the GHS Rev. 7 (UN GHS, 2017, Document ID 0060). The only modification
that OSHA proposes making to the GHS Table 2.2.1 is to add units of
measurement used in the United States (e.g., degrees Fahrenheit). Under
the proposed new table, all flammable gases that are currently
classified as Category 1 flammable gases would be classified as
Category 1A, unless data on flammability limit or fundamental burning
velocity indicates that the gas should be classified as Category 1B.
For a gas to be classified in Category 1B, data would have to show that
its lower flammability limit is more than 6% by volume in air or its
fundamental burning velocity is less than 10 cm/s; in addition, the gas
could not be either pyrophoric or chemically unstable. Since the HCS
does not require testing, the data required to classify a gas as a
Category 1B flammable gas could be obtained from literature. However,
if data is lacking in the literature, then testing would be necessary
to establish that a newly-developed flammable gas qualifies for
classification as a Category 1B flammable gas. The joint informal
working group compiled a list of data available on burning velocity and
flammability limits for pure flammable gases (OSHA, 2017, Document ID
0164).
    When OSHA revised the HCS in 2012, pyrophoric gases were not
classified under the GHS, Rev. 3 (UN GHS, 2009, Document ID 0085).
Therefore, to ensure that the hazards of pyrophoric gases would
continue to be covered and communicated, OSHA maintained the approach
taken in the HCS starting in 1994. This involved addressing pyrophoric
gases under the definition of ``hazardous chemical'' and maintaining a
definition for ``pyrophoric gas'' in paragraph (c) of the HCS (77 FR
17704). While OSHA retained the definition for ``pyrophoric gas'' when
it updated the HCS in 2012, the agency explained it also intended to
continue to work with the UNSCEGHS to add the pyrophoric gas hazard to
the GHS, along with two other hazards that OSHA covered under the HCS
but that were not classified under the GHS: Simple asphyxiants and
combustible dust (77 FR 17704). Since OSHA revised the HCS in 2012, the
UNSCEGHS updated the criteria for flammable gases to include pyrophoric
gases (UN GHS, 2014, Document ID 0086; UN GHS, 2017, Document ID 0060).
The UNSCEGHS agreed that pyrophoric gases, as well as chemically
unstable gases, should always be classified as Category 1A flammable
gases because of the nature of these two types of gases; pyrophoric
gases ignite spontaneously in air at temperatures of 54 [deg]C (130
[deg]F) or below, and chemically unstable gases are able to react
explosively even in the absence of air or oxygen. Under the GHS Rev. 7
(UN GHS, 2017, Document ID 0060), pyrophoric gases and chemically
unstable gases are both classified as Category 1A. OSHA preliminarily
agrees with this decision and proposes incorporating it into appendix
B.2.
    If, as proposed, OSHA adds pyrophoric gases as a sub-category of
flammable gases in appendix B.2, and, as proposed, includes a
definition of pyrophoric gas in appendix B.2., it would no longer be
necessary to include these gases as part of the definition of
``hazardous chemical'' or to include a definition for ``pyrophoric
gas'' in Sec.  1910.1200(c). Therefore, OSHA proposes to delete those
terms in Sec.  1910.1200(c). OSHA also proposes to incorporate the
definition of ``pyrophoric gas'' found in the GHS Rev. 7 (UN GHS, 2017,
Document ID 0060), in paragraph B.2.1. OSHA currently defines
pyrophoric gas as a chemical in the gaseous state that ``will ignite''
spontaneously in air at a temperature of 130 [deg]F (54.4 [deg]C) or
below. The GHS Rev. 7 defines a pyrophoric gas as a flammable gas that
is ``liable to ignite'' spontaneously in air at a temperature of 54
[deg]C (130 [deg]F) or below (UN GHS, 2017, Document ID 0060). The
change in the definition from a gas that ``will ignite'' to a gas that
is ``liable to ignite'' was made because some pyrophoric gases may have
a delayed ignition time (UN GHS, 2013, Document ID 0086). OSHA
preliminarily finds the term ``liable to ignite'' to be more accurate,
from a technical perspective. OSHA does not believe that these changes
would have a significant impact on the scope of

gases considered pyrophoric gases, nor does OSHA expect that chemical
manufacturers or importers would need to reclassify chemicals due to
these changes.
    As noted above, OSHA proposes adding a new sub-category for
chemically unstable gases to the flammable gases hazard class to allow
for more accurate communication of the hazards associated with those
gases. OSHA proposes to adopt the GHS Rev. 7 definition of a chemically
unstable gas, i.e., a flammable gas that is able to react explosively
even in the absence of air or oxygen (UN GHS, 2017, Document ID 0060),
in paragraph B.2.1. Consistent with the GHS Rev. 7 (UN GHS, 2017,
Document ID 0060), under proposed Table B.2.1, a Category 1A chemically
unstable gas would be further sub-characterized into one of two
categories based on the temperature and pressure at which it becomes
unstable. The proposed criteria for Category 1A/A chemically unstable
gases are flammable gases which are chemically unstable at 20 [deg]C
(680 [deg]F) and a standard pressure of 101.3 kPa (14.7 psi). The
proposed criteria for Category 1A/B chemically unstable gases are
flammable gases which are chemically unstable at a temperature greater
than 20 [deg]C (680 [deg]F) and/or a pressure greater than 101.3 kPa
(14.7 psi).
    As chemically unstable gas is a subcategory of flammable gases, any
chemical that meets the criteria for chemically unstable gas meets the
current definition of flammable gas. While these hazards are currently
classified in flammable gases under the HCS the UNSCEGHS noted that
these gases exhibit slightly different behaviors and have the
propensity to react dangerously even in the absence of any reaction
partner (e.g., air or oxygen) and should have different hazard
communication elements (UN GHS, 2010, Document ID 0210). Types of
flammable gases or gas mixtures that might be candidates for
classification as chemically unstable are flammable gases with
functional groups such as triple-bonds, adjacent or conjugated double-
bonds, halogenated double-bonds, and strained rings (UN GHS, 2010,
Document ID 0210). Because chemical manufacturers are currently
classifying chemically unstable gases as flammable gases, OSHA does not
consider these gases to be a new hazard. Instead, OSHA believes the
addition of chemically unstable gases as a separate category in the
appendix for flammable gases (appendix B.2) would improve the way the
hazards of these gases are identified, evaluated, and communicated.
    The GHS Rev. 7 (UN GHS, 2017, Document ID 0060) added three
clarifying notes under Table 2.2.1 that were not included in the GHS
Rev. 3 (UN GHS, 2009, Document ID 0085). The notes provide guidance on
the classification of flammable gases under the new hazard categories.
OSHA is proposing to add these notes to the HCS following Table B.2.1
(as new Note 2, Note 3, and Note 4) because they allow for better
hazard classification.
    The GHS Rev. 7, in Chapter <IP_ADDRESS>, provides additional guidance on
the classification of flammable gases, including the new hazard
categories of pyrophoric gases, chemically unstable gases, and 1B
flammable gases (UN GHS, 2017, Document ID 0060). It includes updated
references to consensus standards and test methods (i.e., ISO
10156:2010), and new references to consensus standards and test methods
related to the new hazard categories (i.e., ISO 817:2014, IEC 60079-20-
1 ed1.0 (2010-01), or DIN 51794, and Part III of UN of the Manual of
Tests and Criteria). OSHA proposes to adopt these changes in the HCS
appendix B.2.3, with edits to make the GHS criteria mandatory (i.e.,
changing ``should'' to ``shall''), to add U.S. units of measurement
(e.g., Fahrenheit), and to add statements that cited standards and test
methods are incorporated by reference under 29 CFR 1910.6. This
proposed modification would also align with the GHS Rev. 7 (UN GHS,
2017, Document ID 0060). However, OSHA does not intend to require those
already classified using an earlier version of ISO 10156, only those
classifying new chemicals or chemicals not already classified. To
incorporate this guidance from the GHS Chapter <IP_ADDRESS>, OSHA is
proposing edits to existing paragraph B.2.3. (B.2.3.1, as proposed) and
new paragraphs B.2.3.2, B.2.3.3, and B.2.3.4.
Aerosols--(Appendix B.3)
    OSHA is proposing to follow the GHS Rev. 7 (UN GHS, 2017, Document
ID 0060) by expanding the existing Flammable Aerosols hazard class
(appendix B.3) to include non-flammable aerosols as well as flammable
ones. Under the GHS Rev. 3 and the current HCS, Chapter 2.3 and
appendix B.3, respectively, were titled ``Flammable Aerosols.'' Under
the GHS Rev. 3, the hazards presented by non-flammable aerosols were
either not classified at all or, more likely, were classified in
another health hazard class or physical hazard class (e.g., gases under
pressure) (UN GHS, 2009, Document ID 0085). Flammable aerosols were
likely to be classified as both flammable aerosols and gases under
pressure.
    OSHA believes that most aerosols are classified as gases under
pressure under the GHS Rev. 3 (and accordingly under the existing HCS)
because of the design criteria of the aerosols (ERG, 2015, Document ID
0163) under DOT regulations. Under DOT regulations, aerosols are non-
refillable receptacles containing a gas compressed, liquefied, or
dissolved under pressure, and the highest permissible pressure is 180
psig at 130 [deg]F (see 49 CFR 171.8, 173.306). Accordingly, under DOT
regulations, most aerosols meet the current HCS criteria for gases
under pressure, which are gases contained in a receptacle at a pressure
of 200 kPa (29 psi) or more, or which are liquefied or liquefied and
refrigerated (see existing paragraph B.5.1 in appendix B.5). However,
OSHA believes that classifying aerosols as gases under pressure may not
accurately identify the hazards of aerosols because aerosol containers
differ from pressurized gas cylinders in terms of container
characteristics and failure mechanisms, as described further below.
    Since the GHS Rev. 3 (UN GHS, 2009, Document ID 0085), the UNSCEGHS
and the UN Sub-committee of Experts on the Transport of Dangerous Goods
(UNSCETDG) agreed to rename Chapter 2.3 ``Aerosols'' and to add a new
non-flammable aerosol hazard category, Category 3, to the aerosols
hazard class (UN GHS, 2018, Document ID 0249). This hazard category
captures aerosols that (1) contain 1% or less flammable components (by
mass); and (2) have a heat of combustion that is less than 20 kJ/g.
    Before proposing to adopt this category for non-flammable aerosols,
OSHA reviewed the impact of this change to ensure that it would not
compromise worker safety and health. OSHA assessed the hazards
associated with aerosol containers and compressed gas cylinders. An ERG
study evaluated how aerosol products and gases under pressure differ in
terms of container characteristics, failure mechanisms, and previous
incidents (ERG, 2015, Document ID 0009).
    The ERG report concluded that sizes and pressures of compressed gas
cylinders far exceed those of hand-held containers typically used for
aerosol products (ERG, 2015, Document ID 0009). The report also noted
differences in failure mechanisms for pressurized cylinders versus
aerosols (ERG, 2015, Document ID 0009). As an example, increased
temperatures can result in the release of container contents from the
activation of pressure relief devices on

cylinders, whereas increased temperatures can result in the bursting of
aerosol cans, which do not contain pressure relief devices. Also,
hazards from falling cylinders include the release of contents
following the valve breaking, the cylinder becoming a projectile or
pinwheel, or the crushing of employees in the area; although aerosol
containers can be damaged if they are dropped or punctured, they do not
pose the same hazards as falling cylinders.
    ERG reported that occupational incidents involving cylinders
included explosions during high temperature activities (such as
welding) and explosions resulting from mechanical deformation (e.g.,
from falling cylinders), over-pressurization of cylinders (e.g., from
overfilling, which can result in a rupture of the cylinder), or leaks
due to corrosion (ERG, 2015, Document ID 0009). Most incidents with
aerosol cans involved explosions following heating or puncture of the
can (ERG, 2015, Document ID 0009). The ERG report concluded that
although non-flammable aerosol cans do not present a significant fire
hazard, they can present a hazard from bursting resulting from thermal
content expansion during heating. (ERG, 2015, Document ID 0009).
    In addition to the ERG report, OSHA also considered data from the
agency's Fatality and Catastrophe Information Summary (FatCat)
database, located at https://www.osha.gov/pls/imis/accidentsearch.html
(Document ID 0204), to evaluate the nature and severity of injuries and
fatalities resulting from the use of aerosols and compressed gases. To
determine if an incident was related to aerosols or compressed gas
cylinders, OSHA searched for the keywords ``aerosol,'' ``spray,'' or
``foam'' (to identify aerosols), and the keywords ``compressed,''
``cylinder,'' or ``CNG'' (to identify compressed gases). The data
reviewed is available in the docket (OSHA, 2019, Document ID 0204).
    From 1995 to 2014 there were more incidents related to the use of
compressed gas cylinders than to the use of aerosol containers, but the
percentage of the incidents that resulted in fatalities was similar
(29% versus 28%, respectively). However, as explained below, fatalities
are more likely to be associated with the container itself when
compressed gas receptacles are in use as compared to situations
involving aerosol containers. (OSHA, 2019, Document 0204).
    Fatalities associated with use of compressed gas cylinders and
aerosol containers primarily fall into three categories: (1) Incidents
due to the contents of the container, such as flash fires or
explosions; (2) incidents due to the container itself, such as
incidents related to pressure, container failure, or ruptures; and (3)
incidents unrelated to the use of the container, such as heart attacks
or falls. A higher percentage of fatalities fell into the second
category (incidents related to the container itself) for compressed gas
cylinders (64% of the compressed gas cylinder fatalities) than for
aerosol containers (17% of the aerosol fatalities). Conversely, a
greater proportion of fatalities related to aerosols were attributed to
reasons other than the container itself (83% for aerosol containers
versus 36% for cylinders) (OSHA, 2019, Document ID 0204). This included
fatalities related to the contents of the container and those in the
third, ``miscellaneous,'' category (where the fatality could not be
directly related to the use of the container, e.g., situations such as
heart attacks, falls, lack of training that occurred while employees
were working with, or that generally related to, the use of aerosol or
compressed gas cylinders) (OSHA, 2019, Document 0204). Thus, it appears
that employees are at greater risk of a fatality due to the failure of
the container if they are working with compressed gas cylinders than
they are if they are working with aerosol cans.
    Following a review of the data and the ERG report, OSHA
preliminarily concludes that a new category for non-flammable aerosols
is appropriate. OSHA believes this category would allow the hazards of
non-flammable aerosols to be more appropriately classified and
communicated, resulting in improved worker protection. The new hazard
category would provide downstream users with more appropriate
communication on the label by adding precautionary statements: Keep
away from heat, hot surfaces, sparks, open flames and other ignition
sources; No smoking; and Do not pierce or burn, even after use (see
appendix C). Additionally, this new classification would ensure
compressed gas pictograms are not included on aerosol labels,
eliminating the risk of ``over warning'' about the hazards of aerosol
containers (UN, 2010, Document ID 0095).
    Specific changes OSHA is proposing include: Updating the aerosol
hazard class to include non-flammable aerosols (hazard Category 3 in
Table B.3.1), changing the name of appendix B.3 from ``Flammable
Aerosols'' to ``Aerosols,'' replacing the phrase ``flammable aerosols''
with ``aerosols'' throughout appendix B.3, as appropriate, and adding
clarifying information from the GHS Rev. 7 to paragraph B.3.2 (UN GHS,
2017, Document ID 0060). For example, OSHA is proposing to revise Note
2 to B.3.2.1 to explain that aerosols do not fall within the scope of
gases under pressure, but may fall within the scope of other hazard
classes. OSHA's preliminarily conclusion that aerosols (flammable and
non-flammable) should not also be classified as gases under pressure
would ensure that the appropriate hazard warnings are presented on
aerosol containers.
    OSHA is proposing to adopt the GHS Rev. 7 (UN GHS, 2017, Document
ID 0060) criteria for a non-flammable aerosol (i.e., an aerosol that
does not meet the criteria for Category 1 or 2, contains less than or
equal to 1 percent flammable components (by mass), and has a heat of
combustion less than 20 kJ/g), and to add those criteria as new
Category 3 in Table B.3.1. This new category, Category 3, would update
hazard communication requirements to better reflect the true hazards of
non-flammable aerosols. This would result in changing the labeling for
any such aerosols that are currently classified as compressed gases. In
these situations, the ``gas cylinder'' pictogram would become
unnecessary, as this hazard class would no longer be considered a
compressed gas, the signal word ``danger'' would change to ``warning,''
due to the decreased hazard, and a hazard statement of ``contains gas
under pressure; may explode if heated'' would change to ``pressurized
container, may burst if heated'', which would more accurately reflect
the hazards associated with this category (see proposed appendix
C.4.16). As discussed above, OSHA believes that this approach would
better differentiate between the hazards associated with compressed
gases and the hazards associated with aerosols.
Oxidizing Gases--(Appendix B.4)
    OSHA proposes to revise the note in B.4.1, and the text in the
``Additional classification considerations'' paragraph at B.4.3, to
clarify that the provisions are referring to the most recent version of
the ISO 10156 standard, (ISO, 10156, 2010). This proposed change would
provide more clarity on the definition and classification of oxidizing
gases and lead to more accurate classification and improved
communication. This proposed modification would also align with the GHS
Rev. 7 (UN GHS, 2017, Document ID 0060). However, OSHA does not intend
to require those already classified using an earlier version of ISO
10156, only those classifying new chemicals or chemicals not already
classified.

Gases Under Pressure--(Appendix B.5)
    OSHA is proposing to change the definition of gases under pressure
in B.5.1 to align with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060).
OSHA proposes to add a temperature of 20 degrees Celsius (68 degrees
Fahrenheit) to the definition so that the full definition would define
gases under pressure as gases which are contained in a receptacle at a
pressure of 200 kPa (29 psi) (gauge) or more at 20 [deg]C (680 [deg]F),
or which are liquefied or liquefied and refrigerated. The change is
intended to clarify that the pressure of the receptacle is measured at
standard conditions. OSHA is also proposing to add a note to Table
B.5.1 to clarify that aerosols should not be classified as gases under
pressure. This proposed change is a consequence of OSHA's proposal to
add a new hazard category for non-flammable aerosols, as discussed
previously.
Flammable Liquids--(Appendix B.6)
    OSHA is proposing to make three clarifying changes to the flammable
liquid hazard class in appendix B.6. First, OSHA is proposing to add a
reference to the Flammable Liquids standard, specifically 29 CFR
1910.106(a)(14), in paragraph B.6.3 in order to provide additional
guidance about methods that can be used to determine flashpoint.
    Second, after updating the HCS in 2012, OSHA realized there may be
a concern with ensuring that information needed to determine the
appropriate storage for flammable liquids is adequately documented on
the SDS. Per 29 CFR 1910.106(a)(5), when an accurate boiling point is
unavailable, or for mixtures which do not have a constant boiling
point, the boiling point may be based on the 10% point of a
distillation performed in accordance with the Standard Method of Test
for Distillation of Petroleum Products, ASTM D-86-62. Together with an
appropriately measured flash point, this boiling point can be used to
categorize the mixture for use with Table H-12 in Sec.  1910.106 to
determine the maximum allowable container size and type. Use of a
boiling point reported in section 9 of an SDS (physical properties),
which is based on the ``first drop'' (or initial) distillation
temperature in D-86, will likely be conservative, but may lead to more
restrictive storage requirements than would be the case using the 10%
distillation point (see appendix D, section 9(f)). OSHA is proposing to
add a clarifying footnote to B.6.3 explaining that to determine the
appropriate container size and container type for a flammable liquid,
the boiling point must be determined by the methods specified under
OSHA's Flammable Liquids standard (29 CFR 1910.106(a)(5)) and listed on
the SDS. In addition, the proposed note would explain that the chemical
manufacturer, importer, or distributor must clearly note on the SDS (in
sections 7 and 9) if a calculation other than initial boiling point was
used for storage purposes. OSHA did not intend for the updated HCS
classification requirements for flammable liquids to impact the
longstanding storage requirements under 29 CFR 1910.106 and views this
proposed note as a method to ensure that the proper container size and
type will be used for storing flammable liquids and that all necessary
information is appropriately communicated on the SDS. OSHA is not
proposing any changes to the classification criteria for flammable
liquids under the HCS. OSHA is requesting comments on whether a
footnote like the one proposed for B.6.3 should also be inserted in
appendix D, section 9.
    Finally, OSHA realized that a note regarding cross-classification
of aerosols was inadvertently omitted from appendix B.6 (flammable
liquids). In appendix B.3 (flammable aerosols), note 2 to the
classification criteria currently indicates that ``[f]lammable aerosols
do not fall additionally within the scope of flammable gases, flammable
liquids, or flammable solids.'' The HCS currently contains a cross-
referencing note in appendix B.2 (flammable gases), but OSHA
inadvertently omitted the statement in appendix B.6 (flammable
liquids). OSHA is therefore proposing to add a note stating that
aerosols should not be classified as flammable liquids in appendix B.6,
following Table B.6.1, for consistency and to minimize confusion. This
would align with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060).
Flammable Solids--(Appendix B.7)
    The only change proposed to appendix B. 7 (flammable solids) is a
new note (Note 2) following Table B.7.1 stating that aerosols should
not be classified as flammable solids. As with flammable liquids, the
UNSCEGHS observed this omission in the flammable solids chapter, and
the GHS Rev. 7 includes this note (UN GHS, 2017, Document ID 0060).
Self-Heating Chemicals--(Appendix B.11)
    OSHA proposes adding a note to Table B.11.1. This proposed note
would explain that classification of solid chemicals shall be based on
tests performed on the chemical as presented. For example, if the
chemical is presented for supply or transport in a physical form
different from that which was tested and which is considered likely to
materially alter its performance in a classification test,
classification must be based on testing of the chemical in the new
form. Although this note was included in the GHS Rev. 3 (UN GHS, 2009,
Document ID 0085), and incorporated into appendices B.1, B.7, B.10,
B.12 and B.14 in the HCS in 2012, it was inadvertently omitted from
appendix B.11. OSHA is proposing to add the note to be consistent with
the GHS and the way the HCS treats other physical hazards.
Chemicals Which, in Contact With Water, Emit Flammable Gases--(Appendix
B.12)
    OSHA proposes to update the classification criteria for Category 3
of this hazard class in Table B.12.1. In the GHS Rev. 3 (UN GHS, 2009,
Document ID 0085) and the existing HCS, one of the criteria for a
Category 3 classification is that the maximum rate of evolution of the
flammable gas is ``equal to or greater than 1 liter per kilogram of
chemical per hour.'' However, this criteria does not accurately reflect
the corresponding criteria in Test N.5 (test method for substances
which, in contact with water, emit flammable gases) in Part III, sub-
section <IP_ADDRESS>.4.4 of the UN Manual of Tests and Criteria (UN TDG,
2016, Document ID 0151), which provides that the maximum rate of
evolution of the flammable gas is greater than 1 liter per kilogram of
chemical per hour. OSHA proposes to delete the words ``equal to or'' in
the Category 3 criteria in Table B.12.1 to make the classification
criteria consistent with the criteria in the test method. This will
align the HCS with the GHS Rev.7 (UN GHS, 2017, Document ID 0060) and
would not affect worker protections.
Oxidizing Solids--(Appendix B.14)
    OSHA is proposing to add a second set of classification criteria to
B.14.2 and to Table B.14.1.based on a new UN test method. Under the GHS
Rev. 3 (UN GHS, 2009, Document, ID 0085), classification of oxidizing
solids was based only on Test O.1 from Part III, sub-section 34.4.1 of
the UN Manual of Tests and Criteria (UN TDG, 2016, Document ID 0151).
This is reflected in the current HCS, appendix B.14. However, the test
material used as the reference mixture in Test O.1 has been noted to
pose a cancer hazard and is difficult to purchase. Therefore, a new
test, Test O.3, Gravimetric tests for

oxidizing solids, has been added to Part III, sub-section 34.4.3 of the
UN Manual of Tests and Criteria (UN TDG MTC, 2016, Document ID 0151).
This new test underwent a thorough evaluation, including round robin
testing, led by the UNSCETDG (UN SCETDG, 2016, Document ID 0150). Test
O.3 uses a reference mixture of calcium peroxide and cellulose, whereas
Test O.1 uses the reference substances potassium bromate and cellulose
(UN TDG, 2016, Document ID 0165).
    Consistent with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060),
OSHA proposes to allow oxidizing solids to be classified using either
Test O.1 or Test O.3. Since the proposed classification criteria would
allow the use of data from either Test O.1 or O.3, data from existing
classifications could be used and no new testing would be required for
substances or mixtures that were previously classified based on Test
O.1.
    OSHA also proposes to update Note 1 to Table B.14.1 to reflect a
2017 revision to the International Maritime Solid Bulk Cargoes Code for
testing of explosion hazards (IMSBC, 2017, Document ID 0141).
Corrosive to Metals--(Appendix B.16)
    OSHA is not proposing to make any changes to appendix B.16,
Corrosive to Metals. This is notable because OSHA has preliminarily
decided not to adopt a note that was added in the GHS Rev. 7. Table
2.16.2 in Chapter 2.16 of the GHS Rev. 7 (UN GHS, 2017, Document ID
0060) contains a note stating: ``Where a substance or mixture is
classified as corrosive to metals but not corrosive to skin and/or
eyes, some competent authorities may allow the labelling provisions
described in <IP_ADDRESS>.5.'' Chapter <IP_ADDRESS>.5 contains labeling
provisions that apply to ``substances or mixtures which are in the
finished state as packaged for consumer use.'' OSHA has preliminarily
concluded that the note in question, and the labeling provisions it
refers to, are not applicable to the HCS because the HCS applies only
to use of chemicals in the workplace, and not to consumer products (see
29 CFR 1910.1200(b)(5)(v)). Therefore, OSHA is not proposing to adopt
the note found in Table 2.16.2 of Chapter 2.16 of the GHS Rev. 7.
Desensitized Explosives--(Appendix B.17)
    OSHA is proposing to follow the GHS Rev. 7 (UN GHS, 2017, Document
ID 0060) by adding a new physical hazard class for desensitized
explosives. Desensitized explosives are chemicals that are treated in
such a way to stabilize the chemical or reduce or suppress its
explosive properties. These types of chemicals can pose a hazard in the
workplace when the stabilizer is removed, either as part of the normal
work process or during storage of the chemical. Therefore, it is
important that the hazards be identified and appropriately
communicated.
    In the HCS, as revised in 2012, OSHA acknowledged, consistent with
the GHS Rev. 3 (UN GHS, 2009, Document ID 0085), that these chemicals
are considered explosives if the wetting agent is removed, by including
the precautionary statement ``keep wetted with'' and instructing the
chemical manufacturer, importer, or distributor to specify appropriate
material for wetting if drying out increases the explosion hazard (see
existing appendix C at C.4.14). However, the hazard statement, signal
word, pictogram and other precautionary statements required under
existing C.4.14 are geared to more conventional explosives. This gap in
communication was recognized as early as 2005, when the UNSCEGHS noted
that desensitized explosives may become explosive under certain
circumstances--especially after long term storage and during handling
and use (UN GHS, 2005, Document ID 0206). The UNSCEGHS examined the
issue of hazard classification for desensitized explosives and
concluded a new hazard class was warranted to ensure the appropriate
hazard statement, signal word and precautionary statements for
desensitized explosives were incorporated into the GHS (UN GHS, Report,
2014, Document ID 0087). The GHS Rev. 7 (UN GHS, 2017, Document ID
0060; UN GHS, 2016, Document ID 0142) separately classified
desensitized explosives with a full set of unique label elements
(including the appropriate signal word, hazard statement, pictogram,
and precautionary statements). As separately classified, desensitized
explosives are labeled with a flame pictogram rather than the explosive
bomb used for explosives, and the precautionary statements are tailored
to the specific traits of desensitized explosives (e.g., Avoid heating
under confinement or reduction of the desensitizing agent.).
    OSHA reviewed the UNSCEGHS reports (UN GHS, 2014, Document ID 0087)
on desensitized explosives and has preliminarily concluded that the
hazard class should also be added to the HCS to improve communication
about these hazards. While the chemicals captured by the desensitized
explosives hazard class are currently covered under the scope of the
HCS as explosives, OSHA believes there is a benefit to providing
classification criteria and corresponding hazard communication specific
to this hazard. Adding the proposed new hazard class to the HCS would
ensure downstream users receive more accurate hazard information on
labels and in SDSs for these chemicals.
    For these reasons, and to align with the GHS, OSHA proposes to add
the desensitized explosives hazard class to the HCS as appendix B.17.
Proposed appendix B.17 provides relevant definitions and general
considerations, specifies applicable classification criteria, and
includes information about additional classification considerations for
this hazard class. It also references several sections from the UN
Recommendations on the Transport of Dangerous Goods, Manual of Tests
and Criteria that will be incorporated by reference. As with all hazard
classes, the GHS Rev. 7 (UN GHS, 2017, Document ID 0060) does not
require testing and allows classifiers to use data reported in the
literature (UN TDG, 2016, Document ID 0151) that was generated using
specified (or equivalent) test methods. Proposed appendix C.4.30,
discussed later in this document, contains proposed communication
elements for desensitized explosives.
    Proposed appendix B.17 is based on Chapter 2.17 of the GHS Rev. 7
(UN GHS, 2017, Document ID 0060). OSHA is proposing to adopt most of
the classification language on desensitized explosives from Chapter
2.17 of the GHS Rev. 7 (UN GHS, 2017, Document ID 0060) to minimize
deviations from the GHS. However, OSHA has carefully reviewed each of
the hazard classification criteria within the context of the HCS and is
proposing to modify some of the language. These edits include changing
some recommendations in the GHS to mandatory requirements in the HCS
(i.e., changing ``should'' to ``shall''); revising some terms in the
GHS to more accurately reflect terminology in the HCS (e.g., changing
``manufacturer/supplier'' to ``manufacturers, importers, and
distributors''); revising text to make it clear that data for
classification can be obtained from the literature; and removing
references to classifications for transportation that do not apply
under the HCS. Some of the GHS text stressing where a classification
scheme is for scenarios other than transportation would also be removed
(e.g., terms referring to storage, supply, and use); this change is
being proposed because the HCS does not cover transportation, and it is
therefore not necessary to include such language in appendix B of the
HCS. OSHA also proposes adding a definition for ``phlegmatized'' in a

footnote because many stakeholders may be unfamiliar with that term
from the UN Recommendations (UN GHS, 2017, Document ID 0060).
    OSHA is not proposing to include portions of the GHS Chapter 2.17
that do not relate specifically to the method of classification for
desensitized explosives; this is the same approach OSHA took in the
2012 update. For example, similar to how OSHA has addressed the other
hazard classes, OSHA is not proposing to adopt the decision logics from
the GHS in appendix B.17; OSHA may, however, use them in guidance
materials. Also, OSHA did not include text relating to hazard
communication in proposed appendix B.17 because this information is
contained in proposed appendix C.

E. Appendix C

    OSHA is proposing a number of updates to appendix C of the HCS in
an effort to improve communication of hazard information on labels.
These proposed changes will: (1) Address labeling requirements for the
new hazard classes and categories in appendix B (physical hazards); (2)
align the HCS with the GHS Rev. 7; and (3) improve alignment of the HCS
and Health Canada's labeling requirements in furtherance of the goals
of the RCC.
    Appendix C is the mandatory appendix that includes the requirements
and instructions for the allocation of label elements. Paragraph (f)(2)
of the HCS requires the chemical manufacturer, importer, or distributor
to ensure that the information provided on the label is in accordance
with appendix C. Appendix C provides hazard statements, signal words,
pictograms, and precautionary statements for all four essential aspects
of hazardous chemical management (prevention, response, storage and
disposal), as well as general labeling instructions.
    As discussed in the 2009 NPRM proposing to align the HCS with the
GHS, the precautionary statements, unlike the hazard statements, were
not harmonized (but were merely codified) under the GHS, meaning that
numbers were assigned to them. This meant that the statements were not
yet considered to be part of the harmonized text (like hazard
statements); rather they were included in the GHS as suggested language
(74 FR 50282-83). OSHA chose to add these statements in the final HCS
rule in 2012 (77 FR 17574). However, since the promulgation of the
updates to the HCS in 2012, the UNSCEGHS has continued work to improve
the utility of precautionary statements by providing better guidance on
the allocation of statements, updating the statements to provide better
protection, and adding new statements for new hazard classes and
categories. OSHA is proposing a number of changes based on new
precautionary statements and instructions in the GHS Rev. 7.
Additionally, since 2012, OSHA has continued to work with other Federal
agencies on crosscutting labeling issues. The updates proposed in
appendix C would ensure alignment with DOT labeling regulations and are
expected to provide the same level of protection for workers as the
current HCS. OSHA is also proposing updates to appendix C based on the
agency's cooperation with Health Canada under the RCC. The RCC was
reaffirmed through a memorandum of understanding that was signed in
June 2018 (RCC, 2019, Document ID 0217), with the expectation of
aligning efforts for international trade requirements between the two
countries.
    Overall, OSHA expects that the proposed changes to appendix C would
provide improved safety information and greater detail and clarity for
downstream users. They also would provide better consistency that
bridges the jurisdictional differences between countries and Federal
agencies. Aligning the HCS with the GHS and other Federal or
international regulations would ease compliance burdens for U.S.
stakeholders that must also comply with those requirements. The changes
that OSHA is proposing would lead to improved communication of hazard
information, which would maintain or enhance the safety and health of
workers.
    The changes OSHA is proposing to appendix Care extensive. OSHA
addresses the substantive proposed changes in the discussion below, and
a redline strike out version of appendix C, which reflects all of
OSHA's proposed revisions, is available in the docket and on the OSHA
website (OSHA HCS Redline Document, 2020, Document ID 0222; https://www.osha.gov/dsg/hazcom/). This will allow interested parties to view
all of the proposed changes in context. OSHA strongly encourages
stakeholders to review that document in conjunction with the discussion
of the proposed revisions below, as the discussion below does not fully
describe all of the non-substantive or editorial changes OSHA is
proposing.
Proposed Changes to C.1-C.3
    The instructions currently found in the beginning of appendix C
(see C.1-C.3) provide directions and information about the signal
words, pictograms, hazard statements and precautionary statements
required per C.4. OSHA is proposing changes to C.1-C.3 to align with
the GHS Rev. 7, better harmonize the HCS with DOT regulations, and
better harmonize the HCS with Health Canada.
    First, OSHA proposes to revise Figure C.1--Hazard Symbols and
Classes to include ``HNOC (non-mandatory)'' as a hazard identified by
the exclamation point pictogram. This proposed change reflects OSHA's
agreement with Health Canada to permit the exclamation mark pictogram
to be used for HNOCs. While OSHA does not require labelling for HNOC
hazards, Health Canada requires a pictogram, signal word, hazard
statements, and precautionary statements for HNOCs. In order to ensure
that U.S. and Canadian requirements can simultaneously be met for
HNOCs, OSHA and Health Canada have provided guidance allowing an
exclamation mark pictogram to be used for HNOCs (OSHA, 2016, Document
ID 0103). Use of the exclamation mark pictogram would not be mandatory
under the HCS.
    Relatedly, OSHA is proposing a number of additional changes. As
discussed above, OSHA is proposing to move the current C.2.3.3 from
appendix C to paragraph (f)(5) in the text of the standard, so that all
of the instructions related to the transport of hazardous chemicals and
DOT are in one section of the HCS. OSHA is also proposing to add a new
paragraph C.2.3.3, which would allow the exclamation mark pictogram to
be used for HNOCs if the words ``Hazard Not Otherwise Classified'' or
the letters ``HNOC'' appear below the pictogram on the label. Health
Canada and OSHA have agreed that the exclamation mark pictogram is an
appropriate symbol for the HNOC, HHNOC (Health Hazards Not Otherwise
Classified), and PHNOC (Physical Hazards Not Otherwise Classified)
classifications. Additionally, because any pictogram may appear only
once on a label, OSHA is also proposing to add a new paragraph at
C.2.3.4 to specify that if multiple hazards require use of the same
pictogram, it may not appear a second time on the label. This includes
when the exclamation mark pictogram would be used, including as
supplemental information for another hazard, such as HNOC. OSHA is
requesting comments on these proposed changes, and is particularly
interested in comments on whether the agency should require the
exclamation mark pictogram to be used for HNOCs.
    The remaining changes proposed for C.2 reflect updates to the GHS
that are intended to provide additional flexibility to the label
preparer while still communicating the required

information. OSHA is proposing to add new paragraph C.2.4.7 to note
that precautionary statements may contain minor textual variations from
the text prescribed elsewhere in appendix C (e.g., spelling variations,
synonyms or other equivalent terms), as long as those variations assist
in the communication of safety information without diluting or
compromising the safety advice. This proposed new paragraph would also
provide that any variations must be used consistently throughout the
label and SDS. Because of the proposed addition of new paragraph
C.2.4.7, OSHA is also proposing to renumber existing paragraphs C.2.4.7
and C.2.4.8 to become C.2.4.8 and C.2.4.9, respectively.
    OSHA is also proposing to add a new paragraph, C.2.4.10, to further
address cases where substances or mixtures may trigger multiple
precautionary statements for medical responses. Consistent with the GHS
Rev. 7 (UN GHS, 2017, Documents ID 0060), OSHA is proposing principles
for addressing situations where a substance or mixture is classified
for a number of hazards and triggers multiple precautionary statements
for medical responses (e.g., calling a poison center/doctor/. . . . and
getting medical advice/attention). Proposed paragraph C.2.4.10 would
provide for a system of prioritization for precautionary statements.
Under proposed C.2.4.10(a), labels would usually need only include one
precautionary statement reflecting the response at the highest level
with the greatest urgency, combined with at least one route of exposure
or symptom ``IF'' statement. For example, the statement, ``Immediately
call a poison center/doctor/. . .'' would be prioritized over the less
urgent ``call a poison center/doctor.''
    OSHA believes there is value in including more than one
precautionary statement related to medical response to address both
immediate (acute) and long-term (chronic) medical concerns; appropriate
medical care may be different depending on whether there is a medical
emergency (e.g., chemical burns) or concerns about potential diseases
(e.g., cancer) due to prolonged exposures. However, OSHA also
understands the difficulty involved in providing a long list of medical
responses and that this could lead to confusion, particularly when
immediate action is required. Therefore, proposed paragraph C.2.4.10(b)
would allow for (but not require) combination of medical response
statements. This means that if a chemical has, for example, inhalation
and skin contact hazards that would require the same level of medical
response, both of these routes of entry could be listed in a combined
statement. Proposed paragraph C.2.4.10(c) would prohibit the
combination of medical response statements where the statements ``Get
medical advice/attention if you feel unwell'' and ``Get immediate
medical/advice attention'' are both indicated. In those cases, both
statements should appear without prioritization. OSHA is requesting
comments on whether precautionary statements for medical responses
should be prioritized and seeks input on the best method(s) to use for
prioritization.
Proposed Revisions to C.4
    OSHA is proposing to update the hazard label elements for specific
hazard classes and categories. The following discussion on proposed
revisions to C.4 is organized according to: (1) Labeling changes
resulting from the addition of hazard classes and categories in
appendix B (new subcategories for flammable gases (C.4.15), Aerosols
category 3 (C.4.16), and desensitized explosives (C.4.30)); (2)
revisions to hazard statements, hazard categories and notes; (3)
revisions to precautionary statements; and (4) the GHS revisions that
OSHA is not proposing to adopt. In the discussion of precautionary
statements, OSHA will explain the proposed changes to the statements
and indicate what hazard classes/categories trigger these statements.
As noted previously, a redline strike out version of appendix C is
available in the docket and on OSHA's website so interested parties can
see all of the proposed changes in context (OSHA HCS Redline, 2020,
Document ID 0222; https://www.osha.gov/dsg/hazcom/).
Proposed Revisions Based on Additions of Hazard Classes and Categories
    OSHA is proposing a number of consequential revisions to appendix C
based on the proposed additions of hazard classes and categories to
appendix B. As discussed in the Summary and Explanation for appendix B,
OSHA is proposing a number of changes to the flammable gas hazard
class. The changes would include: (1) Subdividing category 1 flammable
gases into categories 1A and 1B; (2) adding pyrophoric gases into
category 1A; and (3) adding chemically unstable gases into category 1A
(further subdivided into chemically unstable gas A and chemically
unstable gas B). The proposed hazard and precautionary statements for
those gases, consistent with the GHS Rev. 7 (UN GHS, 2017, Document ID
0060) are in C.4.15. Each type of category 1A gas (including pyrophoric
gases and chemically unstable gases) would require the hazard statement
``Extremely flammable gas,'' as is currently required for category 1
gases. On the other hand, the hazard statement for the new category 1B
flammable gases would be ``Flammable gas.'' Additional hazard and
precautionary statements would be added to communicate hazards specific
to, and precautions that need to be taken for, pyrophoric and
chemically unstable gases.
    As also discussed in the Summary and Explanation for appendix B,
OSHA is proposing to add non-flammable aerosols to the existing
``Flammable Aerosols'' hazard class and to rename the class
``Aerosols.'' Consequently, in appendix C, OSHA proposes to adopt the
GHS Rev. 7 (UN GHS, 2017, Document ID 0060) hazard and precautionary
statements for non-flammable aerosols in C.4.16. OSHA believes that
these communication requirements would better address the true hazards
of aerosols. In cases where aerosols are currently labeled as gases
under pressure, the proposal would require the label to be updated to
include the flame pictogram for hazard categories 1 and 2 (no pictogram
would be required for hazard category 3) and the signal word
``warning'' (if ``danger'' is not required due to flammability); the
hazard statement ``pressurized container, may burst if heated'' would
also be required. These changes would better differentiate the hazards
of non-flammable aerosols from those of gases under pressure.
    Finally, OSHA is also proposing to adopt the hazard class of
desensitized explosives in appendix B, and consequently to adopt, in
appendix C, the pictogram, signal word, hazard statements, and
precautionary statements for desensitized explosives from the GHS Rev.
7 (UN GHS, 2017, Document ID 0060). Under the proposal, the labeling
information for desensitized explosives would be at C.4.30.
    For flammable gases, aerosols, and desensitized explosives, OSHA is
proposing to adopt the GHS Rev. 7 (UN GHS, 2017, Document ID 0060)
hazard communication information with only minor editorial revisions,
such as the use of HCS instead of GHS terminology (e.g.,
``manufacturer, importer or distributor'' instead of ``manufacturer/
supplier or the competent authority'' in conditional instructions).
OSHA believes that the information called for by the GHS Rev. 7 (UN
GHS, 2017, Document ID 0060) effectively communicates the hazards of
those substances and the precautions that need to be taken when
handling them.

Therefore, requiring the information to appear on labels would improve
hazard communication and enhance worker safety. In addition, because
the changes would align the HCS with the GHS, adopting them would ease
compliance burdens for U.S. stakeholders that must also comply with
international requirements for hazard communication.
Proposed Revisions to Hazard and Precautionary Statements, Hazard
Categories, and Notes
    OSHA is proposing to revise a number of hazard and precautionary
statements to align with the GHS Rev. 7. The hazard and precautionary
statements in the current HCS were adopted from the GHS Rev. 3. Since
the HCS was last updated in 2012, the UNSCEGHS has continued to discuss
the utility and readability of the label elements, including hazard and
precautionary statements, in order to improve the information
presented. The specific goals of the UNSCEGHS are to make labeling
information more comprehensible and useable by explaining and
clarifying ambiguous or unhelpful instructions or statements and
eliminating inconsistencies in statements (UN GHS, 2018, Document ID
0095; UN GHS, 2018, Document ID 0213). In addition, the UNSCEGHS is
considering how precautionary statements could be consolidated or
combined to save label space and make labels more readable and clear,
all of which improve the safety message (UN GHS, 2018, Document ID
0095; UN GHS, 2018, Document ID 0213). OSHA shares these goals with the
UNSCEGHS because they lead to better communication of hazards and
therefore maintain or enhance protection of worker safety and health.
Unless otherwise discussed below, OSHA is proposing to adopt the
updated communication information presented in the GHS Rev. 7 (UN GHS,
2017, Document ID 0060) with only minor editorial revisions, such as
using the HCS terminology instead of the GHS terminology (e.g.,
``manufacturer, importer or distributor'' instead of ``manufacturer/
supplier or the competent authority'' in conditional instructions).
Proposed Revisions to Tables C.4.1, C.4.2, and C.4.3 (Acute Toxicity
Tables)
    OSHA is proposing to consolidate hazard category information for
acute toxicity--oral, C.4.1. The change would involve deleting the
table for acute toxicity--oral, category 3 and combining categories 1,
2, and 3 in one table, since all three categories have the same
precautionary statements. None of the substantive communication
information for categories 1, 2, or 3 would change, and the intent of
the proposed modification is simply to make C.4.1 more concise.
Proposed Revisions to Precautionary Statements
    The original GHS (UN GHS Rev. 1, 2005, Document ID 0215)
precautionary statements were developed from existing classification
systems, including the IPCS International Chemical Safety Card (ICSC)
Compilers Guide (IPCS International, 2012, Document ID 0158), the
American National Standards (ANSI Z129.1 2010, Document ID 0102), the
EU classification and labelling directives, the Emergency Response
Guidebook (UN TDG, 2016, Document ID 0218), and the Pesticide Label
Review Manual of the United States Environmental Protection Agency
(EPA, 2018, Document ID 0056). Since publication of the updates to the
HCS in 2012, the UNSCEGHS has continued its ongoing review of the
precautionary statements to ensure they are allocated to the correct
hazard class and/or category, reduce redundancies, simplify and clarify
the statements, and clarify and refine the conditions of use. This
section discusses OSHA's proposed revisions to precautionary statements
in appendix C.4. The intent or reasons provided below for the proposed
changes reflect OSHA's preliminary agreement with explanations provided
by the UNSCEGHS, unless otherwise specified. The changes are organized
according to the column headings found in the C.4 tables (i.e.,
prevention, response, storage, and disposal).
Proposed Changes in Prevention Column
    Wear protective equipment (e.g., gloves/protective clothing).
    A precautionary statement for acute toxicity--dermal (categories 1-
4) (Table C.4.2), skin corrosion/irritation (categories 1A-1C) (Table
C.4.4), eye damage/irritation (categories 1 and 2A) (Table C.4.5), and
sensitization--skin (Table C.4.7) specifies personal protective
equipment, such as ``wear protective gloves'' or ``wear eye protection/
face protection.'' Instructions for the statement currently indicate
that the chemical manufacturer, importer, or distributer is ``to
specify type of equipment.'' OSHA proposes to revise the instruction to
state that the chemical manufacturer, importer, or distributor may
further specify type of equipment where appropriate. The intent of this
proposed revision is to clarify that label preparers may provide
additional specification about the type of protective equipment, where
appropriate, and to align with the GHS Rev. 7 (UN GHS, 2017, Document
ID 0060).
    Because specific hazards may require specific protective equipment
or instructions, current precautionary statements and instructions for
certain health hazards (e.g., germ cell mutagenicity, see Table C.4.8;
carcinogenicity, see Table C.4.9; and reproductive toxicity, see Table
C.4.10) and the majority of physical hazard classes specify one or more
types of personal protective equipment and indicate that the chemical
manufacturer, importer, or distributor is to specify the type of
equipment. The types of equipment currently listed in the HCS were
adopted from the GHS Rev. 3 and vary for the different hazard classes.
In 2010, the UNSCEGHS recommended that the precautionary statement
``Wear protective gloves/protective clothing/eye protection/face
protection'' be used for the hazard classes of germ cell mutagenicity
(C.4.8), carcinogenicity (C.4.9), reproductive toxicity (C.4.10),
explosives (C.4.14) and unstable explosives (C.4.30) (UN GHS, 2010,
Document ID 0149), and this statement was included in the HCS in 2012.
In 2015, the UNSCEGHS noted that hearing protection should often be
worn when handling explosives and other physical hazards, such as
desensitized explosives, because an explosion would result in a
potentially hazardous noise level (UN GHS, 2015, Document ID 0219).
Accordingly, the UNSCEGHS revised the precautionary statement to read,
``Wear protective gloves/protective clothing/eye protection/face
protection/hearing protection. . .'' (UN GHS, 2016, Document ID 0147).
Adding the term ``/hearing protection. . .'' provides flexibility
because hearing protection and other equipment can be selected when
appropriate and not selected if not relevant. Adding the ellipsis at
the end of the statement allows other types of personal protective
equipment to be listed as necessary. The UNSCEGHS also revised the
instruction for the precautionary statement to make it clear that it is
referring to personal protective equipment. Consistent with the GHS
Rev. 7 (UN GHS, 2017, Document ID 0060) OSHA is proposing to adopt this
revised precautionary statement and instruction for all relevant
hazards: germ cell mutagenicity (C.4.8), categories 1A, 1B, and 2;
carcinogenicity (C.4.9), categories 1A, 1B, and 2; reproductive
toxicity (C.4.10), categories 1A, 1B, and 2; explosives (C.4.14),

unstable and division 1.1-1.5; flammable gases (C.4.15), category 1A,
pyrophoric; flammable liquids (C.4.19), categories 1, 2, 3, and 4;
flammable solids (C.4.20), categories 1 and 2; self-reactive substances
and mixtures (C.4.21), categories Types A, B, C, D, E, and F;
pyrophoric liquids (C.4.22), category 1; pyrophoric solids (C.4.23),
category 1; self-heating substances and mixtures (C.4.24), categories
1, and 2; substances and mixtures which, in contact with water, emit
flammable gases (C.4.25), categories 1, 2, and 3; oxidizing liquids
(C.4.26), categories 1, 2, and 3; oxidizing solids (C.4.27), categories
1, 2, and 3; organic peroxides (C.4.28), categories Types A, B, C, D,
E, and F; and desensitized explosives (proposed new C.4.30), categories
1, 2, 3, and 4.
Avoid Contact During Pregnancy/While Nursing
    In Table C.4.10, for reproductive toxicity (effects on or via
lactation), OSHA is proposing to revise a precautionary statement that
currently says to avoid contact ``during pregnancy/while nursing'' so
it reads ``during pregnancy and while nursing.'' This proposed revision
would clarify that the chemical manufacturer, importer or distributor
is not to choose between ``during pregnancy'' and ``while nursing'' but
is to include both scenarios on the label. This proposed change would
align with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS,
2012, Document ID 0155).
Do Not Handle Until all Safety Precautions Have Been Read and
Understood
    For unstable explosives (Table C.4.14), OSHA is proposing to delete
the precautionary statement about not handling until all safety
precautions have been read and understood. A statement to obtain
special instructions before use is already included and that statement
is shorter and more relevant to safety. This proposed change would
align with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS,
2012, Document ID 0155).
Do Not Subject to Grinding/Shock/Friction
    OSHA also proposes adding the precautionary statement ``Do not
subject to grinding/shock/friction/. . .'' to the table for unstable
explosives (Table C.4.14). That statement is already included for the
other explosives categories, and is also relevant for unstable
explosives. For each of the explosives categories that contain that
statement, an explanatory conditional note clarifying that the
statement applies only if the explosive is mechanically sensitive would
also be added. These proposed changes would align with the GHS Rev. 7
(UN GHS, 2017, Document ID 0060; UN GHS, 2012, Document ID 0152; UN GHS
2012, Document ID 0153).
Keep Away From Heat/Sparks/Open Flames/Hot Surfaces
    A number of the hazard classes that include flammable chemicals
currently require precautionary statements and instructions about
keeping away from ignition sources (heat/sparks/open flames/hot
surfaces). Those statements generally require the chemical
manufacturer, importer, or distributor to select one or more of the
ignition sources listed, as applicable. OSHA is proposing to include
more ignition sources in the statement and to require that they all be
listed on the label. With that change, the statement would read, ``Keep
away from heat, hot surfaces, sparks, open flames, and other ignition
sources.'' OSHA believes this change, which is consistent with the GHS
Rev.7 (UN GHS, 2017, Document ID 0060; UN GHS, 2012, Document ID 0152),
would improve hazard communication by making users aware of additional
ignition sources that should be avoided. The change would be made to
precautionary statements for explosives (divisions 1.1-1.5 in Table
C.4.14), flammable gases (Table C.4.15), aerosols (Table C.4.16),
flammable liquids (Table C.4.19), flammable solids (Table C.4.20),
self-reactive substances and mixtures (Table C.4.21), pyrophoric
liquids (Table C.4.22), pyrophoric solids (Table C.4.23), oxidizing
liquids (Table C.4.26), oxidizing solids (Table C.4.27), organic
peroxides (Table C.4.28), and desensitized explosives (Table C.4.30).
Keep Wetted With
    A conditional instruction used for division 1.1-1.3 and 1.5
explosives in Table C.4.14 currently states that the chemical
manufacturer, importer, or distributer is to include the precautionary
statement ``Keep wetted with. . .'' under conditions where drying would
increase the explosion hazard, except as needed for manufacturing or
operating processes. The GHS Rev. 7 changes the conditional instruction
to clarify that the ``Keep wetted with. . .'' statement should be used
for ``substances or mixtures which are wetted, diluted, dissolved or
suspended with a phlegmatizer to reduce or suppress their explosive
properties'' (UN GHS, 2017, Document ID 0060; UN GHS, 2012, Document ID
0152; UN GHS, 2012, Document ID 0153). OSHA is proposing to make the
same change in order to clarify when the ``Keep wetted with. . .''
statement is appropriate.
    The ``Keep wetted with. . .'' precautionary statement also appears
in proposed C.4.30, desensitized explosives. Consistent with the GHS
Rev. 7 (UN GHS, 2017, Document ID 0060), OSHA is not proposing to add
the conditional statement that appears in C.4.14 because, by
definition, desensitized explosives are phlegmatized to suppress their
explosive properties, and therefore the ``Keep wetted with. . .''
statement is appropriate for all desensitized explosives. OSHA requests
comment on these proposed changes.
Keep Only in Original Container
    OSHA proposes to revise the statement ``Keep only in original
container'' to ``Keep only in original packaging'' for self-reactive
substances and mixtures (Table C.4.21), organic peroxides (Table
C.4.28), and corrosive to metals (Table C.4.29). The revised statement
would also be added to explosives in division 1.1-1.5 (Table C.4.14).
OSHA believes that this proposed change is appropriate because the term
``packaging'' is more inclusive than ``container'' and would include
the transport packaging as well as the immediate container. These
proposed changes are consistent with the GHS Rev. 7 (UN GHS, 2017,
Document ID 0060; UN GHS, 2012, Document ID 0152).
Ground/Bond Container and Receiving Equipment
    Several hazard classes require the precautionary statement
``Ground/bond container and receiving equipment'' for chemicals that
are electrostatically sensitive. OSHA proposes changing ``Ground/bond''
to ``Ground and bond'' to clarify that both of those precautions are to
be included on the label. Appendix C.2.4.2, states that when a ``/'' is
used the label preparer has a choice and should choose the most
appropriate phrase. However, in this case, both ``ground and bond''
should be stated together to appropriately protect against
electrostatically sensitive chemicals. These proposed changes would
apply to explosives (division 1.1-1.5 in Table C.4.14), flammable
liquids (categories 1-3 in Table C.4.19), and flammable solids (Table
C.4.20). In addition, OSHA is proposing to revise existing conditional
instructions to clarify that the need for grounding and bonding applies
to flammable liquids only if they are volatile and may generate an
explosive atmosphere (Table C.4.19) and to

explosives and flammable solids only if they are electrostatically
sensitive (Tables C.4.14 and C.4.20). OSHA is also proposing to add the
``ground and bond'' precautionary statement and similar conditional
notes (``if electrostatically sensitive and able to generate an
explosive atmosphere'') to self-reactive substances and mixtures (Table
C.4.21) and organic peroxides (Table C.4.28) because the precaution is
also appropriate for those hazard classes. These proposed changes would
align with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS,
2012, Document ID 0152).
Keep/Store Away From Clothing, and Other Combustible Materials
    OSHA is proposing to standardize precautionary statements regarding
combustible materials for oxidizing chemicals. Currently, the tables
for oxidizing gases (Table C.4.17), oxidizing liquids (Table C.4.26,
hazard categories 2 and 3), and oxidizing solids (Table C.4.27, hazard
categories 2 and 3) require the precautionary statement ``Keep/Store
away from clothing/. . . /combustible materials,'' along with
instructions for the chemical manufacturer, importer, or distributor to
specify incompatible materials. OSHA proposes to change the statement
to read: ``Keep away from clothing and other combustible materials,''
and to delete the instruction regarding incompatible materials, to make
the statement more consistent with the statement currently applicable
to hazard category 1 in both oxidizing liquids (Table C.4.26) and
oxidizing solids (Table C.4.27). OSHA believes the proposed change is
appropriate because the general term ``combustible materials''
encompasses any other materials that are incompatible with oxidizers.
In addition, OSHA believes the term ``keep'' is adequate to encompass
storage as well as use, and that eliminating the choice between
``keep'' and ``store'' would avoid confusion and improve consistency.
Finally, OSHA is also proposing to remove the redundant statement
``Take any precaution to avoid mixing with combustibles/. . .'' under
oxidizing liquids (Table C.4.26) and oxidizing solids (Table C.4.27),
since this information is duplicative of the ``keep away from''
statement. These proposed changes are consistent with the GHS Rev. 7
(UN GHS, 2017, Document ID 0060; UN GHS, 2012, Document ID 0152).
    OSHA is proposing to remove the ``keep/store away from clothing/. .
. /combustible materials'' precautionary statement, along with its
instruction, for self-reactive substances and mixtures (Table C.4.21)
and organic peroxides (Table C.4.28). The wording of the precautionary
statement is pertinent to oxidizing properties, which readily give
oxygen or other oxidizing material, and therefore more readily support
combustion. Neither self-reacting chemicals nor organic peroxides have
oxidizing properties, so the statement is not appropriate for them.
Both self-reacting chemicals and organic peroxides have alternate
storage statements that are designed to more accurately address their
particular chemical properties. These proposed changes would also align
with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS, 2012,
Document ID 0152; UN GHS, 2012, Document ID 0153).
Keep Valves and Fittings Free From Oil and Grease
    For oxidizing gases (Table C.4.17), a precautionary statement
currently allows the chemical manufacturer, importer, or distributor to
specify that either ``reduction valves'' or ``valves and fittings'' be
kept free from oil and grease. OSHA is proposing to revise the
statement to ``Keep valves and fittings free from oil and grease.''
OSHA believes the change is appropriate because all valves and fittings
must be kept free of oil and grease, not just the reduction valves
attached to pressure receptacles. This proposed change is consistent
with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS, 2010,
Document ID 0149).
Wear Cold Insulating Gloves/Face Shield/Eye Protection
    OSHA is proposing to revise the precautionary statement for
refrigerated liquefied gases (Table C.4.18), which currently provides
that either cold insulated gloves, a face shield, or eye protection is
to be used. The proposed change would clarify the intent of the
precautionary statement, which is that cold-insulating gloves are to be
used in addition to either a face shield or eye protection. This
proposed change would align with the GHS Rev. 7 (UN GHS, 2017, Document
ID 0060; UN GHS, 2012, Document ID 0152; UN GHS, 2012, Document ID
0153).
Keep Container Tightly Closed
    The precautionary statement ``Keep container tightly closed'' is
used for flammable liquids (categories 1-3 in Table C.4.19). The GHS
Rev. 7 contains a conditional instruction indicating that the statement
is to be used if the liquid is volatile and may generate an explosive
atmosphere (UN GHS, 2017, Document ID 0060). OSHA is proposing to add
this conditional instruction to the precautionary statement for
flammable liquids (categories 1-3) because it clarifies the types of
flammable liquids for which the statement applies.
    OSHA also proposes to add the precautionary statement ``Keep
container tightly closed'' to pyrophoric liquids (Table C.4.22) and
pyrophoric solids (Table C.4.23). OSHA believes it is important to add
that statement because for both pyrophoric liquids and pyrophoric
solids it is necessary to avoid ignition via contact with air. Because
the precaution applies to all chemicals in these hazard classes, OSHA
does not believe a conditional note is necessary. These proposed
changes would also align with the GHS, Rev. 7 (UN GHS, 2017, Document
ID 0060; UN GHS, 2012, Document ID 0152; UN GHS, 2012, Document ID
0153).
Take Precautionary Measures Against Static Discharge
    For flammable liquids (Table C.4.19, hazard categories 1-3), OSHA
proposes to revise the precautionary statement ``Take precautionary
measures against static discharge'' to ``Take action to prevent static
discharge.'' The revision would simply shorten the statement and
clarify what action needs to be taken. OSHA also proposes to add a note
that this precautionary statement is to be used if the liquid is
volatile and may generate an explosive atmosphere. These proposed
changes are consistent with the GHS Rev. 7 (UN GHS, 2017, Document ID
0060; UN GHS, 2012, Document ID 0152; UN GHS, 2012, Document ID 0153).
Flammable Liquids/Solids Conditional Instructions
    OSHA is proposing additional conditional instructions for flammable
liquids (Table C.4.19) and flammable solids (Table C.4.20). Some
categories of flammable liquids (categories 1-3) and flammable solids
(categories 1 and 2) contain a precautionary statement specifying the
use of ``explosion-proof [electrical/ventilating/lighting/. . .]
equipment.'' OSHA believes that SDS and label creators are not actually
properly and specifically identifying the prevention measures for the
particular chemical, but rather are listing the entire line without the
required details. For liquids, OSHA proposes a new conditional
instruction to clarify that the statement is required if the chemical
is volatile and may generate an explosive atmosphere. For both liquids
and solids, a conditional instruction would be added to indicate that
text in

square brackets may be used to specify specific electrical,
ventilating, lighting or other equipment if necessary and as
appropriate. These proposed changes would align with the GHS Rev. 7 (UN
GHS, 2017, Document ID 0060; UN GHS, 2012, Document ID 0152; UN GHS,
2012, Document ID 0153).
    OSHA is also proposing to add a conditional instruction to the
precautionary statement to use non-sparking tools for flammable liquids
(categories 1-3, Table C.4.19). The statement would clarify that the
precautionary statement is only needed if the liquid is volatile and
may generate an explosive atmosphere, and if the minimum ignition
energy is very low (<0.1 mJ). The precautionary statement has very
limited applicability for flammable liquids and therefore OSHA believes
that the conditions need to be specified. This proposed change is also
consistent with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS,
2012, Document ID 0152; UN GHS, 2012, Document ID 0153).
Keep Cool
    For self-reactive substances and mixtures and organic peroxides
(Tables C.4.21 and C.4.28), OSHA is proposing to move the precautionary
statement ``Keep cool'' from the storage column to the prevention
column. The precautionary statement is not needed in the storage column
because that column includes a precautionary statement about storage
temperatures not to be exceeded, and as discussed below, OSHA is
proposing to add conditional instructions to that column to inform
users of when a storage temperature would need to be listed. Under the
prevention column, OSHA is proposing to include a conditional
instruction indicating that the precautionary statement may be omitted
if storage temperatures are included on the label. This proposed
revision would not materially change the information that is presented
on the label, and is consistent with the GHS Rev. 7 (UN GHS, 2017,
Document ID 0060; UN GHS, 2012, Document ID 0152; UN GHS, 2012,
Document ID 0153).
    For self-heating substances and mixtures (Table C.4.24), a combined
precautionary statement currently instructs the user to keep cool and
protect from sunlight. OSHA is proposing that a conditional instruction
be added to indicate that ``Keep cool'' can be omitted where storage
temperatures are listed on the label. Because ``Protect from sunlight''
still needs to be included if specific storage temperatures are listed
on the label, OSHA is proposing to delete the combined statement under
the prevention column, and to list only ``Keep cool'' (and the new
conditional instruction) in that column. The statement: ``Protect from
sunlight'' would be moved to the storage column, similar to the way
this is handled for other hazard classes. OSHA believes that these
proposed changes would provide the label preparer better instructions
and would provide the appropriate level of information on the label
without repetition. These proposed changes would also align with the
GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS, 2012, Document ID
0152; UN GHS, 2012, Document ID 0153).
Do Not Allow Contact With
    OSHA is proposing to add the conditional note ``if emphasis of the
hazard statement is deemed necessary'' to precautionary statements
indicating that contact is not to be allowed with air (for pyrophoric
gases (proposed C.4.15, category 1A), pyrophoric liquids (C.4.22), and
pyrophoric solids (C.4.23)) or water (for substances and mixtures that
emit flammable gases in contact with water (C.4.25, categories 1 and
2). Because the hazard phrases, which are also included on labels for
these categories, already warn about the hazards of these respective
chemicals when they contact air or water, adding this precautionary
statement as well could be repetitive. However, depending on the
specific chemical, the label preparer may feel that added emphasis is
warranted. These proposed changes would align with the GHS Rev. 7 (UN
GHS, 2017, Document ID 0060; UN GHS, 2012, Document ID 0152; UN GHS,
2012, Document ID 0153).
Handle Contents Under Inert Gas
    For substances and mixtures which, in contact with water, emit
flammable gases (Table C.4.25), OSHA proposes changing the
precautionary statement ``Handle under inert gas. Protect from
moisture'' to ``Handle and store contents under inert gas/. . . Protect
from moisture.'' This would clarify that these substances should always
be under inert atmospheres. In addition, conditional instructions would
be added to indicate that if the substance or mixture reacts readily
with moisture in air, then the chemical manufacturer, importer or
distributer also has to specify the appropriate liquid or gas if inert
gas is not appropriate. The new statement would provide greater clarity
and is needed because inert gas is not appropriate in some cases (e.g.,
white phosphorus should be handled and stored under water) (UN GHS,
2010, Document ID 0149). This proposed change is consistent with the
GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS, 2012, Document ID
0152; UN GHS, 2012, Document ID 0153).
    OSHA is also proposing to add the statement ``Handle and store
contents under inert gas/. . .'' to pyrophoric liquids (C.4.22) and
pyrophoric solids (C.4.23). A conditional statement would note that the
manufacturer, importer, or distributor is to specify the appropriate
liquid or gas if inert gas is not appropriate. Pyrophoric chemicals, by
definition, are likely to ignite when in contact with air. Both Tables
C.4.22 and C.4.23 currently contain the following statement in the
storage column: ``Store contents under . . . Chemical manufacturer,
importer, or distributor to specify appropriate liquid or inert gas.''
In light of the language OSHA is proposing to include in the prevention
column, OSHA would delete this language from the storage column. OSHA
believes that the language being proposed for the prevention column
would emphasize that pyrophoric chemicals must be handled, as well as
stored, under inert atmospheres. OSHA notes that the statements OSHA is
proposing to add to the prevention column for Tables C.4.22 (pyrophoric
liquids) and C.4.23 (pyrophoric solids) regarding handling and storing
contents under inert gas were included in the GHS Rev. 5, but were
inadvertently omitted from Rev. 7 (UN GHS, 2016, Document ID 0211; UN
GHS, 2017, Document ID 0060). If OSHA finalizes the language as
proposed, it will work with the UNSCEGHS to have this statement
reinstated in future GHS revisions.
Wear Fire/Flame Resistant/Retardant Clothing
    Category 1 oxidizing liquids (C.4.26) and category 1 oxidizing
solids (C.4.27) currently have the precautionary statement ``Wear fire/
flame resistant/retardant clothing.'' The intent of that statement is
to alert the users of the chemical that they should wear either fire
resistant or flame retardant clothing, not for the label preparer to
choose between the terms ``fire'' and ``flame'' or ``resistant'' and
``retardant''. Therefore, OSHA proposes to replace the existing
statement with ``Wear fire resistant or flame retardant clothing.''
This would clarify the intent of this statement and is consistent with
the GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS, 2012, Document
ID 0152; UN GHS, 2012, Document ID 0153).

Proposed Changes in Response Column
    For the response column, a number of the proposed revisions in
appendix C are simply editorial and are made to improve clarity,
correct simple omissions of a word or phrase, or more efficiently and
concisely combine different precautionary statements. For example, OSHA
is proposing to add the phrase ``If on skin'' to the statement ``Brush
off loose particles from skin'' (see C.4.23 (pyrophoric solids) and
hazard categories 1 and 2 in C.4.25 (substances and mixtures which, in
contact with water, emit flammable gasses)) because those statements
are always combined in the GHS Rev. 7 (UN GHS, 2017, Document ID 0060),
and the additional phrase would add clarity. Another example is OSHA's
proposal to add the phrase ``In case of fire'' at the beginning of the
precautionary statements related to fire fighting for unstable
explosives, as is already done for other explosives categories (see
C.4.14). In a number of cases, OSHA is proposing to reorganize the
precautionary statements and to remove redundant wording to improve
clarity. For example, in C.4.14, instead of listing the individual
statements and providing conditions of use, OSHA would now list the
statements grouped together (except for materials for Division 1.4S,
which have another set of statements as explained below).
    The following discussion does not address proposed changes that are
simply editorial in nature (although all proposed revisions can be
found in the redlined version of appendix C that is available as part
of the rulemaking record (OSHA HCS Redline, 2020, Document ID 0222) and
on OSHA's website (https://www.osha.gov/dsg/hazcom). The discussion
below highlights the substantive changes OSHA is proposing to make to
the response column in appendix C.
Take Off Immediately All Contaminated Clothing. Rinse Skin With Water/
Shower
    The existing precautionary statements for skin corrosion/irritation
(categories 1A to 1C in C.4.4) and flammable liquids (categories 1-3 in
C.4.19) indicate that if the chemical is on hair or skin, the affected
individual is to immediately take off all contaminated clothing and
rinse skin with ``water/shower.'' OSHA proposes to revise the statement
to instruct the affected individual to rinse skin with ``water [or
shower],'' and to add a conditional note indicating that the text in
square brackets is to be used where the chemical manufacturer, importer
or distributor considers it appropriate for the specific chemical. The
reason for the proposed change is that a deluge shower might be most
appropriate for the chemical, and the use of the square brackets allows
for selection of the most appropriate wording. The proposed change
would align with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN
GHS, 2012, Document ID 0152; UN GHS, 2012, Document ID 0153).
Get Medical Advice/Attention
    A number of health hazards (i.e., skin corrosion/irritation
(category 2 in Table C.4.4), eye damage/irritation (categories 2A and
2B in Table C.4.5), sensitization--skin (Table C.4.7), germ cell
mutagenicity (Table C.4.8), carcinogenicity (Table C.4.9), reproductive
toxicity (Table C.4.10), specific target organ toxicity--repeated
exposure (Table C.4.12), and refrigerated liquefied gases (Table
C.4.18)) have combined precautionary statements that include the
statement ``get medical advice/attention.'' OSHA is proposing to add an
instruction indicating that the chemical manufacturer, importer, or
distributer is to select medical advice or attention as appropriate.
This is to alert label preparers that they should provide more specific
instruction on the type of medical assistance needed based on the
chemical hazard and to align with the GHS Rev. 7 (UN GHS, 2017,
Document ID 0060).
If Breathing Is Difficult, Remove Person to Fresh Air and Keep
Comfortable for Breathing
    A precautionary statement used for sensitization--respiratory
(Table C.4.6) currently states ``If inhaled: If breathing is difficult,
remove person to fresh air and keep comfortable for breathing.'' OSHA
is proposing to remove the phrase ``if breathing is difficult.'' This
is because including two conditions, ``if inhaled'' and ``if breathing
is difficult,'' is confusing and unnecessary. Removal of the phrase
would also make the precautionary statement consistent with the
statement as it appears in other hazard classes in appendix C.4, such
as acute toxicity--inhalation (Table C.4.3). This proposed change is
consistent with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS,
2010, Document ID 0149).
Take Off Contaminated Clothing and Wash it Before Reuse
    A precautionary statement for skin sensitization (Table C.4.7)
currently says to wash contaminated clothing before reuse. OSHA is
proposing to add the phrase ``Take off contaminated clothing and'' to
this precautionary statement. The UNSCEGHS previously recommended that
this additional phrase be used for acute toxicity--dermal; skin
irritation, category 2; and sensitization--skin (UN GHS, 2010, Document
ID 0154). The phrase was inadvertently omitted for skin sensitization
in the GHS Rev. 3 (UN GHS, 2009, Document ID 0085), and accordingly in
the updates to the HCS in 2012, but it has since been added to the GHS
Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS, 2010, Document ID 0149;
UN GHS, 2010, Document ID 0154).
If Exposed or Concerned
    For specific target organ toxicity (single exposure) (Table
C.4.11), OSHA is proposing to revise a precautionary statement
indicating ``If exposed'' to ``If exposed or concerned.'' The revision,
which would be consistent with language currently used for the germ
cell mutagenicity (Table C.4.8), carcinogenicity (Table C.4.9), and
reproductive toxicity (Table C.4.10) hazard classes, would maintain
consistency throughout C.4 and with the GHS Rev. 7 (UN GHS, 2017,
Document ID 0060). In 2010, a GHS subcommittee recommended that
wherever ``If exposed'' is used, it be revised to ``If exposed or
concerned,'' since the user of the chemical may not have evidence of
exposure (UN GHS, 2010, Document ID 0154).
Division 1.4 Explosives (C.4.14) Precautionary Statements
    For Division 1.4 explosives, the HCS currently provides fire-
fighting precautionary statements and instructions on when to apply
them (Table C.4.14). OSHA is proposing two changes to these statements.
First, OSHA is proposing to change the instruction note from ``for
explosives are 1.4S ammunition and components thereof'' to ``for
explosives of division 1.4 (compatibility group S) in transport
packaging.'' This revision would provide clarity about when the note
applies and there is no intended change in meaning. Second, OSHA is
proposing to revise the precautionary statement ``Fight fire with
normal precautions from a reasonable distance'' to the statement
``Fight fire remotely due to the risk of explosion.'' OSHA believes the
proposed new statement is more appropriate and protective because it
specifies the explosion risk due to fire associated with 1.4
compatibility group S (1.4S) explosives. These proposed changes would
align with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS,
2012, Document ID 0152; UN GHS, 2012, Document ID 0153).

Eliminate All Ignition Sources, if Safe To Do So
    For category 1 and 2 flammable gases (C.4.15), a precautionary
statement currently instructs the user to eliminate all ignition
sources if safe to do so. OSHA proposes to revise the statement to ``In
case of leakage, eliminate all ignition sources.'' The term ``in case
of leakage'' would be added to stress that it is important to eliminate
flammable gas leaks, even where the leaking gas is not burning, because
the leak could create an explosive atmosphere. The term ``if safe to do
so'' would be deleted because it could discourage quick action.
Eliminating gas leaks would not be expected where a fire would hinder
that action. OSHA is also proposing to add this statement to pyrophoric
gases 1A and chemically unstable gases A and B. These proposed changes
would be consistent with the GHS Rev. 7 (UN GHS, 2017, Document ID
0060; UNGHS, 2012, Document ID 0152).
In Case of Fire Use . . . To Extinguish
    For self-reactive substances and mixtures (type A) (C.4.21), OSHA
is proposing to delete the precautionary statements ``In case of fire
use . . . to extinguish'' (along with its explanatory note) and ``Fight
fire remotely due to the risk of explosion.'' In place of the language
OSHA is proposing to delete, OSHA proposes to use language stating ``In
case of fire: Explosion risk. Do NOT fight fire when fire reaches
explosives.'' These changes would align with the GHS Rev. 7 (UN GHS,
2017, Document ID 0060) and are proposed because it is dangerous to
fight a fire involving this type of material and individuals should
always be advised against it (UN GHS, 2012, Document ID 0152; UN GHS,
2012, Document ID 0153). OSHA is not proposing to change the existing
statement about evacuating the area.
    For type B self-reactive substances and mixtures (C.4.21), OSHA is
proposing to combine existing precautionary statements and to delete
duplicate phrases that would occur with the new combination. OSHA does
not intend these changes to alter the meaning of the statements. OSHA
is proposing to use brackets around the statement ``Use . . . to
extinguish'' with a conditional note to indicate that the text in
square brackets is to be included if water increases risk. This is to
preserve the conditions of use with the new combination of phrases.
These proposed changes would align with the GHS Rev. 7 (UN GHS, 2017,
Document ID 0060; UN GHS, 2012, Document ID 0095).
Fire and Explosion Hazards for Organic Peroxides (C.4.28)
    Precautionary statements and instructions related to fire and
explosion hazards or fire-fighting procedures were not included in the
GHS Rev. 3 (UN GHS, 2009, Document ID 0085), or in the current HCS, for
organic peroxides (C.4.28). The UNSCEGHS has since adopted these
precautionary statements (UN GHS, 2012, Document ID 0095). As in GHS
Rev. 7 (UN GHS, 2017, Document ID 0060), OSHA is proposing to adopt the
same precautionary statements in the response column for organic
peroxides (C.4.28) as for self-reactive substances and mixtures
(C.4.21). OSHA believes it is appropriate to include these statements
for organic peroxides, as well as for self-reactive substances and
mixtures, because the fire and explosion hazards of the two classes of
compounds are equivalent (UN GHS, 2012, Document ID 0152; UN GHS,
Document ID 0153; UN GHS, 2012, Document ID 0095).
Immerse in Cool Water/Wrap With Wet Bandages
    For pyrophoric liquids (C.4.22), pyrophoric solids (C.4.23), and
substances and mixtures which in contact with water emit flammable
gases (C.4.25), a precautionary statement currently indicates that if
the substance is on the skin, the user should ``immerse in cool water/
wrap with wet bandages.'' For pyrophoric liquids (C.4.22) and solids
(C.4.23), OSHA is proposing to change the forward slash to an ``or'' so
that the statement would read ``Immerse in cool water or wrap in wet
bandages.'' The change is proposed to make clear that the chemical
manufacturer, importer, or distributer is not to choose one action or
the other but is to include both actions on the label. In the case of
substances and mixtures which, in contact with water, emit flammable
gases, OSHA is proposing to delete ``wrap in wet bandages'' from the
statement so that the complete statement reads ``Brush off loose
particles from skin and immerse in cool water.'' This change is
proposed because, for these chemicals, a large volume of water is
needed and wrapping in wet bandages is not enough to address problems
caused by the heat of the reaction (UN GHS, 2012, Document ID 0095).
These proposed changes would align with the GHS Rev. 7 (UN GHS, 2017,
Document ID 0060; UN GHS, 2012, Document ID 0152; UN GHS, 2012,
Document ID 0153).
Proposed Changes in Storage Column
Store Away From Other Materials
    For self-reactive substances and mixtures (C.4.21), self-heating
substances and mixtures (C.4.24), and organic peroxides (C.4.28), OSHA
proposes to revise the precautionary statement ``Store away from other
materials'' to ``Store separately.'' OSHA believes that the revised
statement is preferable because it is shorter and more appropriate.
OSHA is also proposing to add the ``Store separately'' precautionary
statement to category 1 oxidizing liquids (C.4.26) and category 1
oxidizing solids (C.4.27) because those chemicals are not compatible
with other chemicals and thus must be stored separately. These proposed
changes are consistent with the GHS Rev. 7 (UN GHS, 2017, Document ID
0060; UN GHS, 2012, Document ID 0152; UN GHS, 2012, Document ID 0153).
Store Contents Under. . . .
    For pyrophoric liquids (C.4.22) and solids (C.4.23), OSHA proposes
to delete a precautionary statement that says ``Store contents under .
. . ,'' along with the instructional note that the chemical
manufacturer, importer, or distributer is to specify the appropriate
liquid or inert gas. The UNSCEGHS recommended that the statement be
deleted from the storage column because it adopted the statement
``Handle and store contents under inert gas/ . . . ,'' along with a
similar instructional note, in the prevention column (UN GHS, 2012,
Document ID 0152; UN GHS, 2012, Document ID 0153). OSHA believes
placing the statement in the prevention column is more appropriate, as
there it would warn the downstream user that pyrophoric chemicals must
be under inert gas not only during storage but at all times, including
during processing and use. This modification was inadvertently omitted
from the text in the GHS Rev. 7, and the U.S. will work with the U.N.
to submit a paper to add this statement to pyrophoric liquids (C.4.22)
and solids (C.4.23) in a future revision of the GHS.
Maintain Air Gap Between Stacks/Pallets
    For self-heating substances and mixtures (C.4.24), OSHA is
proposing to revise the precautionary statement that currently says
``[m]aintain air gap between stacks/pallets'' so it reads instead
``[m]aintain air gap between stacks or pallets.'' The change would
clarify that chemical manufacturers, importers or distributors are not
to choose between ``stacks'' or ``pallets''

but are to include both words on the label. This proposed change would
align with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS,
2012, Document ID 0152; UN GHS, 2012, Document ID 0153).
Store in Corrosive Resistant/ . . . Container With a Resistant Inner
Liner
    A precautionary statement for the corrosive to metals (C.4.29)
class currently says to store in a ``corrosive resistant/ . . .
container with a resistant inner liner.'' OSHA is proposing to change
the word ``corrosive'' to ``corrosion'' because it is the technically
correct term. In addition, a new conditional instruction would be
inserted to indicate that the precautionary statement may be omitted if
the statement ``Keep only in original packaging'' is included on the
label. This would eliminate the redundancy of including both
statements. These proposed changes would align with the GHS Rev. 7 (UN
GHS, 2017, Document ID 0060; UN GHS, 2012, Document ID 0152; UN GHS,
2012, Document ID 0153).
Instructional Notes
    For acute toxicity--inhalation (C.4.3) (category 1-3) and specific
organ toxicity (single exposure, category 3) (C.4.11), OSHA is
proposing minor, non-substantive edits to the conditional instruction
for precautionary statements about keeping the container tightly closed
and storing in a well-ventilated place. OSHA proposes to revise the
note from ``if product is volatile so as to generate hazardous
atmosphere'' to ``if the chemical is volatile and may generate a
hazardous atmosphere.'' The intent of these edits is to improve clarity
and make the instruction more consistent with a newly added instruction
for flammable liquids (C.4.19). This proposed change is consistent with
the GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS, 2012, Document
ID 0152; UN GHS, 2012, Document ID 0153).
    For flammable liquids (C.4.19), OSHA is proposing to add a
clarifying instruction indicating that the precautionary statement
``Store in a well ventilated place. Keep cool'' applies to flammable
liquids in category 1 and other flammable liquids that are volatile and
may generate an explosive atmosphere. However, for category 4 flammable
liquids, OSHA is proposing to delete ``Keep cool,'' because these
liquids are less volatile and have a flashpoint above 60 [deg]C and
therefore are unlikely to generate a hazardous concentration of vapor
during storage; OSHA believes the precautionary statement ``Store in a
well ventilated place'' is the appropriate level of protection. These
proposed changes would align with the GHS Rev. 7 (UN GHS, 2017,
Document ID 0060; UN GHS, 2012, Document ID 0152; UN GHS, 2012,
Document ID 0153).
    For explosives (C.4.14), OSHA is proposing minor edits to
precautionary statements and instructions for storing in accordance
with local/regional/national/international regulations. The edits are
intended to clarify that the chemical manufacturer, importer, or
distributer is to specify the applicable regulations. These proposed
changes are consistent with the GHS Rev. 7 (UN GHS, 2017, Document ID
0060; UN GHS, 2012, Document ID 0152; UN GHS, 2012, Document ID 0153).
    Aerosols (C.4.16), self-reactive substances (C.4.21), self-heating
substances and mixtures (C.4.24), and organic peroxides (C.4.28)
currently include precautionary statements addressing storage
temperatures not to be exceeded, with temperatures listed in degrees
Celsius/Fahrenheit. The GHS has added an instruction that the chemical
manufacturer should use the applicable temperature scale for the region
they are supplying (UN GHS, 2017, Document ID 0060; UN GHS, 2012,
Document ID 0152; UN GHS, 2012, Document ID 0153). In other OSHA
standards, the primary temperature scale used is Fahrenheit. Therefore,
OSHA is proposing to require only the Fahrenheit scale in the
precautionary statements. However, the chemical manufacturer, importer
or distributor would still be permitted to include the temperature in
Celsius (as noted by parens ( )) in addition to Fahrenheit.
    In addition, for self-reactive substances and mixtures (C.4.21) and
organic peroxides (C.4.28), OSHA proposes to add conditional
instructions to two precautionary statements. The first conditional
instruction would clarify that the statement to store in a well-
ventilated place should not be used for temperature-controlled
substances and mixtures or organic peroxides because condensation and
freezing may occur. The second would clarify that a storage temperature
is only needed if temperature control is required or deemed necessary.
OSHA also proposes moving the precautionary statement ``Keep cool'' to
the prevention column, as discussed above under the section on proposed
changes to the prevention column. These proposed changes would align
with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS, 2012,
Document ID 0152; UN GHS, 2012, Document ID 0153).
Proposed Changes in Disposal Column
    For most of the health and physical hazards addressed by appendix
C, the rule currently includes a precautionary statement to dispose of
contents/container in accordance with local/regional/national/
international regulations (to be specified). OSHA is proposing to add
an instructional note in all relevant places in the appendix indicating
that the chemical manufacturer, importer or distributor is to specify
whether the disposal requirements apply to the contents, the container,
or both. This proposed change would align with the GHS Rev. 7 (UN GHS,
2017, Document ID 0060; UN GHS, 2012, Document ID 0152; UN GHS, 2012,
Document ID 0153).
    The tables for explosives (C.4.14), except for hazard category
division 1.6, currently include the precautionary statement to dispose
of contents/container in accordance with local/regional/national/
international regulations (to be specified). However, this
precautionary statement may not give users the information needed to
safely dispose of explosives, particularly malfunctioning, expired, or
non-used explosives where special care is needed. This is of particular
concern for explosives such as fireworks, signal flares and ammunition.
Ill-formulated advice on the label may lead to the disposal of such
explosive waste in a way that poses a risk, e.g., to the workers that
handle the waste (UN GHS, 2015, Document ID 0156). Therefore, OSHA is
proposing to change the precautionary note for explosives (C.4.14) to
read: ``Refer to manufacturer, importer, or distributor . . . for
information on disposal, recovery, or recycling.'' An instructional
note would be added to indicate that the chemical manufacturer,
importer, or distributor is to specify the appropriate source of
information, in accordance with local/regional/national/international
regulations as applicable. The change is proposed to address the
recycling or recovery of unexploded fireworks or other unused explosive
cartridges and signal flares, which can result in unsafe conditions and
should only be performed by specialists. This proposed change is
consistent with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS,
2015, Document ID 0214; UN GHS, 2015, Document ID 0213).
Proposed Revisions to Label Elements for OSHA Defined Hazards (C.4.31)
    OSHA is proposing a few changes to label elements for OSHA defined
hazards (currently at C.4.30 and proposed to be renumbered as C.4.31).

This section of appendix C addresses the labeling of hazards that are
not classified under the GHS, but that the HCS specifically defines as
hazards that must be communicated on the label and SDS.
    First, OSHA is proposing to delete the entry for ``Pyrophoric
Gas.'' In the GHS Rev. 7, pyrophoric gases are now a category under the
hazard class of flammable gases, and OSHA proposes to include them
there as well.
    OSHA is also proposing a change to the ``Combustible Dust'' hazard
statement. When OSHA finalized the revisions to the HCS in 2012, the
GHS did not address classification of combustible dust; however, it
used combustible dust as an example of ``Other hazards which do not
result in classification'' (UN GHS, 2009, Document ID 0085). In the GHS
Rev. 5, the UN updated A.<IP_ADDRESS> to include a statement ``May form
explosible dust-air mixture if dispersed'' for dust explosion hazards
to provide guidance on the type of statement that should be used in the
case of dust explosion hazards (combustible dust) (UN GHS, 2012,
Document ID 0251). Subsequently, OSHA initiated UNSCEGHS discussions
regarding combustible dust hazards. The UNSCEGHS adopted an annex
(Annex 11) that provides additional guidance on hazard identification,
the factors that contribute to a dust explosion hazard, and the need
for risk assessment, prevention, mitigation, and communication (UN GHS,
2017, Document ID 0157). OSHA is now proposing to allow either the
previously required statement, ``may form combustible dust
concentrations in air,'' or the statement suggested in the GHS Annex 4,
``[m]ay form explosible dust-air mixture.'' OSHA is proposing to add
square brackets after both statements containing the following
language: ``if small particles are generated during further processing,
handling or by other means.'' This bracketed language is designed to
indicate that this language should be added when the material can
create a combustible dust hazard during the processing or handling of
the chemical. OSHA is not proposing any changes to the signal word of
``warning'' or any pictogram requirements. These changes are the result
of working papers presented to the UNSCEGHS meetings for discussion in
December of 2017 (UN GHS, 2017, Document ID 0157).
GHS Revisions That OSHA Is Not Proposing To Adopt
    There are a small number of revisions in the GHS Rev. 7 that OSHA
is not proposing to adopt for the HCS. In general, OSHA does not
propose to adopt any statements or conditional instructions that
address consumer products because the HCS does not cover communication
of hazards to consumers. This section discusses specific provisions in
the GHS Rev. 7 (UN GHS, 2017, Document ID 0060) that OSHA is not
proposing to adopt.
    A number of tables for inhalation hazards in appendix C.4 (i.e.,
acute toxicity--inhalation (C.4.3, categories 3 and 4), respiratory
sensitization (C.4.6), skin sensitization (C.4.7), and specific target
organ toxicity--single exposure (C.4.11, category 3)) contain a
precautionary statement that says ``Avoid breathing dust/fume/gas/mist/
vapors/spray.'' A conditional note in the GHS Rev. 7 (UN GHS, 2017,
Document ID 0060) indicates that this precautionary statement is not
needed where the precautionary statement ``Do not breathe dust/mist/
fume/gas/vapors/spray'' is included on the label. Also, for skin
corrosion/irritation (C.4.4, category 2), the GHS Rev. 7 (UN GHS, 2017,
Document ID 0060) contains a conditional note indicating that the
statement ``If skin irritation occurs: Get medical advice/attention''
may be omitted if the statement ``If skin irritation or rash occurs:
Get medical advice or treatment'' is used. OSHA is not proposing to
adopt these conditional instructions because it believes that proposed
appendix C.2.4.8 (currently C.2.4.7), which provides instructions for
the precedence of precautionary statements, already provides the
necessary flexibility.
    In the GHS Rev. 7, the precautionary statements about explosion-
proof equipment and taking action to prevent static discharge include a
conditional instruction indicating that these precautionary statements
can be omitted if national or local legislation contains provisions
that are more specific (UN GHS, 2017, Document ID 0060). OSHA is not
proposing to adopt this instruction because the agency believes these
precautionary statements contain important information that should
always be included on labels. Although some OSHA and consensus
standards address the use of explosion-proof equipment and preventing
static discharge for flammable liquids or solids, they do not address
hazard communication. Therefore, OSHA does not believe they are
specific enough to justify omitting the relevant precautionary
statement from labels. Label preparers can add more specific
supplementary information from standards as long as it complies with
paragraph C.3. For example, they may reference OSHA's flammable liquids
standard (29 CFR 1910.106), which addresses the requirements for
electrical equipment in workplaces that store or handle flammable
liquids. OSHA requests comments on its preliminary decision not to
include the conditional instruction from the GHS.
    Under the HCS, a precautionary statement for gases under pressure
(C.4.18) currently says ``Protect from sunlight.'' The GHS Rev. 7
contains a conditional instruction indicating that this precautionary
statement ``may be omitted for gases filled in transportable gas
cylinders in accordance with packing instruction P200 of the UN
Recommendations on the Transport of Dangerous Goods, Model Regulations,
unless those gases are subject to (slow) decomposition or
polymerization, or the competent authority provides otherwise'' (UN
GHS, 2017, Document ID 0060). These special packaging instructions
under P200 are not applicable to cylinders used in the U.S; therefore,
OSHA is not proposing to add this conditional instruction to C.4.18 (UN
GHS, 2017, Document ID 0060).

F. Appendix D

    OSHA is proposing several changes to appendix D. These changes are
being proposed to align with the GHS Rev. 7 (UN GHS, 2017, Document ID
0060) to clarify existing requirements where stakeholders have
expressed confusion, and to ensure consistency with updated scientific
principles. A redline strike out version of appendix D, which reflects
all of OSHA's proposed revisions, is available in the docket and on the
OSHA website (OSHA HCS Redline 2020, Document ID 0222); https://www.osha.gov/dsg/hazcom/). This will allow interested parties to view
all of the proposed changes in context. OSHA strongly encourages
stakeholders to review that document in conjunction with the discussion
of the proposed revisions below.
    In the introductory section of appendix D, OSHA proposes to add a
sentence stating that while each section of the SDS must contain all of
the specified information, preparers of SDSs are not required to
present the information in any particular order within each section.
OSHA proposes this change to help clarify that while all required
information must be present on the SDS, there are no mandates about the
order in which the information is presented within each section.
Because the information within each section can be listed in any order,
OSHA does not anticipate any increased burden on SDS preparers from
this change.
    In section 1, Identification, OSHA is proposing revisions to
clarify that the address and telephone number provided

on the SDS must be domestic. Although OSHA explained in a 2016 letter
of interpretation that a U.S. telephone number and U.S. address are
required for the SDS and label (Lee, 2016, Document ID 0090), OSHA
believes it is important to codify this requirement in the text of the
HCS to minimize any future confusion.
    In section 2, Hazard(s) identification, OSHA is proposing to
clarify where and how chemical hazard information should be presented.
First, OSHA proposes to clarify that paragrah (a) must include any
hazards associated with a change in the chemical's physical form under
normal conditions of use, an issue the agency has addressed in several
LOIs (Cawthorn, 2014, Document ID 0238; McCarthy, 2015, Document ID
0185; Fox, 2008; Document ID 0239). For example, for a chemical that
poses a combustible dust hazard when processed (but not in the form in
which it is shipped), the combustible dust hazard must be included in
section 2(a). OSHA is also proposing a new paragraph (c) covering
hazards identified under normal conditions of use that result from a
chemical reaction (changing the chemical structure of the original
substance or mixture). One example of such a reaction under normal
conditions of use is the chemical change and subsequent physical
effects of adding water to ready-mix concrete or cement, which creates
additional hazards besides those present before the water is added
(MST; 1995, Document ID 0253). This information is already required on
the SDS (Boros, 2014, Document ID 0171), but OSHA believes that adding
this language in paragraph (c) of section 2 would provide a clear and
separate location for chemical manufacturers, distributors and
importers to place this information. To accommodate the new material
being proposed for paragraph (c), OSHA is proposing to move existing
paragraphs (c) and (d) to paragraphs (d) and (e). OSHA notes that if it
adopts the proposed revisions to section 2, hazards associated with
chemicals as shipped, as well as hazards associated with a change in
the chemical's physical form under normal conditions of use, would be
presented in paragraph (a), and new hazards created by a chemical
reaction under normal conditions of use would be presented in paragraph
(c). OSHA believes this would sufficiently differentiates the different
types of hazards presented under normal conditions of use, but welcomes
stakeholder comments on this issue.
    In section 3, OSHA is proposing several changes. Under the
subheading ``For Substances (d)'' OSHA is proposing to add
``(constituents)'' to clarify the term ``additives.'' OSHA intends that
any individual part of an ``additive'' that contributes to the
classification of that material needs to be listed in section 3 of the
SDS. OSHA is also proposing to revise the information provided for
mixtures. In addition to the information required for substances,
section 3 requires the chemical name of all ingredients in a mixture
that are classified as health hazards. OSHA proposes also requiring the
CAS number or other unique identifier for these ingredients. CAS
numbers are unique numerical identifiers assigned by the American
Chemical Society (ACS) (CAS, 2020, Document ID 0173). CAS numbers are
internationally recognized as being reliable and readily validated, are
unique to only one compound, substance or chemical, and provide a
common link between various nomenclature that may be used as
descriptors for the substance or compound (UN, 2005, Document ID 0130;
CAS, 2020, Document ID 0173). CAS numbers have been generated for all
substances identified from the scientific literature from 1957 to the
present, with some substances identified as far back as the early 1900s
(CAS, 2020, Document ID 0173; UN, 2005, Document ID 0130). OSHA
believes that this information provides the downstream user with
important information, since it provides a unique descriptor of the
chemical where the chemical identity may be ambiguous.
    OSHA is proposing an additional change in section 3 to reflect the
proposed revision to paragraph (i) (Trade secrets), which would allow
for concentration ranges to be withheld as a trade secret. When the
concentration or concentration range is withheld as a trade secret, the
chemical composition range would have to be provided in accordance with
the prescribed concentration ranges in paragraphs (i)(1)(iv)(A) through
(M). As explained in the summary and explanation section for paragraph
(i), this would create an alignment with the WHMIS under Health Canada
(Canadian Gazette II, 2018, Document ID 0101).
    Section 8 of the SDS includes information on exposure controls/
personal protection. Section 8(a) currently requires the SDS to include
the OSHA permissible exposure limit (PEL), American Conference of
Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV),
and any other exposure limit used or recommended by the chemical
manufacturer, importer, or employer preparing the SDS, when available.
OSHA has received questions about whether this requirement applies to
individual ingredients and constituents in the mixture, and has
explained that it applies to any ingredient or constituent identified
in section 3 of the SDS (McVeigh, 2013, Document ID 0088). To clarify
this point, OSHA is proposing to revise section 8(a) to state that it
applies to all ingredients or constituents listed in section 3. OSHA
notes, however, that if the ingredient or constituent does not have an
OSHA PEL, ACGIH TLV or any other exposure limit used or recommend by
the SDS preparer, then the ingredient or constituent would not need to
be listed in section 8.
    In addition, OSHA is also proposing to revise section 8 to add
language indicating that SDS preparers must also include a ``range'' of
exposure limits whenever a range is used or recommended by the chemical
manufacturer, importer, or employer preparing the SDS. This revision
would acknowledge new tools, such as occupational exposure banding or
hazard banding methods described by NIOSH and the United Kingdom Health
and Safety Executive (NIOSH, 2017, Document ID 0106; HSE, 2013,
Document ID 0104). Hazard banding and occupational exposure banding
provide a concentration range (band) based on toxicity and hazard
information associated with a known chemical with similar properties;
this range can inform appropriate risk management decisions where a
specific occupational exposure limit (OEL) or permissible exposure
limit (PEL) is not available or out of date (NIOSH, 2017, Document ID
0106) This type of information has been developed and validated over
the last few decades and these types of exposure ranges can provide
hazard information on chemicals that can help reduce risk to workers,
even if limited toxicological information is available (NIOSH, 2017,
Document ID 0106). As noted by NIOSH and the U.S. EPA, more than 85,000
chemicals are in commerce, with only approximately one thousand having
been assessed for hazard and toxicity (either through an authoritative
entity or peer-reviewed process) (NIOSH, 2017, Document ID 0106; EPA,
2016, Document ID 0058).
    OSHA is proposing several updates to section 9, Physical and
chemical properties. OSHA proposes to revise section 9 to align with
the GHS Rev. 7 by listing the required physical and chemical properties
of the chemical in the same order that appears in the GHS (UN GHS,
2017, Document ID 0060). While OSHA does not require SDS

preparers to list the physical and chemical properties in any
particular order, the agency is proposing this change in order to
simplify preparation for those chemical manufacturers that may prepare
SDSs for global distribution. Other proposed changes to section 9
include: Replacing ``appearance'' with ``physical state'' and
``color''; eliminating ``odor threshold'' and ``evaporation rate'' as
separate required properties; adding the term ``kinematic'' to the
property ``viscosity'' in order to better define the appropriate
parameter to be characterized (i.e., kinematic as opposed to dynamic
viscosity); and adding ``particle characteristics'' as a new physical
property. Particle characteristics apply to solids only and the
description should include the particle size (median and range) and, if
available and appropriate, further properties such as size distribution
(range), shape and aspect ratio, and specific surface area. Particle
characteristics can be an important indicator of the potential for a
solid particle to pose a hazard as particles that are less than 100
microns increase the likelihood of exposure, especially through the
route of inhalation (UN GHS, 2017, Document ID 0060; UN GHS, 2016;
Document ID 0143, UN GHS, 2014, Document ID 0129).
    OSHA is proposing one change to section 10 of the SDS, Stability
and reactivity. Section 10(c) requires preparers to include the
possibility of hazardous reactions, and OSHA is proposing to clarify
that this includes hazardous reactions associated with foreseeable
emergencies. The proposed language is consistent with the language OSHA
is proposing for paragraph (d)(1) (Hazard classification).
    In addition, OSHA is proposing to revise section 11, Toxicological
information, to align with the GHS Rev. 7 (UN GHS, 2017, Document ID
0060) by adding interactive effects as paragraph (e). In light of that
proposed change, OSHA is proposing to move existing paragraph (e) to
paragraph (f). OSHA also proposes to add a new paragraph (g), providing
that when specific chemical data or information is not available, SDS
preparers must indicate if alternative information is used and the
method used to derive the information (e.g., where the preparer is
using information from a class of chemicals rather than the exact
chemical in question and using structure activity relationships (SAR)
to derive the toxicological information). SAR and QSAR (quantitative
SAR) are predictive tools that utilize the properties from known
chemical structures and properties in relation to their biological
activity to predict activities and properties of untested chemicals
based on their structural similarity to tested chemicals (EPA, 2016,
Document ID 0179). Read across is another predictive technique that
uses information on an endpoint from a known (tested) substance to
predict endpoint information from a similar (but unknown or untested)
substance (ECHA, 2016, Document ID 0178). Specific, detailed examples
of read across, SAR and QSAR are provided on the OECD's website for
chemical safety--assessment of chemicals (OECD, 2019, Document ID 0091;
EPA, 2016, Document ID 0179; ECHA, 2016, Document ID 0178). This
proposed change reflects the advancement in the scientific application
of computational toxicology to hazard assessment and identification and
would align with the GHS Rev. 7 (Ballabio, 2018, Document ID 0128;
Idakwo, 2020, Document ID 0123; OECD, Document ID 0091; Mangiatoridi,
2016, Document ID 0122; UN GHS, 2017, Document ID 0060).
    Finally, OSHA is proposing to change non-mandatory section 14(f),
Transport information, to read ``Transport in bulk according to IMO
instructions'' \60\ instead of ``Transport in bulk (according to Annex
II of MARPOL 73/78 and the IBC Code)'' \61\ to be consistent with text
in the GHS Rev. 7 (IMSBC, 2017, Document ID 0141). This change is an
update to the reference that previously only covered liquefied gases in
bulk. The proposed change would provide guidance that the information
in section 14 covers all bulk transport regardless of the physical form
of the cargo, in accordance with IMO instruments: e.g., Annex II or
Annex V of MARPOL 73/789, the IBC code10, the IMSBC \62\ code and the
IGC \63\ code. This change would also reflect standardization of
conventions for the technology and safety upgrades in the IMO (a global
standard-setting authority for the safety, security and environmental
performance of international shipping under the United Nations).
---------------------------------------------------------------------------

    \60\ IMO Means the International Maritime Organization.
    \61\ MARPOL means the International Convention for prevention of
Pollution from Ships.
    \62\ IMSBC Code means the International Maritime Solid Bulk
Cargoes Code, as amended.
    \63\ IGC Code means The International Code of the Construction
and Equipment of Ships Carrying Liquefied Gases in Bulk, as amended.
---------------------------------------------------------------------------

XVI. Authority and Signature

    This document was prepared under the direction of Loren Sweatt,
Principal Deputy Assistant Secretary of Labor for Occupational Safety
and Health, U.S. Department of Labor, 200 Constitution Avenue NW,
Washington, DC 20210. It is issued under the authority of sections 4,
6, and 8 of the Occupational Safety and Health Act of 1970 (29 U.S.C.
653, 655, 657); 5 U.S.C. 553; section 304, Clean Air Act Amendments of
1990 (Pub. L. 101-549, reprinted at 29 U.S.C.A. 655 Note); section 41,
Longshore and Harbor Workers' Compensation Act (33 U.S.C. 941); section
107, Contract Work Hours and Safety Standards Act (40 U.S.C. 3704);
section 1031, Housing and Community Development Act of 1992 (42 U.S.C.
4853); section 126, Superfund Amendments and Reauthorization Act of
1986, as amended (reprinted at 29 U.S.C.A. 655 Note); Secretary of
Labor's Order No. 8-2020 (85 FR 58383-94); and 29 CFR part 1911.

List of Subjects in 29 CFR Part 1910

    Chemicals, Diseases, Explosives, Flammable materials, Gases,
Hazardous substances, Incorporation by reference, Labeling,
Occupational safety and health, Safety, Signs and symbols.

    Signed at Washington, DC, on December 28, 2020.
Loren Sweatt,
Principal Deputy Assistant Secretary of Labor for Occupational Safety
and Health.

Proposed Amendments

    For the reasons set forth in the preamble, chapter XVII of title
29, part 1910 of the Code of Federal Regulations is proposed to be
amended as follows:

PART 1910--OCCUPATIONAL SAFETY AND HEALTH STANDARDS

0
1. The authority citation for part 1910 continues to read as follows:

    Authority: 33 U.S.C. 941; 29 U.S.C. 653, 655, 657; Secretary of
Labor's Order No. 12-71 (36 FR 8754); 8-76 (41 FR 25059), 9-83 (48
FR 35736), 1-90 (55 FR 9033), 6-96 (62 FR 111), 3-2000 (65 FR
50017), 5-2002 (67 FR 65008), 5-2007 (72 FR 31160), 4-2010 (75 FR
55355), 1-2012 (77 FR 3912), or 08-2020 (85 FR 58393); 29 CFR part
1911; and 5 U.S.C. 553, as applicable.

0
2. Amend Sec.  1910.6 by:
0
a. Revising the last sentence of paragraph (a)(4);
0
b. Adding paragraphs (h)(29) and (r)(2)(vi);
0
c. Redesignating paragraphs (r)(4) and (5) as paragraphs (r)(6) and
(7), redesignating paragraph (r)(3) as paragraph (r)(4), and adding new
paragraphs (r)(3) and (r)(5);
0
d. Revising paragraph (bb); and
0
e. Adding paragraphs (cc) and (dd).
    The revisions and additions read as follows:

Sec.  1910.6  Incorporation by reference.

    (a) * * *
    (4) * * * For information on the availability of this material at
NARA, email<EMAIL_ADDRESS>or go to www.archives.gov/federal-register/cfr/ibr-locations.html.
* * * * *
    (h) * * *
    (29) ASTM D 4359-90 (2019), Standard Test Method for Determining
Whether a Material is a Liquid or a Solid, Re-approved 2019, IBR
approved for Sec.  1910.1200.
* * * * *
    (r) * * *
    (2) * * *
    (vi) International Organization for Standardization, ISO Central
Secretariat, Chemin de Blandonnet 8 CP 401--1214 Vernier, Geneva,
Switzerland; Telephone: +41 22 749 01 11; Fax: +41 22 733 34 30; Email:
<EMAIL_ADDRESS>website: https://www.iso.org/store.html.
    (3) ISO 817:2014, Refrigerants--Designation and safety
classification. Third Edition, June, 2014, IBR approved for appendix B
to Sec.  1910.1200.
* * * * *
    (5) ISO 10156:2010, Gases and Gas Mixtures--Determination of Fire
Potential and Oxidizing Ability for the Selection of Cylinder Valve
Outlets, Third Edition, April, 2010, IBR approved for appendix B to
Sec.  1910.1200.
* * * * *
    (bb) Except as noted, copies of the standards listed in this
paragraph (bb) are available for purchase from United Nations
Publications, P.O. Box 960 Herndon, VA 20172; telephone: 1-703-661-
1571; fax: 1-703-996-1010; email<EMAIL_ADDRESS>    (1) European Agreement Concerning the International Carriage of
Dangerous Goods by Road (ADR), section 2.3.4 of Annex A, 2019, IBR
approved for Sec.  1910.1200. Website: https://shop.un.org/series/european-agreement-concerning-international-carriage-dangerous-goods-road-adr.
    (2) UN ST/SG/AC.10/Rev.4, The UN Recommendations on the Transport
of Dangerous Goods, Manual of Tests and Criteria, Fourth Revised
Edition, 2003, IBR approved for appendix B to Sec.  1910.1200. Copies
available from:
    (i) Bernan, 15200 NBN Way, Blue Ridge Summit, PA 17214; telephone:
1-800-865-3457; fax: 1-800-865-3450; email: [email protected];
website: http://www.bernan.com;
    (ii) Renouf Publishing Co. Ltd., 812 Proctor Avenue, Ogdensburg, NY
13669-2205; telephone: 1-888-551-7470; Fax: 1-888-551-7471; email:
<EMAIL_ADDRESS>website: http://www.renoufbooks.com; and
    (iii) United Nations Publications, Customer Service, c/o National
Book Network, 15200 NBN Way, P.O. Box 190, Blue Ridge Summit, PA 17214;
telephone: 1-888-254-4286; fax: 1-800-338-4550; email:
<EMAIL_ADDRESS>    (3) UN ST/SG/AC.10/30/Rev.6, The UN Recommendations on the
Transport of Dangerous Goods, Manual of Tests and Criteria, Sixth
Revised Edition, 2015, IBR approved for appendix B to Sec.  1910.1200.
Website: https://www.unece.org/trans/danger/publi/manual/manual_e.html.
    (cc) The following material is available for purchase from
International Electrotechnical Commission through ANSI, 25 West 43rd
Street, 4th Floor, New York, NY 10036; telephone: 1-212-642-4963; fax:
1-212-398-0023; website: https://www.iec.ch.
    (1) IEC 60079-20-1 ed. 1.0 (2010-01) Explosive atmospheres--Part
20-1: Material characteristics for gas and vapor classification--Test
methods and data, IBR approved for appendix B to Sec.  1910.1200.
    (2) [Reserved]
    (dd) The following material is available for purchase from German
Institute for Standardization (DIN) through ANSI, 25 West 43rd Street,
4th Floor, New York, NY 10036; telephone: 1-212-642-4963; fax: 1-212-
398-0023; https://din.de/en/about-standards/buy-standard.
    (1) DIN 51794--Determining the ignition temperature of petroleum
products, 2003, IBR approved for appendix B to Sec.  1910.1200.
    (2) [Reserved]
0
3. Amend Sec.  1910.1200:
0
a. By revising paragraphs (a)(1) and (b)(6)(x);
0
b. In paragraph (c):
0
i. By removing the period following the subject heading and adding a
colon in its place;
0
ii. By adding in alphabetical order definitions for ``Bulk shipment''
and ``Combustible dust'';
0
iii. By revising the definition of ``Exposure or exposed'';
0
iv. By adding in alphabetical order a definition for ``Gas'';
0
v. By revising the definition of ``Hazardous chemical'';
0
vi. By adding in alphabetical order definitions for ``Immediate outer
package'' and ``Liquid'';
0
vii. By revising the definition of ``Physical hazard'';
0
viii. By adding in alphabetical order a definition for ``Physician or
other licensed health are professional (PLHCP)'';
0
ix. By removing the definition of ``Pyrophoric gas''; and
0
x. By adding in alphabetical order definitions for ``Released for
shipment'' and ``Solid'';
0
c. By revising paragraphs (d)(1), (e)(4), and (f)(1), (5), and (11);
0
d. By adding paragraph (f)(12);
0
e. By revising paragraphs (g)(2) introductory text, (g)(10), (i)(1) and
(2), (i)(3) introductory text, and (j); and
0
f. By revising appendices A through D.
    The revisions and additions read as follows:

Sec.  1910.1200   Hazard communication.

    (a) * * *