these uses. Based on information received from DoD, a 10-year timeframe
for this exemption would prevent disruption of national security and
allow critical infrastructure priorities to be met.
iii. Analysis of the Need for TSCA Section 6(g)(1)(A) Exemption of TCE
for Laboratory Use That for Essential Laboratory Activities
    During the analysis for this rulemaking of the uses of TCE, EPA
agrees that it is necessary to allow the continued use of TCE for
laboratory use for essential laboratory activities (this use is within
the condition of use ``Industrial and commercial use of TCE in hoof
polish; gun scrubber; pepper spray; and other miscellaneous industrial
and commercial uses,'' described in Unit III.B.1.c.xx.). Under
essential laboratory activities, EPA includes chemical analysis,
chemical synthesis, extracting and purifying other chemicals, or
dissolving other substances. Additionally, EPA includes as an essential
laboratory activity research and development for new technologies
related to monitoring and remediation for cleanup activities

related to TCE contamination and for new analytical methods for
exposure monitoring (e.g., for the ECEL).
    Under TSCA section 6(g)(1)(A), EPA determined that TCE use as a
laboratory chemical for essential laboratory activities is a critical
and essential use with no technically and economically available
substitutes. The use of TCE in laboratory use for essential laboratory
activities is critical for ongoing Federal, state, and local government
cleanup projects, in which it is necessary to use TCE as a laboratory
chemical for the analysis of TCE-contaminated soil, air, and water
samples. In these projects which are specific to TCE, the continued use
of TCE in laboratory settings for chemical analysis when applied to
cleanup and exposure monitoring is critical to efforts to improve
health, the environment, and public safety and is without a technically
available substitute. Additionally, industrial laboratory analysis is
essential in monitoring for the presence of TCE for the adequate
reduction of overall exposure to TCE in alignment with the hierarchy of
controls. In order to accurately conduct exposure monitoring of TCE to
implement the WCPP for the uses with longer timeframes, industrial and
commercial use of TCE as a laboratory chemical to provide for the
chemical analysis of samples is critical and essential and without a
technical alternative. A 50-year timeframe for the continued use of TCE
for uses in a laboratory for chemical analysis would allow a sufficient
time for TCE remediation to occur at most identified clean-up sites, as
well as sites not yet identified. EPA also proposes to include in this
exemption the use by NASA of TCE in essential laboratory activities as
a laboratory reagent, calibration standard, and for dissolving other
substances (Ref. 56). Following interagency consultation with NASA, EPA
understands NASA's critical use of TCE in laboratories to include
sample preparation and equipment calibration related to the search for
chlorinated hydrocarbons on Mars, calibration of gas mixture used in
identification of contaminants in breathing air in human-rated space
and aerospace systems, and preparation of quality assurance samples for
groundwater analysis. EPA is also aware of an additional critical use
of TCE in laboratories by NASA to dissolve substances, such as for wax
removal from infrared sensors. The wax is applied to protect the
sensors during the development of infrared detectors incorporated into
specialty instruments. TCE is used to remove the wax, and, unlike other
solvents, has not been found to damage other delicate components of the
infrared sensors.
    As an example of this use, EPA notes that the devices that require
this kind of wax removal are built in the Detector Development Lab,
which is an International Standards Organization 5 cleanroom dedicated
to fabrication of detectors (including infra-red). The lab utilizes
semiconductor like processes to create these devices in silicon wafers
or similar substrates, through build up or removal of layers toward
meeting NASA missions. Detectors and devices are built in the lab that
are not typically found in industry yet are needed to meet NASA
requirements. The devices built tend to be unique, one-of-a-kind
devices created using equally unique and highly specialized processes.
One of these processes uses TCE. Part of device fabrication requires
building up or removing material from both sides of the wafer. To do
so, while protecting one side, a sacrificial substrate is commonly
adhered to the silicon substrate using a wax material as glue. In many
cases, when the process is complete, the wax is dissolved away to
remove the sacrificial substrate. Common waxes that achieve this
process are readily dissolved in a polar solvent such as acetone. The
build-up or removal of material is done in a manner to create very
specific patterns with each layer. These patterns are transferred to
the substrate using a polymer material called photoresist. Once the
pattern transfer is complete the photoresist is removed using acetone
or other means.
    In the case of creating certain types of infra-red detectors, there
is a need to embed a photoresist pattern within the wax layer when
gluing a sacrificial substrate to the silicon wafer. The requirement is
that the patterned resist remain intact after dissolving the wax. Using
solvents such as acetone would simultaneously dissolve the resist
pattern or in the case of some solvents deform or weaken the
photoresist beyond rendering it unusable. TCE is the only product
identified that can perform this process. Specifically, TCE is able to
dissolve the wax layer and leave the patterned resist layer
uncompromised. The use of TCE is solely for dissolving material and is
always used in an exhausted hood in the laboratory. Each hood is
inspected yearly by an on-site Industrial Hygiene Office to ensure
proper airflow and operation. The hood has a local alarm for airflow
that is tested daily for operation. The clean room has vertical laminar
air flow, pushing air into the exhausted hoods as air is pulled by the
exhaust fans. The room is maintained at a positive pressure of 0.08
inches on water column. For added exposure reduction, the laboratory is
equipped with a separate emergency exhaust fan which, if activated,
creates a negative pressure in the laboratory. All potentially exposed
persons are provided a full set of PPE that includes apron with arm
guards, face shield, safety glasses, standard issue nitrile gloves and
chemical gloves rated for chlorinated solvents.
    The process consists of the following steps: First, the wafer is
soaked in 200-2000 mL of TCE (volume dependent on wafer size). When the
wax is fully dissolved, the wafer is transferred to a second (fresh)
TCE container of 200-2000mL and soaked for several minutes. Then, the
effluent is rinsed with de-ionized water and the waste TCE is captured
in waste containers for disposal by an on-site Environmental Group.
This process is conducted over the span of approximately one week and
is required an average of 3 times per year. When the process is
complete all chemicals are disposed of or stored in screw capped
bottles within an exhausted enclosure. Based on the information
available to EPA, EPA is including the use of TCE in laboratories by
NASA to dissolve substances as part of the proposed exemption for use
of TCE in laboratories for essential laboratory activities. In
addition, based on the information provided by NASA and other Federal
agencies, EPA has considered and is including in this proposal an
exemption for additional research and development activities and test
and evaluation method activities, and similar laboratory activities,
conducted by Federal agencies and their contractors, provided the use
is essential to the agency's mission. As described more fully in Unit
V.A.3.a.vi., for example, NASA's mission requires that it operate at
the cutting edge of science, in environments that are hostile to life,
especially human life. While NASA is skilled at addressing problems
presented by these environments, EPA is concerned that the proposed
limits on this laboratory use exemption in general would negatively
affect NASA's ability to respond to issues that arise in spaceflight,
particularly human spaceflight. Similarly, EPA believes that the DoD's
unique mission requires additional flexibilities for research and
development in order to maintain military readiness at all times.
    It should be noted that the use of TCE in laboratory settings for
testing asphalt would not be included in this TSCA section 6(g)
exemption because it is not critical nor essential, and because
alternative testing methods exist,

including the Nuclear Asphalt Content Gauge and the Ignition Method
(Ref. 57). EPA requests comment on whether 50 years is a reasonable
timeframe for the TSCA section 6(g) exemption for the industrial and
commercial use of TCE in laboratory use essential for chemical
analysis. Specifically, EPA requests comment on the anticipated
duration of TCE cleanup projects, and whether there will be projects
that continue and require the use of TCE as a laboratory chemical for
the analysis of contaminated soil, air, and water samples past 50
years. Additionally, EPA requests comment on if the exemption for
laboratory use of TCE should include research and development purposes
for objectives broader than cleanup activities or exposure monitoring,
such research into TCE alternatives, whether these broader objectives
should be limited to Federal agencies and their contractors or expanded
to include others, and whether a shorter time period, such as 10 years,
should be imposed on these broader research and development activities.
iv. Analysis of the Need for a TSCA Section 6(g)(1)(A) Exemption for
Disposal of TCE to Industrial Pre-Treatment, Industrial Treatment, or
Publicly Owned Treatment Works for the Purposes of Cleanup Projects of
TCE-Contaminated Groundwater and Other Wastewater
    EPA has conducted an analysis of the application of this rulemaking
and found that the disposal of TCE to industrial pre-treatment,
industrial treatment, or publicly owned treatment works for the
purposes of cleanup projects of TCE-contaminated groundwater and other
wastewater should be permitted to continue for some period of time to
avoid adverse impacts on these important remediation projects.
    TCE is a contaminant of concern in a significant number of cleanup
sites that are managed under the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA), also known as Superfund
sites, as well as under the Resource Conservation and Recovery Act
(RCRA) and state programs authorized under RCRA. The remediation of
these sites, including the removal and treatment of TCE-contaminated
groundwater, is critical to EPA's mission to protect human health and
the environment. The disposal of wastewater that contains TCE to
industrial pre-treatment, industrial treatment, or publicly owned
treatment works is an important method used in these cleanup efforts.
In EPA's analysis of this rulemaking, EPA determined that at many
contaminated sites, TCE-contaminated wastewater is pumped out of the
ground and either sent to offsite industrial treatment or publicly
owned treatment works. EPA acknowledges that the cleanup of these sites
is vital work in which the disposal of TCE is a critical or essential
use for which no technically and economically feasible safer
alternative is available that must continue under CERCLA, RCRA,
authorized state programs, and/or orders or permits issued under those
authorities. Taking into consideration hazards and exposure, a
prohibition on disposal without this exemption could result in
prolonged exposure to TCE-contaminated groundwater for affected
communities. EPA is concerned that eliminating a common disposal method
for TCE-contaminated groundwater would be a significant burden on these
cleanups and would likely slow the pace of remediation at the numerous
sites where TCE-contaminated groundwater is a problem. EPA also
understands that there are other sites where TCE-contaminated
groundwater is being addressed under the authority of other federal
environmental laws or state and local government authorities, including
at sites that are currently implementing remedies selected through
relevant statutory and regulatory processes, and the impact of a
prohibition on an important disposal method is expected to be similar.
EPA therefore is proposing a 50-year exemption from the prohibition on
disposal of TCE by industrial pre-treatment, industrial treatment, or
publicly owned treatment works for cleanup projects undertaken under
the authority of CERCLA, RCRA, or other federal, state, or local
government environmental laws, regulations, or requirements.
    A 50-year timeframe for the continued disposal of TCE to industrial
pre-treatment, industrial treatment, or publicly owned treatment works
for the purposes of federal, state, and local government cleanup
projects would allow a sufficient time for TCE remediation to occur at
most sites. Additionally, the 50-year timeframe aligns with the
proposed 50-year time-limited TSCA section 6(g)(1)(A) exemption for
industrial and commercial use of TCE as a laboratory chemical in
essential laboratory activities, which is also intended to support
cleanup operations through allowing for the analysis of samples. EPA
requests comment on whether 50 years is a reasonable timeframe for a
TSCA section 6(g)(1)(A) exemption for the cleanup of TCE-contaminated
water and groundwater sites. Specifically, EPA requests comment on the
anticipated duration of TCE cleanup projects, and whether there will be
projects that may continue and require the disposal of TCE to
industrial pre-treatment, industrial treatment, or publicly owned
treatment works beyond 50 years.
v. Analysis of the Need for a TSCA Section 6(g)(1)(B) Exemption for
Industrial and Commercial Use of TCE as a Solvent in Closed Loop Vapor
Degreasing Necessary for Human-Rated Rocket Engine Cleaning by NASA and
Its Contractors
    EPA has conducted an analysis of the application of this rulemaking
to the industrial and commercial use of TCE as a solvent in closed-loop
vapor degreasing necessary for human-rated rocket engine cleaning by
NASA and its contractors and proposes to find that a TSCA section 6(g)
exemption is warranted. Under TSCA section 6(g)(1)(B), EPA proposes to
determine that a prohibition at this time on the manufacture,
processing, and distribution in commerce of TCE as a solvent for
closed-loop vapor degreasing for human-rated rocket engine cleaning by
NASA and its contractors would significantly disrupt national security
and critical infrastructure.
    The United States Space Priorities Framework notes that space
systems (e.g., flight components of satellites and space craft) are
part of the nation's critical infrastructure and that the United States
has significant national security interests in space (Ref. 58). NASA
operates on the leading edge of science seeking innovative solutions to
future problems in environments that offer little to no margin for
error. Identification and qualification of compatible materials in the
context of the less forgiving environments in which NASA operates is an
iterative, collaborative process between original equipment
manufacturers and NASA, especially in the case of human space flight
operations (Ref. 59). NASA's mission architecture requirements often
are developed many years in advance of an actual launch occurring. As
part of mission planning, space systems are designed, full scale mock-
ups are built, and mission critical hardware is constructed using
materials qualified for spaceflight. According to NASA, for Artemis
Program applications, in particular, losing access to a qualified high-
performance substance like TCE in a short period of time has the
potential to introduce an unacceptable level of

risk to crew, vehicle, and mission viability (Ref. 43).
    As described by NASA, their use of TCE in closed-loop vapor
degreasing involves cleaning small diameter parts, such as rocket
engine nozzle coolant tubes, and removing the fluids used for
manufacturing. Substitutes for TCE and alternative processes do not
meet the technical specifications required to clean certain complex
aerospace parts, namely small diameter parts. Specifically, these small
diameter parts cannot be cleaned with other solvents due to the
likelihood of entrapment issues (i.e., a solvent carried out of a
degreaser that adheres to or is entrapped in the part being removed)
(Ref. 60). As discussed in Unit V.B.3.a.i., similar concerns have been
expressed by a manufacturer of commercial jetliners and defense, space,
and security systems, although the manufacturer states that potential
alternatives have been identified for nearly all applications. Given
that the small diameter parts identified by NASA are for human-rated
space flight, there is a rigorous safety standard that must be met, and
according to NASA, TCE is the only solvent currently qualified for
degreasing these specific parts. The engines and devices in which these
parts are used include Space Shuttle engines or hardware being reused;
others are designed to leverage proven Space Shuttle technology and
require use of certain fluids, such as TCE, that have been qualified
for human space flight.
    EPA notes that this proposed exemption of use of TCE as a solvent
in closed loop vapor degreasing necessary for human-rated rocket engine
cleaning by NASA and its contractors differs from the exemption for TCE
in vapor degreasing for essential aerospace parts and components,
described in the primary alternative regulatory action. As a principal
matter, this proposed exemption is limited only to NASA and its
contractors due to the critical infrastructure and national security
needs of human-rated spaceflight rocket engines. In contrast, the
alternative is much broader and covers all aerospace entities,
including commercial aviation. This proposed exemption also differs
from the alternative regulatory action in that the exemption is limited
to use of TCE only in closed-loop vapor degreasing, while the
alternative regulatory action would provide an exemption under TSCA
section 6(g) for 7 years before prohibition for all vapor degreasing
with TCE (e.g., open top, in-line conveyorized, in-line web cleaner,
and other types of vapor degreasing in addition to closed loop). Vapor
degreasing as an industry has some of the higher exposures of TCE to
workers and ONUs and this industry would have to make significant
changes in order to comply to the extent possible with a WCPP until
prohibition. However, of the types of vapor degreasing processes,
closed-loop vapor degreasing has the lowest exposures to TCE for
workers and ONUs, and as such, facilities with a closed-loop process
are best situated to comply with an interim WCPP and to the extent
possible, meet the ECEL until prohibition. Further, EPA believes that
the facilities involved in this particular application of vapor
degreasing for human-rated rocket engine cleaning by NASA or their
contractors already have sophisticated industrial hygiene plans in
place. EPA notes that a prohibition on vapor degreasing with TCE for
all uses was proposed in 2017 (Ref. 67). While that proposal was
withdrawn pending the completion of a risk evaluation for TCE under
amended TSCA, which evaluated all conditions of use including vapor
degreasing, EPA expects that since the 2017 proposal, certain
stakeholders have made significant progress in identifying and adopting
substitutes for vapor degreasing with TCE in anticipation of potential
restrictions on TCE under amended TSCA. For instance, EPA is aware that
many users have transitioned to a substitute for TCE in vapor
degreasing where possible or are planning for technologically feasible
adjustments (Refs. 32, 43. 60). EPA requests comment on whether 7 years
is an appropriate timeframe for the proposed TSCA section 6(g)
exemption for industrial and commercial use of TCE in closed loop vapor
degreasing necessary for human-rated rocket engine cleaning by NASA and
its contractors.
vi. Analysis of the Need for TSCA Section 6(g)(1)(A) Exemption for
Certain NASA Uses in an Emergency for Which No Technically or
Economically Feasible Safer Alternative is Available
    EPA considered a TSCA section 6(g) exemption for emergency use of
TCE in the furtherance of NASA's mission. For certain specific
conditions of use, EPA proposes that use of TCE by NASA and its
contractors in an emergency be exempt from the requirements of this
rule because it is a critical or essential use provided that (1) there
is an emergency; and (2) NASA selected TCE because there are no
technically or economically feasible safer alternatives available
during the emergency.
    NASA operates on the leading edge of science seeking innovative
solutions to future problems where even small volumes of an otherwise
prohibited chemical substance could be vital to crew safety and mission
success. During interagency review, NASA expressed concerns that there
will likely be circumstances where a specific, EPA-prohibited condition
of use may be identified by NASA during an emergency as being needed in
order to avoid or reduce situations of harm or immediate danger to
human health, or the environment, or avoid imperiling NASA space
missions. In such cases, it is possible that no technically and
economically feasible safer alternative would be available that meets
the stringent technical performance requirements necessary to remedy
harm or avert danger to human health, the environment, or avoid
imperiling NASA space missions.
    An emergency is a serious and sudden situation requiring immediate
action to remedy harm or avert danger to human health, the environment,
or to avoid imperiling NASA space missions. In NASA's case, there may
be instances where the emergency use of TCE for specific conditions of
use is critical or essential to remedying harm or averting danger to
human health, the environment, or avoiding imperiling NASA space
missions. Because of the immediate and unpredictable nature of
emergencies described in this unit and of the less forgiving
environments NASA operates in that offer little to no margin for error,
it is likely that, at the time of finalization of this proposal,
alternatives to emergency TCE use may not be available in a timely
manner to avoid or reduce harm or immediate danger (Ref. 59). In this
way, these emergencies for particular conditions of use meet the
criteria for an exemption under TSCA section 6(g)(1)(A), because the
emergency use of TCE for listed conditions of use is critical or
essential and no technically and economically feasible safer
alternative will be available in a timely manner, taking into
consideration hazard and exposure.
    In support of the TSCA section 6(g)(1)(A) emergency use exemption,
NASA submitted detailed criteria which they must use to screen,
qualify, and implement materials to be used in spacecraft equipment, as
well as historical case studies that outline the loss of life and loss
of assets in the discharge of previous missions. In one of several
examples detailed, the Apollo I command module fire that claimed the
lives of three American astronauts demonstrated the need for careful
testing and continuity of materials (Ref. 59). Moreover, due to NASA's
rigorous safety testing requirements under various environmental
conditions, technically and economically feasible

safer alternatives may not be readily available during emergencies and
may require certain conditions of use of TCE to alleviate the
emergency.
    In another example, NASA identified a scenario concerning a mission
to the International Space Station (ISS) whereby, during a launch
evolution, the countdown was paused immediately prior to launch (T-2
minutes). NASA engineers identified a clogged filter and supply line as
the primary issue, which required immediate attention (i.e., line
flushing and filter cleaning). In this type of emergency scenario, an
already approved chemical substance rated for space system applications
is necessary to immediately remedy the situation. Although TCE was not
used in this particular incident, if it were needed in the future to
address such an emergency, then the proposed exemption would allow for
its lawful use--the countdown would resume and the launch would occur.
Conversely, without an exemption under the specific condition of use
(e.g., industrial and commercial use in cold cleaning), NASA's use of
TCE would be otherwise prohibited, which would put NASA in an untenable
position of having to choose to either violate the law or place the
mission (and potentially the health and safety of its employees
involved in the mission) at risk.
    The identification and qualification of compatible materials in the
context of aviation is iterative and involves expansive collaboration
between original equipment manufacturers, federal agencies, and
qualifying institutions. This is equally, if not more so, the case in
the context of human space flight operations undertaken by NASA (Ref.
59). NASA's mission architecture requirements often are developed many
years in advance of an actual launch occurring. As part of mission
planning, space systems are designed, full scale mock-ups are built,
and mission critical hardware is constructed using materials qualified
for spaceflight. Once NASA's mission architecture requirements are
developed, NASA may need to retain emergency access to TCE because its
alternatives may not have yet gone through NASA's rigorous
certification process before their use. Allowing NASA to retain
emergency use of TCE would reduce the chances that this rule will
hinder future space missions for which mission architecture
infrastructure is being developed or is already built. While NASA
considers alternatives to the chemical substances it currently uses in
its space system designs, NASA has not yet identified technically and
economically feasible alternatives to proven chemistries in many
current applications. While EPA acknowledges that the use of TCE in
emergency situations may be necessary in the near term, it is also
EPA's understanding that NASA will continue its work to identify and
qualify alternatives to TCE. Thus, EPA is proposing an exemption
duration of 10 years.
b. Proposed TSCA Section 6(g) Exemptions
i. Proposed 10-Year Exemption for Industrial and Commercial Use of TCE
as a Processing Aid for Battery Separator Manufacturing (Lead-Acid and
Lithium Battery Separators)
    For the reasons discussed in this unit, EPA is proposing a 10-year
exemption from the prohibition on the industrial and commercial use of
TCE as a processing aid, specific to battery separator manufacturing.
The proposed conditions for the exemption are: (1) The use of TCE would
be limited to use as a processing aid for battery separator
manufacturing to supply the essential battery components to continue to
support the national economy, national security, and critical
infrastructure; (2) This specific industrial and commercial use of TCE
as a processing aid would be required to be conducted at industrial
facilities already using TCE to manufacture the lithium ion or lead
acid separators; and (3) Owners or operators of facilities where TCE is
used as a processing aid for battery separator manufacturing and
entities that manufacture (including import) TCE as a processing aid
would be required to comply with the WCPP requirements described in
Unit V.A.2. until the expiration of the exemption and the prohibition
compliance date.
ii. Proposed 10-Year Exemption for TCE for Industrial Uses for DoD
Naval Vessel Requirements
    For reasons discussed in this unit, EPA is proposing a 10-year
exemption from the prohibition on industrial and commercial use of TCE
for the industrial and commercial use of TCE as potting compounds for
naval electronic systems and equipment; sealing compounds for high and
ultra high vacuum systems; bonding compounds for materials testing and
maintenance of underwater systems and bonding of nonmetallic materials;
and cleaning requirements (which includes degreasing using wipes,
sprays, solvents, and vapor degreasing) for: materials and components
required for military ordinance testing; temporary resin repairs in
vessel spaces where welding is not authorized; ensuring polyurethane
adhesion for electronic systems and equipment repair and installation
of elastomeric materials; various naval combat systems, radars,
sensors, equipment; fabrication and prototyping processes to remove
coolant and other residue from machine parts; machined part
fabrications for naval systems; installation of topside rubber tile
material aboard vessels; and vapor degreasing required for substrate
surface preparation prior to electroplating processes. The proposed
conditions for the exemption are: (1) The use of TCE would be limited
to use only for DoD naval vessels and their systems, and in the
maintenance, fabrication, and sustainment for and of such vessels and
systems; and (2) Owners or operators of facilities where TCE is used
for DoD naval vessels and entities that manufacture (including import)
or process TCE for use in DoD naval vessels would be required to comply
with the WCPP requirements described in Unit V.A.2. until the
expiration of the exemption and the prohibition compliance date.
iii. Proposed 50-Year Exemption for TCE Laboratory Use for Essential
Laboratory Activities
    For the reasons discussed in this unit, EPA is proposing a 50-year
exemption from the prohibition on industrial and commercial use of TCE,
for other miscellaneous industrial and commercial use of TCE in
laboratory use for essential laboratory activities, excluding the
testing of asphalt, as previously discussed. The proposed conditions
for the exemption are: (1) The use of TCE would be limited to use in an
industrial or commercial laboratory for essential laboratory
activities, including chemical analysis, chemical synthesis, extracting
and purifying other chemicals, dissolving other substances, and
research and development for the advancement of cleanup activities and
analytical methods for monitoring related to TCE contamination or
exposure monitoring, with the exclusion of laboratory testing for
asphalt; (2) Federal agencies and their contractors would be permitted
to conduct research and development activities and test and evaluation
method activities, and similar laboratory activities, provided the use
is essential to the agency's mission; and (3) Owners or operators of
facilities where TCE is used in laboratory settings and entities that
manufacture (including import) or process TCE for use as a laboratory
chemical would be required to comply with the WCPP requirements
described in Unit V.A.2. until the expiration of the

exemption and the prohibition compliance date.
iv. Proposed 50-Year Exemption for Disposal of TCE to Industrial Pre-
Treatment, Industrial Treatment, or Publicly Owned Treatment Works for
the Purposes of Cleanup Projects of TCE-Contaminated Groundwater and
Other Wastewater
    For the reasons discussed in this Unit, EPA is proposing a 50-year
exemption from the prohibition on disposal of TCE to industrial pre-
treatment, industrial treatment, or publicly owned treatment works for
the purposes of cleanup projects of TCE-contaminated groundwater and
other wastewater. The proposed conditions for the exemption are: (1)
The disposal of TCE to industrial pre-treatment, industrial treatment,
or publicly owned treatment works would only be permitted for the
purposes of cleanup projects of TCE-contaminated water and groundwater
at sites undergoing remediation under CERCLA, RCRA, or other Federal,
state, and local government laws, regulations or requirements; and (2)
Owners and operators of the locations where workers are handling TCE
wastewater, and owners and operators of facilities where TCE is
disposed to industrial pre-treatment, industrial treatment, or publicly
owned treatment works, would be required to comply with the WCPP
requirements described in Unit V.A.2. and the recordkeeping
requirements described in Unit V.A.4. until the expiration of the
exemption and the prohibition compliance date.
v. Proposed 7-Year Exemption for Industrial and Commercial Use of TCE
as a Solvent in Closed-Loop Vapor Degreasing Necessary for Human-Rated
Rocket Engine Cleaning by NASA and Its Contractors
    For the reasons discussed in this unit, EPA is proposing a 7-year
exemption from the prohibition on the industrial and commercial use of
TCE as a solvent in closed-loop vapor degreasing necessary for human-
rated rocket engine cleaning by NASA and its contractors, and the
manufacture (including import), processing, and distribution in
commerce of TCE for this use. The proposed conditions for the exemption
are: (1) The use of TCE would be limited to closed-loop vapor
degreasing necessary for human-rated rocket engine cleaning by NASA and
its contractors; and (2) Owners or operators of facilities where TCE is
used in closed-loop vapor degreasing necessary for human-rated rocket
engine cleaning by NASA and its contractors, and entities that
manufacture (including import) or process TCE for such use, would be
required to comply with the WCPP requirements described in Unit V.A.2.
until the expiration of the exemption and the prohibition compliance
date.
vi. Proposed Exemption for Uses of TCE for Emergency Uses in the
Context of Human Space Flight for Certain Uses
    For the reasons discussed in this Unit, EPA is proposing a 10-year
exemption for emergency use of TCE in furtherance of NASA's mission for
the following specific conditions of use:
    (1) Industrial and commercial use as solvent for open-top or
closed-loop batch vapor degreasing;
    (2) Industrial and commercial use as a solvent for cold cleaning;
    (3) Industrial and commercial use as a solvent for aerosol spray
degreaser/cleaner and mold release;
    (4) Industrial and commercial use as a lubricant and grease in tap
and die fluid;
    (5) Industrial and commercial use as a lubricant and grease in
penetrating lubricant;
    (6) Industrial and commercial use as an adhesive and sealant in
solvent-based adhesives and sealants;
    (7) Industrial and commercial as a functional fluid in heat
exchange fluid;
    (8) Industrial and commercial use in corrosion inhibitors and anti-
scaling agents; and
    (9) Industrial and commercial use of TCE as a processing aid.
    EPA is also proposing to include additional requirements as part of
the exemption, pursuant to TSCA section 6(g)(4), including required
notification and controls for exposure, to the extent feasible: (1)
NASA and its contractors must provide notice to the EPA Administrator
of each instance of emergency use within 15 days; and (2) NASA and its
contractors would have to comply with the ECEL.
    EPA is proposing to require that NASA notify EPA within 15 days of
the emergency use. The notification would include a description of the
specific use of TCE in the context of one of the conditions of use for
which this exemption is being proposed, an explanation of why the use
described qualifies as an emergency, and an explanation with regard to
the lack of availability of technically and economically feasible
alternatives.
    EPA expects NASA and its contractors have the ability to implement
a WCPP as described in Unit V.A.2. for the identified uses in the
context of an emergency, to some extent even if not to the full extent
of WCPP implementation. Therefore, EPA is proposing to require that
during emergency use, NASA must comply with the ECEL to the extent
technically feasible in light of the particular emergency.
    Under the proposed exemption, NASA and its contractors would still
be subject to the proposed general recordkeeping requirements discussed
in Unit V.A.
    EPA requests comment on this TSCA section 6(g) exemption for
continued emergency use of TCE in the furtherance of NASA's mission as
described in this Unit, and whether any additional conditions of use
should be included, in particular for any uses qualified for space
flight for which no technically or economically feasible safer
alternative is available. Additionally, EPA requests comment on what
would constitute sufficient justification of an emergency.
4. Other Requirements
a. Recordkeeping
    In addition to the recordkeeping requirements for the WCPP outlined
in this unit, for conditions of use that would not otherwise be
prohibited one year after the effective date of this proposed
regulation, EPA is also proposing that manufacturers, processors,
distributors, and commercial users maintain ordinary business records,
such as invoices and bills-of-lading, that demonstrate compliance with
the prohibitions, restrictions, and other provisions of this proposed
regulation; and to maintain such records for a period of 5 years from
the date the record is generated. EPA is proposing that this compliance
date would begin at the effective date of the rule (60 days following
publication of the final rule in the Federal Register). Recordkeeping
requirements would ensure that owners or operators can demonstrate
compliance with the regulations if necessary. EPA may require more,
less, or different documentation in the final rule based on
consideration of public comments.
b. Downstream Notification
    For conditions of use that are not otherwise prohibited under this
proposed regulation, EPA is proposing that manufacturers (including
importers), processors, and distributors, excluding retailers, of TCE
and TCE-containing products provide downstream notification of the
prohibitions through the Safety Data Sheets (SDS) required by OSHA
under 29 CFR 191.1200(g) by adding to sections 1(c) and 15 of the SDS
the following language:
    After [DATE 6 MONTHS AFTER DATE OF PUBLICATION OF THE

FINAL RULE IN THE FEDERAL REGISTER], this chemical/product is and can
only be domestically manufactured, imported, processed, or distributed
in commerce for the following purposes until the following prohibitions
take effect: (1) Processing as an intermediate (a) for the manufacture
of HFC-134a until [DATE 8.5 YEARS AFTER DATE OF PUBLICATION OF THE
FINAL RULE IN THE FEDERAL REGISTER] and (b) for all other processing as
a reactant/intermediate until [DATE 2 YEARS AFTER DATE OF PUBLICATION
OF THE FINAL RULE IN THE FEDERAL REGISTER]; (2) Industrial and
commercial use as a solvent for open-top batch vapor degreasing until
[DATE 1 YEAR AFTER DATE OF PUBLICATION OF FINAL RULE IN THE FEDERAL
REGISTER]; (3) Industrial and commercial use as a solvent for closed-
loop batch vapor degreasing until [DATE 1 YEAR AFTER DATE OF
PUBLICATION OF THE FINAL RULE IN THE FEDERAL REGISTER], except for
industrial and commercial use as a solvent for closed-loop batch vapor
degreasing necessary for human-rated rocket engine cleaning by NASA and
its contractors until [DATE 7 YEARS AFTER DATE OF PUBLICATION OF THE
FINAL RULE IN THE FEDERAL REGISTER], and except for industrial and
commercial use as a solvent for closed-loop batch vapor degreasing for
rayon fabric scouring for end use in rocket booster nozzle production
by Federal agencies and their contractors until [DATE 10 YEARS AFTER
DATE OF PUBLICATION OF THE FINAL RULE IN THE FEDERAL REGISTER]; (4)
Industrial and commercial use in processing aid a) for battery
separator manufacturing until [DATE 10 YEARS AFTER DATE OF PUBLICATION
OF THE FINAL RULE IN THE FEDERAL REGISTER] and b) in process solvent
used in polymer fiber spinning, fluoroelastomer manufacture and
Alcantara manufacture; in extraction solvent used in caprolactam
manufacture; and in precipitant used in beta-cyclodextrin manufacture
until [DATE 2 YEARS AFTER DATE OF PUBLICATION OF THE FINAL RULE IN THE
FEDERAL REGISTER]; (5) Industrial and commercial uses for DoD naval
vessels and their systems, and in the maintenance, fabrication, and
sustainment for and of such vessels and systems until [DATE 10 YEARS
AFTER DATE OF PUBLICATION OF THE FINAL RULE IN THE FEDERAL REGISTER];
and (6) Industrial and commercial use for laboratory use for essential
laboratory activities until [DATE 50 YEARS AFTER DATE OF PUBLICATION OF
THE FINAL RULE IN THE FEDERAL REGISTER].
    The intention of downstream notification is to spread awareness
throughout the supply chain of the restrictions on use of TCE under
TSCA as well as provide information to commercial end users about
allowable uses of TCE until the prohibition compliance dates.
    To provide adequate time to update the SDS and ensure that all
products in the supply chain include the revised SDS, EPA is proposing
a two-month period for manufacturers and a six-month period for
processors and distributers to implement the proposed SDS changes
following publication of the final rule.
    EPA requests comments on the appropriateness of identified
compliance timeframes for recordkeeping and downstream notification
requirements described in this unit.

B. Primary Alternative Regulatory Action

    As indicated by TSCA section 6(c)(2)(A)(iv)(II) through (III), EPA
must consider and publish a statement based on reasonably available
information with respect to the reasonably ascertainable economic
consequences of the rule, including consideration of the costs and
benefits and the cost effectiveness of the proposed regulatory action
and one or more primary alternative regulatory actions considered by
the Agency. This unit includes a description of the primary alternative
regulatory action considered by the Agency. An overview of the proposed
regulatory action and primary alternative regulatory actions for each
condition of use is in Unit V.C.
    The primary alternative regulatory action described in this notice
of proposed rulemaking (NPRM) and considered by EPA combines
prohibitions and requirements for a WCPP. While in some ways it is
similar to the proposed regulatory action, the primary alternative
regulatory action described in this NPRM differs from the proposed
regulatory action by providing longer timeframes for prohibitions, and
by describing an ECEL based on a different health endpoint (i.e.,
immunotoxicity), as part of the WCPP that would be required for the
conditions of use of TCE that would be permitted to continue for longer
than one year after publication of the final rule until the prohibition
compliance dates. As described in Unit IV.B., this ECEL is based on the
endpoint used for EPA's unreasonable risk determination for TCE under
TSCA, (i.e., immunotoxicity (Ref. 2), rather than the most sensitive
health endpoint (developmental toxicity), which is the basis for the
ECEL for the WCPP under the proposed regulatory action (the rationale
for these differences is described in Unit VI.A.1.a.). EPA requests
comment on this primary alternative regulatory action and whether any
elements of this primary alternative regulatory action described in
this unit should be considered as EPA develops the final regulatory
action. For example, EPA could finalize a rule that includes the longer
timeframes for prohibitions that are included in this primary
alternative regulatory action and the ECEL based on the fetal cardiac
defects endpoint (0.0011 ppm) that is included in the proposed
regulatory action. EPA also requests comment on the practicability of
the timeframes outlined in this unit compared to the timeframes
identified for the proposed regulatory action in Unit V.A.
1. Prohibitions
    The primary alternative regulatory action considered by EPA would
prohibit the manufacture (including import) and processing of TCE for
all uses; prohibit the distribution in commerce and industrial and
commercial use of TCE, as well as prohibitions on the disposal of TCE
to industrial pre-treatment, industrial treatment, or publicly owned
treatment works. The primary alternative regulatory action includes
longer compliance timeframes for all prohibitions.
    Under the primary alternative action, the prohibitions would follow
a staggered schedule and would generally take effect three months later
than in the proposed regulatory action. Under a compliance timeframe
that would be three months longer than the proposed regulatory action,
the prohibitions for the manufacturing (including import) and
processing would come into effect in 180 days (6 months) for
manufacturers and 270 days (9 months) for processors, except for the
manufacturing and processing associated with certain processing and
industrial and commercial uses described later in this unit, due to
supply chain considerations. Associated with this prohibition, EPA
would prohibit the manufacturing (including import) and processing for
all uses, including for all consumer uses, under the primary
alternative regulatory action.

    The prohibition compliance dates for most industrial and commercial
users would be one year after the publication of the final rule under
the primary alternative regulatory action. However, under the primary
alternative regulatory action, there would be longer timeframes for the
prohibition of some industrial and commercial uses and for the
associated manufacturing (including import) and processing. For all
manufacturing (including import), processing, and industrial and
commercial use of TCE that would continue more than one year after the
publication of the final rule, the WCPP would be in effect until the
respective prohibition compliance dates or, if applicable, expiration
of the TSCA section 6(g) exemption. The WCPP under the primary
alternative would include an ECEL of 0.004 ppm, as described in Units
IV.B. and V.B.2. Furthermore, to aid with the implementation of the
prohibitions under the primary alternative regulatory action, the
prohibitions on distribution in commerce of TCE would take effect
concurrent with the compliance date for the prohibition on the
manufacture and processing TCE for a particular condition of use.
    For the two conditions of use that encompass industrial and
commercial batch vapor degreasing (i.e., open-top and closed-loop),
prohibitions under the primary alternative regulatory action described
in this unit would take effect in 24 months for manufacturers, in 27
months for processors, and in 30 months for the industrial and
commercial users of TCE used as a solvent for open-top and closed-loop
batch vapor degreasing after the publication date of the final rule
(with the exception of industrial and commercial use of TCE as a
solvent for closed-loop batch vapor degreasing for rayon fabric
scouring for end use in rocket booster nozzle production by Federal
agencies and their contractors, which is described in Unit V.B.3.).
    For certain processing and industrial and commercial conditions of
use, the prohibitions under the primary alternative regulatory action
described in this unit would take effect in two and a half years after
the publication date of the final rule for manufacturers and in three
years after the publication date of the final rule for processors for
two conditions of use: (1) Processing as a reactant/intermediate, and
(2) Industrial and commercial use as a processing aid in: process
solvent used in battery manufacture; process solvent used in polymer
fiber spinning, fluoroelastomer manufacture and Alcantara manufacture;
extraction solvent used in caprolactam manufacture; and precipitant
used in beta-cyclodextrin manufacture. Additionally, a TSCA section
6(g) exemption would be part of the primary alternative regulatory
action for the industrial and commercial use of TCE as a processing aid
(specifically for battery separator manufacture) and industrial and
commercial use of TCE as a solvent for closed-loop batch vapor
degreasing for rayon fabric scouring for end use in rocket booster
nozzle production by Federal agencies and their contractors (see Unit
V.B.3.).
    Furthermore, compliance dates for prohibition would vary for
processing TCE as an intermediate (specifically for HFC-134a
manufacture), which would be subject to a longer phaseout, and for the
prohibition of processing TCE as a reactant/intermediate. Under the
primary alternative regulatory action, the manufacturing (including
import) and processing of TCE as an intermediate for the manufacture of
HFC-134a would be prohibited. Under the primary alternative regulatory
action, there would be a nine-and-a-half-year phaseout (with an extra
year to start compliance compared to the eight-and-a-half-year phaseout
for the proposed regulatory action) following the requirements
discussed in this unit. Under the primary alternative regulatory
action, the prohibition would start one year later than under the
proposed regulatory action, and thus the compliance timeframe would be
one year longer than under the proposed regulatory action described in
Unit V.A.1.b. Under the primary alternative regulatory action, a
phaseout on processing of TCE as an intermediate for the manufacture of
HFC-134a would begin at the final rule's effective date and end nine
years and six months after the publication of the final rule. Within 18
months after the publication of the final rule, any facility using TCE
as a feedstock to manufacture HFC-134a in the United States would
establish a baseline within 12 months after the publication of the
final rule of the annual quantity of TCE processed by the facility as a
feedstock to manufacture HFC-134a. While this is similar to the
proposed regulatory action, the timeframes allowed for establishment of
the baseline would be longer under the primary alternative regulatory
action. The manufacturer would use the average of any 12 consecutive
months in the preceding 36 months to calculate the baseline and would
have records that demonstrate how the baseline annual volume was
calculated. Following the establishment of a baseline volume, under the
alternative regulatory action, following a similar four-step phaseout
process described in Unit V.A., the following compliance dates would
take effect after the publication of the final rule: (1) In three years
and six months each manufacturer of HFC-134a who uses TCE as an
intermediate would not be permitted to process TCE as an intermediate
at an annual volume greater than 75 percent of the baseline so
established; (2) In five years and six months each manufacturer of HFC-
134a who uses TCE as an intermediate would not be permitted to process
TCE as an intermediate at an annual volume greater than 50 percent of
the baseline so established; (3) In seven years and six months each
manufacturer of HFC-134a who uses TCE as an intermediate would not be
permitted to process TCE as an intermediate at an annual volume greater
than 25 percent of the baseline so established; and (4) In nine years
and six months each manufacturer of HFC-134a would be prohibited from
using TCE as an intermediate. Additionally, manufacturing (including
import) for this condition of use and distribution in commerce for this
condition of use would follow a corresponding longer phaseout timeframe
to account for the availability of TCE through the supply chain during
the period of the phaseout of processing TCE as an intermediate for the
manufacture of HFC-134a. Under the primary alternative regulatory
action, regulated entities would keep records of the annual quantity of
TCE purchased and processed from the year 2024 until the termination of
all processing of TCE as an intermediate.
    EPA requests comment on the practicability of the timeframes
outlined in this unit compared to the timeframes identified for the
proposed regulatory action in Unit V.A.1.c., including consideration of
the need for manufacturing (including import), and distribution in
commerce to continue during the period of the phaseout.
    Furthermore, with regard to the prohibition of the disposal of TCE
to industrial pre-treatment, industrial treatment, or publicly owned
treatment works, under the primary alternative regulatory action, the
prohibition would start three months later than under the proposed
regulatory action, and thus the compliance timeframe would be two years
and three months longer than under the proposed regulatory action
described in Unit V.A.4. (description of disposal for the purposes of
this rulemaking is provided in Unit III.B.2.d.). Under the primary
alternative regulatory action, the prohibition described in this unit
would take effect in three years for domestic manufacturers,
processors, and

industrial and commercial users disposing of TCE to wastewater,
including disposing of TCE-containing wastewater to industrial pre-
treatment, industrial treatment, or publicly owned treatment works. EPA
recognizes there may be challenges in identifying and implementing an
alternative disposal process separate from disposal of TCE to
industrial pre-treatment, industrial treatment, or publicly owned
treatment works. EPA requests comment on whether the three-year
alternative timeline would be practicable or whether additional time is
needed, for example, for a regulated entity to implement a change to
their wastewater collection, treatment, or disposal processes or
infrastructure, and what those alternative disposal methods may be.
2. Workplace Chemical Protection Program for Certain Conditions of Use
    As in the proposed regulatory action described in Unit V.A.1.,
EPA's primary alternative regulatory action would include a WCPP as a
requirement, which would encompass an ECEL as well as dermal
requirements to reduce inhalation and dermal exposures to TCE. However,
the WCPP under the primary alternative regulatory action would include
an ECEL based on a different health endpoint, immunotoxicity, as
further discussed in this unit. The WCPP would be in place until the
prohibition compliance date for those conditions of use of TCE that
would continue for longer than one year after publication of the final
rule, which would be: manufacturing (including import); processing: as
a reactant/intermediate; incorporation into formulation, mixture or
reaction product; repackaging; recycling; industrial and commercial
use: as a solvent for open-top batch vapor degreasing; industrial and
commercial use as a solvent for closed-loop batch vapor degreasing; and
industrial and commercial use as a processing aid in process solvent
used in battery manufacture; process solvent used in polymer fiber
spinning, fluoroelastomer manufacture and Alcantara manufacture;
extraction solvent used in caprolactam manufacture; and precipitant
used in beta-cyclodextrin manufacture.
    As discussed in Unit V.A.2., and for the reasons described in Unit
V., EPA does not believe that long-term implementation of the WCPP
would be a feasible means of addressing unreasonable risk indefinitely
and that prohibition of the affected COUs would ultimately be necessary
to eliminate the unreasonable risk. Under the primary alternative
regulatory action, the WCPP for several conditions of use of TCE would
reduce to the extent possible the unreasonable risk during the time
period before a prohibition would become effective.
    For the primary alternative regulatory action, the WCPP would
encompass an ECEL based on immunotoxicity, following the associated
implementation requirements discussed in Unit V.A.2., in addition to
longer timeframes described in this unit. EPA's primary alternative
regulatory action includes an ECEL of 0.0040 ppm (0.021 mg/m3) as an
eight-hour TWA, which is based on the chronic non-cancer occupational
HEC for autoimmunity (Ref. 14). As discussed in Unit VI.A., among the
adverse health effects, the drivers for EPA's revised unreasonable risk
determination for TCE under TSCA were identified as cancer,
immunotoxicity, acute immunosuppression and chronic autoimmunity from
inhalation and dermal exposures (Ref. 2). Therefore, reducing the
remaining exposures to or below the ECEL of 0.0040 ppm would address
the unreasonable risk of injury to health from TCE that is driven by
inhalation exposures in an occupational setting (Refs. 1, 14). If
ambient exposures are kept at or below the eight-hour ECEL of 0.0040
ppm, EPA expects that workers and ONUs would be protected against not
only the chronic non-cancer effects for autoimmunity described in Unit
III.B.2., but also effects resulting from acute non-cancer exposure
(immunosuppression) and cancer. Associated with the ECEL of 0.0040 ppm,
under the alternative regulatory action, EPA would establish an ECEL
action level at half of the eight-hour ECEL, or 0.002 ppm as an eight-
hour time-weighted average.
    EPA believes that longer timeframes may facilitate compliance;
therefore, the primary alternative regulatory action would provide
longer timeframes for implementation of a WCPP than the proposed
regulatory action. With a compliance timeframe that would be six months
later than in the proposed regulatory action, the compliance timeframe
for the WCPP under the primary alternative regulatory action would be
extended as follows: regulated entities would establish initial
exposure monitoring according to the process outlined in Unit V.A.2.ii.
within 12 months (in contrast to six months in the proposed regulatory
action described in Unit V.A.2.ii.) and proceed accordingly, based on
the outcome of the initial monitoring. EPA requests comment on the
ability of regulated entities to conduct initial monitoring within 12
months, anticipated timeframes for any procedural adjustments needed to
comply with the requirements, and the extent to which this option could
result in additional exposure, compared to the proposed regulatory
option as described in Unit V.A. Overall, EPA requests comment on the
practicability of the timeframes outlined in this unit, when compared
to the timeframes identified for the proposed regulatory action in Unit
V.A. EPA requests comment on whether any elements of the primary
alternative regulatory action described in this unit should be
considered as EPA develops the final regulatory action, e.g., whether
EPA should consider the timeframes for implementation of a WCPP
presented in this primary alternative regulatory action and the ECEL
value presented in the proposed regulatory action.
    EPA does not have sufficient information as to whether the
conditions of use that would continue for longer than one year under
the primary alternative regulatory action listed in this unit could
meet requirements of a WCPP for TCE, including an ECEL of 0.0040 ppm
for TCE. Therefore, EPA requests comment on the existing practices
(e.g., engineering controls, administrative controls, PPE) involving
TCE use in these conditions of use, as to whether activities may take
place in closed systems and the degree to which users of TCE in these
sectors could successfully implement an ECEL of 0.0040 ppm, dermal
protection, and ancillary requirements, described in Unit V.A.2., until
the prohibitions would become effective, including for the
manufacturing, processing, and distribution in commerce that account
for the supply chain.
3. TSCA Section 6(g) Exemptions
    Under TSCA section 6(g)(1), EPA may grant an exemption from a
requirement of a TSCA section 6(a) rule for uses that are critical or
essential. Based on discussions with and information provided by
industry stakeholders and consultation with other Federal agencies, EPA
has analyzed the need for two different exemptions, described in the
proposed regulatory action discussed in Units I.A.3.a. and b., and
would grant both with a longer time limit if the primary alternative
regulatory action described in this NPRM is adopted in the final rule.
Furthermore, under the primary alternative regulatory action, EPA has
analyzed the need for additional exemptions for essential uses of open-
top and closed-loop batch vapor degreasing for aerospace use (including

for rayon fabric scouring for rocket booster nozzle production) as well
as narrow tubing used in medical devices, and EPA would provide the
additional exemptions if the primary alternative regulatory action
described in this NPRM is adopted in the final rule. (EPA notes that
the use of TCE for vapor degreasing narrow tubing used in medical
devices is not excluded by TSCA section (3)(2)(B)(vi) because TCE is
not intended to become part of the medical device that incorporates the
narrow tubing). This unit presents the results of the analysis for the
requested exemption for industrial and commercial use of TCE in vapor
degreasing, as well as the time limits indicated under the primary
alternative regulatory action.
a. Primary Alternative Analysis of the Need for TSCA Section 6(g)(1)
Exemptions for Uses of TCE That Are Critical or Essential
i. Analysis of the Need for a TSCA Section 6(g)(1)(B) Exemption for
Industrial and Commercial Use of TCE in Vapor Degreasing for Essential
Aerospace Parts and Components
    EPA has conducted an analysis of the application of this rulemaking
to the industrial and commercial use of TCE in vapor degreasing and
found that a TSCA section 6(g) exemption may be warranted for certain
aerospace parts and components if the primary alternative regulatory
action considered by EPA is adopted, in its entirety or in relevant
part, in the final rule.
    EPA received a request for a TSCA section 6(g) exemption from
prohibition for the use of TCE in vapor degreasing of aerospace parts
from a manufacturer of commercial jetliners and defense, space, and
security systems (Refs. 60 and 61). As the requester describes, they
manufacture and procure these parts and have identified that TCE vapor
degreasing is necessary due to technical challenges with other
substitute chemicals or alternative methods.
    The requester has spent many years developing, qualifying, and
implementing alternative materials and processes to replace TCE vapor
degreasing with aqueous cleaning where technically viable. According to
the requester, while the transition to aqueous cleaning has been
successful for many detail parts (e.g., stringers, spars, seat tracks,
brackets, etc.), substitutes and alternative processes do not meet the
technical specifications required to clean certain complex aerospace
parts, specifically, gaseous oxygen tubing systems, non-oxygen tubing,
as well as honeycomb core and rotorcraft mechanical systems. The
requester notes the ongoing research and development activities over
the years for the TCE vapor degreasing uses without viable
alternatives, and highlights that a potential replacement technology
has been identified for vapor degreasing oxygen and non-oxygen tubing
systems. However, for the honeycomb core and rotorcraft mechanical
systems parts, the requestor explains the continued challenge to
identify a replacement solvent due to entrapment issues (i.e., a
solvent carried out of a degreaser that adheres to or is entrapped in
the part being removed) and processing concerns.
    The requester notes that an adequate transition period for this
technically challenging aerospace use requires substantial investment
and time to develop viable alternatives. The requester is currently in
the process of identifying a replacement solvent that can adequately
clean, cause no harm to parts, and is not an equally toxic material to
TCE. Based on the submitted request, conversion from vapor degreasing
to aqueous cleaning is a capital-intensive investment that the
requester expects would require several years to plan, permit,
construct, and install. Additionally, the requester notes that the
aerospace industry needs to ensure that aerospace parts meet DOD and
other Federal Aviation Administration (FAA) specifications to ensure
safety of flight. For example, in order to replace the chemical with an
alternative, the requester notes that they must identify, test, and
select an alternative that meets technical requirements derived from
FAA mandated standards for a typical part used in a commercial
aircraft, such as specifications for specific gravity (ASTM D 792),
Water Absorption (ASTM D 750), and other test requirements, which may
be a lengthy process (Ref. 62). According to the information submitted,
certification with FAA could take at least nine months for individual
parts of components or up to several years for major subsystems or
complete aircraft (Ref. 62). The requester also notes that while they
do not know the extent that their supply chain has transitioned away
from use of TCE in vapor degreasing, TCE has been used in vapor
degreasing to meet required levels of cleanliness of certain supplied
parts by long-standing design specifications that are incorporated into
contracts of a complex supply chain. The requester also told EPA the
suppliers are not required to inform the requester of the process they
use to clean parts that the supplier provides to the requester, and the
requester therefore may not know which solvent a supplier has selected
for vapor degreasing or what factors were considered when selecting
cleaning systems. According to the requester, material declarations and
auditing processes to validate usage may be burdensome, considering
that a large portion of the requester's supply chain includes small
suppliers. Due to the concerns raised with transitioning to aqueous
cleaning or another new cleaning method, the requester has requested
that EPA exempt use of TCE in vapor degreasing of aerospace parts for
10 years.
    As discussed in this unit, substitute chemicals for vapor
degreasing of aerospace parts may not be available at this time for
meeting the cleanliness standards of certain parts as required by DOD
and FAA specifications or other specifications included in existing
contracts within the supply chain such that significant disruption to
national security and critical infrastructure would occur without a
longer timeframe for transition to an alternative. More time is needed
for companies to make the capital-intensive transition from TCE vapor
degreasing to aqueous cleaning for those parts that can be cleaned
using the aqueous method. In addition, the requester states that they
are continuing to work towards identifying a replacement solvent that
is able to adequately clean complex machining parts and actuation
systems parts without harming them and that is not a regrettable
substitution. Therefore, EPA has preliminarily determined that if the
use of TCE for vapor degreasing were not available in the near term for
aerospace parts, or if industry could not meet the requirements of the
prohibition considered as the proposed regulatory action, compliance
with such requirement could significantly disrupt national security and
critical infrastructure. In addition, due to availability concerns, EPA
has preliminarily determined that a ban on the manufacture, processing,
and distribution in commerce of TCE for vapor degreasing of aerospace
parts could also significantly disrupt national security and critical
infrastructure. A prohibition on the use of TCE for vapor degreasing of
aerospace parts could negatively affect DOD's capability and readiness,
which includes the ability to adequately maintain aircraft. Such a
prohibition could also negatively affect the maintenance of civilian
aircraft and potentially have impacts on the safety of civilian flight.
    Similarly, EPA is aware of a highly specific use of vapor
degreasing for

aerospace components as part of production of booster rocket nozzles
for national security or critical infrastructure uses (Ref. 43). In the
production of booster rocket nozzles, TCE is used in vapor degreasing
as a solvent in rayon fabric scouring, an intensive cleaning process to
remove contaminants. Cleaning is a critical step of this process; if
contaminants are not sufficiently removed in the scouring stage, the
fabric will be degraded during the chemical reaction that occurs during
carbonization which could result in failure of the nozzle during a
launch and catastrophic effects for the rockets.
    A Federal agency involved in this use, specifically NASA, has
attempted at length to identify an alternative to TCE in vapor
degreasing; while NASA had preliminarily identified an alternative
solvent, the manufacturer of the substitute chemical announced they
would be voluntarily ceasing production (Ref. 63), making this
alternative solvent no longer viable. NASA has restarted the
identification and qualification of a non-TCE cleaning method. While
aqueous cleaning has been explored as an alternative method of rayon
fabric scouring, it is not a viable alternative as the rayon fiber is
hydrophilic and water can cause damage to the fiber itself, impacting
its ablation performance (Ref. 43). Currently, substitutes and
alternative processes do not meet the technical specifications required
to clean the rayon fabric in order to safely produce and launch rockets
that are important for national security or critical infrastructure.
NASA has provided to EPA an estimated timeline for the identification
and replacement of TCE in the vapor degreasing of this component. The
replacement of TCE involves intense testing as it is part of
spaceflight, notably a new process would have to undergo various rounds
of testing culminating in a full-scale static motor test using a
booster nozzle manufactured with an alternative cleaning solvent. For
NASA specifically, the first opportunity to conduct a full-scale static
motor test with a booster nozzle produced using a non-TCE alternative
would be 2027; before that is planned to occur, NASA has launches
planned with eight booster rockets, which cannot proceed unless all
components are safely produced. Therefore, EPA has preliminarily
determined that if TCE was not available for this sub-use of closed-
loop batch vapor degreasing for this aerospace component, there would
be a significant, disruptive impact on national security and critical
infrastructure. In addition, due to availability concerns, EPA has
preliminarily determined that a ban on the manufacture, processing, and
distribution in commerce of TCE for vapor degreasing of aerospace parts
could also significantly disrupt national security and critical
infrastructure.
ii. Analysis of the Need for a TSCA Section 6(g)(1)(A) Exemption for
Industrial and Commercial Use of TCE in Closed-Loop and Open-Top Batch
Vapor Degreasing for Narrow Tubing Used in Medical Devices
    EPA also finds that a TSCA section 6(g)(1)(A) exemption may be
warranted for vapor degreasing of narrow metal tubing used in medical
devices if the primary alternative regulatory action considered by EPA
is adopted in the final rule. According to a manufacturer of metal
tubing for medical devices (Ref. 64), TCE is the only solvent that they
have found that effectively removes all lubricants from their tubing
products, allowing them to meet the stringent cleanliness standards for
medical devices.
    Information provided to EPA from the tubing manufacturer indicates
that their tubing products consist of over 20 different alloys
processed with more than 25 different lubricants, for use primarily in
the medical industry. The tubing is incorporated into devices used in
the body for diagnostic and surgical procedures as well as permanent
implants for orthopedic and cardiovascular applications. The tubing
produced by the manufacturer ranges in diameter from 0.005'' to
0.625'', and both the inner and outer diameters of the tubing must be
degreased at various points in the manufacturing process (Ref. 64).
    According to this manufacturer, the use of specialty lubricants in
the drawing and annealing processes create unique degreasing demands
for narrow tube manufacturers and TCE has historically been the
industry standard for effective removal of these lubricants.
Cleanliness is paramount, as even the slightest degreasing failure may
cause corrosion, which could result in a critical failure of an
implantable medical device. Alternative solvents such as methylene
chloride or 1-bromopropane are not feasible alternatives for a variety
of reasons, including that they do not always achieve the required
cleanliness standards, could result in a facility exceeding emission
caps under the Clean Air Act, and are also in the process of being
regulated by EPA under TSCA. Other alternative chemicals have been
explored by the manufacturer, such as parachlorobenzotrifluoride, which
is not a hazardous air pollutant under the Clean Air Act. While
promising, this solvent could not remove some of the manufacturer's
lubricants and specialty coatings, thus not meeting the customer's
cleanliness standard. This alternative is also flammable, which would
require additional equipment design and infrastructure to use safely.
    The information provided by this manufacturer of tubing for use in
medical devices regarding TCE vapor degreasing is consistent with the
information provided by the aerospace industry regarding challenges
with finding a replacement for TCE in vapor degreasing of tubing. It is
also consistent with information provided to EPA during the public
comment period for EPA's 2017 proposal on TCE in vapor degreasing (82
FR 7432, January 19, 2017). A commenter on that proposal indicated that
aqueous cleaners did not effectively remove most of the materials in
their lubrication system, so effective lubricants and coating systems
would need to be developed that are compatible with aqueous cleaners
(Ref. 65). Experiments with other lubricants were not successful, the
commenter found that lubricants that could be effectively aqueous
degreased were less effective at lubricating, requiring more drawing
steps as well as more cleaning steps. Further, according to this
commenter, aqueous cleaning requires large, heated water tanks and hot
air drying chambers, increasing energy use and industrial effluent
volumes.
    In addition, EPA did not impose additional Clean Air Act emission
reductions on aerospace manufacturing and maintenance facilities or on
facilities manufacturing narrow tubing in 2007, recognizing the unique
nature of the vapor degreasing done by these industries. In the 2007
final rule, EPA found that the level of control called for by the 1994
National Emission Standard for Halogenated Solvent Cleaning for
aerospace manufacturing and maintenance and narrow tube manufacturing
facilities reduced hazardous air pollutant emissions to levels that
presented an acceptable level of risk, protected public health with an
ample margin of safety, and prevented any adverse environmental effects
(Ref. 66). As noted in the 2007 final rule, the finding regarding an
``ample margin of safety'' was based on a consideration of the
additional costs of further control as represented by compliance with
emissions limits adapted for these industry sectors, considering
availability of technology, costs and time to comply with further
controls.

EPA further notes that the term ``narrow tube'' as used in the 2007
final rule was tubing with a portion of the outside diameter being a
quarter of an inch or less, which is different from the diameters
provided by the narrow tube manufacturer (Ref. 64).
    EPA acknowledges the importance of properly cleaned narrow tubing
used in medical devices. The failure of a medical device used in a
medical or surgical procedure, or implanted in the body, can have
immediate and significant negative impacts on human health. Further, a
complete prohibition on the use of TCE for vapor degreasing in the near
term could result in shortages of narrow tubing for use in such medical
devices, which would also have significant negative impacts on human
health. Therefore, EPA requests comment on the extent to which the use
of TCE for vapor degreasing of narrow tubing is a critical use for
which no technically and economically feasible safer alternative is
available. In addition, due to availability concerns, a ban on the
manufacture, processing, and distribution in commerce of TCE for vapor
degreasing of narrow tubing used in medical devices could significantly
disrupt a critical use for which no technically and economically
feasible safer alternative is available.
iii. Analysis of the Need for a TSCA Section 6(g)(1)(A) Exemption for
Industrial and Commercial Use of TCE as a Processing Aid for Specialty
Polymeric Microporous Sheet Materials
    EPA has conducted an analysis of the application of this rulemaking
to the industrial and commercial use of TCE as a processing aid and
preliminarily found that a TSCA section 6(g)(1)(A) exemption may be
warranted for certain industrial and commercial purposes if the primary
alternative regulatory action considered by EPA is adopted, in its
entirety or in relevant part, in the final rule. As part of industry
stakeholder engagement, EPA was made aware that at least one U.S.
materials manufacturer relies on TCE to manufacture a specialty
microporous sheet material. This company has requested an exemption
under TSCA section 6(g) for the continued use of TCE for this purpose
(Ref. 67).
    As the requestor describes, specialty polymeric microporous sheet
materials are fundamental components in the production of critical or
essential products. EPA preliminarily agrees that certain applications
of these specialty polymeric microporous sheet materials are critical
and essential uses for which no technically and economically feasible
safer alternative is available. This exemption on processing TCE would
be limited to processing for applications of the specialty polymeric
microporous sheet materials that are critical and essential,
specifically; driver's licenses and identification cards of U.S. states
and territories; passports (including U.S. passports and e-passports);
labels for chemical drums, complex filtration elements and cartridges
(such as for oil/water and bilge water separations); and for use in
membranes in energy recovery ventilators. Any application of the
specialty polymeric microporous sheet materials for uses not listed
above would not be covered under this exemption.
    EPA believes that these uses would preliminarily also qualify for
an exemption under TSCA section 6(g)(1)(B). These critical and
essential products are also important for the national economy,
national security, and critical infrastructure and EPA preliminarily
agrees that compliance with the prohibition within the timeframes
proposed would be disruptive. The proper identification of individuals
is important for maintaining national security and critical
infrastructure. Systems such as travel, healthcare, and law are all
reliant on identification. Further, the proper labeling of chemicals is
important for protecting critical infrastructure. Similarly, complex
filtration elements and cartridges (such as for oil/water and bilge
water separations) and membranes in energy recovery ventilation are
essential for the operations of critical infrastructure.
    Each of these products includes the use of TCE in their
development. The requester described the specific use of TCE as a
``process solvent'' during the manufacturing of a ``unique polymeric
microporous sheet material'' (Ref. 67). The company makes the
microporous sheet material using process oil (white mineral oil) during
the extrusion process in order to form a thin plastic sheet containing
55-60% process oil by weight. The process oil is then removed from the
plastic sheet, which requires the use of a solvent (i.e., TCE) to
rapidly extract the process oil and leave behind the desired
microporosity for the material. The requestor describes how specific
microporosity is important for performance of the material. Once the
solvent has removed the oil from the sheet, the solvent must be
evaporated to remove it from the sheet; post-evaporation, the separator
must leave behind the desired microporosity crucial to the performance
of the material. Finally, the extracted oil and much of the TCE is
captured and reused in the extraction process. TCE that is not captured
and reused is released from a discharge stack; the requestor describes
that the air released contains no more than 10 ppm of TCE.
    The requestor describes this manufacturing process as well-
established and reliant on TCE as a high-performance process solvent
that provides a unique combination of chemical properties (e.g., non-
flammability, rapid extrusion of process oil, compatibility with
process equipment, etc.). The requestor describes how this unique
combination of properties facilitate the controlled removal of process
oil in the production of the specialty polymeric microporous sheet
material, resulting in the specific microporosity important for the
performance of the material.
    The requester has provided some details to EPA on its efforts to
reduce worker exposure to TCE. The exposure mitigation program includes
a separate area under negative pressure for TCE processing and use of
PPE as necessary to comply with the OSHA PEL for TCE (Refs. 67, 10).
While EPA's proposed ECEL is much lower than the OSHA PEL, EPA expects
the requester to make appropriate changes to its worker exposure
mitigation program to comply with the WCPP and attempt to meet the ECEL
to the extent possible for the duration of this exemption.
    According to the requester, there are several properties that make
TCE uniquely suitable for use in the manufacture of the specialty
microporous sheet material. The key properties described by the
requester include TCE's rapid extraction of process oil, the ease by
which TCE is distilled from the process oil for recovery and reuse, and
its vapor pressure, which both allows for evaporation and permits
condensation from the atmosphere. TCE is also non-flammable. The
requester evaluated more than a dozen potential alternatives that could
be compatible with their process for manufacturing specialty polymeric
microporous sheet materials, including hexane, trans-1,2-
dichloroethylene, perchloroethylene, and 1-bromopropane. Many of these
substitutes were found to be less effective than TCE at extracting
process oils, while some were not as easily recovered and reused. Even
the more promising solvents, such as perchloroethylene, were not drop-
in replacements and would, according to the requester, require
expensive equipment modifications and a multi-year approval process.
Many of the potential substitute chemicals would need to be blended
with an HFC that is

being phased out, or the chemical itself is being phased out due to
concern over PFAS or due to high Global Warming Potential. In addition
to these challenges, the requestor describes how any blend would be a
challenging substitute because the different chemicals in the blend
evaporate at different rates and could become flammable during this
process. The requester emphasized that it is using modeling to seek out
potential alternatives, but that further study is required and that
there is no other chemical alternative that is suitable or available to
replace TCE in this process. Based on the requester's submission and
EPA's general understanding of the manufacturing process for the
specialty microporous sheet material, EPA believes that there are no
feasible alternatives to TCE available at present.
    While the requester did not describe a time limit for the
exemption, EPA has identified a 15-year time-limited TSCA section 6(g)
exemption under the alternative regulatory action. EPA believes that a
15-year exemption from the prohibition on the industrial and commercial
use of TCE as a processing aid, specific to the manufacturing of
specialty microporous sheet materials, would be reasonable because it
would be sufficient to provide EPA with an updated analysis of any
technically feasible alternative, the supply chain of the U.S.
materials industry, as well as global innovation and production in
high-technology products. Under TSCA section 6(g), EPA can consider
revisiting or extending time-limited exemptions by rulemaking until a
safer, feasible alternative becomes available. EPA requests comment on
whether 15 years is an appropriate timeframe for the proposed TSCA
section 6(g) exemption for industrial and commercial use of TCE as a
processing aid for specialty polymeric microporous sheet materials.
b. Primary Alternative Exemptions for Uses of TCE That Are Critical or
Essential
i. Primary Alternative 15-Year Exemption for Industrial and Commercial
Use as a Processing Aid for Battery Separator Manufacturing (Lead-Acid
and Lithium Battery Separators)
    As part of the primary alternative regulatory action, based on the
analysis in Unit V.A.3.a.i., EPA would grant a 15-year exemption from
the prohibition on TCE for the industrial and commercial use as a
processing aid for battery separator manufacturing. The primary
alternative regulatory action differs from the proposed regulatory
action in that it extends the compliance date for the exemption by five
years, allowing a longer timeframe for stakeholders to continue the use
until its prohibition, in recognition of the challenge to transition to
an alternative chemical or process, further discussed in Unit V.B. The
conditions for the exemption under the primary alternative regulatory
action would be: (1) The use of TCE would be limited to use as a
processing aid for battery separator manufacturing to supply the
essential battery components to continue to support the national
economy, national security, and critical infrastructure; (2) this
specific industrial and commercial use of TCE as a processing aid must
be conducted at industrial facilities already using TCE to supply the
lithium ion or lead acid battery components; and (3) Industry
stakeholders who use TCE as a processing aid for battery separator
manufacturing and entities that manufacture (including import),
process, and distribute in commerce TCE to be available as a processing
aid must comply with the WCPP requirements described in Unit V.B.2.,
including meeting the ECEL to the extent possible until the prohibition
compliance date.
ii. Primary Alternative 30-Year Exemption for Industrial and Commercial
Use of TCE in Laboratory Use for Essential Laboratory Activities
    As part of the primary alternative regulatory action, based on the
analysis discussed in Unit V.A.3.a.iii., there would be a 30-year
exemption from the prohibition on TCE in other miscellaneous industrial
and commercial use of TCE in laboratory use for essential laboratory
activities. The primary alternative regulatory action differs from the
proposed regulatory action in that it shortens the compliance date by
20 years. The conditions for the primary alternative proposed exemption
are: (1) The use of TCE is limited to uses in an industrial or
commercial laboratory for essential laboratory activities, including
chemical analysis, chemical synthesis, extracting and purifying other
chemicals, dissolving other substances, with the exclusion of
laboratory testing for asphalt; and (2) Stakeholders who use TCE in
laboratory settings and stakeholders who manufacture (including
import), process, and distribute in commerce TCE to be available as a
laboratory chemical must comply with the WCPP requirements described in
Unit V.B.2., including meeting the ECEL to the extent possible until
the prohibition compliance date.
iii. Primary Alternative Seven-Year Exemption for Industrial and
Commercial Use of TCE in Batch Vapor Degreasing for Essential Aerospace
Parts and Components and Narrow Tubing Used in Medical Devices
    For the reasons discussed in this unit, EPA would grant a seven-
year exemption from the prohibition as part of the primary alternative
regulatory action for the industrial and commercial use of TCE in batch
vapor degreasing for essential aerospace parts and components and
narrow tubing used in medical devices. While one requester suggested
that an appropriate length of time for an exemption would be 10 years,
and another did not specify, EPA notes that a prohibition on vapor
degreasing with TCE for all uses was proposed in 2017 (Ref. 68). While
that proposal was withdrawn pending the completion of a risk evaluation
for TCE under amended TSCA, which included the evaluation of the vapor
degreasing conditions of use, EPA expects that certain stakeholders
have made significant progress on substitutes since then in
anticipation of similar restrictions on TCE under amended TSCA. For
instance, EPA is aware that many users have transitioned to a
substitute for TCE where possible or are planning for technologically
feasible adjustments (Refs. 32, 43).
    The conditions for the exemption would be: (1) TCE could only be
used for batch vapor degreasing of aerospace parts or components
(including rayon fabric) where other alternatives present technical
feasibility or cleaning performance challenges to meet specifications
from other Federal agencies or other long-standing design
specifications that are included in existing contracts, or for batch
vapor degreasing of narrow tubing used in medical devices; and (2)
Industry stakeholders who use TCE for batch vapor degreasing of
aerospace parts or components or narrow tubing used in medical devices
and entities that manufacture (including import), process, and
distribute in commerce TCE to be available for TCE vapor degreasing
would comply with the WCPP requirements described in Unit V.B.2. to the
extent possible until the prohibition compliance date. EPA requests
comments on all aspects of the exemption request and the exemption in
the primary alternative regulatory action from the prohibition on use
of TCE in batch vapor degreasing, including whether compliance with the
WCPP should also be required during the period of the exemption.
Additionally, EPA is soliciting comment on whether

it should specify the type of batch vapor degreasing operation, such as
open-top or closed loop batch vapor degreasing, that would be exempt
from prohibition as part of the primary alternative regulatory action
for the industrial and commercial use of TCE in batch vapor degreasing
for essential aerospace parts and components and narrow tubing for
medical devices. EPA also requests comment whether it should consider
different exemption timeframes for different types of vapor degreasing
operations.
iv. Primary Alternative 15-Year TSCA Section 6(G)(1)(A) Exemption for
Industrial and Commercial Use of TCE as a Processing Aid for Specialty
Polymeric Microporous Sheet Materials
    As part of the primary alternative regulatory action, based on the
analysis in Unit V.A.3.c., EPA would grant a 15-year exemption from the
prohibition on TCE for the industrial and commercial use as a
processing aid for specialty polymeric microporous sheet material
manufacturing. Under the primary alternative regulatory action, in
accordance with TSCA section 6(g)(4), the conditions for the exemption
that EPA believes are necessary to protect health and the environment
would be: (1) The use of TCE would be limited to use as a processing
aid for the manufacturing of specialty polymeric microporous sheet
materials; and (2) Stakeholders who use TCE as a processing aid for the
manufacturing of specialty polymeric microporous sheet materials and
entities that manufacture (including import), process, and distribute
in commerce TCE to be available as a processing aid must comply with
the WCPP requirements described in Unit V.B.2., including meeting the
ECEL to the extent possible until the prohibition compliance date. EPA
requests comments on all aspects of the exemption in the primary
alternative regulatory action from the prohibition on industrial and
commercial use of TCE as a processing aid, specific to the
manufacturing of specialty microporous sheet materials, including
whether compliance with the WCPP should also be required during the
period of the exemption. EPA also requests comment on whether 15 years
would be an appropriate timeframe for a TSCA section 6(g)(1)(A)
exemption for this use.

C. Overview of Conditions of Use and Proposed Regulatory Action and
Primary Alternative Regulatory Action

    Table 2 is a side-by-side depiction of the proposed regulatory
action with the primary alternative action for each condition of use
identified as driving the unreasonable risk (Ref. 2). The purpose of
this table is to succinctly convey to the public the major differences
between the proposed regulatory action and the primary alternative
regulatory action; as such the actions in each column are truncated and
do not necessarily reflect all the details of the proposed and
alternative regulatory action, including differences in timeframes. EPA
notes that ``prohibit + WCPP'' listed in the table indicates that a
condition of use would be prohibited, but in the time before the
prohibition goes into effect, there would be a WCPP. For the proposed
action, the WCPP would include an ECEL of 0.0011 ppm based on the fetal
cardiac defects endpoint so that the developing fetus is best protected
(see Unit V.A.), especially for the sensitive PESS group of older
pregnant workers and ONUs (the group identified as most susceptible to
fetal cardiac defects), while under the primary alternative regulatory
action, the WCPP would include an ECEL of 0.0040 ppm based on the
immunotoxicity endpoint (see Unit V.B.). The rationale for these
differences is detailed in Unit VI.A.1.
    The proposed and alternative regulatory actions are described more
fully in Units V.A. and B.

     Table 2--Overview of Proposed Regulatory Action and Alternative
                 Regulatory Action by Conditions of Use
------------------------------------------------------------------------
                                                Action
                             -------------------------------------------
      Condition of use         Proposed regulatory   Primary alternative
                                   action \1\              action
------------------------------------------------------------------------
Manufacturing: domestic       Prohibit + WCPP       Prohibit + WCPP
 manufacture.                  includes an ECEL of   includes an ECEL of
                               0.0011 ppm for        0.0040 ppm for
                               inhalation            inhalation
                               exposures to TCE as   exposures to TCE as
                               an eight-hour TWA     an eight-hour TWA
                               based on              based on
                               developmental         immunotoxicity.
                               toxicity.
Manufacturing: import.......  Prohibit + WCPP       Prohibit + WCPP
                               includes an ECEL of   includes an ECEL of
                               0.0011 ppm for        0.0040 ppm for
                               inhalation            inhalation
                               exposures to TCE as   exposures to TCE as
                               an eight-hour TWA     an eight-hour TWA
                               based on              based on
                               developmental         immunotoxicity.
                               toxicity.
Processing: processing as a   Prohibit; includes a  Prohibit; includes a
 reactant/intermediate.        phaseout of TCE for   phaseout of TCE for
                               processing as an      processing as an
                               intermediate for      intermediate for
                               the manufacture of    the manufacture of
                               HFC-134a + WCPP       HFC-134a + WCPP
                               includes an ECEL of   includes an ECEL of
                               0.0011 ppm for        0.0040 ppm for
                               inhalation            inhalation
                               exposures to TCE as   exposures to TCE as
                               an eight-hour TWA     an eight-hour TWA
                               based on              based on
                               developmental         immunotoxicity.
                               toxicity.
Processing: incorporation     Prohibit + WCPP       Prohibit + WCPP
 into a formulation,           includes an ECEL of   includes an ECEL of
 mixture, or reaction          0.0011 ppm for        0.0040 ppm for
 product.                      inhalation            inhalation
                               exposures to TCE as   exposures to TCE as
                               an eight-hour TWA     an eight-hour TWA
                               based on              based on
                               developmental         immunotoxicity.
                               toxicity.
Processing: incorporation     Prohibit............  Prohibit.
 into articles.
Processing: repackaging.....  Prohibit + WCPP       Prohibit + WCPP
                               includes an ECEL of   includes an ECEL of
                               0.0011 ppm for        0.0040 ppm for
                               inhalation            inhalation
                               exposures to TCE as   exposures to TCE as
                               an eight-hour TWA     an eight-hour TWA
                               based on              based on
                               developmental         immunotoxicity.
                               toxicity.
Processing: recycling.......  Prohibit + WCPP       Prohibit + WCPP
                               includes an ECEL of   includes an ECEL of
                               0.0011 ppm for        0.0040 ppm for
                               inhalation            inhalation
                               exposures to TCE as   exposures to TCE as
                               an eight-hour TWA     an eight-hour TWA
                               based on              based on
                               developmental         immunotoxicity.
                               toxicity.

Industrial and commercial     Prohibit............  Prohibit; includes a
 use as a solvent for open-                          TSCA section 6(g)
 top batch vapor degreasing.                         exemption for the
                                                     industrial and
                                                     commercial use as
                                                     solvent for open-
                                                     top batch vapor
                                                     degreasing for
                                                     essential aerospace
                                                     use + WCPP includes
                                                     an ECEL of 0.0040
                                                     ppm for inhalation
                                                     exposures to TCE as
                                                     an eight-hour TWA
                                                     based on
                                                     immunotoxicity.
Industrial and commercial     Prohibit; includes a  Prohibit; includes a
 use as a solvent for closed-  phaseout of TCE for   TSCA section 6(g)
 loop batch vapor degreasing.  industrial and        exemption for the
                               commercial use as a   industrial and
                               solvent for closed    commercial use as
                               loop batch vapor      solvent for closed-
                               degreasing for        loop batch vapor
                               rayon fabric          degreasing for
                               scouring for end      essential aerospace
                               use rocket booster    use and medical
                               nozzle production     tubing + WCPP
                               by Federal Agencies   includes an ECEL of
                               and their             0.0040 ppm for
                               contractors and a     inhalation
                               TSCA section 6(g)     exposures to TCE as
                               exemption for         an eight-hour TWA
                               industrial and        based on
                               commercial use as a   immunotoxicity.
                               solvent for closed
                               loop batch vapor
                               degreasing
                               necessary for human-
                               rated rocket engine
                               cleaning by NASA
                               and its
                               contractors+ WCPP
                               for one sub-use
                               includes an ECEL of
                               0.0011 ppm for
                               inhalation
                               exposures to TCE as
                               an eight-hour TWA
                               based on
                               developmental
                               toxicity.
Industrial and commercial     Prohibit............  Prohibit.
 use as a solvent for in-
 line conveyorized vapor
 degreasing.
Industrial and commercial     Prohibit............  Prohibit.
 use as a solvent for in-
 line web cleaner vapor
 degreasing.
Industrial and commercial     Prohibit............  Prohibit.
 use as a solvent for cold
 cleaning.
Industrial and commercial     Prohibit............  Prohibit.
 use as a solvent for
 aerosol spray degreaser/
 cleaner and mold release.
Industrial and commercial     Prohibit............  Prohibit.
 use as a lubricant and
 grease in tap and die fluid.
Industrial and commercial     Prohibit............  Prohibit.
 use as a lubricant and
 grease in penetrating
 lubricant.
Industrial and commercial     Prohibit............  Prohibit.
 use as an adhesive and
 sealant in solvent-based
 adhesives and sealants;
 tire repair cement/sealer;
 mirror edge sealant.
Industrial and commercial     Prohibit............  Prohibit.
 use as a functional fluid
 in heat exchange fluid.
Industrial and commercial     Prohibit............  Prohibit.
 use in paints and coatings
 as a diluent in solvent-
 based paints and coatings.
Industrial and commercial     Prohibit............  Prohibit.
 use in cleaning and
 furniture care products in
 carpet cleaner and wipe
 cleaning.
Industrial and commercial     Prohibit............  Prohibit.
 use in laundry and
 dishwashing products in
 spot remover.
Industrial and commercial     Prohibit............  Prohibit.
 use in arts, crafts, and
 hobby materials in
 fixatives and finishing
 spray coatings.
Industrial and commercial     Prohibit............  Prohibit.
 use in corrosion inhibitors
 and anti-scaling agents.
Industrial and commercial     Prohibit; includes a  Prohibit; includes
 use as a processing aid for   TSCA section 6(g)     TSCA section 6(g)
 battery separator             exemption for the     exemptions for the
 manufacturing and for the     industrial and        industrial and
 manufacturing of specialty    commercial use as a   commercial use as a
 polymeric microporous sheet   processing aid for    processing aid for
 materials; process solvent    battery separator     battery separator
 used in polymer fabric        manufacturing +       manufacturing and
 spinning, fluoroelastomer     WCPP includes an      for the
 manufacture and Alcantara     ECEL of 0.0011 ppm    manufacturing of
 manufacture; extraction       for inhalation        specialty polymeric
 solvent used in caprolactam   exposures to TCE as   microporous sheet
 manufacture; precipitant      an eight-hour TWA     materials + WCPP
 used in beta-cyclodextrin     based on              includes an ECEL of
 manufacture.                  developmental         0.0040 ppm for
                               toxicity.             inhalation
                                                     exposures to TCE as
                                                     an eight-hour TWA
                                                     based on
                                                     immunotoxicity.
Industrial and commercial     Prohibit............  Prohibit.
 use as ink, toner and
 colorant products in toner
 aid.
Industrial and commercial     Prohibit............  Prohibit.
 use in automotive care
 products in brake parts
 cleaner.

Industrial and commercial     Prohibit............  Prohibit.
 use in apparel and footwear
 care products in shoe
 polish.
Industrial and commercial     Prohibit; includes a  Prohibit; includes a
 use in hoof polish; gun       TSCA section 6(g)     TSCA section 6(g)
 scrubber; pepper spray;       exemption for the     exemption for the
 other miscellaneous           industrial and        industrial and
 industrial and commercial     commercial use as a   commercial use as a
 uses.                         laboratory chemical   laboratory chemical
                               for essential         for essential
                               laboratory            laboratory
                               activities and some   activities + WCPP
                               research and          includes an ECEL of
                               development           0.0040 ppm for
                               activities + WCPP     inhalation
                               includes an ECEL of   exposures to TCE as
                               0.0011 ppm for        an eight-hour TWA
                               inhalation            based on
                               exposures to TCE as   immunotoxicity.
                               an eight-hour TWA
                               based on
                               developmental
                               toxicity.
Consumer use as a solvent in  Prohibit \2\........  Prohibit.\2\
 brake and parts cleaners.
Consumer use as a solvent in  Prohibit \2\........  Prohibit.\2\
 aerosol electronic
 degreaser/cleaner.
Consumer use as a solvent in  Prohibit \2\........  Prohibit.\2\
 liquid electronic degreaser/
 cleaner.
Consumer use as a solvent in  Prohibit \2\........  Prohibit.\2\
 aerosol spray degreaser/
 cleaner.
Consumer use as a solvent in  Prohibit \2\........  Prohibit.\2\
 liquid degreaser/cleaner.
Consumer use as a solvent in  Prohibit \2\........  Prohibit.\2\
 aerosol gun scrubber.
Consumer use as a solvent in  Prohibit \2\........  Prohibit.\2\
 liquid gun scrubber.
Consumer use as a solvent in  Prohibit \2\........  Prohibit.\2\
 mold release.
Consumer use as a solvent in  Prohibit \2\........  Prohibit.\2\
 aerosol tire cleaner.
Consumer use as a solvent in  Prohibit \2\........  Prohibit.\2\
 liquid tire cleaner.
Consumer use as a lubricant   Prohibit \2\........  Prohibit.\2\
 and grease in tap and die
 fluid.
Consumer use as a lubricant   Prohibit \2\........  Prohibit.\2\
 and grease in penetrating
 lubricant.
Consumer use as an adhesive   Prohibit \2\........  Prohibit.\2\
 and sealant in solvent-
 based adhesives and
 sealants.
Consumer use as an adhesive   Prohibit \2\........  Prohibit.\2\
 and sealant in mirror edge
 sealant.
Consumer use as an adhesive   Prohibit \2\........  Prohibit.\2\
 and sealant in tire repair
 cement/sealer.
Consumer use as a cleaning    Prohibit \2\........  Prohibit.\2\
 and furniture care product
 in carpet cleaner.
Consumer use as a cleaning    Prohibit \2\........  Prohibit.\2\
 and furniture care product
 in aerosol spot remover.
Consumer use as a cleaning    Prohibit \2\........  Prohibit.\2\
 and furniture care product
 in liquid spot remover.
Consumer use in arts,         Prohibit \2\........  Prohibit.\2\
 crafts, and hobby materials
 in fixative and finishing
 spray coatings.
Consumer use in apparel and   Prohibit \2\........  Prohibit.\2\
 footwear products in shoe
 polish.
Consumer use in fabric spray  Prohibit \2\........  Prohibit.\2\
Consumer use in film cleaner  Prohibit \2\........  Prohibit.\2\
Consumer use in hoof polish.  Prohibit \2\........  Prohibit.\2\
Consumer use in toner aid...  Prohibit \2\........  Prohibit.\2\
Disposal to industrial pre-   Prohibit the          Prohibit.
 treatment, industrial         disposal of TCE to
 treatment, or publicly        industrial pre-
 owned treatment works.        treatment,
                               industrial
                               treatment, or
                               publicly owned
                               treatment works;
                               with a TSCA section
                               6(g) exemption for
                               the disposal of TCE
                               from cleanup
                               projects.
------------------------------------------------------------------------
\1\ Does not include exemptions under TSCA section 6(g); for certain
  industrial and commercial uses of TCE for DoD naval vessels and their
  systems, and in the maintenance, fabrication, and sustainment for and
  of such vessels and systems + WCPP, which includes an ECEL of 0.0011
  ppm for inhalation exposures to TCE as an eight-hour TWA based on
  developmental toxicity; or for the emergency industrial and commercial
  use of TCE in furtherance of the NASA mission for specific conditions
  that are critical or essential and for which no technically and
  economically feasible safer alternative is available + WCPP, which
  includes an ECEL of 0.0011 ppm for inhalation exposures to TCE as an
  eight-hour TWA based on developmental toxicity.
\2\ Prohibit manufacture, processing, and distribution in commerce for
  the consumer use.

VI. Rationale for the Proposed Regulatory Action and Primary
Alternative Regulatory Action

    This unit describes how the considerations described in Unit
III.B.3. were applied when selecting among the TSCA section 6(a)
requirements to arrive at the proposed and primary alternative
regulatory actions described in Unit V.

A. Consideration of Risk Management Requirements Available Under TSCA
Section 6(a)

1. Proposed Regulatory Action
a. Prohibition
    EPA considered a prohibition as a regulatory option and is
proposing it for all manufacturing (including import), processing,
distribution in commerce, use, and certain types of disposal of TCE
(Unit V.A.). EPA proposes that prohibition is necessary to address the
unreasonable risk for all occupational conditions of use after taking
into consideration other combinations of controls such as a non-
prescriptive WCPP or prescriptive controls (i.e., engineering controls,
administrative controls, and PPE). As described in Unit V.A., EPA's
bases for the need for this regulatory approach are similar to those
for the Agency's determination of unreasonable risk, and include
severity of the hazard, exposed populations, magnitude of risk, and
uncertainties (Ref. 2). Throughout this proposed rule, EPA has
described the severity of the hazard of TCE (including immunotoxicity,
developmental, and cancer risks), based on the 2020 Risk Evaluation for
TCE, as well as the populations exposed to the 52 conditions of use
that drive the unreasonable risk, which include numerous workers, ONUs,
consumers, and bystanders, including PESS such as workers of
reproductive age (in particular, older pregnant women).
    The significance of the magnitude of exposures for TCE is
highlighted when considering the margins of exposure (MOEs, or the
health point of departure for an endpoint divided by the exposure
concentration) in the risk evaluation that estimate non-cancer risk for
acute and chronic exposure. Estimated MOEs are compared to a benchmark,
described in more detail in the risk evaluation, as part of the
unreasonable risk determination (Refs. 1, 2). An MOE lower than the
benchmark supports a determination of unreasonable risk of injury to
health, based on noncancer effects. As an example, for commercial use
of TCE in open top vapor degreasing, the chronic MOE for fetal cardiac
defects is 0.0006, which is several orders of magnitude lower than then
benchmark of 10. Even with engineering controls, the only way to reduce
exposures more than 1,000-fold would be PPE with an APF of 10,000 (Ref.
1). This level of APF would require workers to constantly wear a full-
face self-contained breathing apparatus (SCBA) in pressure demand mode
or other positive pressure mode, which is considered unsustainable for
the long-term and the least preferred approach to worker protection in
the hierarchy of controls. There are many documented limitations to
successful implementation of respirators with an APF of 10,000,
including difficulties in fit and use rendering them ineffective in
actual application, preventing the assurance of consistent and reliable
protection, regardless of the assigned capabilities of the respirator
(Refs. 69, 70) (63 FR 1152, January 8, 1998). EPA requests comments on
subsections of conditions of use, which by nature of their infrequent
occurrence, could meet the ECEL without having their employees wear
high APF levels of PPE on a daily basis. Given that the magnitude of
risk from TCE is so high, and that the extremely high level of PPE
would be an ineffective long-term way of addressing that risk along
with information provided by stakeholders, including during
consultations (Refs. 70, 31), EPA has significant uncertainty that any
measures short of prohibition would be sufficient to address the
unreasonable risk. Therefore, EPA proposes that prohibition is the
preferred option to ultimately address unreasonable risk. EPA believes
that the extremely low ppm level of the ECEL, while fully addressing
unreasonable risk, will be infeasible for industry to reliably meet due
to the need for a combination of engineering, administrative controls,
and full-face, self-contained, air-supplied respirators. As such, the
only way to protect human health consistently, reliably, and
continually from unreasonable risk would be to prohibit TCE.
    Ultimately, a prohibition would result in elimination of
unreasonable risk from TCE, rather than allowing TCE use to continue in
perpetuity, which would necessitate burdensome requirements to achieve
exposure reductions to implement a technically challenging long-term
program to meet a very low exposure limit. Recognizing that longer
compliance timeframes and TSCA section 6(g) time-limited exemptions
would nevertheless be necessary for certain critical uses to continue
for a period of time as, described previously in Units V.A.1.d.,
V.A.1.e., and V.A.1.f., it is necessary to protect workers, including
PESS, such as older pregnant workers and ONUs (the group identified as
most susceptible to fetal cardiac defects). Therefore, as described in
Unit IV., EPA is proposing the WCPP ECEL of 0.0011 ppm, based on the
fetal cardiac defects endpoint, so that the developing fetus is best
protected. EPA's primary alternative regulatory option bases the WCPP
ECEL for TCE on the immunotoxicity endpoint. Because it would not be as
protective for the subset of PESS that include older pregnant workers
and ONUs as specific under TSCA section 6(b), the ECEL based on
immunotoxicity was not put forth as the proposed ECEL. In other words,
under the immunotoxicity ECEL of 0.0040 ppm, workers and ONUs would be
protected from immunosuppression resulting from an acute (eight-hour)
exposure, and from an excess risk of cancer resulting from lifetime
exposure, as well as other adverse health effects such as reproductive
toxicity, liver toxicity, kidney toxicity, and neurotoxicity. When the
ECEL of 0.0011 ppm based on fetal cardiac defects is used, EPA expects
that a fetus would be protected from the effects of maternal exposure
by workers and ONUs, in addition to the protections noted previously.
Given this gap in protectiveness, the immunotoxicity ECEL of 0.0040 ppm
is being considered as the alternative regulatory option rather than
the proposed approach. As noted in Unit V.A.2., EPA has significant
uncertainty about the extent to which some members of the regulated
community could measure or reliably meet either the ECEL of 0.0011 ppm
(in the proposed WCPP) or the ECEL of 0.0040 ppm (in the primary
alternative regulatory action), which contributes to EPA's proposal
that prohibition is the best long-term risk management option for TCE.
    EPA understands that additional time may be necessary for certain
processing and industrial and commercial conditions of use to achieve a
full prohibition, including the need for upstream manufacturing,
processing, and distribution in commerce for those uses to continue to
ensure availability for the supply chain. In particular, EPA recognizes
that processing TCE as a reactant/intermediate often takes place in
unique closed-systems, and facilities processing TCE may need
additional time to transition to adjust the physical plant design to
accommodate an alternative manufacturing process or chemical substance
and avoid significantly disrupting the supply

chain. For example, EPA understands that the manufacturing (including
import) and processing of TCE as an intermediate for the manufacture of
HFC-134a is expected to phase down (absent a TSCA prohibition) over
time as users move to more climate-friendly alternatives under the
requirements of the AIM Act. In this instance, EPA is proposing
requirements as part of a WCPP to reduce the worker exposures to TCE
until the prohibition compliance date. In addition, EPA recognizes that
industrial and commercial use of TCE as a solvent for closed-loop batch
vapor degreasing for rayon fabric scouring for end use in rocket
booster nozzle production by Federal agencies and their contractors is
a highly specific use with a uniquely long qualification process for
alternatives. In the production of booster rocket nozzles, TCE is used
in vapor degreasing as a solvent in rayon fabric sourcing, an intensive
cleaning process to remove contaminants. This rayon fabric is then
carbonized as part of an ablative process in the nozzle production and
used to line the inside of the nozzles on booster rockets (Ref. 43).
Cleaning is a critical step of this process; if contaminants are not
sufficiently removed in the scouring stage, the fabric will be degraded
during the chemical reaction that occurs during carbonization, which
could result in failure of the nozzle during a launch and catastrophic
effects for the rockets.
    For this use, NASA has presented information to EPA on the
necessity of additional time to transition to an alternative, given
that 8 rocket launches are planned using booster sets with a component
produced with TCE (Ref. 43). These launches could not occur if
prohibition occurred on a shorter timeframe. In particular, given the
end use of the components in human-rated spaceflight, EPA recognizes
that NASA must conduct an array of tests to qualify an alternative
solvent to TCE, including a variety of booster rocket function tests
culminating in a full-scale static motor test. Even if an alternative
were identified and qualified through a successful testing cycle,
additional time would be needed for updates to workflows and production
of new booster nozzles (Ref. 43). As such, EPA has provided additional
time for the industrial and commercial use as a solvent for closed-loop
batch vapor degreasing for rayon fabric scouring for end use in rocket
booster nozzle production by Federal agencies and their contractors.
EPA recognizes that other Federal agencies may also rely on rayon
fabric scouring for their rocket booster nozzle production and so
proposes that the phaseout for this sub-set of the industrial and
commercial use of TCE as a solvent in closed-loop batch vapor
degreasing apply to Federal agencies generally and their contractors.
As a condition for the phaseout, EPA has specified that a final pre-
launch test of rocket booster nozzles without using TCE must be
conducted within 5 years, with a full prohibition in 10 years on the
use of TCE in scouring rayon fabric for end use in nozzles in rocket
boosters. For this phaseout period, EPA is proposing requirements as
part of a WCPP to reduce the worker exposures to TCE until the
prohibition compliance date, and Unit V.A.2. explains that the
establishment of a WCPP is intended to allow more flexibility to
regulated entities than requiring specific prescriptive controls.
Similarly, EPA is proposing the WCPP to reduce to the extent possible
the unreasonable risk until the prohibition compliance date for certain
conditions of use that would be permitted to continue for longer than a
year after publication of the final rule, as discussed in Unit V.A.
    Additionally, prohibition is the preferred option for occupational
conditions of use where reasonably available information suggests
minimal ongoing use or when feasible safer alternatives are reasonably
available. As described in this unit, EPA is highly uncertain as to
whether users could comply with the requirements of a TCE WCPP, and EPA
is also concerned with the severity of the risks of TCE. EPA notes the
prevalence of alternative processes and products (Unit VI.B.). In some
cases, reasonably available information indicating a use is no longer
ongoing (Refs. 71, 3), has led EPA to propose more immediate
prohibitions for most industrial and commercial uses of TCE, including
the upstream manufacturing, processing, and distribution in commerce
for those uses. EPA requests public comment on the rationale for
proposing prohibitions as the preferred risk management approach. In
addition, EPA requests comment regarding the number of businesses and
other entities that could potentially close as well as associated costs
with a prohibition of TCE for the industrial and commercial conditions
of use identified in Unit V.A.1.
    TSCA section 6(a)(2) provides EPA with the authority to prohibit or
otherwise restrict the manufacture (including import), processing, or
distribution in commerce of a substance or mixture ``for a particular
use'' to ensure that a chemical substance no longer presents
unreasonable risk. For this rulemaking, EPA proposes that ``for a
particular use'' include consumer use, which encompasses all known,
intended, and reasonably foreseen consumer uses for TCE (Ref. 1). Given
the severity and ubiquitous nature of the risks identified in the 2020
Risk Evaluation for TCE for processing of TCE into formulation as well
as for all but one consumer use (pepper spray) and, noting that those
conditions of use encompass all known, intended, and reasonably
foreseen consumer use, EPA proposes that prohibiting manufacture
(including importing), processing, and distribution in commerce of TCE
for consumer use is reasonable and necessary to address the
unreasonable risk from TCE driven by manufacturing (including
importing) and processing TCE into formulation (the upstream conditions
of use for products intended for consumer use), and that this proposed
approach will also address the unreasonable risk to consumers and
bystanders. Furthermore, amongst the broad prohibition of TCE, EPA
considered and acknowledges the likely future unavailability of TCE for
the consumer use of pepper spray, and EPA expects the prohibition on
industrial and commercial use of TCE in pepper spray, as well as the
upstream prohibition on manufacturing, processing, and distribution of
TCE for commercial or consumer uses, would result in no TCE-containing
pepper spray being produced for consumer use (Ref. 71).
    Details of the proposed prohibitions are described in more detail
in Unit V.A.
b. Workplace Chemical Protection Program (WCPP)
    i. Overall. Prohibition is the preferred option for all
occupational COUs, because significant uncertainty exists relative to
any sector's ability to comply with a notably low exposure limit for
TCE, particularly given the magnitude of exposure for many conditions
of use (see Unit V.A.1.). A more immediate prohibition is the preferred
option for occupational conditions of use where greater uncertainty
exists relative to a sector's ability to comply with provisions of a
WCPP, in particular a very low ECEL, as well as additional requirements
that would support implementation of these restrictions (described in
Unit V.A.2.). The 8-hour TWA ECEL of 0.0011 ppm for TCE that EPA is
proposing, based on the developmental toxicity endpoint, is
significantly lower than the OSHA PEL of 100 ppm, and there is a high
degree of uncertainty as to whether users under the conditions of use
in any sector would be able to comply with such a level and, thus,
whether the

unreasonable risk would be addressed. However, to address, to the
extent possible, the unreasonable risk during the time period before a
prohibition would become effective, EPA is proposing a WCPP until the
prohibition compliance date. The WCPP would include a combination of
restrictions to reduce the unreasonable risk from TCE driven by
inhalation and dermal exposures in the workplace until the prohibition
compliance date and is proposed only for certain conditions of use. EPA
requests public comment related to the ability of regulated entities to
meet the ECEL of 0.0011 ppm, and whether EPA should prescribe mandatory
restrictions and PPE levels.
    ii. Existing Chemical Exposure Limit. One requirement considered by
EPA to include in a TCE WCPP to reduce the unreasonable risk driven by
inhalation exposures to TCE for occupational conditions of use was
establishing an ECEL and related implementation measures, such as
exposure monitoring, until the prohibition compliance date. As
described in Unit V.A., the TCE WCPP would be non-prescriptive, in the
sense that regulated entities would not be required to use specific
controls prescribed by EPA to achieve the exposure concentration limit.
Rather, it would be a performance-based exposure limit that would
enable owners or operators to determine how to most effectively put
measures in place to reduce the exposure to TCE based on conditions at
their workplace, consistent with the hierarchy of controls.
    A central component of the TCE WCPP is the exposure limit.
Exposures remaining at or below the ECEL would address any unreasonable