[Federal Register Volume 88, Number 144 (Friday, July 28, 2023)]
[Proposed Rules]
[Pages 49180-49228]
[FR Doc No: 2023-15326]

Vol. 88

Friday,

No. 144

July 28, 2023

Part IV

Environmental Protection Agency

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40 CFR Part 751

Carbon Tetrachloride (CTC); Regulation Under the Toxic Substances
Control Act (TSCA); Proposed Rule

Federal Register / Vol. 88, No. 144 / Friday, July 28, 2023 /
Proposed Rules

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 751

[EPA-HQ-OPPT-2020-0592; FRL-8206-01-OCSPP]
RIN 2070-AK82

Carbon Tetrachloride (CTC); Regulation Under the Toxic Substances
Control Act (TSCA)

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
address the unreasonable risk of injury to human health presented by
carbon tetrachloride (CTC) under its conditions of use as documented in
EPA's 2020 Risk Evaluation for Carbon Tetrachloride and 2022 Revised
Unreasonable Risk Determination for Carbon Tetrachloride pursuant to
the Toxic Substances Control Act (TSCA). CTC is a volatile, organic
compound that is primarily used as a feedstock (i.e., processed as a
reactant) in the making of products such as refrigerants, aerosol
propellants, and foam-blowing agents. TSCA requires that EPA address by
rule any unreasonable risk of injury to health or the environment
identified in a TSCA risk evaluation and apply requirements to the
extent necessary so that the chemical no longer presents unreasonable
risk. EPA determined that CTC presents an unreasonable risk of injury
to health due to cancer from chronic inhalation and dermal exposures
and liver toxicity from chronic inhalation, chronic dermal, and acute
dermal exposures in the workplace. To address the identified
unreasonable risk, EPA is proposing under TSCA to establish workplace
safety requirements for most conditions of use, including the condition
of use related to the making of low Global Warming Potential (GWP)
hydrofluoroolefins (HFOs), prohibit the manufacture (including import),
processing, distribution in commerce, and industrial/commercial use of
CTC for conditions of use where information indicates use of CTC has
already been phased out, and establish recordkeeping and downstream
notification requirements. The use of CTC in low GWP HFOs is
particularly important in the Agency's efforts to support the American
Innovation and Manufacturing Act of 2020 (AIM Act) and the Kigali
Amendment to the Montreal Protocol on Substances that Deplete the Ozone
Layer, which was ratified on October 26, 2022.

DATES: Comments must be received on or before September 11, 2023. Under
the Paperwork Reduction Act (PRA), comments on the information
collection provisions are best ensured of consideration if the Office
of Management and Budget (OMB) receives a copy of your comments on or
before August 28, 2023.

ADDRESSES: Submit your comments, identified by docket identification
(ID) number EPA-HQ-OPPT-2020-0592, through the Federal eRulemaking
Portal at https://www.regulations.gov. Follow the online instructions
for submitting comments. Do not submit electronically any information
you consider to be Confidential Business Information (CBI) or other
information whose disclosure is restricted by statute. Additional
instructions on commenting or visiting the docket, along with more
information about dockets generally, is available at https://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT: For technical information contact:
Claudia Menasche, Existing Chemicals Risk Management Division (7404M),
Office of Pollution Prevention and Toxics, Environmental Protection
Agency, 1200 Pennsylvania Ave. NW, Washington, DC 20460-0001; telephone
number<PHONE_NUMBER>; email address: [email protected].
    For general information contact: The TSCA-Hotline, ABVI-Goodwill,
422 South Clinton Ave., Rochester, NY 14620; telephone number: (202)
554-1404; email address: [email protected].

SUPPLEMENTARY INFORMATION:

I. Executive Summary

A. Does this action apply to me?

    You may be potentially affected by this action if you manufacture
(defined under TSCA to include import), process, distribute in
commerce, use, or dispose of CTC. The following list of 2022 North
American Industrial Classification System (NAICS) codes is not intended
to be exhaustive, but rather provides a guide to help readers determine
whether this document applies to them. Potentially affected entities
may include:
     NAICS code 325--Chemical Manufacturing;
     NAICS code 327--Nonmetallic Mineral Product Manufacturing;
     NAICS code 331--Primary Metal Manufacturing;
     NAICS code 562--Waste Management and Remediation Services;
     NAICS code 325110--Petrochemical Manufacturing;
     NAICS code 325120--Industrial Gas Manufacturing;
     NAICS code 325180--Other Basic Inorganic Chemical
Manufacturing;
     NAICS code 325194--Cyclic Crude, Intermediate, and Gum and
Wood Chemical Manufacturing;
     NAICS code 325199--All Other Basic Organic Chemical
Manufacturing;
     NAICS code 325211--Plastics Material and Resin
Manufacturing;
     NAICS code 325320--Pesticide and Other Agricultural
Chemical Manufacturing;
     NAICS code 325998--All Other Miscellaneous Chemical
Product and Preparation Manufacturing;
     NAICS code 327310--Cement Manufacturing;
     NAICS code 327992--Ground or Treated Mineral and Earth
Manufacturing;
     NAICS code 331410--Nonferrous Metal (except Aluminum)
Smelting and Refining;
     NAICS code 562211--Hazardous Waste Treatment and Disposal;
and
     NAICS code 562213--Solid Waste Combustors and
Incinerators.
    This action may also affect certain entities through pre-existing
import, including import certification, and export notification rules
under TSCA. Persons who import any chemical substance governed by a
final TSCA section 6(a) rule are subject to the TSCA section 13 (15
U.S.C. 2612), which requires that the Secretary of the Treasury
``refuse entry into the customs territory of the United States'' of any
substance, mixture, or article containing a chemical substance or
mixture that fails to comply with any rule issued under TSCA or that
``is offered for entry in violation'' of TSCA or certain rules or
orders issued under TSCA, including rules issued under TSCA section
6(a). Persons who import any chemical substance in bulk form, as part
of a mixture, or as part of an article (if required by rule) are also
subject to TSCA section 13 import certification requirements and the
corresponding regulations at 19 CFR 12.118 through 12.127; see also 19
CFR 127.28. Those persons must certify that the shipment of the
chemical substance complies with all applicable rules and orders under
TSCA. The EPA policy in support of import certification appears at 40
CFR part 707, subpart B. In addition, any persons who export or intend
to export a chemical substance that is the subject of this proposed
rule are subject to the export notification provisions of TSCA section
12(b) (15 U.S.C. 2611(b)), and must comply with the export notification
requirements in 40 CFR part 707, subpart D.
    If you have any questions regarding the applicability of this
proposed action

to a particular entity, consult the technical information contact
listed under FOR FURTHER INFORMATION CONTACT.

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

    Under TSCA section 6(a) (15 U.S.C. 2605(a)), if the U.S.
Environmental Protection Agency (hereinafter EPA or ``the Agency'')
determines through a TSCA section 6(b) risk evaluation that a chemical
substance presents an unreasonable risk of injury to health or the
environment, EPA must by rule apply one or more requirements listed in
section 6(a) to the extent necessary so that the chemical substance or
mixture no longer presents such risk.

C. What action is the Agency taking?

    Pursuant to TSCA section 6(b), EPA determined that CTC presents an
unreasonable risk of injury to health, without consideration of costs
or other nonrisk factors, including an unreasonable risk to potentially
exposed or susceptible subpopulations (PESS) identified as relevant to
the 2020 Risk Evaluation for Carbon Tetrachloride, under the conditions
of use (Refs. 1, 2, and 3). A detailed description of the conditions of
use that drive EPA's determination that CTC presents an unreasonable
risk is provided in Unit III.B.1. Accordingly, to address the
unreasonable risk, EPA is proposing, under TSCA section 6(a) to:
    (i) Require a CTC workplace chemical protection program (WCPP),
which would include an existing chemical exposure limit (ECEL) of 0.03
ppm as an 8-hour time-weighted average (TWA) to address risk from
inhalation exposure in combination with direct dermal contact controls
(DDCC) for the following conditions of use. EPA is also proposing
working with the regulated community and industrial hygiene experts to
develop methodologies to measure CTC concentrations at or below the
ECEL. The WCPP would apply to the manufacturing (including import) of
CTC and other conditions of use which account for essentially all of
the production volume of CTC (Ref. 4), as outlined in Unit IV.A.1.:
     Domestic manufacture;
     Import;
     Processing as a reactant in the production of HCFCs, HFCs,
HFOs, and perchloroethylene (PCE);
     Incorporation into formulation, mixture or reaction
products in agricultural products manufacturing and other basic organic
and inorganic chemical manufacturing;
     Repackaging for use as a laboratory chemical;
     Recycling;
     Industrial and commercial use as an industrial processing
aid in the manufacture of agricultural products;
     Industrial and commercial use in the elimination of
nitrogen trichloride in the production of chlorine and caustic soda;
and
     Disposal.
    (ii) Require use of a fume hood and dermal personal protective
equipment (PPE) for the industrial and commercial use as a laboratory
chemical, as outlined in Unit IV.A.2.;
    (iii) Prohibit these additional conditions of use, for which the
Agency understands use of CTC has already been phased out, as outlined
in Unit IV.A.3.:
     Incorporation into formulation, mixture or reaction
products in petrochemical-derived manufacturing;
     Industrial and commercial use as an industrial processing
aid in the manufacture of petrochemicals-derived products;
     Industrial and commercial use in the manufacture of other
basic chemicals (including manufacturing of chlorinated compounds used
in solvents, adhesives, asphalt, and paints and coatings), except for
use in the elimination of nitrogen trichloride in the production of
chlorine and caustic soda (for which EPA is proposing a WCPP);
     Industrial and commercial use in metal recovery;
     Industrial and commercial use as an additive; and
     Industrial and commercial use in specialty uses by the
U.S. Department of Defense (DoD).
    (iv) Require manufacturers (including importers), processors, and
distributors to provide downstream notification of the requirements, as
outlined in Unit IV.A.4.
    (v) Require recordkeeping, as outlined in Unit IV.A.4.
    EPA notes that not all TSCA conditions of use of CTC are subject to
regulation under this proposal. As described in the 2020 Risk
Evaluation for Carbon Tetrachloride (Ref. 1) and the 2022 Revised
Unreasonable Risk Determination for Carbon Tetrachloride (Ref. 3), two
conditions of use of CTC do not drive the unreasonable risk:
distribution in commerce and processing as a reactant/intermediate in
reactive ion etching. EPA is not proposing any restrictions for the
processing of CTC as a reactant/intermediate in reactive ion etching.
    However, under TSCA section 6(a), EPA may select from among a suite
of risk management requirements in TSCA section 6(a), including
requirements related to distribution in commerce, as part of its
regulatory options to address the unreasonable risk; EPA's proposed
regulatory action and primary alternative regulatory action include
prohibitions on the distribution in commerce of CTC for certain
downstream conditions of use.
    The 2020 Risk Evaluation (Ref. 1) and the 2022 Revised Unreasonable
Risk Determination (Ref. 3) contain the full list of CTC's conditions
of use that were evaluated for risk to health or the environment. The
term ``conditions of use'' is defined in TSCA section 3(4) to mean the
circumstances under which a chemical substance is intended, known, or
reasonably foreseen to be manufactured, processed, distributed in
commerce, used, or disposed of. As mentioned, a detailed description of
the conditions of use that drive EPA's determination that CTC presents
an unreasonable risk is provided in Unit III.B.1. In addition, Unit
III.B.2. contains a description of the conditions of use that do not
drive the unreasonable risk of CTC.
    In addition, EPA is proposing to amend the general provision of 40
CFR part 751, subpart A, to define ``authorized person,'' ``direct
dermal contact,'' ``ECEL,'' ``exposure group,'' ``owner or operator,''
``potentially exposed person,'' and ``regulated area'' so that these
definitions may be commonly applied to this and other rules under TSCA
section 6 that would be codified under 40 CFR part 751. EPA is
requesting public comment on all aspects of this proposal.

D. Why is the Agency taking this action?

    Under TSCA section 6(a), ``[i]f the Administrator determines in
accordance with subsection (b)(4)(A) 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
Administrator shall by rule . . . apply one or more of the [section
6(a)] requirements to such substance or mixture to the extent necessary
so that the chemical substance no longer presents such risk.'' CTC was
the subject of a risk evaluation under TSCA section 6(b)(4)(A) that was
issued in November 2020 (2020 Risk Evaluation) (Ref. 1). In addition,
EPA issued a revised unreasonable risk determination for CTC in
December 2022 (Ref. 3), determining that CTC, as a whole chemical
substance, presents an unreasonable risk of injury to health under the
conditions of use. As a result, EPA is proposing to take action to the
extent necessary so that CTC no longer

presents such risk. The unreasonable risk is described in Unit III.B.3.
and the conditions of use that drive the unreasonable risk for CTC are
described in Unit III.B.1.
    EPA is not proposing a complete ban on CTC. CTC is primarily used
as a feedstock to make products such as refrigerants, aerosol
propellants, and foam-blowing agents. Requirements under the Montreal
Protocol and Title VI of the Clean Air Act (CAA), which were included
in the CAA Amendments of 1990 and are codified at 42 U.S.C. Chapter 85,
Subchapter VI, led to a phaseout of CTC production in the United States
for most non-feedstock domestic uses, such as degreasers and fire
suppressants. In addition, the Consumer Product Safety Commission
(CPSC) banned the use of CTC in consumer products (excluding
unavoidable residues not exceeding 10 ppm atmospheric concentration) in
1970. The Agency has considered the benefits of CTC for various uses as
required under TSCA section 6(c)(2)(A) and (B), and recognizes that
continued use of CTC in some TSCA conditions of use should be
maintained for several reasons. The use of CTC may provide benefits
that complement the Agency's efforts to address climate-damaging HFCs
under the AIM Act and the Kigali Amendment to the Montreal Protocol,
and supporting human health and environmental protection under these
programs. In addition, the use of CTC may provide other benefits due to
certain unique properties of CTC (e.g., it does not react with the
process gasses when used as a process agent in the manufacture of
agricultural products (Ref. 5). Finally, strict workplace controls can
be implemented to address unreasonable risk across many conditions of
use. For some workplaces, EPA understands that existing controls may
already reduce exposures enough to meet the inhalation exposure
concentration limit proposed in this rulemaking or to prevent direct
dermal contact with CTC. For these reasons, this rule proposes to allow
CTC's continued use with additional worker protection to address
unreasonable risk for several conditions of use, including the
processing of CTC as a reactant in the production of HFOs.

E. What are the estimated incremental impacts of this Action?

    EPA's Economic Analysis of the estimated incremental impacts
associated with this rulemaking can be found in the rulemaking docket
(Ref. 4). As described in more detail in the Economic Analysis and in
Units VI.D. and X.D., EPA's estimate of the incremental costs of this
proposed rule is $18.8 million per year annualized over 20-years at a
3% discount rate and $18.5 million per year at a 7% discount rate (Ref.
4). The estimated cost of the primary alternative regulatory action is
$2.3 million per year annualized over 20-years at both a 3% and 7%
discount rate. While the cost of the proposed regulatory action is
higher than the cost of the primary alternative regulatory action, the
proposed regulatory action is the action with the least uncertainty
regarding the protection afforded to workers, requires regulated
entities to consider more protective controls in the hierarchy, and
lessens the burden on workers. Under the WCPP, regulated entities would
be required to implement the hierarchy of controls and only consider
respirators and dermal PPE after all other steps have been taken to
reduce exposures using other and more effective controls in the
hierarchy (Ref. 8). The primary alternative regulatory action, on the
other hand, would neither allow nor require regulated entities to
consider other, more effective exposure controls in the hierarchy. In
addition, the Agency recognizes that workplaces have unique processes
and equipment in place and that varying levels of respiratory APFs may
be needed for different workplaces. Therefore, there is uncertainty as
to whether a specific respiratory APF or a dermal PPE would be
sufficient for all workplaces so that CTC no longer presents
unreasonable risk. Finally, there is an unquantified cost to workers
associated with prolonged use of respirators, which could interfere
with work tasks. The potential for respirator use to cause discomfort
and productivity losses could lead companies to offer higher wages as
compensation, but the extent of this effect is unknown and thus
unquantified. To the extent that this unquantified cost of respirator
use applies more to prescriptive controls, it is an unmonetized benefit
of the proposed regulatory action relative to the primary alternative
action. More details regarding the rationale for the proposed
regulatory action and the primary alternative regulatory action are in
Unit IV and Unit V. The costs are estimated as incremental to baseline
conditions, including current use of personal protective equipment. The
costs represent a high-end cost estimate because the high estimates for
the number of entities and workers affected by the regulation were
used. To the extent that EPA's approach overestimates the number of
entities subject to the regulation, actual realized costs of this
action will be lower. These costs take into consideration the proposed
requirements to mitigate unreasonable risk of injury to health from CTC
under the conditions of use. Costs are higher for the proposed action
compared to the primary alternative action because the proposed action
would require a WCPP for many conditions of use, which includes
monitoring and WCPP recordkeeping requirements that are more costly
than the primary alternative action's prescriptive controls
requirement. In the primary alternative action, facilities will not
incur monitoring or WCPP recordkeeping costs, but will need to provide
a respirator to all employees. The cost of the primary alternative
action's prescriptive controls option includes the PPE. The cost
estimates include the equipment itself, as well as the costs of a
medical evaluation, fit testing, and equipment cleaning that ensure
proper use and maintenance of the PPE. There is an unquantified cost to
workers associated with prolonged use of respirators, which could
interfere with work tasks. The potential for respirator use to cause
discomfort and productivity losses could lead companies to offer higher
wages as compensation, but the extent of this effect is unknown and
thus unquantified. To the extent that this unquantified cost of
respirator use applies more to prescriptive controls, it is an
unmonetized benefit of the proposed regulatory action relative to the
primary alternative action. More details regarding the rationale for
the proposed regulatory action and the primary alternative regulatory
action are in Unit IV and Unit V
    Unit IV. details which actions apply to which conditions of use.
EPA estimates that 30 firms associated with 71 sites may be
manufacturing (including importing), processing, or releasing CTC.
    Industry is expected to incur costs associated with performing
inspections, documenting efforts to meet the regulatory requirements
associated with the WCPP, including reducing exposure and occurrences
of exposure, monitoring, respirators and dermal PPE, training on the
use of respirators and dermal PPE, and notification and recordkeeping
burdens and costs associated with the WCPP. Industry is also expected
to incur equipment costs associated with dermal PPE for laboratory use.
EPA assumes that industry would not incur equipment costs associated
with the fume hood requirement for laboratory settings because they are
considered to be part of baseline industry practices. All manufacturers
(including importers),

processors, and distributors will bear downstream notification and
recordkeeping costs.
    EPA estimates that the proposed rule would affect at least four
small entities. EPA compared the highest annualized per-facility cost
of the proposed regulatory action with ultimate parent company annual
revenues of the affected small businesses. EPA found impacts under 1%
of annual revenues for three of the four small entities. One small
entity was estimated to have a cost-to-revenue impact ratio greater
than 1%, and that entity would incur a cost-to-impact ratio of between
1% and 3%. EPA requests public comments regarding the number of small
businesses subject to the proposed rule and the potential impacts of
the proposed rule on these small businesses.
    EPA's Economic Analysis for the rule monetized the benefits from
avoided cases of adrenal and liver cancers. Cancer avoidance benefits
are calculated based on reductions in inhalation exposure using the
2020 Risk Evaluation for Carbon Tetrachloride (Ref. 1) for those uses
which are continuing but with a WCPP in place. Therefore, benefits are
only calculated for the WCPP in the proposed regulatory action, which
could include respiratory protection, and prescriptive workplace
controls in the primary alternative regulatory action. The estimated
monetized benefit of the proposed regulatory action ranges from
approximately $0.09 to $0.1 million per year annualized over 20-years
at a 3% discount rate and from $0.04 to $0.07 million per year at a 7%
discount rate. The estimated monetized benefit of the primary
alternative regulatory action is $.09 to $.1 million per year
annualized over 20-years at a 3% discount rate and $.04 to $.07 million
per year at a 7% discount rate. The APFs of respirators required under
the prescriptive workplace controls primary alternative regulatory
action are higher on average than those expected to be required based
on projected monitoring outcomes under the ECEL as part of the WCPP
under the proposed regulatory action. To estimate the costs and
benefits of respirators under the ECEL, the Economic Analysis generated
a likely distribution of air monitoring outcomes at CTC facilities.
This distribution was used to project the number of facilities that
would require each APF. These estimates are subject to uncertainties,
and there could be facilities with higher or lower air exposures than
estimated in the Economic Analysis. In practice, the WCPP would require
facility personnel to select appropriate PPE based on actual monitored
levels to ensure adequate protection. Under the prescriptive workplace
controls in the primary alternative regulatory action, the APFs of
respirators for each condition of use are based on high-end exposure
scenarios to ensure that workers are sufficiently protected, without
accounting for differences in air exposures across facilities,
including the unique processes and engineering controls that may
already be implemented. This results in more workers wearing higher
APFs in the primary alternative regulatory action. The quantified
benefits from the primary alternative regulatory action are comparable
to those of the proposed action, with a difference of less than five
percent between the benefits of the two regulatory options.
    Using the high-end estimates for the number of entities and workers
affected by the proposed regulation, the monetized net benefit of the
proposed regulatory action, which is negative, is -$18.7 million per
year annualized over 20-years at a 3% discount rate and ranges from -
$18.5 to -$18.4 million per year at a 7% discount rate. The monetized
net benefit of the primary alternative regulatory action is also
negative and ranges from -$2.3 to -$2.2 million per year annualized
over 20-years at a 3% discount rate and is -$2.3 million per year at a
7% discount rate. The range in the monetized net benefits estimate at
each discount rate reflects uncertainty in cancer risk reductions given
the shorter exposure durations being considered and the life stage at
which the changes in exposure occur. Although the estimated monetized
net benefits are negative, there are also non-monetized benefits due to
other potential avoided adverse health effects associated with CTC
exposure, including liver, reproductive, renal, developmental, and
central nervous system (CNS) toxicity endpoints. These are serious
health endpoints, even though the change in risk due to CTC exposure
was not quantified in the 2020 Risk Evaluation for Carbon
Tetrachloride.
    Section 6.6 of the Economic Analysis, addressing environmental
justice impacts, provides sociodemographic data on communities and
workers in industries affected by the rule and people that live in
proximity to potentially affected facilities. EPA analyzed the baseline
conditions facing communities near CTC and HFO manufacturing facilities
as well as those of workers in the same industry and county as CTC
facilities and HFO manufacturing facilities.
    The environmental justice analysis found that, across the entire
population within 1- and 3-miles of CTC facilities, there are higher
percentages of people who identify as Black and living below the
poverty line and a similar percentage of people who identify as
Hispanic compared to the national averages. CTC facilities are
concentrated in Texas and Louisiana, especially near Houston and Baton
Rouge.

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

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

II. Background

A. Overview of Carbon Tetrachloride

    This proposed rule applies to CTC (CASRN 56-23-5) and is
specifically intended to address the unreasonable risks of injury to
health EPA identified in the 2020 Risk Evaluation for Carbon
Tetrachloride (Ref. 1) and the 2022 Revised Unreasonable Risk
Determination for Carbon Tetrachloride (Ref. 3), as described in Unit
III.B.3. CTC is a volatile organic compound that is primarily used as a
feedstock in the production of HCFCs, HFCs, and HFOs. EPA identified
liver toxicity and cancer adverse effects from chronic inhalation and
dermal exposures, as well as liver toxicity from acute dermal exposures
in the workplace as the basis for the unreasonable risk determination
for CTC (Ref. 1, 2, and 3).
    According to data collected as a result of EPA's 2016 and 2020
Chemical Data Reporting (CDR) Rule, in Reporting Years (RY) 2015 and
2019, between 100 and 250 million pounds of CTC were manufactured or
imported in the United States (Ref. 4). CTC's use as a feedstock in the
production of HCFCs, HFCs, and HFOs is described in Unit III.B.1., with
a description of proposed requirements to address the unreasonable risk
in Unit IV.A.

B. Regulatory Actions Pertaining to Carbon Tetrachloride

    CTC is subject to numerous State, Federal, and international
regulations restricting and regulating its use; a summary of the
regulatory actions pertaining to CTC is in the docket (Refs. 1 and 6).

C. Consideration of Occupational Safety and Health Administration
(OSHA) Occupational Health Standards in TSCA Risk Evaluations and TSCA
Risk Management Actions

    Although EPA must consider and factor in, to the extent
practicable, certain non-risk factors as part of TSCA section 6(a)
rulemaking (see TSCA section 6(c)(2)), EPA must nonetheless still
ensure that the selected regulatory requirements apply ``to the extent
necessary so that the chemical substance or mixture no longer presents
[unreasonable] risk.'' 15 U.S.C. 2605(a). This requirement to eliminate
unreasonable risk is distinguishable from approaches mandated by some
other laws, including the Occupational Safety and Health Act (OSH Act),
which includes both significant risk and feasibility (technical and
economic) considerations in the setting of standards.
    Congress intended for EPA to consider occupational risks from
chemicals it evaluates under TSCA, among other potential exposures, as
relevant and appropriate. As noted previously, TSCA section 6(b)
requires EPA to evaluate risks to PESS identified as relevant by the
Administrator. TSCA section 3(12) defines the term ``potentially
exposed or susceptible subpopulation'' as ``a group of individuals
within the general population identified by the Administrator 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.''
    The OSH Act similarly requires OSHA to evaluate risk specific to
workers prior to promulgating new or revised standards and requires
OSHA standards to substantially reduce significant risk to the extent
feasible, even if workers are exposed over a full working lifetime. See
29 U.S.C. 655(b)(5); Indus. Union Dep't, AFL-CIO v. Am. Petroleum
Inst., 448 U.S. 607, 642 (1980) (plurality opinion).
    Thus, the standards for chemical hazards that OSHA promulgates
under the OSH Act share a broadly similar purpose with the standards
that EPA promulgates under TSCA section 6(a). The control measures OSHA
and EPA require to satisfy the objectives of their respective statutes
may also, in many circumstances, overlap or coincide. However, as this
section outlines, there are important differences between EPA's and
OSHA's regulatory approaches and jurisdiction, and EPA considers these
differences when deciding whether and how to account for OSHA
requirements when evaluating and addressing potential unreasonable risk
to workers so that compliance requirements are clearly explained to the
regulated community.
    1. OSHA Requirements.
    OSHA's mission is to ensure that employees work in safe and
healthful conditions. The OSH Act establishes requirements that each
employer comply with the General Duty Clause of the Act (29 U.S.C.
654(a)), as well as with occupational safety and health standards
issued under the Act.
    a. General Duty Clause of the OSH Act.
    The General Duty Clause of the OSH Act requires employers to keep
their workplaces free from recognized hazards that are causing or are
likely to cause death or serious physical harm to employees. The
General Duty Clause is cast in general terms, and does not establish
specific requirements like exposure limits, PPE, or other specific
protective measures that EPA could potentially consider when developing
its risk evaluations or risk management requirements. OSHA, under
limited circumstances, has cited the General Duty Clause for regulating
exposure to chemicals. To prove a violation of the General Duty Clause,
OSHA must prove employer or industry recognition of the hazard, that
the hazard was causing or likely to cause death or serious physical
harm, and a feasible method to eliminate or materially reduce the
hazard was available.
    In rare situations, OSHA has cited employers for violation of the
General Duty Clause where exposures were below a chemical-specific
Permissible Exposure Limit (PEL), a time weighted average (TWA) based
on an employee's average airborne exposure in any 8-hour work shift of
a 40-hour work week which shall not be exceeded (Ref. 7). In such
situations, OSHA must demonstrate that the employer had actual
knowledge that the PEL was inadequate to protect its employees from
death or serious physical harm. Because of the heavy evidentiary burden
on OSHA to establish violations of the General Duty Clause, it is not
frequently used to cite employers for employee exposure to chemical
hazards.
    b. OSHA Standards.
    OSHA standards are issued pursuant to the OSH Act and are found in
title 29 of the CFR. There are separate standards for general industry,
construction, maritime and agriculture sectors, and general standards
applicable to a number of sectors (e.g., OSHA's Respiratory Protection
standard). OSHA has numerous standards that apply to employers who
operate chemical manufacturing and processing facilities, as well as to
downstream employers whose employees may be occupationally exposed to
hazardous chemicals.
    OSHA sets legally enforceable limits on the airborne concentrations
of hazardous chemicals, referred to as PELs, established for employers
to protect their workers against the health effects of exposure to
hazardous substances (29 CFR part 1910, subpart Z, part 1915, subpart
Z, and part 1926, subparts D and Z). Under section 6(a) of the OSH Act,
OSHA was permitted an initial 2-year window after the passage of the
Act to adopt ``any national consensus standard and any established
Federal standard.'' 29 U.S.C. 655(a). OSHA used this authority in 1971
to establish PELs that were adopted from Federal health standards
originally set by the U.S. Department of Labor through the Walsh-Healy
Act, in which approximately 400 Occupational Exposure Limits (OELs)
were selected based on the American Conference of Governmental
Industrial Hygienists (ACGIH) 1968 list of Threshold Limit Values
(TLVs). In addition, about 25 exposure limits recommended by the
American Standards Association (now called the American National
Standards Institute) (ANSI) were adopted as PELs.
    Following the 2-year window provided under section 6(a) of the OSH
Act for the adoption of national consensus and existing Federal
standards, OSHA issued health standards following the requirements in
section 6(b) of the Act. OSHA has established approximately 30 PELs
under section 6(b)(5) as part of comprehensive substance-specific
standards that include additional requirements for protective measures
such as use of PPE, establishment of regulated areas, exposure
assessment, hygiene facilities, medical surveillance, and training.
These ancillary provisions in substance-specific OSHA standards further
mitigate residual risk that could be present due to exposure at the
PEL.
    Many OSHA PELs have not been updated since they were established in
1971, including the PEL for CTC. In

many instances, scientific evidence has accumulated suggesting that the
current limits of many PELs are not sufficiently protective. On October
10, 2014, OSHA published a Federal Register document in which it
recognized that many of its PELs are outdated and inadequate for
ensuring protection of worker health (79 FR 61384, October 14, 2014).
In addition, health standards issued under section 6(b)(5) of the OSH
Act must reduce significant risk only to the extent that it was
technologically and economically feasible at the time they were issued.
OSHA's legal requirement to demonstrate that its section 6(b)(5)
standards are technologically and economically feasible at the time
they are promulgated often precludes OSHA from imposing exposure
control requirements sufficient to ensure that the chemical substance
no longer presents a significant risk to workers. As described in that
notice, while new advancements or developments in science and
technology from the time a PEL is promulgated may improve the
scientific basis for making findings of significant risk, technical
feasibility or economic feasibility, OSHA has been unable to update
most of the PELs established in 1971 and they remain frozen at levels
at which they were initially adopted (79 FR 61384, October 10, 2014).
One example of how industries have evolved in the intervening 50 years
as to what is technologically and economically feasible is the
halogenated solvent cleaning industry, which, in response to EPA's
National Emission Standards for Hazardous Air Pollutants (NESHAP)
promulgated under Section 112 of the 1990 CAA Amendments (see National
Emissions Standards for Halogenated Solvent Cleaning, 40 CFR part 63,
subpart T), has made equipment improvements that conserve solvent
resources and reduce workplace exposure.
    In sum, the great majority of OSHA's chemical standards are
outdated or do not sufficiently reduce risk to workers. While it is
possible in some cases that the OSHA standards for some chemicals
reviewed under TSCA will eliminate unreasonable risk, based on EPA's
experience thus far in conducting occupational risk assessments under
TSCA EPA believes that OSHA chemical standards would in general be
unlikely to address unreasonable risk to workers within the meaning of
TSCA, since TSCA section 6(b) unreasonable risk determinations may
account for unreasonable risk to more sensitive endpoints and working
populations than OSHA's risk evaluations typically contemplate, and EPA
is obligated to apply TSCA section 6(a) risk management requirements to
the extent necessary so that the unreasonable risk is no longer
presented.
    Because the requirements and application of TSCA and OSHA
regulatory analyses differ, and because many of OSHA's chemical-
specific standards are based on outdated information regarding the
technological and economic feasibility of the standards and the risks
associated with exposure, it is necessary for EPA to conduct risk
evaluations and, where it finds unreasonable risk to workers, develop
risk management requirements for chemical substances that OSHA also
regulates, and it is expected that EPA's findings and requirements may
sometimes diverge from OSHA's. However, it is also appropriate that EPA
consider the chemical standards that OSHA has already developed to
limit the compliance burden to employers by aligning management
approaches required by the agencies, where alignment will adequately
address unreasonable risk to workers. The following section discusses
EPA's consideration of OSHA standards in its risk evaluation and
management strategies under TSCA.
    2. Consideration of OSHA standards in TSCA risk evaluations.
    When characterizing the risk during risk evaluation under TSCA, EPA
believes it is appropriate to evaluate the levels of risk present in
scenarios where no mitigation measures are assumed to be in place for
the purpose of determining unreasonable risk (see Unit II.C.2.a.). (It
should be noted that there are some cases where scenarios may reflect
certain mitigation measures, such as in instances where exposure
estimates are based on monitoring data at facilities that have existing
engineering controls in place. For example, the Chemical Manufacturing
Area Sources NESHAP, last updated in 2012, requires that certain
chemical manufacturing synthetic area sources that installed controls
obtain a title V permit under the CAA, requiring sources to obtain and
operate in compliance with an operating permit (40 CFR part 63, subpart
VVVVVV) (77 FR 75740, December 21, 2012). Consequently, emissions
monitoring from facilities meeting the NESHAP would reflect emissions
reduction resulting from existing engineering controls already in place
to meet the standards.) In addition, EPA believes it may be appropriate
to also evaluate the levels of risk present in scenarios considering
applicable OSHA requirements as well as scenarios considering industry
or sector best practices for industrial hygiene that are clearly
articulated to the Agency. EPA may evaluate risk under scenarios that
consider industry or sector best practices for industrial hygiene that
are clearly articulated to the Agency, when doing so serves to inform
its risk management efforts. Characterizing risks using scenarios that
reflect different levels of mitigation can help inform potential risk
management actions by providing information that could be used during
risk management to tailor risk mitigation appropriately to address any
unreasonable risk identified (see Unit II.C.2.b. and Unit II.C.3.).
    a. Risk characterization for unreasonable risk determination.
    When making unreasonable risk determinations as informed by TSCA
risk evaluations, EPA cannot assume as a general matter that all
workers are always equipped with and appropriately using sufficient
PPE, although it does not question the veracity of public comments
received on 2020 Risk Evaluation for Carbon Tetrachloride regarding the
occupational safety practices often followed by industry respondents.
When characterizing the risk to human health from occupational
exposures during risk evaluation under TSCA, EPA believes it is
appropriate to evaluate the levels of risk present in scenarios where
PPE is not assumed to be used by workers. This approach of not assuming
PPE use by workers considers the risk to PESS (workers and occupational
non-users (ONUs)) who may not be covered by OSHA standards, such as
self-employed individuals and public sector workers who are not covered
by a State Plan. Mitigation scenarios included in the EPA risk
evaluation in order to inform its risk management efforts (e.g.,
scenarios considering use of PPE) likely represent current practice in
many facilities where companies effectively address worker and
bystander safety requirements. However, the Agency cannot assume that
all facilities across all uses of the chemical substance will have
adopted these practices for the purposes of making the TSCA risk
determination.
    Therefore, EPA makes its determinations of unreasonable risk based
on scenarios that do not assume compliance with OSHA standards,
including any applicable exposure limits or requirements for use of
respiratory protection or other PPE. Making unreasonable risk
determinations based on such scenarios should not be viewed as an
indication that EPA believes there are no occupational safety
protections in place at any location, or that there is

widespread noncompliance with applicable OSHA standards. Rather, it
reflects EPA's recognition that unreasonable risk may exist for
subpopulations of workers that may be highly exposed because they are
not covered by OSHA standards, such as self-employed individuals and
public sector workers who are not covered by an OSHA State Plan, or
because their employer is out of compliance with OSHA standards, or
because EPA finds unreasonable risk for purposes of TSCA
notwithstanding assumed compliance with existing OSHA requirements.
    b. Risk evaluation to inform risk management requirements
    In addition to the scenarios described previously, EPA risk
evaluations may characterize the levels of risk present in scenarios
considering applicable OSHA requirements (e.g., chemical-specific PELs
and/or chemical-specific health standards with PELs and additional
ancillary provisions) as well as scenarios considering industry or
sector best practices for industrial hygiene that are clearly
articulated to the Agency to help inform risk management decisions.
    3. Consideration of OSHA standards in TSCA risk management actions.
    When undertaking risk management actions, EPA: (1) develops
occupational risk mitigation measures to address any unreasonable risk
identified by EPA, striving for compatibility with applicable OSHA
requirements and industry best practices, including appropriate
application of the hierarchy of controls, when those measures would
address an unreasonable risk; and (2) ensures that EPA requirements
apply to all potentially exposed workers in accordance with TSCA
requirements. Consistent with TSCA section 9(d), EPA consults and
coordinates TSCA activities with OSHA and other relevant Federal
agencies for the purpose of achieving the maximum applicability of TSCA
while avoiding the imposition of duplicative requirements.
    Informed by the mitigation scenarios and information gathered
during the risk evaluation and risk management process, the Agency
might propose rules to require risk management practices that may
already be common practice in many or most facilities. Adopting clear,
broadly applicable regulatory standards will foster compliance across
all facilities (ensuring a level playing field) and ensure protections
for all affected workers, especially in cases where current OSHA
standards may not apply to them or not be sufficient to address the
unreasonable risk.
    For evaluation scenarios which involve OSHA chemical-specific PELs,
EPA's risk evaluation in some cases may illustrate that limiting
exposure to OSHA's PEL would result in acceptable levels of risk under
TSCA under certain conditions of use. In these cases, TSCA risk
management requirements could incorporate and reinforce requirements in
OSHA standards and ensure that risks are addressed, including for
circumstances where OSHA requirements are not applicable (e.g., public
sector workers not covered by an OSHA State plan, and self-employed
workers) by asserting TSCA compliance/enforcement as well. EPA's risk
evaluation may also find unreasonable risk under TSCA associated with
some occupational conditions of use, even when the applicable OSHA
requirements are being met. In these cases, EPA would need to develop
risk management requirements beyond those included in OSHA's standards.
    4. Carbon Tetrachloride and OSHA requirements.
    EPA incorporated the considerations described earlier in this unit
in the 2020 Risk Evaluation (Ref. 1), the 2022 Revised Unreasonable
Risk Determination (Ref. 3), and this rulemaking. Specifically, in the
TSCA 2020 Risk Evaluation, EPA presented risk estimates based on
workers' exposures with and without respiratory protection. Additional
consideration of OSHA standards in the 2022 Revised Unreasonable Risk
Determination is discussed further in the Federal Register document of
December 27, 2022 (87 FR 79303) (FRL-9948-02-OCSPP), announcing the
availability of the Final Revised Unreasonable Risk Determination for
Carbon Tetrachloride. In Unit III.B.4. and Unit V., EPA outlines the
importance of considering the hierarchy of controls utilized by the
industrial hygiene community (hereafter referred to as ``hierarchy of
controls'') when developing risk management actions in general, and
specifically when determining if and how regulated entities may meet a
risk-based exposure limit for CTC.
    The hierarchy of controls includes: elimination of the hazard,
substitution with a less hazardous substance, engineering controls,
administrative controls such as training or exclusion zones with
warning signs, and, finally, use of PPE (Ref. 8). Under the hierarchy
of controls, the use of respirators and dermal PPE should only be
considered after all other steps have been taken to reduce exposures.
As discussed in Units IV.A. and V.A.1., EPA's risk management approach
would not rely solely or primarily on the use of respirators and dermal
PPE to address unreasonable risk to workers; instead, EPA is proposing
a WCPP for most conditions of use and prohibitions for certain uses.
The WCPP would require consideration of the hierarchy of controls
before use of respirators and other PPE. The WCPP is discussed in full
in Units IV.A.1. and V.A.1.
    In accordance with the approach described earlier in Unit II.C.3.,
EPA intends for this regulation to be as compatible as possible with
the existing OSHA standards, with additional requirements as necessary
to address the unreasonable risk. One notable difference between the
WCPP and the OSHA standards are the exposure limits. This WCPP would
include an Existing Chemical Exposure Limit (ECEL) of 0.03 ppm as an 8-
hour TWA to address unreasonable risk for cancer and chronic toxicity
for non-cancer effects. EPA recognizes that for CTC, the ECEL would be
significantly lower than the 1971 OSHA PEL (10 ppm as an 8-hour TWA).
In addition to the distinctions in statutory requirements described in
this unit, EPA has identified several factors contributing to the
differences in these levels, summarized here.
    The TSCA ECEL value for CTC is a lower value than the OSHA PEL (and
other existing occupational exposure limits (OELs), discussed in Unit
II.C.5) for many reasons, including the age of the data and studies the
values are based on and that the values may not fully capture either
the complete database of studies considered in the 2020 Risk Evaluation
for Carbon Tetrachloride or more recent advances in modeling and
scientific interpretation of toxicological data applied in the
calculation of the CTC ECEL, in particular CTC's carcinogenicity. EPA
considers the CTC ECEL to represent the best available science under
TSCA section 26(h), because it was derived from information in the 2020
Risk Evaluation for Carbon Tetrachloride, which was subject to peer
review, and was the result of a systematic review process that
investigated the reasonably available information in order to identify
relevant adverse health effects (Ref. 1). Additionally, by using the
information from the 2020 Risk Evaluation for Carbon Tetrachloride, the
ECEL incorporates advanced modeling and peer-reviewed methodologies,
and accounts for exposures to potentially exposed and susceptible
subpopulations, as required by TSCA. For example, the CTC ECEL is based
on a study conducted in 2007, which was rated a high quality study
during the systematic review process and was the principal study used
to derive the IRIS reference concentration for liver effects

(Ref. 1). The data from the 2007 study used to derive the IRIS
reference concentration for liver effects for the CTC ECEL is more
recent than the data OSHA had available when OSHA set the PEL for CTC
in 1971. OSHA attempted to reduce the CTC PEL in 1989 from 10 ppm to 2
ppm after new data about CTC cancer risk became available, but, as
explained later in this unit, the reduced CTC PEL was later vacated by
court order.
    For CTC, the EPA ECEL is an 8-hour occupational inhalation exposure
limit based on liver cancer and takes into consideration the
uncertainties identified in the 2020 Risk Evaluation for Carbon
Tetrachloride (Ref. 9). The ECEL represents the concentration at which
an adult human, including a member of a potentially exposed or
susceptible subpopulation, would be unlikely to suffer adverse effects
if exposed for a working lifetime. EPA has determined as a matter of
risk management policy that ensuring exposures remain at or below the
ECEL will eliminate any unreasonable risk of injury to health driven by
inhalation exposures. In addition to the ECEL, as part of this
rulemaking EPA is proposing an ECEL action level, a value based on two-
thirds of the ECEL, that would trigger additional monitoring to ensure
that workers are not exposed to concentrations above the ECEL.
    For CTC, the ECEL of 0.03 ppm is based on the most sensitive point
of departure (POD) across cancer, chronic non-cancer, and acute
endpoints. EPA identified cancer PODs for inhalation exposures based on
liver tumor effects observed in mice. The chronic PODs for inhalation
exposures are based on a study observing increased fatty changes in
rodent livers. As explained in the ECEL memo, the point of departure
for liver cancer was the basis of the CTC ECEL. Additional information
on the ECEL and how it was derived can be found in Unit IV.A.1.b.i.
Overall, based on strong evidence in highly rated animal studies, the
weight of the scientific evidence supported liver cancer effects
following CTC exposure (Ref. 1). Monitoring data submitted via public
comment by a trade association during the 2020 Risk Evaluation for
Carbon Tetrachloride indicating exposures near or below the ECEL
supports EPA's confidence that meeting the ECEL is feasible for
facilities engaging in the use of CTC (Ref. 10).
    The OSHA PEL for CTC of 10 ppm as an 8-hour TWA was established in
1971 (29 CFR 1910.1000 Table Z-2). OSHA is required to promulgate a
standard that reduces significant risk to the extent that it is
technologically and economically feasible to do so (Ref. 7). A 1989
update to 2 ppm based on a quantitative cancer risk assessment--a level
at which ``residual risk continues to be significant,'' according to
OSHA's 1989 final rule preamble--was later vacated by court order,
reverting to the original PEL of 10 ppm, because the court found OSHA
had not made sufficiently detailed findings that the new PEL would
eliminate significant risk and would be feasible in each industry in
which the chemical was used (see 54 FR 2332, 2679 through2681 ; AFL-CIO
v. OSHA, 965 F.2d 962 (11th Cir. 1992)). Most original PELs were based
on acute health effects only observable at higher concentrations as
more sensitive chronic studies, including the chronic exposure studies
used to inform the CTC ECEL, were not available at the time the PEL was
established (see, e.g., 79 FR 61383, 61388). As discussed in Units
IV.A.1.b.i. and VII.D., the TSCA ECEL represents the best available
science at the time of publication of the 2020 Risk Evaluation for CTC.
As described earlier, in a 2014 request for information OSHA described
how, while new developments in science and technology from the time the
PEL for CTC was established in 1971 may improve the scientific basis
for making findings of significant risk, technical feasibility, or
economic feasibility as required under section 6(b)(5) of the OSH Act,
OSHA has been unable to update the PEL for CTC and it remains at the
level that was originally adopted in 1971 (79 FR 61383, October 10,
2014).
5. Carbon Tetrachloride and Other Occupational Exposure Limits
    EPA is aware of other occupational exposure recommendations or
limits for CTC, including the ACGIH TLV, the California Division of
Occupational Safety and Health (Cal/OSHA) PEL, and the National
Institute for Occupational Safety and Health (NIOSH) Recommended
Exposure Limit (REL).
a. ACGIH TLV
    The 1996 ACGIH TLV is 5 ppm (Ref. 11). This 8-hour TWA TLV
recommended by the ACGIH in 1996 has a different endpoint than the CTC
ECEL and instead of being based on the 2007 study indicating a liver
cancer endpoint is based on broad liver toxicity that was observed in
several earlier studies in rodents, primates, and humans exposed to CTC
concentrations of 10 ppm and above. Additionally, a PBPK model used by
ACGIH to develop a Short-Term Exposure Limit (STEL) TLV indicated that
acute exposure at 10 ppm results in equivalent liver metabolism as a
chronic occupational exposure at 5 ppm, which results in a much lower
liver concentration than the level that caused toxicity in rats.
Therefore, ACGIH recommended an 8-hour TWA TLV of 5 ppm as long as the
15-minute STEL did not exceed 10 ppm. However, even ACGIH's TLV report
acknowledges that the 5 ppm value is not protective of susceptible
subpopulations, and there were no uncertainty factors assigned to
account for inter- or intra-species variability (Ref. 11).
Additionally, while ACGIH designated CTC as a suspected human
carcinogen in 2001 based on a threshold mode of action, it did not
update its 1996 TLV to derive
    a TLV based on cancer.
    b. NIOSH REL.
    The 1975 NIOSH REL for CTC is 2 ppm was originally based on
systemic effects and local effects on the skin and eyes. The 1975 NIOSH
REL for CTC was a 10-hour TWA in a 40-hour work week (Ref. 12). In
1989, as part of a joint project with OSHA, NIOSH changed the 10-hour
TWA to a 60-minute STEL and added the Ca designation (potential
occupational carcinogen). In general, RELs that are set as STELs or
ceilings instead of 8- or 10-hour TWAs are typically based on concern
for acute health effects, but in the case of CTC, NIOSH also recognized
its carcinogenicity.
    c. Cal/OSHA PEL.
    Generally, Cal/OSHA updates its PELs every other year. The Cal/OSHA
PEL is 2 ppm, lower than the 1971 OSHA PEL of 10 ppm, and equivalent to
the NIOSH REL and the vacated 1989 OSHA PEL, which was based on a
quantitative cancer risk assessment but was acknowledged by OSHA to
leave significant residual risk. Despite the Cal/OSHA PEL being
equivalent to the vacated 1989 OSHA PEL based on cancer, Cal/OSHA did
not perform a quantitative cancer risk assessment, and the Cal/OSHA PEL
cites the 1989 NIOSH 60-min STEL.
    D. Summary of EPA's Risk Evaluation Activities on Carbon
Tetrachloride
    In December 2016, EPA selected CTC as one of the first 10 chemicals
for risk evaluation under TSCA section 6. EPA published the Scope of
the Risk Evaluation for Carbon Tetrachloride in July 2017 (82 FR 31592,
July 7, 2017) (FRL-9963-57), and, after receiving public comments,
published the problem formulation in June 2018 (83 FR 26998, June 11,
2018) (FRL-9978-40). In January 2020, EPA published a draft risk
evaluation (85 FR 4658, January 27, 2020) (FRL-10003-92), and, after
public comment and peer review by the Science Advisory Committee on

Chemicals (SACC), EPA issued the Risk Evaluation for Carbon
Tetrachloride in November 2020 in accordance with TSCA section 6(b)
(Ref. 1) (85 FR 70147, November 4, 2020) (FRL-10015-51). EPA
subsequently issued a Draft Revised Unreasonable Risk Determination for
Carbon Tetrachloride in August 2022 (87 FR 52766, August 29, 2022)
(FRL-9948-01-OCSPP), and, after public notice and receipt of comments,
published a Revised Unreasonable Risk Determination for Carbon
Tetrachloride in December 2022 (Ref. 3) (87 FR 79303, December 27,
2022) (FRL-9948-02-OCSPP). The 2020 Risk Evaluation for Carbon
Tetrachloride and supplemental materials are in docket ID No. EPA-HQ-
OPPT-2019-0499, and the 2022 Revised Unreasonable Risk Determination
for Carbon Tetrachloride and additional materials supporting the risk
evaluation process in docket ID No. EPA-HQ-OPPT-2016-0733.
    1. 2020 Risk Evaluation.
    In the 2020 Risk Evaluation for Carbon Tetrachloride (Ref. 1), EPA
evaluated risks associated with 15 conditions of use within the
following categories: manufacture (including import), processing,
distribution in commerce, industrial and commercial use, and disposal.
Descriptions of the conditions of use that drive unreasonable risk are
in Unit III.B.1. The 2020 Risk Evaluation for Carbon Tetrachloride
identified significant adverse health effects associated with short-
term and long-term exposure to CTC, specifically cancer and liver
toxicity from chronic inhalation and dermal exposures. Additional risks
associated with liver toxicity and central nervous system effects were
identified for acute inhalation exposures. A further discussion of the
unreasonable risk of CTC is in Unit III.B.3.
    2. 2022 Revised Unreasonable Risk Determination.
    EPA has been revisiting specific aspects of its first ten TSCA
existing chemical risk evaluations, including the 2020 Risk Evaluation
for Carbon Tetrachloride, to ensure that the risk evaluations upon
which risk management decisions are made better align with TSCA's
objective of protecting health and the environment. For CTC, EPA
revised the original unreasonable risk determination based on the 2020
Risk Evaluation for Carbon Tetrachloride and issued a final Revised
Unreasonable Risk Determination for Carbon Tetrachloride in December
2022 (Ref. 3). EPA revised the risk determination for the 2020 Risk
Evaluation for Carbon Tetrachloride pursuant to TSCA section 6(b) and
Executive Order 13990, ``Protecting Public Health and the Environment
and Restoring Science to Tackle the Climate Crisis,'' and other
Administration priorities (Ref. 3). The revisions consisted of making
the risk determination for the whole chemical substance rather than for
individual conditions of use (which resulted in the revised risk
determination superseding the prior ``no unreasonable risk''
determinations and the withdrawal of the associated TSCA section
6(i)(1) ``no unreasonable risk'' order); and clarifying that the risk
determination does not reflect an assumption that all workers are
always provided and appropriately wear PPE (Ref. 3).
    In determining whether CTC presents unreasonable risk under the
conditions of use, EPA considered relevant risk-related factors,
including, but not limited to: the effects of the chemical substance on
health (including cancer and non-cancer risks) and human exposure to
the substance under the conditions of use (including duration,
magnitude and frequency of exposure); the effects of the chemical
substance on the environment and environmental exposure under the
conditions of use; the population exposed (including any potentially
exposed or susceptible subpopulations); the severity of hazard
(including the nature of the hazard, the irreversibility of the
hazard); and uncertainties, including the strengths, and limitations
associated with the information used to calculate the risk estimates.
    EPA determined that CTC presents an unreasonable risk of injury to
health. This unreasonable risk determination is driven by risks to
workers and ONUs (workers who do not directly handle the chemical but
perform work in an area where the chemical is present). EPA did not
identify risks of injury to the environment that drive the unreasonable
risk determination for CTC (Ref. 1). The CTC conditions of use that
drive EPA's determination that the chemical substance poses
unreasonable risk to health are listed in the unreasonable risk
determination (Ref. 3) and in Unit III.B.1., with descriptions to aid
chemical manufacturers, processors, and users in determining how their
particular use or activity would be impacted by the proposed regulatory
provisions. The conditions of use that do not drive the unreasonable
risk for CTC (distribution in commerce and processing as a reactant/
intermediate in reactive ion etching) are also listed in the
unreasonable risk determination (Ref. 3) and in Unit III.B.2. EPA's
proposed regulatory action and primary alternative regulatory action
include prohibitions on the distribution in commerce of CTC for certain
downstream uses, but do not include any restrictions for the processing
as a reactant/intermediate in reactive ion etching.
    3. Fenceline Screening Analysis.
    The 2020 Risk Evaluation for Carbon Tetrachloride excluded the
assessment of certain exposure pathways that were or could be regulated
under another EPA-administered statute (see Section 1.4.3 of the 2020
Risk Evaluation for Carbon Tetrachloride) (Refs. 1 and 3). This
resulted in the surface water, drinking water, and ambient air pathways
for CTC exposure not being assessed for human health risk to the
general population. In June 2021, EPA made a policy announcement on the
path forward for TSCA chemical risk evaluations, indicating that EPA
would, among other things, examine whether the exclusion of certain
exposure pathways from the risk evaluations could lead to a failure to
identify and protect fenceline communities (Ref. 13). EPA then
conducted a screening analysis to identify where there may be potential
risks to people living near the fenceline of facilities releasing CTC.
    In order to assess the potential risk to the general population in
proximity to a facility releasing CTC, EPA developed the TSCA Screening
Level Approach for Assessing Ambient Air and Water Exposures to
Fenceline Communities Version 1.0, which was presented to the SACC in
March 2022, with a report issued by the SACC on May 18, 2022 (Ref. 14).
This analysis and a follow up screening level analysis to consider SACC
feedback are discussed in Unit VI.A.

III. Regulatory Approach

A. Background

    Under TSCA section 6(a), if the Administrator determines through a
TSCA section 6(b) risk evaluation that the manufacture (including
import), processing, distribution in commerce, use, or disposal of a
chemical substance or mixture, or any combination of such activities,
presents an unreasonable risk of injury to health or the environment,
EPA must by rule apply one or more of the following requirements to the
extent necessary so that the chemical substance or mixture no longer
presents such risk.
     Prohibit or otherwise restrict the manufacturing,
processing, or distribution in commerce of the substance or mixture, or
limit the amount of such substance or mixture which may be
manufactured, processed,

or distributed in commerce (TSCA section 6(a)(1)).
     Prohibit or otherwise restrict the manufacturing,
processing, or distribution in commerce of the substance or mixture for
a particular use or above a specific concentration for a particular use
(TSCA section 6(a)(2)).
     Limit the amount of the substance or mixture which may be
manufactured, processed, or distributed in commerce for a particular
use or above a specific concentration for a particular use specified
(TSCA section 6(a)(2)).
     Require clear and adequate minimum warnings and
instructions with respect to the substance or mixture's use,
distribution in commerce, or disposal, or any combination of those
activities, to be marked on or accompanying the substance or mixture
(TSCA section 6(a)(3)).
     Require manufacturers and processors of the substance or
mixture to make and retain certain records, or conduct certain
monitoring or testing (TSCA section 6(a)(4)).
     Prohibit or otherwise regulate any manner or method of
commercial use of the substance or mixture (TSCA section 6(a)(5)).
     Prohibit or otherwise regulate any manner or method of
disposal of the substance or mixture, or any article containing such
substance or mixture, by its manufacturer or processor or by any person
who uses or disposes of it for commercial purposes (TSCA section
6(a)(6)).
     Direct manufacturers or processors of the substance or
mixture to give notice of the unreasonable risk determination to
distributors, certain other persons, and the public, and to replace or
repurchase the substance or mixture (TSCA section 6(a)(7)).
    As described in Unit III.B.4, EPA assessed how the TSCA section
6(a) requirements could be applied to address the unreasonable risk
identified in the 2020 Risk Evaluation for Carbon Tetrachloride and the
final revised unreasonable risk determination, so that CTC no longer
presents such unreasonable risk. EPA's proposed regulatory action and a
primary alternative regulatory action are described in Unit IV. EPA is
requesting public comment on all elements of the proposed regulatory
action and the primary alternative regulatory action and is providing
notice that based on consideration of comments and any new information
submitted to EPA during the comment period on this proposed rule, EPA
may in the final rule modify elements of the proposed regulatory
action. The public should understand that the Agency's consideration of
public comments could result in changes to elements of the proposed and
alternative regulatory actions when this rule is finalized. For
example, elements such as timelines for implementation could be
lengthened or shortened, ECELs could be modified, or the WCPP could
have conditions added or eliminated.
    Under the authority of TSCA section 6(g), EPA may consider granting
a time-limited exemption from a requirement of a TSCA section 6(a) rule
for a specific condition of use if EPA finds that: (1) The specific
condition of use is a critical or essential use for which no
technically and economically feasible, safer alternative is available,
taking into consideration hazard and exposure; (2) compliance with the
requirement, as applied with respect to the specific condition of use,
would significantly disrupt the national economy, national security, or
critical infrastructure; or (3) the specific condition of use of the
chemical substance, as compared to reasonably available alternatives,
provides a substantial benefit to health, the environment, or public
safety. Based on reasonably available information, EPA has analyzed the
need for an exemption and is not proposing to grant an exemption from
the rule requirements at this time. EPA is requesting public comment
regarding the need for exemptions from the rule (and under what
specific circumstances) pursuant to the provisions of TSCA section
6(g). Based on information submitted to EPA during the comment period
on this proposed rule, EPA may issue a supplemental notice proposing an
exemption under TSCA section 6(g). EPA is also requesting comment on,
in lieu of proposing a 6(g) exemption in a separate regulatory action,
whether any elements of the primary alternative regulatory action
should be considered in combination with elements of the proposed
regulatory action as EPA develops the final regulatory action.
    TSCA section 6(c)(2)(C) requires that, in deciding whether to
prohibit or restrict in a manner that substantially prevents a specific
condition of use and in setting an appropriate transition period for
such action, EPA consider, to the extent practicable, whether
technically and economically feasible alternatives that benefit health
or the environment will be reasonably available as a substitute when
the proposed prohibition or restriction takes effect. Unit V.B.
includes more information regarding EPA's consideration of
alternatives, and Unit VI. provides more information on EPA's
considerations more broadly under TSCA section 6(c)(2).
    EPA carried out required consultations as described in this unit
and also considered impacts on children's environmental health as part
of its approach to developing this TSCA section 6 regulatory action.
    1. Consultations.
    EPA conducted consultations and outreach as part of development of
this proposed regulatory action. The Agency held a federalism
consultation from December 17, 2020, until February 17, 2021, as part
of this rulemaking process and pursuant to Executive Order 13132 (see
description in Unit X.E.). During the consultation, EPA met with State
and local officials early in the process of developing the proposed
action in order to receive meaningful and timely input into its
development (Ref. 15). During the consultation, participants and EPA
discussed preemption, EPA's authority under TSCA section 6 to regulate
identified unreasonable risk, and what activities would be potentially
regulated in the proposed rule, and the relationship between TSCA and
existing statutes (Ref. 15). EPA received no written comments as part
of this consultation.
    CTC is not manufactured (including imported), processed,
distributed in commerce, or regulated by Tribal governments. However,
EPA consulted with Tribal officials during the development of this
proposed action (Ref. 16). The Agency held a Tribal consultation from
December 7, 2020, through March 12, 2021, with meetings held on January
6 and 12, 2021. Tribal officials were given the opportunity to
meaningfully interact with EPA risk managers concerning the status of
risk management. During the consultation, EPA discussed risk management
under TSCA section 6(a), findings from the 2020 Risk Evaluation for
Carbon Tetrachloride, types of information that would be helpful to
inform risk management, principles for transparency during the risk
management process, and types of information EPA is seeking from Tribes
(Ref. 16). EPA received no written comments as part of this
consultation.
    In addition to the formal consultations, EPA also conducted
outreach to advocates for communities that might be subject to
disproportionate exposure to CTC, such as minority populations, low-
income populations, and indigenous peoples. EPA's Environmental Justice
(EJ) consultation occurred from February 2, 2021, through April 2, 2021
(Ref. 17). On February 2 and 18, 2021, EPA held public meetings as part
of this consultation. These meetings were held pursuant to and in
compliance with Executive Orders

12898 and 14008. EPA received one written comment following the EJ
meeting, in addition to oral comments provided during the consultation
(Ref. 17). Commenters supported strong regulation of CTC to protect
lower-income communities and workers. In addition, commenters
recommended EPA conduct analysis of additional exposure pathways,
including air and water.
    Units X.C., X.E., X.F. and X.J. provide more information regarding
the consultations.
    2. Other stakeholder consultations.
    In addition to the formal consultations described in Unit X., EPA
attended a Small Business Administration (SBA) Roundtable on December
4, 2020, and held a public webinar on December 10, 2020. At both events
EPA staff provided an overview of the TSCA risk management process and
the findings in the 2020 Risk Evaluation for Carbon Tetrachloride (Ref.
1). Attendees of these meetings were given an opportunity to voice
their concerns on both the risk evaluation and risk management.
    Furthermore, EPA has engaged in discussions with representatives
from different industries, non-governmental organizations, technical
experts, and users of CTC. A list of external meetings held during the
development of this proposed rule is in the docket (Ref. 18); meeting
materials and summaries are also in the docket. The purpose of these
discussions was to hear from users, academics, manufacturers, and
members of the public health community about practices related to
industrial and commercial uses of CTC; public health impacts of CTC;
the importance of CTC in the various uses subject to this proposed
rule; frequently used substitute chemicals or alternative methods;
engineering control measures and personal protective equipment
currently in use or feasibly adoptable; and other risk-reduction
approaches that may have already been adopted or considered for
industrial or commercial uses.
    3. Children's environmental health.
    The Agency's 2021 Policy on Children's Health (Ref. 19) requires
EPA to protect children from environmental exposures by consistently
and explicitly considering early life exposures (from conception,
infancy, early childhood and through adolescence until 21 years of age)
and lifelong health in all human health decisions through identifying
and integrating children's health data and information when conducting
risk assessments. TSCA section 6(b)(4)(A) also requires EPA to conduct
risk evaluations ``to determine whether a chemical substance presents
an unreasonable risk of injury to health or the environment . . .
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.'' Infants, children, and
pregnant women are listed as examples of subpopulations that may be
considered relevant ``potentially exposed or susceptible
subpopulations'' in the TSCA section 3(12) definition of that term. In
addition, TSCA section 6(a) requires EPA to apply one or more risk
management requirements under TSCA section 6(a) so that CTC no longer
presents an unreasonable risk (including unreasonable risk to PESS).
    The 2020 Risk Evaluation for Carbon Tetrachloride considered
impacts on workers ages 17 and older from occupational use from
inhalation and dermal exposures, as applicable. The risk evaluation
considered males (>16 years of age) and females of reproductive age
(>16 years of age) for both dermal and inhalation exposures. While
risks to children (workers 17 through 20 years of age) are not
disproportionate, effects observed in studies include cancer and liver
toxicity from chronic inhalation and dermal exposures and central
nervous system impairment from acute inhalation exposure. The risks
identified would be addressed by both the proposed regulatory action
and primary alternative action described in Unit IV.

B. Regulatory Assessment of Carbon Tetrachloride

    1. Description of conditions of use that drive the unreasonable
risk.
    This unit describes the TSCA conditions of use that drive EPA's
unreasonable risk determination for the chemical substance CTC.
Condition of use descriptions were obtained from EPA sources such as
the 2020 Risk Evaluation for Carbon Tetrachloride and related
documents, and include clarifications based on the CDR use codes, as
well as the Organisation for Economic Co-operation and Development
(OECD) harmonized use codes and feedback from stakeholders regarding
how they describe their uses. For additional description of the
conditions of use, including process descriptions and worker activities
considered in the risk evaluation, see the Problem Formulation of the
2020 Risk Evaluation for Carbon Tetrachloride, the 2020 Risk Evaluation
for Carbon Tetrachloride, and supplemental files (Refs. 1 and 20). EPA
acknowledges that some of the terms used in this unit may also be
defined under other statutes; however, the descriptions in this unit
are intended to provide clarity to the regulated entities subject to
the provisions of this rule under TSCA section 6(a).
    a. Manufacturing.
    i. Domestic manufacture.
    This condition of use refers to making or producing a chemical
substance within the United States (including manufacturing for
export), including the extraction of a component chemical substance
from a previously existing chemical substance or a complex combination
of substances. For purposes of this proposed rule, this condition of
use does not include CTC generated as a byproduct, which was not
evaluated in the 2020 Risk Evaluation for Carbon Tetrachloride (Ref.
1). As explained in Section <IP_ADDRESS> of the 2020 Risk Evaluation for
Carbon Tetrachloride, EPA anticipates that any risks presented by the
presence of CTC generated as byproduct during the manufacture of 1,2-
dichloroethane is being assessed in the risk evaluation for 1,2-
dichloroethane (Ref. 21).
    ii. Import.
    Import refers to the act of causing a chemical substance or mixture
to arrive within the customs territory of the United States. This
condition of use includes loading/unloading and repackaging associated
with import.
    b. Processing.
    i. Processing as a reactant in the production of
hydrochlorofluorocarbon, hydrofluorocarbon, hydrofluoroolefin, and
perchloroethylene.
    CTC serves as a feedstock in the production of another chemical
product via a chemical reaction in which CTC is consumed. Currently,
CTC is used as a reactant to manufacture HCFCs, HFCs, HFOs, and PCE,
which are used in the making of a variety of products including
refrigerants, aerosol propellants, and foam-blowing agents. The
specifics of the reaction process (e.g., use and types of catalysts,
reaction temperature) vary depending on the product being produced;
however, a typical reaction process involves unloading CTC from
containers and feeding into the reaction vessel(s), where CTC either
completely or partially reacts with other raw materials to form the
final product. Following the reaction, the product may be purified to
remove unreacted CTC or other materials if needed.
    ii. Processing: Incorporation into formulation, mixtures, or
reaction products (petrochemicals-derived manufacturing; agricultural
products manufacturing; other basic organic and inorganic chemical
manufacturing).

    Incorporation into formulation, mixture, or reaction products
refers to the process of mixing or blending several raw materials to
obtain a single product or preparation or formulation. CTC is
incorporated into hydrochloric acid (HCl), vinyl chloride, ethylene
dichloride (EDC), chloroform, hafnium tetrachloride, thiophosgene, and
methylene chloride. CTC may be incorporated into various products and
formulations at varying concentrations for further distribution. For
example, CTC may be unloaded from transport containers either directly
into mixing equipment or into an intermediate storage vessel either
manually or through automation via a pumping system. Mixing of
components can occur in either a batch or continuous system. The
mixture that contains CTC may be used as a reactant to manufacture a
chlorinated compound that is subsequently formulated into a product or
a processing aid used to aid in the manufacture of formulated products,
including agricultural chemicals, petrochemicals-derived products, and
any other basic organic and inorganic chemical manufacturing.
    iii. Processing: Repackaging for use as a laboratory chemical.
    Repackaging means the physical transfer of a chemical substance or
mixture, as is, from one container to another container or containers
in preparation for distribution of the chemical substance or mixture in
commerce. Depending on the product, formulation products may be
filtered prior to packaging. Final packaging occurs either through
manual dispensing from transfer lines or through utilization of an
automatic system. Typically, repackaging sites receive the chemical in
bulk containers and transfer the chemical from the bulk container into
another smaller container in preparation for distribution in commerce.
    iv. Processing: Recycling.
    This condition of use refers to the process of treating generated
spent chemical (which would otherwise be disposed of as waste) that is
collected on-site or transported to third-party sites for reclamation/
recycling. Certain spent chemicals, such as CTC, can be restored to a
condition that permits reuse via reclamation/recycling. The
reclamation/recycling process involves an initial vapor recovery (e.g.,
condensation, adsorption, and absorption) or mechanical separation step
(e.g., decanting, filtering, draining, settling and centrifuging)
followed by distillation, purification, and final packaging.
    c. Industrial and commercial use.
    i. Industrial and commercial use as an industrial processing aid in
the manufacture of petrochemical-derived products and agricultural
products.
    A processing aid is a ``chemical that is added to a reaction
mixture to aid in the manufacture or synthesis of another chemical
substance but is not intended to remain in or become part of the
product or product mixture.'' Additionally, processing agents are
intended to improve the processing characteristics or the operation of
process equipment, but not intended to affect the function of a
substance or article created. CTC is used as a processing aid/agent to
aid in the manufacture of formulated products, including agricultural
chemicals and petrochemical-derived products. The condition of use
includes the use of CTC as a process agent in the manufacture of
chlorosulphonated polyolefin; the use of CTC in the manufacture of
stryene butadiene rubber; the use of CTC in the manufacture of
endosulfan (insecticide); the use of CTC in the manufacture of 1-1 Bis
(4-chlorophenyl) 2,2,2-trichloroethanol (dicofol insecticide); and the
use of CTC in the production of tralomethrin (insecticide) (Ref. 1).
    ii. Industrial and commercial use in the manufacture of other basic
chemicals (including chlorinated compounds used in solvents, adhesives,
asphalt, paints and coatings, and elimination of nitrogen trichloride
in the production of chlorine and caustic soda).
    In addition to the other industrial and commercial uses for CTC
outlined in this unit, CTC is used as a processing aid/agent in basic
organic and inorganic chemical manufacturing. CTC may be used as a
processing agent in the manufacturing of chlorinated compounds that are
subsequently used in the formulation of solvents, adhesives, asphalt,
and paints and coatings; in the manufacturing of chlorinated paraffins
(e.g., plasticizer in rubber, paints, adhesives, sealants, plastics),
and chlorinated rubber (e.g., additive in paints, adhesives); and in
the manufacturing of inorganic chlorinated compounds, such as in the
production of chlorine and caustic soda and the recovery of chlorine in
tail gas from the production of chlorine.
    iii. Industrial and commercial use in metal recovery.
    CTC is used as a processing aid or agent to aid in metal recovery.
    iv. Industrial and commercial use as an additive.
    Additives are chemicals combined with a chemical product to enhance
the properties of the product. Additives typically stay mixed within
the finished product and remain unreacted. The risk evaluation examined
the use of CTC as an additive for the manufacture of petrochemical-
derived products and agricultural products. CTC is used as an additive
in fuel and in plastic components used in the automotive industry.
    v. Industrial and commercial use in specialty uses by the U.S.
Department of Defense.
    During the risk evaluation, DoD provided monitoring data for CTC
uses in various processes that include worker activities such as
cleaning and sampling residual metal and ash; destruction of munitions
and storage of resulting liquid waste; and sampling of energetics with
solvent.
    vi. Industrial and commercial use as a laboratory chemical.
    For laboratory uses, CTC is typically received in small containers
and used in small quantities on a laboratory bench in a fume cupboard
or hood. After use, waste CTC is collected and disposed or recycled.
    After the risk evaluation was published, DoD did further analysis
and provided additional information clarifying their current use of CTC
as a laboratory chemical and risk management measures implemented. DoD
provided information on their use of CTC as a laboratory chemical in
chemical weapons destruction, indicating that CTC is used in small
amounts in a confined, laboratory-like setting with advanced
engineering controls. There is no waste CTC generated during this
process.
    d. Disposal.
    This condition of use refers to the process of disposing generated
wasted streams from each of the conditions of use of CTC, that are
collected and transported to third-party sites, such as waste
incineration sites, for disposal.
    e. Terminology in this proposed rule.
    For the purposes of this proposed rulemaking, ``occupational
conditions of use'' refers to the TSCA conditions of use described in
Units III.B.1.a. through d. Although EPA identified both industrial and
commercial uses in the 2020 Risk Evaluation for Carbon Tetrachloride
for purposes of distinguishing exposure scenarios, the Agency clarified
then and clarifies now that EPA interprets the authority over ``any
manner or method of commercial use'' under TSCA section 6(a)(5) to
reach both. In the 2020 Risk Evaluation for Carbon Tetrachloride, EPA
identified and assessed all known, intended, and reasonably foreseen
uses of CTC.
    EPA is not proposing to incorporate the descriptions of known,
intended or reasonably foreseen conditions of uses

of CTC presented in Unit III.B.1.a. through d. into the regulatory text
as definitions because these conditions of use represent those
evaluated in the 2020 Risk Evaluation for Carbon Tetrachloride. EPA
requests comment on whether EPA should promulgate definitions for those
conditions of use evaluated in the 2020 Risk Evaluation for Carbon
Tetrachloride, and, if so, whether the descriptions in this unit are
consistent with the conditions of use evaluated in the 2020 Risk
Evaluation for Carbon Tetrachloride and whether they provide a
sufficient level of detail to improve the clarity and readability of
the regulation if EPA were to promulgate a regulation that contains a
list of all prohibited or otherwise regulated industrial and commercial
conditions of use.
    EPA further notes that this proposed rule does not apply to any
substance excluded from the definition of ``chemical substance'' under
TSCA section 3(2)(B)(ii) through (vi). Those exclusions include, but
are not limited to, any pesticide (as defined by the Federal
Insecticide, Fungicide, and Rodenticide Act) when manufactured,
processed, or distributed in commerce for use as a pesticide; and any
food, food additive, drug, cosmetic, or device, as defined in section
201 of the Federal Food, Drug, and Cosmetic Act (FFDCA), when
manufactured, processed, or distributed in commerce for use as a food,
food additive, drug, cosmetic or device. EPA did not identify any use
of CTC that falls under the authority of the Federal Insecticide,
Fungicide, and Rodenticide Act or the Federal Food, Drug, and Cosmetic
Act (FFDCA).
    2. Description of conditions of use that do not drive the
unreasonable risk.
    As described in the 2020 Risk Evaluation for Carbon Tetrachloride
(Ref. 1) and the 2022 Revised Unreasonable Risk Determination for
Carbon Tetrachloride (Ref. 3), two conditions of use of CTC do not
drive the unreasonable risk determination: distribution in commerce;
and processing as a reactant/intermediate in reactive ion etching,
which is a microfabrication technique used in miniature electronic
component manufacturing that involves using ion bombardment and
reactive gas, such as small quantities of CTC, to selectively etch
wafers.
    As outlined in Unit II.D.2., EPA revised the risk determination for
the 2020 Risk Evaluation for Carbon Tetrachloride pursuant to TSCA
section 6(b) and consistent with Executive Order 13990 and other
Administration priorities (Ref. 3). The 2022 Revised Risk Determination
for Carbon Tetrachloride is based on the whole chemical substance
instead of individual conditions of use. Consistent with the statutory
requirements of TSCA section 6(a), EPA is proposing risk management
regulatory action to the extent necessary so that CTC no longer
presents an unreasonable risk. EPA's proposed risk management action
focuses primarily on the conditions of use that drive the unreasonable
risk (described in Unit III.B.1). However, it should be noted that,
under TSCA section 6(a), EPA is not limited to regulating the specific
activities found to drive unreasonable risk and may select from among a
suite of risk management requirements in TSCA section 6(a) related to
manufacture (including import), processing, distribution in commerce,
commercial use, and disposal as part of its regulatory options to
address the unreasonable risk. EPA's proposed regulatory action and
primary alternative regulatory action, described in Unit IV.A and Unit
IV.B., include prohibitions on the distribution in commerce of CTC for
certain downstream conditions of use, but do not include any
restrictions for the processing of CTC as a reactant/intermediate in
reactive ion etching.
    3. Description of unreasonable risk under the conditions of use.
    EPA has determined that CTC presents an unreasonable risk of injury
to human health under the conditions of use based on cancer and acute
and chronic toxicity for non-cancer effects. As described in the 2020
Risk Evaluation for Carbon Tetrachloride and the July 2022 errata
memorandum correcting risk estimates for acute dermal exposures, EPA
identified cancer and liver toxicity adverse effects from chronic
inhalation and dermal exposures as well as liver toxicity from acute
dermal exposures to CTC (Refs. 1, 2, and 3). Cancer adverse effects
(e.g., liver, pheochromocytoma, neuroblastoma) were identified for
chronic inhalation and dermal exposures. In the 2020 Risk Evaluation
for Carbon Tetrachloride, EPA presented two approaches for the
assessment of carcinogenic risk from CTC: a linear extrapolation
approach for adrenal gland and brain tumors in conjunction with a
threshold approach for assessing risks for liver tumors. The approaches
are based on conclusions on the mode of action for the different cancer
tumors evaluated. The threshold approach used for the risk calculations
for the POD for liver cancer were recommended during the peer review by
the Science Advisory Committee on Chemicals (SACC). For chronic and
acute non-cancer inhalation exposure scenarios to CTC, liver toxicity
due to fatty change in the liver was indicative of cellular damage and
selected as the most sensitive non-cancer endpoint. However, EPA also
identified additional risks associated with other adverse effects
(e.g., immediate and temporary depression of the central nervous
system, kidney toxicity, reproductive and developmental toxicity,
irritation and sensitization, and genetic toxicity) resulting from
acute and chronic exposures (Ref. 1). By targeting liver cancer for
risk management, EPA's action will also eliminate the acute, chronic
non-cancer, and additional cancer risks from CTC (Ref. 9). Unit VI.A.
summarizes the health effects and the magnitude of the exposures.
    To make the unreasonable risk determination for CTC, EPA evaluated
exposures to human receptors including workers and occupational non-
users (ONUs) using reasonably available monitoring and modeling data
for inhalation and dermal exposures. EPA did not evaluate risks to
consumers or bystanders to consumer use because the CPSC banned the use
of CTC in consumer products (excluding unavoidable residues not
exceeding 10 ppm atmospheric concentration) in 1970. After the 2020
Risk Evaluation for Carbon Tetrachloride was completed, EPA conducted a
screening level analysis to assess potential risks from the air and
water pathways to fenceline communities. A discussion of EPA's analysis
and the expected effects of this rulemaking on fenceline communities is
in Unit VI.A.
    For the 2020 Risk Evaluation for Carbon Tetrachloride, EPA
considered PESS and identified groups of individuals with greater
exposure to CTC relative to the general population, including: (1)
workers of either gender (>16 years old), including pregnant women, and
(2) individual workers who do not use CTC but may be indirectly exposed
due to their proximity to the user who is directly handling CTC (ONUs)
(Ref. 1). All PESS are included in the quantitative and qualitative
analyses described in the 2020 Risk Evaluation for Carbon Tetrachloride
and were considered in the determination of unreasonable risk for CTC.
As discussed in Unit II.D and Unit VI.A., the 2020 Risk Evaluation for
Carbon Tetrachloride excluded the air and water exposure pathways to
the general population from the published risk evaluation and may have
caused some risks to be unaccounted for in the risk evaluation. EPA
considers people in the vicinity of facilities releasing CTC and
exposed to CTC through ambient air and

drinking or surface water pathways to constitute a subset of the
general population and categorizes them as fenceline communities; they
may also be considered PESS. See Unit VI.A. for further discussion on
assessing risk to fenceline communities.
    4. Description of TSCA section 6 requirements for risk management.
    EPA considered the TSCA section 6(a) requirements (listed in Unit
III.A.) to identify which ones have the potential to eliminate the
unreasonable risk for CTC.
    As required under TSCA, EPA developed a proposed regulatory action
and one primary alternative regulatory action, which are described in
Units IV.A. and IV.B., respectively. To identify and select a
regulatory action, EPA considered the two routes of exposure driving
the unreasonable risk, inhalation and dermal, and the exposed
populations. For occupational conditions of use (see Unit III.B.1.),
EPA considered how it could directly regulate manufacturing (including
import), processing, distribution in commerce, industrial and
commercial use, or disposal to address the unreasonable risk.
    As required by TSCA section 6(c)(2), EPA considered several
factors, in addition to identified unreasonable risk, when selecting
among possible TSCA section 6(a) requirements. To the extent
practicable, EPA factored into its decisions: (i) The effects of CTC on
health and the magnitude of exposure of human beings to CTC, (ii) the
effects of CTC on the environment and the magnitude of exposure of the
environment to CTC, (iii) the benefits of CTC for various uses, and
(iv) the reasonably ascertainable economic consequences of the rule. In
evaluating the reasonably ascertainable economic consequences of the
rule, EPA considered: (i) The likely effect of the rule on the national
economy, small business, technological innovation, the environment, and
public health, (ii) the costs and benefits of the proposed regulatory
action and of the primary alternative regulatory action considered, and
(iii) the cost effectiveness of the proposed regulatory action and of
the primary alternative regulatory action considered. See Unit VI. for
further discussion related to TSCA section 6(c)(2)(A) considerations,
including the statement of effects of the proposed rule with respect to
these considerations.
    EPA also considered the regulatory authorities under statutes
administered by other agencies such as OSHA's implementation of the OSH
Act, as well as other EPA-administered statutes to examine: (1) whether
there are opportunities for all or part of this risk management action
to be addressed under other statutes, such that a referral may be
warranted under TSCA sections 9(a) or 9(b); or (2) whether TSCA section
6(a) regulation could include alignment of requirements and definitions
in and under existing statutes and regulations to minimize confusion to
the regulated entities and the general public.
    In addition, EPA followed other TSCA requirements such as
considering the availability of alternatives when contemplating a
prohibition or a substantial restriction (TSCA section 6(c)(2)(C), as
outlined in Unit V.B.), and setting proposed compliance dates in
accordance with the requirements in TSCA section 6(d)(1)(B) (described
in the proposed and alternative regulatory action in Units IV.A and
IV.B.).
    To the extent information was reasonably available, EPA considered
pollution prevention strategies and the hierarchy of controls adopted
by OSHA and NIOSH when selecting regulatory actions, with the goal of
identifying risk management control methods that are permanent,
feasible, and effective. EPA also considered how to address the
unreasonable risk while providing flexibility to the regulated entity,
where appropriate, and took into account the information presented in
the 2020 Risk Evaluation for Carbon Tetrachloride, as well as
additional input from stakeholders (as described in Unit III.A.) and
anticipated compliance strategies from regulated entities.
    Taken together, these considerations led EPA to the proposed
regulatory action and primary alternative regulatory action described
in Unit IV. Additional details related to how the requirements in this
unit were incorporated into development of those actions are in Unit V.

IV. Proposed Regulatory and Alternative Regulatory Actions

    This unit describes the proposed regulatory action by EPA so that
CTC will no longer present an unreasonable risk of injury to health. In
addition, as indicated by TSCA section 6(c)(2)(A), EPA must consider
the costs and benefits and the cost-effectiveness of the proposed
regulatory action and one or more primary alternative regulatory
actions. In the case of CTC, the proposed regulatory action is
described in Unit IV.A. and the primary alternative regulatory action
considered is described in Unit IV.B. This unit also describes the
proposed compliance timeframes. The rationale for the proposed and
alternative regulatory actions and associated compliance timeframes are
discussed in this unit and in more detail in Unit V.A.

A. Proposed Regulatory Action

    EPA is proposing under TSCA section 6(a) to: (1) Require a WCPP,
including an ECEL and DDCC requirements, for the manufacturing
(including import) of CTC and for other conditions of use (accounting
for essentially all of the production volume of CTC manufactured
annually) that occur in industrial settings or in tightly controlled,
closed systems, where monitoring data submitted for the 2020 Risk
Evaluation for Carbon Tetrachloride indicate values below the ECEL, or
where technically and economically feasible safer alternatives may not
be reasonably available, or where industry has indicated a reliance on
CTC and EPA has found that an ECEL and DDCC requirements would address
the unreasonable risk; (2) Require prescriptive controls for one
condition of use, industrial and commercial use as a laboratory
chemical, where codifying existing practices of use of a fume hood for
all laboratory uses (and for DoD's use of CTC as a laboratory chemical
codifying advanced engineering controls) and requiring dermal PPE would
address the unreasonable risk; and (3) Prohibit certain processing,
industrial, and commercial conditions of use and the manufacture,
processing, and distribution for those uses, which the Agency
understands have already been phased out. EPA is also proposing to
require recordkeeping and to require manufacturers (including
importers), processors, and distributors of CTC for any use to provide
downstream notification of regulatory requirements. As the manufacture
and processing of CTC presents an unreasonable risk to health in the
United States, the manufacture and processing of CTC for export would
also be prohibited or restricted in accordance with TSCA section
12(a)(2).
    1. Workplace Chemical Protection Program (WCPP) for certain
manufacturing, processing, industrial and commercial uses, and
disposal.
    a. Overview.
    As described in Unit III.B.4, under TSCA section 6(a), EPA is
required to issue a regulation applying one or more of the TSCA section
6(a) requirements to the extent necessary so that the unreasonable risk
of injury to human health or the environment from a chemical substance
is no longer present. The TSCA section 6(a) requirements provide EPA
the authority to limit or prohibit a number of activities, including,
but not limited to, restricting

or regulating the manufacture, processing, distribution in commerce,
commercial use, or disposal of the chemical substance. Given this
statutory authority, EPA may find it appropriate in certain
circumstances to propose a WCPP for certain occupational conditions of
use (i.e., manufacturing, processing, distribution in commerce,
industrial and commercial use, or disposal). This unit describes the
proposed WCPP, which consists of an ECEL and DDCC requirements, and
ancillary provisions necessary for successful implementation such as
periodic monitoring, consideration of the hierarchy of controls, an
exposure control plan, and respirators and dermal PPE programs (if
applicable). Under a WCPP, owners or operators would have some
flexibility, within the parameters outlined in this unit, regarding how
they prevent exceedances of the identified EPA exposure limit
thresholds or prevent direct dermal contact. In the case of CTC,
meeting the EPA exposure limits and implementing the DDCC requirements
for certain occupational conditions of use would address the
unreasonable risk to potentially exposed persons from inhalation and
dermal exposure.
    EPA uses the term ``potentially exposed person'' in this unit and
in the regulatory text to include workers, occupational non-users,
employees, independent contractors, employers, and all other persons in
the work area where CTC is present and who may be exposed to CTC under
the conditions of use for which a WCPP would apply. EPA's intention is
to require a comprehensive WCPP that would address the unreasonable
risk from CTC to potentially exposed persons directly handling the
chemical or in the work area where the chemical is being used.
Similarly, the 2020 Risk Evaluation for Carbon Tetrachloride did not
distinguish between employers, contractors, or other legal entities or
businesses that manufacture, process, distribute in commerce, use, or
dispose of CTC. For this reason, EPA uses the term ``owner or
operator'' to describe the entity responsible for implementing the WCPP
in any workplace where an applicable condition of use described in
Units III.B.1.a. through d. and subject to the WCPP is occurring. The
term includes any person who owns, leases, operates, controls, or
supervises such a workplace.
    EPA is proposing a WCPP for manufacturing (including import) of CTC
and the following other conditions of use which account for essentially
all of the production volume of CTC manufactured annually:
     Processing as a reactant in the production of HCFCs, HFCs,
HFOs, and PCE;
     Processing: Incorporation into a formulation, mixture or
reaction product in agricultural products manufacturing and other basic
organic and inorganic chemical manufacturing;
     Processing: Repackaging for use as a laboratory chemical;
     Processing: Recycling;
     Industrial and commercial use as an industrial processing
aid in the manufacture of agricultural products;
     Industrial and commercial use in the elimination of
nitrogen trichloride in the production of chlorine and caustic soda;
and
     Disposal.
    EPA recognizes that CTC may be a minor input in the production of
HCFCs, HFCs, and PCE. EPA understands that CTC may still be used to
manufacture HCFCs and HFCs, including HFC-245fa, HFC-365mfc, and HFC-
236fa; however, more recently industry has expressed particular
reliance on CTC for the manufacture of HFOs. In addition, CTC may be a
minor input when recycled to make additional PCE. Therefore, EPA is
soliciting comments on the expected need for a WCPP with an ECEL and
DDCC requirements for these uses, whether prescriptive controls,
including respirators and dermal PPE, should be required for these uses
(as outlined in Unit IV.B.1. in the primary alternative regulatory
action), or whether the Agency should instead consider prohibiting
these uses because they will likely phase out, including timing for
such expected phaseout.
    EPA is proposing to exclude from WCPP requirements for
manufacturers those workplaces that manufacture CTC solely as a
byproduct. Section <IP_ADDRESS> of the 2020 Risk Evaluation for Carbon
Tetrachloride stated that EPA excluded from the scope of the risk
evaluation conditions of use associated with CTC generated as a
byproduct (Ref. 1). In addition, EPA is assessing the manufacture of
CTC as a byproduct during the manufacture of 1,2-dichloroethane in the
risk evaluation for 1,2-dichloroethane (Ref. 21).
    b. Workplace Chemical Protection Program (WCPP) requirements.
    i. Existing Chemical Exposure Limit (ECEL) and ECEL Action Level.
    To reduce exposures in the workplace and address the unreasonable
risk of injury to health resulting from inhalation exposures to CTC
identified under the conditions of use in the TSCA Risk Evaluation, EPA
is proposing an ECEL of 0.03 parts per million (ppm) (0.2 mg/m\3\) for
inhalation exposures to CTC as an 8-hour time-weighted average (TWA)
and, based on industrial hygiene practices, owners and operators may
implement various controls to consider different lengths of exposure at
the workplace. This ECEL is based on the POD for liver cancer. The ECEL
memo includes linear risk calculations for adrenal gland tumors in the
equation for ``Cancer risk for other tumor types (e.g., adrenal glands)
at the ECEL,'' showing that the ECEL is protective of all tumor types,
including adrenal gland and brain tumors (Ref. 9). EPA has determined,
as a matter of risk management policy, that ensuring exposures remain
at or below the ECEL would eliminate the contribution to the
unreasonable risk of injury to health for CTC resulting from inhalation
exposures in an occupational setting. If ambient exposures are kept at
or below the 8-hour TWA ECEL of 0.03 ppm, EPA expects that a
potentially exposed person in the workplace would also be protected
against all non-cancer effects resulting from occupational inhalation
exposures, as well as excess risk of cancer (Ref. 9).
    EPA is also proposing to establish an ECEL action level of 0.02 ppm
as an 8-hour TWA for CTC. Air concentrations at or above the action
level would trigger more frequent periodic monitoring of exposures to
CTC, as described in this unit. EPA is proposing to adopt the action
level approach in implementing the TSCA ECEL, similar to the action
level approach utilized by OSHA in most of their standards. As
explained by OSHA, due to the variable nature of employee exposures,
compliance with an action level (which OSHA generally establishes at
half the 8-hour TWA exposure limit) provides employers with greater
assurance that their employees will not be exposed to concentrations
above the PELs (62 FR 1494, January 10, 1997). EPA agrees with this
reasoning and, like OSHA, expects the inclusion of an ECEL action level
at a value below the ECEL will stimulate innovation within industry to
reduce exposures to levels below the action level. In this case EPA is
proposing an action level for CTC of 0.02 ppm which is two-thirds of
the ECEL rather than 0.015 ppm (the value that represents half the
ECEL). Because EPA's understanding of current industry practices is
that it may be more feasible for owners or operators to measure
concentrations with values closer to the ECEL, such as within 10% of
the ECEL, EPA is soliciting comment regarding an ECEL action level that
is two-thirds the ECEL, including considerations for a different ECEL
action level value, and any associated or alternative provisions

related to the ECEL action level since the ECEL is significantly lower
than the OSHA PEL.
    EPA acknowledges that the values of the ECEL and the ECEL action
level outlined in this unit may mean that some entities that are
currently in compliance with OSHA requirements would have to do more in
order to achieve compliance with the requirements being proposed in
this action. It may be necessary to implement engineering controls to
reduce exposures to the extent feasible, increase the frequency of
periodic exposure monitoring (Unit IV.A.1.b.ii.), implement respiratory
protection (Unit IV.A.1.e.i.), and provide notification of monitoring
results (Unit IV.A.1.g.), and EPA is soliciting comment on these
actions and the cost associated with them. Nevertheless, as discussed
further in Unit V.A.1.c., based on monitoring data submitted by
industry for the 2020 Risk Evaluation for Carbon Tetrachloride
indicating industry was already achieving values below the ECEL, EPA
has confidence that requirements to meet an ECEL can be implemented in
highly standardized and industrialized settings, including those where
CTC is manufactured, processed, and used (EPA-HQ-OPPT-2016-0733-0101).
    Each owner or operator of a workplace where these conditions of use
occur would be responsible for compliance with the ECEL and the
associated requirements. EPA's description for how the requirements
related to an ECEL would address the unreasonable risk resulting from
inhalation exposures and the rationale for this regulatory approach is
outlined in Units III.B.3 and V.A. The proposed requirements of the
WCPP ECEL are not applicable to owners and operators of workplaces
where manufacturing and processing solely for the industrial and
commercial conditions of use that EPA is proposing to prohibit occurs,
as described Unit IV.A.3.
    In summary, EPA is proposing that each owner or operator of a
workplace subject to the ECEL must ensure that no person is exposed to
airborne concentration of CTC in excess of 0.03 ppm (0.2 mg/m\3\) as an
8-hour TWA (ECEL), with an action level identified as 0.02 ppm (0.13
mg/m\3\) as an 8-hour TWA (ECEL action level). For conditions of use
for which the requirements to meet an ECEL are being proposed, EPA
expects that the regulated community can measure CTC at the ECEL and
ECEL action level because they are above the level of detection for air
sampling analytical methods for CTC, which are as low as 4 micrograms
per sample (Ref. 9). Nevertheless, EPA understands that the regulated
community may have difficulty measuring at or below the ECEL
consistently over an entire work shift (Ref. 22). Therefore, EPA is
requesting comment regarding the amount of time, if any, it would take
the regulated community to develop a method to measure at or below the
ECEL over an entire work shift. EPA is interested in what levels of
detection are possible over an entire work shift based on existing
monitoring methods, justification for the timeframe of the specific
steps needed to develop a more sensitive monitoring method, cost
associated with a more sensitive monitoring method, and any additional
detailed information related to establishing a monitoring program to
reliably measure CTC at or below the ECEL.
    EPA expects that many workplaces already have stringent controls in
place that reduce exposures to CTC; for some workplaces, EPA
understands that these existing controls may already reduce CTC air
concentration levels to levels near or below the ECEL. As noted
previously in this unit, EPA expects that, if inhalation exposures for
affected occupational conditions of use are kept at or below the ECEL,
potentially exposed persons reasonably likely to be exposed in the
workplace would be protected from unreasonable risk. EPA is also
proposing to require owners or operators to comply with additional
requirements under the WCPP that would be needed to ensure successful
implementation of the ECEL.
    ii. Monitoring Requirements for the ECEL.
    (A) Overview.
    Monitoring requirements are a key component of implementing EPA's
proposed ECEL. Initial exposure monitoring for CTC is critical for
establishing a baseline of exposure for potentially exposed persons;
similarly, periodic exposure monitoring ensures continued compliance so
that potentially exposed persons in the workplace are not exposed to
levels that would result in an unreasonable risk of injury. Periodic
exposure monitoring frequency could change if certain conditions are
met, which are described in this unit. Additionally, in some cases, a
change in workplace conditions with the potential to impact exposure
levels would warrant additional exposure monitoring, which is also
described. This unit also describes the proposed monitoring records
required.
    (B) Initial exposure monitoring.
    Under the proposed regulation, each owner or operator of a
workplace where any condition of use listed earlier in this unit is
occurring would be required to perform initial exposure monitoring for
all persons who may be exposed to CTC to establish a baseline of the
magnitude of exposure within 180 days after date of publication of the
final rule in the Federal Register or within 30 days of the
introduction of CTC into the workplace, whichever is later. Initial
exposure monitoring would notify owner or operators of the magnitude of
exposures to their potentially exposed persons with respect to their
unique work conditions and environments. The results from the initial
exposure monitoring would determine the frequency of future periodic
exposure monitoring and whether additional exposure controls are
necessary (such as engineering controls, administrative controls, and/
or respiratory protection), and whether the owner or operator would
need to demarcate a regulated area as described in this unit.
    Where CTC is present in the workplace, each owner or operator would
be required to determine each potentially exposed person's exposure by
either taking a personal breathing zone air sample of each potentially
exposed person or taking personal breathing zone air samples that are
representative of each potentially exposed person's exposure performing
the same or substantially similar operations in each work shift, in
each job classification, in each work area (hereinafter identified as
an ``exposure group''). Representative 8-hour TWA exposures must be
determined based on one or more samples representing full-shift
exposures for each shift for each person in each job classification in
each work area. Monitoring samples must be taken when and where the
operating conditions are best representative of each potentially
exposed person's full-shift exposures. EPA expects that owners and
operators would attempt to monitor exposures for all of the tasks
during the same timeframe; however, EPA understands that certain tasks
occur less frequently, and EPA is soliciting comments regarding the
timing of the initial exposure monitoring so that it is representative
of all tasks involving CTC where exposures may approach the ECEL. If
the owner or operator chooses a representative sample, such sampling
must include persons that are the closest to the source of CTC, so that
the monitoring results are representative of the most highly exposed
persons in the workplace. EPA is also soliciting comments regarding use
of area source monitoring instead of

personal breathing zone as a representative sample of exposures.
    EPA also recognizes that some entities may already have exposure
monitoring data. If the owner or operator has monitoring data conducted
within five years prior to the effective date of the final rule and the
monitoring satisfies all other proposed requirements, including the
requirement that the data represents the highest CTC exposures likely
to occur under reasonably foreseeable conditions of use, the owner or
operator may rely on such earlier monitoring results for the initial
baseline monitoring sample.
    (C) Periodic exposure monitoring.
    Based on the results of the initial exposure monitoring, EPA is
proposing to require each owner or operator to conduct, for those
exposure groups that result in the following airborne concentration
levels, the following periodic monitoring:
     If all samples taken during the initial exposure
monitoring reveal a concentration below the ECEL action level (0.02 ppm
8-hr TWA), the owner or operator must repeat the periodic exposure
monitoring at least once every five years.
     If the most recent exposure monitoring reveals a
concentration above the ECEL (0.03 ppm 8-hr TWA), the owner or operator
must repeat the periodic exposure monitoring at least every 3 months.
     If the most recent exposure monitoring reveals a
concentration at or above the ECEL action level (0.02 ppm 8-hr TWA) but
at or below the ECEL (0.03 ppm 8-hr TWA), the owner or operator must
repeat the periodic exposure monitoring at least every 6 months.
     If the most recent (non-initial) exposure monitoring
indicates that airborne exposure is below the ECEL action level, the
owners or operators must repeat such monitoring within 6 months of the
most recent monitoring until two consecutive monitoring measurements,
taken at least seven days apart, are below the ECEL action level (<0.02
ppm 8-hour TWA), at which time the owner or operator must repeat the
periodic exposure monitoring at least once every 5 years.
    Additionally, in instances where an owner or operator does not
manufacture, process, use, or dispose of CTC for a condition of use for
which the restrictions would be in place over the entirety of time
since the last required periodic exposure monitoring event, EPA is
proposing that the owner or operator may forgo the next periodic
exposure monitoring event. However, documentation of cessation of use
of CTC must be maintained and periodic exposure monitoring would be
required to resume should the condition of use restart.
    The proposed periodic exposure monitoring requirements are also
outlined in Table 1. EPA requests comment on the timeframes for
periodic exposure monitoring outlined in this unit. EPA may finalize
significantly shorter, longer or different timeframes based on
consideration of public comments.

                Table 1--Periodic Monitoring Requirements
------------------------------------------------------------------------
                                           Periodic exposure monitoring
      Air concentration condition                  requirement
------------------------------------------------------------------------
If all initial exposure monitoring is    Periodic exposure monitoring is
 below the ECEL action level (<0.02 ppm   required at least once every
 8-hour TWA).                             five years.
If the most recent exposure monitoring   Periodic exposure monitoring is
 indicates that airborne exposure is      required within 3 months of
 above the ECEL (>0.03 ppm 8-hour TWA).   the most recent exposure
                                          monitoring.
If the most recent exposure monitoring   Periodic exposure monitoring is
 indicates that airborne exposure is at   required within 6 months of
 or above the ECEL action level but at    the most recent exposure
 or below the ECEL (>=0.02 ppm 8-hour     monitoring.
 TWA, <=0.03 ppm 8-hour TWA).
If the two most recent (non-initial)     Periodic exposure monitoring is
 exposure monitoring measurements,        required within 5 years of the
 taken at least seven days apart within   most recent exposure
 a 6-month period, indicate exposure is   monitoring.
 below the ECEL action level (<0.02 ppm
 8-hour TWA).
If the owner or operator engages in a    The owner or operator may forgo
 condition of use for which WCPP ECEL     the next periodic monitoring
 would be required but does not           event. However, documentation
 manufacture, process, use, or dispose    of cessation of use of CTC is
 of CTC in that condition of use over     required; and periodic
 the entirety of time since the last      monitoring would be required
 required monitoring event.               when the owner or operator
                                          resumes the condition of use.
------------------------------------------------------------------------

    (D) Additional exposure monitoring.
    In addition to the initial and periodic exposure monitoring, EPA is
proposing that each owner or operator conduct additional exposure
monitoring whenever: (i) A change in the production, process, control
equipment, personnel, work practices may reasonably be expected to
result in new or additional exposures at or above the ECEL action
level, or (ii) the owner or operator has any reason to believe that new
or additional exposures at or above the ECEL action level have
occurred. In the event of start-up, shutdown, malfunctions or other
breakdowns that may lead to exposure to any person in the workplace,
EPA is proposing that each owner or operator must conduct additional
exposure monitoring (using personal breathing zone sampling) after the
cleanup, repair or remedial action to ensure that exposures are below
the ECEL or the ECEL action level. An additional exposure monitoring
event may result in an increased frequency of periodic exposure
monitoring. For example, if the initial exposure monitoring results
from a workplace are above the ECEL action level, but below the ECEL,
periodic exposure monitoring is required every 6 months. If additional
exposure monitoring is performed because increased exposures are
suspected, and the results are above the ECEL, subsequent periodic
exposure monitoring would have to be performed every 3 months. The
required additional exposure monitoring should not delay implementation
of any necessary cleanup or other remedial action to reduce the
exposures to persons in the workplace. The additional exposure
monitoring is also included in Table 1. EPA requests comment on the
timeframes and frequency for additional exposure monitoring outlined in
this unit.
    (E) Other exposure monitoring requirements.
    For each exposure monitoring event, EPA is proposing to require
that owners or operators ensure that their analytical methods be
accurate, to a confidence level of 95 percent, to within plus or minus
25 percent for airborne concentrations of CTC at an appropriate level
of detection for the ECEL and ECEL action level. Also, EPA is proposing
to require use of appropriate sampling and analytical methods used to
determine CTC exposure, including as relevant: (A) Use of an analytical

method already approved by EPA, OSHA or NIOSH, or another analytical
method that has been demonstrated to meet the proposed accuracy
requirement at an appropriate level of detection for the ECEL and ECEL
action level; (B) Compliance with the Good Laboratory Practice
Standards at 40 CFR part 792. Also, EPA is proposing to require owners
and operators to re-monitor within 15 working days after receipt of the
results of any exposure monitoring when results indicate non-detect or
air monitoring equipment malfunction, unless an Environmental
Professional as defined at 40 CFR 312.10 or a Certified Industrial
Hygienist reviews the exposure monitoring results and determines that
re-monitoring is not necessary.
    EPA is also proposing to require that each owner or operator
maintain exposure monitoring records that include the following