April 2021
As part ofEPA's evaluation of its policies, guidances, templates, and regulations in the
TSCA New Chemicals program. EPA is seeking to better align the decision-making
process for new chemicals with the requirements of TSCA. As such, EPA has recently
made some changes in implementation of the new chemicals programs and will
continue to evolve its approach for making determinations and managing risks
associated with new chemical notices under TSCA section 5. As a result of these
changes, portions of the 2019 "Working Approach" are no longer reflective of the
Agency's current process and approach. While the Agency considers whether further
program implementation changes may be appropriate, we will continue to be
transparen t about these changes. In terested stakeholders can follow EPA
announcements and/or subscribe to our email list by visiting our website. Further,
companies are encouraged to work with EPA staff if they have any questions regarding
these changes and any potential impacts to their TSCA section 5 notices and/or
exemption submissions.
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December 2019
TSCA New Chemical Determinations
A Working Approach for Making Determinations under TSCA Section 5
I. Introduction
The Toxic Substances Control Act ("TSCA"), as amended in 2016 by the Frank R.
Lautenberg Chemical Safety for the 21st Century Act, requires EPA to make
determinations on new chemical notices received under section 5.
On November 6, 2017, EPA's Office of Pollution Prevention and Toxics (OPPT) released
a document titled "New Chemicals Decision-Making Framework: Working Approach to
Making Determinations under section 5 of TSCA" (Working Approach). EPA solicited
comments on the working approach and other draft documents relating to new chemical
reviews and held a public meeting on December 6, 2017, to discuss and receive input.
The purpose of the Working Approach document was to increase transparency associated
with implementation of the TSCA new chemicals program. Given the significant
amendments to TSCA section 5 in 2016, EPA believes that it is valuable for stakeholders
to have insight into EPA's evolving thinking on the implementation of this important
provision of TSCA.
EPA is now updating the Working Approach document after consideration of comments
received on the November 2017 version and based on additional implementation
experience since that version was made available for comment.
Any action EPA takes on a new chemical submission is governed by application of the
relevant statutory and regulatory requirements to the facts presented in the submission.
This document discusses EPA's working approach to reviewing and acting on
submissions under section 5(a)(1) of TSCA. EPA may choose to depart from this
approach with respect to any specific submission as the Agency deems appropriate. This
working approach does not create new authority, does not limit EPA's discretion in any
way, nor does it bind the public. EPA may at any time revise its working approach based
on learned experiences as EPA implements amended TSCA section 5, as well as based on
any other appropriate circumstances.
As EPA continues to gain experience with new chemicals decision-making under
amended TSCA, the Agency expects to evolve its working approach to making
determinations under section 5 and to update this document as appropriate.
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II. Overview
TSCA requires EPA to review section 5 notices, specifically, a premanufacture notice
(PMN), microbial commercial activity notice (MCAN), or significant new use notice
(SNUN), and make a determination before the new chemical can enter commerce or the
significant new use can commence. TSCA sets forth five possible EPA determinations on
new chemical notices:
• The chemical or significant new use presents an unreasonable risk of injury to
health or the environment1
• Available information is insufficient to allow the Agency to make a reasoned
evaluation of the health and environmental effects associated with the chemical or
significant new use2
• In the absence of sufficient information, the chemical or significant new use may
present an unreasonable risk of injury to health or the environment3
• The chemical is or will be produced in substantial quantities and either enters or
may enter the environment in substantial quantities or there is or may be
significant or substantial exposure to the chemical4; or
• The chemical or significant new use is not likely to present an unreasonable risk
of injury to health or the environment.5
The working approach in this document describes, for the purposes of increasing
transparency into EPA's processes and providing clarity to all parties that interact with
the Section 5 program:
• EPA's general guiding principles and concepts for making determinations on new
chemical notices submitted to EPA under section 5 of TSCA;
• The decision-making logic and the key questions that EPA must address; and
• A discussion of how EPA might apply the working approach to reach one of the
five new chemical determinations allowable under the statute.
III. General Guiding Principles and Concepts
EPA utilizes a risk-based approach to assess whether a new chemical substance, under
the conditions of use (as determined by the Administrator), presents an unreasonable risk
of injury to health or the environment. The assessment culminates in an EPA
determination under TSCA section 5(a)(3). Based on that determination, EPA is required
to take certain additional actions, potentially including risk management actions (e.g.,
restrictions on manufacturing, processing, use, disposal, etc.) to address unreasonable
risks, before a company may commence manufacture or processing of the chemical. This
1 See TSCA § 5(a)(3)(A), 15 U.S.C. § 2604(a)(3)(A).
2 See TSCA § 5(a)(3)(B)(i), 15 U.S.C. § 2604(a)(3)(B)(i).
3 See TSCA § 5(a)(3)(B)(ii)(I), 15 U.S.C. § 2604(a)(3)(B)(ii)(I).
4 See TSCA § 5(a)(3)(B)(ii)(II), 15 U.S.C. § 2604(a)(3)(B)(ii)(II).
5 See TSCA § 5(a)(3)(C), 15 U.S.C. § 2604(a)(3)(C).
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section describes some general guiding principles and important concepts associated with
making determinations under TSCA section 5(a)(3).
A. Overall Policy
EPA's new chemicals program is intended to ensure that new chemicals do not present an
unreasonable risk of injury to health or the environment under the conditions of use.
EPA implements its authority under TSCA in a manner that facilitates timely reviews and
does not impede unduly or create unnecessary economic barriers to technological
innovation in chemical manufacturing.
B. Risk-Based Approach
EPA makes new chemical determinations using a risk-based approach, which takes into
account both hazard and exposure. These determinations must also be made without
consideration of costs or other non-risk factors.6
C. Conditions of Use
In reviewing new chemical notices, TSCA requires EPA to assess the chemical substance
"under the conditions of use," defined in the law 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."7
The identification of conditions of use is a key step in making a determination under
TSCA section 5(a)(3). The concepts of "intended," "known" and "reasonably foreseen"
are described below and discussed further in a subsequent section on EPA's decision-
making logic.
i. Intended Conditions of Use. EPA generally considers the intended conditions of
use to be the circumstances of manufacture, processing, distribution in commerce,
use, or disposal as stated in the section 5 submission. Risk mitigating practices and
controls identified in the submission (e.g., production volume estimates, controls on
releases to air or water, disposal practices, use of engineering controls, and personal
protective equipment (PPE), etc.) are generally considered to be part of the intended
conditions of use.
ii. Known Conditions of Use. Often there are no known conditions of use associated
with a new chemical substance given that the chemical is typically "new" to the U.S.
marketplace.8 However, there may be chemicals that are already being manufactured
in the U.S. pursuant to an exemption under TSCA section 5(h). Such chemicals are
not listed on the TSCA Inventory, and therefore still "new" chemicals subject to the
TSCA section 5 notice requirements. EPA may identify known conditions of use
associated with these chemicals.
6 See TSCA § 5(a)(3), 15 U.S.C. § 2604(a)(3).
7 See TSCA § 3(4), 15 U.S.C. § 2602(4).
8 Because TSCA jurisdiction extends only to activities in the U.S., EPA interprets known
uses as limited to uses within the U.S. However, evidence of use of a chemical outside
the U.S. could result in EPA identifying such a use as a reasonably foreseen condition of
use.
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iii. Reasonably Foreseen Conditions of Use.
Reasonably foreseen conditions of use are future circumstances under which the
Administrator might expect the new chemical substance to be manufactured,
processed, distributed, used, or disposed of. Reasonably foreseen conditions of use
are separate from and in addition to a submitter's intended conditions of use. The
identification of reasonably foreseen conditions of use is necessarily a case-by-case
determination and highly fact-specific, necessitating that EPA apply its professional
judgment, experience, and discretion. The sources EPA uses to identify reasonably
foreseen conditions of use may include, but are not limited to, searches of internal
confidential EPA PMN databases (containing use information on analogue
chemicals), other U.S. government public sources, patent abstracts in the Chemical
Abstract Service STN platform, the National Library of Medicine's Hazardous
Substances Data Bank (HSDB), other information in the Chemical Abstract Service
STN Platform, REACH Dossiers, and technical encyclopedias (e.g., Kirk-Othmer and
Ullmann).
D. Information Sufficiency
Whether there is sufficient information to permit a reasoned evaluation of the health and
environmental effects is a key consideration in identifying which among the five
available determinations under TSCA section 5(a)(3) might be appropriate.
"Sufficient information" does not necessarily mean complete or perfect information. For
example, if EPA has compelling data indicating a chemical poses no hazard, but lacks
exposure data, the Agency may nonetheless have sufficient information to permit a
reasoned evaluation of the health and environmental effects of the PMN substance due to
the lack of hazard.
Additionally, "sufficient information" need not necessarily be data on the actual chemical
substance. As a long-standing practice, where appropriate, EPA often relies on analogue
data to conduct a reasoned evaluation.
"Sufficient" information is not defined in TSCA or EPA's TSCA regulations. Given the
case-by-case nature of the hazard and exposure scenarios, and the variability in what
could be considered "sufficient" information for a particular assessment, EPA does not
believe that a single definition would be appropriate. This is consistent with other
contexts in which EPA explicitly declined to codify a definition of "sufficient"
information.9
9 See Final Rule; Procedures for Chemical Risk Evaluation Under the Amended Toxic
Substances Control Act. EPA-HQ-OPPT-2016-0654-0108, July 20, 2017. Available
online at: https://www.regulations. gov/document?D=EPA-HQ-OPPT-2016-0654-0108.
See also Response to Comments on Proposed Rule; Procedures for Prioritization of
Chemicals for Risk Evaluation under the Toxic Substances Control Act. EPA-HQ-
OPPT-2016-0636, July 20, 2017. Available online at:
https://www.regulations.gov/document?D=EPA-HQ-OPPT-2016-0636-0076
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E. Unreasonable Risk
When a risk is identified, EPA considers a variety of factors in determining whether such
risk presents an unreasonable risk of injury to health or the environment. These factors
include but are not limited to the potential adverse effect (e.g., severity and/or
reversibility) of the substance and/or its degradation products, the nature of the potential
exposures (e.g., duration, magnitude, population, etc.) under the conditions of use, and
workplace practices and exposure controls. As described in the risk evaluation
framework rule10, EPA has not formally defined the term "unreasonable risk." Instead, a
determination of whether or not a risk is unreasonable is made on a case-by-case,
chemical-specific basis.
F. Testing Requirements
Sections 4 and 5 of TSCA provide EPA with authority to require development of new
information to characterize the risk pertaining to a chemical substance submitted under
TSCA section 5(a). Generally, EPA requires additional information when there is
insufficient information to perform a reasoned evaluation of health or environmental
effects. Test data can reduce uncertainty in the risk assessment and provide a basis for the
Agency to modify its risk management approach. Consistent with these authorities, EPA
may, for example, require a submitter to develop and submit test data (e.g., physical-
chemical properties, environmental fate, exposure monitoring or modeling, health or
environmental toxicity) before the chemical can enter the market, or upon a submitter
reaching a certain manufacturing volume threshold. Any requirement for testing by EPA,
consistent with section 4(h), will be structured to reduce and replace vertebrate animal
testing to the extent practicable and scientifically justified. EPA strives to operate within
a tiered testing context, under which the results of lower-tiered testing will be used to
evaluate whether additional higher-tiered tests are necessary.
G. Scientific Standards and Evidence
As required in TSCA section 26, EPA makes decisions under section 5 based on the
weight of the scientific evidence and employs scientific standards consistent with best
available science.
H. Significant New Use Rules (SNURs)
A SNUR is a rule that identifies a potential new use11 of a chemical as a "significant new
use." SNURs require persons who intend to manufacture (defined by statute to include
import) or process a chemical substance for a significant new use to notify EPA at least
90 days before commencing that activity. The required notification, known as a
10 See Unit III(D) of Final Rule; Procedures for Chemical Risk Evaluation Under the
Amended Toxic Substances Control Act. EPA-HQ-OPPT-2016-0654-0108, July 20,
2017. Available online at: https://www.regulations.gov/document?D=EPA-HQ-OPPT-
2016-0654-0108
11 In addition to specific functional uses of a chemical that are new and different from the
intended or known conditions of use, EPA may identify other circumstances of
manufacturing, processing, distribution in commerce, use or disposal (e.g., manufacturing
under a different process, in a different physical form, above a certain concentration, etc.)
as "significant new uses" (SNUs).
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Significant New Use Notice (SNUN), provides EPA with available hazard, exposure and
use information regarding the use of the chemical substance. The SNUN initiates EPA's
evaluation of the notice, in accordance with the requirements of TSCA section 5. EPA
must either (a) conclude that the significant new use is not likely to present an
unreasonable risk under the conditions of use, or (b) take appropriate action under section
5(e) or 5(f). No person may commence manufacture or processing for the use specified
in the SNUN until EPA has conducted a review of the notice, made an appropriate
determination on the notice, and taken such actions as are required by that determination
in accordance with the requirements of TSCA section 5. EPA utilizes SNURs in the new
chemicals program12 in three ways:
i. SNURs that Precede "Not Likely" Determinations. Where EPA identifies
reasonably foreseen conditions of use associated with a new chemical notice, but
lacks sufficient information to perform a reasoned evaluation and/or has identified
potential risks associated with those conditions of use, EPA may consider whether a
SNUR would address those concerns. Specifically, prior to making a determination
under TSCA section 5(a)(3), EPA may consider proposing a SNUR designating those
reasonably foreseen conditions of use as significant new uses.13 Where EPA does not
identify risks associated with the known or intended conditions of use during its
review of a PMN, proposal of a SNUR enables the Agency to make a "not likely to
present an unreasonable risk" determination on the notice while ensuring that any
manufacturing or processing activity outside of the known and intended conditions of
use would first be subject to closer scrutiny by EPA through submission of a SNUN.
In the absence of the SNUR, such a determination by EPA would not be possible.
Although the requirements of a SNUR are not effective until 60 days after publication
of the final rule in the Federal Register, EPA believes that a TSCA section 5(a)(3)
determination (i.e., not likely to present an unreasonable risk) can be made following
issuance of the proposed rule. Based on EPA's experience, a new use is not likely to
commence during the pendency of a proposed SNUR because the publication of a
proposed SNUR on EPA's website serves as the cut-off date for a significant new
use. It is unlikely that manufacturers and processors would commence a prohibited
new use that they would be legally required to cease upon the finalization of the
SNUR. Once a SNUR is final and effective, no person may commence manufacture
or processing for the significant new use without first submitting a SNUN as
described earlier. If EPA did not finalize the proposed SNUR, that decision would
12 In addition to publication of proposed and final SNURs in the Federal Register, EPA
highlights recent SNUR activities on its webpage here: https://www.epa.gov/reviewing-
new-chemicals-under-toxic-substances-control-act-tsca/recent-activities-new-chemicals.
13 TSCA authorizes EPA to issue a SNUR for a chemical substance at any time, including
during review of a section 5 notice for a chemical substance. TSCA section 5(a)(2)
applies to "a chemical substance," without restriction to chemical substances in
commerce. EPA has issued numerous SNURs for substances that have not yet entered
commerce (i.e., for which EPA has not received a Notice of Commencement of
Manufacture or Import under 40 CFR 720.102).
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necessarily be based on information and data provided to the Agency during the
comment period demonstrating that the new uses subject to the proposed SNUR are
not likely to present an unreasonable risk.
ii. SNURs that Follow Section 5(e) Orders. Depending on EPA's determination
under TSCA section 5(a)(3), the Agency may be required to issue an order under
TSCA section 5(e) that imposes certain restrictions or requirements on the submitter
to address unreasonable risks. However, section 5(e) orders apply only to the original
submitter of the notice. TSCA requires that EPA consider promulgating a SNUR
following a 5(e) order.14 EPA often uses its SNUR authority to extend the limitations
in section 5(e) orders to other domestic manufacturers, importers and processors.
This ensures that all domestic manufacturers, importers, and processors are subject to
similar restrictions and reporting requirements
iii. SNURs that Follow "Not Likely" Determinations.
If EPA has determined that the chemical substance under its conditions of use is "not
likely" to present an unreasonable risk, EPA may still issue a SNUR that follows the
determination. Specifically, where EPA has identified other circumstances that -
should they occur in the future, even if not reasonably foreseen - may present risk
concerns, EPA may consider identifying those other circumstances as significant new
uses. This ensures that those circumstances will not occur absent notification to the
Agency and further review before manufacture or processing for the significant new
use is commenced. EPA has a long history of identifying such circumstances as
significant new uses in a SNUR.
IV Decision-Making Logic and Key Questions
In reaching a determination under TSCA section 5(a)(3), there are a number of questions
that EPA considers:
1. What are the intended, known and reasonably foreseen conditions of use?
2. Does EPA have sufficient information to perform a reasoned evaluation? and
3. Can EPA address information deficiencies or risk concerns for reasonably
foreseen conditions of use through the issuance of a SNUR?
As described below, the answers to these questions serve to guide EPA's review of new
chemical notices and inform determinations under TSCA section 5(a)(3).
A. Identification of Conditions of Use
TSCA requires EPA to assess new chemical substances "under the conditions of use."
Conditions of use associated with the chemical define the scope of EPA's review. Thus,
it is necessary for EPA - early in the process - to identify the intended, known and
reasonably foreseen circumstances of manufacture, processing, distribution in commerce,
use and disposal associated with the chemical. In general, EPA considers (1) intended
14 TSCA section 5(f)(4) requires that EPA consider promulgating a SNUR following a
section 5(e) order, or, if a SNUR is not issued, to publish a statement describing the
reasons the Agency did not pursue such a rulemaking.
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conditions of use to be those identified by the submitter in the section 5(a) notice, (2)
known conditions of use to include ongoing U.S. manufacturing activity occuring under
one of the section 5(h) exemptions, and (3) reasonably foreseen conditions of use to
include those future circumstances of manufacture, processing, distribution, use and
disposal that EPA expects might occur.
The following sections describe EPA's general approach for identifying "reasonably
foreseen" conditions of use, including conditions of use with respect to workers, and the
impact of a submitter's amendments to a new chemical notice on the conditions of use
analysis.
i. Identification of Reasonably Foreseen Conditions of Use. In identifying reasonably
foreseen conditions of use, EPA applies an evidence-based approach supported by
professional judgment, experience, and discretion. EPA considers a variety of
information on uses. For example, EPA reviews chemical references to determine if
a new chemical substance is already currently used outside the U.S., in which case it
may be reasonable to foresee that such use could occur inside the U.S. As another
example, EPA reviews structural analogues and their associated uses.15 When there
is at least one use in common with an intended condition of use for the new chemical,
EPA may determine that it is reasonable to foresee that the new chemical substance
will be used in the same additional way(s) as the associated analogue.
ii. Conditions of Use Involving Workers. In general, EPA's reviews of new chemical
notices include an assessment of worker exposures. Where the submitter identifies
controls to protect workers in the section 5(a) notice, including in any amendments to
the submission, EPA considers those controls as part of the chemical's intended
conditions of use. EPA's initial assessment includes consideration of engineering
controls described in the section 5(a) notice, but not personal protective equipment
(PPE) such as gloves and respirators. If risks are preliminarily identified, EPA then
considers whether the risks would be mitigated by the use of PPE.
The requirements set forth by the Occupational Safety and Health Administration
(OSHA), including OSHA's worker protection standard16 require employers to
provide and have affected employees use PPE wherever it is necessary by reason of
hazards present in the workplace. EPA generally expects the submitter and any future
manufacturers and processors to comply with federal and state laws to protect
workers, including OSHA's worker protection standards. Additionally, because EPA
15 EPA has data (including use information) on tens of thousands of chemicals that were
previously the subject of TSCA section 5 notices and/or exemption applications, and uses
this data in its analyses of potential analogues.
16 See, e.g., 29 CFR § 1910.132(a) and (d), which requires employers to ".. .assess the
workplace to determine if hazards are present, or are likely to be present, which
necessitate the use of personal protective equipment (PPE). If such hazards are present, or
likely to be present, the employer shall... select, and have each affected employee use, the
types of PPE that will protect the affected employee from the hazards identified in the
hazard assessment.
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requires that the original submitter's Safety Data Sheet (SDS) reflects Agency
recommendations to protect workers from risks identified in EPA's assessment,
including PPE and hazard communication, future users of the chemical will have this
information available to them when determining how to comply with OSHA's worker
protection standards. Therefore, unless case-specific facts indicate otherwise, EPA
believes that a chemical is generally not likely to present unreasonable risks to
workers if the use of PPE and/or other exposure controls would mitigate potential
risk.
In certain cases, however, the facts might indicate that the chemical may present
unreasonable risks to workers. For example, there may be circumstances where even
a short lapse in PPE protection may present unreasonable risks (e.g., acute lethality).
In such cases, EPA may issue an order under section 5(e) to reinforce the measures
necessary to protect workers. As another example, if a submitter declines to amend
their notice or associated SDS to align with EPA's assessment on the appropriate type
and level of controls to protect workers, there is a greater chance that both the
submitter and any future user will not take the appropriate actions on worker
protection.
iii. Amendments to Section 5 Notices; Changes to Conditions of Use. Where the
submitters provide written amendments to their submission, EPA generally identifies
the conditions of use in those amended submissions to be the new intended conditions
of use, where appropriate.17 However, conditions of use that were identified in an
initial notice and later omitted in an amended submission may be determined to be
reasonably foreseen conditions of use. Amendments to notices which alter the
conditions of use (e.g., changes to the use types, production volume, manufacturing
process, disposal practices, etc.) may necessitate rework of all or part of the technical
review. It is imperative, therefore, for submitters to submit amendments to EPA, if
any, as early as possible in the review process.
B. Analysis of Information Sufficiency
As discussed earlier in this document, information sufficiency is another key question in
the decision-making process that EPA must address. Whether there is "sufficient
information to permit a reasoned evaluation" on the new chemical substance (or
significant new use) is important in identifying the appropriate determination under
section 5(a)(3). In order to make a determination that a new chemical either "presents
unreasonable risk"18 or is "not likely to present unreasonable risk,"19 EPA must have
"sufficient information to permit a reasoned evaluation." Without sufficient information,
EPA may make a determination of "insufficient information"20 or "insufficient
17 In general, "timely" means early enough in the review process to allow EPA to assess
risks and make a determination within the applicable review period. In some cases,
however, both EPA and the submitter may agree to suspend the review period to allow
for assessment.
18 See TSCA § 5(a)(3)(A), 15 U.S.C. § 2604(a)(3)(A).
19 See TSCA § 5(a)(3)(C), 15 U.S.C. § 2604(a)(3)(C).
20 See TSCA § 5(a)(3)(B)(i), 15 U.S.C. § 2604(a)(3)(B)(i).
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information and may present unreasonable risk."21 Where EPA receives amendments or
supplemental information during the review period, the Agency may need to revisit this
analysis.
In analyzing the issue of information sufficiency, EPA generally considers:
• Whether there is information sufficient to characterize both hazard and exposure
to render those characterizations into a quantitative or robust qualitative
characterization of risk, and
• The level of certainty or confidence in the data used in the risk estimate.
For instance, if EPA's evaluation indicates a particular hazard, EPA's own level of
confidence—i.e., the likelihood—that the animal data indicate potential risk to humans is
a factor in whether the Agency has sufficient information available to permit a reasoned
evaluation.
C. Consideration of SNURfor Reasonably Foreseen Conditions of Use
Where EPA identifies reasonably foreseen conditions of use during review of a section 5
notice, but lacks sufficient information to perform a reasoned evaluation and/or has
identified potential risk concerns associated with a reasonably foreseen condition of use,
EPA may consider whether a SNUR can appropriately address those deficiencies or
concerns. A SNUR designating those reasonably foreseen conditions of use as
"significant new uses" would require any persons who intend to manufacture or process a
chemical substance for those uses to notify EPA before commencing that activity and to
provide EPA with certain hazard, exposure and use information. A SNUR can be an
effective means of ensuring that any manufacturing or processing activity for the
reasonably foreseen conditions of use would first be subject to review by EPA, and,
further restriction where appropriate.
D. Decision-Making Logic
The following figure represents the general logic flow for new chemical decision-making
under TSCA, beginning with the questions described in this section and, subsequently,
the different pathways leading to determinations under section 5(a)(3) and associated risk
management actions:
21 See TSCA § 5(a)(3)(B)(ii)(I), 15 U.S.C. § 2604(a)(3)(B)(ii)(I).
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Figure 1: TSCA Section 5(a)(3) Determination Pathways.
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V Section 5 Determinations
This section discusses the five specific determinations under section 5(a)(3) and some of
the factors EPA generally considers, reflective of the guiding principles, concepts and
analyses described above. These discussions are not intended to be interpretations of
what is required by TSCA or the range of discretion afforded by TSCA; nor are they a
recitation of the elements of a specific determination. This document does not purport to
provide a comprehensive rationale for each specific determination type, as the agency's
approach in any individual case will be based on the facts of that case. In addition,
application of the general guiding principles and concepts may result in different decision
paths, and certain cases may present circumstances that are not addressed in these
discussions or that warrant different approaches from those set out here.
Presents Unreasonable Risk - TSCA Section 5(a)(3)(A)
• EPA concludes that there is sufficient information to permit a reasoned
evaluation. That is, data (e.g., data for the chemical substance, an analogous
substance, from a predictive model, a structural alert, or other appropriate
sources) are adequate to characterize, with an acceptable degree of certainty, the
hazard of the substance and/or its metabolite(s), components, or degradation
products, and its exposure potential.
• Health or environmental risks under certain or all conditions of use are above risk
benchmarks.22
• Risk-related factors—such as severity of endpoint (e.g., developmental effects vs.
dermal irritation), reversibility of effect, or exposure-related considerations—lead
EPA to determine that the risks are unreasonable under some or all conditions of
use.
• Where reasonably foreseen conditions of use have been identified, EPA has not
proposed or finalized a SNUR that would require review and regulation of
reasonably foreseen conditions of use that would present an unreasonable risk
before they occur.
• EPA must follow this determination with further appropriate action under 5(f) to
address the unreasonable risk.
Not Likely to Present Unreasonable Risk - TSCA Section 5(a)(3)(C)
• EPA concludes that there is sufficient information to conduct a reasoned
evaluation. That is, data (e.g., data for the chemical substance, for an analogous
substance, from a predictive model, a structural alert, or other appropriate
sources) are adequate to characterize, with an acceptable degree of certainty, the
hazard of the substance and/or its metabolite(s), components, or degradation
products, and its exposure potential.
• Health and environmental risks for the conditions of use are below risk
benchmarks; or health and environmental risks are above the appropriate
22 "Benchmarks" in this document means estimated risks above which EPA generally has
had concern. For example, a 1 x 10"6 cancer risk estimate has often been considered a
"benchmark" above which EPA has concerns for exposure to the general population.
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benchmarks, but other risk-related factors—such as severity of endpoint,
reversibility of effect, or exposure-related considerations (duration, magnitude,
population, etc.), or others—lead EPA to determine that the chemical is not likely
to present a risk that is unreasonable.
• In certain cases, EPA has proposed or finalized a SNUR that would require
review and regulation (if appropriate) of reasonably foreseen conditions of use
that might otherwise present unreasonable risks or for which the Agency lacks
sufficient information to conduct a reasoned evaluation.
• EPA must, in accordance with TSCA section 5(g), follow this determination with
a public statement regarding the findings that support the determination.
Insufficient Information to Permit a Reasoned Evaluation - TSCA Section
5(a)(3)(B)(i)
• EPA determines based on the facts before the Agency that there is insufficient
information to conduct a reasoned evaluation under one or more conditions of
use. That is, data (e.g., data for the chemical substance, for an analogous
substance, from a predictive model, a structural alert, or other appropriate
sources) are inadequate to characterize, with an acceptable degree of certainty, the
hazard of the substance and/or its metabolite(s), components, or degradation
products, and/or its exposure potential under one or more conditions of use.
• EPA has not proposed or finalized a SNUR that would require review and
regulation (if appropriate) of reasonably foreseen conditions of use that might
otherwise present concerns or for which the Agency lacks sufficient information
to conduct a reasoned evaluation.
• EPA must issue an order pursuant to section 5(e) restricting the chemical as
necessary to protect against unreasonable risk. EPA may call for additional
testing in such orders.
• Pursuant to section 5(f)(4), EPA must also consider issuing a SNUR that would
conform to the restrictions in the order, or publish a statement describing the
reasons for not taking such action.
Insufficient Information to Permit a Reasoned Evaluation and May Present
Unreasonable Risk - TSCA Section 5(a)(3)(B)(ii)(I)
• EPA determines based on the facts that the data (e.g., data for the chemical
substance, for an analogous substance, from a predictive model, a structural alert,
or other appropriate sources) indicate potential health or environmental concerns
for the substance and/or its metabolite(s), components, or degradation products
under one or more conditions of use such that the chemical may present an
unreasonable risk.
• However, there is a high level of uncertainty associated with the data used and the
identified risk(s).
• As such, EPA determines that there is insufficient information to conduct a
reasoned evaluation under one or more conditions of use. That is, data are
inadequate to characterize, with an acceptable degree of certainty, the hazard of
the substance and/or its metabolite(s), components, or degradation products,
and/or its exposure potential under one or more conditions of use.
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• EPA has not proposed or finalized a SNUR that would require review and
regulation (if appropriate) of reasonably foreseen conditions of use that otherwise
present concerns or for which the Agency lacks sufficient information to conduct
a reasoned evaluation.
• EPA must issue an order pursuant to section 5(e) restricting the chemical as
necessary to protect against unreasonable risk. EPA may call for additional
testing in such orders.
• Pursuant to section 5(f)(4), EPA must also consider issuing a SNUR that would
conform to the restrictions in the order, or publish a statement describing the
reasons for not taking such action.
Produced in Substantial Quantities; and May Reasonably be Anticipated to Enter
the Environment in Substantial Quantities or May be Significant or Substantial
Human Exposure - TSCA Section 5(a)(3)(B)(ii)(II)
• As a result of the review, and guided by EPA's established criteria23, EPA
determines that the substance (A) is or will be produced in substantial quantities,
and (B) the substance either enters or may reasonably be anticipated to enter the
environment in substantial quantities or there is or may be significant or
substantial human exposure.
• EPA has made the "may reasonably be anticipated" finding based on evidence,
knowledge, or experience to suggest that this finding is appropriate, in a manner
similar to its general approach for identifying reasonably foreseen conditions of
use.
• EPA must follow this determination with an order pursuant to section 5(e)
restricting the chemical where necessary to protect against unreasonable risk.
EPA may call for additional testing in such orders.
• Pursuant to section 5(f)(4), EPA must also consider issuing a SNUR that would
conform to the restrictions in the order, or publish a statement describing the
reasons for not taking such action.
23 See EPA's Exposure-Based Policy under Section 5 of TSCA, available online here:
https://www.epa.gov/reviewing-new-chemicals-under-toxic-substances-control-act-
tsca/exposure-based-policy-under-section
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