[Federal Register Volume 82, Number 12 (Thursday, January 19, 2017)]
[Proposed Rules]
[Pages 7562-7580]
[FR Doc No: 2017-01224]

Vol. 82

Thursday,

No. 12

January 19, 2017

Part XVII

 Environmental Protection Agency

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40 CFR Part 702

 Procedures for Chemical Risk Evaluation Under the Amended Toxic
Substances Control Act; Proposed Rule

Federal Register / Vol. 82 , No. 12 / Thursday, January 19, 2017 /
Proposed Rules

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 702

[EPA-HQ-OPPT-2016-0654; FRL-9957-75]
RIN 2070-AK20

Procedures for Chemical Risk Evaluation Under the Amended Toxic
Substances Control Act

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: As required under section 6(b)(4) of the Toxic Substances
Control Act (TSCA), EPA is proposing to establish a process for
conducting risk evaluations to determine whether a chemical substance
presents an unreasonable risk of injury to health or the environment,
without consideration of costs or other non-risk factors, including an
unreasonable risk to a potentially exposed or susceptible
subpopulation, under the conditions of use. Risk evaluation is the
second step, after Prioritization, in a new process of existing
chemical substance review and management established under recent
amendments to TSCA. This proposed rule identifies the steps of a risk
evaluation process including scope, hazard assessment, exposure
assessment, risk characterization, and finally a risk determination.
EPA is proposing that this process be used for the first ten chemical
substances to be evaluated from the 2014 update of the TSCA Work Plan
for Chemical Assessments, chemical substances designated as High-
Priority Substances during the prioritization process, and those
chemical substances for which EPA has initiated a risk evaluation in
response to manufacturer requests. The proposed rule also includes the
required ``form and criteria'' applicable to such manufacturer
requests.

DATES: Comments must be received on or before March 20, 2017.

ADDRESSES: Submit your comments, identified by docket identification
(ID) number EPA-HQ-OPPT-2016-0654, by one of the following methods:
     Federal eRulemaking Portal: http://www.regulations.gov.
Follow the online instructions for submitting comments. Do not submit
electronically any information you consider to be Confidential Business
Information (CBI) or other information whose disclosure is restricted
by statute.
     Mail: Document Control Office (7407M), Office of Pollution
Prevention and Toxics (OPPT), Environmental Protection Agency, 1200
Pennsylvania Ave. NW., Washington, DC 20460-0001.
     Hand Delivery: To make special arrangements for hand
delivery or delivery of boxed information, please follow the
instructions at http://www.epa.gov/dockets/contacts.html.
    Additional instructions on commenting or visiting the docket, along
with more information about dockets generally, is available at http://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT:
    For technical information contact: Susanna W. Blair, Immediate
Office, Office of Pollution Prevention and Toxics, Environmental
Protection Agency, 1200 Pennsylvania Ave. NW., Washington, DC 20460-
0001; telephone number:<PHONE_NUMBER>; email address:
<EMAIL_ADDRESS>    For general information contact: The TSCA-Hotline, ABVI-Goodwill,
422 South Clinton Ave., Rochester, NY 14620; telephone number: (202)
554-1404; email address<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

I. Executive Summary

A. Does this action apply to me?

    EPA is primarily proposing to establish requirements on the Agency.
However this proposal also includes the process and requirements that
manufacturers (including importers) would be required to follow when
they request an Agency-conducted risk evaluation on a particular
chemical substance. This action may, therefore, be of interest to
entities that are manufacturing or importing, or may manufacture or
import a chemical substance regulated under TSCA (e.g., entities
identified under North American Industrial Classification System
(NAICS) codes 325 and 324110). Since other entities may also be
interested, the Agency has not attempted to describe all the specific
entities and corresponding NAICS codes for entities that may be
interested in or affected by this action.

B. What action is the agency taking?

    EPA is proposing to establish the process by which the Agency would
conduct risk evaluations on chemical substances under TSCA. The
proposal identifies the necessary components of a risk evaluation,
including a scope (composed of a conceptual model and an analysis
plan), a hazard assessment, an exposure assessment, a risk
characterization, and a risk determination. The proposed rule would
also establish the process by which manufacturers (including importers)
would request an Agency-conducted risk evaluation, and the criteria by
which the EPA would evaluate such requests.

C. What is the agency's authority for taking this action?

    EPA is proposing this rule pursuant to the authority in TSCA
section 6(b)(4), as amended (15 U.S.C. 2605(b)). See also the
discussion in Units II.A. and B.

D. What are the estimated incremental impacts of this action?

    Although this proposal focuses on the process and activities that
apply to EPA, it also proposes the process and requirements that
manufacturers (including importers) would be required to follow when
they request an Agency-conducted risk evaluation on a particular
chemical substance. Since these requirements qualify as an information
collection under the Paperwork Reduction Act (PRA), 44 U.S.C. 3501 et
seq., EPA has prepared an Information Collection Request (ICR) to
estimate the potential burden and costs associated with the proposed
requirements for submitting a request for an Agency-conducted risk
evaluation on a particular chemical substance. The ICR, which is
available in the docket, is discussed in Unit VI.B. and is briefly
summarized here. (Ref. 1).
    The total estimated annual burden is 960.3 hours and $69,353, which
is based on an estimated per request burden of 96.03 hours.

E. What should I consider as I prepare my comments for EPA?

    1. Submitting CBI. Do not submit this information to EPA through
regulations.gov or email. Clearly mark the part or all of the
information that you claim to be CBI. For CBI information in a disk or
CD-ROM that you mail to EPA, mark the outside of the disk or CD-ROM as
CBI and then identify electronically within the disk or CD-ROM the
specific information that is claimed as CBI. In addition to one
complete version of the comment that includes information claimed as
CBI, a copy of the comment that does not contain the information
claimed as CBI must be submitted for inclusion in the public docket.
Information so marked will not be disclosed except in accordance with
procedures set forth in 40 CFR part 2.
    2. Tips for preparing your comments. When preparing and submitting
your comments, see the commenting tips at http://www.epa.gov/dockets.

II. Background

A. Recent Amendments to TSCA

    On June 22, 2016, the President signed into law the ``Frank R.
Lautenberg Chemical Safety for the 21st Century Act,'' which imposed
sweeping reforms to TSCA. The bill received broad bipartisan support in
the U.S. House of Representatives and Senate, and its passage was
heralded as the most significant update to an environmental law in over
20 years. The amendments give EPA improved authority to take actions to
protect people and the environment from the effects of dangerous
chemical substances. Additional information on the new law is available
on EPA's Web site at: https://www.epa.gov/assessing-and-managing-chemicals-under-tsca/frank-r-lautenberg-chemical-safety-21st-century-act.
    When TSCA was originally enacted in 1976, it established an EPA-
administered health and safety review process for new chemical
substances prior to allowing their entry into the marketplace. However,
tens of thousands of chemical substances in existence at that time were
``grandfathered in'' with no requirement for EPA to ever evaluate their
risks to health or the environment. The absence of a review requirement
or deadlines for action, coupled with a burdensome statutory standard
for taking risk management action on existing chemical substances,
resulted in very few chemical substances ever being assessed for safety
by EPA, and even fewer subject to restrictions to address identified
risks.
    One of the key features of the new law is the requirement that EPA
now systematically prioritize and assess existing chemicals, and manage
identified risks. Through a combination of new authorities, a risk-
based safety standard, deadlines for action, and minimum throughput
requirements, TSCA effectively creates a ``pipeline'' by which EPA will
conduct existing chemicals review and management. This new pipeline--
from prioritization to risk evaluation to risk management (when
warranted)--is intended to drive steady forward progress on the backlog
of existing chemical substances left largely unaddressed by the
original law. Risk evaluation is the second step of this process, after
prioritization, which is being addressed in a separate rulemaking.

B. Statutory Requirements for Risk Evaluation

    TSCA section 6(b)(4) requires EPA to establish, by rule, a process
to conduct risk evaluations. Specifically, EPA is directed to use this
process to ``determine whether a chemical substance presents an
unreasonable risk of injury to health or the environment, without
consideration of costs or other non-risk factors, including an
unreasonable risk to a potentially exposed or susceptible subpopulation
identified as relevant to the risk evaluation by the Administrator
under the conditions of use.'' (15 U.S.C. 2605(b)(4)(A)). TSCA sections
6(b)(4)(A) through (H) enumerate the deadlines and minimum requirements
applicable to this process, including provisions that direct which
chemical substances must undergo evaluation, the development of
criteria for manufacturer-requested evaluations, the minimum components
of an Agency risk evaluation, and the timelines for public comment and
ultimate completion of the risk evaluation.
    1. Chemical substances to undergo risk evaluation. TSCA section
6(b) identifies the chemical substances that are subject to this
process; these are: (1) Ten chemical substances the Agency is required
to identify from the 2014 update to the TSCA Work Plan within the first
180 calendar days after the signing of TSCA (15 U.S.C. 2605(b)(2)); (2)
the chemical substances determined as High-Priority Substances through
the prioritization process that is being proposed in a separate
rulemaking; and (3) requested chemicals submitted by manufacturers that
have met the criteria for EPA to conduct a risk evaluation as outlined
by this rule. Assuming a sufficient number of requests that have met
the criteria outlined in this proposed rule are received, subsection
(E) specifies that the number of manufacturer-requested evaluations be
25 to 50 percent of the number of ``High Priority'' risk evaluations
ongoing at any one time. Since the number of manufacturer-requested
evaluations is expressed as a percentage of the number of High-Priority
Substance evaluations, not as a percentage of the total, the number of
manufacturer-requested evaluations will likely comprise between 1/5 and
1/3 of the number of total ongoing evaluations, assuming a sufficient
number of compliant requests are received. Any manufacturer requested
chemical substances on the 2014 update of the TSCA Work Plan (Ref. 2)
are exempt from the percentage limitations.
    2. Manufacturer-requested risk evaluations. TSCA section 6(b)(4)(C)
directs EPA to establish the ``form and manner'' and ``criteria'' that
govern manufacturer requests that a substance that they manufacture
undergo an EPA conducted risk evaluation. EPA has broad discretion to
establish these criteria, but relatively less discretion over whether
to grant requests that comply with EPA's criteria. EPA must grant any
request that complies with EPA's criteria, until the statutory minimum
of 25 percent has been met. Assuming EPA receives requests in excess of
this threshold, EPA interprets this provision to grant EPA discretion
to determine whether to grant further requests, up to the maximum 50
percent level. In such circumstances, the EPA is directed to give
preference to manufacturer requests for which the EPA determines that
restrictions imposed by one or more states have the potential to
significantly impact interstate commerce, or health or the environment.
15 U.S.C. 2605(b)(4)(E)(iii). As discussed elsewhere in this preamble,
EPA is also proposing to give preference to requests where EPA
estimates there may be relatively high exposure(s) and/or hazard(s)
under one or more conditions of use.
    3. Components of a risk evaluation. The statute identifies the
minimum components EPA must include in all chemical substance risk
evaluations. For each risk evaluation, EPA must publish a document that
outlines the scope of the risk evaluation that will be conducted, and
that includes the hazards, exposures, conditions of use, and the
potentially exposed or susceptible subpopulations the EPA expects to
consider. 15 U.S.C 2605(b)(4)(D). The statute provides that the scope
of the risk evaluation must be published no later than six months after
the initiation of the risk evaluation.
    Each risk evaluation must also: (1) ``integrate and assess
available information on hazards and exposure for the conditions of use
of the chemical substance, including information on specific risks of
injury to health or the environment and information on potentially
exposed or susceptible subpopulations;'' (2) ``describe whether
aggregate or sentinel exposures were considered and the basis for that
consideration;'' (3) ``take into account, where relevant, the likely
duration, intensity, frequency, and number of exposures under the
conditions of use;'' (4) ``describe the weight of scientific evidence
for the identified hazards and exposure.'' 15 U.S.C.
2605(b)(4)(F)(i),(iii)-(v). The risk evaluation must not consider costs
or other non-risk factors. 15 U.S.C. 2605(b)(4)(F)(ii).
    Many stakeholders have expressed concern as to how EPA will apply
``weight of scientific evidence'' under

the amended TSCA. EPA is providing, for the purposes of background, a
description of how the Agency has consistently interpreted and applied
that concept. EPA is not proposing to modify this process as part of
this rule. Nor is EPA proposing to codify it; this process has and will
continue to evolve with changing scientific methods and innovation.
Codifying a specific definition can inhibit the flexibility of the
Agency to quickly adopt and implement changing science.
    The phrase weight-of-evidence (WoE) is used by EPA and other
scientific bodies to describe the strength of the scientific inferences
that can be drawn from a given body of evidence, specifically referring
to how studies are selected, the quality of the studies evaluated, and
how findings are assessed and integrated. Weight-of-evidence is a
complex issue and as stated by the National Academies this is ``because
scientific evidence used in WOE evaluations varies greatly among
chemicals and other hazardous agents in type, quantity, and quality, it
is not possible to describe the WoE evaluation in other than relatively
general terms. It is thus not unexpected that WoE judgements in
particular cases can vary among experts and that consensus is sometimes
difficult to achieve'' (NAS, 2009) (Ref. 3). The following is a brief
description of how WoE is used at EPA, serving as an example of
successful application of WOE in making the scientific determinations.
    EPA utilizes the WoE approach in existing programs including IRIS
and the Endocrine Disruptor Screening Program among others, and in the
classification of carcinogens. In the 1999 Guidelines for Carcinogen
Risk Assessment (Ref. 4) EPA refers to the WoE approach as ``. . . a
collective evaluation of all pertinent information so that the full
impact of biological plausibility and coherence is adequately
considered (Ref. 5). The Endocrine Disruptor Screening and Testing
Advisory Committee (EDSTAC) referred to the WoE approach as ``. . . a
process by which trained professionals judge the strengths and
weaknesses of a collection of information to render an overall
conclusion that may not be evident from consideration of the individual
data'' (Ref. 6).
    WoE is the process for characterizing the extent to which the
available data support a hypothesis that an agent causes a particular
effect (Ref. 4 and 5). This process involves a number of steps starting
with assembling the relevant data, evaluating that data for quality and
relevance, followed by an integration of the different lines of
evidence to support conclusions concerning a property of the substance.
WoE is not a simple tallying of the number of positive and negative
studies, but rather it relies on professional judgment. The significant
issues, strengths, and limitations of the data and the uncertainties
that deserve serious consideration are presented, and the major points
of interpretation are highlighted.
    This WoE analysis is conducted on a case-by-case basis by first
assembling and assessing the individual lines of evidence and then
performing an integrated analysis of those lines of evidence. All data
considered in the WoE analysis need to be documented and scientifically
acceptable. A WoE analysis typically begins with a careful evaluation
of each individual study. The process of evaluating the individual
lines of evidence includes assembling the data, evaluating that data
against current acceptance and quality criteria, and presenting the
conclusions regarding the results for each study. The reviews of the
available studies need to be transparent about what studies were
considered or not, and how the quality of a study was judged.
    After assembling and assessing the individual lines of data, an
integrated analysis is performed. This means the results from all
scientifically relevant published or publically available peer-reviewed
studies, which are of sufficient quality and reliability, are evaluated
across studies and endpoints into an overall assessment. In general,
the WoE analysis examines multiple lines of evidence considering a
number of factors, including for example the nature of the effects
within and across studies, including number, type, and severity/
magnitude of effects and strengths and limitations of the information.
    A summary WoE narrative or characterization generally accompanies
the detailed analysis of the individual studies and the integrative
analysis of the multiple lines of evidence. Inclusion of a WoE
narrative is common in WoE assessments and judgments (Ref. 4 and 7).
The narrative/characterization is intended to be transparent and allow
the reader to clearly understand the reasoning behind the conclusions.
The narrative will generally explain the selection of the studies or
effects used as the main lines of evidence and relevant basis for
conclusions. The overall strength of the evidence supporting a
conclusion from the WoE evaluation needs to be described.
    The National Toxicology Program of the National Institute of
Environmental Health Sciences has developed a tool called ``systematic
review'' to assist in WoE evaluations particularly for hazard
identification (https://ntp.niehs.nih.gov/pubhealth/hat/noms/index-2.html). This tool uses a defined set of processes to identify, select,
critically assess, and synthesize evidence to arrive at a hazard
conclusion for a chemical. It is designed to enhance transparency and
informs scientific judgments. The evidence synthesis step involves
considering factors that decrease confidence in the body of evidence
for a particular health endpoint (e.g. risk of bias, inconsistencies
across studies, imprecision) as well as factors that increase
confidence (e.g. magnitude of the effect, residual confounding,
consistency). By evaluating study design (e.g., consistent with study
guidelines issued by OECD, and test guidelines issued by the Office of
Chemical Safety and Pollution Prevention), and study quality (e.g.,
studies that comply with Good Laboratory Practices (GLP) like those
applicable generally (https://www.federalregister.gov/documents/2016/08/24/2016-19875/good-laboratory-practice-for-nonclinical-laboratory-studies) and those issued by EPA for studies submitted under TSCA and
FIFRA (https://www.epa.gov/compliance/good-laboratory-practices-standards-compliance-monitoring-program)), and integrating negative
data (and consideration of the quality of those data), the confidence
in hazard conclusions can be increased.
    The NIEHS systematic review tool is one example of a documented
systematic review approach. EPA believes the proposed risk evaluation
process generally reflects the use of systematic review approaches that
are appropriate for the types and quantity of information used in a
chemical risk evaluation. EPA requests comment on this view. EPA is
also requesting comment on the need for regulatory text requiring the
use of specific elements of a systematic review approach for hazard
identification, including the appropriateness of specific elements that
might be included and/or concerns about codifying such an approach.
    4. Timeframe. TSCA requires that the risk evaluation process last
no longer than three years with a possible six-month extension. 15
U.S.C. 2605(b)(4)(G).
    5. Opportunities for public participation. The statute requires
that the Agency allow for at least one 30 day public comment period on
the draft risk evaluation, prior to publishing a final risk evaluation.
15 U.S.C. 2605(b)(4)(H).
    6. Metals and metal compounds. When evaluating metals or metal
compounds, EPA must ``use'' the March

2007 Framework for Metals Risk Assessment of the Office of the Science
Advisor (Ref. 8) or a successor document that addresses metals risk
assessment and is peer-reviewed by the Science Advisory Board.
    7. Other statutory requirements. TSCA imposes new requirements on
EPA in a number of different areas that EPA is not proposing to
incorporate or otherwise address in this proposed rule. For example,
amendments to TSCA section 4 require EPA to ``. . . reduce and replace,
to the extent practicable, [. . .] the use of vertebrate animals in the
testing of chemical substances . . .'' and to develop a strategic plan
to promote such alternative test methods. 15 U.S.C. 2603(h). Likewise,
TSCA section 26 requires, to the extent that EPA makes a decision based
on science under TSCA sections 4, 5, or 6, that EPA uses certain
scientific standards and bases those decisions on the weight of the
scientific evidence. 15 U.S.C. 2625(h) and (i). While these
requirements are relevant to the risk evaluation of chemical
substances, EPA is not obliged to repeat them in this proposed rule. As
statutory requirements, they apply to EPA's decisions under TSCA
section 6. Moreover, in contrast to TSCA section 6, Congress has not
directed EPA to implement these other requirements ``by rule;'' it is
well-established that where Congress has declined to require
rulemaking, the implementing agency has complete discretion to
determine the appropriate method by which to implement those
provisions.

C. EPA Risk Assessment

    Since EPA's inception, human health and ecological risk assessment
has informed decisions made to protect humans and the environment. Risk
assessments performed by the Agency inform a broad range of regulatory
decisions, and, over time, the scientific approaches and methods
employed for these risk assessments have evolved. In developing and
refining risk assessment processes, frameworks, and guidance documents,
EPA has incorporated recommendations from expert technical panels,
internal and external peer reviews, and a number of influential reports
from the National Academy of Sciences (NAS) National Research Council
(NRC) including Risk Assessment in the Federal Government (1983) (Ref.
9), Science and Judgement in Risk Assessment. (1994) (Ref. 10),
Understanding Risk: Informing Decisions in a Democratic Society (1996)
(Ref. 11), Toxicity Testing in the 21st Century: A Vision and a
Strategy (2007) (Ref. 12), Phthalates and Cumulative Risk Assessment:
The Tasks Ahead (2008) (Ref. 8), and Science and Decisions: Advancing
Risk Assessment (2009) (Ref. 3). Specifically, the NAS NRC Science and
Decisions Report (Ref. 3) recommended that EPA focus on the important
roles of scoping or problem formulation so that a risk assessment will
serve a specific and documented purpose. An additional recommendation
encouraged EPA to develop risk assessments that are well-tailored to
the problems and decisions at hand so that they can inform the
decision-making process in the most meaningful way. EPA has evaluated,
and will continue to evaluate chemical risks in a manner that is best
suited for the particular chemical substance, including its
manufacture, processing, formulation, uses, and disposal, and the
evaluations may vary as necessary to best characterize potential risks
related to the chemical substance under review.
    As stated, TSCA requires EPA to evaluate risk to relevant
potentially exposed or susceptible subpopulations identified by EPA as
relevant to the risk evaluation under the conditions of use. 15 U.S.C.
2605(b)(4)(A). Although this was added as a component of the newly
amended law, this will not be a new consideration for the Agency; for
example, see EPA's Policy on Evaluating Health Risks to Children (1995)
(Ref. 14). The Agency has evaluated the risk of chemical substances to
all sectors of the population, with particular attention to workers,
indigenous peoples, pregnant women, children, infants, the elderly,
environmental justice communities, and fence-line communities, among
others. The Agency utilizes a number of existing guidance documents
(including but not limited to Ref. 15, 16, 17, 18, and 19) to evaluate
risk at various life stages, and will use and refine these processes to
protect the most vulnerable.
    1. Differences between previous EPA risk assessments under TSCA and
proposed new risk evaluations. In this proposed rule, EPA does not
propose a new method of risk evaluation, but builds upon existing and
proven methodologies for evaluating risk. Also as required by the
statute, the rule includes opportunities for public participation,
statutory deadlines, necessary components of a risk evaluation, and
methods for manufacturer requested risk evaluation. Above and beyond
the statute, the proposed rule provides an additional opportunity for
public participation, added detail as to components of the scope,
hazard and exposure assessments, risk characterization, and increases
transparency in the risk evaluation process. EPA requests comment on
whether and how the proposed rule could provide additional
transparency, public accountability, opportunities for public
participation, or incorporation of statutory deadlines.
    There are several key differences between previous chemical risk
assessments conducted under TSCA and the new risk evaluation process
mandated by TSCA amendments and established under these proposed
regulations. These differences include considerations of conditions of
use, timelines, and determination of unreasonable risk, and are
discussed in more detail under those topics in this unit. This proposed
rule and procedures described herein apply to risk evaluations
conducted under TSCA, and do not apply to risk evaluations conducted by
EPA pursuant to other statutes or programs.
    2. Conditions of use. Prior to the amended TSCA, EPA was free to
and did conduct risk assessments on selected uses of chemical
substances. In contrast, EPA interprets the amended TSCA as requiring
that risk evaluations encompass all manufacture, processing,
distribution in commerce, use, and disposal activities that constitute
the conditions of use within the meaning of TSCA section 3. That is to
say, a risk evaluation must encompass all known, intended, and
reasonably foreseen activities associated with the subject chemical
substance. This issue has been the subject of considerable discussion
since the enactment of the new law, and EPA acknowledges that different
readings of the law may be possible. For example, TSCA section
6(b)(4)(D) requires EPA to identify the conditions of use that the
Agency expects to consider in a risk evaluation, suggesting that EPA
does not need to consider all conditions of use.
    Overall, the statutory text and purpose are best effectuated
through a more encompassing reading. TSCA section 6(b)(4)(A) specifies
that a risk evaluation must determine whether ``a chemical substance''
presents an unreasonable risk of injury to health or the environment
``under the conditions of use.'' The evaluation is on the chemical
substance--not individual conditions of use--and it must be based on
``the conditions of use.'' In this context, EPA believes the word
``the'' is best interpreted as calling for evaluation that considers
all conditions of use. First, if EPA were free to base its
determination of whether a chemical substance, as a whole, presents an
unreasonable risk or injury (as the statute requires) on merely a
subset of individual uses, it could, for example,

determine that a chemical substance with 10 known uses does not present
an unreasonable risk of injury based on an evaluation of a single one
of those uses, with no further obligation to evaluate the remaining
uses within the three-year statutory deadline. This is a strained
reading of the commands to determine whether the chemical substance
presents an unreasonable risk, under the conditions of use, and to
complete that evaluation ``for a chemical substance'' within three
years of initiation. See 15 U.S.C (b)(4)(G)(i).
    Second, a major objective of the new law is to require EPA to
systematically evaluate existing chemical substances to determine
whether or not they present unreasonable risk, and, if necessary,
regulate them based on the results of the evaluation. Given the large
number of existing chemical substances, it would not be feasible to
complete risk evaluations on any significant number of them if EPA were
to continually need to re-evaluate chemical substances based on
different subset of uses. Rather the law's purposes will be best
fulfilled by judging in a comprehensive way whether a chemical
substance, under the known, intended, and reasonably foreseen uses and
other activities, presents an unreasonable risk; ensuring through
regulation that it does not present an unreasonable risk, if necessary;
and then presumptively being done with that chemical substance (pending
re-prioritization for some unforeseen reason). Finally, EPA notes that,
if the law is read as allowing EPA to select particular conditions of
use, it provides no criteria for EPA to apply in making such a
selection.
    Given these considerations, the instruction in TSCA section
6(b)(4)(D) for the Agency to identify the conditions of use it expects
to consider in a risk evaluation is best read as directing the Agency
to identify the uses and other activities that it has determined
constitute the conditions of use, not as a license to choose among
conditions of use.
    Concerns have been raised about EPA's ability to meet the statutory
risk evaluation deadlines if all conditions of use must be considered.
Concerns have also been raised about ensuring that EPA can act promptly
to address any unreasonable risks identified for particular conditions
of use. EPA acknowledges that this will be challenging but based on the
procedures outlined in this proposal, expects it will be manageable.
First, a use or other activity constitutes a condition of use under the
definition only if EPA determines that it does. EPA has authority to
exercise judgment in making its determination of whether a condition of
use is known, intended, or reasonably foreseen. Moreover, in this
proposed rule EPA proposes to ``lock down'' the conditions of use
included in a risk evaluation at the time of scoping, by providing
opportunity for comment on the scoping document and specifying that any
objections to the draft scope document are waived if not raised during
this process. It will not be practicable to meet the statutory
deadlines if stakeholders are free to identify additional conditions of
use later in the process--for example, on the proposed risk
determination.
    As explained elsewhere in this preamble, EPA also generally intends
to initiate risk evaluation on a chemical substance only when EPA
determines that sufficient reasonably available information exists to
complete the evaluation, and when it has already identified all of the
conditions of use. As also explained elsewhere in this preamble, under
certain circumstances EPA may expedite an evaluation for a particular
condition of use to move more rapidly to risk management under TSCA
section 6(a).
    Finally, the proposed rule provides that EPA will rely on a
combination of information, accepted science policies (e.g., defaults
and uncertainty factors), models and screening methodologies in
conducting risk evaluations, with considerations of evolving science
and technology. It further provides that the balance of information,
science policy decisions, models, and screening methodologies used in
risk evaluation will be informed by the deadlines specified in TSCA
section 6(b)(4)(G) for completing such evaluations, and by the extent
to which the generation of additional information is warranted by the
reduction in uncertainty that the information would afford in
determining whether a chemical substance presents an unreasonable risk
of injury to health or the environment.
    In this regard, EPA is also proposing to require that the
components of its risk evaluations will be ``fit for purpose.'' All
conditions of use will not warrant the same level of evaluation, and
EPA expects it may be able to reach conclusions without extensive or
quantitative evaluations of risk. For example, lower-volume or less
dispersive uses might receive less quantitative, data-driven
evaluations than uses with more extensive or complicated exposure
patterns. Consistent with EPA's current practice in conducting risk
assessments, technically sound risk determinations can be made,
consistent with the best available science, through a combination of
different types of information and other approaches.
    In sum, Congress intended to create obligations that EPA can
actually meet, and EPA intends to conduct risk evaluations in a way
that is manageable given the statutory deadlines.
    3. Timelines and guidance regarding assessing risks of existing
chemical substances. Prior to the amended TSCA, EPA was not required to
evaluate or manage the risk of the thousands of existing chemical
substances grandfathered in under the 1976 Act. As discussed
previously, the amended TSCA affirmatively requires EPA to evaluate
existing chemical substances more quickly, instructs EPA on how many of
these chemical substances the Agency must evaluate at any given time,
and places time limits on when these evaluations must be completed. 15
U.S.C. 2605(b)(2)-(4).
    4. Determination of unreasonable risk. Under TSCA section 6(b) (15
U.S.C. 2605(b)(4)(B)), EPA must establish a risk evaluation process to
determine whether a chemical substance presents an unreasonable risk of
injury to health or the environment. Prior to the passage of the
amended TSCA, chemical substance risk assessments did not include a
determination of unreasonable risk. This step was reserved for risk
management rulemaking. The amended statute now requires that a risk
evaluation include a risk assessment as well as the EPA's determination
of unreasonable risk, and, most significantly, requires that this
determination be independent of cost or other non-risk factors. 15
U.S.C. 2506(b)(4)(A) and (F)(iii).
    In general, EPA may weigh a variety of factors in determining
unreasonable risk. These factors include, but are not limited to,
characterization of cancer and non-cancer risks (including margins of
exposure for non-cancer risks), the population exposed (including any
susceptible populations), the severity of hazard (the nature of the
hazard), the irreversibility of hazard, uncertainties, and estimates of
cumulative exposure. Because of the case-by-case nature of each of
these factors EPA has purposely not proposed a definition of
unreasonable risk in this rule. However, EPA is specifically requesting
comments on whether EPA should define unreasonable risk in the final
rule. If so, acknowledging that the statute precludes consideration of
costs and other non-risk factors at this step, what factors should EPA
consider in making such a determination?
    5. Manufacturer-requested evaluations and draft risk evaluations by
interested persons. The newly

amended TSCA requires that a portion of ongoing risk evaluations be
conducted on chemical substances requested by manufacturers ``in a form
and manner and using criteria'' EPA prescribes by rule. 15 U.S.C.
2605(b)(4)(C)(ii),(E)(i). The statute also requires EPA to develop
guidance (which will be forthcoming) to assist interested persons in
submitting draft risk evaluations, and requires EPA to consider such
submitted drafts. 15 U.S.C. 2625(l)(5).

D. Stakeholder Feedback

    On August 9, 2016, EPA held a one-day public meeting to obtain
public comment and feedback regarding the development and
implementation of the risk evaluation rule. The meeting began with an
explanation of how the Agency currently conducts risk assessments (see
https://www.epa.gov/sites/production/files/2016-08/documents/risk_evaluation_9_august_2016.pdf). The remainder of the day was
reserved for public comment. Each commenter was provided four minutes
to comment and there was a total of 47 oral comments on the risk
evaluation rule. Additionally, EPA opened a docket for submission of
written comments and received 57 comments, many of which were from the
same commenters at the public meeting. These comments, and a transcript
of the meeting are accessible in the meeting's docket, identified by
Docket ID No. EPA-HQ-OPPT-2016-0399, which is available online at
https://www.regulations.gov/.
    The commenters included industry, environmental groups, academics,
private citizens, trade associations, and health care interest groups
and representatives. The comments were very informative for both rule
development and risk evaluation implementation. While not all of the
comments are captured here, there were a number of themes that emerged.
Overall, there was a general expression of support for the new law and
EPA's inclusive approach to implementation. Many of the commenters
agreed the rule has the potential to increase transparency in EPA's
chemical substance risk evaluation process. Many urged the Agency to
work towards this goal, while creating an open scientific dialogue.
    Questions arose about how the Agency will determine ``unreasonable
risk'' and implement TSCA section 26 requirements including ``best
available science'' and ``weight of scientific evidence.'' Some
suggested that EPA should codify in this rule the meaning of these
terms along with other details of the risk evaluation process. Due to
changes in the law, manufacturers are now able to submit their own
draft risk evaluations. Commenters noted that if these submitted
evaluations are to be equivalent as Agency draft risk evaluations,
having specific criteria, such as specific types of exposure and hazard
information would ensure the Agency and the manufacturers were held to
the same standard. Stakeholders also suggested that holding a public
comment period for the draft risk evaluation scope would increase the
transparency of each risk evaluation early in the process and allow the
public to comment on any data gaps or discrepancies.
    Other stakeholders urged the Agency to reserve specific scientific
processes regarding hazard and exposure information for Agency guidance
and discretion, suggesting the rule should address only the process and
procedure. This approach would allow the Agency to be flexible and
adapt to the changing science of risk evaluation and the science that
informs risk evaluation.
    A number of commenters spoke about the statute's requirement that
the Agency determine the specific risk to ``potentially exposed or
susceptible subpopulation[s]''. Although the law defines this term to
include ``infants, children, pregnant women, workers, or the elderly,''
many encouraged the Agency to consider expanding the definition to
include for example: environmental justice communities, Arctic
communities, American Indian communities, communities with little
access to preventative health-care, subsistence fishers, and fence-line
communities. There were a number of stakeholders who encouraged the
Agency to work with the Occupational Safety & Health Administration
(OSHA), the National Institute for Occupational Safety and Health
(NIOSH), and the Consumer Product Safety Commission (CPSC), among other
federal agencies, to better protect against occupational and consumer
exposures. Also regarding exposure, stakeholders encouraged the
examination of cumulative and low dose exposures in risk evaluations,
which are not specifically mentioned in the new statute.
    A number of commenters emphasized the need for EPA to maximize
transparency throughout the evaluation process. The EPA received a
number of comments about the science used to inform individual risk
evaluations, including the types of data, models, policy assumptions
(e.g., default factors) and computational approaches. A number of
commenters argued that a lack of data does not equate to a lack of
risk. Stakeholders encouraged the Agency to engage with industry to
obtain hazard and exposure data and to utilize the new order authority
allowed under the law (TSCA section 4). Commenters suggested an
increased use of EPA's Office of Research and Development (ORD) and
internationally accepted data, models, and products. A number of
stakeholders expressed their support for the new provision in the law
that requires the Agency to reduce and replace vertebrate testing (TSCA
section 4(h)) in obtaining chemical substance hazard and exposure data.
    EPA considered all of these comments in the development of this
proposed rule, and welcomes additional feedback from stakeholders on
the proposed process and requirements presented in this document.

III. The Proposed Rule

A. Policy Objectives

    The risk evaluation process under TSCA is ultimately how EPA will
determine whether a chemical substance presents an unreasonable risk of
injury to health or the environment. The overall objective of this
action is to propose to codify the process by which the Agency
evaluates risk from chemical substances for purposes of TSCA section 6.
In this proposed rule, the Agency details those components of TSCA risk
evaluation and key factors that EPA deems are necessary to consider in
each risk evaluation to ensure that the public has a full understanding
of how risk evaluations will be conducted. However, EPA is not
proposing to establish highly detailed provisions that will address
every eventuality or possible consideration that might arise. Due to
the rapid advancement of the science of risk evaluation and the science
and technology that inform risk evaluation, this proposed rule seeks to
balance the need for the risk evaluation procedures to be transparent,
without unduly restricting the specific science that will be used to
conduct the evaluations, allowing the Agency flexibility to adapt and
keep current with changing science as it conducts TSCA evaluations into
the future.

B. Interagency Collaboration

    EPA recognizes that other Federal agencies may be able to provide
important use, exposure and hazard information that is likely to be
relevant to a risk evaluation of chemical substances. EPA is committed
to interagency engagement and dialogue throughout its risk evaluation
process, including data sharing, information requests, and consultation
regarding specific chemicals of interest. As such,

EPA has reached out to other agencies, inviting them to join the agency
in an open and collaborative dialogue. EPA intends to continue and
expand its interagency collaboration efforts for chemicals management
and risk evaluations under TSCA.
    To coordinate with other agencies on TSCA implementation generally,
EPA intends to continue to use--and expand where appropriate--existing
interagency groups, such as the OMNE (OSHA-MSHA-NIOSH-NIEHS-EPA)
Committee and the National Science and Technology Council (NSTC)'s
Committee on Environment, Natural Resources, and Sustainability's new
Toxicity Assessment Committee. EPA is also committed to interagency
engagement at the working level on individual chemical evaluations.
    To ensure that such collaboration can occur in a timely manner when
needed, EPA intends to initiate interagency consultation through the
existing mechanisms early in the process, and document these measures
in the scope document. However, EPA is concerned that imposing a
single, pre-determined consultation step might lead to an overly
bureaucratic process that could limit or complicate ongoing
collaboration efforts, and so is not proposing to codify any particular
process in this regulation.

C. Scope of Evaluations

    TSCA requires risk evaluations to determine whether or not a
chemical substance presents an unreasonable risk of injury to health or
the environment under the conditions of use, with conditions of use
being defined as ``the circumstances, as determined by the EPA, under
which a chemical substance is intended, known, or reasonably foreseen
to be manufactured, processed, distributed in commerce, used, or
disposed of.'' 15 U.S.C. 2602(4).
    Although some of the commenters during the public meeting suggested
that EPA could evaluate a specific use of a chemical substance, EPA is
not choosing to adopt such an interpretation, for the reasons explained
previously. Also, EPA recognizes that under certain circumstances it
may be necessary to expedite an evaluation for a particular condition
of use to move more rapidly to risk management under TSCA section 6(a)
(15 U.S.C. 2605(a)): this could include a situation in which a single
use presented an unreasonable risk of injury for the population as a
whole or for a susceptible subpopulation (e.g., one use results in
risks that EPA would determine unreasonable regardless of the risk
posed by other uses). However, in any case where EPA would find it
necessary to pursue a risk evaluation in phases, the Agency will still
complete the full risk evaluation on all identified conditions of use
within the statutory 3-year deadline. Therefore, relying on this
discretion, EPA is proposing to explicitly recognize its authority to
complete risk evaluations in phases, and to manage unreasonable risks
as they are identified through those phases under TSCA section 6(a) in
the regulation.

D. Definitions

    TSCA defines a number of key terms necessary for interpretation of
the new law. The definitions within the law apply to this proposed
rule. EPA has also included some additional definitions in the proposed
rule for further clarification; these are noted and defined later in
this document. The law requires EPA to evaluate risk to ``potentially
exposed or susceptible subpopulation[s],'' and although the law
elaborates on this phrase, EPA is proposing to expand the definition
for TSCA purposes. TSCA states that ``the term `potentially exposed or
susceptible subpopulation' means a group of individuals within the
general population identified by the EPA who, due to either greater
susceptibility or greater exposure, may be at greater risk than the
general population of adverse health effects from exposure to a
chemical substance or mixture, such as infants, children, pregnant
women, workers, or the elderly.'' 15 U.S.C. 2602(12). EPA is proposing
to incorporate the phrase ``including but not limited to'' before the
specific subpopulations identified in the statutory definition, to
further clarify that EPA may identify additional subpopulations, where
warranted. As suggested by the statute, EPA is also proposing to
include specific authorization for EPA to consider both intrinsic
(e.g., life stage, reproductive status, age, gender, genetic traits)
and acquired (e.g., pre-existing disease, geography, socioeconomic,
cultural, workplace) factors when identifying this population.
    TSCA section 26(k) (15 U.S.C. 2625(k)) states that in carrying out
risk evaluations, EPA shall consider information that is ``reasonably
available,'' but the statute does not further define this phrase. EPA
is proposing a definition for ``reasonably available'' to mean existing
information that EPA possesses, or can reasonably obtain and synthesize
for use in risk evaluations, considering the deadlines for completing
the evaluation. Generally speaking, EPA does not consider information
that has not yet been generated, as reasonably available, because it
will typically not be feasible for EPA to require significant chemical
testing and receive and assess those test results during the three to
three and a half year window allotted for risk evaluation. Accordingly,
EPA intends to generally ensure that sufficient information to complete
a risk evaluation exists and is available to the Agency prior to
initiating the evaluation (indeed, prior to initiating prioritization).
EPA also generally intends to use its authority under TSCA to require
the development of new information, as necessary, prior to risk
prioritization.
    TSCA requires EPA, as a part of the risk evaluation, to document
whether the Agency has considered aggregate or sentinel exposure, and
the basis for that decision. 15 U.S.C. 2605(b)(4)(F)(ii). These terms
are not defined in the law, so EPA has proposed a definition for
aggregate exposure that is consistent with current Agency policies and
practices. ``Aggregate exposure'' means the combined exposures to an
individual from a single chemical substance across multiple routes and
across multiple pathways (Ref. 20). ``Sentinel'' means the exposure(s)
of greatest significance, which may be the maximum exposure to an
individual, population (or subpopulation), or the environment to the
chemical substance of interest (or any combination thereof). Although
sentinel exposure is not a novel way of characterizing exposure, this
is a new term for EPA.
    Other terms defined in the proposed rule are designed to provide
clarity regarding the science that will be used to conduct an
evaluation. ``Pathways'' of exposure refers to the mode through which
one is exposed to a chemical substance, including but not limited to:
food, water, soil, and air (Ref. 20). ``Routes'' of exposure refer to
the particular manner which a chemical substance may contact the body,
including absorption via ingestion, inhalation, or dermally (Ref. 20).
The statute requires EPA to consider ``the extent to which the
variability and uncertainty . . . are evaluated and characterized.'' 15
U.S.C. 2625(h). EPA is adopting definitions for both ``variability''
and ``uncertainty'' from existing Agency guidance. ``Uncertainty''
means the imperfect knowledge or lack of precise knowledge either for
specific values of interest or in the description of a system (Ref.
21). ``Variability'' means the inherent natural variation, diversity,
and heterogeneity across time and/or space or among individuals within
a population (Ref. 21).

E. Timing of Risk Evaluations

    As indicated, the statute requires EPA to complete risk evaluations
within three years, with the possibility of a six month extension
beyond the three year timeframe. This proposed rule simply adopts these
timeframes without modification or elaboration. EPA acknowledges this
is a relatively short timeframe, and, as discussed elsewhere in this
preamble, is proposing to adopt other procedures that will allow the
Agency to meet these deadlines.

F. Chemical Substances for Risk Evaluation

    As identified previously, chemical substances that will undergo
risk evaluation can be put into three groups: (1) The first ten
chemical substances the Agency is required to identify within the first
180 calendar days of enacting the amendments to TSCA (15 U.S.C.
2605(b)(2)); (2) the chemical substances determined as High-Priority
Substances through the prioritization process proposed in a separate
rulemaking; and (3) requested chemical substances submitted by
manufacturers that meet the criteria for EPA to conduct an Agency risk
evaluation.

G. Process for Manufacturer Requested Risk Evaluations

    TSCA allows a manufacturer or group of manufacturers to submit
requests for Agency conducted risk evaluations for chemical substances
that they manufacture. EPA is proposing the necessary components of the
request in the proposed regulatory text. EPA is proposing to require
that manufacturers demonstrate in their request that there is
sufficient, reasonably available information for the Agency to conduct
a risk evaluation on the chemical substance under the conditions of
use. EPA must complete any manufacturer-requested risk evaluation that
it determines meets the criteria within the statutory three years.
Unlike those chemical substances that have come through the
prioritization process, manufacturer-requested chemical substances have
not undergone initial risk screening and therefore EPA will not assign
such chemicals a high- or low-priority designation. The purpose of the
requirements proposed as the necessary components of the request, is to
allow the Agency to determine whether sufficient information is
``reasonably available'' for EPA to complete a risk evaluation of the
requested chemical under the conditions of use, as that term is defined
under TSCA section 3.
    EPA is proposing to require a manufacturer to submit a list (e.g.,
citations) of the reasonably available information on hazard and
exposure for all the conditions of use. EPA is not requesting
manufacturers submit copies of the cited information. Manufacturers
must include a commitment to provide EPA any referenced data if they
are not publicly available, and must certify that the information
submitted is accurate and complete. EPA will not accept a manufacturer
request where any of the relevant data is not in the possession of the
requestor but is with another entity.
    Consistent with TSCA section 6(b)(4)(E)(iii), EPA will prioritize
requests where there is evidence that restrictions imposed by one or
more States have the potential to have a significant impact on
interstate commerce or health or the environment, and is therefore
proposing to allow (but not require) manufacturers to include any
evidence to support such a finding. Following this required initial
prioritization, EPA is proposing to further prioritize chemical
substances for risk evaluation based on initial estimates of
exposure(s) and/or hazard(s) under one or more conditions of use or any
other factor that EPA determines may be relevant. In general, EPA plans
to prioritize those chemical substances where there is evidence of
relatively high risk over those with less evidence of risk.
    Instructions for submitting CBI are also included in the proposed
rule. EPA believes that TSCA section 14(c)(3) is best read as requiring
upfront substantiation of non-exempt CBI claims. In addition, EPA
believes the obligation to review all non-exempt chemical
identification claims and 25 percent of all other non-exempt claims
will be best effectuated by requiring substantiation at the time of
submission.
    Chemical substances that EPA has prioritized through the
prioritization process (proposed in a separate rulemaking), are subject
to two separate public comment periods prior to the completion of the
prioritization process. EPA expects that these comment periods will
ensure that EPA has the necessary information to evaluate the chemical
substances, including information on all conditions of use.
Consequently, in order to ensure that chemical substances subject to
manufacturer requests undergo risk evaluation only if the available
information is comparable to what EPA will identify or generate through
the measures identified in the proposed prioritization framework rule,
EPA is proposing opportunities to collect additional information from
the public.
    Upon receipt of the request, EPA is proposing to verify that the
request is facially valid, i.e., that information has been submitted
that is consistent with the regulatory requirements. EPA is proposing
that within 30 business days of a receiving a facially valid request,
EPA will submit for publication an announcement of the receipt of the
request in the Federal Register, open a docket for the request, and
provide no less than a 30 calendar day comment period, to allow the
public to identify and/or submit any reasonably available information
regarding hazard, exposure, potentially exposed population(s) and
subpopulation(s), and conditions of use that may help inform a risk
evaluation, including identifying information gaps. The requesting
manufacturer may also submit any additional material during this time.
    Within 9 months after the end of the comment period, EPA will
review the request along with any additional information received
during the comment period to determine whether the request meets the
regulatory criteria and will notify the manufacturer(s) accordingly.
This time will allow EPA to develop the equivalent of a conceptual
model to describe actual or predicted relationships between the
chemical substance and the receptors, either human or environmental,
with consideration of potential hazards throughout the life cycle of
the chemical substance--from manufacturing, processing, distribution in
commerce, storage, use, or disposal. If EPA determines that the request
is compliant (i.e., it has the required information necessary for
conducting a risk evaluation), EPA will begin the risk evaluation
process consistent with TSCA section 6(b)(4)(E)(i). If the request is
found insufficient EPA will identify the information that would be
necessary to conduct the risk evaluation in its notification to the
manufacturer. The manufacturer will have 60 calendar days from receipt
of EPA's determination to submit the additional information. EPA will
consider the request withdrawn if the manufacturer(s) fails to submit
the additional information identified. The process for conducting the
risk evaluation will otherwise be identical to the process for those
chemical substance identified as a High-Priority Substance through the
Prioritization Process, which is addressed in a separate proposed rule.

H. Risk Evaluation General Provisions

    1. Agency guidance. EPA has a number of existing guidance documents
that inform Agency risk assessment.

EPA has been using risk assessments to characterize the nature and
magnitude of health risks to humans and ecological receptors from
chemical contaminants and other stressors that may be present in the
environment since its inception. Over the years, EPA has worked with
the scientific community and other stakeholders to develop a variety of
guidance, guidelines, methods and models for use in conducting
different kinds of assessments. A compendium of existing Agency
guidance related to risk assessments is maintained at https://www.epa.gov/risk/risk-assessment-guidelines. A compendium of guidance,
databases and models used for assessing pesticide risks is available at
https://www.epa.gov/pesticide-science-and-assessing-pesticide-risks,
and information about available predictive models and tools for
assessing chemicals under TSCA can be found at https://www.epa.gov/tsca-screening-tools. Each of these Web sites identify and link to a
number of written guidance documents, tools and models. Rather than
starting anew, EPA intends to take advantage of existing guidance,
tools and models that are relevant and available for use in conducting
a risk evaluation under this program.
    Since the law requires the development of additional ``policies,
procedures, and guidance the Administrator determines are necessary''
to carry out the process in TSCA (15 U.S.C. 2625(l)). EPA may also
develop additional guidance(s) for risk evaluation in the future.
    2. Categories of chemical substances. TSCA provides EPA with
authority to take action on categories of chemical substances: groups
of chemical substances which are, for example, similar in molecular
structure, in physical, chemical, or biological properties, in use, or
in mode of entrance into the human body or into the environment.
Although the proposed rule most often references ``chemical
substances,'' EPA is also proposing to include a clear statement in the
regulation that nothing in the proposed rule shall be construed as a
limitation on EPA's authority to take action with respect to categories
of chemical substances, and that, where appropriate, EPA can prioritize
and evaluate categories of chemical substances.
    3. Information and information sources. As discussed, the timeframe
for completing risk evaluation is compressed. For those chemical
substances chosen by EPA to undergo the risk evaluation process, EPA
expects to only initiate the process when EPA has determined that most
of the information necessary to complete the evaluation is reasonably
available, which in most cases means the information already exists. As
appropriate, however, EPA will exercise its TSCA information
collection, testing, and subpoena authorities, including those under
TSCA sections 4, 8, and 11(c) to develop the information needed for a
risk evaluation. Pursuant to TSCA section 8(e), the law requires that
any person who manufacturers, processes, or distributes in commerce a
chemical substance or mixture and who obtains information which
supports the conclusion that this substance presents a substantial risk
of injury to health or the environment, shall immediately inform the
Agency.
    To conduct a risk evaluation, EPA will rely on a combination of
information, models, screening methods, and accepted science policies,
which include defaults, reasonable estimates, and uncertainty factors,
in addition to considering information generated from evolving science
and technology. EPA expects to obtain scientific advice from the
Science Advisory Committee on Chemicals, which the Agency is required
to develop and convene under TSCA section 26(o). In compliance with the
statute, EPA will work to reduce and replace, to the extent
practicable, the use of vertebrate animals in testing chemical
substances as outlined in TSCA section 4(h).

I. Risk Evaluation Steps

    1. Scope. The first step of a risk evaluation is the development of
the scope. In compliance with the statute, the scope will identify the
conditions of use, hazards, exposures, and any potentially exposed or
susceptible subpopulations that the EPA expects to consider. EPA is
also proposing to include additional information in the scoping
document, including any models, screening methods, and any accepted
science policies expected to be used during the risk evaluation. EPA is
further proposing to include a conceptual model that will describe the
actual or predicted relationships between the chemical substance and
the receptors, either human or environmental, with consideration of
potential hazards throughout the life cycle of the chemical substance--
from manufacturing, processing, distribution in commerce, storage, use,
to release or disposal. Also included will be an analysis plan, which
will identify the approaches and methods EPA plans to use to assess
exposure, effects, and risk, including associated uncertainty and
variability, as well as a strategy for approaching science policy
decisions (e.g., defaults or uncertainty factors).
    The announced availability of the final scope will be published in
the Federal Register within six months of the initiation of the risk
evaluation. Although not required under the statute, EPA has proposed
to provide a draft scope for a 45 calendar day public comment period
during this six month period. EPA welcomes all public participation,
but specifically encourages commenters to provide information they
believe might be missing or may further inform the risk evaluation.
That said, EPA expects to use the comment periods during the
prioritization process to reduce the likelihood of significant comments
on the draft scope. Consequently, the proposed rule makes clear that
all comments that could be raised on information and approaches
presented in the scope must be presented during this comment period.
Any issues related to scope not raised in comments at this time cannot
form the basis for an objection or challenge in a future administrative
or judicial proceeding. This is a well-established principle of
administrative law and practice, see, e.g., Nuclear Energy Institute v.
EPA, 373 F.3d 1251, 1290-1291 (D.C. Cir. 2004), and the need for such a
provision is reinforced by the statutory deadlines under which EPA must
operate for completing TSCA risk evaluations. Note that EPA is not
proposing to preclude parties from raising newly discovered
information, or from raising issues that could not have been fairly
raised during this comment period. Rather, EPA seeks merely to prevent
parties from delaying the risk evaluation by withholding information or
by providing it piecemeal.
    2. Hazard assessment. In compliance with TSCA section 6(b)(4)(F),
EPA is proposing that a hazard assessment be conducted on each chemical
substance or category. A hazard assessment identifies the types of
adverse health or environmental effects that can be caused by exposure
to some agent in question, and to characterize the quality and weight
of evidence supporting this identification. Hazard Identification is
the process of determining whether exposure to a stressor can cause an
increase in the incidence of specific adverse health or environmental
effects (e.g., cancer, developmental toxicity).
    This hazard assessment may include, but may not be limited to,
evaluation of the potential toxicity of the chemical substance with
respect to cancer, mutation, reproductive, developmental, respiratory,
immune, metabolic, and cardiovascular impacts, and

neurological impairments. The assessment will evaluate effects at life
stage(s) most appropriate for a receptor target. The hazard assessment
will consider the dose or concentration and resulting effect or
response. Potential information sources that may support the health
assessment include but are not limited to: Human epidemiological
studies; in vivo and/or in vitro laboratory studies; mechanistic or
kinetic studies in a variety of test systems, including but not limited
to toxicokinetics and toxicodynamics, computational toxicology; data
from structure-activity relationships, high-throughput assays, genomic
response assays, and ecological field data. Specifically, for human
health hazards, the assessment will consider all potentially exposed or
susceptible subpopulation(s) identified in the scope and use
appropriate combination, if available, of population-based
epidemiological studies, information related to geographic location of
susceptible subpopulations, models representing health effects to the
population, and any other relevant, scientifically valid information or
methodology. In an environmental hazard assessment, the relationship
between the chemical substance and the occurrence of an ecological
response will be evaluated using field or laboratory data, modeling
strategies, and species extrapolations.
    Where possible, a hazard assessment also will include a dose-
response assessment. A dose-response relationship describes how the
likelihood and severity of adverse health effects (the responses) are
related to the amount and condition of exposure to an agent (the dose
provided). The same principles generally apply for studies where the
exposure is to a concentration of the agent (e.g., airborne
concentrations applied in inhalation exposure studies or water or other
media concentrations for ecological exposure studies), and the
resulting information is referred to as the concentration-response.
    3. Exposure assessment. Pursuant to TSCA section 6(b)(4)(F), EPA,
where relevant, will take into account the likely duration, intensity,
frequency, and number of exposures under the conditions of use in an
exposure assessment. An exposure assessment includes some discussion of
the size, nature, and types of individuals or populations exposed to
the agent, as well as discussion of the uncertainties in this
information. Exposure can be measured directly, but more commonly is
estimated indirectly through consideration of measured concentrations
in the environment, consideration of models of chemical transport and
fate in the environment, and estimates of human intake or environmental
exposure over time.
    Using reasonably available information, exposures will be estimated
(usually quantitatively) for the identified conditions of use. For
human health exposure, the assessment would consider all potentially
exposed or susceptible subpopulation(s) identified in the scope and
utilize any combination, as available, of population-based
epidemiological studies, information related to geographic location of
susceptible subpopulations, models representing exposures to the
population, measurements in human tissues or relevant environmental or
exposure media, and any other relevant, scientifically valid
information or methodology. In an environmental health exposure
assessment, the interaction of the chemical substance with any
ecological characteristics identified in the scope will be
characterized and evaluated.
    4. Risk characterization. TSCA requires that a risk evaluation
``integrate and assess available information on hazards and
exposures''. (15 U.S.C 2605(b)(4)(F). A risk characterization conveys
the risk assessor's judgment as to the nature and presence or absence
of risks, along with information about how the risk was assessed, where
assumptions and uncertainties still exist, and where policy choices
will need to be made. Risk characterization takes place for both human
health risk assessments and ecological risk assessments.
    In practice, each component of the risk assessment (e.g. hazard
assessment, dose-response assessment, exposure assessment) has an
individual characterization written to carry forward the key findings,
assumptions, limitations, and uncertainties. The set of these
individual characterizations provide the information basis to write an
integrative risk characterization analysis. The final, overall risk
characterization thus consists of the individual component
characterizations plus an integrative analysis.
    Each risk evaluation will quantitatively and/or qualitatively
estimate and characterize risk for the identified populations and
ecological characteristics under the conditions of use. The risk
characterization will also describe whether aggregate or sentinel
exposures were considered and provide the evidence and information to
support the consideration.
    In the risk characterization, EPA will further carry out the
obligations under TSCA section 26(h) (15 U.S.C 2625(h)); for example,
by assessing uncertainty and variability in each step of the risk
evaluation, discussing considerations of data quality such as the
reliability, relevance and whether the methods utilized were reasonable
and consistent, explaining any assumptions used, and discussing
information generated from independent peer review. EPA also may
exercise it discretion to include a discussion of any alternative
interpretation of results generated from the risk evaluation. For
environmental evaluations specifically, EPA plans to include a
discussion of the nature and magnitude of the effects, the spatial and
temporal patterns of the effects, implications at the individual,
species, and community level, and the likelihood of recovery subsequent
to exposure to the chemical substance.
    5. Peer review. For each risk evaluations conducted on chemicals
identified pursuant to TSCA section 6(b)(4)(A), EPA will conduct peer
reviews using the guidance provided in executive branch peer review
directives included in the Office of Management and Budget Final
Information Quality Bulletin for Peer Review (OMB Bulletin) (Ref. 22)
and the guidance set forth in the EPA Peer Review Handbook (2015) (Ref.
23) or its updates.
    The goal of the peer review process is to obtain independent review
from experts who have not contributed to its development. According to
EPA's peer review policy, peer review of all scientific and technical
information that is intended to inform or support Agency decisions is
encouraged and expected. Both the EPA Peer Review Handbook and the OMB
Bulletin provide standards for when and how to conduct peer review on
science documents. The documents do not contemplate that peer review is
necessary for every document or risk assessment, but is expected to
occur for those documents that have either:
     Influential scientific information: scientific information
that the Agency reasonably can determine will have or does have a clear
and substantial impact on important public policies or private sector
decisions, or
     Highly influential scientific assessment: a subset of
influential scientific information that could have a potential impact
of more than $500 million in any year on either the public or private
sector or is novel, controversial, or precedent-setting, or has
significant interagency interest.
    The EPA Peer Review Handbook, first released in 1998 and last
updated in

2015, has also been instrumental in providing guidance on the methods
for conducting peer review at the Agency for the past two decades.
According to the Handbook the peer review approach can consist of
internal or external reviewers and can range from a letter review, an
ad hoc expert panel review, review of a journal manuscript by a
referred scientific journal, review by an established Federal Advisory
Committee (FAC), review by an Agency-appointed special board or
commission, or review by the National Academy of Science. Given that
this guidance reflects long-standing and well-accepted EPA practices on
peer review, and given the public's familiarity with it, the Agency is
proposing to continue to rely on that established guidance, rather than
attempt to modify it or create some new methodology in this rulemaking.
As discussed earlier in this proposal, EPA will identify aspects of the
analysis on which peer review will be conducted, and the planned
methodologies, as part of the draft scoping document that will undergo
public comment for each chemical substance that undergoes risk
evaluation. These may include novel models or analyses that warrant an
in-depth peer review. In addition to any targeted peer review of
specific aspects of the analysis, the entire risk assessment will also
undergo peer review, as it is important for peer reviewers to consider
how the various underlying analyses fit together to produce an
integrated risk characterization which will form the basis of an
unreasonable risk determination.
    The peer review will address aspects of the science underlying the
assessment, including, but not limited to hazard assessment, assessment
of dose-response, exposure assessment, and risk characterization.
Please note, however, EPA will not seek review of any determination as
to whether the risks are ``unreasonable'', which is an Agency policy
judgement. The purpose of peer review is for independent review of the
science underlying the risk assessment, not to evaluate EPA's policy
judgments. TSCA expressly reserves to the Agency the final
determination of whether risk posed by a chemical substance is
``unreasonable.'' 15 U.S.C 2605(i). EPA nevertheless will include its
unreasonable risk judgment as part of the risk evaluation that is
subject to public review and comment.
    6. Unreasonable risk determination. The final step of a risk
evaluation is for the EPA to determine whether the chemical substance
presents an unreasonable risk of injury to health or the environment.
The EPA may find that the substance does not present an unreasonable
risk of injury to health or the environment under the conditions of
use. This will be issued by order, published in the Federal Register,
and considered to be a final EPA action. Alternatively, the EPA may
determine that the substance does present an unreasonable risk under
one or more conditions of use, in which case EPA must, pursuant to TSCA
section 6(a) (15 U.S.C. 2605(a)), impose requirements to the extent
necessary so that the substance no longer presents such risk.
    EPA will announce in the Federal Register the availability of and
solicit public comment on the draft risk evaluation, including the
unreasonable risk determination. All comments that could be raised on
components of the draft risk evaluation must be presented during this
comment period. Any issues not raised during this time will be
considered to have been waived, and may not form the basis for an
objection or challenge in any subsequent administrative or judicial
proceeding.
    7. Additional publically available information. Pursuant to TSCA
section 26(j), EPA will make available: (1) All notices,
determinations, findings, consent agreements, and orders; (2) any
information required to be provided by the EPA under 15 U.S.C. 2603;
(3) a nontechnical summary of the risk evaluation; (4) a list of the
studies with the results of the studies, considered in carrying out
each risk evaluation; and (5) the final peer review report, including
the response to peer review comments.
    8. Reassessment of unreasonable risk determination. EPA may
reassess a final unreasonable risk determination of a chemical
substance at any time based on information available to the Agency.

IV. Request for Comments

    While EPA is seeking public comment on all aspects of this proposed
rule, there are areas where the Agency specifically requesting public
input.
    1. Redefining scientific terms. EPA received a number of
stakeholder comments regarding EPA's approach to defining a number of
important terms within this rule. These terms include ``best available
science'', ``weight-of-the-evidence'', ``sufficiency of information'',
``unreasonable risk'', and ``reasonably available information'' among
others. Many of the terms used in the proposed rule are not novel
concepts and are already in use and the meaning of which is discussed
extensively in existing Agency guidance. For example, extensive
descriptions for the phrases ``best available science'', ``weight-of-
the-evidence'', and ``sufficiency of information'' can be found in
EPA's Risk Characterization Handbook (Ref. 24), and in other existing
Agency guidance.
    EPA believes further defining these and other terms in the proposed
rule is unnecessary and ultimately problematic. These terms have and
will continue to evolve with changing scientific methods and
innovation. Codifying specific definitions for these phrases in this
rule may inhibit the flexibility of the Agency to quickly adapt and
implement changing science. The Agency intends to use existing guidance
definitions and will update definitions and guidance as necessary.
    However, the Agency welcomes public comments regarding the pros and
cons of codifying these or other definitions and/or approaches for
these or any other terms. EPA encourages commenters to suggest
alternative definitions the Agency should consider for codification in
this procedural rule. Please explain your views as clearly as possible,
providing specific examples to illustrate your concerns and suggest
alternate wording, where applicable. EPA is specifically requesting
comments on whether EPA should define unreasonable risk in the final
rule. If so, acknowledging that the statute precludes consideration of
costs and other non-risk factors at this step, what factors should EPA
consider in making such a determination.
    2. Margin of exposure. EPA currently uses a margin-of-exposure
(MOE) approach in risk characterization of TSCA risk assessments.
Please comment on the strengths and weaknesses of the MOE approach. Are
there other approaches (e.g. use of hazard indices, use of
probabilistic risk assessment) that might better suit the TSCA Risk
Evaluation Program? Are there other approaches that provide
quantifiable non-cancer risks?
    3. Systematic Review. While EPA has included a systematic review
approach in the past, and intends to continue to do so, please comment
on the need for regulatory text prescribing a specific systematic
review approach for hazard identification, including the
appropriateness of elements that might be included or concerns about
codifying an approach.
    4. Manufacturer Requests. EPA anticipates that some chemical
substances prioritized for risk evaluation have been manufactured by
persons who possess unpublished information that could impact the
chemical's risk determination. For chemical substances prioritized for
risk evaluation, the Agency generally expects to exercise, as needed,
among

other authorities, its information-gathering authority pursuant to 15
U.S.C. 2607(a) and 2607(d), likely very early in the process. EPA is
specifically requesting comment on approaches to utilizing its
information gathering authorities to assure that EPA has the most
complete information to make its risk determination. For example, one
option might be to incorporate its 15 U.S.C. 2607(a) and 2607(d)
authority into the ``Information and information sources'' section of
this rule to allow EPA to require, by notice in the Federal Register,
manufacturers with information subject to 15 U.S.C. 2607(a)(2) and
2607(d) to submit that information to EPA for use in a risk evaluation.
EPA is requesting comment on this option and on any more effective
alternative methods to exercise this authority within the rule to
assure the completeness of the information relevant to the risk
evaluation.
    The Agency also anticipates the possibility that one manufacturer
requests a risk evaluation but other manufacturers of the same chemical
who have not joined in the request also possess relevant unpublished
information. For manufacturer requests for risk evaluation, the burden
is on the requester to include or reference all information that is
necessary for EPA to conduct a risk evaluation. Although EPA could use
its data collection authority to access information, including
unpublished studies, held by entities other than the requestor, the
Agency intends to deny requests for risk evaluation if the requester
does not have access to the information necessary for risk evaluation.
    5. Peer Review. As discussed in both the OMB Bulletin and the EPA
Peer Review Handbook, there are specific exemption criteria for
information that does not necessitate peer review, even if it might be
considered to be influential or highly influential. A number of
specific circumstances where peer review is not necessary are discussed
in section 3.3 of the EPA Peer Review Handbook. Examples of these
circumstances include information involving a health or safety issue
where the Agency determines that the dissemination is time-sensitive or
if an application of an adequately peer-reviewed work product does not
depart significantly from its scientific or technical approach. In
addition, EPA expects that there will be individual circumstances where
a chemical substance is found to not present an unreasonable risk or
that findings are similar or the same as other jurisdictions (states or
countries) that have reached similar conclusions based on the same
information, such that the Agency could determine that peer review is
not necessary for that chemical risk evaluation.
    EPA expects that many of the risk evaluations conducted under TSCA
will necessitate peer review. In cases in which a chemical substance is
determined to present an unreasonable risk, the Agency must promptly
move to manage the risk, a circumstance that would typically qualify
the assessment as ``influential scientific information'' under current
guidance and practice. The Agency also expects that some risk
evaluations would also be highly influential scientific assessments,
e.g., contain novel, controversial, or precedent-setting science with
significant interagency interest. EPA also expects that peer review
will be warranted in many cases where the Agency determines a chemical
substance does not present an unreasonable risk. Aspects of the
evaluation may qualify as influential scientific information or highly
influential scientific assessment, and thus warrant peer review. Other
circumstances where the Agency may determine that peer review is
warranted could include circumstances where there are existing private
sector standards suggesting concern for a given chemical substance,
where existing state assessments differ from the EPA evaluation, or
where the public has expressed general concern about the chemical
substances effects.
    As required under the amended TSCA, chemical substances must be
prioritized as either low or high. Those categorized as high are
subject to a risk evaluation, and those determined to be low are not.
The bar for prioritizing a chemical as a low priority as required under
the amended TSCA is fairly high. As such, EPA expects that, as an
increasing number of chemical risk evaluations are completed, those
chemical substances that present risk to human health or the
environment will be managed accordingly, leaving an increasing number
of chemicals that do not present an unreasonable risk. The Agency
questions whether all future risk evaluations warrant peer review.
    EPA is specifically requesting public comment on whether there are
circumstances where conducting peer review may not be warranted. What
circumstances might qualify, and whether the regulatory text should be
adjusted to require EPA to make a case by case determination of whether
and to what extent, consistent with the EPA Peer Review Handbook, peer
review is warranted for the chemical substance undergoing a risk
evaluation. In all cases, the rule would require that this
determination, and any peer review activities that are conducted, be
documented for each chemical evaluation, starting with the scope
document.
    6. Reliance on existing guidance and procedures for conducting risk
evaluations. As discussed in Unit III.G.1., EPA intends to take
advantage of existing guidance, tools and models that are relevant and
available for use in conducting a risk evaluation under this program.
Since each risk evaluation is based on the specific circumstances
surrounding the chemical being assessed, EPA has not attempted to
codify any specific guidance, method or model. EPA believes that this
is necessary to ensure that there is flexibility to address potentially
unique circumstances on a chemical basis. EPA is interested in your
comments about this approach, and where there is any existing guidance
that may be of particular interest for consideration in conducting
these risk evaluations. Additionally, EPA asks if the current guidance
documents are sufficient and whether there are additional guidance
documents that should be relevant but may not be on the lists available
on EPA's Web site (https://www.epa.gov/risk/risk-assessment-guidelines). Finally, should EPA consider requiring that a list of
appropriate guidance documents be included on a case-by-case basis as
part of the scoping document that undergoes public review and comment.
    7. Interagency collaboration. As discussed in Unit III.B., EPA is
committed to ensuring there is interagency engagement and dialogue
throughout its risk evaluation process, and has chosen not the limit
the potential interagency collaboration by proposing to codify any
particular process. EPA is concerned that imposing a single, pre-
determined consultation step might lead to an overly bureaucratic
process that could limit or complicate ongoing collaboration efforts,
and so is not proposing to codify any particular process in this
regulation. However, EPA is requesting specific public comment on
whether codifying this collaboration at a specific point in the
regulation is necessary.

V. References

    The following is a listing of the documents that are specifically
referenced in this document. The docket includes these documents and
other information considered by EPA, including documents that are
referenced within the documents that are included

in the docket, even if the referenced document is not physically
located in the docket. For assistance in locating these other
documents, please consult the technical person listed under FOR FURTHER
INFORMATION CONTACT.

1. USEPA. Information Collection Request (ICR) for the Proposed
Rule: Procedures for Chemical Risk Evaluation Under TSCA. EPA ICR
No.: 2559.01 and OMB No. 2070--[NEW].
2. EPA. TSCA Work Plan Chemical Assessments: 2014 Update-Final.
Office of Pollution Prevention and Toxics. October 2014. https://www.epa.gov/sites/production/files/2015-01/documents/tsca_work_plan_chemicals_2014_update-final.pdf.
3. National Research Council. Science and Decisions: Advancing Risk
Assessment. The National Academies Press. Washington, DC 2009.
http://www.nap.edu/catalog.php?record_id=12209.
4. EPA. Guidelines for Carcinogen Risk Assessment. Risk Assessment
Forum, Washington, DC. EPA/630/P-03/001F. Washington, DC 2005.
https://www.epa.gov/sites/production/files/2013-09/documents/cancer_guidelines_final_3-25-05.pdf.
5. EPA. Guidelines for Carcinogen Risk Assessment, Review Draft,
CEA-F-0644, Office of Research and Development. Washington, DC 1999.
http://cfpub.epa.gov/ncea/raf/cancer.cfm.
6. EDSTAC. Endocrine Disruptor Screening and Testing Advisory
Committee, Final Report, Volume I-II. Washington, DC 1998. http://www.epa.gov/scipoly/oscpendo/pubs/edspoverview/finalrpt.htm.
7. EPA. Endocrine Disruptor Screening Program; Weight-of-Evidence:
Evaluating Results of EDSP Tier 1 Screening to Identify the Need for
Tier 2 Testing, Washington, DC 2011. https://www.regulations.gov/document?D=EPA-HQ-OPPT-2010-0877-0021.
8. EPA. Framework for Metals Risk Assessment of the Office of the
Science Advisor, Risk Assessment Forum. Washington, DC March 2007.
9. National Research Council. Risk Assessment in the Federal
Government: Managing the Process. The National Academies Press.
Washington, DC 1983. http://www.nap.edu/openbook.php?isbn=0309033497.
10. National Research Council. Science and Judgment in Risk
Assessment. The National Academies Press. Washington, DC 1994.
http://www.nap.edu/catalog.php?record_id=2125.
11. National Research Council. Understanding Risk: Informing
Decisions in a Democratic Society. The National Academies Press.
Washington, DC 1996. http://www.nap.edu/openbook.php?isbn=030905396X.
12. National Research Council. Toxicity Testing in the 21st Century:
A Vision and a Strategy. The National Academies Press. Washington,
DC 2007. http://www.nap.edu/catalog.php?record_id=11970.
13. National Research Council. Phthalates and Cumulative Risk
Assessment: The Tasks Ahead. National Academy Press. Washington, DC
2008. http://www.nap.edu/catalog.php?record_id=12528.
14. USEPA. Policy on Evaluating Health Risks to Children. 1995.
https://www.epa.gov/sites/production/files/2014-05/documents/1995_childrens_health_policy_statement.pdf.
15. USEPA. Guidelines for Developmental Toxicity Risk Assessment.
EPA/600/FR-91/001. Risk Assessment Forum. Washington, DC 1991.
http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=23162.
16. USEPA. Guide to Considering Children's Health When Developing
EPA Actions: Implementing Executive Order 13045 and EPA's Policy on
Evaluating Health Risks to Children. Office of Policy, Economics and
Innovation. Washington, DC 2006. http://yosemite.epa.gov/ochp/
ochpweb.nsf/content/ADPguide.htm/$File/EPA_ADP_Guide_508.pdf.
17. USEPA. Guidance on Selecting Age Groups for Monitoring and
Assessing Childhood Exposures to Environmental Contaminants. Final.
EPA/630/P-03/003F. Risk Assessment Forum. Washington, DC 2005.
http://www.epa.gov/raf/publications/guidance-on-selecting-age-groups.htm.
18. USEPA. Supplemental Guidance for Assessing Susceptibility from
Early-Life Exposure to Carcinogens. EPA/630/R-03/003F. Risk
Assessment Forum. Washington, DC 2005. http://www.epa.gov/ttn/atw/childrens_supplement_final.pdf.
19. USEPA. A Framework for Assessing Health Risk of Environmental
Exposures to Children. Final. EPA/600/R-05/093F. Office of Research
and Development, National Center for Environmental Assessment.
Washington, DC 2006. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=158363.
20. USEPA. Exposure Factors Handbook. EPA/600/R-090/052F. Office of
Research and Development, National Center for Environmental
Assessment. Washington, DC 2011. https://cfpub.epa.gov/ncea/risk/recordisplay.cfm?deid=236252.
21. USEPA. Framework for Human Health Risk Assessment to Inform
Decision Making. EPA/100/R-14/001. Office of the Science Advisor,
Risk Assessment Forum. 2014. https://archive.epa.gov/raf/web/pdf/hhra-framework-final-2014.pdf.
22. Office of Management and Budget Final Information Quality
Bulletin for Peer Review.
23. USEPA. Peer Review Handbook. 3rd ed. EPA/100/B-06/002. Science
Policy Council. Washington, DC 2006. https://www.epa.gov/osa/peer-review-handbook-4th-edition-2015.
24. Risk Characterization Handbook. Science Policy Council Handbook:
Risk Characterization, EPA 100-B-00-002, Washington, DC December
2000. https://www.epa.gov/risk/risk-characterization-handbook.

VI. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders
can be found at http://www2.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review

    This action is a significant regulatory action that was submitted
to the Office of Management and Budget (OMB) for review under Executive
Orders 12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821,
January 21, 2011). Any changes made in response to OMB recommendations
have been documented in the docket.

B. Paperwork Reduction Act (PRA)

    The information collection activities associated with this proposed
rule have been submitted to OMB for review and approval under the PRA,
44 U.S.C. 3501 et seq. Specifically, EPA has prepared an ICR to
estimate the potential burden and costs associated with the proposed
requirements for submitting a request for an Agency-conducted risk
evaluation on a particular chemical substance. The ICR, which is
available in the docket, has been assigned the EPA ICR number 2559.01.
You can find a copy of the ICR in the docket for this proposed rule
(Ref. 1), and it is briefly summarized here.
    Respondents/affected entities: Manufacturers (including importers).
    Respondent's obligation to respond: Optional, i.e., needed only if
they are requesting an EPA-conducted risk evaluation for a particular
chemical substance.
    Estimated number of respondents: 10.
    Frequency of response: On occasion.
    Total estimated annual burden: 960.3 hours. Burden is defined in 5
CFR 1320.3(b).
    Total estimated annual cost: $69,353 for burden hours. There are no
M&O costs.
    An agency may not conduct or sponsor, and a person is not required
to respond to a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for the
EPA's regulations in 40 CFR are listed in 40 CFR part 9.
    Submit your comments on the Agency's need for this information, the
accuracy of the provided burden estimates, and any suggested methods
for minimizing respondent burden to EPA using the docket identified at
the beginning of this proposed rule. You may also send your ICR-related
comments to OMB's Office of

Information and Regulatory Affairs via email to
<EMAIL_ADDRESS>Attention: Desk Officer for the EPA. Since
OMB is required to make a decision concerning the ICR between 30 and 60
calendar days after receipt, OMB must receive comments no later than
February 21, 2017. Any ICR-related comments will be addressed with the
final rule.

C. Regulatory Flexibility Act (RFA)

    EPA certifies under section 605(b) of the RFA, 5 U.S.C. 601 et
seq., that this action will not have a significant economic impact on a
substantial number of small entities. Although this proposed rule
primarily addresses internal EPA procedures and activities associated
with conducting risk evaluations for chemical substances as required by
TSCA, EPA is also proposing the process and content requirements for a
manufacturer (including importer) to request that EPA conduct a risk
evaluation on a particular chemical substance. EPA has determined that
the process and content requirements proposed will have minimal impact
on an entity, regardless of size, because there is no mandate for them
to make such a request, and the information they must provide should
they decide to make such a request, which involves basic information
about the chemical substance and the manufacturer's reasons for
requesting the EPA-conducted risk evaluation on that chemical
substance, should be readily available to the manufacturer. Estimated
potential burden and costs are presented in the ICR (Ref. 1).

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. The action imposes no enforceable duty on any state,
local or tribal governments or the private sector.

E. Executive Order 13132: Federalism

    This action does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999). It will not have
substantial direct effects on the states, on the relationship between
the national government and the states, or on the distribution of power
and responsibilities among the various levels of government.

F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments

    This action does not have tribal implications as specified in
Executive Order 13175 (65 FR 67249, November 9, 2000). It will not have
substantial direct effects on one or more Indian tribes, on the
relationship between the Federal Government and Indian tribes, or on
the distribution of power and responsibilities between the Federal
Government and Indian tribes. Thus, Executive Order 13175 does not
apply to this action.

G. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks

    The EPA interprets Executive Order 13045 (62 FR 19885, April 23,
1997) as applying only to those regulatory actions that concern
environmental health or safety risks that the EPA has reason to believe
may disproportionately affect children, per the definition of ``covered
regulatory action'' in section 2-202 of the Executive Order. This
action is not subject to Executive Order 13045 because it does not
concern an environmental health risk or safety risk.

H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use

    This action is not a ``significant energy action'' as defined in
Executive Order 13211 (66 FR 28355, May 22, 2001), because it is not
likely to have a significant adverse effect on the supply, distribution
or use of energy.

I. National Technology Transfer and Advancement Act (NTTAA)

    This action does not involve any technical standards, and is
therefore not subject to considerations under NTTAA section 12(d), 15
U.S.C. 272 note.

J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations

    This action does not establish an environmental health or safety
standard, and is therefore not is not subject to environmental justice
considerations under Executive Order 12898 (59 FR 7629, February 16,
1994). This is procedural rule that will not affect the level of
protection provided to human health or the environment.

List of Subjects in 40 CFR Part 702

    Environmental protection, Chemicals, Chemical Substance, Hazardous
substances, Health and safety, Risk Evaluation.

    Dated: January 12, 2017,
Gina McCarthy,
Administrator.

    Therefore, it is proposed that 40 CFR chapter I, subchapter R, be
amended as follows:

PART 702--GENERAL PRACTICES AND PROCEDURES

0
 1. The authority citation for part 702 is revised to read as follows:

     Authority:  15 U.S.C. 2605 and 2619.

0
 2. Add subpart B to part 702 to read as follows:

Subpart B--Procedures for Chemical Substance Risk Evaluations

Sec.
702.31 General provisions.
702.33 Definitions.
702.35 Chemical substances designated for risk evaluation.
702.37 Submission of manufacturer requests for risk evaluations.
702.39 Evaluation requirements.
702.41 Risk characterization and peer review procedures.
702.43 Unreasonable risk determination.
702.45 Risk Evaluation timeframes and actions.
702.47 Publically available information.

Sec.  702.31   General provisions.

    (a) Purpose. This subpart establishes the EPA process for
conducting a risk evaluation to determine whether a chemical substance
presents an unreasonable risk of injury to health or the environment as
required under TSCA section 6(b)(4)(B) (15 U.S.C. 2605(b)(4)(B)).
    (b) Scope. These regulations establish the general procedures, key
definitions, and timelines EPA will use in a risk evaluation conducted
pursuant to TSCA section 6(b) (15 U.S.C. 2605(b)).
    (c) Applicability. The requirements of this part apply to all
chemical substance risk evaluations initiated pursuant to TSCA section
6(b) (15 U.S.C. 2605(b)).
    (d) Enforcement. Submission to EPA of inaccurate, incomplete, or
misleading information by a manufacturer pursuant to a risk evaluation
conducted pursuant to 15 U.S.C. 2605(b)(4)(B) is a prohibited act under
15 U.S.C. 2614, subject to penalties under 15 U.S.C. 2615 and Title 18
of the U.S. Code.

Sec.  702.33   Definitions.

    All definitions in TSCA apply to this subpart. In addition the
following definitions apply:
    Act means the Toxic Substances Control Act, as amended (15 U.S.C.
2601 et seq.).
    Aggregate exposure means the combined exposures to an individual

from a single chemical substance across multiple routes and across
multiple pathways.
    EPA means the U.S. Environmental Protection Agency.
    Pathways means the mode through which one is exposed to a chemical
substance, including but not limited to: Food, water, soil, and air.
    Potentially exposed or susceptible subpopulation means a group of
individuals within the general population identified by the Agency who,
due to either greater susceptibility or greater exposure, may be at
greater risk than the general population of adverse health effects from
exposure to a chemical substance or mixture, including but not limited
to, infants, children, pregnant women, workers, or the elderly. EPA may
identify a susceptible subpopulation in an individual risk evaluation
upon consideration of various intrinsic (e.g., life stage, reproductive
status, age, gender, genetic traits) or acquired (e.g., pre-existing
disease, geography, workplace) characteristics that may affect exposure
or modify the risk of illness or disease.
    Reasonably available information means existing information that
EPA possesses or can reasonably obtain and synthesize for use in risk
evaluations, considering the deadlines specified in TSCA section
6(b)(4)(G) for completing such evaluation.
    Routes means the particular manner which a chemical substance may
contact the body, including absorption via ingestion, inhalation, or
dermally (integument).
    Sentinel exposure means the exposure(s) of greatest significance,
which may be the plausible maximum exposure to an individual,
population (or subpopulation), or the environment to the chemical
substance of interest (or any combination thereof).
    Uncertainty means the imperfect knowledge or lack of precise
knowledge either for specific values of interest or in the description
of a system.
    Variability means the inherent natural variation, diversity, and
heterogeneity across time and/or space or among individuals within a
population.

Sec.  702.35   Chemical substances designated for risk evaluation.

    (a) Chemical Substances Undergoing Risk Evaluation. A risk
evaluation for a chemical substance designated by the Agency as a High-
Priority Substance pursuant to the prioritization process described in
subpart A, identified under 15 U.S.C. 2605(b)(2)(A), or initiated at
the request of a manufacturer or manufacturers under 40 CFR 702.37,
will be conducted in accordance with this part, except that risk
evaluations that are initiated prior to the effective date of this rule
will be conducted in accordance with this part to the maximum extent
practicable.
    (b) Percentage Requirements. The Agency will ensure that, of the
number of chemical substances that undergo risk evaluation under 15
U.S.C. 2605(b)(4)(C)(i), the number of chemical substances undergoing
risk evaluation under 15 U.S.C. 2605(b)(4)(C)(ii) is not less than 25%,
if sufficient requests that comply with 40 CFR 702.37 are made by
manufacturers, and not more than 50%.
    (c) Manufacturer Requests for Work Plan Chemical Substances.
Manufacturer requests for risk evaluations, described in 40 CFR
702.35(a), for chemical substances that are drawn from the 2014 update
of the TSCA Work Plan for Chemical Assessments or its relevant and
applicable successor document will be granted at the discretion of the
Agency. Such evaluations are not subject to the percentage requirements
in 40 CFR 702.35(b).

Sec.  702.37   Submission of manufacturer requests for risk
evaluations.

    (a) General Provision. Any request for EPA to conduct a risk
evaluation on a chemical substance pursuant to this part must comply
with all the procedures and criteria in this section to be eligible to
be granted by EPA. A request will meet EPA's criteria if the request
includes or references all the information that is necessary for EPA to
conduct a risk evaluation addressing all the circumstances that
constitute conditions of use of the chemical substance within the
meaning of TSCA section 3 (i.e., all circumstances under which the
chemical substance is intended, known, or reasonably foreseen to be
manufactured, processed, distributed in commerce, used, or disposed
of).
    (b) Method for Submission. One or more manufacturers of a chemical
substance can request that EPA conduct a risk evaluation on the
chemical substance by providing all the following information:
    (1) Name, mailing address, and contact information of the entity
(or entities) submitting the request. If more than one manufacturer
submits the request, all individual manufacturers must provide their
contact information.
    (2) Full information on the chemical identity of the chemical
substance that is the subject of the request. At a minimum, this
includes, all known names of the chemical substance, including common
or trades names, chemical identity, CAS number, and molecular structure
of the chemical substance.
    (3) A complete list of the reasonably available information that is
consistent with the standards in TSCA section 26(h) and that is
relevant to whether the chemical substance presents an unreasonable
risk of injury to health or the environment. The list must be
accompanied by an explanation as to why such information is adequate to
permit EPA to complete a risk evaluation addressing all the
circumstances that constitute conditions of use of the chemical
substance within the meaning of TSCA section 3 (i.e., all circumstances
under which the chemical substance is intended, known, or reasonably
foreseen to be manufactured, processed, distributed in commerce, used,
or disposed of). The request need not include copies of the
information; citations are sufficient. The request must include or
reference all reasonably available information on the health and
environment hazard(s) of the chemical substance, health and
environmental exposure(s), and exposed population(s). At a minimum this
must include information relevant to the following:
    (i) The chemical substance's hazard and exposure potential;
    (ii) The chemical substance's persistence and bioaccumulation;
    (iii) Potentially exposed or susceptible subpopulations they
believe to be relevant and that EPA should evaluate in the risk
evaluation;
    (iv) Whether there is any storage of the chemical substance near
significant sources of drinking water;
    (v) The chemical substance's conditions of use or significant
changes in conditions of use;
    (vi) The chemical substance's production volume or significant
changes in production volume; and
    (vii) Any other information relevant to the risks potentially
presented by the chemical substance.
    (4) The request must include a commitment to provide to EPA any
referenced information upon request. In addition, if the manufacturer
previously conducted its own risk assessment of the chemical substance,
or possesses or can reasonably obtain any other pre-existing risk
assessment, the request must include a commitment to provide such
assessments to EPA upon request.
    (5) A signed certification that all information contained in the
request is accurate and complete, as follows:

    I certify under penalty of law that this document and all
attachments were prepared under my direction or supervision and the
information contained therein, to the best of

my knowledge is, true, accurate, and complete and I have not
withheld any relevant information. I am aware there are significant
penalties for submitting incomplete, false and/or misleading
information, including the possibility of fine and imprisonment for
knowing violations.

    (c) Optional Elements. A manufacturer may provide evidence to
demonstrate that restrictions imposed by one or more States have the
potential to have a significant impact on interstate commerce or health
or the environment, and that as a consequence the request is entitled
to preference pursuant to 15 U.S.C. 2605(b)(4)(E)(iii).
    (d) Confidential Business Information. (1) Persons submitting a
request under this subpart are subject to EPA confidentiality
regulations at 40 CFR part 2, subpart B.
    (2) In submitting a claim of confidentiality, a person must certify
the truth of the following statements concerning all information
claimed as confidential:

    I hereby certify to the best of my knowledge and belief that all
information entered on this form is complete and accurate. I further
certify that, pursuant to 15 U.S.C. 2613(c), for all claims for
confidentiality made with this submission, all information submitted
to substantiate such claims is true and correct, and that it is true
and correct that
    (i) My company has taken reasonable measures to protect the
confidentiality of the information;
    (ii) I have determined that the information is not required to
be disclosed or otherwise made available to the public under any
other Federal law;
    (iii) I have a reasonable basis to conclude that disclosure of
the information is likely to cause substantial harm to the
competitive position of my company; and
    (iv) I have a reasonable basis to believe that the information
is not readily discoverable through reverse engineering.

    (3) Each claim of confidentiality, other than a claim pertaining to
information described in TSCA section 14(c)(2), must be accompanied by
a substantiation in accordance with 40 CFR 2.204(e)(4).
    (4) Manufacturers must supply a structurally descriptive generic
name where specific chemical identity is claimed as CBI.
    (5) Any knowing and willful misrepresentation is subject to
criminal penalty pursuant to 18 U.S.C. 1001.
    (e) EPA Process for Evaluating Manufacturer Requests. (1) Review
for completeness. Upon receipt of the request, EPA will verify that the
request is facially valid, i.e., that information has been submitted
that is consistent with the requirements in 40 CFR 702.37(b) through
(d). EPA will inform the submitting manufacturer(s) if EPA has
determined that the request is incomplete and cannot be processed.
Complete requests will be processed as described in this subpart.
    (2) Public notice and comment. Within 30 business days of receiving
a request that EPA has determined to be valid under paragraph (e)(1) of
this section, EPA will submit for publication the receipt of the
request in the Federal Register, open a docket for that request and
provide no less than a 30 calendar day public comment period, during
which time the public may submit comments and information relevant to
whether the chemical substance presents an unreasonable risk of injury
to health or the environment under the conditions of use. In
particular, comments identifying any information gaps in the request
(e.g., any conditions of use not identified in the request).
    (3) Supplementation of original request. (i) At any time prior to
the end of the comment period, manufacturer(s) may supplement the
original request with any new information it receives/obtains.
    (ii) At any point prior to the completion of a risk evaluation
conducted on a chemical substance at the request of a manufacturer(s),
manufacturer(s) are required to supplement the original request upon
receipt of information that meets the criteria in 15 U.S.C. 2607(e) and
40 CFR 702.37, or other information that has the potential to change
EPA's evaluation of the risk of the chemical substance. Such
information must be submitted within 30 calendar days of discovery.
    (4) EPA determination. Within 9 months of the end of the comment
period provided in paragraph (e)(2) of this section, EPA will review
the request along with any additional information received during the
comment period to determine whether the request meets the criteria and
requirements of 40 CFR 702.37. EPA will notify the submitting
manufacturer(s) of its determination.
    (i) Request is lacking required information. (A) The
manufacturer(s) have 60 calendar days from receipt of EPA's
determination to submit any additional information identified as
lacking in the notification.
    (B) Failure to submit the additional information will be considered
to be a withdrawal of the request to initiate a risk evaluation on the
named chemical substance.
    (C) Notwithstanding any such withdrawal, manufacturer(s) may submit
a subsequent request on the same chemical substance.
    (ii) Compliant request. EPA will initiate a risk evaluation for all
requests for non-TSCA Work Plan Chemicals that meet the criteria in
this subpart, until EPA determines that the number of manufacturer-
requested chemical substances undergoing risk evaluation is equal to
25% of the High-Priority Substances identified in subpart A as
undergoing risk evaluation. Once that level has been reached, EPA will
initiate one new manufacturer-requested risk evaluation for each
manufacturer-requested risk evaluation completed, as needed to ensure
that the number of manufacturer-requested risk evaluations is equal to
at least 25% of the High-Priority substances risk evaluation.
    (5) Preferences. In conformance with 40 CFR 702.35(c), in
evaluating requests for TSCA Work Plan Chemicals and requests for non-
TSCA Work Plan chemicals in excess of the 25% threshold in paragraph
(e)(4)(ii) of this section, EPA will give preference to requests for
risk evaluations on chemical substances:
    (i) That demonstrate that restrictions imposed by one or more
States have the potential to have a significant impact on interstate
commerce, health or the environment.
    (ii) EPA will also give preference to requests where EPA has
determined there are relatively high estimates of hazard and/or
exposure for the chemical substance.
    (iii) Any other factor EPA determines to be relevant.
    (6) Conditions of use considered. EPA will conduct the risk
evaluation on all of the conditions of use of a chemical substance
undergoing risk evaluation at the request of a manufacturer, as
determined through the scoping process outlined in 40 CFR 702.39(c).
    (7) No preferential treatment. EPA will not expedite or otherwise
provide special treatment to a risk evaluation conducted as a result of
a manufacturer request.
    (f) Fees. Manufacturers must pay fees to support risk evaluations
under 15 U.S.C. 2605(b)(4)(C)(ii).

Sec.  702.39   Evaluation Requirements and Peer Review Procedures.

    (a) Considerations. (1) Each risk evaluation will include the
following components: a Scope, including a Conceptual Model and an
Analysis Plan; a Hazard Assessment; an Exposure Assessment; a Risk
Characterization; and a Risk Determination.
    (2) Existing EPA guidance, where available and relevant, will be
used in conducting the risk evaluation. In addition, other
scientifically relevant methods or guidance may be used in a risk
evaluation.

    (3) Where appropriate, a risk evaluation may be conducted on a
category of chemical substances. EPA will determine whether to conduct
an evaluation on a category of chemical substances, and the composition
of the category based on the considerations listed in 15 U.S.C.
2625(c). In addition to the factors specifically enumerated in that
provision, EPA may consider the hazards and exposures associated with
the category of chemical substances, and the populations likely to be
exposed.
    (4) EPA will ensure that all supporting analyses and components of
the risk evaluation are suitable for their intended purpose, and well-
tailored to the problems and decision at hand, in order to inform the
development of a technically sound determination as to whether a
chemical substance presents an unreasonable risk of injury to health or
the environment, based on the weight of the scientific evidence.
    (5) The extent to which EPA will refine its evaluations for
particular conditions of use in any risk evaluation will vary as
necessary to determine whether a chemical substance presents an
unreasonable risk of injury to health or the environment. To the extent
a determination as to the level of risk presented by a condition of use
can be made, for example, by the use of accepted science policies
(e.g., defaults assumptions or uncertainty factors), and models or
screening methodologies, EPA may determine that no further information
or analysis is needed to complete its risk evaluation of the use(s).
    (6) EPA may conduct a risk evaluation on a chemical substance in
phases to allow the Agency to proceed with risk management on
particular conditions of use. For example, EPA may determine that a
chemical substance presents an unreasonable risk of injury to health or
the environment under one or more conditions of use, and address such
unreasonable risk through rulemaking under TSCA section 6(a), while
other conditions of use remain under evaluation. In all cases in which
EPA conducts its risk evaluations in phases, EPA will nevertheless
complete a full risk evaluation of the chemical substance for all of
the conditions of use identified through the scoping process in 40 CFR
702.39(c) within the time frame in 40 CFR 702.43(d).
    (7) In evaluating chemical substances that are metals or metal
compounds, EPA will use the Framework for Metals Assessment of the
Office of the Science Advisor, Risk Assessment Forum dated March 2007,
or a successor document that addresses metal risk assessment and is
peer reviewed by the Science Advisory Board.
    (b) Information and information sources. (1) EPA will base each
risk evaluation on reasonably available information.
    (2) EPA generally expects to initiate a risk evaluation for a
chemical substance only when EPA believes that all or most of the
information necessary to perform the risk evaluation already exists and
is reasonably available. EPA expects to use its authorities under the
Act, and other information gathering authorities, when necessary to
generate the information needed to perform a risk evaluation for a
chemical substance before initiating the risk evaluation for such
substance. EPA will use such authorities on a case-by-case basis during
the performance of a risk evaluation to obtain or generate information
as needed to ensure that EPA has adequate, reasonably available
information to perform the evaluation.
    (3) Among other sources of information, the Agency will consider
information and advice provided by the Science Advisory Committee on
Chemicals established pursuant to 15 U.S.C. 2625.
    (4) In conducting risk evaluations, EPA will rely on an appropriate
combination of information, accepted science policies (e.g., defaults
and uncertainty factors), models and screening methodologies. The
balance of information, accepted science policies models, and screening
methodologies used in risk evaluation will be informed by the deadlines
specified in TSCA section 6(b)(4)(G) for completing such evaluations.
It will also be informed by consideration of the extent to which
additional information would reduce the uncertainty in determining
whether a chemical substance presents an unreasonable risk of injury to
health or the environment.
    (5) Where appropriate, to the extent practicable, and
scientifically justified, EPA will use information generated without
the use of testing on vertebrates in performing risk evaluation.
    (c) Scope of the risk evaluation. EPA will determine the scope of
the risk evaluation to be conducted for each chemical substance based
on all of the following:
    (1) EPA will identify those uses that constitute the conditions of
use that will be assessed during the risk evaluation. Those uses shall
be all circumstances under which the Agency determines that the
chemical substance is intended, known, or reasonably foreseen to be
manufactured, processed, distributed in commerce, used, or disposed of.
    (2) When determining the scope, EPA will identify the exposed
individuals and populations, including any potentially exposed or
susceptible subpopulations as identified by the Agency that EPA plans
to evaluate; the ecological characteristics that EPA plans to evaluate;
and the hazards to health and the environment that EPA plans to
evaluate.
    (3) The combination of reasonably available information, accepted
science policies (e.g., defaults and uncertainty factors), models, and
screening methodologies that EPA plans to use in the risk evaluation
will be documented.
    (4) Conceptual model. (i) The scope documents will include a
Conceptual Model that describes actual or predicted relationships
between the chemical substance and human and environmental receptors.
    (ii) The Conceptual Model will identify human and ecological health
endpoints the EPA plans to evaluate for the exposure scenarios EPA
plans to evaluate.
    (iii) Conceptual Model development will consider the life cycle of
the chemical substance, including manufacture, processing, distribution
in commerce, storage, use, and disposal.
    (5) Analysis plan. (i) The scope documents will include an analysis
plan that identifies the approaches, methods, and/or metrics that the
EPA plans to use to assess exposures, effects, and risk, including
associated uncertainty and variability for each risk evaluation. The
analysis plan will also identify the strategy for using information,
accepted science policies, models, and screening methodologies.
    (ii) Hypotheses about the relationships described in the conceptual
model will be described. The relative strengths of (any) competing
hypotheses will be evaluated to determine the appropriate risk
assessment approaches.
    (6) Developing the Scope. (i) Draft scope. For each risk evaluation
to be conducted EPA will publish a document in the Federal Register
that specifies the draft scope of the risk evaluation the Agency plans
to conduct. The document will address the elements in paragraphs (c)(1)
through (5) of this section.
    (ii) Timeframes. EPA generally expects to publish the draft scope
no later than 3 months from the initiation of the risk evaluation
process for the chemical substance, and to allow a period of 30
calendar days during which interested persons may submit comment on
EPA's draft risk evaluation scope. EPA will open a docket to facilitate
receipt of public comments.
    (iii) Public comments. All comments that could be raised on the
matters addressed and issues presented in the

published risk evaluation scope document must be presented during this
comment period. Any issues not raised at this time will be considered
to have been waived, and may not form the basis for an objection or
challenge in any subsequent administrative or judicial proceeding.
    (iv) Final scope. (A) The Agency will, no later than 6 months after
the initiation of a risk evaluation, publish a document in the Federal
Register that specifies the final scope of the risk evaluation the
Agency plans to conduct. The document shall address the elements in
paragraphs (c)(1) through (5) of this section.
    (B) For a chemical substance designated as a High-Priority
Substance under 40 CFR part 702 subpart A, EPA will not publish the
final scope of the risk evaluation until at least 12 months have