subtitle D facilities, which generally impose less
stringent requirements on management of wastes. Subtitle D is Congress'
original statutory designation for that part of RCRA that deals with
disposal of solid waste. EPA regulations affecting Subtitle D
facilities are found generally at 40 CFR Parts 240 thru 247, and 255
thru 258. Regulations for Subtitle D landfills that accept municipal
waste (``municipal solid waste landfills'') are given in Part 258.
Residuals from the treatment, storage, or disposal of most listed
hazardous wastes are also classified as hazardous wastes based on the
``derived-from'' rule (40 CFR 261.3(c)(2)(i)). For example, ash or
other residuals from treatment of the listed wastes generally carry the
original waste code and are subject to the hazardous waste regulations.
Also, the ``mixture'' rule (40 CFR 261.3(a)(2)(iv)) provides that, with
certain limited exceptions, any mixture of a listed hazardous waste and
a solid waste is itself a RCRA hazardous waste. However, when these
wastes are recycled as described in 40 CFR 261.2(e)(1)(iii) or
261.4(a)(8), they are
astes generally carry the
original waste code and are subject to the hazardous waste regulations.
Also, the ``mixture'' rule (40 CFR 261.3(a)(2)(iv)) provides that, with
certain limited exceptions, any mixture of a listed hazardous waste and
a solid waste is itself a RCRA hazardous waste. However, when these
wastes are recycled as described in 40 CFR 261.2(e)(1)(iii) or
261.4(a)(8), they are
not solid wastes and are not subject to hazardous waste regulations.
For example, if a waste is collected and returned in a closed-loop
fashion to the same process, the waste is not regulated.
All RCRA hazardous wastes are also hazardous substances under the
Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA), as described in section 101(14)(C) of the CERCLA statute.
This applies to wastes listed in 261.31 through 261.33, as well as any
wastes that exhibit a RCRA characteristic. Table 302.4 at 40 CFR 302.4
lists CERCLA hazardous substances along with their reportable
quantities (RQs). Anyone spilling or releasing a substance at or above
the RQ must report this to the National Response Center, as required in
CERCLA Section 103. In addition, Section 304 of the Emergency Planning
and Community Right-to-Know Act (EPCRA) requires facilities to report
the release of a CERCLA hazardous substance at or above its RQ to State
and local authorities. Today's rule proposes to establish RQs for the
newly listed wastes. EPA is not taking action at this time to adjust
the one-pound statutory RQs for the newly listed hazardous substances.
B. What Industries Are Covered in This Proposed Rule?
ity Right-to-Know Act (EPCRA) requires facilities to report
the release of a CERCLA hazardous substance at or above its RQ to State
and local authorities. Today's rule proposes to establish RQs for the
newly listed wastes. EPA is not taking action at this time to adjust
the one-pound statutory RQs for the newly listed hazardous substances.
B. What Industries Are Covered in This Proposed Rule?
1. The Dye and Pigment Industries
Today's proposal applies to the manufacturers of organic dyes and
pigments, and does not affect producers of only inorganic dyes or
pigments. We have already issued final rules governing the
manufacturing of inorganic pigments. Section 261.32 contains wastes
codes K002 through K008 that list wastewater treatment sludges and
other residues from the production of inorganic pigments.
The organic dye and pigment industries are comprised of three
related industries, dye manufacturers, pigment manufacturers, and Food,
Drug, and Cosmetic (FD&C) colorant manufacturers. Dyes are colored or
fluorescent organic substances which impart color to a substrate. When
a dye is applied, it penetrates the substrate in a soluble form, after
which it may or may not become insoluble. Dyes are used to color
fabrics, leather, paper, ink, lacquers, varnishes, plastics, cosmetics,
and some food items. Dye manufacture in the U.S. includes more than
2,000 individual dyes, the majority of which are produced in quantities
of less than 50,000 pounds. The U.S. International Trade Commission's
(USITC) production data for 1994 showed total production of
approximately 156,000 tons for all organic dyes.
Organic pigments possess unique characteristics that distinguish
them from dyes and other colorants. The primary difference between
pigments and dyes is that, during the application process, pigments are
usually insoluble in the substrate. Pigments also retain a crystalline
or particulate structure and impart color by selective absorption or by
scattering of light
tons for all organic dyes.
Organic pigments possess unique characteristics that distinguish
them from dyes and other colorants. The primary difference between
pigments and dyes is that, during the application process, pigments are
usually insoluble in the substrate. Pigments also retain a crystalline
or particulate structure and impart color by selective absorption or by
scattering of light. This is different from dyes, which impart color by
selective absorption. Pigments are used in a variety of applications;
the primary use is in printing inks. There are fewer pigments produced
than dyes, though pigment batches are generally larger in size. The
USITC publication, Industry and Trade Summary: Synthetic Organic
Pigments, USITC (No. 3021, February 1997), indicates that the total
U.S. production was an estimated 71,500 tons of organic pigments in
1995.
FD&C colorants are dyes and pigments that have been approved by the
Food and Drug Administration (FDA) for use in food items, drugs, and/or
cosmetics. Typically, FD&C colorants are azo or triarylmethane dyes and
are similar or identical to larger-volume dye products not used in
food, drugs, and cosmetics. Manufacture of FD&C colorants is typically
the same as that for the corresponding dye or pigment, except that the
colorant undergoes additional purification. Each FD&C colorant batch is
tested and certified by the FDA.
2. Previous Regulations of Wastes From This Industry
The 1984 Hazardous and Solid Waste Amendments (HSWA) to RCRA
require EPA to make listing determinations for wastes from the
production of dyes and pigments (see RCRA section 3001(e)(2)). On June
1991 EPA entered into a proposed consent decree in a lawsuit filed by
the Environmental Defense Fund (EDF v. Browner, Civ. No. 89-0598
(D.D.C.), hereafter referred to as the consent decree). The consent
decree sets out a series of deadlines for promulgating RCRA listing
decisions, and has been amended as necessary. Paragraph 1h
ction of dyes and pigments (see RCRA section 3001(e)(2)). On June
1991 EPA entered into a proposed consent decree in a lawsuit filed by
the Environmental Defense Fund (EDF v. Browner, Civ. No. 89-0598
(D.D.C.), hereafter referred to as the consent decree). The consent
decree sets out a series of deadlines for promulgating RCRA listing
decisions, and has been amended as necessary. Paragraph 1h. of the
consent decree obligates EPA to determine whether or not to list as
hazardous certain wastes from the production of dyes and pigments.
In the consent decree EPA agreed to examine wastes from the
manufacture of three classes of dyes and pigments for regulation: azo/
benzidine, anthraquinone, and triarylmethane. The agreement specifies
that the listing determination is to address wastes from the azo,
monoazo, diazo, triazo, polyazo, azoic, and benzidine categories of the
azo/benzidine dye and pigment class; the anthraquinone and perylene
categories of the anthraquinone dye and pigment class; and the
triarylmethane, triphenylmethane, and pyrazolone categories of the
triarylmethane dye and pigment class. The settlement agreement also
specifies that the listing determination is to address the following
specific types of wastes where they are found: spent catalysts, reactor
still overheads, vacuum system condensate, process waters, spent
adsorbent, equipment cleaning sludge, product mother liquor, product
standardization filter cake, dust collector filter fines, recovery
still bottoms, treated wastewater effluent, and wastewater treatment
sludge.
Due to the market demand for a wide variety of dye and pigment
products, the dye and pigment industries typically operate successive
batch processes producing varying dye and pigment products. These batch
operations generate a wide variety of solid wastes on a periodic basis.
These wastes generally can be divided into two general types:
commingled wastes and process-specific wastes
sludge.
Due to the market demand for a wide variety of dye and pigment
products, the dye and pigment industries typically operate successive
batch processes producing varying dye and pigment products. These batch
operations generate a wide variety of solid wastes on a periodic basis.
These wastes generally can be divided into two general types:
commingled wastes and process-specific wastes. Commingled wastes are
wastes combined from multiple processes prior to management (e.g.,
wastewaters). Commingled wastes include secondary wastes generated from
the treatment of other commingled wastes (e.g., wastewater treatment
sludges). Process-specific wastes are wastes that are unique to a
specific process and may be managed independently of one another (e.g.,
spent filter aids).
On December 22, 1994, EPA published a notice that proposed listing
decisions for 11 of the wastes covered in the consent decree. EPA
deferred any listing decisions on three other wastes. (See 59 FR
66072). As a result, EPA and EDF amended the consent decree (paragraph
1h(v)) to establish deadlines for promulgating listing decisions for
two of the deferred wastes. In today's notice, EPA is proposing listing
determinations for all three of the deferred wastes.
C. Confidential Business Information (CBI) Issues Regarding This Rule
For the purpose of developing the supporting data for listing
rulemakings for the dye and pigment industry, a questionnaire was sent
out to industry pursuant to RCRA Section 3007. Some of the information
collected from industry and used in the 1994 proposed rule, as well as
today's proposed rule, was claimed as confidential. As a result of a
consent order and a subsequent preliminary injunction in connection
of developing the supporting data for listing
rulemakings for the dye and pigment industry, a questionnaire was sent
out to industry pursuant to RCRA Section 3007. Some of the information
collected from industry and used in the 1994 proposed rule, as well as
today's proposed rule, was claimed as confidential. As a result of a
consent order and a subsequent preliminary injunction in connection
with a case brought by some of the dye and pigment industry to prevent
the disclosure of information claimed as CBI, Magruder et al. v. U.S.
EPA, Civ. No. 94-5768 (D.N.J.), the EPA is enjoined from disclosing
information claimed as confidential until all CBI determinations have
been made on the data intended to be published in connection with these
proposed rules.
Therefore, as with the 1994 proposed rule, we have removed
information from this preamble and rule (and supporting background
documents), if the information may disclose information claimed as CBI.
We note the missing information in the text to this rule, where
appropriate. However, we have included data that are not claimed as
CBI, whenever such data are available. We have also included data that
we obtained from public or non-CBI sources. Wherever we are unable to
include pertinent data in a table, the following statement appears in a
footnote: ``Relevant data are not included at the present time due to
business confidentiality concerns.''
At this time EPA expects that this rule will also need some form of
notice of data availability (NODA) or reproposal prior to promulgation
as a final rule because of CBI problems. However, EPA is proceeding as
noted above to allow publication of as much of the proposed rule as can
be shared at this time. Thus, commenters can see as much as possible of
EPA's current thinking and can comment on the basic approach, the
implementation issues, and other portions of the rule that can
reasonably be commented upon, even with the current redactions
rule because of CBI problems. However, EPA is proceeding as
noted above to allow publication of as much of the proposed rule as can
be shared at this time. Thus, commenters can see as much as possible of
EPA's current thinking and can comment on the basic approach, the
implementation issues, and other portions of the rule that can
reasonably be commented upon, even with the current redactions. We
intend to supplement the public record prior to issuing a final listing
determination.
D. What Wastes Are Covered in Today's Proposed Rule?
Today's proposal applies only to the dye and pigment manufacturing
industries. The end-user markets for dyes and pigments, which include
textiles, paper, leather, ink, paints, coatings, plastics, fibers, and
other low volume markets, are not within the scope of our listing
determination. Consistent with both HSWA Amendments of 1984 and the
consent decree, EPA is only making proposed determinations on wastes
from the production and manufacturing of dyes and pigments.
In the 1994 proposed rule, the Agency deferred action on three
waste streams based on insufficient characterization data, or lack of
health-based levels for specific constituents of concern. The
``deferred'' dye and pigment waste streams are the subject of today's
proposed rule. The three deferred wastes are:
Spent filter aids, diatomaceous earth, or adsorbents used
in the production of azo, anthraquinone, or triarylmethane dyes,
pigments, or FD&C colorants.
Wastewater treatment sludge from the production of
triarylmethane dyes and pigments (excluding triarylmethane pigments
using aniline as a feedstock).
Wastewater treatment sludge from the production of
anthraquinone dyes and pigments.
This proposed rule will refer to these wastes as ``filter aids,''
``TAM sludges,'' and ``anthraquinone sludges'' respectively. Brief
descriptions of the three wastes are given below
ludge from the production of
triarylmethane dyes and pigments (excluding triarylmethane pigments
using aniline as a feedstock).
Wastewater treatment sludge from the production of
anthraquinone dyes and pigments.
This proposed rule will refer to these wastes as ``filter aids,''
``TAM sludges,'' and ``anthraquinone sludges'' respectively. Brief
descriptions of the three wastes are given below.
Filter Aids
Manufacturers add filter aids (e.g., diatomaceous earth) to some
reaction processes to remove particulate impurities. The spent filter
aids then are collected in a filter press and the press cake, sometimes
called a clarification sludge, is disposed as waste. In some cases,
facilities also use filter aids following completed reactions to
clarify and purify certain products. The Agency grouped spent filter
aids, diatomaceous earth, and adsorbents used in the production of all
relevant classes of dyes and pigments, because these wastes typically
contain unreacted raw materials, by-products, and impurities. The
constituent composition of these filter aids varies depending on the
dye or pigment produced and the raw materials used. The Agency deferred
a determination as to whether to list Filter Aids in 1994 due to
insufficient waste characterization data for this widely variable waste
(see 59 FR 66103).
TAM Sludges
As described in the 1994 proposed rule, EPA evaluated wastes from
the production of TAM pigments that use aniline as starting material
(``feedstock'') separately from other TAM wastewaters and wastewater
treatment sludges. This was because the process that uses aniline as a
feedstock is somewhat different (see 59 FR 66081 and 66096). We
proposed listing decisions for wastes from TAM pigments derived from
aniline in the 1994 notice, but deferred a decision for wastewater
treatment sludge from the production of TAM dyes and pigments that do
not use aniline
other TAM wastewaters and wastewater
treatment sludges. This was because the process that uses aniline as a
feedstock is somewhat different (see 59 FR 66081 and 66096). We
proposed listing decisions for wastes from TAM pigments derived from
aniline in the 1994 notice, but deferred a decision for wastewater
treatment sludge from the production of TAM dyes and pigments that do
not use aniline. Today's proposed rule addresses the wastewater
treatment sludges from production of TAM dyes and pigments, excluding
TAM pigments using aniline as a feedstock.
The typical wastewater treatment sludge is generated via the
treatment of the following process waste streams: equipment washdown,
plant run-off, spent scrubber liquid and mother liquor. Wastewater
treatment steps usually include: neutralization to adjust pH,
clarification, and biological treatment. Pretreatment sludges may be
generated from precipitation/filtration in neutralization tanks, and
from treatment with adsorbents, such as activated carbon. Biological
treatment can also lead to generation of a wastewater treatment sludge.
Sludge streams are further processed, typically through filtration and
dewatering, prior to disposal. Information related to the management of
TAM sludges is not included due to business confidentiality concerns.
In support of the 1994 proposed rule, we attempted to sample TAM
sludges (from production of TAM pigments that do not use aniline as a
feedstock). However, TAM dyes or pigments were not being produced at
the time EPA collected its samples, and we could not attribute any
constituents detected to TAM production. Thus, EPA deferred any listing
decision for sludges from the production of TAM dyes and pigments
(excluding TAM pigments using aniline as a feedstock) due to
insufficient waste characterization data (see 59 FR 66095).
Anthraquinone Sludges
The typical anthraquinone sludge is generated via the treatment of
process wastewater similar to that described for TAM sludges
detected to TAM production. Thus, EPA deferred any listing
decision for sludges from the production of TAM dyes and pigments
(excluding TAM pigments using aniline as a feedstock) due to
insufficient waste characterization data (see 59 FR 66095).
Anthraquinone Sludges
The typical anthraquinone sludge is generated via the treatment of
process wastewater similar to that described for TAM sludges. From the
data collected for the 1994 proposed rule, the only constituents
detected in the waste that we could attribute to anthraquinone
production did not have health-based benchmarks. EPA was unable to
identify any appropriate surrogate compound of known toxicity to
estimate the toxicity of these constituents. Because of the lack of
health-based benchmarks or reliable surrogates, we deferred any listing
determination in the 1994 proposal. As part of the deferral, we
requested toxicity data or any suitable surrogates for the two waste
constituents (see 59 FR 66101).
E. What Information Did EPA Collect and Use?
1. The RCRA Section 3007 Survey
In support of the 1994 proposed rule, EPA distributed a detailed
RCRA section 3007 survey to dye and pigment manufacturing facilities in
1992. The purpose of the questionnaire was to collect information on
the 12 specific residuals identified in the 1991 consent decree. Most
questions in this survey requested information on waste generation and
management activities in
RA Section 3007 Survey
In support of the 1994 proposed rule, EPA distributed a detailed
RCRA section 3007 survey to dye and pigment manufacturing facilities in
1992. The purpose of the questionnaire was to collect information on
the 12 specific residuals identified in the 1991 consent decree. Most
questions in this survey requested information on waste generation and
management activities in
1991. From data provided by questionnaire respondents, EPA identified
facilities that manufacture azo, anthraquinone, or triarylmethane dyes
or pigments (the number of facilities is not included due to business
confidentiality concerns). In the questionnaire, EPA collected
information regarding the products manufactured at each facility, raw
materials and additives used, and 1991 production volumes. The
questionnaire also collected information on the management of the
wastes generated by each facility, including waste quantity and how the
wastes were managed and disposed.
EPA contacted companies generating the three deferred wastes at
issue in today's proposed rule to update the information in the 1992
Sec. 3007 survey. The updated information EPA collected includes the
quantities of wastes generated (for the year 1997), and the waste
management practices used by the facilities for each of the wastes. The
Agency used this updated information in its risk assessment, as
described in Section III.D. The following discussion summarizes the
information collected for each waste.
Filter Aids
In response to the 1992 questionnaire, a number of dye and pigment
manufacturers reported generating filter aid wastes. We are not
including information on the number of facilities generating this
waste, nor the waste quantities reported for 1991, due to business
confidentiality concerns. We also cannot include information collected
by EPA in 1998 on the number of generators and the quantities for 1997
for the same reason
nnaire, a number of dye and pigment
manufacturers reported generating filter aid wastes. We are not
including information on the number of facilities generating this
waste, nor the waste quantities reported for 1991, due to business
confidentiality concerns. We also cannot include information collected
by EPA in 1998 on the number of generators and the quantities for 1997
for the same reason. Facilities that generated spent filter aids may
generate this waste from the production of a wide variety of different
dyes and pigments. For example, one facility reported generating a
total of 90 Mtons of filter aid wastes in 1997, comprised of 18 filter
aids arising from the production of dyes and/or pigments.
TAM Sludges
In response to the 1992 questionnaire, a number of dye and pigment
manufacturers reported generating TAM wastewater treatment sludges. We
are not including information on the number of facilities generating
this waste, nor the waste quantities reported for 1991, due to business
confidentiality concerns. We also cannot include information collected
by EPA in 1998 on the number of generators and the quantities for 1997
for the same reason. As noted previously, EPA was unable to collect
samples of this waste.
Anthraquinone Sludges
In response to the 1992 questionnaire, a number of dye and pigment
manufacturers reported generating anthraquinone wastewater treatment
sludges. We are not including information on the number of facilities
generating this waste, nor the waste quantities reported for 1991, due
to business confidentiality concerns. We also cannot include
information collected by EPA in 1998 on the number of generators and
the quantities for 1997 for the same reason.
As noted above, the only chemicals detected in sludge that could be
attributed to anthraquinone production in 1994 did not have health-
based benchmarks. EPA did not receive any information in comments on
the 1994 proposal that would assist us in calculating health
benchmarks
ude
information collected by EPA in 1998 on the number of generators and
the quantities for 1997 for the same reason.
As noted above, the only chemicals detected in sludge that could be
attributed to anthraquinone production in 1994 did not have health-
based benchmarks. EPA did not receive any information in comments on
the 1994 proposal that would assist us in calculating health
benchmarks. Furthermore, EPA has not subsequently found any suitable
surrogates to estimate the toxicity of the compounds in question.
2. Sampling and Analysis Data
For the 1994 proposed rule, the Agency performed sampling to
characterize the wastes generated at dye and pigment manufacturing
facilities. EPA collected a total of 34 waste samples from facilities
to characterize the residuals under evaluation. The analytical results
for all the wastes are summarized in the Background Document for
Identification and Listing of the Deferred Dye and Pigment Wastes,
Appendix A (hereafter called the Listing Background Document) for
today's proposal, which is available in the docket. (Note however, that
we cannot release much of the analytical data due to business
confidentiality concerns). The dye and pigment manufacturers also
provided a limited amount of additional waste sampling and analysis
data in 1994. These additional data include aggregated analytical
results from 19 industry analyses of samples that EPA and the
facilities split during sampling visits. An industry trade group (Color
Pigment Manufacturers' Association, or CPMA) aggregated this analytical
information and submitted this information to EPA in April 1994. CPMA
also included this information in the group's public comments on the
1994 proposed rule (see Docket No. F-94-DPLP-FFFFF, item DPLP-0025). We
used the available sampling data from these sources to identify
potential constituents of concern for use in today's proposed rule.
For the 1994 proposed rule, EPA collected limited sampling data for
spent filter aids
ormation to EPA in April 1994. CPMA
also included this information in the group's public comments on the
1994 proposed rule (see Docket No. F-94-DPLP-FFFFF, item DPLP-0025). We
used the available sampling data from these sources to identify
potential constituents of concern for use in today's proposed rule.
For the 1994 proposed rule, EPA collected limited sampling data for
spent filter aids. Our sampling results were inconclusive for TAM
sludges because these products were not manufactured during our
sampling visit. While we did succeed in obtaining samples of
anthraquinone sludge, we do not have health benchmarks for the two
constituents that could be attributed to production of anthraquinone
products.
III. Approach Used in This Proposed Listing
A. Summary of Today's Action
In listings promulgated by EPA, we typically describe the scope of
the listing in terms of the waste material and the industry or process
generating the waste. However, in today's rule we are proposing to use
a new approach in these listings, a ``concentration-based listing.'' In
a concentration-based listing, a waste would be hazardous unless a
determination is made that it does not contain any of the constituents
of concern at or above specified levels of concern. This approach draws
from the concept of the characteristic approach to defining a hazardous
waste, in that whether a waste is hazardous depends on the levels of
key constituents in the wastes. We describe this concept in detail
later in this notice.
We are proposing concentration-based listings for two of the
deferred wastes:
Spent filter aids, diatomaceous earth, or adsorbents used
in the production of azo, anthraquinone, or triarylmethane dyes,
pigments, or FD&C colorants.
Wastewater treatment sludge from the production of
triarylmethane dyes and pigments (excluding triarylmethane pigments
using aniline as a feedstock)
this notice.
We are proposing concentration-based listings for two of the
deferred wastes:
Spent filter aids, diatomaceous earth, or adsorbents used
in the production of azo, anthraquinone, or triarylmethane dyes,
pigments, or FD&C colorants.
Wastewater treatment sludge from the production of
triarylmethane dyes and pigments (excluding triarylmethane pigments
using aniline as a feedstock).
For both wastes, the listings would apply if the wastes contain any
of the constituents identified in the regulation at a concentration
equal to or greater than the hazardous level set for that constituent
(see tables IV-1 and IV-2 for levels). We are also proposing a set of
conditions and requirements that must be met if a facility wishes to
claim its waste does not exceed these levels and is, therefore, not
covered by the listing.
We are proposing not to list as hazardous the third waste
considered:
Wastewater treatment sludge from the production of
anthraquinone dyes and pigments.
In the following sections we describe the concept of a
concentration-based listing and the risk assessment methodology we used
to develop concentration limits for each wastes. We describe our
proposed decisions in more detail in Section IV.
B. What Is a Concentration-Based Listing?
A concentration-based listing specifies constituent-specific levels
in a waste that causes the waste to become a listed hazardous waste. In
this proposed rule, we identify constituents of concern likely to be
present in two categories of dye and pigment wastes. Using risk
assessment tools developed to support our hazardous waste
identification program, we assessed the potential risks associated with
the constituents of concern. From this analysis, we developed ``listing
concentrations'' for each of the constituents of concern in the two
waste categories
entify constituents of concern likely to be
present in two categories of dye and pigment wastes. Using risk
assessment tools developed to support our hazardous waste
identification program, we assessed the potential risks associated with
the constituents of concern. From this analysis, we developed ``listing
concentrations'' for each of the constituents of concern in the two
waste categories.
If you generate any of the wastes included in the two categories of
dye and pigment wastes referenced above, you must either determine
whether or not your waste is hazardous or assume that it is hazardous
as-generated. We are proposing that you determine representative
concentrations for the constituents of concern in your waste through
sampling and analyses, unless you can use process knowledge to
demonstrate that certain constituents are not present in your waste.
Based on this information, you must make a determination as to whether
or not your waste is a listed hazardous waste. Your waste would be a
listed hazardous waste if it contains any of the constituents of
concern at a concentration equal to or greater than the hazardous
concentration identified for that constituent. If all of the
constituents of concern in your waste were below their respective
listing concentrations, you would need to notify EPA that your wastes
are nonhazardous. The detailed descriptions of the steps you would be
required to follow to implement the concentration-based listing are
described later in this proposed rule.
C. Why Is a Concentration-Based Approach Being Used for This Listing?
all of the
constituents of concern in your waste were below their respective
listing concentrations, you would need to notify EPA that your wastes
are nonhazardous. The detailed descriptions of the steps you would be
required to follow to implement the concentration-based listing are
described later in this proposed rule.
C. Why Is a Concentration-Based Approach Being Used for This Listing?
There are several reasons for using a concentration-based approach
for listing the deferred dyes and pigments wastes. First, these wastes
are generated by an industry that uses batch processes to manufacture a
variety of products, in response to market demand for a wide variety of
dye and pigment products. Batch operations may result in highly
variable wastes at the same facility or different facilities. A
concentration-based approach allows the variable wastes generated at
these facilities to be evaluated individually for hazard, so only the
truly hazardous wastes are listed. This tailored approach is more cost-
effective for the industry than a standard listing, and avoids the
unnecessary regulation of nonhazardous waste.
Alternatively, EPA could have attempted to collect more information
on these specific wastes to support a straightforward listing, i.e.,
without any concentration limits. However, such a data collection
effort would have been difficult due to the wide variety of individual
dye or pigment products produced and the potential variability in the
waste characteristics. For example, one facility generated 18 filter
aid wastes in 1997 arising from the production of different dyes and/or
pigments. Gathering sufficient samples to evaluate all potential filter
aid wastes would require a large commitment of scarce Agency resources
that would have been beyond the reasonable scope of this rulemaking,
especially given the time constraints of the existing Consent Decree
example, one facility generated 18 filter
aid wastes in 1997 arising from the production of different dyes and/or
pigments. Gathering sufficient samples to evaluate all potential filter
aid wastes would require a large commitment of scarce Agency resources
that would have been beyond the reasonable scope of this rulemaking,
especially given the time constraints of the existing Consent Decree.
Given the relatively low quantities of the individual filter aids
produced, EPA does not feel such an effort was justified.
Second, many manufacturers in the dye and pigment industries want
to keep facility-specific product and waste information confidential.
These manufacturers are concerned that release of such information
could cause competitive harm. A concentration-based listing allows us
to rely less on CBI, since we do not use this information directly to
set the listing concentrations. This means we don't use specific
information, such as product formulations or concentrations of
constituents in the wastes, to set hazardous concentration levels for
constituents of concern. As noted earlier, however, in this particular
listing EPA still must resolve the CBI claims on some specific data
prior to release.
Finally, a concentration-based listing approach may provide an
incentive for hazardous waste generating facilities to modify their
manufacturing processes or treat their wastes. For example, if a
facility has a listed hazardous waste based on constituent-specific
concentration levels established by EPA, it also knows the required
concentrations levels of constituents in its waste below which its
waste would become nonhazardous. Therefore, the facility may decide to
modify its manufacturing process in order to generate a nonhazardous
waste. Thus, this approach encourages waste minimization
lity has a listed hazardous waste based on constituent-specific
concentration levels established by EPA, it also knows the required
concentrations levels of constituents in its waste below which its
waste would become nonhazardous. Therefore, the facility may decide to
modify its manufacturing process in order to generate a nonhazardous
waste. Thus, this approach encourages waste minimization.
Section 1003 of the HSWA indicates that one of RCRA's goals is to
promote protection of human health and the environment and to conserve
valuable material and energy resources by ``minimizing the generation
of hazardous waste and the land disposal of hazardous waste by
encouraging process substitution, materials recovery, properly
conducted recycling, and reuse and treatment.'' Section 1003 further
provides that it is a national policy of the United States that,
whenever feasible, the generation of hazardous waste is to be reduced
or eliminated as expeditiously as possible.
The Pollution Prevention Act of 1990 (42 U.S.C. 13101 et seq., Pub.
L. 101-508, November 5, 1990) provides a hierarchy of pollution
prevention approaches. Pollution should be prevented or reduced;
pollution that cannot be prevented should be recycled or reused in an
environmentally safe manner; pollution that cannot be prevented/reduced
or recycled should be treated; and disposal or release into the
environment should be chosen only as a last resort. A concentration-
based listing may prevent pollution by discouraging generation of
wastes with high levels of toxic constituents. If EPA provides a
concentration-based target in the listing, generators would have the
regulatory and economic incentive to meet the reduced levels.
D. What Risk Assessment Approach Did EPA Use?
r release into the
environment should be chosen only as a last resort. A concentration-
based listing may prevent pollution by discouraging generation of
wastes with high levels of toxic constituents. If EPA provides a
concentration-based target in the listing, generators would have the
regulatory and economic incentive to meet the reduced levels.
D. What Risk Assessment Approach Did EPA Use?
Under a concentration-based listing approach, EPA must calculate
concentration levels, or ``listing levels,'' in the waste that would
present a hazard. To accomplish this, the Agency: (1) Selected
constituents of potential concern in the waste, (2) chose a plausible
waste management scenario, (3) calculated exposure concentrations by
modeling the release and transport of the constituents from the waste
management unit to the point of exposure, and (4) calculated waste
concentrations that would yield the target risk level at the point of
exposure.
The following sections present an overview of the analysis EPA used
to calculate risk-based listing levels for filter aids and TAM sludges
generated during the manufacture of organic dye and pigment products.
You will find more details of how we selected the constituents of
concern in the Listing Background Document. Details of the risk
assessment are provided in the document in the docket entitled
Development of Risk-Based Listing Concentrations for Hazardous
Constituents Contained in Spent Filter Aids and Triarylmethane (TAM)
Wastewater Treatment Sludges (hereafter called the Risk Assessment
Background Document).
details of how we selected the constituents of
concern in the Listing Background Document. Details of the risk
assessment are provided in the document in the docket entitled
Development of Risk-Based Listing Concentrations for Hazardous
Constituents Contained in Spent Filter Aids and Triarylmethane (TAM)
Wastewater Treatment Sludges (hereafter called the Risk Assessment
Background Document).
1. Choosing the Constituents of Concern
Our initial universe of constituents of potential concern included
any constituent detected in any wastestream from the production of all
classes of dyes and pigments we examined (i.e., all wastes sampled
associated with the production of azo, TAM, and anthraquinone dyes or
pigments, including FD& C colorants). We typically obtain samples from
the specific wastes of concern for a standard listing evaluation.
However, obtaining representative samples of filter aids and TAM
sludges was difficult, as noted in the 1994 proposal (see 59 FR 66095
and 66103), due to widely varying wastes and batch processes. We
believe that the broad universe of constituents detected in all wastes
examined provides an appropriate starting point for selecting
constituents of concern for filter aids, because these wastes may be
generated from the production of many kinds of dyes and pigments.
Because TAM sludge is a much more narrowly defined waste, we relied on
available information regarding constituents used in TAM production to
determine what constituents we expect in the waste.
Our primary source of potential constituents was the set of
analytical data EPA collected to support the 1994 proposed rule
described in Section I.E.2 of today's notice. We also examined the
limited analytical data from industry to confirm the presence of
constituents. These data sets included sampling results for all wastes
under consideration in the 1994 proposal, because the available
analytical data for the three specific wastes at issue are limited
alytical data EPA collected to support the 1994 proposed rule
described in Section I.E.2 of today's notice. We also examined the
limited analytical data from industry to confirm the presence of
constituents. These data sets included sampling results for all wastes
under consideration in the 1994 proposal, because the available
analytical data for the three specific wastes at issue are limited. For
filter aids, EPA obtained some samples in support of the 1994 proposed
rule. However, filter aids may potentially contain a variety of
constituents, depending on what products and processes are in use by
different facilities. Therefore, the limited waste analysis data for
filter aids alone were not adequate to establish constituents of
concern. We have no waste analysis data that would allow us to identify
specific constituents of concern for TAM or anthraquinone sludges. As
noted in Section II.D, our sampling results were inconclusive for TAM
sludges because TAM dyes or pigments were not being produced at the
time EPA collected its samples. While we did succeed in obtaining
samples of anthraquinone sludge, we do not have health benchmarks for
the two constituents that could be attributed to production of
anthraquinone products. Thus, we did not pursue a listing for this
waste.
We used the analytical data from all wastes to develop an initial
list of potential chemicals of concern. We then reduced and augmented
this list based on several factors. First, we can only develop a
concentration level if a health benchmark exists for the chemical.
Therefore, we removed constituents without health benchmarks from
further evaluation. The sources we used for health benchmark data are
summarized below; the Risk Assessment Background Document contains
further information (see Appendix E).
Due to the lack of health-based benchmarks, we excluded certain
constituents from consideration in today's proposed rule that we
previously evaluated for azo dye and pigment wastes in the 1994
proposed rule
hmarks from
further evaluation. The sources we used for health benchmark data are
summarized below; the Risk Assessment Background Document contains
further information (see Appendix E).
Due to the lack of health-based benchmarks, we excluded certain
constituents from consideration in today's proposed rule that we
previously evaluated for azo dye and pigment wastes in the 1994
proposed rule. These constituents are acetoacetanilide (AAA),
acetoacet-o-toluidine (AAOT), and acetoacet-o-anisidine (AAOA). For the
1994 proposal, we derived health based numbers based on a Structural
Activity Relationship (SAR) analysis. The Agency has since reevaluated
and revised the SAR analysis based on comments received in response to
the 1994 proposal. The revised analysis, which has been independently
peer reviewed, concludes that the current available data are
insufficient to make a quantitative estimation of the carcinogenic
potential of these compounds, or to establish provisional non-cancer
benchmarks. The revised toxicological analysis for these compounds and
the peer review documents are provided in Appendix A to the Risk
Assessment Background Document.
We then screened the remaining potential constituents to remove
chemicals that we believed were of little use in defining the hazardous
characteristic of the two wastes at issue. In this screen we considered
the prevalence with which a constituent is used in the manufacturing of
the different classes of dyes and pigments at issue in the consent
decree, the likelihood that a chemical could be attributed to such
production, and the frequency with which a chemical was detected in
wastes samples. In considering if the constituents detected are likely
to be derived from dye or pigment production, we used publicly
available information from the Colour Index International (3rd edition,
1996)
es of dyes and pigments at issue in the consent
decree, the likelihood that a chemical could be attributed to such
production, and the frequency with which a chemical was detected in
wastes samples. In considering if the constituents detected are likely
to be derived from dye or pigment production, we used publicly
available information from the Colour Index International (3rd edition,
1996). For example, we retained any chemicals that were detected that
are commonly used as raw materials in the production of the dyes and
pigments at issue (e.g., aniline is widely used in the production of
azo products; see Colour Index, vol. 4, pages 4009 and 4699). We also
kept some chemicals detected that have no apparent use as raw
materials, because they may be impurities or degradation products from
chemicals used in the manufacturing process (e.g., naphthalene may be
an impurity in a commonly used raw material, beta-naphthol). We removed
some constituents, such as acetone and methylene chloride, that were
detected frequently in samples, because they are common laboratory
contaminants and/or common solvents that have no reported use in the
production of these dyes and pigments. While such constituents may be
present in wastes, we did not consider them further because we could
not reasonably attribute them to dye and pigment production processes
sampled. We dropped other constituents that had little or no reported
use in the Colour Index; the dropped constituents were also rarely
found in waste samples.
We are proposing to include the selected core chemicals in Table
III-1 as constituents of concern for defining the two listed wastes.
This table summarizes the frequency with which we detected the
chemicals in waste samples, and prevalence of use of the chemicals in
the production of the three dye and pigment classes (azo, TAM, and
anthraquinone) as found in the Colour Index
n waste samples.
We are proposing to include the selected core chemicals in Table
III-1 as constituents of concern for defining the two listed wastes.
This table summarizes the frequency with which we detected the
chemicals in waste samples, and prevalence of use of the chemicals in
the production of the three dye and pigment classes (azo, TAM, and
anthraquinone) as found in the Colour Index. For filter aids we
included constituents on the final list of constituents of concern if
we detected the chemicals with at least a low frequency (i.e, in more
than one sample), and we found some evidence that industry used the
chemicals in the production of the dyes and pigments at issue. We also
selected several chemicals that we believe may be degradation products
of other raw materials (e.g., p-phenylenediamine), or possible
impurities in other starting materials (e.g., naphthalene). Finally, we
included several compounds that may arise from TAM production, as
described below, even though we do not have analytical data showing
these chemicals are present in wastes from this industry. (More details
of our rationale for choosing chemicals of concern are given in the
Listing Background Document, Section 4).
We chose to add two chemicals for consideration as constituents of
concern that were reported to be used in the production of TAM
products, even though we did not find them in any waste samples. In the
case of benzaldehyde, we did not analyze any of the wastes for this
compound. However, this chemical is reported to be used in the
production of TAM products (see Colour Index, vol.4, page 4727). We
analyzed for the other chemical (the
tion as constituents of
concern that were reported to be used in the production of TAM
products, even though we did not find them in any waste samples. In the
case of benzaldehyde, we did not analyze any of the wastes for this
compound. However, this chemical is reported to be used in the
production of TAM products (see Colour Index, vol.4, page 4727). We
analyzed for the other chemical (the
identity is not given due to business confidentiality concerns), but we
did not find it in any samples. However, the 3007 Survey indicated
significant use of this chemical in the production of TAM dyes. EPA did
not succeed in obtaining waste samples during the production of TAM dye
and pigments (excluding TAM pigments using aniline as a feedstock).
Therefore, based on the known uses in TAM manufacturing, we considered
these two chemicals as potential constituents of concern.
In the case of TAM sludges, we considered proposing the same list
of core constituents used for filter aids. We considered this option
primarily because we have no analytical data that reflects wastes
arising from TAM production. (We do have data for wastes from the
production of TAM pigments using aniline as a feedstock; this subset of
TAM wastes were dealt with in the 1994 proposed rule and is not at
issue in today's notice. We decided to propose a list based on the
constituents that are known to be used in the manufacturing of TAM dyes
or pigments. Using public sources of information (i.e., Colour Index),
we were able to identify reactants reported in use for TAM products.
Except as noted previously, the constituents identified in this way are
consistent with the constituents reported in the 3007 Survey. This
analysis led to the list of constituents of concern for TAM sludges.
The publicly available information we used was consistent with the
information provided by industry in responses to the 3007 Survey,
except in a few cases
ported in use for TAM products.
Except as noted previously, the constituents identified in this way are
consistent with the constituents reported in the 3007 Survey. This
analysis led to the list of constituents of concern for TAM sludges.
The publicly available information we used was consistent with the
information provided by industry in responses to the 3007 Survey,
except in a few cases. In some instances (the identities are not given
due to business confidentiality concerns), the Colour Index showed low
to moderate use of the chemicals that was not confirmed in the 3007
Survey. Conversely, in the case of another chemical (the identity is
not given due to business confidentiality concerns), the 3007 Survey
indicated significant use in the production of TAM dyes, while the
Colour Index did not. In cases where we had these discrepancies, we
relied on the source that showed use and assumed that these chemicals
may be used in production.
In choosing core constituents of concern for a concentration-based
listing for filter aids and TAM sludges, we considered adding other
constituents shown in Table III-2. We considered these chemicals
because they were detected with a moderate frequency, they had some use
in manufacturing the dye and pigment products of concern, or they are
in a class of compounds that have been historically linked to dye
production (benzidines). However, we believe that these constituents
are unlikely to be present in these two specific wastes at levels of
concern. Some of the chemicals in Table III-2 could not be linked to
the production of the dye and pigment classes at issue
manufacturing the dye and pigment products of concern, or they are
in a class of compounds that have been historically linked to dye
production (benzidines). However, we believe that these constituents
are unlikely to be present in these two specific wastes at levels of
concern. Some of the chemicals in Table III-2 could not be linked to
the production of the dye and pigment classes at issue. We did not
include chemicals in the final list of core constituents of concern
unless we could find some evidence that the presence of a chemical was
related to the production of the classes of the dyes and pigments of
interest (for filter aids, the production of azo, TAM, or anthraquinone
products; for TAM sludges, the production of TAM products, excluding
TAM pigments using aniline as a feedstock). This is because many waste
samples were wastewaters or sludges collected from combined wastewater
treatment systems, and such systems typically receive waste streams
from various other production processes at facilities. We did not
include other chemicals because they were never or rarely detected in
EPA's analysis.
Table III-1.--Core Constituents of Concern in Filter Aids and TAM Sludges
--------------------------------------------------------------------------------------------------------------------------------------------------------
Core constituents
of concern for
Constituent filter aids (FA) Frequency of detection\1\ Use in production of dye Comments
and/or TAM sludges and pigment classes\2\
(T)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Aniline............................ FA High; S............................... High use (Azo); some use ..........................
in TAM pigment (aniline
based)
Benzaldehyde....................... FA, T Not analyzed.......................... Moderate use in TAM Not analyzed, but common
products**. reactant in TAM
production
----------------------------------------------------------------------
Aniline............................ FA High; S............................... High use (Azo); some use ..........................
in TAM pigment (aniline
based)
Benzaldehyde....................... FA, T Not analyzed.......................... Moderate use in TAM Not analyzed, but common
products**. reactant in TAM
production.
Chloroaniline, p-.................. FA Moderate, S........................... Rare use (Azo)............ Aromatic amine; possible
contaminant.
Cresol, p-......................... FA Moderate, S........................... Low use (Azo) found in Industry split samples did
Colour Index;**. not distinguish meta and
para isomers.
Dimethoxybenzidine, 3,3'-.......... FA Low, S................................ Moderate use (Azo) ..........................
Dimethylaniline, N,N-.............. FA, T Rare.................................. Moderate to high use found Rarely detected, but TAM
for TAM dye production; waste not sampled and
rare use otherwise. common reactant in TAM
production.
Diphenylamine...................... FA, T Moderate.............................. Low use (Azo); rare use in Indistinguishable from N-
TAMs. Nitrosodiphenylamine by
EPA method (GC/MS).
Diphenylhydrazine, 1,2-............ FA Moderate.............................. None reported............. Possible oxidation product
of aniline;
indistinguishable from
azobenzene by EPA method
(GC/MS).
Formaldehyde....................... FA, T Moderate, S........................... Moderate use for TAM; low ..........................
use for others
Naphthalene........................ FA Moderate/High......................... None reported............. Possible impurity in
common Azo raw material
(beta-naphthol).
Phenol............................. FA Moderate/High, S...................... Moderate use (Azo)........ ..........................
Phenylenediamine, p-(4- FA Low/Moderate.......................... Moderate use (Azo).......
others
Naphthalene........................ FA Moderate/High......................... None reported............. Possible impurity in
common Azo raw material
(beta-naphthol).
Phenol............................. FA Moderate/High, S...................... Moderate use (Azo)........ ..........................
Phenylenediamine, p-(4- FA Low/Moderate.......................... Moderate use (Azo)........ Possible hydrolysis
aminoaniline). product of other azo raw
materials
(aminoacetoacetanilide);
indistinguishable from o-
isomer in EPA analysis.
Toluidine, o-(2-aminotoluene)...... FA, T Moderate, S........................... Moderate use (Azo); low Hydrolysis product of raw
use (TAM). materials (AAOT); EPA
could not separate o-and
p-isomers during
analysis.
Toluidine, p-(4-aminotoluene)...... FA, T Moderate, S........................... Low to moderate uses (TAM EPA could not separate o-
and anthraquinone). and p-isomers during
analysis.
(**)
(**)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ As found in EPA analysis of samples of all dye and pigment wastes from production of azo, TAM, and anthraquinone dyes/pigments and FD& C colorants;
``ND'' means not detected; ``S'' denotes reported in industry split samples.
\2\ From the Colour Index International, 3rd edition, 1996.
**Relevant data are not included at the present time for a number of constituents due to business confidentiality concerns.
in EPA analysis of samples of all dye and pigment wastes from production of azo, TAM, and anthraquinone dyes/pigments and FD& C colorants;
``ND'' means not detected; ``S'' denotes reported in industry split samples.
\2\ From the Colour Index International, 3rd edition, 1996.
**Relevant data are not included at the present time for a number of constituents due to business confidentiality concerns.
Table III-2.--Other Constituents of Possible Concern
----------------------------------------------------------------------------------------------------------------
Use in
production of
Constituent Frequency of detection \1\ dye and pigment Comments
classes \2\
----------------------------------------------------------------------------------------------------------------
Benzene...................... Moderate, S..................... None reported.. Found in waste, but no use;
common contaminant from many
industrial processes.
Benzidine.................... Low............................. No reported use Used historically (Azo), but
domestically. no current domestic use
reported; only found in
wastes from processes that do
not use filter aids.
Chlorobenzene................ Moderate, S..................... None reported.. No known use; other uses as
solvent.
Chloroform................... Moderate, S..................... None reported.. No use; contaminant from
treated water supplies; other
uses as solvent.
Dichlorobenzene, 1,2-........ Moderate........................ None reported.. No use in azo/TAM/
anthraquinone production;
solvent uses in other dye
production (Oxazine dyes).\2\
Phenylenediamine, o-(2- (See comments).................. Low use EPA found analytical methods
aminoaniline). (anthraquinone unreliable (very poor
). recoveries); may be
indistinguishable from p-
isomer.
Toluidine, 5-nitro-o-(2- ND, S........................... Moderate use Not detected in any EPA
methyl-5-nitroaniline). (Azo). samples of azo wastes and
reported in only 1 industry
sample
\2\
Phenylenediamine, o-(2- (See comments).................. Low use EPA found analytical methods
aminoaniline). (anthraquinone unreliable (very poor
). recoveries); may be
indistinguishable from p-
isomer.
Toluidine, 5-nitro-o-(2- ND, S........................... Moderate use Not detected in any EPA
methyl-5-nitroaniline). (Azo). samples of azo wastes and
reported in only 1 industry
sample.
(**)
----------------------------------------------------------------------------------------------------------------
\1\ As found in EPA analysis of samples of all dye and pigment wastes from production of azo, TAM, and
anthraquinone dyes/pigments and FD& C colorants; ``ND'' means not detected; ``S'' denotes reported in industry
split samples.
\2\ From the Colour Index International, 3rd edition, 1996.
** Relevant data are not included at the present time for a number of constituents due to business
confidentiality concerns.
We believe that using analytical data from all dye and pigment
wastes sampled is clearly appropriate for filter aids. This is because
filter aids are used to treat and purify a wide variety of wastes
derived from all of the classes of dye and pigment products (azo,
triarylmethane, and anthraquinone). The shorter list for TAM sludges
also is appropriate, due to the more limited set of potential waste
constituents for this single dye and pigment class. We calculated
concentration limits for all constituents in Tables III-1 and III-2 for
both spent filter aids and TAM sludges, as we describe later in this
notice.
We are seeking comment on whether the constituents of concern we
selected are appropriate for the concentration-based listings for the
two wastes under consideration. We are interested in any information on
the potential for these, or any other constituents in Table III-2, to
be in these wastes at levels of concern. We believe that it is
reasonable to select constituents that we can link to the dye and
pigment processes under evaluation
ents of concern we
selected are appropriate for the concentration-based listings for the
two wastes under consideration. We are interested in any information on
the potential for these, or any other constituents in Table III-2, to
be in these wastes at levels of concern. We believe that it is
reasonable to select constituents that we can link to the dye and
pigment processes under evaluation. To require testing for an extensive
list of constituents without adequate reason would lead to unnecessary
analysis by industry in evaluating if their wastes meet the listing
levels. After considering information provided in comments on today's
proposed rule, we may choose to add potential constituents from Table
III-2, or delete proposed constituents for the two wastes.
Analytical Issues
We found problems in our chemical analysis of dye and pigment waste
samples for some of the constituents in Table III-1. In a few cases,
our analyses could not distinguish between two compounds when we used
the usual EPA methods for semivolatile organic chemicals, GC/MS method
8270 in Test Methods for Evaluating Solid Wastes, Physical/Chemical
Methods; SW-846, hereafter called SW-846). We found problems for four
pairs of compounds: diphenylamine/N-nitrosodiphenylamine; 1,2-
diphenylhydrazine/azobenzene; o-toluidine/p-toluidine; and o-
phenylenediamine/p-phenylenediamine. We propose to deal with these
problems as outlined below.
N-Nitrosodiphenylamine breaks down to diphenylamine in the method
we used; therefore these two chemicals could not be distinguished. This
means
46). We found problems for four
pairs of compounds: diphenylamine/N-nitrosodiphenylamine; 1,2-
diphenylhydrazine/azobenzene; o-toluidine/p-toluidine; and o-
phenylenediamine/p-phenylenediamine. We propose to deal with these
problems as outlined below.
N-Nitrosodiphenylamine breaks down to diphenylamine in the method
we used; therefore these two chemicals could not be distinguished. This
means
that detection by this method could be due to either compound being in
the waste. We found no reported use of the N-nitroso-derivative, but we
did find diphenylamine has some use in the production of azo and TAM
products. Therefore, for this pair we selected diphenylamine as the
likely constituent of concern. This means that, if we finalize
diphenylamine as a constituent in the concentration based listings,
generators would analyze for this constituent and assume any
concentration measured is diphenylamine.
Similarly, we could not distinguish the compounds 1,2-
diphenylhydrazine and azobenzene in the analytical method used, because
these chemicals interconvert readily under analytical conditions. Thus,
our data showed that one or both of these compounds were present in
waste samples, but we could not tell which one. In this case, we did
not find any reported use of either chemical in dye or pigment
production processes. However we believe that the presence of either
may be explained by oxidation of aniline from processes that use
aniline as a reactant. Thus, in this case we are proposing to include
the constituent with the lower concentration level (1,2-
diphenylhydrazine) to be protective. This means that generators would
analyze their waste for the total level of 1,2-diphenylhydrazine/
azobenzene, and assume that the amount detected is due only to the more
toxic 1,2-diphenylhydrazine. This is also reasonable because these
compounds may readily interconvert in wastes or the environment, thus
it is prudent to set the listing level for the more toxic component
e) to be protective. This means that generators would
analyze their waste for the total level of 1,2-diphenylhydrazine/
azobenzene, and assume that the amount detected is due only to the more
toxic 1,2-diphenylhydrazine. This is also reasonable because these
compounds may readily interconvert in wastes or the environment, thus
it is prudent to set the listing level for the more toxic component.
In our analysis we also could not separate two isomers of toluidine
(o-toluidine and p-toluidine) and phenylenediamine (o-phenylenediamine
and p-phenylenediamine). While it may be possible to distinguish these
isomers using other analytical methods, we have no data at this time to
indicate this. For the toluidine isomers, we are proposing to include
both isomers as constituents of concern. If generators cannot separate
these isomers, they could determine a total quantity for both. In the
absence of information on which isomer is expected in the waste,
generators would assume that the measured concentration is due to the
more toxic o-toluidine. Generators could use their knowledge of their
production processes, however, to definitively rule out the presence of
one of the isomers, and in this way identify which isomer is present.
For example, if generators know that only one isomer is used in any of
the relevant processes, they could document this and claim this as part
of their determination. Note that the risk-based concentration levels
we propose to set for these two chemicals are similar (i.e, they differ
by less than a factor of two for both wastes), thus the practical
distinction between these isomers is relatively unimportant, unless
generators measure them at levels approaching the listing levels.
For the o- and p-phenylenediamine isomers, we reviewed the
analytical data and now believe that o-phenylenediamine cannot be
reliably measured. We found that we could not reliably recover the
chemical from samples with known concentrations (spiked samples)
cal
distinction between these isomers is relatively unimportant, unless
generators measure them at levels approaching the listing levels.
For the o- and p-phenylenediamine isomers, we reviewed the
analytical data and now believe that o-phenylenediamine cannot be
reliably measured. We found that we could not reliably recover the
chemical from samples with known concentrations (spiked samples). In
addition, the reported usage of o-phenylenediamine in the production of
dyes and pigments is relatively limited compared to the use of p-
phenylenediamine (see Colour Index, vol. 4, page 4822). Furthermore, p-
phenylenediamine may also form from the degradation of a widely used
azo precursor, p-aminoacetoacetanilide. Therefore, because of these
analytical problems, and also because its use in dye or pigment
production is limited, we are proposing not to include o-
phenylenediamine in the list of constituents of concern for either
waste. Thus, if we finalize phenylenediamine as a constituent of
concern for filter aids, generators would be required only to determine
if p-phenylenediamine is present in their wastes below the listing
levels.
We seek comment on these analytical issues associated with the
potential constituents of concern. We are especially interested in any
information on methods that may reliably resolve the analytical
problems noted above. We also seek comment on the problematic chemicals
we identified, and whether EPA should adopt another approach. One
approach might be to simply avoid using any of these compounds on the
list of constituents of concern due to the analytical problems.
However, due to their potential importance, we believe at this time
that the above approach is a reasonable attempt to use these chemicals
in setting listing levels
on the problematic chemicals
we identified, and whether EPA should adopt another approach. One
approach might be to simply avoid using any of these compounds on the
list of constituents of concern due to the analytical problems.
However, due to their potential importance, we believe at this time
that the above approach is a reasonable attempt to use these chemicals
in setting listing levels. Another approach would be to use the
approach described for the 1,2-diphenylhydrazine/azobenzene pair, i.e.,
if the generators cannot resolve the constituents in the chemical
analysis, they would always assume that the more toxic constituent was
in fact present. We believe this may be overly conservative in some
cases, but solicit comment on this and other possible approaches.
2. Choosing the Risk Assessment Scenarios To Evaluate
For both filter aids and TAM sludges, we evaluated the scenario of
disposal in unlined municipal landfills and assessed the impact of the
release of leachate from these landfills to the groundwater. In past
listings we have found that landfill disposal of wastewater treatment
sludges and similar solids is quite common (e.g., see EPA's recent
listing for petroleum refining wastes, 63 FR 42110; August 6, 1998).
The updated information we collected for both wastes showed that some
generators sent these wastes to municipal landfills. In both cases, EPA
chose to evaluate this scenario. However due to constraints on release
of information claimed as CBI, we cannot discuss in detail the
prevalence of this disposal practice or the extent of other practices.
We used the updated 1997 waste volumes (i.e., waste quantities)
reported by facilities in our modeling of potential releases from
municipal landfills. In the case of filter aids, we combined the filter
aids generated by each facility and arrayed these combined waste
volumes into a distribution that would represent quantities of filter
aids that go to municipal landfills
t of other practices.
We used the updated 1997 waste volumes (i.e., waste quantities)
reported by facilities in our modeling of potential releases from
municipal landfills. In the case of filter aids, we combined the filter
aids generated by each facility and arrayed these combined waste
volumes into a distribution that would represent quantities of filter
aids that go to municipal landfills. We then used this distribution of
waste volumes as a key input parameter into our modeling.
For TAM sludges (excluding sludges associated with TAM pigments
using aniline as a feedstock), the updated data showed few generators
of this waste. One facility sent 57 metric tons of sludge derived
solely from the production of TAM dyes or pigments to a municipal
landfill. This specific sludge was generated from wastewater that arose
from the production of TAM products, and did not include wastewaters
from other production processes. We cannot discuss the volumes or
management practices of the other facilities at this time due to CBI
constraints. We used the one volume associated with the dedicated
sludge in all modeling for TAM sludge disposal in municipal landfills.
Under Federal regulations, generators are free to send either waste
to any Subtitle D municipal landfill. We assumed that any municipal
landfill described in EPA's nation-wide distribution of municipal
landfills was possible, with some geographic limitations reflecting the
locations of the dye and pigment manufacturers (described further
below). Therefore, we used the distribution of data available for each
of the parameters needed to model potential risk associated with
disposal of dye and pigment waste
the location and size of the
landfill (Section 258.1(f)), and States may approve alternative designs
for new units or lateral expansions based on performance standards
(Sec. 258.40(a)(1)). Finally, EPA is in the process of authorizing
States to implement the municipal landfill regulations, and States are
still working to issue permits and bring all landfills up to the
regulatory requirements. Given the existing exemptions in the
regulations, and the uncertainty in how many landfills have liner
systems, we believe it is prudent to base our modeling on landfills
without a liner.
Another reason the modeling of unlined landfills appears prudent is
because industrial wastes also can go to unlined landfills that do not
take municipal waste (i.e., industrial nonhazardous waste landfills),
and thus would not be subject to those standards. We are unaware of any
legal requirement that these wastes could not go to such non-municipal
waste landfills. Given the similarities in the disposal practices
(municipal and industrial nonhazardous waste landfills), we believe
that an unlined landfill scenario is reasonable.
EPA used the approximate geographic locations of the facilities
that generated spent filter aids and TAM sludges to estimate location
parameters needed to conduct the risk assessment. We used geographic
location to identify the soil, climate, and hydrogeologic parameters
used in the fate and transport modeling. Location related parameters
required for the risk assessment and specific inputs and data
distributions used to model risk from these units are described in
detail in the Risk Assessment Background Document (Section 4).
As noted above, there is uncertainty in how many landfills that
might receive these waste have liner systems in place. EPA acknowledges
that a liner system would serve to contain waste leachate, and would
lessen the risk while such a liner system was intact
d data
distributions used to model risk from these units are described in
detail in the Risk Assessment Background Document (Section 4).
As noted above, there is uncertainty in how many landfills that
might receive these waste have liner systems in place. EPA acknowledges
that a liner system would serve to contain waste leachate, and would
lessen the risk while such a liner system was intact. We seek comment
as to whether an alternative regulatory approach should be taken for
wastes sent to landfills with liners or certain environmental controls.
3. The Receptors and Exposure Pathways Evaluated
The primary receptors we considered in this analysis are adults and
children exposed via ingestion (i.e., drinking water) and noningestion
(e.g. showering) exposure pathways to water from groundwater wells
contaminated by the leachate from the municipal landfill receiving
filter aid or TAM sludge wastes. We considered only receptors with
residential drinking water wells for the groundwater pathway. We
assumed all community wells and other municipal water supplies are
treated and, therefore, would not be contaminated with constituents
from the wastes of concern.
We also evaluated receptors from nongroundwater pathways in our
sensitivity analysis. We assumed the receptors for these pathways were
farmers and their children who live in close proximity to the municipal
landfill. We chose these receptors because their exposure results in
the highest potential risk for nongroundwater pathways, which was
appropriate for the initial sensitivity or screening analysis.
Nongroundwater exposure pathways for filter aids and TAM sludges
disposed in municipal landfills result from the emission of vapors from
these landfilled wastes. We evaluated exposure from both direct and
indirect nongroundwater pathways. The direct pathway consists of
dispersal of vapors from the landfill through the air pathway directly
to the receptor via the inhalation
creening analysis.
Nongroundwater exposure pathways for filter aids and TAM sludges
disposed in municipal landfills result from the emission of vapors from
these landfilled wastes. We evaluated exposure from both direct and
indirect nongroundwater pathways. The direct pathway consists of
dispersal of vapors from the landfill through the air pathway directly
to the receptor via the inhalation. Indirect pathways include
deposition to soil, transfer to fruits, vegetables, grain, and forage
(air-to-plant transfer and soil-to-plant transfer), and uptake by
grazing animals. The plant and animal products are then consumed by the
farm family.
E. How Did EPA Estimate Exposure Concentrations?
1. Risk Assessment Methods
To calculate listing levels for constituents of concern, we needed
to determine what concentrations at the point of exposure would be
associated with levels in the wastes. We conducted the risk assessment
in three stages: (1) the sensitivity analysis, (2) the deterministic
analysis, and (3) the probabilistic analysis for the groundwater
pathways. For the nongroundwater pathways, the Agency used results from
the sensitivity analysis to screen out nongroundwater risks, because
they were not significant relative to potential groundwater risks
associated with disposal of wastes in landfills.
a. Sensitivity Analysis. The purpose of our sensitivity analysis
was to identify the most sensitive or risk-driving parameters in the
risk assessment model and to determine high-end and central tendency
values for subsequent use in the deterministic analysis. A high-end
parameter corresponds to its 90th or 10th percentile value depending on
whether a high or low value of that parameter results in a higher
predicted risk. We conducted the sensitivity analysis by varying each
parameter or set of linked parameters to high ends one at a time, while
holding all other variables in the analysis at central tendency
quent use in the deterministic analysis. A high-end
parameter corresponds to its 90th or 10th percentile value depending on
whether a high or low value of that parameter results in a higher
predicted risk. We conducted the sensitivity analysis by varying each
parameter or set of linked parameters to high ends one at a time, while
holding all other variables in the analysis at central tendency. We
then compared the risk results using a single high-end parameter to the
results obtained when all values are set at central tendency. Using
this method, we identified the two most sensitive high end parameters
that resulted in the highest risks. We then set these parameters to
their high-end values in the subsequent deterministic analysis. For the
groundwater pathway, we used the sensitivity analysis to identify high-
end parameters for use in the deterministic assessment of risk from
groundwater.
For the nongroundwater pathway, we were able to use the results
from the sensitivity analysis as a screening level analysis of
nongroundwater risks. Originally, we intended to use the nongroundwater
sensitivity analysis to identify the most sensitive parameters for use
in a deterministic analysis of nongroundwater risks from the dye and
pigment waste streams. However, we were able to use the results of the
nongroundwater sensitivity analysis to screen out or eliminate
nongroundwater risks as a primary concern for dye and pigment industry
wastes. We screened out nongroundwater risks by comparing the results
of the nongroundwater sensitivity analysis to the results of the
istic analysis of nongroundwater risks from the dye and
pigment waste streams. However, we were able to use the results of the
nongroundwater sensitivity analysis to screen out or eliminate
nongroundwater risks as a primary concern for dye and pigment industry
wastes. We screened out nongroundwater risks by comparing the results
of the nongroundwater sensitivity analysis to the results of the
groundwater sensitivity analysis, which we performed using the same
inputs for common parameters. In all cases, the groundwater risk
analysis produced higher risk estimates for all constituents. Since the
purpose of this analysis was to set risk-based concentration limits, we
focused our analysis on the pathway of most concern (i.e., highest
risk) to determine protective concentrations. Because the groundwater
pathway presented the highest risk, we only evaluated the groundwater
pathway further using deterministic and Monte Carlo analyses. In other
words, risk-based concentrations set based on groundwater pathway risks
will also be protective of nongroundwater pathway risks. Based on this
finding, no further modeling of nongroundwater risks was conducted. The
Risk Assessment Background Document describes the sensitivity analysis
for both groundwater and nongroundwater pathways and presents the
results in Appendices A and H.
b. Deterministic Analysis. The ``deterministic'' method uses single
values for input parameters in the models to produce a point estimate
of risk or hazard. For this analysis, we used a double high-end risk
assessment. In this method, we set the two parameters identified to be
most sensitive at their high-end values and all other parameters are
set at central tendency. A central tendency risk estimate is the point
estimate in which all variables are set at central tendency values. We
presume the high-end risk estimate to be a plausible estimate of
individual risk for those persons at the upper end of the risk
distribution
we set the two parameters identified to be
most sensitive at their high-end values and all other parameters are
set at central tendency. A central tendency risk estimate is the point
estimate in which all variables are set at central tendency values. We
presume the high-end risk estimate to be a plausible estimate of
individual risk for those persons at the upper end of the risk
distribution. By using these descriptors we intend to convey estimates
of exposure in the upper end of the distribution (i.e., above the 90th
percentile), while avoiding estimates that are beyond the true
distribution. (See the EPA guidance memo entitled, Guidance on Risk
Characterization for Risk Managers, 1992; hereafter known as the
Habicht memo, 1992). We applied the deterministic methodology to assess
groundwater pathway risks from disposal of spent filter aid and TAM
sludges in municipal landfills. The parameters that we found to be the
two key high-end parameters varied somewhat by chemical and waste.
However, these parameters were some combination of waste quantity, well
location, and duration of exposure.
c. Probabilistic Analysis (Monte Carlo Method). In the
probabilistic analysis, we vary sensitive parameters for which
distributions of data are available. Parameters varied for this
analysis include waste volumes, landfill size, parameters related to
the location of the landfill such as climate and hydrogeologic data,
location of the receptor, and exposure factors (e.g., drinking water
ingestion rates). The probabilistic analysis is conducted using a Monte
Carlo methodology. Monte Carlo analysis provides a means of quantifying
some variability and uncertainty in risk assessments by using
distributions that describe the full range of values that the various
input parameters may have. Some of the parameters in the probabilistic
analysis are set as constant values because (1) there are insufficient
data to develop a distribution, (2) simplifying assumptions are made,
nte Carlo analysis provides a means of quantifying
some variability and uncertainty in risk assessments by using
distributions that describe the full range of values that the various
input parameters may have. Some of the parameters in the probabilistic
analysis are set as constant values because (1) there are insufficient
data to develop a distribution, (2) simplifying assumptions are made,
(3) site specific constants are available, or (4) the analysis has not
been shown to be sensitive to the values of the parameter, that is,
even if the parameter is varied, the risk results do not vary
significantly.
Monte Carlo simulation is a statistical technique that calculates
an individual risk value or hazard quotient for each category of
parameters that affect or determine risk. For each calculation, the
Monte Carlo simulation uses parameter values that are randomly selected
from the distribution of values available for each parameter. The range
of values selected for the input parameters reflects the distribution
of values corresponding to each input parameter. The repetitive
calculations take many randomly selected combinations of input
parameters to generate a range of risk results. Based on the
distribution of the output, we can determine a risk or hazard level
representing the high end (e.g., 90th or 95th percentile) or central
tendency (i.e., 50th percentile). Although the simulation is internally
complex, commercial software performs the calculations as a single
operation, presenting a distribution of risk results. From these
results, we can determine the percentile distribution of exposure point
concentrations and risks for the selected risk assessment scenario. We
assessed potential groundwater pathway risks from disposal of filter
aid and TAM wastes in municipal landfills using the probabilistic risk
assessment method
the calculations as a single
operation, presenting a distribution of risk results. From these
results, we can determine the percentile distribution of exposure point
concentrations and risks for the selected risk assessment scenario. We
assessed potential groundwater pathway risks from disposal of filter
aid and TAM wastes in municipal landfills using the probabilistic risk
assessment method.
Monte Carlo simulation can be used to simulate the effects of
natural variability and informational uncertainty that often accompany
many actual environmental conditions. Further, information on the range
and likelihood of possible values for these parameters is produced
using this technique. When compared with alternative approaches for
assessing parameter uncertainty or variability, the Monte Carlo
technique has the advantages of very general applicability, no inherent
restrictions on input distributions or input-output relationships, and
relatively straightforward computations. Also, Monte Carlo application
results can be used to satisfactorily calculate uncertainty, and to
quantify the degree of conservatism used. With deterministic analyses,
an alternative to Monte Carlo, it is often not possible to quantify the
level of protection represented by the results. However, some potential
limitations may exist when applying Monte Carlo techniques in modeling
efforts. Variability (inherent variation in a measure over time and
space) and uncertainty (lack of knowledge) are often difficult to
distinguish within applications. Also, one must account for
correlations among the various data parameters to avoid distorting
results. As explained in Section III.H, we relied on the Monte Carlo
approach to set listing levels for today's proposal.
2. Fate and Transport Modeling
The risk analysis employs several key fate and transport models.
The models include a landfill partitioning model based upon the
equations presented in a series of articles by Jury et al
s among the various data parameters to avoid distorting
results. As explained in Section III.H, we relied on the Monte Carlo
approach to set listing levels for today's proposal.
2. Fate and Transport Modeling
The risk analysis employs several key fate and transport models.
The models include a landfill partitioning model based upon the
equations presented in a series of articles by Jury et al. We used this
model to estimate the concentration of leachate from the landfill and
the emission rate for volatile constituents from the landfill. We
applied EPA's Industrial Source Complex Short Term, version 3 (ISCST3)
to estimate the dispersion and deposition of vapors emitted from the
municipal landfill. For estimating the concentration of constituents of
concern at the residential drinking water well, we used the groundwater
model EPACMTP or EPA's Composite Model for Leachate Migration with
Transformation Products. Further details and references for these
models are presented in the Risk Assessment Background Document
(Section 5.2.2).
a. Landfill Partitioning Model. We used the Jury equations to
estimate fate and transport of constituents in the nongroundwater
pathways from the landfill to the receptor and to estimate leachate
from the landfill. Using a model based on the Jury equations, we
projected the contaminant loss from a landfill due to volatilization,
run-off, degradation, and leaching. The Jury equations partition the
waste in the landfill to waste, air, and pore water and calculate
potential losses from leaching, volatilization, and degradation. The
landfill partitioning model evaluates contaminant losses over both the
active waste disposal period and after the landfill is closed. We used
the landfill partitioning model to conduct the
,
run-off, degradation, and leaching. The Jury equations partition the
waste in the landfill to waste, air, and pore water and calculate
potential losses from leaching, volatilization, and degradation. The
landfill partitioning model evaluates contaminant losses over both the
active waste disposal period and after the landfill is closed. We used
the landfill partitioning model to conduct the
sensitivity, deterministic, and Monte Carlo analyses.
b. Air Model. We used the ISCST3 air dispersion and deposition
model to estimate the vapor air concentrations and deposition rates
needed to develop relative risk estimates associated with vapor air
emissions from the municipal landfill. We estimated air pathway risks
using emissions estimates from the landfill partitioning model as
inputs to the ISCST3 air model, and using ISCST3 to estimate the air
concentration and deposition of vapor for each constituent at receptor
locations. This modeling step was only needed for the sensitivity
analysis to estimate risks from non-groundwater pathways.
c. Groundwater Model. We used the EPACMTP groundwater model to
estimate the concentration of constituents of concern at the
residential drinking water well. We conducted the groundwater modeling
using six surrogate compounds to represent the movement of all
constituents of concern through the groundwater pathway. Identification
of surrogate compounds provides a means of minimizing the modeling runs
required to model the large number of constituents evaluated for this
assessment. For this assessment, organic constituents are grouped into
six categories based on like chemical and physical properties. Sorption
potential and hydrolysis rate are the key parameters used to group
constituents; however, for the constituents of concern in today's
proposed rule, hydrolysis was not important
runs
required to model the large number of constituents evaluated for this
assessment. For this assessment, organic constituents are grouped into
six categories based on like chemical and physical properties. Sorption
potential and hydrolysis rate are the key parameters used to group
constituents; however, for the constituents of concern in today's
proposed rule, hydrolysis was not important. Therefore, the only
constituent-specific parameter of importance for transport of the
organic compounds of interest was the sorption potential (i.e., the
organic carbon partition coefficient, Koc; this is a measure
of the tendency for a chemical to adsorb to organic material in soils).
For computational efficiency, we only modeled the surrogate constituent
in each category, and then applied the modeling results for the
surrogate to each constituent in the category. We found that the
dilution and attenuation of the constituents we evaluated did not vary
significantly (i.e., less that a factor of 2), even with larger
differences in Koc. Thus, the use of surrogates did not
introduce any appreciable uncertainty into the final results. See
Appendix C of the Risk Assessment Background Document for details of
the designation of constituent categories and identification of
surrogate compounds.
We used the EPACMPT model to conduct the sensitivity analysis,
deterministic analysis, and Monte Carlo analysis for the groundwater
pathway. The groundwater pathway modeling yields the groundwater
exposure concentrations resulting from the release of waste
constituents from the landfill. Precipitation that percolates through
the waste unit generates leachate, which can infiltrate from the bottom
of the landfill into the subsurface. The waste constituents dissolved
in the leachate (as predicted by the partitioning model) are then
transported via aqueous phase migration through the vadose zone to the
underlying saturated zone and then down gradient to a ground water
receptor well
cipitation that percolates through
the waste unit generates leachate, which can infiltrate from the bottom
of the landfill into the subsurface. The waste constituents dissolved
in the leachate (as predicted by the partitioning model) are then
transported via aqueous phase migration through the vadose zone to the
underlying saturated zone and then down gradient to a ground water
receptor well. We project the concentration at the intake point of a
hypothetical groundwater drinking water well or receptor well, located
at a specified distance from the down gradient edge of the waste
management unit.
We located the residential wells down gradient from the landfill
and within the top ten meters of a plume of groundwater contaminated by
the leachate from the municipal landfill. As noted previously, we used
distances of receptor wells from waste management units from EPA's
National Survey of Municipal Landfills. The distance from the landfill
to the receptor well, and the location of the well in relation to the
plume of contaminated groundwater, are important parameters in the
groundwater model. This is because the projected concentrations of
constituents at the well, and the corresponding risks, increase as the
well location is moved closer to the source within the plume.
For the Monte Carlo analysis, we placed the receptor well
downgradient from the waste management unit at a radial distance of up
to 1,610 m; the distance for each simulation was taken from the
distribution of distances gathered by EPA in its survey noted above. We
assumed the lateral location of the well to be randomly distributed
within the estimated lateral extent of the plume. For the deterministic
analysis, the downgradient receptor well location was fixed within the
lateral extent of the plume (most often at the high end value of 102
meters from the landfill)
s taken from the
distribution of distances gathered by EPA in its survey noted above. We
assumed the lateral location of the well to be randomly distributed
within the estimated lateral extent of the plume. For the deterministic
analysis, the downgradient receptor well location was fixed within the
lateral extent of the plume (most often at the high end value of 102
meters from the landfill).
The objective of this ground-water modeling was to compute the
amount of dilution and attenuation a contaminant may undergo as it
migrates from a landfill to a ground-water well. The amount of dilution
and attenuation is expressed as a dilution/attenuation factor (DAF),
which represents the ratio of the initial leachate concentration
leaving the landfill to the ground-water receptor well concentration.
The high-end DAFs for the different constituents did not vary much for
the two wastes, i.e., the DAFs were in the range of 3 to 5.
The groundwater model accounts for the following processes
affecting contaminant fate and transport: advection, hydrodynamic
dispersion, linear or nonlinear equilibrium sorption, chained first-
order decay reactions, and dilution from recharge in the saturated
zone. EPACMTP was run in both deterministic mode and Monte Carlo mode.
In the deterministic mode, we set the two most sensitive variables to
their high end values, while keeping all other parameters set at
central tendency. In the probabilistic Monte Carlo mode, the model
randomly selected parameter values from their respective statistical
distributions. The Monte Carlo procedure allows assessment of the
uncertainty associated with ground-water well concentrations that
result from uncertainty and variability in climatic and hydrogeologic
characteristics of waste management units across the range of locations
associated with the Dyes and Pigments industry.
F. What Exposure Assumptions and Toxicity Levels Did EPA Use?
tatistical
distributions. The Monte Carlo procedure allows assessment of the
uncertainty associated with ground-water well concentrations that
result from uncertainty and variability in climatic and hydrogeologic
characteristics of waste management units across the range of locations
associated with the Dyes and Pigments industry.
F. What Exposure Assumptions and Toxicity Levels Did EPA Use?
We used values from EPA's Exposure Factors Handbook (EPA, 1997) to
set the exposure assumptions for this analysis. We applied the
recommended values for the central tendency and high end intake rates
in the deterministic analysis, and we used a distribution of values
developed from the data presented in the Exposure Factors Handbook in
the Monte Carlo analysis. Section 6.0 of the Risk Assessment Background
Document discusses these values in detail.
The health benchmark data used in the analysis are based upon the
values presented in the Integrated Risk Information System (IRIS)
online database of verified health benchmarks or in the Health Effects
Assessment Summary Tables (HEAST) document. Appendix E of the Risk
Assessment Background Document contains toxicological profiles used in
our analysis. The studies used as the basis for these benchmarks have
been reviewed and summaries of these studies, along with references to
the complete studies, are presented in Appendix E of the Risk
Assessment Background Document.
G. What Uncertainties Are Associated With The Risk Assessment?
Uncertainty is inherent in the risk assessment process. It occurs
because the risk assessment process is complex, and variability is
inherent in the environment. We may classify the sources of uncertainty
as parameter uncertainty and variability, exposure
s, are presented in Appendix E of the Risk
Assessment Background Document.
G. What Uncertainties Are Associated With The Risk Assessment?
Uncertainty is inherent in the risk assessment process. It occurs
because the risk assessment process is complex, and variability is
inherent in the environment. We may classify the sources of uncertainty
as parameter uncertainty and variability, exposure
scenario uncertainty, and model uncertainty. Parameter uncertainty
occurs when parameters appearing in equations cannot be measured
precisely and/or accurately. Variability refers to the normal
variations in physical and biological processes that we cannot reduce
with additional data. We have addressed variability in this risk
assessment by using a probabilistic analysis. Exposure scenario
uncertainty occurs because of the inability to measure exposure of
receptors to constituents of concern. Model uncertainty is associated
with all models used in risk assessment and occurs because computer
models require simplifications of reality, and thus exclude some
variables and interactions that influence fate and transport but cannot
be included in models due to complexity or lack of data. We discuss
each of these issues in detail in Section 8 of the Risk Assessment
Background Document.
One important area of uncertainty that we believe should be noted
is the uncertainty involving estimates of risks to children from
carcinogenic compounds. We used the same overall approach for
estimating cancer risks in both adults and children from the dye and
pigment waste streams evaluated. We modified the exposure factors for
children to account for differences between adult and child receptors
(e.g., body weight, exposure duration). However, we recognize that
significant uncertainties and unknowns exist regarding the estimation
of lifetime cancer risks in children. Methodologies for estimating
environmental threats to children's health are relatively new
ste streams evaluated. We modified the exposure factors for
children to account for differences between adult and child receptors
(e.g., body weight, exposure duration). However, we recognize that
significant uncertainties and unknowns exist regarding the estimation
of lifetime cancer risks in children. Methodologies for estimating
environmental threats to children's health are relatively new. They are
currently being debated within the scientific community, and will
continue to evolve. The analysis of cancer risks in children undertaken
for this assessment has not been externally peer reviewed.
H. What Risk Level Do the Concentration Levels Represent?
In calculating concentration limits for the two wastes, we assumed
the residential drinking water well concentration is equal to EPA
established protective or health-based level for each constituent for
the most sensitive receptor (adult or child). Protective concentrations
are those at which adverse health effects from any single constituent
present in contaminated drinking water and/or water used for bathing or
showering do not exceed a one in 100,000 (1 x 10-5)
individual lifetime cancer risk or a non-cancer hazard quotient of 1
(where the hazard quotient is the ratio of the concentration in the
water to the concentration at which no non-cancer effects are
expected). The use of these risk levels is consistent with the initial
cancer-risk and HQ ``levels of concern'' that we described in the
discussion on EPA's hazardous waste listing policy in the 1994 proposed
rule for dye pigment wastes (see 59 FR 66075). As noted previously, we
based the concentrations on the groundwater pathway, which is the
pathway of most concern for all constituents of concern for this
industry when disposed in municipal landfills. Section 5 of the Risk
Assessment Background Document provides the methodology we used to
derive risk limiting waste concentrations in greater detail.
I. What Are the Proposed Listing Levels?
. As noted previously, we
based the concentrations on the groundwater pathway, which is the
pathway of most concern for all constituents of concern for this
industry when disposed in municipal landfills. Section 5 of the Risk
Assessment Background Document provides the methodology we used to
derive risk limiting waste concentrations in greater detail.
I. What Are the Proposed Listing Levels?
Table III-3 presents the risk-based concentration levels for all
potential constituents of concern calculated for both spent Filter Aids
and TAM sludges based on our risk assessment. These levels represent
protective concentrations for constituents that may be present in the
wastes, and are based on the receptor that yielded the lowest allowable
waste concentration (i.e, adult or child). Using the partitioning model
described above, we calculated protective levels for constituents in
both the waste itself and for leachate that is released from the
landfill. We are proposing to set the concentration levels in the
listing at the levels calculated for the constituents in the two
wastes. If you generate either waste under consideration, your waste
concentrations would have to be below these levels, or else your waste
will be a listed hazardous waste. Therefore, under this proposal, you
would be assessing constituent concentrations in the waste itself.
1. Selection of Listing Levels in Wastes Versus Leachate
We considered using the landfill leachate levels in Table III-2
instead of the waste levels to define the listed waste. We could do
this if we require generators to evaluate their wastes using a test
designed to predict leaching from landfills. The Toxicity
Characteristic Leaching Procedure (TCLP) is one possible method
available. The Toxicity Characteristic (TC) regulation uses the TCLP to
decide whether wastes are hazardous under this characteristic (see 40
CFR 261.24). However, we decided not to use the TCLP approach for
several reasons
generators to evaluate their wastes using a test
designed to predict leaching from landfills. The Toxicity
Characteristic Leaching Procedure (TCLP) is one possible method
available. The Toxicity Characteristic (TC) regulation uses the TCLP to
decide whether wastes are hazardous under this characteristic (see 40
CFR 261.24). However, we decided not to use the TCLP approach for
several reasons. First, we did not perform TCLP analysis for these
constituents in any of the dye and pigment wastes examined. Thus, we
are uncertain how the method might perform for the wastes at issue. The
partitioning model also factors in the placement of the wastes into the
landfill and provides a leaching rate that reflects how the volumes of
wastes are assumed to be disposed over time. The TCLP approach is
appropriate for defining levels of concern under the TC for all wastes
on a nationwide basis, where we have no specific information on waste
quantities disposed. In today's proposed rule we have information on
the specific quantities of the two selected wastes in the dyes and
pigments industries. Finally, we believe that the analysis of the waste
itself is more straightforward to implement, and would not require
measuring levels in a derived leachate that are much lower than those
in the waste. Therefore, we chose to propose the concentration based
levels for the waste itself.
However, the TCLP does represent an actual measurement of leach
potential as opposed to a value generated by a model. Thus, the Agency
may still consider a final regulation based on the TCLP, depending on
comments received and additional information provided.
2. Selection of Probabilistic Versus Deterministic Modeling Results
The constituent concentrations in Table III-3 reflect the results
of the probabilistic modeling assessment. We chose to use the
probabilistic results, rather than rely on the deterministic results
gency
may still consider a final regulation based on the TCLP, depending on
comments received and additional information provided.
2. Selection of Probabilistic Versus Deterministic Modeling Results
The constituent concentrations in Table III-3 reflect the results
of the probabilistic modeling assessment. We chose to use the
probabilistic results, rather than rely on the deterministic results.
While the Agency has used the results of deterministic analyses for
past listing decisions, EPA has more recently used Monte Carlo analyses
for additional verification (see Petroleum Listing final rule, 63 FR
42110; August 6, 1998). As we have developed and refined the Monte
Carlo approach, we believe it provides some distinct advantages. As
noted earlier, when compared with alternative approaches for assessing
parameter uncertainty or variability, the probabilistic technique has
the advantages of general applicability and no inherent restrictions on
input distributions or input-output relationships.
An additional factor the Agency considered was the highly variable
nature of the data available. The constituents of concern, their
concentrations, and waste volumes can be highly variable across the
different industry processes, a factor which made the Agency reluctant
to rely on selected point estimates for its assessment. Also of
particular concern was the difficulty we found in choosing what set of
parameters would truly represent a ``high-end'' analysis for multiple
pathways, constituents, and locations. The issues associated with
choosing high-end parameters are discussed in the Risk Assessment
Background
sses, a factor which made the Agency reluctant
to rely on selected point estimates for its assessment. Also of
particular concern was the difficulty we found in choosing what set of
parameters would truly represent a ``high-end'' analysis for multiple
pathways, constituents, and locations. The issues associated with
choosing high-end parameters are discussed in the Risk Assessment
Background
Document, which presents the deterministic as well as the probabilistic
results.
The probabilistic simulations used in this proposed rulemaking
assessed the full distributions of critical input data (e.g., distance
to well, waste volumes, landfill area) to randomly generate receptor
well concentrations of key constituents for certain landfill
situations, and then combined the results from many runs to produce a
probability distribution of risks. We were then able to choose points
along the probability distribution of risk for comparison to the high-
end analysis. For example, a risk that corresponds to the 90th
percentile for a specific waste constituent in a landfill means that
the risk would be below this level in 90 percent of the runs.
The concentration levels in Table III-3 represent the probabilistic
modeling results at the 90th percentile. As discussed previously, we
are attempting to calculate estimates of exposure in the upper end of
the distribution (i.e., above the 90th percentile), while avoiding
estimates that are beyond the true distribution. (See Habicht memo,
1992.) The Agency's policies do not indicate that there is any
particular point on a Monte Carlo distribution that should be the point
at which the Agency regulates or does not regulate
we
are attempting to calculate estimates of exposure in the upper end of
the distribution (i.e., above the 90th percentile), while avoiding
estimates that are beyond the true distribution. (See Habicht memo,
1992.) The Agency's policies do not indicate that there is any
particular point on a Monte Carlo distribution that should be the point
at which the Agency regulates or does not regulate. This conceptual
range is not meant to precisely define the limits of this descriptor,
but should be used by the assessor as a target range for characterizing
``high-end risk.'' Therefore, a high-end estimate that falls within the
range (above the 90th percentile but still realistically on the
distribution) is a reasonable basis for a decision.
We believe that the 90th percentile levels calculated for the waste
concentrations in today's proposed rule are protective. For filter
aids, the high-end deterministic results gave concentrations that were
somewhat higher than the 90th percentile levels from the probabilistic
analysis (by a factor of 2-4 fold). Therefore, we believe that using
the 90th percentile values (as opposed to higher percentile values)
provides results that are more consistent with previous listing
determinations based on high-end deterministic assessments. For TAM
sludges, the 90th percentile probabilistic levels are also close to the
deterministic results, although for this waste the probabilistic levels
for most constituents are slightly above the deterministic values
(approximately two-fold). Thus, the 90th percentile results appear to
agree reasonably well overall with the deterministic results.
Furthermore, the probabilistic DAFs predicted for transport of landfill
leachate from the landfill to the receptor well were already quite low
at the 90th percentile (i.e., 2-5), also suggesting that the 90th
percentile is adequately protective
erministic values
(approximately two-fold). Thus, the 90th percentile results appear to
agree reasonably well overall with the deterministic results.
Furthermore, the probabilistic DAFs predicted for transport of landfill
leachate from the landfill to the receptor well were already quite low
at the 90th percentile (i.e., 2-5), also suggesting that the 90th
percentile is adequately protective.
We are soliciting comments on both the use of the probabilistic
modeling results, rather than the deterministic analyses, and also our
use of the 90th percentile risk level, rather than any other level. For
example, the 95th percentile probabilistic results yields
concentrations that are about two-fold lower. Details of the
deterministic modeling results, and levels calculated using other
percentiles from the probabilistic analysis, are given in the Risk
Assessment Background Document (Appendix F). We also seek comment on
the setting of the regulatory levels for the waste itself, rather than
the option of using the TCLP values.
Table III-3.--Calculated Risk-Based Concentration Levels for Possible Constituents of Concern for Dye and
Pigment Wastes\1\
----------------------------------------------------------------------------------------------------------------
Concentration levels for Concentration levels for TAM
filter aids ** sludges
Constituents ---------------------------------------------------------------
Leachate (mg/ Leachate (mg/
Waste (mg/kg) ml) Waste (mg/kg) ml)
----------------------------------------------------------------------------------------------------------------
Aniline......................................... .............. .............. 17 0.03
Benzaldehyde.................................... .............. .............. 5000 5.6
Benzene......................................... .............. .............. 370 0.11
Benzidine....................................... .............. .............. 0.027 0.000023
Chloroaniline, p-............................... .............
............................. .............. .............. 17 0.03
Benzaldehyde.................................... .............. .............. 5000 5.6
Benzene......................................... .............. .............. 370 0.11
Benzidine....................................... .............. .............. 0.027 0.000023
Chloroaniline, p-............................... .............. .............. 250 0.25
Chlorobenzene................................... .............. .............. 36 0.0036
Chloroform...................................... .............. .............. 100 0.042
Cresol, p-...................................... .............. .............. 330 0.33
Dichlorobenzene, 1,2-........................... .............. .............. 1100 0.043
Dimethoxybenzidine, 3,3'-....................... .............. .............. 520 0.38
Dimethylaniline, N,N-........................... .............. .............. 300 0.11
Diphenylamine................................... .............. .............. 27,000 1.1
N-Nitrosodiphenylamine.......................... .............. .............. 7,400 0.62
Diphenylhydrazine, 1,2-......................... .............. .............. 31 0.0042
Azobenzene...................................... .............. .............. 720 0.013
Formaldehyde.................................... .............. .............. 7000 11
Naphthalene..................................... .............. .............. 17 0.0028
Phenol.......................................... .............. .............. 28,000 34
Phenylenediamine, o-(2-aminoaniline)............ .............. .............. 61 0.11
Phenylenediamine, p-(4-aminoaniline)............ .............. .............. 5,000 10
Toluidine, o-(2-aminotoluene)................... .............. .............. 13 0.022
Toluidine, p-(4-aminotoluene)................... .............. .............. 23 0.029
Toluidine, 5-nitro-o-(2-Methyl-5-nitroaniline).. .............. .............
aniline)............ .............. .............. 61 0.11
Phenylenediamine, p-(4-aminoaniline)............ .............. .............. 5,000 10
Toluidine, o-(2-aminotoluene)................... .............. .............. 13 0.022
Toluidine, p-(4-aminotoluene)................... .............. .............. 23 0.029
Toluidine, 5-nitro-o-(2-Methyl-5-nitroaniline).. .............. .............. 220 0.15
(**)
----------------------------------------------------------------------------------------------------------------
\1\ Levels represent the 90th percentile risk derived from the probabilistic analysis.
** Relevant data are not included at the present time for a number of constituents due to business
confidentiality concerns.
IV. Proposed Listing Determinations and Regulations
A. What Are the Proposed Regulations for the Two Wastes?
We are proposing that, if you generate either of the two categories
of dye and pigment wastes at issue, you must either determine whether
or not your waste is a listed hazardous waste within a specified time,
or assume that it is hazardous as generated. Your waste would become a
listed hazardous waste if it contains any of the constituents of
concern at a concentration equal to or greater than the hazardous
concentration identified for that constituent. You must make a
determination that all of the constituents of concern in your waste are
below the hazardous concentrations to claim that your wastes remain
nonhazardous. We are proposing the following specific regulatory
language for the two wastes:
ains any of the constituents of
concern at a concentration equal to or greater than the hazardous
concentration identified for that constituent. You must make a
determination that all of the constituents of concern in your waste are
below the hazardous concentrations to claim that your wastes remain
nonhazardous. We are proposing the following specific regulatory
language for the two wastes:
K167 Spent filter aids, diatomaceous earth, or adsorbents used
in the production of azo, anthraquinone, or triarylmethane dyes,
pigments, or FD&C colorants, unless these wastes do not contain any
of the constituents identified in Sec. 261.32(b)(3)(iii) at a
concentration equal to or greater than the hazardous level set for
that constituent as demonstrated by the procedures specified in
Sec. 261.32(b).
K168 Wastewater treatment sludges from the production of
triarylmethane dyes and pigments (excluding triarylmethane pigments
using aniline as a feedstock), unless these wastes do not contain
any of the constituents identified in Sec. 261.32(b)(3)(iii) at a
concentration equal to or greater than the hazardous level set for
that constituent as demonstrated by the procedures specified in
Sec. 261.32(b).
The constituents and levels in these listing descriptions would be
those given in Tables IV-1 for Filter Aids and Table IV-2 for TAM
sludges. Section V describes the steps you must follow to implement the
concentration-based listing.
We solicit comment on the proposed list of constituents and their
levels. Specifically, based on the rather high levels set for some
constituents (e.g., diphenylamine, formaldehyde for TAM sludges), EPA
is considering removing these. These levels may be unlikely in these
wastes, and may not merit analysis. We seek any information that may
assist us in deciding on whether we should retain all of these
constituents
the proposed list of constituents and their
levels. Specifically, based on the rather high levels set for some
constituents (e.g., diphenylamine, formaldehyde for TAM sludges), EPA
is considering removing these. These levels may be unlikely in these
wastes, and may not merit analysis. We seek any information that may
assist us in deciding on whether we should retain all of these
constituents. We also solicit comment as to whether any other
constituents (e.g., any others in Table III-3) should be added to the
regulatory lists in Tables IV-1 or IV-2.
Table IV-1.--Concentration Levels for Spent Filter Aids
------------------------------------------------------------------------
Concentration
Constituents levels (mg/
kg)**
------------------------------------------------------------------------
Aniline
Benzaldehyde
Chloroaniline, p-
Cresol, p-
Dimethylaniline, N,N-
Dimethoxybenzidine, 3,3'-
Diphenylamine
Diphenylhydrazine, 1,2-
Formaldehyde
Naphthalene
Phenol
Phenylenediamine, p-
Toluidine, o-
Toluidine, p-
(**)
(**)
------------------------------------------------------------------------
** Relevant data are not included at the present time due to business
confidentiality concerns.
Table IV-2.--Concentration Levels for TAM Sludges
------------------------------------------------------------------------
Concentration
Constituent levels (mg/
kg)
------------------------------------------------------------------------
Benzaldehyde............................................. 5000
Dimethylamine, N,N-...................................... 300
Diphenylamine............................................ 27,000
Formaldehyde............................................. 7000
Toluidine, o-............................................ 13
Toluidine, p-............................................ 23
(**) (** )
------------------------------------------------------------------------
**Relevant data are not included at the present time due to business
confidentiality concerns.
............................ 27,000
Formaldehyde............................................. 7000
Toluidine, o-............................................ 13
Toluidine, p-............................................ 23
(**) (** )
------------------------------------------------------------------------
**Relevant data are not included at the present time due to business
confidentiality concerns.
As required under Sec. 261.30(b), we are adding those constituents
that are the bases for listings to Appendix VII of Part 261, ``Basis
for Listing Hazardous Waste.'' Thus, we are proposing to add the
constituents in Table IV-1 for K167 (filter aids), and the constituents
in Table IV-2 for K168 (TAM sludges) to Appendix VII. In addition,
several constituents in Tables IV-1 and IV-2 are not currently listed
on Appendix VIII to Part 261, ``Hazardous Constituents.'' EPA places
constituents on Appendix VIII if they have been shown in scientific
studies to have toxic, carcinogenic, mutagenic, or teratogenic effects
on humans or other life forms (see 261.11(a)(3)). The Risk Assessment
Background Document contains the detailed toxicological data for all
constituents we evaluated, including the specific chemicals that we are
proposing to add to Appendix VIII in today's rule: benzaldehyde, N,N-
dimethylaniline, p-cresol, and p-phenylenediamine, and another
chemical, the identity of which is not given due to business
confidentiality concerns. While cresol and phenylenediamine are
currently listed on Appendix VIII, the precise isomers are not
specified. Therefore, we are proposing to add these specific isomers.
If, in response to comment, we decide to add any additional
constituents to the chemicals of concern in either concentration-based
listing, then we would also add those constituents to Appendix VII, and
to Appendix VIII, if necessary
ol and phenylenediamine are
currently listed on Appendix VIII, the precise isomers are not
specified. Therefore, we are proposing to add these specific isomers.
If, in response to comment, we decide to add any additional
constituents to the chemicals of concern in either concentration-based
listing, then we would also add those constituents to Appendix VII, and
to Appendix VIII, if necessary.
In proposing to promulgate a concentration-based listing for filter
aids and TAM sludges under 40 CFR 261.11(a)(3), we considered the
factors given under 40 CFR 261.11(a)(3) and believe that these wastes
pose a substantial present or potential hazard to human health or the
environment at the proposed listing levels. We considered nearly all of
these factors as part of the risk assessment described in today's rule.
Specifically, we considered the constituents' toxicity/concentration,
mobility, persistence, and bioaccumulation potential in setting the
concentration-based levels (corresponding to factors (I) through (vi)
given in Sec. 261.11(a)(3)). As described in the risk assessment
section, we considered municipal landfills as the ``plausible''
management practice (factor (vii)), and evaluated the waste quantities
generated by facilities (factor viii). Concerning factor (ix), we
examined damage cases for the dye and pigment industries for the 1994
proposed rule (see Risk Assessment Support for Dye and Pigment Listing
Determination, November 29 1994; document number S0333, EPA Docket No.
F-94-DPLP-FFFFF). However none of those cases provide any information
on the possible damages associated with the two wastes at issue in
today's proposal. Finally, we considered other regulatory programs
(factor (x)), when appropriate. No other regulatory program EPA
identified adequately addressed the risks posed by the wastes. However,
as noted in Section IV.C, we considered the protection afforded by the
Clean Water Act, and the regulations being considered for leachate from
landfills
ciated with the two wastes at issue in
today's proposal. Finally, we considered other regulatory programs
(factor (x)), when appropriate. No other regulatory program EPA
identified adequately addressed the risks posed by the wastes. However,
as noted in Section IV.C, we considered the protection afforded by the
Clean Water Act, and the regulations being considered for leachate from
landfills. As a result of this consideration, we are proposing to
temporarily defer any regulation of landfill leachate that may be
derived from the wastes proposed for listing, provided certain
conditions are met.
B. What Are We Proposing for Anthraquinone Sludges?
We are proposing not to list wastewater treatment sludges from the
production of anthraquinone dyes and pigments. As described earlier in
this notice, the only constituents that were
found in wastes that could be attributed to anthraquinone production (
the identities are not given due to business confidentiality concerns)
do not have health-based benchmarks. We did not receive any data in
comments on the 1994 proposed rule that would allow us to estimate such
benchmarks.
Discussion of the details of waste generation and management for
this waste cannot be released at this time due to business
confidentiality concerns.
Therefore, we are proposing not to list anthraquinone sludges
because we cannot identify any health threat from these wastes. Further
discussion on the generation of this waste cannot be released at this
time due to CBI constraints. We do not find any demonstrated risk from
the constituents that we can attribute to anthraquinone production. We
seek comment on this decision not to list this waste.
C. What Is the Status of Landfill Leachate From Previously Disposed
Wastes?
dentify any health threat from these wastes. Further
discussion on the generation of this waste cannot be released at this
time due to CBI constraints. We do not find any demonstrated risk from
the constituents that we can attribute to anthraquinone production. We
seek comment on this decision not to list this waste.
C. What Is the Status of Landfill Leachate From Previously Disposed
Wastes?
Leachate derived from the treatment, storage, or disposal of listed
hazardous wastes is classified as a hazardous waste by virtue of the
``derived-from'' rule in 40 CFR 261.3(c)(2). The Agency has been clear
in the past that hazardous waste listings apply to wastes disposed of
prior to the effective date of a listing, even if the landfill ceases
disposal of the waste when the waste becomes hazardous (see 53 FR
31147; August 17, 1988). We also have a well-established interpretation
that listings likewise apply to leachate derived from the disposal of
listed hazardous wastes, including leachate derived from wastes
disposed before a listing effective date which meet the listing
description. We are not reopening any of these issues by the present
notice.
Of course, as set out in detail in the August 1988 notice, this
does not mean that landfills holding wastes which are subsequently
listed as hazardous become subject to Subtitle C regulation. However,
previously disposed wastes now meeting a listing description, including
residues such as leachate which are derived from such wastes, which are
``actively managed'' do become subject to Subtitle C regulation (id.).
In many, indeed most circumstances, active management of leachate would
be exempt from Subtitle C regulation because the usual management
practice is discharge either to POTWs via the sewer system, where
leachate mixes with domestic sewage and is excluded from RCRA
jurisdiction (see RCRA Section 1004(27) and 40 CFR 261.4(a)(1)), or to
navigable waters, also excluded from RCRA jurisdiction (see RCRA
Section 1004(27) and 40 CFR 261.4(a)(2))
ement of leachate would
be exempt from Subtitle C regulation because the usual management
practice is discharge either to POTWs via the sewer system, where
leachate mixes with domestic sewage and is excluded from RCRA
jurisdiction (see RCRA Section 1004(27) and 40 CFR 261.4(a)(1)), or to
navigable waters, also excluded from RCRA jurisdiction (see RCRA
Section 1004(27) and 40 CFR 261.4(a)(2)). In addition, management of
leachate in wastewater treatment tanks prior to discharge under the CWA
is also exempt from RCRA regulation (40 CFR 264.1(g)(6)).
However, we believe, because the proposed listings for the two
categories of dye and pigment wastes (K167-K168) are concentration-
based listings, it would be difficult to know whether the previously
disposed wastes that meet the narrative description of K167-K168 are in
fact K167-K168 hazardous wastes that exceed the listing levels. We
don't anticipate that records documenting the concentrations of
proposed constituents of concern for these wastes exist for previously
disposed wastes. Therefore, absent a finding that the wastes, when
disposed, would have met the listing being proposed today, the
previously disposed wastes (including landfill leachate and gas
condensate derived from these wastes that are actively managed) could
not be classified as K167-K168.
However, if actively managed landfill leachate and gas condensate
derived from the two categories of dye and pigment wastes proposed to
be listed in today's rule could be classified as K167-K168, we are
concerned about the potential disruption in current leachate management
that could occur and the possibility for redundant regulation.
Recently, this issue was raised to the Agency in the context of the
petroleum refinery waste listings (see 63 FR 42173; August 6, 1998)
the two categories of dye and pigment wastes proposed to
be listed in today's rule could be classified as K167-K168, we are
concerned about the potential disruption in current leachate management
that could occur and the possibility for redundant regulation.
Recently, this issue was raised to the Agency in the context of the
petroleum refinery waste listings (see 63 FR 42173; August 6, 1998). A
commenter expressed concern that, because some of their nonhazardous
waste landfills received petroleum wastes which are now listed, the
leachate that is collected and managed from these landfills would be
classified as hazardous. The commenter argued that this could lead to
increased treatment and disposal costs without necessarily any
environmental benefit. After examining and seeking comment on this
issue, we published a final rule that temporarily defers regulation of
landfill leachate and gas condensate derived from certain listed
petroleum refining wastes (K169-K172) that were disposed before, but
not after, the new listings became effective, provided certain
conditions are met (see 64 FR 6806; February 11, 1999).
At the time this issue was brought to the Agency's attention in the
context of the petroleum refinery waste listings, EPA's Office of Water
had recently proposed national effluent limitations guidelines and
pretreatment standards for wastewater discharges--most notably,
leachate--from certain types of landfills (see 63 FR 6426; February 6,
1998). In support of this proposal, EPA conducted a study of the volume
and chemical composition of wastewaters generated by both Subtitle C
(hazardous waste) and Subtitle D (nonhazardous waste) landfills,
including treatment technologies and management practices currently in
use. EPA proposed effluent limitations (for nine pollutants in the
Nonhazardous Subcategory) for direct dischargers (see 63 FR 6463)
ort of this proposal, EPA conducted a study of the volume
and chemical composition of wastewaters generated by both Subtitle C
(hazardous waste) and Subtitle D (nonhazardous waste) landfills,
including treatment technologies and management practices currently in
use. EPA proposed effluent limitations (for nine pollutants in the
Nonhazardous Subcategory) for direct dischargers (see 63 FR 6463). Most
pertinent to finalizing the temporary deferral for the petroleum
refining wastes, EPA did not propose pretreatment standards for
Subtitle D landfill wastewaters sent to POTWs because the Agency's
information indicated that such standards were not required.
The conditions included in the temporary deferral published on
February 11, 1999 are that the leachate is subject to regulation under
the Clean Water Act, and the leachate is not stored in surface
impoundments after February 13, 2001. See 40 CFR 261.4(b)(15). We
believed that it was appropriate to temporarily defer the application
of the new waste codes to such leachate in order to avoid disruption of
ongoing leachate management activities while the Agency decides how to
integrate the RCRA and CWA regulations consistent with RCRA section
1006(b)(1). As discussed above, we do not anticipate that this
situation is likely to occur because the nature of the concentration-
based listing makes it difficult to determine whether the wastes
previously disposed met the concentrations at the time of disposal.
However, to the extent previously disposed of dye and pigment wastes
could be dete
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