Hazardous Waste Management System: Identification and Listing of Hazardous Waste; Amendment to Hazardous Waste Code F019, 2219-2235 [E7-640]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 72, Number 11 (Thursday, January 18, 2007)]
[Proposed Rules]
[Pages 2219-2235]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-640]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 261 and 302

[EPA-HQ-RCRA-2006-0984, FRL-8270-7]
RIN 2050-AG15


Hazardous Waste Management System: Identification and Listing of 
Hazardous Waste; Amendment to Hazardous Waste Code F019

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
amend today the list of hazardous wastes from non-specific sources 
(called F-wastes) under 40 CFR 261.31 by modifying the scope of the EPA 
Hazardous Waste No. F019 (Wastewater treatment sludges from the 
chemical conversion coating of aluminum except from zirconium 
phosphating in aluminum can washing when such phosphating is an 
exclusive conversion coating process). The Agency would be amending the 
F019 listing to exempt wastewater treatment sludges from zinc 
phosphating, when such phosphating is used in the motor vehicle 
manufacturing process. EPA is proposing two options that would require 
that the wastes be disposed in a landfill unit that meets certain liner 
design criteria. These proposed modifications to the F019 listing would 
not affect any other wastewater treatment sludges either from the 
chemical conversion coating of aluminum, or from other industrial 
sources. Additionally, this action would amend the Comprehensive 
Environmental Response, Compensation, and Liability Act (CERCLA) list 
of Hazardous Substances and Reportable Quantities under 40 CFR 302.4 so 
that the F019 listing description is consistent with the proposed 
amendment to F019 under 40 CFR 261.31.

DATES: Comments must be received on or before March 19, 2007. Under the 
Paperwork Reduction Act, comments on the information collection 
provisions must be received by OMB on or before February 20, 2007.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
RCRA-2006-0984 by one of the following methods:
     www.regulations.gov: Follow the on-line instructions for 
submitting comments.
     E-mail: Comments may be sent by electronic mail (e-mail) 
to rcra.docket@epamail.epa.gov, Attention Docket ID No. EPA-HQ-RCRA-
2006-0984.
     Mail: Comments may be submitted by mail to: OSWER Docket, 
Office of Solid Waste, U.S. Environmental Protection Agency, Mailcode: 
5305T, 1200 Pennsylvania Avenue, NW., Washington, DC 20460, Attention 
Docket ID No. EPA-HQ-RCRA-2006-0984. Please include a total of three 
copies of your comments. In addition, please mail a copy of your 
comments on the information collection provisions to the Office of 
Information and Regulatory Affairs, Office of Management and Budget 
(OMB), Attn: Desk Officer for EPA, 725 17th Street, NW., Washington, DC 
20503.
     Hand Delivery: Deliver your comments to: EPA Docket 
Center, Public Reading Room, Room 3334, EPA West Building, 1301 
Constitution Avenue, NW., Washington, DC 20460, Attention Docket ID No. 
RCRA-2006-0984. Such deliveries are only accepted during the Docket's 
normal hours of operation (8:30 a.m. to 4:30 p.m., Monday through 
Friday, excluding legal holidays) and special arrangements should be 
made for deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-RCRA-
2006-0984. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
www.regulations.gov, including any personal information provided, 
unless the comment includes information claimed to be Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Do not submit information that you consider to 
be CBI or otherwise protected through www.regulations.gov or e-mail. 
The www.regulations.gov Web site is an ``anonymous access'' system, 
which means EPA will not know your identity or contact information 
unless you provide it in the body of your comment. If you send an e-
mail comment directly to EPA without going through www.regulations.gov 
your e-mail address will be automatically captured and included as a 
part of the comment that is placed in the public docket and made 
available on the Internet. If you submit an electronic comment, EPA 
recommends that you include your name and other contact information in 
the body of your comment and with any disk or CD ROM you submit. If EPA 
cannot read your comment due to technical difficulties and cannot 
contact you for clarification, EPA may not be able to consider your 
comment. Electronic files should avoid the use of special characters, 
any form of encryption, and be free of any defects

[[Page 2220]]

or viruses. For additional information about EPA's public docket visit 
the EPA Docket Center homepage at https://www.epa.gov/epahome/
dockets.htm.
    Docket: All documents in the docket are listed in 
www.regulations.gov index. Although listed in the index, some 
information is not publicly available, i.e., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in www.regulations.gov or in hard copy at the OSWER Docket in the EPA 
Docket Center (EPA/DC), EPA West, Room 3334, 1301 Constitution Avenue, 
NW., Washington, DC 20460. The Public Meeting Room is open from 8:30 
a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The 
telephone number for the OSWER Docket and the Public Reading Room is 
(202) 566-1744.

FOR FURTHER INFORMATION CONTACT: Mr. James Michael of the Office of 
Solid Waste (5304W), U.S. Environmental Protection Agency, 1200 
Pennsylvania Avenue, NW., Washington, DC 20460, (E-mail address and 
telephone number: michael.james@epa.gov, (703) 308-8610). For 
information on the procedures for submitting CBI data, contact Ms. 
LaShan Haynes (5305W), U.S. Environmental Protection Agency, 1200 
Pennsylvania Avenue, NW., Washington, DC 20460, (E-mail address and 
telephone number: haynes.lashan@epa.gov, (703) 605-0516).

SUPPLEMENTARY INFORMATION:

I. General Information

A. Who is Potentially Affected by This Proposed Rule?

    This regulation could directly affect businesses that generate 
certain wastes from the manufacturing of motor vehicles in the (1) 
automobile manufacturing industry and (2) light truck/utility vehicle 
manufacturing industry (NAICS codes 336111 and 336112, respectively). 
Other motor vehicle manufacturing industries (e.g., heavy duty truck or 
motor home manufacturing (NAICS code 336120)) are not affected by this 
rule. The wastes affected by this proposed rule are wastewater 
treatment sludges generated from the chemical conversion coating of 
aluminum using a zinc phosphating process and are currently listed as 
EPA Hazardous Waste No. F019 (see 40 CFR 261.31). If the rule is 
promulgated in either of the two ways it is proposed today, these 
wastes would not be hazardous waste, provided the wastes are disposed 
in a landfill unit that meets certain liner design criteria. Impacts on 
potentially affected entities are summarized in Section VI of this 
Preamble. The document, ``Estimate of Potential Economic Impacts for 
USEPA's Proposed Amendment to RCRA Hazardous Wastecode F019 to Exclude 
Motor Vehicle Manufacturing Industries,'' presents an analysis of 
potentially affected entities (hereinafter, referred to as the 
Economics Background Document). This document is available in the 
docket established in support of today's proposed rule. Entities 
potentially affected by this action are at least 14 current generators 
within the motor vehicle manufacturing industry consisting of six auto 
and eight light truck/utility vehicle plants and up to 39 other 
facilities in these two industries that may begin applying aluminum 
parts and could potentially generate F019 waste.
    To determine whether your facility is affected by this action, you 
should examine 40 CFR Parts 260 and 261 carefully, along with the 
proposed regulatory language amending Chapter I of the Code of Federal 
Regulations (CFR). This language is found at the end of this Federal 
Register notice. 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. What Should I Consider as I Prepare My Comments for EPA?

    1. Submitting CBI. Do not submit this information to EPA through 
www.regulations.gov or e-mail. Clearly mark the part or all of the 
information that you claim to be CBI. For CBI information submitted on 
a disk or CD ROM that you mail to EPA, mark the outside of the disk or 
CD ROM as CBI and then identify electronically within the disk or CD 
ROM the specific information that is claimed as CBI. In addition to one 
complete version of the comment that includes information claimed as 
CBI, a copy of the comment that does not contain the information 
claimed as CBI must be submitted for inclusion in the public docket. 
Information so marked will not be disclosed except in accordance with 
the procedures set forth in 40 CFR part 2.
    2. Tips for Preparing your Comments. When submitting comments, 
remember to:
     Identify the rulemaking by docket number and other 
identifying information (subject heading, Federal Register date and 
page number).
     Follow directions--The agency may ask you to respond to 
specific questions or organize comments by referencing a Code of 
Federal Regulations (CFR) part or section number.
     Explain why you agree or disagree; suggest alternative and 
substitute language for your requested changes.
     Describe any assumptions that you used and provide any 
technical information and/or data that you used.
     If you estimate potential burden or costs, explain how you 
arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
     Provide specific examples to illustrate your concerns and 
suggest alternatives.
     Explain your views as clearly as possible, avoiding the 
use of profanity or personal threats.
     Make sure to submit your comments by the comment period 
deadline identified.

Preamble Outline

I. Legal Authority
II. List of Acronyms
III. Overview
    Purpose of This Proposed Rule
IV. Background
    A. How EPA Regulates Hazardous Waste
    B. Overview of the F019 Listing
    C. Regulatory History of F006/F019
    D. Description of the Zinc Phosphating-Conversion Coating 
Process at Motor Vehicle Manufacturing Plants
    E. Amount of F019 Sludge Generated by the Motor Vehicle 
Manufacturing Industry
    F. Composition of the F019 Sludge
    G. How F019 Sludge Is Currently Managed
V. Approach Used in This Proposed Listing Amendment
    A. Concentration-Based Approach vs. Disposal in a Landfill 
Meeting Certain Liner Design Criteria
    B. Overview of the Risk Assessment
    1. EPA's Approach To Assessing Potential Risks to Human Health 
and the Environment
    2. How EPA Chose Constituents of Potential Concern for 
Evaluation
    3. Evaluation of Potential Human Health and Environmental Risks
    4. Uncertainty in the Risk Assessment Results
VI. Implementation of the F019 Proposed Rule
    A. Land Disposal Conditions
    1. How Generators Document Compliance With the Landfill 
Condition
    2. Consequences of Failing To Meet the Disposal Conditions and 
Recordkeeping Requirements
    3. Land Disposal Restrictions
    B. Interrelationships Between Proposed Rule and Current F019 
Delistings
VII. State Authorization
VIII. Comprehensive Environmental Response, Compensation, and 
Liability Act (CERCLA) Designation and List of Hazardous Substances 
and Reportable Quantities
IX. Relationship to Other Rules--Clean Water Act

[[Page 2221]]

X. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect 
Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

I. Legal Authority

    EPA proposes these regulations under the authority of Sections 2002 
and 3001(b) and (f), 3004(d)-(m) and 3007(a) of the Solid Waste 
Disposal Act, as amended by the Resource Conservation and Recovery Act 
(RCRA), as amended, most importantly by the Hazardous and Solid Waste 
Amendments of 1984 (HSWA), 42 U.S.C. 6912, 6921(b), 6924(d)-(m) and 
6927(a). These statutes combined are commonly referred to as the 
``Resource Conservation and Recovery Act'' (RCRA) and will be referred 
to as such for the remainder of this Notice.
    Because EPA is modifying the national listing of F019, EPA believes 
the appropriate statutory authority is that found in section 3001 (b), 
rather than the authority in section 3001 (f). RCRA section 3001 (f) 
pertains solely to the exclusion of a waste generated at a particular 
facility in response to a petition. Accordingly, neither the procedures 
nor the standards established in that provision, or in EPA's 
regulations at 40 CFR 260.22 are applicable to this rulemaking.
    Section 102(a) of the Comprehensive Environmental Response, 
Compensation, and Liability Act of 1980 (CERCLA), 42 U.S.C. 9602(a) is 
the authority under which the CERCLA aspects of this rule are 
promulgated.

II. List of Acronyms

                                Acronyms
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         Acronym                             Definition
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BRS......................  Biennial Reporting System
CBI......................  Confidential Business Information
CERCLA...................  Comprehensive Environmental Response,
                            Compensation, and Liability Act
CFR......................  Code of Federal Regulations
COPCs....................  Constituents of Potential Concern
CWA......................  Clean Water Act
DAF......................  Dilution and Attenuation Factor
DRAS.....................  Delisting Risk Assessment Software
EPA......................  Environmental Protection Agency
ICR......................  Information Collection Request
IWEM.....................  Industrial Waste Management Evaluation Model
LDR......................  Land Disposal Restrictions
MCL......................  Maximum Contamination Limit
NAICS....................  North American Industrial Classification
                            System
NTTAA....................  National Technology and Transfer Act
OMB......................  Office of Management and Budget
OSWER....................  Office of Solid Waste and Emergency Response
PRA......................  Paperwork Reduction Act
POTW.....................  Publicly Owned Treatment Works ppm parts per
                            million
RCRA.....................  Resource Conservation and Recovery Act
RFA......................  Regulatory Flexibility Act
RQ.......................  Reportable Quantity
SIC......................  Standard Industrial Classification
TRI......................  Toxics Release Inventory
UMRA.....................  Unfunded Mandates Reform Act
WWT......................  Wastewater Treatment
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III. Overview

 Purpose of the Proposed Rule

    The Agency is proposing to amend the list of hazardous wastes from 
non-specific sources under 40 CFR 261.31 by modifying the scope of EPA 
Hazardous Waste No. F019, which currently reads: ``Wastewater treatment 
sludges from the chemical conversion coating of aluminum except from 
zirconium phosphating in aluminum can washing when such phosphating is 
an exclusive conversion coating process.'' The Agency is proposing to 
amend the F019 listing to exempt the wastewater treatment sludge 
generated from zinc phosphating, when zinc phosphating is used in the 
automobile assembly process and provided the waste is disposed in a 
landfill unit subject to certain liner design criteria. Specifically, 
under the two options proposed today, these wastes would not be 
hazardous if they are disposed in a landfill unit subject to, or 
otherwise meeting, certain liner requirements. Wastes that meet this 
condition would be exempted from the listing from their point of 
generation, and would not be subject to any RCRA Subtitle C management 
requirements for generation, storage, transport, treatment, or disposal 
(including the land disposal restrictions). Generators of such wastes 
may be exempted from the F019 listing if they meet the condition for 
exemption, and they maintain adequate records. EPA is proposing to 
require generators to keep records showing that they used a landfill 
that meets the design requirements.
    The motor vehicle manufacturing industry incorporates aluminum into 
vehicle parts and bodies for the purpose of making them lighter-weight 
and thus more capable of increasing gas mileage. However, when aluminum 
is incorporated into the body of an automobile, the conversion coating 
step in the manufacturing process results in the generation of a RCRA-
listed hazardous waste (F019) in the form of a wastewater treatment 
sludge from the

[[Page 2222]]

conversion coating process, while the wastewaters from the conversion 
coating of steel in the same industry do not generate a listed 
hazardous waste. By removing the regulatory controls under RCRA, EPA is 
facilitating the use of aluminum in motor vehicles. The Agency believes 
that the incorporation of aluminum will be advantageous to the 
environment since lighter-weight vehicles are capable of achieving 
increased fuel economy and associated decreased exhaust air emissions.

IV. Background

A. How EPA Regulates Hazardous Waste

    EPA's regulations establish two ways of identifying solid wastes as 
hazardous under RCRA. A waste may be considered hazardous if it 
exhibits certain hazardous properties (``characteristics'') or if it is 
included on a specific list of wastes EPA has determined are hazardous 
(``listing'' a waste as hazardous) because the Agency found them to 
pose substantial present or potential hazards to human health or the 
environment. EPA's regulations in the Code of Federal Regulations (40 
CFR) define four hazardous waste characteristic properties: 
ignitability, corrosivity, reactivity, and toxicity (see 40 CFR 261.21-
261.24). As a generator, you must determine whether or not a waste 
exhibits any of these characteristics by testing, or by using your 
knowledge of the process that produced the waste (see Sec.  262.11(c)).
    EPA may also conduct a more specific assessment of a waste or 
category of wastes and ``list'' them if they meet criteria set out in 
40 CFR 261.11. Under the third criterion, identified in 40 CFR 261.11 
(a)(3), the Agency may list a waste as hazardous if it contains 
hazardous constituents identified in 40 CFR part 261, Appendix VIII, 
and if EPA concludes that ``the waste is capable of posing a 
substantial present or potential hazard to human health or the 
environment when improperly treated, stored, transported, or disposed 
of, or otherwise managed.'' EPA places chemicals on the list of 
hazardous constituents in 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 40 CFR 
261.11(a)(3). When listing a waste, the Agency also adds any hazardous 
constituents that serve as the basis for listing the waste to 40 CFR 
part 261, Appendix VII.
    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 
waste generated from non-specific sources, known as ``F-wastes,'' and 
contain wastes that are usually generated by various industries or 
types of facilities. Today's proposed regulations would revise the 
listing for one of these wastes, F019.
    If a waste exhibits a hazardous characteristic, or is listed as a 
hazardous waste, then it is subject to federal requirements under RCRA. 
Facilities that generate, transport, treat, store or dispose of such 
waste must meet hazardous waste management requirements, including the 
need to obtain permits to operate, are commonly referred to as 
``Subtitle C'' facilities. (Subtitle C is the subsection of RCRA that 
governs the management of hazardous waste. EPA standards and procedural 
regulations implementing Subtitle C are found generally at 40 CFR parts 
260 through 273.)
    The RCRA regulations provide a form of relief for listed wastes 
through a site-specific process known as ``delisting.'' The regulations 
governing the delisting process are given at 40 CFR 260.20 and 260.22. 
These regulations set out a procedure and standards by which persons 
may demonstrate that a specific waste from a particular generating 
facility should not be regulated as a listed hazardous waste under 
Subtitle C of RCRA. Under these regulations, any person may petition 
EPA to remove its waste from regulation by excluding it from the lists 
of hazardous wastes contained in Part 261. EPA has granted delistings 
to various facilities that generate or manage F019 wastes, including 
motor vehicle manufacturing plants. (See Section IV.D.) As a condition 
to some of the granted delistings, the facility generating that waste 
must periodically sample and analyze the waste for the presence and 
quantity of specific chemical constituents of concern. This periodic 
sampling and analysis is called ``verification sampling.'' In some 
cases, facilities submit the results of the verification sampling and 
analysis to EPA to ensure that the waste's continuing status of 
nonhazardous is appropriate.
    A solid waste, that is determined not to be a listed and/or 
characteristic hazardous waste, may be managed at ``Subtitle D'' 
facilities. These facilities are approved by state and local 
governments and generally impose less stringent requirements on 
management of wastes than Subtitle C facilities. Subtitle D is the 
statutory designation for that part of RCRA that deals with disposal of 
nonhazardous solid waste. EPA regulations affecting Subtitle D 
facilities are found at 40 CFR parts 240 through 247, and 255 through 
258. Regulations for Subtitle D landfills that accept municipal waste 
(``municipal solid waste landfills'') are in 40 CFR part 258.

B. Overview of F019 Listing

    Hazardous Waste No. F019 is defined as ``Wastewater treatment 
sludges from the chemical conversion coating of aluminum except from 
zirconium phosphating in aluminum can washing when such phosphating is 
an exclusive conversion coating process.'' The hazardous constituents 
for which the waste is listed are hexavalent chromium and cyanide 
(complexed). The F019 wastewater treatment sludge is generated from the 
rinses and overflows from the chemical conversion coating of aluminum. 
Chemical conversion coating processes involve the application of a 
coating to a previously deposited metal or a base metal for increased 
corrosion protection, lubricity, preparation of the surface for 
additional coatings, or formulation of a special surface appearance. 
This manufacturing operation includes chromating, phosphating, metal 
coloring and immersion plating.
    Phosphate conversion coatings produce a mildly protective layer of 
insoluble crystalline phosphate on the surface of a metal. Phosphate 
coatings are used to provide a more suitable base for paints and other 
inorganic coatings, to condition the surfaces for cold forming 
operations by providing a base for drawing compounds and lubricants, 
and to impart corrosion resistance to the metal surface by the coating 
itself or by providing a suitable base for rust-preventive oils or 
waxes. Phosphate conversion coatings are formed by the immersion of 
iron, steel or zinc plated steel in a dilute solution of phosphoric 
acid plus other reagents. Phosphate conversion coatings can also 
involve spray-on applications.

C. Regulatory History of F006/F019

    On May 19, 1980, EPA published an interim final rule listing 
``wastewater treatment sludges from electroplating operations'' as EPA 
Hazardous Waste No. F006. See 40 CFR 261.31 (45 FR 33112). The 
hazardous constituents for which this waste was listed are cadmium, 
hexavalent chromium, nickel and complexed cyanide. In response to 
comments on the interim final regulation, the listing was modified on 
November 12, 1980 (45 FR 74884) to read as follows: ``wastewater 
treatment sludges from electroplating operations except from the 
following processes: (1) Sulfuric acid anodizing of aluminum; (2) tin 
plating on carbon steel; (3) zinc

[[Page 2223]]

plating (segregated basis) on carbon steel; (4) aluminum or zinc-
aluminum plating on carbon steel; (5) cleaning/stripping associated 
with tin, zinc and aluminum plating on carbon steel; and, (6) chemical 
etching and milling of aluminum.''
    Additionally, in response to other comments, the Agency separated 
``wastewater treatment sludges from the chemical conversion coating of 
aluminum'' from the F006 listing and listed them as F019. Commenters 
had argued that these sludges should not be listed as F006 because they 
do not contain all four of the constituents for which F006 was listed. 
That is, commenters contended that these wastes do not typically 
contain cadmium and nickel. EPA agreed that these wastes did not 
typically contain cadmium and nickel, but maintained that, since the 
wastes contain hexavalent chromium and complexed cyanides, they should 
nevertheless be regulated. The Agency, therefore, listed them as 
hazardous waste, F019, and only listed hexavalent chromium and 
complexed cyanides as the constituents of concern for these wastes in 
Appendix VII of Part 261.\1\
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    \1\ Note that aluminum conversion coating using the zinc 
phosphating process utilizes nickel, as noted in section IV.D.; 
thus, nickel is a potential constituent of concern in the waste at 
issue in this proposed amendment.
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    On December 2, 1986 (51 FR 43350), EPA issued an interpretive rule 
stating that the Agency had re-evaluated its previous interpretations 
of the scope of the application of F006 and had determined that those 
interpretations were overly broad. As a result, the Agency stated that 
the following processes were not included in the F006 listing: chemical 
conversion coating, electroless plating and printed circuit board 
manufacturing. EPA further clarified that the F006 listing includes 
wastewater treatment sludges from: (1) Common and precious metals 
electroplating, except tin, zinc (segregated basis), aluminum and zinc 
plating on carbon steel; (2) anodizing, except sulfuric acid anodizing 
of aluminum; (3) chemical etching and milling, except when performed on 
aluminum; and, (4) cleaning and stripping, except when associated with 
tin, zinc, and aluminum plating on carbon steel. While this 
interpretation removed chemical conversion coating from the scope of 
F006, it did not affect the F019 listing. That is, wastewater treatment 
sludges from the chemical conversion coating of aluminum continued to 
be regulated as F019.
    Through a number of delistings and the Agency's evaluation for 
today's proposal, EPA has since learned that one of the chemical 
conversion coating operations--zinc phosphating--may not result in the 
generation of a hazardous wastewater treatment sludge. (See discussion 
below describing the zinc phosphating process.) Therefore, EPA is 
proposing today to amend the F019 listing to exempt the wastewater 
treatment sludges from zinc phosphating, when such phosphating is used 
at motor vehicle manufacturing plants, provided certain disposal 
conditions are met.
    EPA is not reopening any aspect of the F019 listing other than 
those specifically identified in this proposal, and will not respond to 
any comments that address issues beyond the specific proposals outlined 
in this notice.

D. Description of the Zinc Phosphating-Conversion Coating Process at 
Motor Vehicle Manufacturing Plants

    The zinc phosphating process at motor vehicle manufacturing plants 
is a multiple stage immersion process. The number of stages in the zinc 
phosphating process may vary from plant to plant, but they generally 
involve: cleaning and surface preparation, rinsing, conversion coating 
and rinsing.
    Cleaning and surface preparation: The purpose of this stage is to 
remove the physical contaminants from the surface of the assembled 
vehicle body so that the conversion coating will be applied evenly and 
continuously across the metal surfaces. Typical surface contaminants 
are metal working oil, rust protection oil, dirt and oxides from 
corrosion. Since the surface of the metal becomes part of the coating, 
this stage is particularly important. Improper processing can result in 
blisters or poor appearance in the metal finish. Cleaning and surface 
preparation is typically done first with water and surfactants followed 
by an alkaline solution. The alkaline solution removes microscopic 
layers of metal to ensure that metal is exposed and available for the 
chemical conversion reactions.
    Rinsing: The rinse stage stops the metal removal by washing away 
the alkaline solution. Rinsing is done with water followed by an 
alkaline rinse conditioner, which prepares the metal surface for the 
conversion coating process.
    Conversion coating: During this stage, the conversion coating 
process converts the metal surface of the assembled vehicle bodies by 
dissolving the metal and forming ``sites'' into which the zinc 
phosphate coating is deposited. The zinc phosphate coating provides a 
stable, corrosion resistant base for painting. The phosphated 
conversion coating bath contains phosphoric acid with certain metals 
(zinc and manganese) and accelerators such as nickel. Fluoride is added 
to control crystal structure and maintain the composition of the bath. 
Hexavalent chromium and complexed cyanides are not used in this zinc 
phosphating conversion coating process.\2\
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    \2\ The analytical data for sludge samples show the presence of 
chromium and cyanide. Chromium appears to arise, in part, from the 
use of trivalent chromium in ``sealing'' during the rinsing step in 
the process; the source of trace levels of cyanide is not clear. 
However, levels of hexavalent chromium and cyanide were not present 
at levels of concern based on EPA's risk assessment (i.e., the 
``Technical Support Document: Assessment of Potential Risks from 
Managing F019 Waste from Motor Vehicle Manufacturing Industry'' in 
the docket for this proposed rulemaking); also see Section V.B.
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    Rinsing: Once the conversion coating process is completed, the 
assembled vehicle bodies go through a water rinse to stop the 
conversion coating process and to remove any excess salts from the 
metal surfaces. A final acidic rinse is then used to seal the pores in 
the zinc phopshate coating and to remove any excess materials from the 
metal surfaces. During this final rinse, a sealant is added for 
additional corrosion protection. From here, the assembled vehicle 
bodies then proceed to the painting process.

E. Amount of F019 Sludge Generated by the Motor Vehicle Manufacturing 
Industry

    As of 2003, 11 automobile manufacturing plants (NAICS 336111) 
generated a total of 5,300 tons per year of F019 sludge ranging between 
177 and 1,249 tons per year per plant (average of 477 tons per year per 
plant), and 12 light truck/utility vehicle manufacturing plants (NAICS 
336112) generated a total of 9,300 tons per year of F019 sludge ranging 
between 112 to 1,620 tons per year per plant (average of 772 tons per 
year per plant). As of year-end 2005, EPA regional offices have 
delisted 47 former F019 generators in 19 industries, including 35,000 
cubic yards (i.e., about 35,000 tons) per year of F019 sludge formerly 
generated by 15 motor vehicle manufacturing plants. Historically, 
between 1995 and 2003, the annual count of F019 generators in the motor 
vehicle manufacturing industries affected by this proposed rule has 
fluctuated between 10 to 22 generators, and between 8,000 to 13,000 
tons per year of F019 sludge generated.

F. Composition of the F019 Sludge

    The F019 sludge from motor vehicle manufacturers is generated from 
dewatering of wastewater, typically

[[Page 2224]]

yielding a pressed ``filter cake'' with a solids content that ranges 
between 30% and 50% by weight. Reviewing the Material Safety Data 
Sheets for the chemicals used in, and prior to, the conversion coating 
process indicates that a wide range of elements can be expected to be 
present in the wastewaters and the sludges resulting from wastewater 
treatment.
    The specific chemical constituents that are found in motor vehicle 
manufacturers' F019 sludge, listed in order of frequency found, are 
nickel, fluoride, zinc, barium, copper and chromium (all found in 100% 
of a selected number of samples reviewed); tin, formaldehyde, lead, 
cobalt, mercury, sulfide and xylenes (found in 70-99% of a selected 
number of samples reviewed); acrylamide, vanadium, arsenic, cyanide, 
hexavalent chromium, and ethylbenzene (found in 50-69% of a selected 
number of samples reviewed).

G. How F019 Sludge Is Currently Managed

    According to data from the 2003 RCRA Hazardous Waste Biennial 
Report (https://www.epa.gov/enviro/html/brs/brs_query.html), F019 
sludges generated by motor vehicle manufacturers are disposed in RCRA 
Subtitle C regulated facilities, after de-watering, stabilization and/
or other treatment. Although two of the 17 generators in the motor 
vehicle manufacturing industry reportedly disposed their F019 sludges 
onsite (about 300 tons/year), all of the 22 automobile and light truck/
utility vehicle manufacturing plants in 2003 reported managing F019 
sludges offsite at RCRA Subtitle C regulated landfills in six states 
(IL, LA, MI, OK, PA, and SC), located at transport distances of 19 to 
1,500 miles (average 400 miles).
    EPA recognizes that several recent rulemakings related to RCRA-
listed hazardous wastes have proposed conditional exemptions from the 
regulatory definition of ``solid waste'' when such wastes, by virtue of 
their being recycled, are treated more as commodities than as wastes. 
For example, see 68 FR 61588, October 28, 2005. The Agency is not aware 
of any recycling or reclamation of F019 sludges; therefore, EPA 
believes that current market conditions do not support the recycling of 
F019 waste for the purposes of recovering the metal content of such 
waste. EPA requests comment on whether our understanding is accurate 
and whether recycling of F019 waste is economically feasible under 
today's market conditions. If recycling of F019 wastes becomes 
economically feasible or beneficial in the future, the Agency will 
consider its options for how to address this, including through a 
subsequent rulemaking, such as the ongoing rulemaking related to the 
definition of solid waste.

V. Approach Used in This Proposed Listing Amendment

A. Concentration-Based Approach vs. Disposal in a Landfill Meeting 
Certain Liner Design Criteria

    On April 22, 2005, EPA, through a posting on EPA's website, 
indicated that the Agency was in the process of considering a possible 
amendment to the F019 hazardous waste listing under RCRA. This possible 
amendment would have exempted waste water treatment sludges from the 
zinc phosphating processes at automotive assembly plants in the motor 
vehicle manufacturing industry when concentrations of constituents of 
concern in those wastes fell below risk-based exemption levels. On the 
F019 Web page, EPA provided waste sampling data and the methodology 
that the Agency would use in considering the revision of the F019 
listing using a concentration-based approach. Interested parties were 
invited to review and comment on the information collected to support 
the possible amendment that EPA was considering. The comment period for 
the web posting closed on June 1, 2005. Twelve comments were received. 
All commenters supported a revision to the F019 listing, although some 
expressed concern regarding testing conditions for potential chemicals 
of concern in the waste and how the concentration-based exemption would 
be structured. Copies of these comments are included in the docket for 
today's proposed rulemaking.
    Below in Section V. B., EPA presents a detailed discussion of the 
Agency's approach in assessing the potential risks to human health and 
the environment and how EPA chose the potential constituents of concern 
that could be used in the concentration-based approach. However, as the 
Agency conducted the risk analysis and developed the implementation 
schemes to go with this approach, several issues arose. First, a 
variety of issues arose related to establishing precise exemption 
concentrations for the waste, including: the amount of waste ultimately 
disposed in the modeled landfill (which is dependent on annual volume 
and years of disposal); which toxicity benchmarks to use (e.g., 
drinking water standards or other health-based values); and exposure 
assumptions built into the Delisting Risk Assessment Software (DRAS) 
model (e.g., groundwater consumption for different age groups). (See 
Section V. B. for a more detailed discussion on the documentation of 
the DRAS model.)
    Second, in order to accommodate the wide range in the volumes of 
F019 wastewater treatment sludges generated at the different automotive 
assembly plants, the Agency would need to develop different exemption 
levels for each of the constituents of concern for the various annual 
waste volumes (e.g., 500 cubic yards to 5000 cubic yards per year at 
500 cubic yard intervals). In order to ensure compliance with the 
concentration-based approach, the automotive assembly plants would need 
to maintain detailed records on the amount of waste generated and 
implement a representative sampling and analysis program to ensure that 
they met the exemption levels for the volume of waste each facility 
generated annually. Furthermore, two constituents were identified that 
presented potential risks to human health (arsenic and nickel) in an 
unlined landfill scenario as modeled by DRAS version 2. Rather than 
attempt to define precise exemption levels for constituents of concern, 
the Agency believes that it is simpler to require disposal in a 
landfill that is subject to certain liner design requirements. The 
Agency is proposing two options for the liner design requirements. 
Under option one, EPA is proposing that the landfill unit meet the 
liner requirements for municipal landfills in 40 CFR 258.40 or other 
liner designs containing a composite liner.\3\ Under option two, the 
Agency is proposing to allow disposal in state-permitted municipal 
solid waste landfills (subject to regulations in 40 CFR 258) and state-
permitted industrial solid waste landfills (subject to Federal 
regulations at 40 CFR 257), provided the landfill unit includes at 
least a single clay liner,\4\ and also in permitted hazardous waste 
landfills. This second option could ease implementation,

[[Page 2225]]

because the generator could rely on the state permitting agency to 
assure proper liner design. The Agency is seeking comment on this 
second approach, because the modeling results indicate that units with 
a less stringent liner design may also reduce the risk from the 
hazardous constituents of concern to acceptable levels.
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    \3\ As noted in Section V.B. below, the Federal regulations for 
municipal solid waste landfills require that new units (and lateral 
expansions of existing units) meet design criteria for composite 
liners and leachate collection systems (or other approved 
performance standards). A composite liner as defined in Sec.  258.40 
consists of a combination of a synthetic liner and an underlying 
compacted soil/clay liner. Disposal in hazardous waste landfills 
would also be allowed, because the regulations in Sec.  264.301 and 
Sec.  265.301 include composite liners.
    \4\ For this option, EPA assumes that single clay liners, even 
in older landfills, would meet the typical construction standards, 
i.e., the clay liner would have a low hydraulic conductivity (i.e., 
1 x 10-7 cm/sec) and be of sufficient thickness to ensure 
structural stability (i.e., 2 to 3 feet of compacted clay). EPA 
seeks comment on this assumption.
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    As discussed further below, EPA found that disposal of the waste 
under evaluation in such lined landfills would ensure protection of 
human health and the environment, without the need for testing and 
tracking of waste volume. EPA believes that the proposed approaches 
outlined in today's notice would be easier and less costly to implement 
than the concentration-based approach, but provides at least the same 
level of protection for human health and the environment.

B. Overview of the Risk Assessment

1. EPA's Approach To Assessing Potential Risks to Human Health and the 
Environment
    Today's action addresses a specific type of industrial sludge: 
sludge generated from the management of wastewaters generated at motor 
vehicle manufacturing (assembly) facilities. In general, industrial 
wastewater treatment sludges consist of suspended solids removed from 
wastewaters during treatment, which may involve various steps. As 
described in one delisting petition, for example, the treatment steps 
include: grit separation, pH adjustment to remove metals, addition of a 
coagulant, clarification to generate a dilute sludge, and dewatering of 
the sludge and grit solids via filter presses.\5\
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    \5\ See General Motors Corporation Oklahoma City Assembly Plant 
Delisting Petition for F019 Wastewater Treatment Plant Sludge Filter 
Cake, Section 3, Facility Operations in the docket.
---------------------------------------------------------------------------

    F019 sludges generated by the motor vehicle manufacturing 
industries are currently managed by onsite dewatering, followed by 
truck or rail shipment to offsite RCRA-permitted hazardous waste 
landfills. Because today's action proposes to allow disposal of the 
wastewater treatment sludge in landfills subject to, or meeting, 
certain design criteria, the Agency's risk assessment involved 
evaluating risks to human health and the environment from this landfill 
disposal scenario. (See the ``Technical Support Document: Assessment of 
Potential Risks from Managing F019 Waste from the Motor Vehicle 
Manufacturing Industry'' in the docket for this proposed rulemaking for 
a detailed description of the analysis that the Agency performed, 
hereinafter, referred to as the Technical Support Document.) EPA 
initially evaluated the potential risks posed by a hypothetical annual 
quantity of F019 waste that is disposed of in an unlined nonhazardous 
waste landfill, and then evaluated potential risks from disposal in 
landfills that use different liner technologies. The human health and 
environmental risk evaluation uses several environmental fate, 
transport, and exposure/risk models: Delisting Risk Assessment Software 
(DRAS), version 2.0,\6\ Tier 1 of the Industrial Waste Management 
Evaluation Model (IWEM),\7\ and EPA's Composite Model for Leachate 
Migration with Transformation Products (EPACMTP).\8\ These models have 
all been peer reviewed; see the Technical Support Document for a 
detailed description of the use of these models and their peer review.
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    \6\ ``RCRA Delisting Technical Support Document''. EPA906-D-98-
001. Interim Final. U.S. Environmental Protection Agency, Office of 
Solid Waste and Emergency Response, Office of Solid Waste. Prepared 
by U.S. Environmental Protection Agency, Region 6, Dallas, TX April 
2002.
    \7\ ``Industrial Waste Management Evaluation Model (IWEM) User's 
Guide.'' EPA530-R-02-013. U.S. Environmental Protection Agency, 
Office of Solid Waste and Emergency Response, Office of Solid Waste. 
Washington, D.C. August 2002, and ``Industrial Waste Management 
Evaluation Model (IWEM) Technical Background Document.'' EPA530-R-
02-012. U.S. Environmental Protection Agency, Office of Solid Waste 
and Emergency Response, Office of Solid Waste. Washington, DC August 
2002.
    \8\ ``EPA's Composite Model for Leachate Migration with 
Transformation Products EPACMTP: User's Guide.'' U.S. Environmental 
Protection Agency, Office of Solid Waste and Emergency Response, 
Office of Solid Waste. Washington, DC 1997, ``EPA's Composite Model 
for Leachate Migration with Transformation Products (EPACMTP) 
Technical Background Document.'' EPA530-R-03-006. U.S. Environmental 
Protection Agency, Office of Solid Waste and Emergency Response, 
Office of Solid Waste. Washington, DC April 2003, and ``EPA's 
Composite Model for Leachate Migration with Transformation Products 
(EPACMTP) Parameters/Data Background Document''. EPA530-R-03-003. 
U.S. Environmental Protection Agency, Office of Solid Waste and 
Emergency Response, Office of Solid Waste. Washington, DC April 
2003.
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    EPA's Regional Offices, and certain states, use version 2.0 of the 
DRAS model, or earlier versions of it, to determine whether to grant 
requests for delistings under 40 CFR 260.22. The DRAS model is a 
screening tool that contains several assumptions that are designed to 
be protective of public health. In addition, EPA then adjusted the DRAS 
model results to take into account exposures to children. The DRAS 
model assesses human health considerations, by assuming that 
populations that live near the landfill (nearby residents) may be 
exposed to chemical constituents that are released from the waste that 
is placed in the landfill. EPA used the DRAS model to calculate the 
levels of chemical constituents in a waste (waste concentrations) that 
would not exceed the acceptable levels at the nearby receptor. The 
acceptable levels are based on the target risks the Agency used in its 
evaluation. For carcinogens, EPA used an increased probability of 
developing cancer that is less than or equal to one in one hundred 
thousand (1 x 10-5). For non-carcinogens, EPA used a 
``hazard quotient'' less than or equal to 1.0; the hazard quotient is 
the ratio of an individual's chronic daily exposure to a standard, such 
as the chronic reference dose. (The reference dose is ``an estimate 
(with uncertainty spanning perhaps an order of magnitude) of a daily 
oral exposure for a chronic duration (up to a lifetime) to the human 
population (including sensitive subpopulations) that is likely to be 
without an appreciable risk of deleterious effects during a 
lifetime.'') \9\ These target risk levels are consistent with those 
discussed in EPA's hazardous waste listing determination policy (see 
the discussion in a proposed listing for wastes from the dye and 
pigment industries, December 22, 1994 (59 FR 66072)).
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    \9\ See EPA's Integrated Risk Information System (IRIS) at 
https://www.epa.gov/iris/.
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    The DRAS model assesses environmental risk by examining the aquatic 
organisms in a body of surface water downhill from the landfill 
(ecological receptors) that are exposed to small quantities of chemical 
constituents that are released from the waste in the landfill. As with 
the human health considerations, the Agency can assess an acceptable 
risk level for those aquatic organisms, such that the sustainability of 
the organisms' population in the surface water body is not compromised. 
The DRAS model then calculates the levels of chemical constituents in 
waste placed in the landfill (i.e., waste concentrations) that should 
not be exceeded in order to have acceptable levels of these 
constituents in the nearby body of surface water.
    For a landfill disposal scenario, the DRAS model predicts how 
constituents of potential concern, or COPCs, will move through the 
environment and affect nearby people or aquatic organisms. The DRAS 
model predicts releases of COPCs from the waste into the groundwater 
beneath the landfill, then accounts for human exposure from drinking 
contaminated groundwater, inhaling volatile constituents when using 
contaminated groundwater for showering, and dermal contact from bathing 
with contaminated groundwater. The DRAS model also

[[Page 2226]]

predicts releases of COPCs from the waste (both waste particles and 
volatile emissions) into the air above the landfill. DRAS then accounts 
for inhalation of volatile constituents and particles, and for 
windblown particles landing on soil and a child ingesting the 
contaminated soil. Finally, the DRAS model predicts releases of COPCs 
from the waste, due to storm water that erodes waste from an open 
landfill and runs off into a nearby body of surface water. Then the 
DRAS model takes into account human exposure from eating fish and 
drinking contaminated surface water, and for the exposures of the fish 
to contaminated surface water. In addition, EPA adjusted the DRAS model 
results to take into account exposures to children. See the Technical 
Support Document for a complete description of the scenario that is 
modeled in DRAS version 2.0, the human health and ecological exposure 
pathways, and the data sources the Agency used as model inputs. The 
DRAS version 2.0 technical documentation, ``User's Guide for the EPA 
Region 6 Delisting Risk Assessment Software'' (EPA906-D-98-001) and the 
``Delisting Technical Support Document,'' which is distributed as part 
of the DRAS modeling software, provides further details about the 
specific assumptions and the mathematical equations that the model 
uses. These documents are in the docket.
2. How EPA Chose Constituents of Potential Concern for Evaluation
    Section IV. F. describes briefly the constituents likely to be 
present in motor vehicle manufacturers' F019 waste. To identify 
constituents of potential concern, EPA reviewed information from 13 
motor vehicle manufacturing facilities' delisting petitions.\10\ This 
information included material safety data sheets (MSDS's) that identify 
the specific chemicals used in the conversion coating process; these 
chemicals are likely to be present in the wastewater that is treated 
and from which F019 sludge results.
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    \10\ The 13 motor vehicle manufacturing facilities are BMWMC 
(BMW Manufacturing Corp.), located in Greer, South Carolina; Nissan, 
in Smyrna, Tennessee; General Motors (GM) in Lansing, Michigan; GM 
in Lake Orion, Michigan; GM in Oklahoma City, Oklahoma (draft 
petition submitted and available only in the EPA Headquarters docket 
for today's notice); GM in Lordstown, Ohio; GM in Pontiac, Michigan; 
GM in Hamtramck, Michigan; GM in Flint, Michigan; GM Grand River in 
Lansing, Michigan; Ford in Wixom, Michigan; Ford in Wayne, Michigan; 
and DaimlerChrysler Jefferson North in Detroit, Michigan.
---------------------------------------------------------------------------

    EPA also compiled the analytical data received from the 13 
facilities' delisting petitions (and from verification sampling at 
several facilities) into a spreadsheet that is available in the docket 
for this rulemaking. These 13 facilities analyzed F019 sludge samples 
for approximately 240 chemical constituents. Many chemicals were not 
found in the F019 sludge at the detection limits used. If these ``non-
detect'' chemicals were not mentioned on the material safety data 
sheets, then EPA did not evaluate these constituents further. For 
example, petitioners analyzed sludge samples for pesticides, such as 2-
sec-butyl-4,6-dinitrophenol (Dinoseb); however, these were not found in 
the MSDS's or in the sludge samples, nor would one expect to find them 
in a motor vehicle manufacturing facility's wastewater treatment 
sludge.
    Of the constituents analyzed in the F019 wastes, 56 were detected 
in one or more samples. EPA evaluated the concentrations reported by 
the petitioners for these 56 chemicals (including concentrations that 
laboratories reported as estimates). The Agency used the DRAS model 
methodology to evaluate potential risks for 55 detected constituents 
for human health risks and 49 for environmental risks.\11\
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    \11\ For human health, one constituent, sulfide, was not 
evaluated using the DRAS methodology because it lacks an appropriate 
toxicity value. For ecological risk, two constituents, sulfide and 
fluoride, were not evaluated using the DRAS methodology because they 
are not present in the DRAS version 2 data base for constituents, 
and lack appropriate toxicity values for environmental risks. For 
another five of the 56 constituents, EPA lacked appropriate aquatic 
toxicity benchmarks to complete an environmental risk assessment. 
See the Technical Support Document in the docket for this proposed 
rulemaking for details.
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3. Evaluation of Potential Human Health and Environmental Risks
    For both human health and environmental risk evaluations, EPA's 
analysis assumed the disposal of a total waste volume of 90,000 cubic 
yards of F019 into a landfill. This waste volume corresponds to either 
a 4,500 cubic yards per year disposal rate for 20 years, or a 3,000 
cubic yards per year disposal rate for 30 years. EPA believes it is 
quite unlikely that motor vehicle manufacturers would dispose of 
amounts greater than 90,000 cubic yards for an extended period of time 
in the same landfill based on a review of the delisting facilities' 
stated annual F019 sludge production quantities. EPA examined the 
information contained in the delisting petitions submitted and more 
recent data provided by facilities in the motor vehicle manufacturing 
industry. Combining the data from both sources for past generation of 
this waste, EPA found that the volumes of sludges disposed ranged from 
426 to 3,892 cy/yr (median was 1,088 cy/yr, and the 90th percentile 
ranked value was approximately 2,900 cy/yr). Therefore, the use of 
3,000 cubic yards per year or 4,500 cubic yards per year represents a 
protective upper-bound for the waste volumes reported by the generators 
and is likely to overestimate volumes currently produced by the 
automotive industry. A number of the constituents detected in the waste 
appear to be present at levels that may be of concern from a human 
health viewpoint. (None of the constituents that EPA evaluated for 
potential environmental harm appeared to be present at levels of 
concern.) When using the maximum detected concentrations and a total 
volume of 90,000 cubic yards disposed in a landfill, the DRAS modeling 
indicated that two of the 55 waste constituents evaluated for human 
health effects showed an estimated hazard quotient greater than 1, or 
showed an individual's estimated lifetime potential excess cancer risk 
to be greater than one in one hundred thousand.
    Based on the assessment using DRAS, the Agency determined that only 
two constituents (arsenic and nickel) had maximum detected values that 
exceeded the levels that DRAS modeling indicated would result in an 
acceptable exposure level. (The other constituents had estimated hazard 
quotients less than 1 and estimated individual lifetime excess cancer 
risk of less than one in one hundred thousand.) For nickel in 
groundwater used as drinking water, the estimated hazard quotient was 
three. For arsenic in groundwater used as drinking water, the estimated 
individual excess lifetime cancer risk was three in one hundred 
thousand. Thus, using protective exposure assumptions, the Agency found 
that disposing of a total of 90,000 cubic yards of waste (equivalent to 
3,000 cubic yards disposed per year for 30 years) containing these two 
constituents, at their maximum detected concentrations in an unlined 
landfill, exceeded the DRAS limit by up to a factor of 3. The Technical 
Support Document describes the DRAS modeling and results, with 
discussion and conclusions, in considerably greater detail.
    As described above, two constituents (arsenic and nickel) were at 
levels that may be of concern using upper-bound assumptions for waste 
quantities disposed and constituent concentrations in unlined 
landfills. Furthermore, the constituents were reported to be prevalent 
in the waste samples. Therefore, EPA examined the robustness of one of 
the key assumptions of the DRAS version 2.0 modeling--modeling

[[Page 2227]]

disposal in a landfill without a liner. Within the past 15 years, 
changes to landfill requirements in the United States (the promulgation 
of federal regulations that require municipal solid waste landfills to 
meet certain leakage prevention requirements, and requirements for 
collecting and managing landfill gases, e.g., see 40 CFR 258.40) have 
caused substantial changes in landfill practices. The majority of 
municipal solid waste landfills, and probably many landfills that 
accept nonhazardous industrial solid waste but not municipal solid 
waste, now are designed, built, and operated with liner systems that 
typically include composite liners and leachate collection systems (or 
other approved performance standards). The potential risks found by the 
DRAS version 2.0 modeling were all from groundwater exposure pathways. 
As a result, current landfills with liner systems and leachate 
collection systems should dramatically lessen impacts on local 
groundwater conditions.
    DRAS does not have an option to model the impact of liners on 
landfill releases. Therefore, to examine the potential impact of 
liners, the Agency compared the levels calculated by the Industrial 
Waste Management Evaluation Model (IWEM), for single-lined and 
composite-lined landfills.\12\ IWEM is the ground-water modeling 
component of the Guide for Industrial Waste Management, used for 
recommending appropriate liner system designs for the management of 
RCRA Subtitle D industrial waste. The initial IWEM evaluation (Tier 1) 
provides a screening assessment with results that are protective over a 
range of conditions and situations. The results of the IWEM analysis 
indicate that the use of a composite-lined landfill would result in 
acceptable risk levels for the two key constituents of concern. The 
IWEM generally uses more protective assumptions than the DRAS model. 
For example, the IWEM model assumes that the drinking water well is at 
a fixed location along the center line of the potential plume of 
contamination at a distance of 150 meters from the unit; the DRAS model 
allows the well location to vary downgradient from the unit.
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    \12\ In IWEM, a single cay liner is a layer of compacted clay 
three feet thick (hydraulic conductivity of 1 x 10-7 cm/
sec), and a composite liner consists of a geomembrane liner (high 
density polyethylene) overlying the clay layer.
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    To further examine the effectiveness of composite liners, EPA also 
used the modeling performed for lined landfills in the recent listing 
rule for dye and pigment production wastes (February 24, 2005, 70 FR 
9138). In this rule, the Agency established a conditional exemption for 
wastes disposed in landfills meeting specified liner design 
requirements, similar to the proposal in today's notice. The results 
from that effort show that composite-lined landfills provided 
significant protection (about two orders of magnitude) compared to an 
unlined unit.\13\ Therefore, based on both the IWEM results and the 
modeling in the dye and pigment waste listing, EPA believes that 
disposal of F019 sludges from motor vehicle manufacturers in composite-
lined landfills (or other approved performance standards) is protective 
of human health and the environment.
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    \13\ The results for zinc and several other metals (lead, 
copper, and barium) demonstrated that composite lined landfills 
reduced risks from landfill releases factors of 133 to 269 compared 
to unlined units. See ``Risk Assessment Technical Background 
Document for the Dye and Pigment Industry Hazardous Waste Listing 
Determination,'' November 10, 2003, Table 2-1b, page 2-4.
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    The Agency also considered whether the presence of just a single 
clay liner would be sufficient to reduce the risks below levels of 
concern. In addition to the IWEM results that showed disposal in a 
composite-lined landfill was protective, this analysis also yielded 
levels that would be allowed for a landfill with a single clay liner 
and for an unlined landfill. For nickel, the levels that would be 
allowed for a single clay liner were approximately 3-fold higher than 
the allowable levels for an unlined unit. For arsenic, the allowable 
level for a single clay liner was approximately 7-fold higher than the 
allowable level for an unlined unit. Thus, a single clay liner (as 
defined in the IWEM model assumptions) may be sufficiently protective 
to allow disposal in a unit with such a single liner, because a single 
clay liner may reduce the risks from these constituents to levels below 
the DRAS levels of concern. (EPA is somewhat uncertain about the 
appropriateness of extending the apparent margin of safety afforded by 
a single clay liner from one model (IWEM) to another model's results 
(DRAS), and we are seeking comment on this approach.) Therefore, EPA is 
requesting comment on a second regulatory option that would allow 
disposal of this waste in all state-permitted municipal solid waste 
landfills (regulated under 40 CFR Part 258) and state-permitted 
industrial solid waste landfills (regulated under 40 CFR Part 257), 
even those that do not meet the liner design requirements in Sec.  
258.40, provided the landfills are equipped with at least a single clay 
liner.\14\ The second option, for example, would allow disposal in a 
state-permitted municipal landfill that was constructed prior to the 
effective date for the Sec.  258.40 regulations (an ``existing'' unit), 
provided the unit had at least a single clay liner. EPA expects that 
this would provide additional regulatory flexibility for generators, 
and would not be likely to result in adverse health effects.
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    \14\ This second proposed option would also allow disposal in a 
hazardous waste landfill regulated under Sec.  264.301 or Sec.  
265.3