[Federal Register Volume 82, Number 138 (Thursday, July 20, 2017)]
[Rules and Regulations]
[Pages 33726-33753]
[FR Doc No: 2017-14337]

Vol. 82

Thursday,

No. 138

July 20, 2017

Part III

Environmental Protection Agency

-----------------------------------------------------------------------

40 CFR Part 702

Procedures for Chemical Risk Evaluation Under the Amended Toxic
Substances Control Act; Procedures for Prioritization of Chemicals for
Risk Evaluation Under the Toxic Substances Control Act; Guidance To
Assist Interested Persons in Developing and Submitting Draft Risk
Evaluations Under the Toxic Substances Control Act; Notice of
Availability; Final Rules and Notice

Federal Register / Vol. 82 , No. 138 / Thursday, July 20, 2017 /
Rules and Regulations

-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 702

[EPA-HQ-OPPT-2016-0654; FRL-9964-38]
RIN 2070-AK20

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

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: As required under section 6(b)(4) of the Toxic Substances
Control Act (TSCA), EPA is issuing a rule that establishes 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. This process incorporates
the science requirements of the amended statute, including best
available science and weight of the scientific evidence. 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 rule identifies the steps of a risk
evaluation process including: scope, hazard assessment, exposure
assessment, risk characterization, and finally a risk determination.
This process will be used for the first ten chemical substances
undergoing evaluation from the 2014 update of the TSCA Work Plan for
Chemical Assessments (to the maximum extent practicable). 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 a manufacturer request, will
always be subject to this process. The final rule also includes the
required ``form and criteria'' applicable to such manufacturer
requests.

DATES: This final rule is effective September 18, 2017.

ADDRESSES: The docket for this action, identified by docket
identification (ID) number EPA-HQ-OPPT-2016-0654, is available at
http://www.regulations.gov or at the Office of Pollution Prevention and
Toxics Docket (OPPT Docket), Environmental Protection Agency Docket
Center (EPA/DC), West William Jefferson Clinton Bldg., Rm. 3334, 1301
Constitution Ave. NW., Washington, DC. The Public Reading Room is open
from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal
holidays. The telephone number for the Public Reading Room is (202)
566-1744, and the telephone number for the OPPT Docket is (202) 566-
0280. Please review the visitor instructions and additional information
about the docket 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 establishing requirements on the Agency. However,
this rule also includes the process and criteria that manufacturers
(including importers) must 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 establishing, by rule, the process by which the Agency will
conduct risk evaluations on chemical substances under TSCA. The rule
identifies the necessary components of a risk evaluation, including a
scope (including a conceptual model and an analysis plan), a hazard
assessment, an exposure assessment, a risk characterization, and a risk
determination. The rule also establishes the process by which
manufacturers would request an Agency-conducted risk evaluation, and
the criteria by which the EPA will evaluate such requests. This rule
also incorporates the statutory science requirements, including best
available science and weight of the scientific evidence.

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

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

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

    The incremental impacts of this action are the result of the
process and requirements that manufacturers (including importers) must
perform if they elect to submit a chemical substance for a risk
evaluation. EPA has estimated 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 which is
available in the docket, is discussed in Unit V. and is briefly
summarized here. (Ref. 1).
    The total estimated annual burden is 419.2 hours and $282,861,
which is based on an estimated per request burden of 83.8 hours.
    In addition, EPA's evaluation of the potential costs associated
with this action is discussed in Unit V. Since this rule focuses on the
activities that a manufacturer must perform, the estimated incremental
costs are expected to be de minimis.

II. Background

A. 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
completion of the risk evaluation. The law also requires

that EPA operate in a manner that is consistent with the best available
science and make decisions based on the weight of the scientific
evidence. 15 U.S.C. 2625(h) and (i).
    1. Chemical substances to undergo risk evaluation. TSCA section
6(b) identifies the chemical substances that are subject to this
process; these are: (1) The ten chemical substances the Agency was
required to identify from the 2014 update to the TSCA Work Plan within
the first 180 calendar days after the signing of TSCA); (2) the
chemical substances determined to be High-Priority Substances through
the prioritization process published elsewhere in this Federal
Register; and (3) chemicals selected in response to a manufacturer
request that meets the criteria established by this rule. 15 U.S.C.
2605(b)(4)(C). Assuming EPA receives a sufficient number of compliant
requests, the statute specifies that EPA shall ensure that the number
of manufacturer-requested evaluations is not less than 25 percent and
not more than 50 percent of the number of the on-going ``High
Priority'' risk evaluations. 15 U.S.C 2605(b)(4)(E). 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 risk evaluations for chemical
substances on the 2014 update of the TSCA Work Plan (Ref. 2) will be
granted at the discretion of the Administrator, and 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 EPA conduct a risk evaluation on a
substance that they manufacture. 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 if
it determines that it 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, EPA is directed to
give preference to manufacturer requests for which 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).
    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 EPA expects to conduct,
which includes the hazards, exposures, conditions of use, and the
potentially exposed or susceptible subpopulations that EPA expects to
consider. 15 U.S.C 2605(b)(4)(D). The statute further provides that the
scope of the risk evaluation must be published no later than six months
after the initiation of the risk evaluation. Id.
    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; and (4)
describe the weight of the scientific evidence for the identified
hazards and exposure. 15 U.S.C. 2605(b)(4)(F)(i), and (iii)-(v). The
risk evaluation must not consider costs or other non-risk factors. 15
U.S.C. 2605(b)(4)(F)(ii).
    4. Science requirements. TSCA section 26 requires that, to the
extent that EPA makes a decision based on science under TSCA sections
4, 5, or 6, EPA must use scientific standards and base those decisions
on the best available science and on the weight of the scientific
evidence. 15 U.S.C. 2625(h) and (i). TSCA does not however explicitly
define either of these terms. Section 26(h) lists factors for the
Agency to consider, as applicable, in employing best available science.
These are: (1) The extent to which the scientific information,
technical procedures, measures, methods, protocols, methodologies, or
models employed to generate the information are reasonable for and
consistent with the intended use of the information; (2) the extent to
which the information is relevant for the Administrator's use in making
a decision about a chemical substance or mixture; (3) the degree of
clarity and completeness with which the data, assumptions, methods,
quality assurance, and analyses employed to generate the information
are documented; (4) the extent to which the variability and uncertainty
in the information, or in the procedures, measures, methods, protocols,
methodologies, or models, are evaluated and characterized; and (5) the
extent of independent verification or peer review of the information or
of the procedures, measures, methods, protocols, methodologies, or
models. As statutory requirements, they apply to EPA's decisions under
TSCA sections 4, 5, and 6.
    5. Timeframe. TSCA requires that the risk evaluation process last
no longer than three years, with a possible additional six-month
extension. 15 U.S.C. 2605(b)(4)(G).
    6. Opportunities for public participation. The statute requires
that the Agency allow for no less than a 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).
    7. 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. 3) or a successor
document that addresses metals risk assessment and is peer- reviewed by
the Science Advisory Board.
    8. Non-vertebrate testing. Although not an explicit section 6
requirement, TSCA imposes new requirements on EPA regarding the
reduction of vertebrate testing. 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). Under the risk evaluation process, EPA may
require development of new information relating to a chemical
substance. Prior to developing this information EPA must first take
into account reasonably available existing information, and
additionally, must encourage and facilitate the use of test methods
that reduce or replace the use of vertebrate animals, group chemicals
into categories to reduce testing, and encourage the formation of
industry consortia to jointly conduct testing and other data gathering
to avoid unnecessary duplication of tests.

B. Overview of Final Rule

    This final rule incorporates all the elements required by statute,
as discussed in Unit II.A., some additional criteria the Agency plans
to include and

consider, clarifications for greater transparency, and additional
procedural steps to ensure effective and transparent implementation. In
response to public comments on the proposal, EPA is, among other
things: (1) Adding direct references in the final rule to acknowledge
the Agency's commitment to implementing the best available science and
weight of the scientific evidence provisions in TSCA, (2) codifying the
Agency's commitment to interagency collaboration, (3) allowing
manufacturers to limit their requests for EPA-conducted risk
evaluations to one or more specified conditions of use, and (4)
allowing for risk determinations to be made on individual conditions of
use or categories of conditions of use at any time once the Final Scope
is published.
    EPA intends that the provisions of this rule be severable. In the
event that any individual provision or part of this rule is
invalidated, EPA intends that this would not render the entire rule
invalid, and that any individual provisions that can continue to
operate will be left in place.

III. Discussion of Final Rule and Response to Comments

A. Policy Objectives

    The risk evaluation process under TSCA will provide the basis for
the EPA's determination as to whether a chemical substance presents an
unreasonable risk of injury to health or the environment. The overall
objective of this action is to codify the process by which the Agency
evaluates risks from chemical substances under TSCA section 6. In this
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 and to provide predictability in how
they will be conducted. However, EPA is not establishing 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 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. 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
Administrator, 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).
    In the proposed rule, EPA explained that it interpreted TSCA to
require 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. EPA further
proposed that the conditions of use would need to encompass all known,
intended, and reasonably foreseen activities associated with the
subject chemical substance. EPA also noted, however, that a use or
other activity constitutes a condition of use under the definition only
if EPA determines that it does, and that EPA has authority to exercise
judgment in making its determination of whether a condition of use is
known, intended, or reasonably foreseen.
    This was one of the issues on which EPA received the most comments.
Comments covered a number of considerations regarding conditions of
use: How the Agency will define ``the conditions of use'', how the
Agency will scope conditions of use (e.g., are there conditions of use
which will not be included in the Scope of the risk evaluation for one
reason or another), and finally how the Agency will treat the
conditions of use identified in the scope, in the final risk
determination. EPA discusses the first two considerations in this unit;
the third consideration will be discussed in the risk determination
Unit III.G.1.e.
    In defining conditions of use, many commenters raised concern about
EPA's interpretation that ``the conditions of use'' must include ``all
conditions of use.'' Concerns were raised in this regard was
specifically about the ability of EPA to meet the statutory risk
evaluation deadlines if all intended, known and reasonably foreseen
activities must be considered conditions of use, and that attempting to
identify every activity relating to the chemical substance was
unnecessary and impractical. Concerns were also raised about ensuring
that EPA can act promptly to address any unreasonable risks identified
for particular conditions of use. Commenters who agreed with the
proposed interpretation of ``all conditions of use'' stated that the
law in a number of locations signals the intent that EPA evaluate all
activities associated with the chemical. The identified locations
include the section on Final Agency Action which states that decisions
will be on a ``chemical substance'' without mention of condition of
use, indicating that EPA must consider all conditions of use (15 U.S.C.
2605(i)), and the requirement to account for the ``likely duration,
intensity, frequency, and number of exposures under the conditions,
where relevant'' (15 U.S.C. 2605(b)(4)(F)(iv)), which refers to the
consideration of whether a combination of activities involving the
chemical substance presents a risk, and therefore EPA must look at the
full spectrum of the activities associated with a chemical (all
intended, known, or reasonably foreseen manufacturing, processing,
distribution, use and disposal).
    As EPA acknowledged in the proposal, different interpretations of
the statute are possible. Given the strength and variety of the
concerns presented in the comments, EPA has reevaluated its proposal.
Accordingly, EPA went back to the direction on risk evaluation provided
in section 6(b) of the statute and legislative history, and developed
an approach to the term, ``the conditions of use'' that is firmly
grounded in the law, while accounting for the various policy
considerations necessary for effective implementation of section 6.
EPA's final approach is informed in part by the legislative history of
the amended TSCA, which explicitly states that the Agency is given the
discretion to determine the conditions of use that the Agency will
address in its evaluation of the priority chemical, in order to ensure
that the Agency's focus is on the conditions of use that raise the
greatest potential for risk. See, June 7, 2016 Cong Rec, S3519-S3520.
    In sum, EPA's overall objective of this rule is to ensure that it
is able to focus on conducting a timely, relevant, high-quality, and
scientifically credible evaluation of a chemical substance as a whole,
and that it always includes an evaluation of the conditions of use that
raise greatest potential for risk. EPA wants also to ensure that the
Agency can effectively assess, and where necessary, regulate chemical
substances, within the statutory deadlines. These same principles will
also serve to guide EPA's implementation of the procedures.
    To begin, EPA will identify the ``circumstances'' that constitute
the ``conditions of use'' for each chemical substance on a case-by-case
basis. TSCA

defines a chemical's ``conditions of use'' as ``the circumstances, as
determined by the Administrator, 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).
While EPA interprets this as largely a factual determination--i.e., EPA
is to determine whether a chemical substance is actually involved in
one or more of the activities listed in the definition--the
determination will inevitably involve the exercise of some discretion.
As EPA interprets the statute, the Agency is to exercise that
discretion consistent with the objective of conducting a technically
sound, manageable evaluation to determine whether a chemical
substance--not just individual uses or activities--presents an
unreasonable risk. In that regard, EPA will be guided by its best
understanding, informed by legislative text and history, of the
circumstances of manufacture, processing, distribution in commerce, use
and disposal Congress intended EPA to consider in risk evaluations.
    For most chemical substances EPA expects to make this determination
primarily during the prioritization of a chemical substances. For
chemicals that are the subject of a manufacturer request (which are not
subject to prioritization), EPA intends to make this determination as
part of the process for determining whether the request satisfies EPA's
criteria, as discussed in greater detail in Unit III.G.
    Although EPA intends this to primarily be a case-by-case
determination, as discussed in greater detail in Unit III.B.1, based on
legislative history, statutory structure and other evidence of
Congressional intent, EPA has identified certain activities that may
generally not be considered to be conditions of use. As EPA gains
experience in conducting risk evaluations, EPA may determine that other
activities do not constitute conditions of use, based on the same type
of analysis of Congressional intent. Second, in developing the scope of
the risk evaluation, 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 is not required to consider all
conditions of use. Consequently, EPA may, on a case-by-case basis,
exclude certain activities that EPA has determined to be conditions of
use in order to focus its analytical efforts on those exposures that
are likely to present the greatest concern, and consequently merit an
unreasonable risk determination. For example, EPA may, on a case-by-
case basis, exclude uses that EPA has sufficient basis to conclude
would present only ``de minimis'' exposures. This could include uses
that occur in a closed system that effectively precludes exposure, or
use as an intermediate. During the scoping phase, EPA may also exclude
a condition of use that has been adequately assessed by another
regulatory agency, particularly where the other agency has effectively
managed the risks. EPA elaborates further on this step in Unit III.B.2.
    EPA intends to identify any conditions of use excluded during these
first and second steps in the draft scope, along with the basis for
EPA's preliminary determination, to provide the public with an
opportunity to comment on the exclusions. The final scope, which
specifies the conditions of use that EPA expects to consider in the
risk evaluation, will also identify whether particular conditions of
use have been excluded as a result of this process, along with the
Agency's rationale.
    Finally, consistent with its original proposal, EPA may conduct its
risk evaluations in stages. While the proposal only addressed the
situation in which EPA determined that risk mitigation was necessary to
address an unreasonable risk from a chemical substance under certain
conditions of use, EPA has extended the logic in the final rule to
apply whenever EPA has sufficient information to support a
determination as to whether a chemical substance presents an
unreasonable risk under particular conditions of use. Thus, at any
point after EPA has issued its final scope document, in cases where EPA
has sufficient information to determine whether or not the chemical
substance presents an unreasonable risk under particular conditions of
use, the Agency may issue an early determination for that subset of
conditions of use, while EPA continues to evaluate the remaining
conditions of use. All early determinations would be portions of the
final, complete risk evaluation and would therefore be made using the
procedures applicable to TSCA risk evaluations established in this
rule. This would include the requirement that EPA publish a draft risk
evaluation for no less than a 60-day public comment period, and the
regulatory requirement for peer review. This may result in separate
peer reviews for the separate determinations.
    In the interest of efficiency, EPA envisions that, in general, it
would attempt to identify the subset of conditions of use that are
candidates for an early determination as part of the draft scope
document. In such cases, EPA may publish its draft risk evaluation for
public comment along with the final Scope document. Depending on the
information received during the comment period, EPA would either
determine that it needed to continue to evaluate those conditions of
use, or proceed to issue final determinations for those conditions of
use.
    1. Exclusions from the Definition of Conditions of Use. As noted,
the statute grants EPA the discretion to determine the circumstances
that are appropriately considered to be the chemical's ``conditions of
use.'' In exercising that discretion, for example, EPA would not
generally consider that a single unsubstantiated or anecdotal statement
(or even a few isolated statements) on the internet that a chemical can
be used for a particular purpose would necessitate concluding that this
represented part of the chemical substance's ``conditions of use.'' As
a further example, although the definition could be read literally to
include all intentional misuses (e.g., inhalant abuse), as a ``known''
or ``reasonably foreseen'' activity in some circumstances, EPA does not
generally intend to include such activities in either a chemical
substance's prioritization or risk evaluation. EPA's judgment is
supported by the legislative history, and public comment suggesting
that ``the term `conditions of use' is not intended to include
`intentional misuse' of chemicals.'' See, for example Senate Report
114-67, page 7. Without these exclusions, the concept of ``conditions
of use'' would likely result in no meaningful limitation on EPA risk
evaluations, and risk evaluations could present unmanageable
challenges--an outcome that EPA does not expect Congress intended.
    Similarly, the statute is ambiguous as to whether the conditions of
use identified by EPA should include the circumstances associated with
activities that do not reflect ongoing or prospective manufacturing,
processing, or distribution, which EPA will refer to as ``legacy
uses.'' The statute is also ambiguous as to disposals from such uses
(e.g., the future disposal of insulation that contains a chemical
substance that is no longer manufactured, processed, or distributed for
use in insulation), which EPA will call ``associated disposal,'' and
disposals that have already occurred (e.g., a chemical substance
currently in a landfill or in groundwater), which EPA will call
``legacy disposal.'' No statutory text expressly addresses these
issues. The absence of express statutory

text on legacy use, associated disposal, and legacy disposal, as well
as the plain language in ``conditions of use'' charging EPA to
determine the circumstances appropriately considered to be the
``conditions of use,'' leads the Agency to resolve the statutory
ambiguity by considering all the tools of statutory interpretation
(e.g., reliance on legislative history, and general maxims of statutory
construction).
    EPA interprets the mandates under section 6(a)-(b) to conduct risk
evaluations and any corresponding risk management to focus on uses for
which manufacturing, processing, or distribution in commerce is
intended, known to be occurring, or reasonably foreseen to occur (i.e.,
is prospective or on-going), rather than reaching back to evaluate the
risks associated with legacy uses, associated disposal, and legacy
disposal, and interprets the definition of ``conditions of use'' in
that context. For instance, the conditions of use for purposes of
section 6 might reasonably include the use of a chemical substance in
insulation, where the manufacture, processing, or distribution in
commerce for that use is prospective or on-ongoing, but would not
include the use of the chemical substance in previously installed
insulation, if the manufacture, processing or distribution for that use
is not prospective or on-going. In other words, EPA interprets the risk
evaluation process of section 6 to focus on the continuing flow of
chemical substances from manufacture, processing and distribution in
commerce into the use and disposal stages of their lifecycle. EPA
believes the statute is better interpreted to focus on the prospective
flow of the chemical substance. That said, in a particular risk
evaluation, EPA may consider background exposures from legacy use,
associated disposal, and legacy disposal as part of an assessment of
aggregate exposure or as a tool to evaluate the risk of exposures
resulting from non-legacy uses.
    Overall, EPA has determined that the statutory text better supports
a prospective interpretation. Section 3 defines the ``conditions of
use'' as ``the circumstances, as determined by the Administrator, under
which a chemical substance is intended, known, or reasonably foreseen
to be manufactured, processed, distributed in commerce, used, or
disposed of.'' (emphasis added). The ``to be'' phrasing suggests that
the term is focused prospectively. Moreover, throughout the legislative
history, there are a number of references to TSCA as a statute for the
regulation of chemicals ``in commerce,'' suggesting the intent to focus
on current activities associated with chemicals rather than legacy
issues. In addition, EPA notes that section 6(a) of TSCA does not
authorize EPA to directly regulate non-commercial use, meaning that EPA
would not have an effective tool to address risks found to arise from
uses in consumer settings if there were no on-going commercial
manufacture, processing or distribution.
    EPA's interpretation finds support in the general presumption
against construing a statute (or implementing regulation) to be
retroactive or have retrospective effect. While Congress can make a law
retroactive, absent clear intent from Congress, courts will not hold a
statute to be retroactive, or uphold an agency regulation that seeks to
have such an effect. Republic of Iraq v. Beaty, 556 U.S. 848 at 862
(2009) (citing to Landgraf v. Usi Film Products, 511 U.S. 244, 267-68
(1994). See also, Bowen v. Georgetown Univ. Hosp., 488 U.S. 204, 208
(1988) (citing several sources). This general presumption also extends
to statutes that affect ``vested rights and past transactions,'' which
have been considered to be retroactive (or ``retrospective'') in
nature. E.g., Landgraf, 511 U.S. at 268-69, 296 (quotation marks and
citations omitted) (citing several other Supreme Court cases using
alternate formulations of this principle).
    Finally, even if these activities were not excluded from the
definition of conditions of use, EPA generally expects that it would
exercise its discretion under section 6(b)(4)(D) to exclude them from
the scope of risk evaluations, as discussed in section B.2., below.
    2. Conditions of use that may be excluded from the Scope of the
risk evaluation. In exercising its discretion under section 6(b)(4)(D),
EPA believes it is important for the Agency to have the discretion to
make reasonable, technically sound scoping decisions in light of the
overall objective of determining whether chemical substances in
commerce present an unreasonable risk. For example, EPA intends to
exercise discretion in addressing circumstances where the chemical
substance subject to scoping is unintentionally present as an impurity
in another chemical substance that is not the subject of the pertinent
scoping. In some instances, it may be most appropriate from a technical
and policy perspective to evaluate the potential risks arising from a
chemical impurity within the scope of the risk evaluations for the
impurity itself. In other cases, it may be more appropriate to evaluate
such risks within the scope of the risk evaluation for the separate
chemical substances that bear the impurity. (EPA has previously taken
an analogous approach, in requiring chemical testing of certain
chemical substances under 40 CFR part 766, based on the potential for
the chemical substance to be manufactured in such a manner as to be
contaminated with dioxins.) In still other cases, EPA may choose not to
include a particular impurity within the Scope of any risk evaluation,
where EPA has a basis to foresee that the risk from the presence of the
impurity would be `de minimis' or otherwise insignificant. Finally, as
stated, EPA received a number of comments offering ideas regarding
conditions of use that should not be considered in a risk evaluation,
for example, on the ground that certain uses are not ``reasonably
foreseen.'' Some of the many uses that commenters asked to be excluded
from a risk evaluation include: Uses where other agencies hold
jurisdiction, misuse, illegal use, speculative future conditions of
use, uses that are inconsistent with labeling requirements or PPE
requirements, chemicals used in articles or replacement parts, uses
that are inconsistent with manufacturers' instructions, accidental
conditions of use of a chemical, or uses where residuals from an
industrial process are completely destroyed. In connection with these
suggestions, several of these commenters also requested that EPA
clearly define precisely how the Agency will determine whether a
condition of use is ``known or reasonably foreseen.''
    At this stage of EPA's implementation, EPA believes that it would
be premature to definitively exclude a priori specific conditions of
use from risk evaluation. For the same reason, EPA believes that it
would be premature to establish a specific test or restrictive
definition to determine whether a condition of use is ``reasonably
foreseen.'' The Agency is committed to exercising its discretion to
determine the conditions of use in a reasonable manner and will not
base this determination upon hypotheticals or conjecture. The
identification of ``reasonably foreseen'' conditions of use will
necessarily be a case by case determination, and will be highly fact-
specific. Sources of facts to support such determinations may include
known activities associated with similar chemicals, knowledge of a
chemical's properties that may allow it to replace a function currently
being performed by non-chemical means, or information on research and
development activities applying a chemical substance to a particular
new use. It is reasonable to foresee a condition of use, for example,
where facts suggest the activity is not

only possible but, over time under proper conditions, probable.
    As EPA gains experience in conducting risk evaluations, it will
likely develop additional scoping principles, consistent with the
discussion in this preamble. EPA has issued Guidance to Assist
Interested Persons in Developing and Submitting Draft Risk Evaluation
Under the Toxic Substances Control Act and section 26(l) requires EPA
to reevaluate guidance every 5 years. This document may be the
appropriate venue for EPA to provide additional transparency regarding
conditions of use included/excluded as a part of scoping as the Agency
becomes better versed in this process.

C. General Provisions

    The general provisions of the final rule outline the purpose,
scope, applicability and enforcement of this rule.

D. Definitions

    TSCA defines a number of key terms necessary for interpretation of
the new law, and the statutory definitions apply to this rule. To
increase clarity and transparency, EPA has included a number of
additional definitions in the rule. In the proposed rule, EPA asked for
comments specifically on whether to codify definitions of terms
including ``best available science,'' ``weight-of-the-scientific
evidence,'' ``sufficiency of information,'' ``unreasonable risk,'' and
``reasonably available information,'' among others. EPA identified the
sources of possible definitions, and in some instances provided
extensive discussion of its current interpretation of the terms. EPA
also encouraged commenters to suggest alternative definitions the
Agency should consider for codification in this rule.
    EPA received a number of comments on this subject; in general, many
comments acknowledged that there are numerous ways these phrases can be
defined and ultimately implemented. Many also acknowledged that the
science is changing and the Agency must maintain flexibility to
implement advancing and novel science. Some commenters agreed with
EPA's proposed conclusion that not defining the terms allows for
flexibility to change as the science changes and that strict
definitions may impede TSCA implementation. A number of comments
discussed the legislative history behind these terms, specifically the
fact that previous versions of the statute did include some of these
definitions and that they were removed in the final version. Other
commenters argued that since these terms are not defined in the statute
and there is no requirement in the statute to define them by rule,
there was no Congressional intent to codify definition of these terms
in this rule. Additionally, it was reasoned that any codified
definitions would apply not only to TSCA section 6 actions and rules,
but also to TSCA sections 4 and 5, and potentially other applications
outside of TSCA. They argued this makes it much more difficult to
develop and implement universally appropriate definitions.
    A significant number of commenters did encourage EPA to define, or
at the very least, to provide additional principles and concepts that
will be applied to implement these terms, arguing that this will add
transparency and better articulate how EPA will implement the
scientific criteria of the statute. Some commenters stated that the
definitions of these terms have not changed with changing science, only
the data sets used to inform the definitions. Other commenters, who
agreed these terms do have a number of different meanings believed it
was therefore more important to define them in this rule so the public
knew which definition would be applied. Commenters also stated these
terms are the ``cornerstones'' of risk evaluations under TSCA, and
definitions were necessary to alleviate potential confusion in
implementation of these requirements. Many commenters who believed it
is necessary for EPA to define these terms did include proposed
definitions and/or descriptions.
    EPA has chosen to only define terms in this final rule that appear
in the statute, including best available science, reasonably available
information, and weight of the scientific evidence, among others. EPA
agrees with many of the public comments that the definitions of these
terms in the final rule will instill confidence, increase transparency,
and provide the public with assurance that EPA will adhere to the
requirements of the statute. Based on review of the public comments
received, EPA has also revised the proposed definitions to increase
their clarity, while also adding additional discussion in the preamble.
    EPA will first discuss definitions included in the regulation (in
the order they appear in the regulation), and then will discuss
additional terms that have not been codified, but are important
components of the risk evaluation process.
    1. Aggregate exposure. TSCA requires EPA, as a part of the risk
evaluation, to document whether the Agency has considered aggregate
exposure, and the basis for that decision. 15 U.S.C. 2605(b)(4)(F)(ii).
This term is not statutorily defined; however, EPA has defined
aggregate exposure to be 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.4). This is consistent with the proposed
rule and consistent with agency policy.
    2. Best available science. Section 26(h) of amended TSCA requires
that ``in carrying out sections 4, 5, and 6, to the extent that the
Administrator makes a decision based on science, the Administrator
shall use scientific information, technical procedures, measures,
methods, protocols, methodologies, or models, employed in a manner
consistent with the best available science.'' As stated, many
commenters encouraged EPA to codify a definition of the ``best
available science.'' In response to these comments, EPA determined that
`best available science' is an integral component of section 6 risk
evaluations, and has incorporated a definition of `best available
science' into the regulatory text. The first part of the definition
originates from the Safe Drinking Water Act (SDWA) (42 U.S.C. 300f et
seq.) and is also included in the EPA's Information Quality Guidance
(Ref. 5). The SDWA definition was cited by a number of commenters, and
EPA agrees this definition, already in use at the Agency, is
appropriate. The second part of the definition is taken directly from
TSCA section 26(h), which identifies mandatory approaches to fulfilling
the science standards under TSCA. By basing its definition of `best
available science' on these two sources, EPA believes that the Agency
is remaining consistent with the current approach already used Agency-
wide, while also acknowledging the specific standards under TSCA.
    The final rule defines ``best available science'' as science that
is reliable and unbiased. This involves the use of supporting studies
conducted in accordance with sound and objective science practices,
including, when available, peer reviewed science and supporting studies
and data collected by accepted methods or best available methods (if
the reliability of the method and the nature of the decision justifies
use of the data). Additionally, EPA will consider as applicable:--

--The extent to which the scientific information, technical procedures,
measures, methods, protocols, methodologies, or models employed to
generate the information are

reasonable for and consistent with the intended use of the information;
--The extent to which the information is relevant for the
Administrator's use in making a decision about a chemical substance or
mixture;
--The degree of clarity and completeness with which the data,
assumptions, methods, quality assurance, and analyses employed to
generate the information are documented;
--The extent to which the variability and uncertainty in the
information, or in the procedures, measures, methods, protocols,
methodologies, or models, are evaluated and characterized; and;
--The extent of independent verification or peer review of the
information or of the procedures, measures, methods, protocols,
methodologies or models.

    3. Conditions of use as defined in 15 U.S.C. 2602(4), means the
circumstances, as determined by the Administrator, under which a
chemical substance is intended, known, or reasonably foreseen to be
manufactured, processed, distributed in commerce, used, or disposed of.
This definition was not included in the proposed rule, but has been
added for clarity. Additional discussion of conditions of use can be
found in Unit B.
    4. Pathways. 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. 4). This definition is consistent with
EPA's policies and practices, and did not change from the proposed
rule.
    5. Potentially exposed or susceptible subpopulations. TSCA requires
EPA to evaluate risk to ``potentially exposed or susceptible
subpopulation[s]'' identified as relevant to the risk evaluation by the
Administrator, under the conditions of use. 15 U.S.C. 2605(b)(4)(A).
TSCA defines this as ``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 proposed a
definition to clarify how the Agency interprets this provision.
Specifically, EPA proposed to substitute the phrase ``including but is
not limited to'' for the statutory phrase ``such as,'' to clarify that
the statutory list of potential subpopulations is not exclusive. EPA
also proposed to include additional examples of subpopulations that
have been previously considered. In response to comments, the final
rule simply codifies the statutory definition without revision.
    EPA received a number of comments regarding this definition. Some
stated that EPA was correct in expanding and clarifying the definition
in the proposed rule, while others stated that EPA should use the
statutory definition. Many comments that supported the proposed
definition also identified other subpopulations that EPA should
include. EPA's view of the interpretation of the statutory definition
has not changed since proposal--EPA interprets the statutory definition
broadly and believes it does not prevent EPA from including any
subpopulation that may be at greater risk due to greater susceptibility
or exposure, or from identifying additional subpopulations other than
those listed in the statute, where warranted. The definition in the
final rule uses the statutory definition because, due to EPA's broad
interpretation, EPA does not think that it limits any consideration of
a particular subpopulation. Also, regarding EPA's proposed inclusion of
more examples than those provided by the statute (e.g., life-stage,
age, gender, geography), and in reading public comments, which listed
numerous other important subpopulations EPA should consider, it was
clear that it would be difficult for the Agency to list all the
potential subpopulations that the Agency might have reason to include
in a risk evaluation. Codification of the statutory definition does not
limit the subpopulations that may be evaluated and ensures there is no
misconception that a partial list was intended as a deliberate
exclusion of other subpopulations.
    6. Reasonably available information. 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 defining ``reasonably
available information'' to mean information that EPA possesses, or can
reasonably obtain and synthesize for use in risk evaluations,
considering the deadlines for completing the evaluation. However, there
is a preference for reasonably available information that is consistent
with the required quality standards. Information that meets the terms
of the preceding sentence is reasonably available information whether
or not it is claimed as confidential business information. This
definition is slightly revised from the proposed definition.
    First, EPA deleted the word ``existing'' to address concerns that
this would prevent the Agency from considering (or requiring) data
generated in response to EPA data gathering, including testing,
authorities. Several commenters encouraged EPA to take full advantage
of its new information gathering authorities and not limit the basis of
its decisions to ``existing'' information. EPA agrees that it makes
sense to view information that can be obtained through testing as
``reasonably available'' in some instances--especially information that
can be obtained through short-term testing, where it can be obtained
within the relevant statutory deadlines and the information would be of
sufficient value to merit the testing. As discussed in a related
rulemaking on prioritization under TSCA, EPA will seek to generally
ensure that sufficient information to complete a risk evaluation exists
and is available to the Agency prior to initiating the evaluation. The
proposed definition was drafted to reflect that intention. However, EPA
also recognizes that there may be circumstances where additional
information may need to be developed within the time frames of the risk
evaluation process. This may include information developed through the
use of novel and advancing chemical assessment procedures, measures,
methods, protocols, methodologies, or models (e.g., high-throughput
chemical assessment techniques). While EPA disagrees that its original
definition would have precluded the generation of additional data, to
avoid any confusion, EPA has modified the definition to clarify the
point. Note that EPA will, as appropriate, also require longer-term
testing, and at times will need to do so to address data gaps. However,
EPA does not think information that could be generated through such
testing should be viewed as ``reasonably available''. EPA will tailor
its information gathering efforts as appropriate.
    Second, EPA added a statement regarding CBI to clarify to the
public that EPA does consider CBI under section 14 of TSCA to be
``reasonably available,'' and will utilize it in risk evaluations where
relevant.
    7. Routes. The final rule defines routes of exposure to mean the
particular manner which a chemical substance may contact the body,
including absorption via ingestion, inhalation, or dermally (Ref. 4).
This definition is consistent with EPA's policies and practices and
with the proposed definition.

    8. Sentinel exposure. The final rule defines sentinel exposure to
mean the exposure to a single chemical substance that represents the
plausible upper bound of exposure relative to all other exposures
within a broad category of similar or related exposures. As mentioned
in the proposed rule, this term previously had not been defined by the
Agency. In light of the comments received, many of which requested
revisions to the proposed definition, EPA believes it most appropriate
to revise the definition in the proposed rule. The majority of comments
explained that the concept of sentinel exposures is narrower than the
definition EPA had proposed (``the exposure of greatest significance,
which may be the plausible maximum exposure''); rather, as one comment
explained, sentinel exposures are employed to represent broad
categories of use so that the assessor does not have to go into each
specific subcategory of use. While sentinel exposures do represent
upper-bound exposures--which is part of what EPA proposed--it is the
upper bound within those broad use categories. Under this approach,
because the exposures are expected to be much greater than other
sources or pathways, if the margin of exposure is at an acceptable
level, there is no need to specifically evaluate the other individual
exposure pathways in the category. A number of commenters also
suggested that EPA adopt the approach to `sentinel exposure' used by
the European Union's (EU) European Chemicals Agency (ECHA)
Registration, Evaluation, Authorization, and Restriction of Chemicals
(REACH) program and Health Canada (Ref. 6 and 7). The final definition,
although not the same as the one used by ECHA and Health Canada, more
closely tracks their approach. Specifically, the definition seeks to
address situations including but not limited to: (1) The same chemical
substance is added to a number of related products, and EPA is
evaluating exposure to the chemical substance in these related products
under the same exposure scenario (e.g., adults who could use these
products for the same task). If EPA identifies and evaluates the
product associated with the upper bound of exposure from use of these
products, then EPA could reach risk conclusions for the chemical
substance in the entire category of these products, because the range
of potential exposures is no greater than the magnitude of the exposure
to the chemical substance in the upper-bound product. (2) A number of
different workers are exposed to the same chemical substance. If EPA
identifies or evaluates the worker whose exposure represents the upper
bound of exposure, EPA would have confidence that the other workers
exposed would be less exposed than the worker with the upper bound or
``sentinel'' exposure.
    In the proposed rule, EPA used the phrase ``maximum exposure'' in
defining sentinel exposure. This phrase has been changed to ``upper
bound of exposure'' in the final rule. This change was a result of
public comment that suggested that the term ``maximum'' could indicate
that EPA intended to use only the 99.99th percentile exposure. This was
not EPA's intent, and so EPA has substituted the phrase ``upper-bound
of exposure,'' which is consistent with EPA's existing practice, and
allows EPA the flexibility to consider the available data and its
quality in determining the appropriate exposure scenario (e.g.,
sentinel exposure scenarios).
    9. Uncertainty and variability. 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 proposed
definitions for both ``variability'' and ``uncertainty'' based on
existing Agency guidance (Framework for Human Health Risk Assessment).
The final rule adopts the proposed definition of ``uncertainty'' with
minor modification. EPA added the phrase ``the real world'' to exactly
reflect the definition in Agency guidance. In the final rule,
uncertainty means the imperfect knowledge of the real world or lack of
precise knowledge of the real world either for specific values of
interest or in the description of the system (Ref. 8). The final rule
adopts the proposed definition of ``variability'' without modification.
The regulation thus states: ``Variability'' means the inherent natural
variation, diversity, and heterogeneity across time and/or space or
among individuals within a population (Ref. 8). Both definitions are
consistent with EPA's policies and practices.
    10. Weight of the scientific evidence. The Agency is required by
the statute to use a weight of scientific evidence approach in a risk
evaluation and the Agency is codifying a definition of this term in
this final rule. In responding to public comment, EPA notes that
inclusion of the definition will provide the much requested
transparency to the public regarding the processes for how the Agency
reviews scientific information used in risk evaluations without
stifling scientific advances. In the preamble to the proposed rule, EPA
provided an extensive discussion of how the weight of the scientific
evidence is applied by EPA and the National Toxicology Program of the
National Institutes of Environmental Health. This discussion formed
part of the basis for the definition EPA is promulgating in this final
rule.
    The application of weight of the scientific evidence has generated
much discussion in the scientific community, and EPA agrees with the
National Academies who stated ``because scientific evidence use in
weight of the scientific evidence (WoSE) evaluations varies greatly
among chemical and other hazardous agents in type, quantity and
quality, it is not possible to describe the WoSE evaluation in other
than relative general terms'' (Ref. 9). Application of weight of the
scientific evidence analysis is an integrative and interpretive
process. It is more than a simply tallying of the number of positive
and negative studies. It also is applicable to both human health and
ecological risk evaluations.
    There are certain principles of weight of the scientific evidence
that are universal, including foundational considerations, such as
objectivity and transparency, and the general process. This process
starts with assembling the relevant information, evaluating the
information for quality and relevance, and synthesizing and integrating
the different lines of evidence to support conclusions (Ref. 10). Given
these overarching and inclusive principles, EPA does not think that
providing a general definition restricts flexibility or scientific
advancement. For the purposes of this rule the definition EPA is
adopting states: ``Weight of the scientific evidence means a systematic
review method, applied in a manner suited to the nature of the evidence
or decision, that uses a pre-established protocol to comprehensively,
objectively, transparently, and consistently identify and evaluate each
stream of evidence, including strengths, limitations, and relevance of
each study and to integrate evidence as necessary and appropriate based
upon strengths, limitations, and relevance.'' This definition was
suggested by a few public commenters, it is consistent with practices
under TSCA before it was amended, and was generally outlined in the
lengthy discussion in the proposal. The bulk of the definition, aside
from the phrase ``applied manner suited to the nature of the evidence
or decision'' clarification, is taken directly from TSCA's legislative
history. See Congressional Record at S3519, June 7, 2016. The
additional phrase was added to be consistent with the concept (also
discussed in the proposal) that the components of its risk evaluations
will

be ``fit-for-purpose.'' As explained in the proposed rule at 82 FR
7566, all conditions of use will not warrant the same level of
evaluation, and EPA expects that it may, in some cases, be able to
reach conclusions without extensive or quantitative evaluations of
risk. The addition of this phrase to the definition is intended to
clarify that different weight of the scientific evidence review methods
may be appropriate for different information, types of evaluations, or
decisions. Specifically, fit-for-purpose means that while EPA will
always apply the principles contained in the definition, the depth or
extent of the analysis will be commensurate with the nature and
significance of the decision.
    11. Systematic Review. EPA requested 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. Commenters
both supported and opposed the inclusion of systematic review in the
rule text. Those opposing the codification of systematic review argued
that EPA should retain flexibility and the ability to change the
process as improved methods for systematic review are developed. Some
commenters did encourage a description of the intended approach in the
preamble, but suggested that EPA reserve the specific process for
guidance. Those in support of codifying a description of systematic
review in the rule text stated that inclusion would increase
transparency and would provide the public with an indication of how the
statutory requirement of weight of the scientific evidence,
requirements of sections 6 and 26, and an integral component of
systematic review, will be applied.
    EPA intends to use the systematic review approach, described in the
proposed rule, but is not codifying a definition in the regulatory
text. To be clear, although EPA asked for comment on the need for
regulatory text for systematic review on hazard identification
specifically, EPA will not limit the use of this approach solely to the
hazard assessment, but will use it throughout the risk evaluation
process. The inclusion of a description of systematic review in the
preamble is the most appropriate approach in light of public comment
and the requirements of the statute. First, systematic review is not
required under the statute, only a weight of the scientific evidence
analysis. The definition the Agency is adopting for ``weight of the
scientific evidence'' uses the phrase ``systematic review,'' which
addresses to some extent the commenters who favored including the
concept in this regulation.
    EPA sees weight of the scientific evidence approach as an
interrelated part of systematic review, and further believes that
integrating systematic review into the TSCA risk evaluations is
critical to meet the statutory requirements of TSCA. Although, as EPA
discusses elsewhere in this preamble, there are universal components of
systematic review that EPA intends to apply in conducting risk
evaluations, this is one area where EPA concluded it would be premature
to codify specific methods and criteria that may change as the Agency
gains more experience conducting TSCA risk evaluations. As requested by
commenters, EPA does believe the addition of discussion of the
systematic review approach the Agency intends on utilizing is necessary
for transparency, and so provides the description herein. Section 26(l)
also requires EPA to develop and revise Agency guidance. The Agency
intends to provide further details on systematic review and weight of
scientific evidence approaches under TSCA in future guidance documents.
    As defined by the Institute of Medicine (Ref. 11) systematic review
``is a scientific investigation that focuses on a specific question and
uses explicit, pre-specified scientific methods to identify, select,
assess, and summarize the findings of similar but separate studies. The
goal of systematic review methods is to ensure that the review is
complete, unbiased, reproducible, and transparent'' (Ref. 11).
    The principles of systematic review have been well developed in the
context of evidence-based medicine (e.g., evaluating efficacy of
medical interventions tested in multiple clinical trials) (Ref. 12) and
are being adapted for use across a more diverse array of systematic
review questions, through the use of a variety of computational tools.
For instance, the National Academies' National Research Council (NRC)
has encouraged EPA to move towards systematic review processes to
enhance the transparency of scientific literature review that support
chemical-specific risk assessments to inform regulatory decision making
(Ref. 13). Key elements of systematic review include:

--A clearly stated set of objectives (defining the question);
--Developing a protocol which describes the specific criteria and
approaches that will be used throughout the process;
--Applying the search strategy criteria in a literature search;
--Selecting the relevant papers using predefined criteria;
--Assessing the quality of the studies using predefined criteria;
--Analyzing and synthesizing the data using the predefined methodology;
--Interpreting the results and presenting a summary of findings (Ref.
14)

    12. Sufficiency of information. EPA did not propose to codify this
phrase, but discussed it in the context of having ``enough''
information to conduct a risk evaluation within the statutory
timeframe. However, EPA also specifically requested comment on whether
to define sufficiency of information. Commenters who opposed codifying
a definition stated that the phrase was ``vague'' and could have a
number of definitions and that the information needs for chemical risk
evaluations can vary significantly, so not one definition would be
appropriate. Commenters who supported codifying a definition of this
phrase stated that, specifically for risk evaluation conducted and
submitted by third parties, knowledge of what constitutes sufficient
information is necessary. Consistent with the proposed rule, the final
rule does not codify this term because EPA agrees that the information
required for chemical risk evaluations can be highly variable, and that
given the case-by-case nature of the hazard and exposure scenarios, it
is difficult to have an overarching definition of ``sufficient
information'' applicable to all evaluations. EPA does not believe that
the definitions offered by the commenters would provide any greater
clarity that would effectively inform third party risk evaluations and
expansion of this concept is more appropriate for the statutorily
required guidance documents.
    13. Unreasonable risk. In the proposed rule, EPA said that the
Agency did not think it was appropriate to define ``unreasonable risk''
because each risk evaluation will be unique. For example, defining
specific risk measures for use in all risk evaluations would be
inappropriate to capture the broad set of health and environmental risk
measures and information that might be relevant to chemical substances.
In the preamble to the proposed rule, EPA did discuss some of the
considerations the Agency will use in making a risk determination. The
public overwhelmingly agreed with the proposed approach. EPA did take
public comment on this approach and the public agreed that a definition
was not appropriate, but appreciated EPA's approach to including
considerations.
    For the final rule. the Agency will be taking the same approach,
and has

identified, a revised list of some of the considerations that the
Agency will use in making a risk determination. This is not intended as
an exhaustive list, but merely identifies some of the considerations
that are likely to be among the most commonly used. However, the list
of considerations has changed slightly in response to public comment.
In the proposed rule preamble a few considerations were too specific
and were not expected to be widely applicable to TSCA risk evaluations.
For example, the proposed rule included the specific mention of margin
of exposure (MOE), which is just one approach for risk
characterization. EPA acknowledges that MOE is just one of several
approaches to risk characterization, and agrees that it does not make
sense to single out this one particular approach. There will be risk
scenarios where one approach may be better than another and, as
commenters correctly pointed out, the science of risk characterization
is still evolving, particularly for non-cancer hazards. The proposed
preamble had also included the consideration of cumulative exposure in
making a risk determination. A number of commenters pointed out, this
is not a requirement under the statute; EPA agrees that this may not be
widely applicable to many TSCA risk assessments, and so EPA has not
included it in the list below. Additionally, commenters correctly
pointed out that EPA did not mention environmental risks in the
proposed definition. Considerations of environmental hazards and
exposures have been added.
    To account for the number of different risk characterization
approaches and for changing science, EPA will not include any specific
definition in this final rule. To make a risk determination, EPA may
weigh a variety of factors in determining unreasonable risk. The
Administrator will consider relevant factors including, but not limited
to: The effects of the chemical substance on health and human exposure
to such substance under the conditions of use (including cancer and
non-cancer risks); the effects of the chemical substance on the
environment and environmental exposure under the conditions of use; the
population exposed (including any susceptible populations), the
severity of hazard (the nature of the hazard, the irreversibility of
hazard), and uncertainties.

E. Timing of Risk Evaluations

    A risk evaluation is initiated upon the final designation of a high
priority substance at the completion of the prioritization process or
through the completed manufacturer request process. A risk evaluation
is complete upon the publication of the final risk evaluation, which
includes the final risk determination for all the conditions of use
identified in the Scope document. As indicated, the statute requires
EPA to complete risk evaluations within three years, with the
possibility of a single six-month extension. This rule adopts these
timeframes without modification or elaboration.

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) chemical substances requested by manufacturers,
when the requests meet the criteria for EPA to conduct an Agency risk
evaluation.
    Public comment requested that EPA be explicit about what
constitutes a chemical substance under TSCA. The statute defines a
chemical substance to mean any organic or inorganic substance of a
particular molecular identity, including: (1) Any combination of such
substances occurring in whole or in part as a result of a chemical
reaction or occurring nature, and (2) and element or uncombined
radical. Chemical substances do not include: (1) Any mixture, (2) any
pesticide (as defined in the Federal Insecticide, Fungicide, and
Rodenticide Act) when manufactured, processed, or distributed in
commerce for use as a pesticide, (3) tobacco or any tobacco product,
(4) any source material, special nuclear material, or byproduct
material (as such terms are defined in the Atomic Energy Act of 1954
and regulations issued under such Act), (5) any article the sale of
which is subsequent to the tax imposed by section 4181 of the Internal
Revenue Code of 1954 (determined without regard to any exemptions from
such tax provided by section 4182 or 4221 or any other provision of
such Code), and (6) any food, food additive, drug, cosmetic, or device
(as such terms are defined in section 201 of the Federal Food, Drug,
and Cosmetic Act) when manufactured, processed, or distributed in
commerce for use as a food, food additive, drug, cosmetic, or device.
15 U.S.C. 2602(2)(B). The list constitutes what is commonly referred to
as ``non-TSCA uses.'' It may be appropriate for EPA to consider
potential risk from non-TSCA uses (as identified above) in evaluating
whether a chemical substance presents an unreasonable risk, although
these uses would not be within the scope of the risk evaluation. EPA
would explain the basis for such consideration in any risk evaluation.
EPA may not in a risk management rule under section 6(a) regulate non-
TSCA uses. TSCA Sec.  6(a) generally provides that if EPA determines
that the manufacture, processing, distribution in commerce, use, or
disposal of a chemical substance or mixture, or that any combination of
such activities, presents an unreasonable risk of injury to health or
the environment, the Agency must apply certain regulatory requirements
to the extent necessary so that the chemical substance or mixture no
longer presents such risk. The potential risks of non-TSCA uses may
help inform the Agency's risk determination for the exposures from uses
that are covered under TSCA (e.g., as background exposures that would
be accounted for, should EPA decide to evaluate aggregate exposures).

G. Process and Criteria for Manufacturer Requested Risk Evaluations.

    TSCA allows a manufacturer or group of manufacturers to request
that the Agency conduct a risk evaluation of a chemical substance (or
group of substances) that they manufacture. The statute further directs
EPA to establish the ``form . . . manner and . . . criteria'' for such
requests as part of this rule.
    1. Scope of request. In the proposed rule, EPA required the
manufacturers submitting the request to include all information
necessary to conduct a risk evaluation on all conditions of use. EPA
received numerous public comments on this provision. EPA did receive
comments that supported the proposed approach, indicating that the
approach was consistent with EPA's own process for evaluating high
priority chemicals, and because the chemicals evaluated as the result
of a manufacturer request will have not gone through the Prioritization
process, where the bulk of information may be gathered, it was
appropriate to have manufacturers submit all information necessary to
conduct a risk evaluation for all conditions of use. Those opposed to
the proposed approach stated that manufacturers are not always privy to
every downstream use, and therefore would find it very difficult to
obtain all the required information. Commenters also expressed concern
that the bar set in the proposed rule overall was too high and

would make it extremely difficult for manufacturers to submit a
compliant request, and that the extensive requirements EPA had proposed
could create a disincentive to submit requests for risk evaluation.
    EPA agrees with many of these concerns in opposition to the
proposed approach. EPA believes that Congress intended for EPA to
establish a process under which the 25%-50% target would most likely be
met. The law instructs EPA to ``ensure'' that that target is met.
Section 6(b)(4)(E)(i). While this is conditioned on EPA's receipt of a
sufficient number of compliant requests, EPA believes it signals an
intent that the criteria for requests make it reasonably likely that
the target will be met. Legislative history supports this reading. See
S3516 (June 7, 2016) (``The Administrator should set up a system to
ensure that those percentages are met and not exceeded in each fiscal
year.'')
    Upon consideration of these comments, among others, EPA is
modifying its proposal in several ways. First, the final rule allows
manufacturers to submit requests for risk evaluation on only the
conditions of use of the chemical substances that are of interest to
the manufacturer.
    Although manufacturers may request that EPA conduct a risk
evaluation based on a subset of the conditions of use, EPA intends to
conduct the risk evaluation in the same manner as any other risk
evaluation conducted under section 6(b)(4)(A). This is clear from
subsections (A) and (C), and from section 6(b)(4)(E)(ii), which
expressly directs that the Administrator shall not expedite or
otherwise provide special treatment to manufacturer-requested risk
evaluations. As such, EPA intends to conduct a full risk evaluation
that encompasses both the conditions of use that formed the basis for
the manufacturer request, and any additional conditions of use that EPA
identifies, just as EPA would if EPA had determined the chemical to be
high priority. However, rather than require the manufacturer to
identify any additional conditions of use that EPA will evaluate, EPA
will determine the additional conditions of use during the process of
determining whether to grant or deny the manufacturer request. From
receipt of a compliant request to initiation of a risk evaluation EPA
anticipates 195 days. This includes: (1) Public notification of request
within 15 days of receipt; (2) Within 60 days after receipt of the
request, EPA will publish the request in the Federal Register; (3) EPA
will open a docket to facilitate a no less than 45-day public comment
period; (4) Within 60 days of the end of the comment period EPA will
issue the decision to grant or deny the request; (5) Upon a decision to
grant a request, the requester has 30 days to withdraw the request or
EPA will move to initiate the risk evaluation.
    Upon receipt of a request, EPA will evaluate whether the
circumstances of manufacture, processing, distribution in commerce,
use, and/or disposal identified by the submitter constitute conditions
of use that warrant risk evaluation and whether additional conditions
of use need to be included in the risk evaluation. EPA will apply the
same criteria in the same manner outlined earlier in this preamble in
making these evaluations.
    EPA must complete the full risk evaluation that encompasses both
the conditions of use that formed the basis for the manufacturer
request, and any additional conditions of use that the Administrator
determines under section 15 U.S.C. 2605(b)(4)(A), within the statutory
three-year deadline. However, as discussed elsewhere in this preamble,
EPA may make an early risk determination on any condition of use
included in the Agency's scope, after peer review of the risk
evaluation for that condition of use. Thus, since manufacturers are
required to submit all of the information necessary to complete risk
evaluation for the identified conditions of use, EPA expects these
conditions of use may be good candidates for an early determination.
    2. Information that must be submitted as part of request.
Consistent with the proposal, a request must include the chemical
identity--all known names, CAS number, and molecular structure.
Manufacturers may also submit requests for categories of chemical
substances, and such requests must include an explanation of why the
category is appropriate under 15 U.S.C. 2625(c). EPA will grant such
request only upon determining that the requested category is
appropriate for risk evaluation. As described above, manufacturers may
now request a risk evaluation based on a subset of conditions of use.
The manufacturer's request must include all of the information
necessary for EPA to conduct the evaluation for the requested
conditions of use, consistent with the requirements in sections 15
U.S.C. 2605(b)(4)(A), and 15 U.S.C. 2625(h). This includes all of the
necessary information, as relevant to the requested conditions of use,
on the chemical substance's hazard and exposure potential; the chemical
substance's persistence and bioaccumulation; any relevant potentially
exposed or susceptible subpopulation; whether there is any storage of
the chemical substance near significant sources of drinking water,
including the storage facility location and nearby drinking source; the
chemical substance's production volume or significant changes in
production volume; and any other information relevant to the risks
potentially presented by the chemical substance. The requesting
manufacturer does not need to supply a copy of the information if it is
publicly available, but must list all references. These are the same
requirements EPA listed in the proposed rule; however, the scope of the
request may be narrower, specifically regarding the conditions of use
requested. Some comments argued that it would be exceedingly difficult
to obtain information for uses that the requesting manufacturer may
have no knowledge of. EPA agrees with that, and that is a large part of
the motivation behind EPA's decision to allow manufacturers to request
risk evaluations on limited conditions of use. However, for those
conditions of use requested, the manufacturer must provide all the
information EPA needs for risk evaluation.
    Any information submitted by a manufacturer must be consistent with
the scientific standards in 15 U.S.C. 2625(h). Although the judgement
of consistency is ultimately EPA's, holding the requester to the
statutory standard helps to ensure that if EPA grants the request, the
Agency can effectively utilize the information provided. Additionally,
any information submitted that is claimed as CBI must be accompanied by
a redacted version of the information, including as necessary an
accession number and a structurally descriptive generic name.
Instructions for submitting CBI are also included in this rule.
Consistent with EPA's general interpretation of section 14, the rule
requires upfront substantiation of non-exempt CBI claims.
    The final rule also includes a number of other revisions to the
information that must be submitted for the request to be considered. In
the proposed rule, EPA required manufacturers to submit in the request
any risk assessment or evaluation that they might possess. This was
added to the proposed rule to provide the Agency with additional
information, specifically, as it relates to the hazard assessment. The
Agency's intent was to use this as purely another source of
information, not base any decision solely on the information in this
document. Commenters argued that these risk assessments or evaluations
may have been conducted under a different statute or for a particular
purpose, and therefore may not be

useful or appropriate under TSCA. Additionally, commenters stated that
a risk evaluation may have been conducted in response to litigation and
therefore would be protected under attorney client privilege. In
response to public comments, EPA is removing the requirement that the
manufacturer must commit to providing EPA existing risk assessments on
the chemical. EPA believes that all relevant risk assessments would be
required to be provided pursuant to TSCA section 8(e), and/or would be
submitted in response to the regulatory provision that requires that
the requesters provide any information relevant to the potential risks
of the chemical substance under the circumstances identified in the
request.
    Many commenters also requested that EPA rephrase the certification
statement. Commenters stated that the content of the certification was
overly aggressive and unnecessary given the enforcement provision at
the beginning of the regulation and the enforcement that applies to all
of TSCA.
    3. Process for evaluating requests. Upon receipt of the request,
EPA will verify that the request appears to be valid, i.e., that
information has been submitted that is consistent with the regulatory
requirements. Within 15 business days of receiving a facially valid
request, EPA will publish a public notice of the receipt, which will
include the manufacturer request. This notice is intended to give the
public early notice of the chemical substance that may be under
evaluation from a manufacturer request. Due to the 15 day turn around
on this public notice this will not be a Federal Register Notice, but
an announcement on the Agency's Web site and/or an email announcement.
Between receipt of the request and the subsequent end of public comment
period (discussed in this next part), EPA will work to identify any
additional conditions of use, if any, of the chemical requested. Within
60 days from receipt, EPA will submit for publication an announcement
of the receipt of the request in the Federal Register, open a docket
for the request, make available the information that has been submitted
(taking into account any valid CBI claims), and provide no less than a
45-day comment period. This notice will include the manufacturer
request and EPA's proposed determinations as to whether the activities
identified in the request are conditions of use that warrant risk
evaluation, and whether there are additional conditions of use that
need to be included in the risk evaluation. This public comment period
will allow the public to comment on EPA's proposed determinations and
to identify and/or submit any reasonably available information
regarding hazard, exposure, potentially exposed populations and
subpopulations, and conditions of use that may help inform a risk
evaluation. The requesting manufacturer may also submit any additional
material during this time.
    Chemical substances that EPA has prioritized through the
prioritization process (the subject of separate rulemaking (EPA-HQ-
OPPT-2016-0636)), are subject to two separate public comment periods
prior to the completion of the prioritization process. These comment
periods are designed to ensure that EPA has the necessary information
to evaluate the chemical substances, including, in particular,
information on the relevant conditions of use. EPA is adopting the
similar structure described here for manufacturer requests, under which
EPA will solicit input from the public prior to the decision on whether
to grant the request, as part of the method by which EPA will identify
and gather information on the additional conditions of use to be
addressed in the final risk evaluation. Since manufacturers are
required to submit all the information necessary to complete risk
evaluation on the identified conditions of use, EPA generally expects
that the submitted information would include reasonably complete
toxicity information on the chemical, even though it would likely not
include exposure information relevant to the other conditions of use.
While this pre-risk evaluation process for manufacturer request differs
from the process of high-priority substances and compresses the period
in which EPA will identify conditions of use and supporting
information, EPA believes that some differences are necessary in order
to effectuate Congress' intent to create a workable process for
manufacturer requests that is reasonably likely to hit the numerical
target in the statute. Through this mechanism, EPA expects that in many
cases, the available information will be comparable to what EPA will
identify or generate through the measures identified in the
prioritization framework rule. During the public comment period
associated with each manufacturer request, EPA encourages public
commenters to identify additional information to inform a risk
evaluation that was not in the manufacturer request, including any
additional conditions of use.
    At any time prior to the end of the comment period, the
manufacturer may supplement the original request with new information
they receive or obtain. 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 risk evaluation for the requested conditions
of use.
    Within 60 days 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. If EPA
determines that the request is compliant (i.e., that the activities for
which risk evaluation is requested constitute ``conditions of use'' as
EPA interprets the term, and are conditions of use that EPA concludes
warrant inclusion in the scope of a risk evaluation for the chemical,
and that EPA has the required information necessary for conducting a
risk evaluation on the condition(s) of use requested), EPA will grant
the request. Otherwise, EPA will deny the request. Requesters may
resubmit any denied request. Within 30 days of the notice that EPA will
grant the request, the requestor may withdraw the request for any other
reason after the Agency has notified the requester of the decision to
grant or deny. For EPA to proceed with a risk evaluation on the
chemical requested, it would have to go through the Prioritization
process. The process for conducting the risk evaluation will follow the
regulatory requirements applicable to high-priority chemical risk
evaluations and will not be expedited or otherwise afforded special
treatment. EPA will initiate the risk evaluation consistent with TSCA
section 6(b)(4)(E)(i) upon payment of required fees requirements as
established in the Fees Rule. EPA is not addressing in this rulemaking
the fee amount for manufacturer requested evaluations. The fee amount
will be addressed in a separate rulemaking process.
    Consistent with TSCA section 6(b)(4)(E)(iii), EPA will give
preference to 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
preference, EPA will give further preference to requests in the order
in which a request is received. This last

provision regarding preference is a change from the proposed rule,
where EPA indicated that preference would be given to chemicals where
EPA determined that there were relatively high estimates of hazard and/
or exposure for the chemical substance. EPA received a number of
comments arguing that this was not an appropriate way to order
chemicals to be evaluated. First, comments asked for a definition of
``high estimates of hazard or exposure.'' Other commenters suggested
that manufacturers may submit a request for a low hazard or exposure
chemical to get the EPA determination of no unreasonable risk. There
were also a few comments that stated that the proposed preference
scheme was appropriate in addressing the worst chemicals first. While
EPA agrees that this is the best way to approach the identification of
high priority substances, EPA does not believe this is necessarily the
best approach for selecting among manufacturer-requested evaluations.
EPA believes, on reflection, that Congress intentionally established
the process for industry requests, to operate outside of the
prioritization process, under which lower risk chemicals might be
identified for risk evaluation. Therefore, EPA has dropped this
proposed preference. EPA also acknowledges it is possible that
manufacturers could request an evaluation seeking to get an Agency
determination of no unreasonable risk.

H. Interagency Collaboration

    In the proposed rule, EPA committed to ensuring there will be
interagency engagement and dialogue throughout its risk evaluation
process; however, EPA chose not limit the potential interagency
collaboration by proposing to codify any particular process. EPA
requested specific public comment on whether codifying this
collaboration at a specific point regulation was appropriate.
Overwhelmingly, commenters were supportive of collaboration with other
agencies, and some comments encouraged additional collaboration with
state and local agencies, global partners, and tribes. There were mixed
comments regarding the codification of interagency collaboration at a
particular point in the risk evaluation process. Those in support of
the collaboration stated that other agencies, such as the Occupational
Safety and Health Administration (OSHA) and the National Institute of
Occupational Safety and Health (NIOSH), may have additional information
on worker exposure that will undoubtedly be useful for EPA in
conducting the risk evaluation. Those opposing the codification argued
that this would be overly bureaucratic and a waste of resources, as not
all agencies would have an interest/information on every chemical so
there would not always be the necessity to consult with them.
    EPA has codified collaboration to give the public confidence that
EPA will work with other agencies to gain appropriate information on
chemical substances. As stated a number of times in this preamble, EPA
is committed to transparency and communication with the public.
Codification of interagency collaboration is just one more example of
this commitment. Through this interagency process, EPA expects to gain
additional information into uses and exposure scenarios, with which
other agencies may be more familiar. Additionally, during interagency
meetings (under the Office of Management and Budget process of
reviewing the proposed rule), other federal agencies expressed
significant interest in early and frequent collaboration. Agencies such
as NIOSH and OSHA have resources available and information for
assessing exposure to workers that EPA may not have. Communication with
the Small Business Administration (SBA) Office of Advocacy was
requested by a number of commenters. Collaboration with Consumer
Product Safety Commission (CPSC), which some commenters argued will be
necessary, was requested as EPA evaluates chemicals commonly found in
consumer products. There are a number of other agencies that have
information and expertise that will undoubtedly be useful to the EPA,
and codified collaboration, along with mechanisms already in place,
further guarantees that this information will be utilized.
    By mandating consultation at any particular stage, EPA does not
intend to imply that collaboration with agencies will solely occur at
this step of the process, but including this collaboration upon
initiation gives other agencies sufficient time to work with the EPA to
identify any information that will be useful for EPA risk evaluation
(e.g., existing regulations or mission critical uses) of the chemical
substance. EPA anticipates that this collaboration would include
agencies that may also regulate the chemical substance or the
environment in which the chemical substance may be present, as well as
agencies that may have critical operations that require the chemical
being evaluated, or may otherwise be affected by regulation of the
chemical substance. EPA will also consult with the SBA Office of
Advocacy and other federal agencies, as appropriate, to help facilitate
outreach to the small business sector.
    This provision also is not intended to suggest that EPA will not
collaborate with federal agencies prior to the initiation of the risk
evaluation. EPA has a number of existing mechanisms already in place to
facilitate collaboration between EPA's federal partners and will
continue to utilize them. Collaboration with other agencies is an
important step in identifying chemicals prior to prioritization, as
well as during the risk management phase, if a chemical use is
determined to present an unreasonable risk.
    As requested in the comments, EPA also plans to engage with state
and local agencies where they may have information to inform risk
evaluations. Similarly, EPA looks to increase collaboration with
tribes, as they can be impacted by chemical substances differently due
to unique traditional activities and lifestyles, as discussed in
comments.

H. Risk Evaluation Requirements

    1. Considerations. This subpart identifies and discusses what EPA
will consider in conducting a risk evaluation. The first subpart
identifies the necessary components of the risk evaluation process--a
scope, which will include a Conceptual Model and Analysis Plan, a
hazard assessment, an exposure assessment, a risk characterization, and
a risk determination.
    a. Agency guidance. EPA has a number of existing guidance documents
that inform Agency risk assessment. EPA has been using risk assessments
as a tool 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 on EPA's Web site (Ref. 15). Additionally, on EPA's Web site
is a compendium of guidance, databases and models used for assessing
pesticide risks (Ref. 16) and information about available predictive
models and tools for assessing chemicals under TSCA (Ref. 17). Each of
these Web sites identify and link to a number of written guidance
documents, tools and models.
    In the proposed rule, EPA made it clear that the Agency would be
taking

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 did not propose to mandate
the use of any specific guidance, method or model, to ensure that there
is flexibility. EPA asked for comments about this approach.
    The majority of the commenters did not think the Agency should
mandate the use of or otherwise codify a list of guidance documents.
Many public comments mentioned that many of the guidance documents were
potentially outdated and were in need of updates. These commenters
asserted that codifying these outdated documents would not be
appropriate, nor accurately indicate to the public how risk evaluations
will be conducted. Additionally, many commenters pointed out the
provision in section 26(l) of TSCA that requires EPA to develop and to
regularly review and update, the necessary policies, procedures, and
guidance. This cuts against mandating use of particular guidance
documents in regulation. Other commenters expressed concern that
existing guidance did not take into account new science requirements in
TSCA. By contrast, some expressed the view that the list should be
codified, as it would result in added transparency to the process.
    EPA is not codifying a list of guidance (with the exception of the
Metals Framework as mandated by TSCA), but states in the regulation
that guidance may be used if it constitutes the best available science,
and consistent with the weight of the scientific evidence. This
approach is consistent with the proposed rule, and in line with the
majority of the comments received on this subject. 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. EPA added a new clause regarding the use
of best available science and weight of the scientific evidence to the
regulation; this addition of the clause regarding the use of best
available science and weight of the scientific evidence was done to
ensure that while the documents may have been developed under another
statute, EPA will take care to ensure their use would be compliant with
the various requirements of section 26 of TSCA. While EPA does think
many of the current guidance documents can be utilized effectively
under the statute, the Agency agrees with many of the comments that it
will be necessary to modify some documents to further adhere to the
amendments in the statute, as well as to reflect changing science and
technology. Additionally, section 26(l) requires the development of any
policies, procedures, and guidance that may be necessary to carry out
the amendments of the law, and to routinely review and revise them as
necessary to reflect scientific developments. Codifying documents that
may be changed, while not codifying others that have yet to be
developed, could potentially lead to long processes to change the rule
language.
    The scope of each risk evaluation will identify those guidance
documents that the Agency expects to utilize to inform the risk
evaluation. EPA will use the guidance only to the degree that it
represents the best available science appropriate for the particular
risk evaluation. EPA recognizes that some guidance may be outdated and
may rely on defaults where no data exists currently to replace those
defaults.
    b. 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 rule most often references ``chemical substances,'' EPA
includes a clear statement in the final regulation that nothing in the
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 evaluate categories of chemical substances.
This is the same provision that EPA included in the proposal, but EPA
has removed the statement regarding the Agency's consideration of
hazards and exposures associated with the category of chemicals, and
the populations likely exposed. EPA believed that this was duplicative,
because EPA is required to treat categories of chemicals in the same
manner as individual chemical substances.
    c. Science requirements. EPA has incorporated into the regulatory
text the statutory requirements regarding best available science and
weight of the scientific evidence. Definitions of those terms have also
been added. While EPA prefers high quality data, where available, EPA
recognizes that data is not always necessary to reach a scientifically
grounded conclusion on the potential risks of a chemical substance,
within the timeframes dictated by the statute.
    As a matter of practice, EPA has been, and will continue to be,
committed to basing its decisions on the best available science and the
weight of the scientific evidence. In response to public comments on
the proposal, EPA has determined to make a number of additions to the
final rule to ensure that the science standards in TSCA are more
explicitly incorporated into the risk evaluation process. Specifically,
EPA has added specific language to the final rule stating that EPA will
evaluate hazard and exposure data in a manner consistent with the
section 26 science standards including documenting the use of the
standards in 15 U.S.C. 2625(h) and the weight of the scientific
evidence in 15 U.S.C. 2625(i). These changes clarify that EPA's risk
evaluations will be consistent with TSCA's new requirements in section
26 related to best available science and weight of the scientific
evidence.
    d. Fit-for-purpose risk evaluations. As described in the proposed
rule and in Unit III.D.10, each risk evaluation will be fit-for-
purpose--that is to say, the level of refinement will vary as necessary
to determine whether the chemical substance presents an unreasonable
risk, given the nature of the evidence, for the conditions of use of a
specific chemical substance. A number of the public comments received
stated their support for this approach, as it conserves the Agency's
resources to focus on the most important components of a given risk
evaluation.
    EPA introduced the idea that risk evaluations would be conducted in
a fit-for-purpose manner in the proposed rule. Specifically, EPA stated
that all conditions of use evaluated will not warrant the same level of
evaluation, and that EPA expects, that in some cases, it may be able to
reach conclusions without extensive or quantitative evaluations of
risk. For example, a lower-volume or less dispersive (those uses that
do not spread as far in the environment, either indoors or outdoors as
compared to a different use) condition of use might require a less
quantitative, data-driven evaluations to credibly characterize the
risks 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 methods approaches.

EPA will continue to utilize this approach and has retained it in the
final rule. The concept of fit-for-purpose risk evaluations is further
explained in the regulation as follows: EPA will refine, as necessary,
its evaluations for one or more conditions of use in any risk
evaluation and when information and analysis are sufficient to make a
risk determination using assumptions, uncertainty factors, and models
or screening methodologies, EPA may decide not to refine its analysis
further. Both of these provisions give EPA the flexibility to conduct
risk evaluations in a manner that best suits the available information
and the decisions that will be made. These are generally consistent
with the proposed text, however some changes have been made, namely the
exclusion of the phrase ``accepted science policies.'' A number of
commenters expressed concern regarding the lack of clarity of this
language. Commenters asked for specific examples of science policies
and some commenters expressed concern that the Agency would confuse
science with regulatory policy, and specifically encouraged separation
between the two, to ensure that EPA's decisions would be science-based.
To address these concerns EPA has deleted the reference to ``science
policies'' from the rule text.
    Many commenters suggested that this fit-for-purpose approach would
be necessary to evaluate chemical substances within the statutory
timeframe, and agreed that this is appropriate because due to the
nature of some uses, some will not necessitate the same level of
evaluation as others. By contrast, some commenters were concerned that
the fit-for-purpose approach is not scientifically sound and can never
be objective. To clarify, EPA will not sacrifice best available science
in implementing this approach. The speed of an evaluation does not
equate to less rigorous science. EPA will always be transparent about
the data and assumptions used.
    e. Timing of a risk determinations. In the proposed rule, EPA
explicitly allowed for the expedited evaluation for a particular
condition of use to, if necessary, 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). A number of commenters
raised concern about the apparent one-sided nature of this provision,
arguing that this appeared to preclude a similar determination that a
chemical substance did not present an unreasonable risk. EPA agrees
that logically such determinations could be appropriate in either case,
and has revised its approach to apply more generally. Accordingly, the
final regulation at 720.41(a)(7) has been revised to clarify that EPA
may make early risk determinations that a chemical substance does or
does not present an unreasonable risk under particular conditions of
use. The final rule also makes clear that any expedited determination
may be issued at any point after the final scope is published. As
discussed previously, all early determinations would be portions of the
final, complete risk evaluation and would therefore be made using the
procedures applicable to TSCA risk evaluations established in this
rule. TSCA is very clear that unreasonable risk determinations cannot
be made until after a risk evaluation that meets the requirements of
section 6(b)(4) is complete. Any risk evaluation for a chemical under
particular conditions of use will therefore be consistent with all
statutory requirements as well as the procedures established in this
regulation. This would also include the requirement that EPA publish a
draft risk evaluation for no less than a 60-day public comment period,
and the regulatory requirement for peer review.
    The final regulation also continues to explicitly state that in any
case where EPA would find it necessary to issue an early risk
determination for a chemical substance under particular conditions of
use of a chemical, the Agency will still complete a risk evaluation on
all conditions of use identified in the final scope, within the
statutory 3-year deadline. In sum, the final rule explicitly recognizes
that EPA may make early risk determinations, to either to manage
unreasonable risks as they are identified, through the issuance of a
regulation under TSCA section 6(a) or to notify the public as soon as
possible of the safety of a chemical substance under a particular
condition of use.
    f. Metals or metal compounds. As required by the statute, 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. 3) or a successor document that addresses metals risk
assessment and is peer- reviewed by the Science Advisory Board. The
final rule, consistent with the proposal, merely reiterates this
statutory mandate.
    2. Information and information sources. For those chemical
substances designated as high priority for risk evaluation, EPA expects
to 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. In
the proposal, EPA had stated that the goal would be to ``only''
initiate the process once most of the information necessary to complete
the evaluation was reasonably available. In the final rule the word
``only'' has been deleted to account for the fact that EPA may use its
regulatory authorities to obtain or require the generation of
additional information even after the risk evaluation has been
initiated.
    For manufacturer requested risk evaluations, EPA acknowledges it
may potentially be difficult to gather all of the necessary information
prior to risk evaluation, as these chemicals will not have gone through
the prioritization process. Nevertheless, EPA generally expects that it
will be feasible to obtain the necessary information to complete a risk
evaluation within the statutory timeframe. As discussed previously, the
final rule requires a manufacturer to submit all of the necessary
hazard information for EPA to complete a risk evaluation on the one or
more conditions of use that have been requested. Although there may be
other hazards associated with other conditions of use that present
different routes of exposure, EPA expects that the majority of the
necessary hazard information will be obtained through the request. EPA
has then allotted 195 days from receipt of request to gather additional
information required to assess both requested uses and any additional
conditions of use EPA has determined warrant evaluation. For both EPA-
and manufacturer-initiated risk evaluations, EPA may also rely on
information developed through the use of novel and advancing chemical
assessment procedures, measures, methods, protocols, methodologies, or
models (e.g., high-throughput chemical assessment techniques).
    For identified data needs, EPA may issue a voluntary call to the
public for relevant information or otherwise engage directly with
stakeholders, followed, as necessary, by exercise of EPA's authorities
under TSCA to require submission or generation of new data.
Accordingly, as appropriate, EPA will exercise its TSCA information
collection, testing, and subpoena authorities, including those under
TSCA sections 4, 8, and 11(c) to obtain the information needed for a
risk evaluation. EPA notes as well that TSCA section 8(e) 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 or
mixture presents a substantial risk of injury to health or the
environment, shall immediately inform the Agency, and EPA may obtain
some information through this route.
    EPA also expects to obtain scientific advice from the Science
Advisory Committee on Chemicals (SACC), which the Agency is required to
develop and convene under TSCA section 26(o).
    When conducting a risk evaluation, EPA will ensure that risk
evaluations are consistent with the scientific standards in section
26(h) and (i), including reliance on the best available science and the
weight of the scientific evidence. EPA will rely on data, models, and
screening methods, as needed. The use of these methods will be balanced
by the quality of the information (consistent with standards in section
26(h) and (i)) and the statutory deadlines for completing a risk
evaluation. In the final rule, EPA will use the scope to focus on the
reasonably available information and science approaches, and reserve
uncertainty considerations specifically for the remainder of the risk
evaluation.
    EPA does not intend to preclude the generation of new scientific
information to inform risk evaluations, however, as mentioned in the
discussion of reasonably available information, the extent to which EPA
will consider any newly generated information in a risk evaluation will
depend on the statutory deadlines.
    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). The
intent to reduce testing on animals was in the proposed text, however
comments suggested the language was not exactly as the statute
intended, and that it should refer to the development of new
information, not all existing information, as it could have been
interpreted. The final rule text has been amended to more closely hew
to the statute.

I. Risk Evaluation Steps

    1. Scope. The first step of a risk evaluation is the development of
the scope. The scope of each risk evaluation will include the following
components. The conditions of use, as determined by the Administrator,
that the EPA plans to consider in the risk evaluation will be included
in the scope. This is amended from the proposed rule to address the
approach to conditions of use as explained in Unit III.B. The EPA will
identify the potentially exposed or susceptible subpopulations EPA
expects to consider, the ecological receptors, and the hazards to human
health and the environment the Agency plans to evaluate will also be
included. From the proposed rule, EPA changed ``ecological
characteristics'' to ``ecological receptors.'' This was done to clarify
that the Agency will be evaluating specifically the impact of the
chemical stressor, and EPA believes that characteristics was too broad,
and receptors more closely hew a chemical risk assessment. The scope
will include a description of the reasonably available information and
the science approaches that the Agency plans to use. In the proposed
rule EPA had included that the reasonably available information would
include ``accepted science policies (e.g., defaults and uncertainty
factors), models, and screening methodologies.'' As already discussed,
a number of commenters expressed their concern with this language and
in response EPA removed this provision. Under the final rule, the scope
will focus on the reasonably available information and science
approaches, and reserve uncertainty considerations specifically for the
remainder of the risk evaluation.
    EPA will 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, hazards,
which will include dose-response, and risk, including associated
uncertainty and variability. The analysis plan will also include a
description of the reasonably available information and science
approaches the EPA plans to use.
    As requested by a number of commenters, the scope will also include
the plan for peer review the Agency expects to consider. This may
include the plan for peer review for those conditions of use that EPA
expects to make early risk determinations on. This plan may also
include the Agency's plan to have any methods or models peer reviewed,
along with the risk evaluation, as well as the EPA's anticipated use of
the SACC or another peer review body or whether the Agency anticipates
a letter peer review or a committee consensus peer review. The Peer
Review Handbook walks through the numerous options the Agency can use,
and the plan will give the public an idea of what the Agency intends to
use for a particular risk evaluation.''
    EPA will publish a notice in the Federal Register, announcing the
availability of the final scope within six months of the initiation of
the risk evaluation. Although not required under the statute, EPA will
publish a draft scope and provide for no less than a 45 calendar day
public comment period during this six-month period. As a number of
commenters pointed out, there was a mistake in the proposed rule--the
length of the commenter period on the draft scope was 30 days in the
preamble, but 45 days in the regulatory text. EPA has corrected this
mistake. 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, the
prioritization process requires two public comment opportunities, and
EPA expects this will reduce the likelihood of significant comments on
the draft scope for those High-priority chemicals.
    EPA has deleted the issue preclusion clause included in the
proposed rule stating that ``any issues related to the scope not raised
in the comments at that time cannot form the basis for an objection or
challenge in a future administrative or judicial hearing'' in response
to a significant number of comments. However, under general principles
of administrative law, commenters are required to identify relevant
available information and raise objections that could be raised during
established comment periods, and courts generally will require
commenters to have done so as a matter of exhaustion of administrative
remedies. EPA has concluded that these principles provide sufficient
assurance that commenters will raise timely objections and provide
timely information and has therefore decided to strike the proposed
regulatory text.
    2. Hazard assessment. In compliance with TSCA section 6(b)(4)(F),
EPA will conduct a hazard assessment on each chemical substance or
category, under the conditions of use as identified in the scope. A
hazard assessment identifies the types of adverse health or
environmental effects or hazards that can be caused by exposure to the
chemical substance in question, and to characterize the quality and
weight of the scientific evidence supporting this identification.
Hazard identification is the process of determining whether exposure to
a chemical stressor can

cause an increase in the incidence of specific adverse health or
environmental effects (e.g., cancer, developmental toxicity). All
information used in this assessment will be reviewed in a manner
consistent with reliance on the best available science and a weight of
the scientific evidence approach.
    As the rule text indicates, EPA will present the hazard
information, as identified in the scope, for the identified exposure
scenarios, and including any identified potentially exposed or
susceptible subpopulation. From the proposed rule, EPA changed the word
``endpoints'' to ``hazards,'' as hazards is more general and inclusive.
    The hazard assessment will identify the types of hazards to human
health and the environment. The information will be reviewed in a
manner consistent with use of the best available science and with the
weight of scientific evidence. This will include the identification,
evaluation, and synthesis of information to describe the potential
health and environmental hazards of the chemical, under the conditions
of use, and all assessment methods will be documented. 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, and
cardiovascular impacts, and neurological impairments. The assessment
may evaluate effects at life stage(s) most appropriate for a receptor
target.
    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.
    Potential information sources that may support the hazard
assessment include but are not limited to: Population based
epidemiological studies that identify risk factors and susceptible
subpopulations; information related to geographic location of
subpopulations; models that represent health effects of relevant
subpopulation; 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, and computational
toxicology, which the final rule makes clear may include high-
throughput assays, genomic response assays, data from structure-
activity relationships, and ecological field data. The hazard
identification will also include an evaluation of the strength,
limitations, and uncertainties associated with the reasonably available
information. The final rule was amended to include uncertainties as
commenters encouraged EPA to further discuss how uncertainties will be
addressed in this process.
    Specifically, for human health hazards, the assessment will
consider all potentially exposed or susceptible subpopulation(s)
identified in the scope. EPA will use an 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
information or methodology consistent with scientific standards.
    An environmental hazard assessment will evaluate the relationship
between the chemical substance and the occurrence of an ecological
response. This assessment may be conducted using reasonably available
information from field or laboratory data, modeling strategies, and
species extrapolations, if needed.
    Changes from the proposed rule include the addition of EPA's
commitment to using the best available science and a weight of the
evidence approach. Some specific details regarding the available
information that may be used in hazard assessments have been moved to
this preamble. The proposal stated that EPA ``may include'' followed by
a list of types of information, and although the phrase ``may include''
provides flexibility, EPA believes that it is more appropriate to not
codify this level of specific detail in the regulation. Many public
comments encouraged transparency in the Agency's risk evaluation
process, but because this rule must cover the process for all risk
evaluations, which by nature will necessitate the consideration of many
types of information sources, EPA believes the better (and ultimately
more accurate) approach is to ensure that it provides full transparency
in the individual risk evaluations.
    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 will include
information on chemical-specific factors, including but not limited to:
Physical-chemical properties and environmental fate and transport
parameters. These considerations were included in the proposed rule;