# Hazardous Waste Identification Rule (HWIR): Identification and Listing of Hazardous Wastes

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URL: https://www.frixlaw.com/law-library/documents/fr%3A99-29067

## Record

- **Collection:** Federal Register
- **Document type:** Proposed Rule
- **Published:** November 19, 1999
- **Citation:** 64 FR 63382

## Text

SUMMARY: Today's action proposes to retain and amend the mixture rule
and the derived-from rule in the Resource Conservation and Recovery Act
(RCRA). The mixture and derived-from rules ensure that hazardous wastes
that are mixed with other wastes or that result from the treatment,
storage or disposal of hazardous wastes do not escape regulation and
thereby cause harm to human health and the environment.
EPA is proposing two revisions to the mixture and derived-from
rules. These revisions would narrow the scope of the mixture and
derived-from rules, tailoring the rules to more specifically match the
risks posed by particular wastes. The first is an exemption for
mixtures and/or derivatives of wastes listed solely for the
ignitability, corrosivity, and/or reactivity characteristics. The
second is a conditional exemption from the mixture and derived-from
rules for ``mixed wastes'' (that is, wastes that are both hazardous and
radioactive).
Today's document also discusses an implementation framework for an
exemption from hazardous waste management for wastes that meet
chemical-specific exemption levels, also known as the Hazardous Waste
Identification Rule (HWIR) exemption. The HWIR exemption would identify
a broad set of listed hazardous waste that could be safely managed in
nonhazardous waste management units. The current version of the model
that could be used to derive the exemption levels is designed to
evaluate simultaneous exposures across multiple media and pathways in
order to estimate the resulting health and environmental effects.
Before using a revised risk assessment to support a final regulatory
action, we would propose the HWIR exemption, providing public notice
and the opportunity to comment on the revised risk assessment and
resulting exemption levels.
In addition, today's document discusses the possibility of revising
the Land Disposal Restrictions (LDRs) by replacing technology-based
treatment standards in the RCRA regulations with risk-based treatment
standards.

DATES: To make sure we consider your comments on revisions to the
mixture and derived-from rules (Sections I-IV, Sections XXI-XXVI (as
applicable) of the preamble and proposed regulatory language amending
40 CFR part 261), they must be postmarked on or before February 17,
2000.
To make sure we consider your comments on the discussed
concentration-based HWIR exemption and the possible revisions to the
LDR Treatment Standards (Sections V-XX and Sections XXI-XXVI (as
applicable) of the preamble), they must be postmarked on or before May
17, 2000.

ADDRESSES: Please send an original and two copies of your comments
referencing Docket number F-99-WH2P-FFFFF to (1) if using regular U.S.
Postal Service mail: RCRA Docket Information Center, Office of Solid
Waste (5305W), U.S. Environmental Protection Agency Headquarters (EPA,
HQ), 401 M Street, S.W., Washington, D.C.. 20460, or (2) if using
special delivery, such as overnight express service: RCRA Docket
Information Center (RIC), Crystal Gateway One, 1235 Jefferson Davis
Highway, First Floor, Arlington, Virginia 22202. It would also be
helpful, although not mandatory, to include an electronic copy by
diskette or Internet email. In this case, send your comments to the
RCRA Information Center on labeled personal computer diskettes in ASCII
(TEXT) format or a word processing format we can convert to ASCII
(TEXT). Please include on the disk label the name, version, and edition
of your word processing software as well as your name and docket number
F-99-WH2P-FFFF. Protect your diskette by putting it in a protective
mailing envelope. To send a copy by Internet email, address it to:
[email protected]. Make sure this electronic copy is in an
ASCII format that doesn't use special characters or encryption. Cite
the docket Number F-99-WH2P-FFFFF in your electronic file.
The RCRA Information Center is located at Crystal Gateway One, 1235
Jefferson Davis Highway, First Floor, Arlington Virginia. If you would
like to look at and copy supporting information for RCRA rules, please
make an appointment with the RCRA Information Center by calling (703)
603-9230. Docket hours are from 9 A.M. to 4 P.M. Monday through Friday,
except for Federal holidays. You may copy up to 100 pages from any
regulatory document at no cost. Additional copies cost $0.15 per page.

FOR FURTHER INFORMATION CONTACT: For general information about this
proposed rule, contact the RCRA Hotline, Office of Solid Waste, U.S.
Environmental Protection Agency, Washington, DC 20460, (800) 424-9346
(toll free); TDD (800) 553-7672 (hearing impaired); in the Washington,
D.C. metropolitan area the number is (703) 412-9810; TDD (703) 486-3323
(hearing impaired). For technical information on this proposed rule,
contact Adam Klinger at (703) 308-3267 or Tracy Atagi at (703) 308-
8672; for specific information on the risk modeling system, contact
David Cozzie at (703) 308-0479. To get copies of the reports or other
materials referred to in this proposal, contact the RCRA Docket at the
phone number or address listed above.

SUPPLEMENTARY INFORMATION: The proposal and other material associated
with this action can be electronically accessed on the Internet at
http://www.epa.gov/epaoswer/hazwaste/id
The official record for this rulemaking will be kept in paper form.
Accordingly, EPA 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 record maintained at the address in ADDRESSES at the beginning
of this document.
We will respond to submitted comments, whether written or
electronic, 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 electronically submitted comments other
than to seek clarification of comments that may be garbled in
transmission or during conversion to paper form, as discussed above.

Affected Entities

Entities potentially affected by this proposed action are
generators of industrial hazardous waste, and entities that treat,
store, transport and/or dispose of these wastes. Different sets of
entities (i.e., industrial and service sectors) are affected by
different provisions of this regulatory proposal, as displayed below:
This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be affected by this
action.

[[Page 63383]]

------------------------------------------------------------------------
List of potentially
SIC code NAICS code affected U.S.
industrial entities
------------------------------------------------------------------------
A. Proposed Revision to 40 CFR
261.3 RCRA Mixture-and-
Derived-from Rules:
2800...................... 32xxxx........... Chemicals & allied
products
manufacturing.
2819...................... Five possible Industrial inorganic
codes. chemicals
manufacturing.
2821...................... 325211........... Plastics materials &
resins
manufacturing.
2833...................... 325411........... Medicinal chemicals &
botanicals
manufacturing.
2834...................... 325412........... Pharmaceutical
preparations
manufacturing.
2851...................... 32551............ Paints & allied
products
manufacturing.
2869...................... Five possible Industrial organic
codes. chemicals
manufacturing.
2879...................... 32532............ Pesticides &
agricultural
chemicals
manufacturing.
3089...................... Four possible Plastics products
codes. manufacturing.
3241...................... 32731............ Hydraulic cement
products
manufacturing.
3479...................... Four possible Fabricated metal
codes. coating & allied
services.
3711...................... Five possible Motor vehicle &
codes. passenger car bodies
manufacturing.
4212...................... 562111 & 562112.. Local trucking
services (industrial
waste shipment).
4953...................... Five possible Refuse (industrial
codes. waste) treatment/
disposal services.
7389...................... 36 possible codes Business services.
7532...................... 811121........... Auto repair & auto
paint shops.
9511...................... 92411............ Waste management.
9711...................... 811121........... National security
(military bases).
------------------------------------------------------------------------
Explanatory Notes:
(1) SIC = 1987 Standard Industrial Classification system (U.S.
Department of Commerce's traditional code system last updated in
1987).
(2) NAICS = 1997 North American Industrial Classification System (U.S.
Department of Commerce's new code system as of 1997).
(3) Refer to the Internet website http://www.census.gov/epcd/www/
naicsdev.htm for additional information and a cross-walk table for the
SIC and NAICS codes systems.

This table lists those entities that EPA believes could be affected
by this proposed action, based on industrial sectors identified in the
economic analysis in support of this proposal. A total of about 120
entities are expected to benefit from the proposed revisions to 40 CFR
261.3 in the 17 industrial sectors listed above, but primarily in the
chemicals and allied products sector (i.e., SIC code 28, or NAICS code
325). Other entities not listed in the table also could be affected. To
determine whether your facility is regulated by this action, you should
examine 40 CFR parts 260, 261 and 268 carefully in concert with the
amended rules found at the end of this Federal Register document. If
you have questions regarding the applicability of this action to a
particular entity, consult the persons listed in the preceding FOR
FURTHER INFORMATION CONTACT section.

Acronyms
------------------------------------------------------------------------
Acronym Definition
------------------------------------------------------------------------
3MRA......................... Multimedia, Multipathway and
Multireceptor Risk Assessment.
AOI.......................... Area of Interest.
APA.......................... Administrative Procedures Act.
AT........................... Aerated Tank.
BDAT......................... Best Demonstrated Available Technology.
CERCLA....................... Comprehensive Environmental Response,
Compensation and Liability Act.
CFR.......................... Code of Federal Regulations.
CMA.......................... Chemical Manufacturers Association.
CWA.......................... Clean Water Act.
DOT.......................... Department of Transportation.
EPA.......................... Environmental Protection Agency.
EPACMTP...................... EPA's Composite Model for Leachate
Migration with Transformation Products.
EXAMS........................ Exposure Analysis Modeling System.
EXAMSIO...................... Exposure Analysis Modeling System--Input
Output Interface.
FRAMES....................... Framework for Risk Analysis in Multimedia
Environmental Systems.
GIRAS........................ Geographic Information Retrieval and
Analysis System.
HEAST........................ Health Effects Assessment Summary Table.
HQ........................... Hazard Quotient.
HSWA......................... Hazardous and Solid Waste Amendments of
1984.
HWIR......................... Hazardous Waste Identification Rule.
HWIR99....................... Hazardous Waste Identification Rule--1999
Framework.
ICR.......................... Information Collection Request.
IEUBK........................ Integrated, Exposure, Uptake and
BioKinetic Model.
IRIS......................... Integrated Risk Information System.
ISCST3....................... Industrial Source Complex Short Term
model.
LAU.......................... Land Application Unit.
LCR.......................... Lead and Copper Rule.
LDR.......................... Land Disposal Restriction.
LF........................... Landfill.
LLMW......................... Low Level Mixed Wastes.
LLRWDF....................... FLow Level Radioactive Waste Disposal
Facility.
LOEL......................... Lowest Observed Effects Level.

[[Page 63384]]

MACT......................... Maximum Achievable Control Technology.
MCL.......................... Maximum Containment Level.
MINTEQA2..................... Geochemical speciation model; originally
a combination of Mineral Equilibrium
Model (MINEQL) and the thermodynamic
database WATEQ3.
NAPL......................... Non-Aqueous Phase Liquid.
NOEL......................... No Observed Effects Level.
NRC.......................... Nuclear Regulatory Commission (NRC).
NTTAA........................ National Technology Transfer and
Advancement Act.
OMB.......................... Office of Management and Budget.
ORD.......................... Office of Research and Development.
OIRM......................... Office of Information and Resources
Management.
OSW.......................... Office of Solid Waste.
OSWER........................ Office of Solid Waste and Emergency
Response.
PBMS......................... Performance Based Measurement System.
QA/QCl....................... Quality Assurance/Quality Control.
RCRA......................... Resource Conservation Recovery Act.
RfD.......................... Reference Dose.
RfC.......................... Reference Concentration.
RIC.......................... RCRA Docket Information Center.
RMS.......................... Root Mean Square.
SAB.......................... Science Advisory Board.
SAMSON....................... Solar and Meteorological Surface
Observation Network.
SBREFA....................... Small Business Regulatory Enforcement
Fairness Act.
SCIM......................... Sampled Chronological Input Model.
SI........................... Surface Impoundment.
SPARC........................ System Performs Automated Reasoning in
Chemistry.
SSLs......................... Soil Screening Levels.
SVOC......................... Semi-Volatile Organic Compound.
SZM.......................... Saturated Zone Module.
TC........................... Toxicity Characteristic.
TCLP......................... Toxicity Characteristic Leaching
Procedure.
TDD.......................... Telecommunications Device for the Deaf.
TOC.......................... Total Organic Carbon.
TRI.......................... Toxic Release Inventory.
TSCA......................... Toxic Substance Control Act.
TSDF......................... Treatment, Storage, and Disposal
Facility.
TSS.......................... Total Suspended Solid.
UMRA......................... Unfunded Mandates Reform Act.
USLE......................... Universal Soil Loss Equation.
UTS.......................... Universal Treatment Standards.
VO........................... Volatile Organics.
VOC.......................... Volatile Organic Compounds.
VZM.......................... Vadose Zone Module.
WMU.......................... Waste Management Unit.
WP........................... Waste Pile
------------------------------------------------------------------------

Outline

Background

I. Under what legal authority is EPA proposing these regulatory
changes?
II. What is EPA proposing today and on what other actions is EPA
seeking comment?

Retaining the Mixture and Derived-From Rules

III. Why is EPA proposing to retain the mixture and derived-from
rules?

Proposed Revisions to 40 CFR 261.3

IV. How and why is EPA proposing to revise the hazardous waste
identification regulations for mixtures and derived-from wastes?

HWIR Exemption Options

V. Why is EPA developing a chemical-based HWIR exemption for listed
hazardous waste (including both mixtures and derived-from waste)?
VI. What options is EPA developing for the HWIR exemption?
VII. What wastes would be eligible for an HWIR exemption?
VIII. What level of governmental review would be needed for an HWIR
exemption claim?
IX. For the generic HWIR exemption, what steps would I follow before
my waste could be exempted?
X. Once the waste becomes exempt, what RCRA requirements might still
apply?
XI. For the generic HWIR exemption, what conditions and requirements
would I be required to fulfill to maintain the exemption?
XII. What would be the conditions and requirements for the landfill-
only HWIR exemption?
XIII. What would happen if I do not comply with the conditions and
the requirements of the HWIR exemption?
XIV. What might the regulatory language for the HWIR exemption look
like?

HWIR Risk Assessment

XV. What is the goal of the HWIR risk assessment?
XVI. How did EPA develop the current version of the HWIR risk
assessment?
XVII. What are the results of the current version of the risk
assessment?
XVIII. How was the HWIR exemption list of chemicals developed?
XIX. How would EPA use the results of the risk assessment to set
HWIR exemption levels?

Possible Revision to LDR Treatment Standards

XX. How might EPA use the results of the HWIR model to revise the
hazardous waste LDR treatment standards?

Economic Impacts

XXI. What are the economic impacts of today's proposed regulatory
changes?

[[Page 63385]]

Relationship to Other Programs

XXII. How would the HWIR exemption relate to other programs?
A. Would HWIR change how you determine if a waste is hazardous?
B. Could a characteristic hazardous waste be exempt under HWIR?
C. How would the HWIR exemption differ from the delisting
process per 40 CFR 260.22?
D. How would HWIR affect TSDF closure requirements for my
facility?
E. How would HWIR affect the Land Disposal Restriction (LDR)
Program?
F. How would HWIR relate to the RCRA air emission standards?
G. Would HWIR affect ``Use Constituting Disposal'' regulations?
H. Could hazardous waste debris become under HWIR?
I. Would contaminated media be eligible for an HWIR exemption?
J. Does the final HWIR-Media Rule impact HWIR?
K. How would HWIR impact actions under the Superfund program
(CERCLA)?
L. How does HWIR relate to the draft Industrial D Voluntary
Guidance?
M. How does HWIR relate to the Comparable Fuels Exemption?
N. How would HWIR affect mixed waste?
O. How does HWIR relate to the Sewage Sludge Regulatory Program?

State Authorization

XXIII. How would today's proposed regulatory changes be administered
and enforced in the States?

Administrative Requirements

XXIV. How has EPA fulfilled the administrative requirements for this
proposed rulemaking?
A. Executive Order 12866: Determination of Significance
B. Regulatory Flexibility Act
C. Paperwork Reduction Act (Information Collection Request)
D. Unfunded Mandates Reform Act
E. Executive Orders on Federalism
F. Executive Order 13084: Consultation and Coordination with
Indian Tribal Governments
G. Executive Order 13045: Protection of Children from
Environmental Health Risks and Safety Risks
H. National Technology Transfer and Advancement Act of 1995

References

XXV. What are some key documents containing information supporting
this notice?

Request for Comment

XXVI. On what issues is EPA specifically seeking public comment?

Background

I. Under What Legal Authority Is EPA Proposing These Regulatory
Changes?

These regulations are proposed under the authority of Sections
2002(a), 3001, 3002, 3004, and 3006 of the Solid Waste Disposal Act of
1970, as amended by the Resource Conservation and Recovery Act of 1976
(RCRA), as amended by the Hazardous and Solid Waste Amendments of 1984
(HSWA), 42 U.S.C. Sec. 6912(a), 6921, 6922, 6924, 6926.

II. What Is EPA Proposing Today and on What Other Actions Is EPA
Seeking Comment?

A. What Is Included In Today's Notice?
Today EPA:
1. Proposes to retain the mixture and derived-from rules, currently
set forth in 40 CFR 261.3(a)(2)(iii), 261.3(a)(2)(iv) and
261.3(c)(2)(i). As explained in Section III, these rules, which are
currently in effect on an emergency basis, regulate wastes that are
mixed with, or are derived from the treatment, storage, or disposal of,
listed hazardous wastes.
2. Proposes to narrow the scope of the mixture and derived-from
rules by exempting mixtures and derivatives of wastes listed solely for
the ignitability, corrosivity, and/or reactivity characteristics which
no longer exhibit any characteristic of hazardous waste and comply with
land disposal restrictions applicable to characteristic wastes.
3. Discusses an implementation framework for two exemptions from
Subtitle C management requirements for wastes meeting a set of
conditions and procedures. The two options are:
(a) A ``generic'' exemption that has no specific requirements as to
how the waste is managed once conditions of the exemption are met; and
(b) a ``landfill-only'' exemption that limits the subsequent
management of the exempted waste to disposal in a landfill and
prohibits placement on the land before disposal;
4. Discusses the current version of the risk assessment that EPA
intends to use to create exemption levels to be used in the
implementation framework; and
5. Discusses whether to revise the Land Disposal Restrictions by
replacing the technology-based treatment standards in 40 CFR 268.40 and
268.48 with risk-based treatment standards.
B. What Related Regulatory Action Is EPA Also Proposing Elsewhere in
Today's Federal Register?
In a separate proposal published elsewhere in the Federal Register
today, we are also proposing to conditionally exempt hazardous waste
mixed with low-level radioactive wastes (low-level mixed wastes, or
LLMW) or mixed with Naturally Occurring and/or Accelerator-produced
Radioactive Material (NARM mixed waste) from the storage,
transportation, and disposal requirements of RCRA. Treated LLMW and
NARM mixed waste would be exempt from RCRA hazardous waste
transportation and disposal facility requirements if it is disposed at
a low level radioactive waste disposal facility (LLRWDF) regulated by
the Nuclear Regulatory Commission (NRC). In addition, we are also
proposing that untreated LLMW and NARM mixed waste generated by the NRC
licensees may be stored according to NRC regulations instead of RCRA
hazardous waste storage regulations.
C. What Is EPA's Legal Obligation With Respect to This Proposal?
Our legal obligation for this proposal stems from EPA's fiscal year
1993 appropriation act, which required EPA to revise the mixture and
derived-from rules, 40 CFR 261.3(a)(2)(iv) and 40 CFR 261.3(c)(2)(i),
by October 1, 1994. (Pub. L. No. 102-389, 106 Stat. 1571). Congress
made the deadline enforceable under RCRA's citizen suit provision,
section 7002, 42 U.S.C. Sec. 6972. We did not meet this deadline for
revisions, and in early October 1994 several groups of waste generating
and waste managing industries filed suits to enforce the deadline.
Two of the cases were consolidated and a third was dismissed with
the plaintiffs being added as intervenors to the consolidated cases.
Environmental Technology Council v. Browner, C.A. No. 94-2346
(TFH)(D.D.C.). The U.S. District Court for the District of Columbia
entered a consent decree resolving the consolidated cases on May 3,
1993. The consent decree, as subsequently amended, required the
Administrator to sign a proposal to revise the mixture and derived-from
rules by November 13, 1995 and a notice of final action on the proposal
by February 13, 1997. The decree reflects the parties' understanding
that EPA's leading option was developing a multipathway risk assessment
to establish constituent-specific, risk-based ``exit levels'' for
listed hazardous wastes. It does not, however, specify what types of
revisions EPA needs to propose or promulgate. On November 13, 1995, the
Administrator signed the proposed Hazardous Waste Identification Rule
(HWIR) to revise the mixture and derived-from rules. This proposal was
published in the Federal Register on December 21, 1995. (60 FR 66344).
It proposed a set of exemption levels for hundreds of hazardous
constituents. Many of these exemption levels were based on a complex
multipathway risk assessment. The notice also proposed to revise the
derived-from rule to provide relief for

[[Page 63386]]

hazardous wastes listed because they exhibited the characteristics of
ignitability, corrosivity and/or reactivity, and solicited comment on
the concept of providing a separate exemption for hazardous wastes
mixed with low level radioactive wastes.
We received extensive comments, many critical, on the 1995 HWIR
proposal, particularly with respect to the scientific risk assessment.
We continued to view risk-based exemption levels based on a
multipathway risk assessment as our preferred option. We concluded that
considerable work needed to be done to resolve the complex scientific
and technical issues raised in the comments. We negotiated with the
parties to extend the deadlines in the decree to allow us time to
address these issues. On April 11, 1997, the District Court entered an
order amending the consent decree in Environmental Technology Council
v. Browner.
The amended decree revised the deadlines for a revision to the
mixture and derived-from rules, with an October 31, 1999 deadline for
the Administrator to sign a proposal, and an April 30, 2001 deadline to
sign a notice taking final action. The amended decree also included 11
different provisos that we are obligated to make our best efforts to
address. They require EPA to solicit comment on a number of issues
related to risk assessment and to the implementation scheme we were
developing for the exemption levels that the risk assessment would
support. Today's rulemaking, in conjunction with the mixed waste
proposal, also to be published today, fulfills our obligations under
the consent decree.
Specifically, the amended consent decree required EPA to sign a
notice proposing revisions to the mixture and derived-from rules in 40
CFR 261.3(a)(2(iv) and (c)(2)(i), and request comment on the 11
provisos listed in the decree. The consent decree reflected EPA's
intent to further study three broad areas regarding hazardous
constituents in hazardous waste and to establish a constituent-based
exemption from hazardous waste regulation for low-risk wastes currently
subject to RCRA subtitle C regulation. It also reflected EPA's intent
to ``make best efforts'' to describe and discuss the items in the 11
provisos.
The three areas of study were: (a) Modeling of anaerobic
biodegradation of hazardous constituents in the saturated zone, (b) the
physical relationship between waste concentrations and leachate
concentrations, and of mass limitations in leachate, and (c) the use of
additional toxicity data from sources outside EPA. Seven of the 11
provisos concerned particular issues for EPA to study with respect to
these three areas of study. Three provisos concerned options for
implementing the exemption levels EPA expected to derive from the
modeling. Finally, one proviso concerned an exemption from hazardous
waste regulation for certain radioactive hazardous mixed wastes
generated by nuclear power plants that are subject to regulation by the
Nuclear Regulatory Commission (or states authorized to implement those
regulations).
As contemplated in the consent decree, we developed a new model to
analyze hazardous constituents in hazardous waste. We addressed the
seven modeling-related issues listed in the provisos, either by
incorporating steps in the model to produce data with respect to those
issues, or by studying the issues and concluding that it was not
possible to include them in a model at this time (see Sections XV to
XIX). We addressed the three implementation-related provisos by
developing a plan to implement a program to exempt certain waste
currently regulated as hazardous waste under RCRA subtitle C from full
hazardous waste regulation, based on meeting risk-based exemption
levels for hazardous constituents (see Sections V to XIV). Finally, as
stated above, the mixed waste provision is addressed in a separate
notice of proposed rulemaking.
Despite a concerted, sustained effort, we did not succeed in
developing within the consent decree time frame a risk assessment
capable of generating reliable exemption levels. We concluded that we
could not implement our preferred option by the October 31 deadline for
proposed revisions. Moreover, we were not sure how much additional time
we would need to address the remaining modeling issues. We concluded
that we would better serve the public interest and better utilize our
rulemaking resources by proceeding with the options that were ready for
proposal rather than seeking another deadline extension for the
purposes of resolving the complex technical issues presented by the
risk assessment. Therefore, we decided to propose (1) Revisions to the
mixture rule for wastes listed because they exhibit the characteristics
of ignitability, corrosivity, and/or reactivity described in Section IV
below, and (2) a set of conditional exemptions from various Subtitle C
regulations (including the mixture and derived-from rules) for certain
low-level radioactive wastes as described in the separate proposal
published elsewhere today, including the conditional exemptions from
the mixture and derived-from rules proposed here today.
D. How Does Today's Notice Relate to the 1995 HWIR Proposal?
In 1995, we published an HWIR proposal that included revisions to
the mixture and derived-from rules and a discussion of exemptions
similar to the HWIR exemption scenarios discussed in today's notice (60
FR 66344 (December 21, 1995)). Comments we received on the HWIR95
proposal have been invaluable in crafting today's notice, particularly
in revising the risk assessment, and we will formally respond to those
comments, as well as to comments on today's notice, when we promulgate
a final rule. Today's notice is technically a supplement to HWIR95.
However, because it has been four years since the 1995 HWIR proposal,
we have written today's notice as a stand alone proposal. You do not
have to read the 1995 proposal to understand today's notice.
E. What Other Regulatory Options Have Been Received From EPA
Stakeholders?
In August 1999, we received a paper from the Chemical Manufacturers
Association (CMA) describing five additional regulatory options,
including suggested regulatory language, for revising the mixture and
derived-from rules (see Memorandum from Dorothy Kellogg, CMA to
Elizabeth Cotsworth, Acting Director, Office of Solid Waste, August
1999). CMA forwarded these options seeking regulatory relief for some
specific high-volume wastes that they believe are low-risk and feel
that EPA could propose to exempt with very little delay. Although we
have not had time to analyze these options, we would like to present
them here for others to provide their views.
Three of these options involve exempting from the hazardous waste
derived-from rule: (1) Residues from the combustion of listed hazardous
waste, (2) leachate from the land disposal of listed hazardous waste
(that is subsequently managed in a system regulated under the Clean
Water Act), and (3) sludges from the biological treatment of listed
hazardous wastewaters. In each of these cases, CMA argues that the
wastes are both physically and chemically dissimilar from the wastes
that were originally listed. In addition, CMA notes that combustion and
biological treatment can greatly reduce or eliminate organic chemicals.
Under the options presented in CMA's discussion papers, each of these
wastes would not be hazardous, even though they are generated from the

[[Page 63387]]

treatment, storage or disposal of hazardous waste, unless they exhibit
one or more of the hazardous waste characteristics of 40 CFR Part
261.3.
CMA's paper does not, however, explicitly address how LDR treatment
standards would apply to these residues. Especially in the case of the
ash and wastewater treatment sludge, which would often result from LDR
treatment, if the wastes do not meet the LDR standards, then there
would be a question of whether further treatment to meet LDRs would be
required.
EPA has already been considering another possible approach for
addressing combustion residues, which would list these derived-from
wastes under their own multi-source listing code, similar to multi-
source leachate (F039). This listing would continue to regulate these
wastes as hazardous, but application of other requirements could be
tailored to fit the physical and chemical properties of these wastes.
EPA is developing an Advance Notice of Proposed Rule Making (ANPRM)
that would discuss the idea of a new listing for combustion residues.
More information on this ANPRM (SAN No. 4093) can be found in the most
recent agenda of regulatory and deregulatory actions (64 FR 21987
(April 26, 1999)).
In their materials, CMA has forwarded specific changes to
regulatory language currently in effect and found in the Code of
Federal Regulations (CFR). EPA has not evaluated this language and
presents it here to enhance public dialogue on these ideas. CMA
suggests that we modify 40 CFR 261.3(c)(2)(ii) and add the following
language:
``[1] Wastes derived from burning any listed hazardous waste in a
permitted or interim status hazardous waste combustion device; [2]
Leachate derived from landfills or land treatment units containing
listed hazardous waste, which is managed in a wastewater treatment
system the discharge of which is subject to regulation under either
section 402 or section 307(b) of the Clean Water Act (including
wastewater at facilities which have eliminated the discharge of
wastewater); [3] Wastes derived from the aggressive biological
treatment of listed hazardous wastewaters in a wastewater treatment
systems the discharge of which is subject to regulation under either
section 402 or section 307(b) of the Clean Water Act (including
wastewater at facilities which have eliminated the discharge of
wastewater).''
The other two options presented in the paper involve specific
wastes that result from the mixture of hazardous wastes with solid
wastes. One option involves an expansion of the current ``headworks''
exemption in 40 CFR 261.3(a)(2)(iv)(A) and (B). The headworks exemption
exempts from the mixture rule wastewaters containing small quantities
of particular F-listed solvents, based on the mass-balance flow of
these solvents through the headworks of industrial wastewater treatment
systems. CMA's options paper requests that this exemption be amended in
three ways.
First, CMA's suggested revision would allow direct monitoring of
the actual concentration of spent solvents in untreated wastewater to
demonstrate compliance. The current requirement is to perform a weekly
mass balance of the solvents entering the system. Losses due to
volatilization must be counted in the mass balance determination under
the current system. We note that CMA's suggested wastewater monitoring
would provide accurate data at the point the wastewater enters the
treatment system, but the losses due to volatilization would not be
counted in this approach.
Second, under the revised headworks exemption, benzene, 2-
ethoxyethanol, 2-nitropropane, and 1,1,2-trichloroethane would be
incorporated into the list of chemicals. These four chemicals were
added to the 261.31 list of spent solvents in 1986 but the exemption
does not currently include these chemicals.
Third, under the revised headworks exemption, multi-source leachate
(F039) derived solely from the disposal of the spent solvents listed in
40 CFR 261.31 would be eligible for the exemption.
Again, CMA has forwarded specific changes to regulatory language
currently in effect and found in the Code of Federal Regulations (CFR).
EPA has not evaluated this language and presents it here to enhance
public dialogue on these ideas. CMA suggests that we modify 40 CFR
261.3(a)(2)(iv)(A) and (B) to read as follows:
``40 CFR 261.3(a)(2)(iv)(A). One or more of the following
solvents listed in Sec. 261.31--carbon tetrachloride,
tetrachloroethylene, trichloroethylene [add solvents that meet the
standards to be included in this paragraph], including multi-source
leachate derived from the disposal of these solvents and no other
listed hazardous wastes--Provided, That either the actual
concentration of these solvents or the maximum total weekly usage of
these solvents (other than the amounts that can be demonstrated not
to be discharged to wastewater) divided by the average weekly flow
of wastewater into the headworks of the facility's wastewater
treatment or pretreatment system does not exceed 1 part per million;
or * * *
40 CFR 261.3(a)(2)(iv)(B). One or more of the following solvents
listed in Sec. 261.31--methylene chloride, 1,1,1-trichloroethane,
chlorobenzene, o-dichlorobenzene, cresols, cresylic acid, nitrobenzene,
toluene, methyl ethyl ketone, carbon disulfide, isobutanol, pyridine,
spent chlorofluorocarbon solvents [add solvents that meet the standards
to be included in this paragraph], including multi-source leachate
derived from the disposal of these solvents and no other listed
hazardous wastes--Provided, That either the actual concentration of
these solvents or the maximum total weekly usage of these solvents
(other than the amounts that can be demonstrated not to be discharged
to wastewater) divided by the average weekly flow of wastewater into
the headworks of the facility's wastewater treatment or pretreatment
system does not exceed [25] part per million; or * * *''
These modifications add 4 chemicals to either paragraph (A) or (B),
include leachate derived from the disposal of these solvents and no
other listed hazardous waste and allow for the demonstration by direct
measurement that concentrations do not exceed the specified levels.
Note the 25 ppm threshold specified in 40 CFR 261.3(a)(2)(iv)(B) is the
threshold within current regulations, and we do not believe it was
CMA's intention to alter this level to 1 ppm, the level stated in their
materials.
The other regulatory option involving hazardous waste mixtures
would be an expansion of a current exemption for ``de minimis'' losses
that result from the manufacture of commercial chemical product. The
current exemption, found in 40 CFR 261.3(a)(2)(iv)(D), exempts from the
mixture rule small losses of a commercial chemical product that can
result from normal handling of the chemicals during the manufacturing
process. The existing exemption applies to some but not all hazardous
wastes listed in 40 CFR 261.33 (see 46 FR 56586). CMA's suggested
expansion of this option would also exempt small losses from the normal
handling of all listed hazardous wastes (instead of just the handling
of commercial chemical products). One rationale for the current ``de
minimis'' exemption is that a facility has little economic incentive to
allow spills, leaks or other losses of commercial products. With
respect to wastes, CMA believes that tank and container and air
emission management standards of 40 CFR Parts 264 and 265, Subparts I,
J, BB, and CC serve to encourage safe management of these wastes.

[[Page 63388]]

Specific changes forwarded by CMA would modify 40 CFR
261.3(a)(2)(iv)(D). EPA has not evaluated this language and presents it
here to enhance public dialogue on these suggestions. Their language
reads as follows:
``40 CFR 261.3(a)(2)(iv)(D). One or more hazardous wastes listed
in Subpart D, arising from de minimis losses of these materials from
manufacturing and related operations in which these materials are
generated. For purposes of paragraph (a)(2)(iv)(D), ``de minimis''
losses include those from normal material handling operations (e.g.,
spills from the unloading or transfer of materials from bins or
other containers, leaks from pipes, valves or other devices used to
transfer materials); minor leaks of process equipment, storage tanks
or containers; leaks from well maintained pump packings and seals;
sample purging; relief device discharges; discharges from safety
showers and rinsing and cleaning of personal safety equipment; and
rinsate from empty containers or from containers that are rendered
empty by that rinsing; or''
Note that the phrase ``One or more hazardous wastes listed in
Subpart D'' replaces the more narrow eligibility contained in the
current regulation as ``a discarded commercial chemical product, or
chemical intermediate listed in 261.33.'' Also note the origin of these
wastes has been made broader by the inclusion of the term ``generated''
replacing the phrase ``used as raw materials or are produced in the
manufacturing process.''
We request comment on the merits and drawbacks of all these
possible revisions to the mixture and derived-from rules and on how LDR
standards should apply. We also request any data that may help us to
further evaluate (a) the potential risks to human health and the
environment, (b) any special or unique technical considerations, and
(c) the economic effects of each of the possible revisions.

Retaining the Mixture and Derived-From Rules

III. Why Is EPA Proposing To Retain the Mixture and Derived-From Rules?

A. What Are the Mixture and Derived-From Rules?
The mixture and derived-from rules are a part of the RCRA
regulations that define which wastes are considered to be hazardous and
therefore subject to RCRA Subtitle C regulations. The mixture rule
discussed in today's notice refer specifically to 40 CFR
261.3(a)(2)(iii) and (iv). Under the mixture rule, a solid waste
becomes regulated as a hazardous waste if it is mixed with one or more
listed hazardous wastes The derived-from rule discussed in today's
notice refers specifically to 40 CFR 261.3(c)(2)(i). Under the derived-
from rule, any solid waste generated from the treatment, storage, or
disposal of a hazardous waste remains regulated as a hazardous waste.
These derived-from wastes include wastes such as sludges, spill
residues, ash, emission control dust, and leachate.
B. What Is the Legal History of the Mixture and Derived-From Rules?
EPA promulgated the mixture and derived-from rules in 1980 as part
of the comprehensive ``cradle to grave'' requirements for managing
hazardous waste. 45 FR 33066 (May 19, 1980). Numerous industries that
generate hazardous wastes challenged the 1980 mixture and derived-from
rules in Shell Oil Co. v. EPA, 950 F. 2d 741 (D.C. Cir. 1991). In
December 1991 the D.C. Circuit Court of Appeals vacated the rules
because they had been promulgated without adequate notice and
opportunity to comment. The court, however, suggested that EPA might
want to consider reinstating the rules pending full notice and comment
in order to ensure continued protection of human health and the
environment.
In response to this decision, we promulgated an emergency rule
reinstating the mixture and derived-from rules as interim final rules
without providing notice and opportunity to comment. 57 FR 7628 (March
3, 1992). We also promulgated a ``sunset provision'' which provided
that the mixture and derived-from rules would remain in effect only
until April 28, 1993. Shortly after, we published a proposal containing
several options for revising the mixture and derived-from rules. See 57
FR 21450 (May 20, 1992). The May 1992 proposal and the time pressure
created by the ``sunset provision'' generated significant controversy.
In response, Congress included in EPA's FY1993 appropriation several
provisions addressing the mixture and derived-from rules. Pub. L. No.
102-389, 106 Stat. 1571. First, Congress nullified the sunset provision
by providing that EPA could not promulgate any revisions to the rules
before October 1, 1993, and by providing that the reinstated
regulations could not be ``terminated or withdrawn'' until revisions
took effect. However, to ensure that we could not postpone the issue of
revisions indefinitely, Congress also established a deadline of October
1, 1994 for the promulgation of revisions to the mixture and derived-
from rules. Congress made this deadline enforceable under RCRA's
citizen suit provision, section 7002.
On October 30, 1992, we published two notices, one removing the
sunset provision, and the other withdrawing the May 1992 proposal. (See
57 FR 49278, 49280). We had received many comments criticizing the May
1992 proposal. The criticisms were due, in a large part, to the very
short schedule imposed on the regulation development process itself.
Commenters also feared that the proposal would result in a
``patchwork'' of differing State programs because some states might not
adopt the revisions. This fear was based on the belief that States
would react in a negative manner to the proposal and refuse to
incorporate it into their programs if finalized. Finally, many
commenters also argued that the risk assessment used to support the
proposed exemption levels failed to provide adequate protection of
human health and the environment because it evaluated only the risks of
human consumption of contaminated groundwater and ignored other
pathways that could pose greater risks. Based on these concerns, and
based on EPA's desire to work through the individual elements of the
proposal more carefully, we withdrew the proposal.
Subsequently, a group of waste generating industries challenged the
March 1992 action that reinstated the mixture and derived-from rules
without change. Mobil Oil Corp. v. EPA, 35 F.3d 579 (D.C. Cir. 1994).
The court rejected this challenge, adopting our argument that the
appropriations act made the challenge moot because it prevented both us
and the courts from terminating or withdrawing the interim rules before
we revised them, even if we failed to meet the statutory deadline for
the revisions.
We did not meet Congress' October 1, 1994 deadline for revising the
mixture and derived-from rules. In early October 1994 several groups of
waste generating and waste managing industries filed citizen suits to
enforce the October 1, 1994 deadline for revising the mixture and
derived-from rules. The U.S. District Court for the District of
Columbia entered a consent decree resolving the consolidated cases on
May 3, 1993. Environmental Technology Council v. Browner, C.A. No. 94-
2119 (TFH) (D.D.C. 1994). The consent decree originally required the
Administrator to sign a proposal to amend the mixture and derived-from
rules by November 13, 1995 and a notice of final rulemaking by December
15, 1996, and specified that the deadlines in the appropriations act do
not apply to any rule revising the

[[Page 63389]]

separate regulations that establish jurisdiction over media
contaminated with hazardous wastes. On November 13, 1995, the
Administrator signed the proposed Hazardous Waste Identification Rule
to revise the mixture and derived-from rules, which was published in
the Federal Register on December 21, 1995. (60 FR 66344).
We received extensive comments, many critical, on the 1995
proposal, particularly with respect to the scientific risk assessment
supporting the proposed revisions to the mixture and derived-from
rules. As a result of the comments, we concluded that considerable work
needed to be done to resolve complex scientific and technical issues
raised by the risk assessment and the comments received. On April 11,
1997, the District Court entered an order amending the consent decree
in Environmental Technology Council v. Browner. The amended decree
provided us with additional time to perform further scientific risk
assessment work and requires us to address specific issues and options
for revising the mixture and derived-from rules. The amended decree
calls for a notice of proposed rulemaking to revise the mixture and
derived-from rules, with an October 31, 1999 deadline for the
Administrator to sign a proposal, and an April 30, 2001 deadline to
sign a notice of final rulemaking. Until this rule is promulgated, the
mixture and derived-from rules are considered to remain in effect on an
``emergency basis.''
C. Why Is EPA Proposing To Retain the Mixture and Derived-From Rules?
The mixture and derived-from rules are necessary to regulate
hazardous wastes in a way that protects human health and the
environment. Mixtures and residuals of hazardous waste represent a
large and varied universe. Many hazardous wastes continue to be toxic
after they have been mixed with other waste or have been treated. As
explained below, without the mixture and derived-from rules, such
wastes could easily escape coverage of RCRA Subtitle C regulations,
while nevertheless posing risks to human health and the environment.
We believe that without the mixture and derived-from rules, some
generators would alter their waste to the point it no longer meets the
listing description without detoxifying, immobilizing, or otherwise
actually treating the waste. For example, without a ``mixture'' rule,
generators of hazardous wastes could escape regulatory requirements by
mixing listed hazardous wastes with other hazardous wastes or
nonhazardous solid wastes to create a ``new'' waste that arguably no
longer meets the listing description, but continues to pose a serious
hazard. Similarly, without a ``derived-from'' rule, hazardous waste
generators could potentially evade regulation by minimally processing
or managing a hazardous waste and claiming that the resulting residue
is no longer the listed waste, despite the continued hazards of the
residue. (See 57 FR 7628). It is therefore necessary for protection of
human health and the environmental to capture mixtures and derivatives
of listed hazardous waste in the universe of regulated hazardous
wastes. A hazardous waste regulatory system that allowed hazardous
waste to leave the system as soon as it was modified to any degree by
being mixed or marginally treated would be ineffective and unworkable.
Such a system could act as a disincentive to adequately treat, store
and dispose of listed hazardous waste.
We know that mixtures and residuals of hazardous waste can be
hazardous based on our experience in identifying and regulating
hazardous waste. For example, during the listing process, we review
data on specific waste streams generated from a number of industrial
processes to determine whether these wastes would pose hazards to human
health or the environment if mismanaged. Through the listing process,
we have determined risks arising from the disposal of waste mixtures
and derived-from wastes. Leachate generated from hazardous wastes is a
particularly good example of residuals of hazardous wastes that contain
toxic chemicals that can endanger environmental or human receptors. Our
risk analyses have shown that multi-source leachate derived from
hazardous waste landfills can contain very high concentrations of toxic
organic compounds and metals. (Preliminary Data Summary for the
Hazardous Waste Treatment Industry, EPA/OW, 1989). Other derived-from
wastes that, because of their treatment process, can result in higher
concentrations of chemicals (especially metals) than their parent
wastes include wastewater treatment sludge and combustor ash. As a
result of either wastewater treatment or combustion, the wastes would
have their volumes greatly reduced, but could still contain the same
amount of inorganic chemicals, thus resulting in a higher concentration
of chemicals.
Our experience with delisting petitions also supports the need to
regulate as hazardous mixtures and residuals of listed hazardous waste
in order to protect human health and the environment. Generators can
petition us under 40 CFR 260.22 to exclude a waste produced at a
particular facility from the definition of hazardous waste. Such
petitions must demonstrate that the waste does not meet any of the
criteria for which it was listed nor has other attributes that might
result in the waste being hazardous. As of March 27, 1995, we have
denied or dismissed 139 of 809 (17%) of delisting petitions received.
This estimate does not include 543 petitions (67% of the total) that
were withdrawn (311), mooted (198) or referred to the State authority
(34). The chief reason for denying or dismissing most of the 139
delisting petitions was failure by the petitioner to supply adequate
information. However, in at least 13 cases, we denied delisting
petitions for mixtures or residuals of listed waste because risk
analyses indicated that the toxicity and leaching potential of
hazardous chemicals in those wastes posed unacceptable risk to human
health (see Disposition of Delisting Petitions for Derived-From/Mixture
Wastes, U.S. EPA memorandum, 1992 and Analysis of the Delisting
Petition Data Management System, U.S. EPA, September 1998). We have
also identified damage cases associated with mixture and derived-from
wastes. For example, there are Superfund sites that contain mixture and
derived-from wastes (See 50 FR 658). In many cases, determining when
the environmental damage occurs on a site is difficult, but we have
identified at least nine sites that involve the mismanagement of
mixture and derived-from wastes. (see ``Releases of Hazardous
Constituents Associated with Mixture and Derived-from Wastes,'' EPA
1999). These waste types are also associated with RCRA corrective
actions where high concentrations of hazardous chemicals were found in
the vicinity of units that contained a listed waste. (Data on Mixture
and Derived-from Wastes from Closures and Corrective Action at
Hazardous Waste Management Facilities, EPA, 1992).
In addition, through the development of the LDR program, we have
considered the appropriateness and effectiveness of various hazardous
waste treatment technologies. Treatments specified within the LDR
regulations, promulgated under 40 CFR 268, are required for hazardous
waste to be land disposed. However, technology-based treatment
standards do not always equate with low risk. In addition, treatment
that is not performed properly or is not fully optimized may result in
residues that present some risk. Further discussion and examples of LDR
treatment are presented in a background

[[Page 63390]]

document entitled Memorandum to the Docket from Larry Rosengrant
Regarding Section 3004(m) of the Hazardous and Solid Waste Amendments,
U.S. EPA January 21, 1992. Since treatment standards are based on the
limits of technology, residuals can still pose sufficient risk to
warrant continued regulation under RCRA Subtitle C.
D. Does EPA Have the Legal Authority To Retain the Mixture and Derived-
From Rules?
We have had, and we continue to have the statutory and regulatory
authority to promulgate the mixture and derived-from rules. The mixture
and derived-from rules, particularly with the revisions proposed today,
ensure that hazardous wastes that are mixed with other wastes or
treated in some fashion do not escape regulation as long as they are
reasonably likely to threaten human health and the environment. These
rules retain jurisdiction over listed hazardous wastes and clarify that
such wastes do not automatically exit the Subtitle C system when they
are mixed or treated, however minimally.
The mixture and derived-from rules are valid exercises of our
authority to list hazardous waste under section 3001 of RCRA. We have
consistently interpreted section 3001(a) as providing EPA with
flexibility in deciding whether to list or identify a waste as
hazardous, that is to consider the need for regulation. Specifically,
section 3001 requires that EPA, in determining whether to list a waste
as hazardous waste, or to otherwise identify a waste as hazardous
waste, decided whether a waste ``should be subject to the requirements
of Subtitle C.'' Hence, section 3001 authorizes us to determine when
Subtitle C regulation is appropriate. The statute directs EPA to
regulate hazardous waste generators (section 3002(a)), hazardous waste
transporters (section 3003(a)), and hazardous waste treatment, storage,
and disposal facilities (section 3004(a)) ``as necessary to protect
human health and the environment.'' By extension, the decision of when
waste should be subject to the regulatory requirements of Subtitle C is
essentially a question of whether regulatory controls promulgated under
sections 3002-3004 are necessary to protect human health and the
environment. We have therefore consistently interpreted section 3001 to
give us broad flexibility in fashioning criteria for hazardous wastes
to enter or exit the Subtitle C regulatory system. See, Military Toxics
Project v. EPA, 146 F.3d 948, 958 (D.C. Cir. 1998).
EPA's 1980 criteria authorize the listing of classes of hazardous
wastes when we have reason to believe that wastes in the class are
typically or frequently hazardous. See 40 CFR 261.11(b). As discussed
Section III.C. above, EPA has ample reasons for classifying mixtures
and residuals of listed hazardous waste as hazardous wastes.
In addition to providing the context in which the determination of
whether a waste ``should be subject to the requirements of Subtitle
C,'' sections 3002-3004 allow us to impose requirements on waste
handlers until wastes have ``cease[d] to pose a hazard to the public.''
Shell Oil Co. v. EPA, 959 F.2d 741, 754 (D.C. Cir. 1991). See also
Chemical Manufacturers Assoc. v. EPA, 959 F.2d 158, 162-65 (D.C. Cir.
1990) (EPA may regulate the disposal of nonhazardous wastes in a
hazardous waste impoundment under section 3004) and Chemical Waste
Management, Inc. v. EPA, 976 F.2d 2, 8, 13-14 (D.C. Cir. 1992) (EPA may
require further treatment of wastes under section 3004 even though they
cease to exhibit a hazardous characteristic).

Proposed Revisions to 40 CFR 261.3

IV. How and Why Is EPA Proposing To Revise the Hazardous Waste
Identification Regulations for Mixtures and Derived-From Wastes?

A. How and Why Is EPA Proposing To Revise the Hazardous Waste
Identification Regulations for Wastes That Were Listed Solely for
Ignitability, Corrosivity and/or Reactivity?
There are 29 waste codes within the RCRA program listed solely for
ignitability, corrosivity, and/or reactivity characteristics.
Currently, 40 CFR 261.3(a)(2)(iii) specifies that a mixture of these
wastes and a solid waste is no longer a hazardous waste if the mixture
does not exhibit a hazardous characteristic. These mixtures must still
meet the LDR requirements of 40 CFR 268.40.
We believe that wastes listed solely because they exhibit the
ignitability, corrosivity and/or reactivity characteristics should all
be treated identically, whether they are mixtures, residuals, or wastes
meeting the original listing description as generated. For example, ash
resulting from the combustion of an ignitable listed waste would no
longer exhibit the characteristic of ignitability. Under the current
derived-from rule, this ash would not be exempt, however if it were a
``mixture'' rather than a treatment residual, it would be exempt under
the current mixture rule. Another example are nitroglycerine patches,
which when used for medical purposes are not reactive even at the point
they are manufactured, but are regulated as P081 when discarded. Thus,
today's proposed revision would expand this exemption which is
currently in the mixture rule only, so that all these materials would
be exempt from hazardous waste regulation if they are de-characterized
and meet the appropriate LDR treatment standards, including treatment
for all underlying hazardous constituents (as defined in 40 CFR
268.3(i)). Table 1 presents the 29 wastes codes and the
characteristic(s) that are the basis for their listing.

Table 1.--Wastes Listed for Ignitability, Corrosivity, and/or Reactivity
------------------------------------------------------------------------
Waste code Description Hazard code
------------------------------------------------------------------------
1............. F003 Spent xylene and other (I)
non-halogenated solvents.
2............. K044 Wastewater treatment (R)
sludges from the
manufacturing and
processing of explosives.
3............. K045 Spent carbon from the (R)
treatment of wastewater
containing explosives.
4............. K047 Pink/red water from TNT (R)
operations.
5............. P009 Ammonium Picrate......... (R)
6............. P081 Nitroglycerine........... (R)
7............. P112 Tetranitromethane........ (R)

[[Page 63391]]

8............. U001 Acetaldehyde............. (I)
9............. U002 Acetone.................. (I)
10............ U008 Acrylic Acid............. (I)
11............ U031 n-Butyl alcohol.......... (I)
12............ U020 Benzenesulfonyl chloride. (C, R)
13............ U055 Cumene................... (I)
14............ U056 Cyclohexane.............. (I)
15............ U057 Cyclohexanone............ (I)
16............ U092 Dimethylamine............ (I)
17............ U096 Cumene Hydroperoxide..... (R)
18............ U110 Di-n-propylamine......... (I)
19............ U112 Ethyl Acetate............ (I)
20............ U113 Ethyl Acrylate........... (I)
21............ U117 Ethyl Ether.............. (I)
22............ U124 Furan.................... (I)
23............ U125 Furfural................. (I)
24............ U154 Methanol................. (I)
25............ U161 Methyl isobutyl ketone... (I)
26............ U186 1,3 Pentadiene........... (I)
27............ U189 Sulfur phosphide......... (R)
28............ U213 Tetrahydrofuran.......... (I)
29............ U239 Xylene................... (I)
------------------------------------------------------------------------
I=ignitability, C=corrosivity, R=reactivity

As explained in Section XXI, the majority of the waste which would
be eligible for this exemption would be F003 (spent xylene and other
non-halogenated solvents). However, the full listing description for
F003 in 40 CFR 261.31 includes the following statement: ``and all spent
solvent mixtures/blends containing, before use, one or more of the
above non-halogenated solvents, and, a total of ten percent or more (by
volume) of one or more of those solvents listed in F001, F002, F004,
and F005 * * *'' Although F003 is listed solely for ignitability, its
listing description includes references to solvents that were listed
for toxicity as well. This is one of the reasons that LDR standards
reference a composite list of chemicals that must be treated for F001,
F002, F003, F004 and F005. We therefore request comment on whether to
allow F003 to be eligible for this proposed exemption.
B. How Is EPA Proposing To Revise The Mixture and Derived-From Rules
for Mixed Waste?
In the revisions to 40 CFR Part 261.3 that we are proposing today,
we also include a conditional exemption for mixed waste from the
mixture and derived-from rules, provided the mixed waste is handled in
accordance with 40 CFR Part 266, Subpart N.
The proposed regulatory language in 40 CFR Part 266, Subpart N,
which we are including in a separate Federal Register notice published
elsewhere today conditionally exempts hazardous waste mixed with low-
level radioactive wastes (low-level mixed wastes/LLMW), or mixed with
Naturally Occurring and/or Accelerator-produced Radioactive Material
(NARM mixed waste) from the storage, treatment in tank, transportation,
and disposal requirements of RCRA. Nuclear Regulatory Commission (NRC)
or its Agreement State licensed LLMW generators can store, or treat
LLMW in storage tanks without RCRA Subtitle C permits if all exemption
conditions are met. Treated LLMW or NARM mixed waste could be disposed
at a low level radioactive waste disposal facility (LLRWDF) regulated
by the NRC or its Agreement State if all exemption conditions are met.
The rationale for conditionally exempting LLMW from the mixture and
derived-from rules is the same as that for creating the conditional
exemption from the RCRA regulatory definition of hazardous waste for
LLMW. We incorporate by reference the notice of proposed rulemaking for
the LLMW conditional exemption (EPA Docket Number F-1999-ML2P-FFFFF).
We request comment on whether to conditionally exempt low level mixed
wastes from the mixture and derived-from rules.

HWIR Exemption Options

V. Why Is EPA Developing a Chemical-Based HWIR Exemption for Listed
Hazardous Waste (Including Both Mixtures and Derived-From Waste)?

A. What Issue Would the HWIR Exemption Address?
The HWIR exemption would refine the regulation of hazardous wastes
by improving identification of lower risk hazardous wastes, while
ensuring that the health of our nation's citizens and environment is
not compromised. Wastes are hazardous and subject to RCRA Subtitle C
regulations if they exhibit certain characteristics (``characteristic
wastes'') or if they have been placed on certain lists by EPA (``listed
wastes'').
Once a waste is identified as a listed hazardous waste, it remains
regulated as hazardous, even if it has been treated to remove all
hazardous chemicals, unless the wastes are formally delisted. Delisting
under 40 CFR 260.22 requires a formal rulemaking process under the
Administrative Procedures Act (APA). Delistings are waste stream
specific, with close government review of sampling procedures,
analytical test results, and the accompanying quality assurance and
quality control (QA/QC) data. This process has the advantage of
tailoring the delisting determination to the specific waste, but it is
also resource intensive and time consuming for both the petitioner and
the government. Such costs could discourage a generator from

[[Page 63392]]

exploring the use of pollution prevention and new waste treatment
technologies to detoxify his waste. By offering a self-implementing
alternative, the HWIR exemption would exempt low-risk wastes more
quickly and at less cost than the current delisting process.
B. How Would the HWIR Exemption Affect the Regulation of Hazardous
Waste?
Under this approach, wastes that have been designated as listed
hazardous wastes under Subpart D of 40 CFR Part 261 (or are mixed with,
derived from, or contain listed hazardous wastes) would no longer be
subject to the full ``cradle to grave'' RCRA Subtitle C hazardous waste
management requirements, if the chemicals of concern in the wastes are
below risk-based exemption levels. The waste would instead be managed
under RCRA Subtitle D nonhazardous waste management requirements, which
better match the risks posed by this low-risk waste. The HWIR approach
would be self-implementing, and therefore less burdensome both to the
generator and the overseeing agency than the current delisting process.
C. How Would the Exemption Continue To Ensure Protection of Human
Health and the Environment?
HWIR would continue to ensure protection of human health and the
environment by establishing numerical risk levels that are based on a
multi-media approach to environmental protection. The risk models that
would underlie the exemption levels in the HWIR exemption predict the
potential release of hazardous chemicals from waste management units to
the air, land, surface water, and groundwater. If wastes contain these
chemicals at concentrations greater than these levels, they would
remain regulated as hazardous under RCRA Subtitle C. On the other hand,
those wastes that no longer contain these chemicals or that can be
demonstrated to contain these chemicals below these levels, would no
longer be considered hazardous under RCRA Subtitle C, but would still
be subject to State nonhazardous waste regulations. The HWIR exemption
would also include testing and documentation requirements to ensure
that the exemption levels have been and continue to be met.

VI. What Options Is EPA Developing for the HWIR Exemption?

We are developing two options for the HWIR exemption: (1) The
``generic'' HWIR exemption, and (2) the ``landfill-only'' HWIR
exemption. As discussed in Section XVII of this preamble, we are not
proposing the HWIR exemption because of technical difficulties in
developing chemical-specific exemption levels from the model. Before we
would promulgate an HWIR exemption, we would first publish an HWIR
proposal that would include specific exemption levels and give the
public an opportunity to comment. Therefore, our discussion consists of
a ``framework'' for the two HWIR exemption options. In this discussion,
``you'' refers to the person who would wish to claim an exemption for a
waste under these options.
A. What Is the Generic HWIR Exemption option?
Under the generic HWIR exemption option, your listed hazardous
waste would no longer be hazardous once the risk-based exemption levels
have been satisfied, and you fulfill the conditions and requirements
discussed in Section IX of this preamble. The exemption levels would be
listed in a new appendix to 40 CFR Part 261 (Appendix X), found in
Table 2, in Section XIV of this preamble. You would have to continue to
meet specific waste testing requirements to ensure that the waste
remains below the HWIR exemption levels.
This option is based on the premise that the HWIR exemption levels
would be protective in all reasonable waste disposal scenarios.
Therefore, there would be no limits to where an HWIR waste could be
disposed under this option, except for existing State requirements that
apply to all nonhazardous industrial wastes. A discussion of the risk
assessment model supporting this option can be found in Sections XV
through XIX of today's preamble.
B. What Is the Landfill-Only HWIR Exemption?
Under the landfill-only HWIR exemption, your waste would have to
meet a different set of HWIR exemption levels, found in Table 2, in
Section XIV of this preamble, and you would be required to dispose of
the waste in a landfill. A landfill is a land-based unit where non-
liquid wastes are placed for permanent disposal, and is not a land
application unit (where wastes are incorporated into the soil). This
landfill would not need to be a hazardous waste landfill, but
nonhazardous landfills are still regulated under existing State
requirements, which would help ensure that it is protective of human
health and the environment. This landfill disposal requirement is in
addition to the other requirements described under the generic HWIR
exemption option.
In addition, under the landfill-only exemption, you would also be
required to fulfill waste tracking requirements to ensure that the
waste does arrive at a landfill, and until the waste is disposed, you
would not be allowed to place it on the land. We are concerned about
the temporary placement of these wastes in waste piles or other such
intermediate land-based destinations, because exemption levels for the
landfill-only option (unlike the levels for the generic option) would
not consider such risks. See Section XII of this preamble for
discussion of these additional conditions and requirements.
We believe that restricting wastes to landfills and customizing the
exemption levels to that unit focuses the HWIR exemption on the lowest-
risk and most likely disposal scenario for non-liquids. Management in a
landfill helps reduce air release and overland transport of hazardous
chemicals. This option could allow for less conservative exemption
levels, thus reducing regulatory costs while continuing to protect
human health and the environment.
C. What Implementation Options Are in Both the 1995 HWIR Proposal and
Today's Notice?
In our 1995 HWIR proposal, we developed a number of options for
exempting low risk wastes from RCRA Subtitle C hazardous waste
regulation. Under a proposed ``base national option,'' generators would
be required to demonstrate that constituent concentrations within a
waste did not exceed risk-based HWIR exemption levels. Conceptually,
the base national option from 1995 is the same as today's generic
option discussed in Section VI.A of this preamble. We also proposed
several ``contingent management'' options, under which generators were
required to meet alternate exemption levels, provided that they met
additional waste management requirements. The landfill-only option
discussed in Section VI.B of this preamble is similar to one of the
contingent management options proposed in 1995.
When we developed today's notice, we considered all of the options
discussed or proposed in 1995, plus an additional contingent management
option that would require waste to be stabilized and then disposed in a
landfill. (see Evaluation of Contingent Management Options, U.S. EPA,
1999). One of the most pervasive comments on the 1995 HWIR proposal was
related to the number and complexity of alternatives, which made it
difficult for readers to understand and comment on the proposal. We
have decided to

[[Page 63393]]

develop only the two options we have deemed most viable: the base
national option and the contingent management national option 1
(disposal in a landfill). As discussed above, these two options are
called the generic HWIR option and the landfill-only HWIR option.
The 1999 HWIR options differ from their 1995 counterparts. The
biggest changes are to the risk assessment we are developing to support
the options. Instead of modeling each exposure pathway separately as we
did in 1995, the current version of the model takes into account
simultaneous exposures via multiple pathways. See Sections XV through
XIX of this preamble for a discussion of the current version of the
model. In the 1995 HWIR proposal we included more than 350 exemption
levels. About half of these levels were based on risk modeling, while
the other have were based on an extrapolation methodology that we have
since discarded. As explained in Section XVII, today's discussion does
not include any specific exemption levels because of technical
difficulties in the risk modeling. Instead, we discuss the framework of
the exemption and ask for comment on the modeling approach. Before we
would promulgate an HWIR exemption, we would first publish an HWIR
proposal that would include specific exemption levels and give the
public an opportunity to comment.
In addition to modeling changes, we have also revised the
discussion of some of the implementation requirements. We have scaled
back the testing requirements so that facilities would not have to
document why chemicals would not be in their waste (essentially proving
a negative). Instead, under today's options, facilities would only have
to test for chemicals ``reasonably expected'' to be in their waste; the
guidelines for determining what chemicals we would ``reasonably
expect'' to be in a waste are discussed in Section IX of this preamble.
Also, for the generic option, we have developed three categories of
wastes (liquids, semi-solids, and solids) rather than the two proposed
in 1995 (wastewaters and nonwastewaters). These categories are
discussed in more detail in Section XIX.C. Finally, for the landfill-
only option, we would require tracking requirements to ensure that the
waste arrives at its intended destination. These requirements are
discussed in Section XII.B.
D. Why Did We Decide Not To Go Forward With Two of the National
Contingent Management Approaches Discussed in the 1995 HWIR Proposal?
The 1995 HWIR options included three approaches that required a
generator to meet national exemption levels. After carefully evaluating
these options and reviewing the input we received from our
stakeholders, we determined that, except for the landfill-only national
contingent management option (analogous to the first national
contingent management option from 1995), it would not be feasible and/
or desirable to develop and implement the other approaches at this
time.
Under the second national contingent management option for 1995
HWIR proposal, we considered establishing exemption levels for each
type of waste management unit: landfill, waste pile, land application
unit, tank, and surface impoundment. Upon further review, however, we
determined that setting exemption levels for waste piles, land
application units, tanks or surface impoundments was not a desirable
option for several reasons.
First, waste piles and tanks are intermediate disposal
destinations. It is not appropriate to exempt wastes based on exposures
from just these units and no others, since the final disposition of the
waste is most important for determining long-term risk. Second, we
found in 1995 that the land application unit drove most of the non-
liquid exemption levels and therefore separate land application unit
levels would be no different from levels established for the generic
option. Similarly, a surface impoundment option would be expected to be
similar to levels for liquids established under the generic option, and
we do not believe that separate exemption levels are warranted. Given
that the generic option has fewer requirements and similar exemption
levels, we decided a contingent management option for land application
units and surface impoundments would add unnecessary complexity to the
rule.
Under the third national contingent management option, we
considered setting exemption levels for waste management units with
specific design or operating controls that would allow for less
conservative exemption levels. Although specific public comment on the
national contingent management options was limited, representatives
from industry indicated a support for options that allowed the
consideration of site-specific factors. Therefore, in addition to
evaluating the approach of developing separate exemption levels for
each type of waste management unit, we considered developing exemption
levels based upon engineering controls in place at certain units.
However, when we evaluated the unit control option, we found it
difficult to quantitatively attribute a set of risk protection levels
to specific engineering and management controls, especially over a long
period of time. Also, in order to enforce such an option, we would need
to make complex judgements regarding whether the required unit controls
were being used correctly. Such determinations would be more
appropriately made under the oversight of a permitting authority,
rather than as a condition of a self-implementing exemption under HWIR.
E. Why Did We Decide Not To Go Forward With the State Contingent
Management Approaches Discussed in the 1995 HWIR proposal?
In 1995, we proposed that qualified States would be allowed to
manage listed waste in their nonhazardous waste management programs
under certain conditions. We included three different State-based
approaches. These three approaches differed in terms of (1) the risk-
based criteria (10-5 versus 10-4 cancer risk, for
example) that would be used to identify the set of wastes that could be
managed under an approved State program; (2) the type of State program
review that we would conduct to identify qualified State programs
(qualitative and/or quantitative); and (3) the breadth of the State
program that we would review and qualify. For example, we could have
reviewed the entire State nonhazardous program, or only that portion
related to the HWIR exemption.
As we considered the above State program approaches to contingent
management, we recognized that State industrial nonhazardous waste
programs have improved significantly since the early days of the RCRA
Subtitle C hazardous waste program. A well-developed State program
could offer a continuum of management for waste of varying risks and
allow more local judgements and ongoing oversight of HWIR exemptions.
Waste generators have also expressed support for State program
approaches to contingent management, because site-specific or regional
specific parameters could be considered to a larger extent in State
risk assessments. However, after further consideration of the State
program options, as well as review of the input we received from our
stakeholders, we decided that the implementation of these options would
be difficult.
Although the States recognize that relying upon State programs
could be a

[[Page 63394]]

preferable alternative for the regulated community than a national
approach (in terms of less conservative exemption levels for example),
they expressed concern about resource implications, should they be
required to independently develop exemption criteria. The States would
have to perform risk assessments, which are resource-intensive and
require specialized expertise. From an implementation perspective, some
States would prefer for EPA to develop exemption levels for the States
to implement and enforce within their Subtitle D versus Subtitle C
programs. (see Overview: State-Based Contingent Management Case Study
Project, Discussion Draft for April 1-2, 1998 Joint ASTSWMO Task Force
Meeting, March 9, 1998).
Furthermore, the transfer of jurisdiction over HWIR-exempt wastes
from the Federal to the State governments would entail some type of EPA
review of the quality of State Subtitle D programs. One State
association indicated it would be inappropriate for EPA to evaluate
State Subtitle D programs as part of authorizing states to use the
contingent management options.
Finally, State program approaches would result in a variety of
disposal standards across the States. States and the regulated
community would have to devote additional resources to ensure that
waste streams generated and exiting under contingent management
standards in neighboring States meet applicable transportation and
disposal standards in the receiving States. A representative of the
waste management industry expressed concern over the interstate
transport ramifications of these approaches. For these reasons, we have
decided not to pursue a State contingent management implementation
option.
F. What Other HWIR Implementation Option Has EPA Considered?
We also considered another contingent management option which would
establish HWIR exemption levels for stabilized wastes when managed in a
landfill. This approach was based upon the notion that different risks
are posed by the same chemicals in different waste forms. More
specifically, the physical nature of stabilized wastes, their ability
to reduce the mobility of chemicals in the environment and the
requirement to manage such waste in a landfill could provide additional
protection. For example, stabilizing the waste and managing it in a
landfill would help reduce or eliminate certain releases, such as
windblown dust. By taking this additional protection into account, we
could develop specific exemption levels that would be less stringent
than those developed for the national generic option or the landfill-
only option, but equally protective. The focus on stabilized waste
forms was partially derived from a screening study that has been placed
in the docket (see Waste Forms Technical Background Document, U.S. EPA,
September 1998).
As explained in the background document, we decided not to further
develop a stabilized waste option because of complications in defining
which stabilized forms are appropriate and technical difficulties in
determining what are the appropriate reductions in mobility from these
forms.

VII. What Wastes Would Be Eligible for an HWIR Exemption?

A listed hazardous waste would be eligible for this exemption once
all the HWIR exemption levels are achieved. Even though the wastes
might still contain chemicals for which they were originally listed,
concentrations at HWIR exemption levels would pose very low risk to
human health and the environment. However, wastes which exhibit any of
the hazardous characteristics would continue to be regulated as
hazardous wastes until the characteristic is removed, even if HWIR
exemption levels are achieved.
As discussed in Section XVIII of this preamble, we might not
develop HWIR exemption levels for all ``chemicals of concern'' (HWIR
exemption chemicals). Those wastes that would reasonably be expected to
contain HWIR exemption chemicals without exemption levels would not be
eligible for the exemption even if those chemicals are not detected in
the waste. Chemicals can pose risk below levels capable of being
detected by analytical methods. If a chemical does not have a risk-
based HWIR level to compare against, we cannot evaluate whether it
poses a risk below detection. Therefore, we believe that any waste that
would be reasonably expected to contain an HWIR exemption chemical that
does not have an exemption level should be ineligible for the HWIR
exemption, regardless of test results. See Section IX.A for further
discussion of this issue.

VIII. What Level of Governmental Review Would Be Needed for an HWIR
Exemption Claim?

For both the generic and the landfill-only alternatives, the HWIR
exemption would be self-implementing. Self-implementing means that no
prior governmental approval or review of documentation is required
before wastes are exempted from RCRA hazardous waste regulation. The
use of a self-implementing mechanism is consistent with most other
hazardous waste exemptions and exclusions, such as exemptions from the
mixture and derived-from rules found in 40 CFR 261.3(c)(2)(ii) and
exclusions from the definition of hazardous waste found in 40 CFR
261.4(b).
Self-implementation has several advantages: (1) The exemption can
take effect quickly, (2) the generator's burden in claiming the
exemption is reduced, and (3) the burden for the overseeing agency (the
authorized State or an EPA Region) is also reduced. Most of the
commenters to the 1995 HWIR proposal, including a majority of States,
favored self-implementation.
Self-implementation would not prevent the overseeing agency from
having a role in the HWIR exemption. As a condition of claiming an HWIR
exemption, you would be required to provide specific information to the
overseeing agency (see Section IX.D). In addition, you would be
required to keep and retain records in order to maintain an exemption
(see Section XI.C). This information would be available to the
overseeing agency in an inspection and for an enforcement action, if
needed. Because HWIR waste would be some of the lowest-risk industrial
wastes, and the overseeing agency would still have authority to enforce
against an improperly claimed exemption, we believe that there would be
little benefit to requiring prior governmental approval before the
exemption takes place.
In addition, your waste would only become exempt upon your
receiving written confirmation that the notification package had been
received by the overseeing agency. Examples of confirmation include
certified mail return receipt, or written confirmation of delivery from
a commercial delivery service. Upon receipt that the notification
package has been delivered successfully, you would be allowed to manage
the HWIR waste as nonhazardous. Confirmation that the overseeing agency
has received the package would not imply, however, that the package has
been reviewed or approved.
As noted above, since our preferred option is to make the HWIR
exemption self-implementing, the overseeing agency would not be
required to make a decision regarding the waste prior to exemption. We
do not believe that requiring a waiting period (for example, 30 or 60
days) before the exemption becomes effective is necessary. Most of the
commenters to the 1995 HWIR

[[Page 63395]]

proposal, including representatives of industry, federal and state
government agencies, utility associations, industry associations and
waste management associations opposed the idea of a waiting period.
They felt that such a waiting period could create undue expense,
administrative burden, and numerous legal and practical complications
(such as storage space issues).
Some of the commenters on the 1995 HWIR proposal, including some
State governments, favored having the option of requiring prior
approval and a waiting period. One possible approach would to require a
waiting period which could be used by the overseeing authority to
review the notification package. This review would be discretionary. If
the overseeing authority takes no action during this waiting period,
then the exemption would be approved. Commenters on the 1995 HWIR
proposal who favored a waiting period felt that it would allow the
overseeing agency time to screen notifications and obtain additional
information as necessary. Waiting period recommendations ranged from 30
days to 90 days.
We request comment on whether HWIR should be self-implementing, and
whether there should be a waiting period before the exemption take
effect.

IX. For the Generic HWIR Exemption, What Steps Would I Follow Before My
Waste Could Be Exempted?

You would be required to complete the following steps before your
waste could be exempted:
(a) Determine which HWIR exemption chemicals of concern your waste
is reasonably expected to contain. (see Section IX.A below)
(b) Develop a waste sampling and analysis plan (see Section
IX.B.1).
(c) Determine that the concentrations of the chemicals reasonably
expected to be present in your waste are at or below the appropriate
exemption levels (see Section IX.B.1).
(d) Determine that the waste does not exhibit any of the hazardous
waste characteristics of Subpart C of 261.
(e) Notify the overseeing agency that you are claiming an exemption
under this Subpart for your waste (see Section IX.D).
Once you receive confirmation that your notification was received
by the overseeing agency, then your waste is exempt. Figure 1 provides
an overview of this process, which is described in more detail in the
sections that follow.

BILLING CODE 6560-50-P

[[Page 63396]]

[GRAPHIC] [TIFF OMITTED] TP19NO99.000

BILLING CODE 6560-50-C

[[Page 63397]]

A. For Which Chemicals Would I Have To Analyze To Obtain an HWIR
Exemption?
To claim the HWIR exemption for your candidate waste (``HWIR
waste''), you would have to determine for which chemicals listed in the
new 40 CFR Part 261 Appendix X (found in Table 2, in Section XIV of
this preamble) you would have to analyze. You would have to test your
HWIR waste for all chemicals reasonably expected to be present, which
includes the following:
1. Chemicals identified as the basis for listing the waste. (For F
and K listed waste, these chemicals are found in Appendix VII of 40 CFR
261. For P and U listed waste, these are the chemicals named in the
specific listings found in 40 CFR 261.33);
2. Chemicals listed in the table ``Treatment Standards for
Hazardous Wastes'' contained in 40 CFR 268.40 as regulated hazardous
chemicals for LDR treatment of the waste;
3. Chemicals detected in any previous analysis of the waste;
4. Chemicals introduced into the process that generates the waste;
and
5. Chemicals that are known to result from side reactions or are
byproducts of the process that generates the waste.
You would not be required to test for every chemical found in the
new 40 CFR Part 261 Appendix X (which contains the broad set of
chemicals ``of concern'' discussed in XVII.A of this preamble). You
could use process knowledge to determine if a chemical other than those
included in the five categories referenced above might be present in
the waste. If you were to determine that the chemical is not reasonably
expected to be present in the waste, you do not need to test for it.
However, you would be responsible for ensuring that the waste meets all
HWIR exemption levels. If at any time the waste fails to meet the
levels, then the waste stream is not exempt. Additionally, you would be
also responsible for determining whether your waste exhibits one of the
hazardous waste characteristics set out in Subpart C of part 261.
We request comment on the above guidance for determining which
chemicals are ``reasonably expected to be present.'' In particular, we
request comment on whether and how to adjust this definition for some
of the broader waste listings, such as electroplating operations (RCRA
waste code F006) or spent solvents (RCRA waste codes F001-F005). These
listings represent multiple processes, and any particular process would
not necessarily contain all the chemicals for which the broad waste
code was listed. For example, a chrome plating waste might not
necessarily contain nickel, even though nickel is one of the chemicals
associated with F006 wastes.
In addition, as discussed in Section XVII of this preamble, we
might not develop exemption levels for all HWIR chemicals. If your
waste would reasonably be expected to contain HWIR exemption chemicals
that do not have levels, that waste would not be eligible for the
exemption even if that chemical is not detected in your waste. The
reason we believe that such wastes should be ineligible is that
chemicals can pose risk below analytical method detection limits.
If a chemical does not have a risk-based HWIR level to compare
against, we cannot evaluate whether a waste poses a risk below its
analytical detection limit. Therefore, any waste that would be
reasonably expected to contain an HWIR chemical that does not have an
exemption level would not be exempted, regardless of test results.
Unlike the 1995 HWIR proposal, under this approach you would only be
required to test chemicals that are or have historically been
associated with the waste (either through the original listing, the LDR
requirements, or generator knowledge). Therefore, we believe it is
reasonable that for those chemicals, an absence of a risk-based
standard would prevent the associated waste from becoming exempt.
We did not encounter this issue in our 1995 HWIR proposal because
we assigned every chemical an exemption level either through modeling
or through an extrapolation methodology. We have subsequently discarded
the extrapolation methodology because both the public comments and our
own internal review indicated that it did not have a firm enough
scientific basis. We request comment on this policy to exclude from
HWIR eligibility those wastes are reasonably expected to contain
chemicals that do not have HWIR exemption levels.
B. How Would I Have To Sample and Analyze My Waste Stream When Seeking
an Exemption Under HWIR?
Under today's approach, you would have to sample and analyze for
all chemicals that you determined are reasonably expected to be present
in your waste stream. In addition to the initial testing described
below, you would also be required to retest your waste stream after it
is exempted to ensure ongoing compliance. It remains your
responsibility to ensure that a waste stream always meets the exemption
requirements for all HWIR exemption chemicals, regardless of which
chemicals you would be required to test, how many samples you consider,
or how often you retest.
The discussion that follows explores, in some depth, a number of
issues related to the characterization of your waste stream and the
determination of compliance with the HWIR exemption's testing
requirements. For each waste stream that you seek to exempt, you would
have to develop and follow a written plan for sampling and analyzing
your waste stream. This plan is discussed in Section IX.B.1. You must
analyze at least four samples and must document the results from all
samples analyzed. Waste stream characterization and appropriate methods
are discussed in the remaining parts of Section IX.B. For every
chemical tested, each sample must show that the total concentration is
at or below the exemption level. This standard of compliance is
discussed in Section IX.B.2. Possible alternatives to this standard of
compliance are discussed in Section IX.C. Together, these elements form
the core testing requirements for a generator initially seeking
exemption. Subsequent testing requirements and the frequency of such
testing are discussed later in Section XI.A of this preamble.
1. Waste sampling and analysis plan. The waste sampling and
analysis plan is a planning document used to define the necessary
criteria and quality control requirements for sampling, analysis, and
data assessment. We recommend that these plans be developed consistent
with the guidance provided in the applicable sections of ``Test Methods
for Evaluating Solid Waste, Physical/Chemical Methods'' (SW-846). More
specifically, chapters within this document that should be helpful to
you include Chapter One that describes basic quality assurance and
quality control procedures, Chapter Nine which provides guidance on
sampling strategy, and sampling techniques, and Chapter Two that
identifies appropriate methods for samples based upon sample matrix and
the analytes to be analyzed.
You would be required to develop a waste sampling and analysis plan
prior to testing your hazardous waste stream for compliance with the
HWIR exemption levels. Your waste sampling and analysis plan would be
required to contain the following information:
a. The chemicals for which each waste stream will be analyzed and
the rationale for the selection of those chemicals;
b. Sampling strategy, and methods used to obtain representative
samples of the waste stream to be analyzed;
c. The sample preparation, clean-up, if necessary, and test
determinative

[[Page 63398]]

methods used to analyze for these chemicals; and
d. Sufficient sampling procedures and locations to characterize the
entire waste stream.
You might already have a waste sampling and analysis plan in place
because of general facility standards for treatment, storage or
disposal facilities (see 40 CFR 264.13 and 265.13), or because of land
disposal requirements (see 40 CFR 268.7(a)). The key elements of an
HWIR waste sampling and analysis plan are consistent with these other
waste analysis plans (See Waste Analysis at Facilities that Generate,
Treat, Store and Dispose of Hazardous Waste, U.S. EPA April 1994). You
can create a separate waste sampling and analysis plan for your HWIR
exemption or you could modify existing plans to fulfill both HWIR and
LDR requirements. Be aware that a modification to your existing waste
sampling and analysis plan could require a permit modification.
2. Waste stream characterization and demonstration of compliance
with the HWIR exemption levels. You would have to obtain representative
samples and analyze your waste stream to ensure that it is properly
characterized. Such samples should be collected in an unbiased manner,
that is, one which gives all samples an equal chance of appearing to
represent the population. Analysis of such samples should statistically
represent concentrations in the waste stream in terms of averages and
variation. Finally, such samples should preserve the waste's
composition and to prevent contamination or changes in concentration of
the parameters to be analyzed.
You would also have to evaluate your waste stream using the maximum
detected concentrations based upon the complete extraction of HWIR
exemption chemicals. If any sample contains a chemical at a
concentration greater than its specified exemption level, then the
waste stream would be ineligible for the HWIR exemption.
The specific exemption levels your waste must meet depend on the
regulatory option under which you seek to exempt your waste (generic
and landfill-only options). The two regulatory options, which are
discussed in Section VI, would have separate exemption levels. In
addition, the different waste form categories within the generic option
(liquid, semi-solid, solid) would have separate exemption levels. (See
Section XIX.C for a discussion of this waste form categories). The
format of the exemption levels table is presented in Table 3 found in
Section XIV of this preamble. Meeting the appropriate exemption level
requires that the concentration of each sample be at or below that
exemption level.
Because any sample above the HWIR exemption levels would disqualify
the waste stream from the exemption, this could provide an incentive to
take as few samples as possible. To have adequate confidence that the
waste stream is properly exempt, today's approach would require a
minimum number of samples. In constructing this requirement, we do not
want to overprescribe sampling in cases in which you seek to exempt a
homogeneous waste stream whose true average concentrations are
substantially below the exemption level.
We believe that a minimum of four samples at each testing event is
reasonable. This minimum number of samples conforms to the requirements
developed for the delisting program and established in its guidance
(see Petitions to Delist Hazardous Wastes: A Guidance Manual, U.S. EPA
March 1993). In addition, at least four samples are often used to
characterize your waste stream using common statistical measures of
average concentration (sample mean) and variability (standard
deviation), and can be used to determine if additional samples are
appropriate.
This minimum number of samples should not be assumed to be the same
as an appropriate number of samples. The appropriate number of samples
should be consistent with the characterization of the waste stream and
the distribution of concentrations recorded as a result of the samples
taken. As specific requirements for the HWIR exemption, you would have
to take at least four samples and to characterize your waste stream.
The number of samples you would have to take would have to be
sufficient to represent variability throughout the waste stream and
across time. We recognize that solid wastes are often not homogeneous
and are by nature generally heterogeneous. Solids are also frequently
difficult to completely mix. Thus, more than four samples might be
needed. You should use your knowledge of the process generating the
waste stream to help determine the appropriate number of samples. The
greater the variability within the waste, the more difficult it is to
determine whether your samples are representative of the entire waste
stream. One way to improve sampling precision is to increase the number
of samples. In addition, you can improve your information on the
variability of chemical concentrations within the waste stream by
analyzing grab samples.
Because generators of many different kinds of waste streams might
seek exemption under HWIR, we have no preconceived notions on how
variable your particular waste stream might be. Sampling of a
heterogeneous waste with highly variable concentrations would require a
greater number of samples, as contrasted with relatively homogeneous
wastes with mean concentrations well below the exemption levels. In
addition, the longer the time period over which you might need to
establish the variability of the waste stream, the greater the number
of samples you should take. For waste streams that experience wide
variability in chemical concentrations over time, you should discuss,
in your waste sampling and analysis plan, how your sampling strategy
addresses such variability.
You still would continue to be responsible for ensuring that your
waste streams always meet the appropriate exemption levels. We discuss,
in a background document, estimates regarding numbers of samples. This
document explores sample sizes for different waste streams, for the
not-to-exceed compliance standard (the preferred approach) as well as
alternative compliance standards discussed later under subsection C of
this part of the preamble (see Estimates of Sample Sizes Required for a
Generator to Demonstrate a Waste Qualifies for Exemption Under HWIR,
U.S. EPA, May 1999).
We request comment on both the need for a minimum number of samples
and what that minimum number should be.
Allowing no samples to exceed the HWIR exemption level provides a
clear standard against which both you and the overseeing authority can
refer for compliance and enforcement purposes. Such clarity is
especially important in the context of a self-implementing regulatory
mechanism, because the overseeing agency would not scrutinize the waste
sampling and analysis plan in advance to determine if such
methodologies were chosen and applied correctly.
As noted in the 1995 HWIR proposal, enforcement authorities prefer
the practicality of a strict maximum standard. Inspectors seek to
independently collect samples for analysis over a short time span. An
exceedance by any sample during an inspection could constitute a
violation.
In some cases, you might also be required to demonstrate compliance
with LDR sampling and analysis requirements. For example, wastes that
become exempt after the point they are generated would have to still
fulfill LDR requirements. To demonstrate

[[Page 63399]]

compliance for the LDR program, ``all portions of the waste must meet
the applicable treatment standards, that is, no portion may exceed the
regulatory limit.'' (63 FR 28556, 28567 (May 26, 1998)). Thus requiring
that all samples be at or below the exemption levels would be
consistent with the approach used in the LDR program.
We recognize limitations to the strict maximum standard. As noted
by commenters to the 1995 proposal, you would have to effectively meet
a much lower average concentration level to maintain confidence that no
sample would exceed the HWIR exemption level. However, as the purpose
of HWIR is to exempt only waste streams that are clearly nonhazardous,
imposing a strict maximum makes continued compliance more certain for
wastes with chemical concentrations far below the exemption levels.
Wastes with chemical concentrations near the exemption level,
especially wastes with some significant degree of variability, may not
be the most appropriate candidates for a self-implementing HWIR
exemption.
However, unlike the development of the LDR regulatory standards and
its implementation of a strict maximum, the HWIR model as designed
would not incorporate variability into the exemption levels. Within the
LDR standards, we set a maximum acceptable chemical level for a
particular waste treatability group, based on the performance of the
Best Demonstrated Available Technologies (BDAT). This maximum
incorporates fluctuations in performance for well-designed and well-
operated treatment systems and thereby ``builds in'' variability into
the standard itself. This maximum is calculated as the mean of
individual performance values multiplied by variability and recovery
factors.
In developing LDR concentration based treatment standards, we did
not believe that incorporating variability relaxed the requirements of
Section 3004(m), but rather represented a response to ``normal
variations in treatment processes. As a practical matter, facilities
will have to incorporate variability factors into process design to
ensure performance that is more stringent than the standard to ensure
continuous compliance with the standard.'' (see BDAT Background
Document for QA/QC Procedures and Methodology dated October 23, 1991).
In contrast, for the purposes of the HWIR exemption levels, there were
no data or estimates of concentration variability within wastes.
Therefore, adjustments to the HWIR exemption levels would not have the
same informational basis available for incorporating variability into
the regulatory standard.
We request comment on the strict maximum standard against which to
evaluate a waste stream for an HWIR exemption. Alternatives to the
strict maximum are discussed in Section IX.C below.
3. Selection of a reliable analytical method to test your waste
stream. We would not specify which method you would use to evaluate
chemical concentrations in waste; you may select any reliable
analytical method. However, you would have to establish and document
that the performance of the selected method demonstrates that the HWIR
exemption level was achieved.
You would also have to demonstrate that the analysis could have
detected the presence of a chemical at or below the specified exemption
level. We would consider that the HWIR exemption level was achieved if
you indicate that the chemical concentration of a spiked sample is at
or below some fraction of the exemption level within analytical method
performance limits (for example, sensitivity, bias and precision). To
determine the performance limits for a method, we recommend following
the quality control (QC) guidance provided in Chapters One and Two of
SW-846, and the additional QC guidance provided in the individual
methods. As discussed in the 1995 HWIR proposal, detection at, but not
below, the exemption level may not be sufficient to establish a
reliable method, because such detection would not demonstrate the
absence of the chemical with sufficient confidence (60 FR 66377). At a
method's limit of quantitation, results may be obtained with a specific
degree of confidence, generally with an uncertainty of plus or minus
30% in the measured value (see Keith, L.H., Environmental Sampling: A
Practical Guide, 1992). The relative uncertainty would be expected to
be much lower as the concentrations increase above a method's
quantitation limit. Again, quality control guidance found within SW-846
and associated with the individual methods should assist in identifying
the necessary performance.
Your method would also have to attain acceptable recovery for the
chemicals under analysis. Such recovery is dependent upon the waste
matrix being analyzed and has ranged from 80-120% for method
development activities, volatile organics (using relative recoveries),
and for inorganics in almost all matrices. Analyses of certain other
chemicals (extractable organics) can achieve slightly smaller
recoveries (70%+), and for a few ``difficult'' matrices, we have
considered sample preparation appropriate if it generates recovery of
50% or greater. These issues are discussed within a recent Agency
memorandum (see Appropriate Selection and Performance of Analytical
Methods for Waste Matrices Considered to be `Difficult to Analyze',
U.S. EPA memorandum, January, 1996). In the development of LDRs,
methods with less than 20 percent recovery have been discarded from the
calculation of treatment standards (see BDAT Background Document for
QA/QC Procedures and Methodology, U.S. EPA, October 23, 1991).
If you have trouble meeting these acceptable levels of recovery,
you may be using an inappropriate method, may not have pursued
appropriate alternative methods (consistent with guidance on method
modification), or may be faced with the lack of an existing, validated
method. In the case in which an existing method or appropriate
alternative will not achieve acceptable recoveries, we request comment
on correcting such analyses for the bias introduced by these
deficiencies in recovery. Bias introduced by partial recoveries refers
to the systematic deviation of analytical results due to matrix
effects. It can be assessed by comparing measurements to an accepted
reference value in a sample of known concentration or by determining
the recovery of a known amount of contaminant spiked into a sample
(that is, a matrix spike). Given the potential for using different
methods, adjustments with respect to recovery can make the results from
different methods more comparable.
We specifically request comment on the option of requiring that
analytical protocols achieve a minimum of 20% recovery, and that
analytical results with analytical spike recovery of less than 100% be
corrected for the percent recovery determined for that waste before
being compared to the HWIR exemption level. This adjustment would allow
the greatest flexibility in the choice of analytical procedures,
provide equivalency between different procedures, and allow those
matrices that are difficult to analyze to be considered for exemption.
Finally, we seek to address potential technical limitations of
analytical methods in quantitating to concentrations identified through
the HWIR risk modeling. In the 1995 HWIR proposal, we suggested the use
of detection limits to serve as exemption levels in cases where the
exemption

[[Page 63400]]

levels fell below proposed ``exemption quantitation criteria'' or EQCs.
Such EQCs were defined as the lowest levels that can be reliably
measured within acceptable limits of precision and accuracy during
routine laboratory operating conditions using appropriate methods (60
FR 66377). For chemicals that had modeled or extrapolated levels below
their EQCs, we set the exemption level for these chemicals at the EQC
and required the application of LDR treatment standards, regardless of
whether the waste was to be land disposed. We also discussed the
alternative of making wastes containing chemicals with analytical
limitations ineligible for an exemption, but expressed concerns about
the impact such a policy would have on eligible waste volumes.
We continue to harbor concerns about the impact that technical
limitations might have on waste eligibility, but are equally interested
in creating continuing incentives for generators to improve their
analytical methods and quantitate to levels selected on the basis of
risk. We have historically noted and continue to recognize increased
sensitivity of analytical methods over time. Levels of quantitation are
also driven by market demands, and by setting exemption levels on the
outer reaches of current methods, we seek to have the market modify and
develop methods to reach these levels. Commenters to the 1995 rule
encouraged the continued pursuit of analytical methods, possibly
through revisiting such EQC determinations over time.
We are also interested in bolstering the relationship of the
exemption levels to the underlying risk assessment and therefore, seek
to avoid the adoption of levels not related to risk; established
quantitation levels (for example, EQCs) and LDR treatment standards are
not based on risk assessment and therefore are not ideal for
identifying HWIR waste as non-hazardous. Therefore, in seeking
exemption under HWIR, you would have to use and modify, as necessary,
reliable analytical methods to determine if concentrations in your
waste meet the exemption levels.
In 1995, we received comments both supporting our application of
EQCs as exemption levels and rejecting such usage as not associated
with risk. Under another alternative, we could use the detection limit
in place of the risk-based level, if the risk associated with the
detection level concentration is judged to be within an acceptable
range of risk (even if not meeting the primary risk objectives). We
request comment on the option of using the detection limit in place of
the HWIR exemption level when the detection limit is higher, but still
within an acceptable level of risk.
C. What Alternatives Has EPA Considered for Demonstrating Compliance
With the Exemption Levels?
1. EPA requests comment on alternative standards for compliance. As
explained previously, we would require all samples to have
concentrations at or below the HWIR exemption level. However, we did
consider alternative standards for compliance. These alternative
standards would allow the mean chemical concentration within the HWIR
waste to be closer, yet still at or below the HWIR exemption level.
Such alternatives would allow greater variability in sample
concentrations near the exemption level and, to a modest extent, allow
chemical concentrations from individual samples to exceed the HWIR
exemption level, while maintaining the mean to be below the exemption
level.
We believe that it might be appropriate to consider alternatives
that would allow chemical concentrations from individual samples to
exceed the HWIR exemption level because of the nature of the risk
assessment used to set those levels. The HWIR risk assessment considers
only chronic risk. Therefore, the levels are based on average exposure
to a chemical over a lifetime, not on one-time events. In addition, the
current version of the risk modeling does not consider variations in
waste concentrations within a calendar year.
Specifically, we request comment on three alternative regulatory
standards: (1) The upper confidence limit associated with the estimated
mean concentration in the waste would have to be at or below the HWIR
exemption level at some level of confidence; (2) the estimated mean
chemical concentration within the candidate waste would have to be at
or below the HWIR exemption levels, and the concentration of individual
samples would be required to be at or below some multiple of the
exemption level; and (3) the estimated mean concentration would have to
be at or below the HWIR exemption level, and the upper confidence limit
associated with the estimated mean (at some level of confidence) would
have to be at or below some multiple of the exemption level.
Within the upper confidence level approach under alternative (1),
you would have to demonstrate that the upper confidence limit around
the estimated mean concentration in the waste is below the HWIR
exemption level at some specified level of confidence. This approach
was used in the comparable fuels rule which required the upper
confidence limit at 95% confidence to be below the exclusion level (see
63 FR 33782).
An upper confidence limit approach has advantages in that it allows
for a degree of variation in the concentration of individual samples in
the waste. The mean would be required to be below the HWIR exemption
levels; however, occasional values above the exemption level would be
tolerated. The approach is self-implementing in the determination of
the number of samples required and it is consistent with the way RCRA
wastes are often assessed for the toxicity characteristic.
An upper confidence limit approach also provides continuing
incentives to better characterize the wastes. Within the strict maximum
approach, the more samples you take, the greater the likelihood that
one sample would fail. With an upper confidence limit approach, the
more samples that you take, the better that you can establish the upper
confidence limit associated with the mean (that is, the more precise
your estimate is of the mean). With an upper confidence limit approach,
wastes with mean concentrations near but below the exemption level
could be exempted by taking enough samples to bring the upper
confidence limit below the exemption level. You would need to determine
whether the value of the exemption justifies the cost of sampling.
Specifically requiring a minimum number of samples is unnecessary
with an upper confidence limit approach. The number of samples is
directly calculable from the confidence level chosen, the standard
deviation of the distribution, and the distance between the mean and
the exemption levels.
An upper confidence limit would provide the maximum flexibility in
selecting the sampling, analytical and statistical methods for
establishing an HWIR exemption. Although an upper confidence limit is a
statistically based performance criterion, that does not mean you would
have to perform a large number of chemical analyses nor employ complex
statistics.
However, we are concerned about prescribing statistical methods for
evaluation of HWIR compliance. Inspectors would still have the right to
enforce based on grab samples, and inspectors would find it difficult
and resource intensive to replicate the type of sampling needed to
construct a statistically based upper confidence limit. Therefore,
disagreements between you as the generator and inspectors could
engender involved statistical comparisons as well as increased costs in
resolving compliance status.

[[Page 63401]]

The second alternative requires both the average chemical
concentration to be below the HWIR exemption levels, and the
concentration of individual samples to be below some multiple of the
exemption level. Requiring all individual samples to be below a
multiple of the exemption level restricts the potential variability of
the waste. Only wastes with modest variation (and/or the ability to
maintain lower average levels) are likely to meet HWIR exemption
levels.
Consistent with the no exceedance approach, a minimum number of
samples would need to be required under this alternative. There would
be a similar incentive not to test your waste, because the more samples
you take, the greater the probability of finding an individual sample
that would fail.
This alternative could be of benefit to both you and enforcement
officials. Enforcement officials would have one concentration level
against which to evaluate compliance, and you would have a standard
that would tolerate some variation in the waste around the exemption
level and permit individual samples to exceed the exemption level.
Making assumptions about the underlying distribution and ranges of
waste stream concentrations and adopting the same approach that we used
to develop variability factors under the LDR program, we suggest a
multiple for this evaluative standard

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A99-29067. Public record. Not legal advice.