hazards identified under normal conditions of use that result from a
chemical reaction must appear on the SDS, even though these hazards do
not need to be listed on the label. This proposed change would simply
reorganize the information presented in the SDS, as discussed in
Section XV (Summary and Explanation, Appendix D). OSHA is requesting
comments on whether the text OSHA is proposing for paragraph (c) in
section 2 would clarify when it is appropriate to include information
on the hazards associated with a change in the chemical's physical form
or chemical reaction under normal conditions of use and the type of
information that should be presented in section 2 of the SDS.
    With some conditions, the HCS currently requires section 3 of the
SDS to include the chemical name and concentration (exact percentage)
or concentration ranges of all ingredients which are classified as
``health hazards'' in accordance with paragraph (d) of Sec.  1910.1200.
OSHA is not proposing to change this requirement, but is interested in
comments on whether it should be expanded to include all classified
chemicals (i.e., also physical hazards and HNOCSs). Such a requirement
would be similar to the EU REACh regulations, which require SDS
preparers to list the classification of each hazardous ingredient
(ECHA, 2016, Document ID 0177). Would expanding the requirements for
section 3 in this way ensure that both users and manufacturers fully
understand any potential hazard when handling the chemical? Would such
a change result in the provision of additional information that would
allow downstream manufacturers to more accurately classify their
products where the mixture in question is one of their ingredients?
    The use of newer electronic technology, such as quick response (QR)
codes and radio-frequency identification (RFID), on package labels give
responsible parties the ability to communicate information on chemical
hazards in a variety of formats. In the December 2018 session of the UN
Sub-committee, the members of an informal working group on labeling of
small containers agreed to extend its scope beyond small containers
and, accordingly, to change its name to ``Practical Labelling Issues.''
Among other activities proposed for the biennium 2019-2020, the working
group planned to ``[r]eview the existing digital means of communication
that can be used to convey the GHS hazard information to users (e.g.,
electronic label, QR code etc.),'' ``consider the development of
general principles and criteria on the provision of this information
digitally,'' and ``develop guidance and examples wherever
appropriate.'' (UN GHS, 2019, Document ID 0198; UN Secretariat, 2019,
Document ID 0196).
    As an example, a paper presented at the December 2018 session of
the UN sub-committee noted that there are international efforts
``actively promoting the application of electronic labels for
chemicals'' in such industrial processes as production; management of
cylinders, laboratory samples, and warehouse operations; and the
supervision of competent persons (UN GHS, 2019, Document ID 0198). The
paper noted that common types of electronic labels include QR codes and
RFID. The paper also discussed efforts to develop national standards on
electronic labeling ``to establish a complete integrated information
managing standard system based on chemical electronic labels and safety
data'' in order to ``further ensure the effectiveness of chemical
safety supervision, promote the implementation of the Globally
Harmonized System of Classification and Labelling of Chemicals, and
facilitate . . . trade.'' Among the benefits of practical labeling
cited by the sub-committee expert are the convenience and efficiency
derived from ``unified information collection,'' ``dynamic
management,'' and ``real-time monitoring''; the ability to store a
large capacity of information, reaching multiple mega-byte levels; and
``[improvement in] the level of safety management in complex
scenarios.'' (UN GHS, 2018, Document ID 0082).
    OSHA invites comments on the use of electronic labeling for
chemical packaging. If a future revision to the HCS permitted some form
of electronic labeling, what technological, economic, and security
challenges would affected employers face? The agency also requests
comments on the types of electronic chemical labeling already in
existence or under development. For employers already implementing
electronic labeling programs in the United States or in other
countries, please provide information on the types of electronic coding
systems utilized in the program and the costs incurred and benefits
achieved from the program.

What back-up measures are in place to ensure immediate access to the
hazard information? OSHA is interested in information about workers'
experiences with the use of electronic labels. OSHA also requests
comments on foreseeable challenges that OSHA should consider (e.g.,
worker accessibility to electronic label information).
Preliminary Economic Analysis
    (1) As explained in the preliminary economic analysis (see Section
VII.F. Compliance Costs and Cost Savings), some chemical production and
logistics employees who receive training under the provisions of the
existing HCS would need to receive additional training to become
familiar with the updates to SDSs and labels for impacted aerosols,
desensitized explosives, and flammable gases. OSHA has preliminarily
determined that the incremental training costs employers would incur
for these employees will be relatively small (estimated annualized
training costs of $120,158 for all affected employers). OSHA also
believes that users of aerosols, desensitized explosives, and flammable
gases in the workplace are already trained on the hazards of these
chemicals and therefore would need to devote only a trivial amount of
time, if any time at all, to additional training associated with the
reclassification of these chemicals. Per the discussion of this issue
in the preliminary economic analysis (see ``Costs Associated with
Training Employees'' in Section VII.F. Compliance Costs and Cost
Savings), OSHA acknowledges that some user training might be required
for non-flammable aerosols not under pressure; the agency has
preliminarily concluded, however, that such training time would be
negligible given that, as discussed in Section XV.C (see Section XV,
Summary and Explanation for Appendix B), most aerosols are currently
classified as gases under pressure and therefore are already covered
under the HCS. The agency requests comments on all of its preliminary
conclusions regarding training time for users of reclassified
chemicals.
    (2) For purposes of estimating the costs associated with the
proposed new hazard classification requirements, OSHA estimates that a
Health & Safety Specialist would spend 1.75 hours per SDS for
establishments with fewer than 100 employees; 1.25 hours per SDS for
establishments with 100-499 employees; and 0.75 hours per SDS for
establishments with 500 or more employees (see ``Costs Associated with
Reclassifications and Revisions to Safety Data Sheets and Labels'' in
Section VII.F, Compliance Costs and Cost Savings). At a loaded hourly
wage of $56.87, this results in estimated unit costs of $101.51,
$72.51, and $43.50 per SDS for small, medium, and large establishments,
respectively. OSHA invites interested parties to comment on these
estimates.
    (3) For purposes of estimating the costs associated with revising
labels and SDSs to conform to the revisions OSHA is proposing to
mandatory language in the appendices, OSHA estimates that a Health &
Safety Specialist would spend 0.7 hours per SDS for establishments with
fewer than 100 employees; 0.5 hours per SDS for establishments with
100-499 employees; and 0.3 hours per SDS for establishments with 500 or
more employees (see ``Revisions to SDSs and Labels Due to Revised
Precautionary Statements,'' in Section VII.F. Compliance Costs and Cost
Savings). At a loaded hourly wage of $56.39, this results in estimated
unit costs of $40.60, $29.00, and $17.40 per SDS for small, medium, and
large establishments, respectively. OSHA invites interested parties to
comment on these estimates.
    (4) To estimate the costs (cost savings) associated with the
proposed released-for-shipment provisions in paragraph (f)(11), OSHA
presented a cost methodology that required estimating four factors: (1)
Cost savings (estimated relabeling costs) as a percentage of the value
of the products needing relabeling; (2) the percentage of products in
the affected NAICS industries that would be warehoused for more than
six months; (3) the percentage of products warehoused for more than six
months that would require relabeling in any particular year due to a
manufacturer-initiated labeling change; \58\ and (4) the percentage of
all products in the NAICS industries that would be covered by the
proposed revisions to the HCS. The estimated percentages are shown in
Table VI-17: Calculation of the Percentage Loss Avoided Due to the
Proposed Released-for-Shipment Provision. OSHA requests public comments
on its estimates for each of the four factors described above and shown
in Table VI-17.
---------------------------------------------------------------------------

    \58\ That is, a labeling change resulting from new information
obtained by the manufacturer and not from a new legal requirement.
---------------------------------------------------------------------------

    (5) As described in the PEA (see ``Released for Shipment'' in
Section VII.F. Compliance Costs and Cost Savings), OSHA anticipates
that the proposed modifications to paragraph (f)(11) addressing
chemicals that have been released for shipment would result in cost
savings for manufacturers and distributors of certain products--those
with large (and typically infrequent) production runs and lengthy shelf
lives (often five years or longer) that, during production, are
labeled, boxed, palletized, and shipped, and then go through the
distribution chain usually without the chemical contents, packaging, or
label being disturbed. OSHA identified six industries (NAICS 325311
Nitrogenous fertilizer manufacturing, NAICS 325312 Phosphatic
fertilizer manufacturing, NAICS 325314 Fertilizer (mixing only)
manufacturing, NAICS 325510 Paint and coating manufacturing, NAICS
424910 Farm supplies merchant wholesalers, and NAICS 424950 Paint,
varnish, and supplies merchant wholesalers) that it expects would be
impacted by the proposed modifications to paragraph (f)(11); see Table
VI-17 in Section VII.D. Health and Safety Benefits and Unquantified
Positive Economic Effects. OSHA invites comments on whether other
industries would be affected by this proposed modification and whether
there might be other cost or health effects resulting from this
proposed modification that OSHA did not consider in this proposal.
    (6) Also with respect to the estimate of cost savings associated
with the proposed released-for-shipment provisions, OSHA assumes that
if the relabeling costs associated with paragraph (f)(11) exceed the
value of the product, manufacturers and wholesalers will discard the
product rather than pay to relabel it. There may be some disposal costs
for the discarded material, but there may also be some salvage value to
the improperly-labeled product. In the preliminary economic analysis
(see ``Released for Shipment'' in Section VII.F. Compliance Costs and
Cost Savings), OSHA estimates, without further information on the
distribution of the costs, that the average labeling cost is
approximately 50 percent of the value of the products requiring
relabeling. The agency invites comments on this assumption.

B. Options

    In this section, OSHA presents a list of options that are under
consideration for the proposed update to the HCS. The agency is
requesting public comment on these options.
Regulatory Text
    (1) OSHA is proposing, in paragraph (i), to mandate the use of
prescriptive concentration ranges whenever an actual concentration or
concentration range is being claimed as a trade secret. This change is
being proposed, in part, to better align with Canada's Workplace

Hazardous Materials Information System (WHMIS), allowing manufacturers,
importers, and employers the ability to use the same SDS for both U.S.
and Canadian workplaces. However, the agency is also considering a non-
mandatory option for this provision. Under this scenario, OSHA would
provide non-mandatory guidance on the use of concentration ranges, but
would not require their use. This would allow manufacturers, importers,
and employers flexibility to follow the current HCS requirements (which
do not require the use of any concentration ranges when the actual
concentration is claimed as a trade secret) or move to a system that
aligns with WHMIS. OSHA is requesting comments on this option. Would
this option provide beneficial flexibility to manufacturers, importers,
and employers? Would this option be too confusing, and potentially
weaken protective effects that would be associated with providing
prescribed concentration ranges? How would this affect employee safety
and comprehension?
    (2) Under paragraph (i), OSHA is also considering allowing
manufacturers and importers to provide their own ranges as long as the
range is narrower than any prescribed range. This alternative could
allow manufacturers and importers to provide downstream users with more
precise information while still being able to claim a trade secret.
This would be consistent with an approach Health Canada is considering
(Canada, 2019, Document ID 0172). OSHA is seeking comments on the
usefulness and viability of this option.
Revision 8 Changes
    The GHS Rev. 8 was published in July 2019 and contains many changes
from Rev. 7, including updates to certain hazard classification
criteria, systematic updates to the definitions in the health hazard
chapters, updates to hazard and precautionary statements, and updated
labeling examples. An overview of the changes can be found in Document
ID 0243. As discussed more thoroughly in the introduction to the
Summary and Explanation (see Section XV), OSHA has preliminarily
decided to use this proposed update to align the HCS with the GHS Rev.
7. However, OSHA has also identified specific updates found in the GHS
Rev. 8 that are significant enough to warrant consideration in this
rulemaking. Below, the agency highlights several updates from the GHS
Rev. 8 and invites public comments on whether OSHA should consider
adopting these updates.
1. Appendix A (Based on the GHS Rev. 8)
    OSHA is proposing substantial revisions to appendix A.2 (skin
corrosion/irritation) that reflect changes the UN subcommittee adopted
through the GHS Rev. 7. However, the GHS Rev. 8, published in July 2019
(UN GHS, 2019, Document ID 0065), expanded the use of non-animal test
methods in Chapter 3.2 (skin corrosion/irritation). These changes
include recognition of specific in vitro test methods, reorganization
of the chapter, reorganization of the tiered approach with an updated
Figure 3.2.1 to reflect those changes, as well as descriptive text on
use of new test methods, structure activity relationship (SAR) and read
across methods, and an updated decision logic diagram. The expansion of
non-animal test methods for use in hazard classification could
potentially result in cost savings, as hazard testing for new chemicals
could be done using potentially cheaper (non-animal) test methods. If
OSHA were to adopt these changes, they would be reflected in appendix
A.2 Skin Corrosion/Irritation.
BILLING CODE 4510-26-P

[GRAPHIC] [TIFF OMITTED] TP16FE21.079

BILLING CODE 4510-26-C
    Table 3.2.1 from the GHS Rev. 8 (shown above) provides an update to
the tiered approach for classification. In recognition of the
advancements made in non-animal test methods, the update includes an
elevation in acceptance of in vitro data to tier 2 of the approach. The
updated tiered approach also includes consideration of conflicting
lower-tiered data when the lower tier suggests a higher classification
level. In addition to the changes in the table, Rev. 8 updates the
background information to provide additional guidance for how to use
non-animal test data to classify chemicals. Adopting these updates in
the HCS would not require a re-evaluation of chemicals already
classified because the overall tiered approach for evaluating existing
data has been retained. The agency believes the greatest benefit would
be for new chemicals where no existing data currently exists. Although
OSHA does not require testing, OSHA currently encourages chemical
manufacturers wanting to develop hazard information for new chemicals
to utilize non-animal testing strategies to develop hazard information.
Should OSHA adopt Chapter 3.2 from the GHS Rev. 8 with all of the
revisions to the classification scheme? Please explain your opinion and
provide any relevant data or other information.
2. Appendix B (Based on the GHS Rev. 8)
    In this NPRM, OSHA is proposing updates to the classification and
labeling of aerosols that will align with the GHS Rev. 7. However, the
GHS Rev. 8 contains several significant additional changes in the
aerosol chapter. OSHA requests comments on whether the agency should
adopt two specific changes that appear in the GHS Rev. 8. First, the
GHS Rev. 8 lists classification criteria for aerosols as text in a
table (see the GHS table 2.3.1, Criteria for aerosols), similar to
other hazard chapters, rather than referring classifiers to the
decision logics. When OSHA revised the HCS in 2012, the agency declined
to adopt the GHS decision logics and used its own text for
classification of flammable aerosols (Sec.  1910.1200, appendix B).
OSHA has preliminarily determined that there are no substantive
differences between OSHA's current text and the text

represented in the new Rev. 8 table (reproduced below), although they
do not contain exactly the same language (UN GHS, Rev. 8, Document ID
0065).

         Table XIV--Rev. 8 Classification Criteria for Aerosols
                    [From the GHS Rev. 8 Table 2.3.1]
------------------------------------------------------------------------
         Category                             Criteria
------------------------------------------------------------------------
1........................  (1) Any aerosol that contains >=85% flammable
                            components (by mass) and has a heat of
                            combustion of >=30 kJ/g;
                           (2) Any aerosol that dispenses a spray that,
                            in the ignition distance test, has an
                            ignition distance of >=75 cm; or
                           (3) Any aerosol that dispenses a foam that,
                            in the foam flammability test, has:
                           (a) a flame height of >=20 cm and a flame
                            duration of >=2 s; or
                           (b) a flame height of >=4 cm and a flame
                            duration of >=7 s.
2........................  (1) Any aerosol that dispenses a spray that,
                            based on the results of the ignition
                            distance test, does not meet the criteria
                            for Category 1, and which has:
                           (a) A heat of combustion of >=20 kJ/g;
                           (b) a heat of combustion of <20 kJ/g along
                            with an ignition distance of >=15 cm; or
                           (c) a heat of combustion of <20 kJ/g and an
                            ignition distance of <15 cm along with
                            either, in the enclosed space ignition test:
                              A time equivalent of <=300 s/m3; or
                              a deflagration density of <=300 g/m3; or
                           (2) Any aerosol that dispenses a foam that,
                            based on the results of the aerosol foam
                            flammability test, does not meet the
                            criteria for Category 1, and which has a
                            flame height of >=4 cm and a flame duration
                            of >=2 s.
3........................  (1) Any aerosol that contains <=1% flammable
                            components (by mass) and that has a heat of
                            combustion <20 kJ/g; or
                           (2) Any aerosol that contains >1% (by mass)
                            flammable components or which has a heat of
                            combustion of >=20 kJ/g but which, based on
                            the results of the ignition distance test,
                            the enclosed space ignition test or the
                            aerosol foam flammability test, does not
                            meet the criteria for Category 1 or Category
                            2.
------------------------------------------------------------------------

    Should OSHA adopt the classification criteria for the aerosols
hazard class as presented above? While the criteria themselves would
not change as compared to OSHA's existing standard, adopting the
precise language in the GHS text may minimize confusion.
    Second, in Rev. 8, the GHS adopted a new hazard category within the
aerosols class: Chemicals under pressure (UN GHS, 2019, Document ID
0065; UN GHS, 2018, Document ID 0247; UN GHS, 2018, Document ID 0248).
These products function similarly to aerosol dispensers (UN 1950), but
are packed in pressure receptacles (refillable and non-refillable) up
to 450 liters ((UN GHS, 2019, Document ID 0065; UN TDG, 2020, Document
ID 0195). Chemicals under pressure used for spray applications present
hazards that are similar to those presented by aerosol dispensers.
Therefore, the classification criteria and hazard information are the
same as for aerosols. OSHA recognizes that adopting this hazard
classification would bring some chemicals under the purview of the HCS
that currently are not covered (e.g., certain aerosols in refillable
containers). Should OSHA consider adopting the new hazard category of
chemicals under pressure in the aerosol chapter?
3. Appendix C (Based on the GHS Rev. 8)
    In this NPRM, OSHA is proposing to update a number of precautionary
statements to align with the GHS Rev. 7. However, the GHS Rev. 8
includes additional revisions to precautionary statements, most notably
an overhaul of the medical response precautionary statements (UN GHS,
2019, Document ID 0065). These precautionary statements were revised
for the GHS Rev. 8 because, among other reasons, manufacturers and
suppliers had difficulty choosing the appropriate wording where options
were given (e.g., choosing between calling a poison center or doctor,
or choosing between medical advice or attention) (UN GHS, 2019,
Document ID 0065).

                        Table XV--Revised Medical Response Statements From the GHS Rev. 8
----------------------------------------------------------------------------------------------------------------
                   Response precautionary
       Code              statements             Hazard class           Hazard category       Conditions for use
----------------------------------------------------------------------------------------------------------------
P316.............  Get emergency medical   Acute toxicity, oral    1, 2, 3...............  Competent Authority
                    help immediately.       (chapter 3.1).         1, 2, 3...............   or manufacturer/
                                           Acute toxicity, dermal  1, 2, 3...............   supplier may add,
                                            (chapter 3.1).         1, 1A, 1B, 1C.........   `Call' followed by
                                           Acute toxicity,                                  the appropriate
                                            inhalation (chapter                             emergency telephone
                                            3.1).                                           number, or the
                                           Skin corrosion                                   appropriate
                                            (chapter 3.2).                                  emergency medical
                                                                                help provider, for
                                                                                example, a Poison
                                                                                Centre, Emergency
                                                                                Centre or Doctor.
                                           Respiratory             1, 1A, 1B.............
                                            sensitization
                                            (chapter 3.4).
                                           Specific target organ   1, 2..................
                                            toxicity, single
                                            exposure; (chapter
                                            3.8).
                                           Aspiration hazard       1, 2..................
                                            (chapter 3.10).
P317.............  Get medical help......  Gases under pressure    Refrigerated liquefied
                                            (chapter 2.5).          gas.
                                           Acute toxicity, oral    4, 5..................
                                            (chapter 3.1).
                                           Acute toxicity, dermal  4, 5..................
                                            (chapter 3.1).
                                           Acute toxicity,         4, 5..................
                                            inhalation (chapter
                                            3.1).
                                           Skin irritation         2, 3..................
                                            (chapter 3.2).
                                           Serious eye damage      1.....................
                                            (chapter 3.3).
                                           Eye irritation          2/2A, 2B..............
                                            (chapter 3.3).
                                           Skin sensitization      1, 1A, 1B.............
                                            (chapter 3.4).
P318.............  If exposed or           Germ cell mutagenicity  1, 1A, 1B, 2..........
                    concerned, get          (chapter 3.5).
                    medical advice.
                                           Carcinogenicity         1, 1A, 1B, 2..........
                                            (chapter 3.6).

                                           Reproductive toxicity   1, 1A, 1B, 2..........
                                            (chapter 3.7).
                                           Reproductive toxicity,  Additional category...
                                            effects on or via
                                            lactation (chapter
                                            3.7).
P319.............  Get medical help if     Specific target organ   3.....................
                    you feel unwell.        toxicity, single
                                            exposure; respiratory
                                            tract irritation
                                            (chapter 3.8).
                                           Specific target organ   3.....................
                                            toxicity, single
                                            exposure; narcotic
                                            effects (chapter 3.8).
                                           Specific target organ   1, 2..................
                                            toxicity, repeated
                                            exposure (chapter
                                            3.9).
----------------------------------------------------------------------------------------------------------------

    As the new statements used in the GHS Rev. 8 provide standardized
language and do not require manufacturers and suppliers to decide which
statement is most appropriate, adopting these statements in the HCS as
part of this rulemaking might save manufacturers or importers time and/
or money compared to the existing statements. OSHA also believes that
these statements could improve hazard communication and worker safety
by more effectively conveying the type of medical action that is
necessary. OSHA seeks comments on the potential benefits or drawbacks
associated with adopting these revised medical response statements, or
other precautionary statements that are part of the GHS Rev. 8, as a
part of this rulemaking (see also Summary and Explanation, Section
XV.D. Appendix C). OSHA's existing enforcement policy, as described in
the OSHA hazard communication directive (OSHA, 2015, Document ID 0007),
addresses situations in which employers may use precautionary
statements from a more recent version of the GHS; does the policy
described in the directive provide sufficient flexibility?
Incorporation by Reference
    OSHA is proposing to revise the general incorporation by reference
section, 29 CFR 1910.6, to include updated test methods referenced in
the proposed revisions to the HCS. OSHA does not intend to require
chemicals already classified using an earlier version of a consensus
standard to be reclassified. OSHA believes that requiring the
reclassification of chemicals based on updated test methods could
result in unnecessary economic impacts and create unnecessary confusion
for stakeholders. OSHA is considering ways to clarify this in the final
regulatory text, e.g., by including a provision in the Dates section of
the rule stating that chemicals classified based on older test methods,
prior to the effective date of the rule, do not need to be
reclassified, and invites comments on this topic.

XV. Summary and Explanation of the Proposed Modifications to the Hazard
Communication Standard

    This section of the preamble explains OSHA's proposed changes to
the HCS (29 CFR 1910.1200). OSHA is proposing to align this
modification of the HCS with the GHS Rev. 7 (UN GHS, 2017, Document ID
0060). The agency has preliminarily decided to base most of the GHS
alignment on Rev. 7 for several reasons, even though Rev. 8 of the GHS
was issued in July 2019 (UN GHS, 2019, Document ID 0065). First, OSHA
began its work to update the standard prior to the release of Rev. 8.
While OSHA has always intended the HCS to be evergreen, preparation for
amending any standard is a time-consuming process and changing course
would have resulted in a significant delay to this rulemaking. Second,
the U.S.'s major trading partners (Canada, Europe, Australia, and New
Zealand) are all preparing to align with Rev. 7 (Canada, 2019, Document
ID 0172; Australia, 2020, Document ID 0168; New Zealand, 2018, Document
ID 0187; EC, 2019, Document ID 0176). Third, OSHA has discussed the
potential for adopting some of the most consequential changes from Rev.
8 in the Issues and Options section (see Section XIV, Issues and
Options Considered).
    In general, OSHA has received broad support for this rulemaking.
During OSHA's informal discussion with stakeholders in November 2016
about the potential changes to the HCS (Docket No. OSHA-2016-005), the
agency received feedback supporting continued alignment of the HCS with
the GHS and Health Canada, as well as support for addressing various
implementation issues under the existing HCS (API, 2016, Document ID
OSHA-2016-0005-0026; ACC, 2016, Document ID OSHA-2016-0005-0014; NGFA,
2016, Document ID OSHA-2016-0005-0018; AFIA, 2016, Document ID OSHA-
2016-0005-0017). The proposed changes are intended to improve and
enhance worker protection with regard to hazard communication by
incorporating new hazard classes and categories, improving and
streamlining precautionary statements, and providing additional
clarification of existing regulatory requirements. The following is a
discussion, by provision, of the proposed revisions to the standard.
    In the discussion of the proposed modifications to the appendices,
OSHA describes certain proposed changes that would affect multiple
hazard classes. OSHA discusses some changes in general terms and
indicates where those changes occur. However, to aid stakeholders, so
they can see the proposed changes in context, OSHA is placing in the
docket and on its website a redline strikeout version of all of the
proposed revisions to the current HCS and appendices (OSHA HCS Redline,
2020, Document ID 0222; https://www.osha.gov/dsg/hazcom/).

A. Incorporation by Reference

    OSHA is proposing to update the general incorporation by reference
section, 29 CFR 1910.6, to include the national/international consensus
standards listed below. OSHA does not intend to require chemicals
already classified using an earlier version of a consensus standard to
be reclassified. OSHA believes that requiring the reclassification of
chemicals based on updated test methods could result in unnecessary
economic impacts and create unnecessary confusion for stakeholders.
OSHA is considering ways to clarify this in the final regulatory text,
e.g., by including a provision in the DATES section of the rule stating
that chemicals classified based on older test methods, prior to the
effective date of the rule, do not need to be reclassified, and invites
comments on this topic.
    In places where OSHA is proposing to cite to new or updated
national/international consensus standards in the regulatory text and
appendix B, OSHA

is proposing to include the title, edition/version, and year of the
standard in the relevant reference for the benefit of stakeholders and
for ease of compliance. OSHA is not currently proposing to add/update
all existing references to consensus standards in the regulatory text
and appendix B, but recognizes that in some places in the existing text
consensus standards are cited without specific reference to the year,
edition, or full title of the relevant standard. In such cases,
stakeholders need to consult with Sec.  1910.6 to find more details
regarding the specific consensus standard that has been incorporated by
reference in the HCS. For example, appendix B, Section B.6.3 (Flammable
Liquids), incorporates by reference ASTM D1078, and Sec.  1910.6
specifies that the version of that standard incorporated by reference
is the one approved on May 15, 2005. Since there are many versions of
ASTM D1078 available, OSHA realizes that the general reference to ASTM
D1078 in appendix B could cause confusion to those classifying new
chemicals. OSHA is requesting comments on whether additional
information (year, edition/version, full title) should be added to all
of the references to consensus standards that are already incorporated
by reference in the HCS.
    OSHA is proposing to incorporate by reference (in Sec.  1910.6) the
materials below. A brief description of each consensus standard is
provided in the text below. A description of their use can be found in
the Regulatory Text, Appendices, and Summary and Explanation for the
Regulatory Text and Appendices (see Section XV.A and D) where the
standard is referenced. Each standard is available for purchase through
the publication agencies listed below:
 Regulatory Text--Paragraph c (Definitions)
    [cir] ASTM D 4359-90 (2019)--Standard Test Method for Determining
Whether a Material is a Liquid or a Solid, Re-approved 2019: This
consensus standard provides specific details regarding the test methods
used to determine whether a viscous material is a liquid or solid.
    [ssquf] ASTM, International: https://astm.org/Standard/standards-and-publications.html.
    [cir] European Agreement Concerning the International Carriage of
Dangerous Goods by Road (ADR): This consensus standard provides test
methods for determining the specific physical characteristics of a
liquid.
    [ssquf] https://shop.un.org/series/european-agreement-concerning-international-carriage-dangerous-goods-road-adr.
 Appendix B.1.3--Explosives
    [cir] UN ST/SG/AC.10/30/Rev.6, UN Recommendations on the Transport
of Dangerous Goods, Manual of Tests and Criteria, Part I: This
consensus standard provides test methods to determine if a substance
has explosive properties, the degree of sensitivity of the explosive
properties, and stability of explosive properties. The consensus
standard also provides information on the procedures for classification
of explosive materials.
    [ssquf] https://www.unece.org/tans/danger/publi/manual/maual_e.html.
 Appendix B.2.3--Flammable Gases
    [cir] 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: This consensus standard provides
specific details of the methods used to determine flammability of a gas
or gas mixture. The standard also provides methods for determining if a
gas or gas mixture is more or less oxidizing than air under atmospheric
conditions. The intention of the standard is for classifying gases and
gas mixtures as flammable gases and can be used to select the
appropriate gas cylinder valve outlet for the flammability
classification.
    [ssquf] International Organization for Standards; https://iso.org/store.html.
    [cir] ISO 817:2014 Refrigerants--Designation and safety
classification: This consensus standard establishes a safety
classification system based on the toxicity and flammability of the
refrigerant. It also provides guidance on how to determine a
refrigerant concentration limit.
    [ssquf] International Organization for Standards; https://iso.org/store.html.
    [cir] 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: This consensus standard provides guidance for
classification of gas-air mixtures and vapor-air mixtures under normal
conditions of pressure/temperature while also providing guidance on the
appropriate selection of equipment. In addition, the standard provides
guidance for determining the auto-ignition temperature of gas-air
mixtures and vapor-air mixtures with additional information provided to
guide selection of appropriate equipment for use in hazardous areas.
    [ssquf] International Electrotechnical Commission: https://iec.ch/index/htm#buy.
    [cir] DIN 51794 Determining the ignition temperature of petroleum
products: This consensus standard provides detailed information on test
methods used to determine the ignition temperature of petroleum
products. The standard applies to flammable gases and liquids in a
specific range of ignition temperature (75-650 [deg]C) with particular
emphasis on mineral oils hydrocarbons and their mixtures,
    [ssquf] German Institute of Standards: https://din.de/en/about-standards/buy-standards.
    [cir] UN ST/SG/AC.10/30/Rev.6, UN Recommendations on the Transport
of Dangerous Goods, Manual of Tests and Criteria, Part III: This
standard provides test methods for determining the flammability of
aerosols and gases. The standard provides additional information on the
criteria used in classifying gases with regards to their flammability.
    [ssquf] https://www.unece.org/tans/danger/publi/manual/maual_e.html.
 Appendix B.4--Oxidizing Gases
    [cir] 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: This consensus standard
provides specific details of the methods used to determine flammability
of a gas or gas mixture. The standard also provides methods for
determining if a gas or gas mixture is more or less oxidizing than air
under atmospheric conditions. The standard provides information on
criteria that may be used for classifying gases and gas mixtures as
flammable gases and may be used to select the appropriate gas cylinder
valve outlet for the flammability classification.
    [ssquf] https://www.iso.org/store.html.
 Appendix B.14.2--Oxidizing Solids
    [cir] UN ST/SG/AC.10/30/Rev.6, UN Recommendations on the Transport
of Dangerous Goods, Manual of Tests and Criteria, Part III: This
section of the standard provides detailed test methods for determining
the potential of a solid substance to increase the burning potential or
burning intensity of a combustible substance when the two are
thoroughly mixed. The standard also provides schematic with criteria on
classifying solid substances based on the oxidizing potential.
    [ssquf] https://www.unece.org/tans/danger/publi/manual/maual_e.html.
 Appendix B.17.2--Desensitized Explosives
    [cir] UN ST/SG/AC.10/30/Rev.6, UN Recommendations on the Transport
of

Dangerous Goods, Manual of Tests and Criteria, Part V: This section of
the Manual identifies criteria for classification of desensitized
explosives, and addresses the proper storage of these substances. The
standard provides testing criteria and guidance on classifying,
storing, and properly transporting goods according to their physical
hazards.
    [ssquf] https://www.unece.org/tans/danger/publi/manual/maual_e.html.
    [cir] UN ST/SG/AC.10/30/Rev.6, UN Recommendations on the Transport
of Dangerous Goods, Manual of Tests and Criteria, Part II: This
standard provides information on the definition of desensitized
explosives, the test methods used to evaluate a substance's ability to
suppress its explosive properties when thoroughly mixed as a homogenous
liquid and provides the criteria used to classify these substances
based on their desensitizing properties.
    [ssquf] https://www.unece.org/tans/danger/publi/manual/maual_e.html.
 Appendix B.17.3--Desensitized Explosives
    [cir] UN ST/SG/AC.10/30/Rev.6, UN Recommendations on the Transport
of Dangerous Goods, Manual of Tests and Criteria, Part II: This
standard provides information on the definition of desensitized
explosives, the test methods used to evaluate a substance's ability to
suppress its explosive properties when thoroughly mixed as a homogenous
liquid and provides the criteria used to classify these substances
based on their desensitizing properties.
    [ssquf] https://www.unece.org/tans/danger/publi/manual/maual_e.html.
    The proposed inclusion of UN ST/SG/AC.10/30/Rev.6, UN
Recommendations on the Transport of Dangerous Goods, Manual of Tests
and Criteria, in some sections of appendix B (B.1, B.2, B.3, B.4, B.14,
and B.17) would align with the GHS Rev. 7 (UN GHS, 2017, Document ID
0060). However, an earlier version of UN ST/SG/AC.10 (Rev. 4) was
incorporated by reference as part of the 2012 rulemaking and OSHA is
not currently proposing to update all of the Rev. 4 references to Rev.
6 as part of this rulemaking. OSHA requests comments on whether it
should, in the final rule, update all of the existing references to UN
ST/SG/AC.10/30 to Rev.6 or add Rev. 6 references to the existing Rev. 4
references such that they would be alternative options for compliance.
    UN ST/SG/AC.10/Rev.4 is included in the proposed regulatory text as
part of the revision to the structure of Sec.  1910.6(bb).
    Copies of the standards are available for purchase from the issuing
organizations at the addresses or through the other contact information
listed in Sec.  1910.6 for these private standards organizations. The
UN documents are available at no cost through the contact information
listed above. In addition, in accordance with Sec.  1910.6(a)(4), these
standards are available for inspection at any Regional Office of the
Occupational Safety and Health Administration (OSHA), or at the OSHA
Docket Office, U.S. Department of Labor, 200 Constitution Avenue NW,
Room N-3508, Washington, DC 20210; telephone:<PHONE_NUMBER> (TTY number:
877-889-5627). Due to copyright issues, OSHA cannot post consensus
standards on the OSHA website or through regulations.gov.

B. Regulatory Text

    OSHA has proposed numerous revisions to the HCS regulatory text.
The discussion of the proposed modifications is organized by paragraphs
to the regulatory text with each modification/addition, and the reasons
for and anticipated impact of each, described in detail below.
Stakeholders can examine the redline strikeout version of the
regulatory text at the OSHA HCS web page (https://www.osha.gov/dsg/hazcom/) or in the docket of this rulemaking (OSHA, 2020, Document ID
0222).
Paragraph (a) Purpose
    Existing paragraph (a)(1) of the HCS states that the purpose of the
standard is to ensure that the hazards of all chemicals produced or
imported are classified, and that information concerning the classified
hazards is transmitted to employers and employees. This provision
currently explains that the requirements of the standard are intended
to be consistent with the GHS Rev. 3. As the changes in this proposal
would align the HCS with the GHS Revision 7, OSHA proposes to change
the reference from Rev. 3 to Rev. 7.
Paragraph (b) Scope and Application
    The scope section of the HCS identifies the chemicals that are (and
are not) covered by the standard. Existing paragraph (b)(6)(x) excludes
nuisance particulates from the standard where the chemical manufacturer
or importer can establish that they do not pose any physical or health
hazard covered by the standard. OSHA proposes a slight revision to this
provision to make clear that nuisance particulates are excluded if they
do not pose any physical hazard, health hazard, or other hazards (i.e.,
hazard not otherwise classified (HNOC)) covered by the standard. This
proposal would clarify that all hazards covered by the standard must be
considered when evaluating nuisance particulates.
Paragraph (c) Definitions
    OSHA proposes to update three existing definitions and to add eight
new terms and definitions to the HCS. In addition, the agency is
proposing to eliminate one definition from the standard.
    OSHA is proposing to add a definition of the term Bulk Shipment to
the standard. The addition of this definition supports proposed
paragraph (f)(5)(ii), which clarifies labeling requirements for bulk
shipments of hazardous chemicals. The proposed definition would state
that ``bulk shipment'' means any hazardous chemical transported where
the mode of transportation (vehicle) comprises the immediate container
(e.g., contained in tanker truck, rail car, or intermodal container).
    OSHA is proposing to add the term Combustible Dust to the standard.
In updating the HCS in 2012, OSHA did not include a definition of
combustible dust because the agency was considering a combustible dust
rulemaking and the UNSCEGHS was also considering combustible dust
classification and communication issues (see 77 FR at 17705). However,
OSHA has not promulgated a combustible dust standard. Since 2012, the
UNSCEGHS has adopted a definition; the GHS Rev. 7 defines combustible
dust as ``finely divided solid particles of a substance or mixture that
are liable to catch fire or explode on ignition when dispersed in air
or other oxidizing media'' (definition adopted from ISO/IEC 80079-20-2
as referenced in UN GHS, 2017, Document ID 0060). OSHA has
preliminarily determined that this definition is consistent with
existing OSHA guidance on combustible dust hazards and proposes to
adopt this definition (OSHA, 2020, Document ID 0190; OSHA, 2009,
Document ID 0255). OSHA has several standards that use the term
``combustible dust,'' but do not define the term (e.g., Sec.  1910.272,
Grain Handling Facilities). OSHA believes the proposed definition of
the term for the HCS is consistent with the use of that term in those
other standards.
    OSHA is also proposing to revise the definition of exposure or
exposed. The definition currently provides, in relevant part, that
exposure or exposed means that an employee is subjected in the course
of employment to a chemical that is a physical or health hazard. OSHA
proposes to revise the definition to mean an employee is subjected in
the course of employment to a ``hazardous chemical,'' rather than to
``a chemical

that is a physical or health hazard,'' to clarify that the HCS covers
the hazards of all hazardous chemicals, including those considered to
be HNOCs.
    OSHA is proposing to include three new definitions for the terms
Gas, Liquid, and Solid. The agency is proposing to include these terms
to align with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060). Although
not included in the GHS, OSHA is proposing to add the temperature in
equivalent degrees Fahrenheit and pressure in equivalent pounds per
square inch (PSI) to the GHS definitions of gas and liquid because
those measurements are more commonly used in the U.S.
    Consistent with the GHS, OSHA proposes to define gas as a substance
which (i) at 122 [deg]F (50 [deg]C) has a vapor pressure greater than
43.51 PSI (300 kPa) (absolute); or (ii) is completely gaseous at 68
[deg]F (20 [deg]C) at a standard pressure of 14.69 PSI (101.3 kPa).
Also consistent with the GHS, OSHA proposes to adopt the definition of
liquid as a substance or mixture which at 1220F (50 [deg]C) has a vapor
pressure of not more than 43.51 PSI (300 kPa (3 bar)), which is not
completely gaseous at 680F (20 [deg]C) and at a standard pressure of
101.3 kPa, and which has a melting point or initial melting point of 68
0F (20 [deg]C) or less at a standard pressure of 14.69 PSI (101.3 kPa).
Furthermore, in accordance with the GHS, OSHA is proposing to include
the following as part of the definition of liquid: A viscous substance
or mixture for which a specific melting point cannot be determined
shall be subjected to ASTM D4359-90 (the Standard Test Method for
Determining Whether a Material Is a Liquid or a Solid (2019)); or to
the test for determining fluidity (penetrometer test) prescribed in
section 2.3.4 of Annex A of the European Agreement concerning the
International Carriage of Dangerous Goods by Road (ADR, 2019). Finally,
OSHA proposes to adopt the GHS definition of solid as a substance or
mixture which does not meet the definitions of liquid or gas.
    Although OSHA did not include these terms in the 2012 update to the
HCS, the agency is now proposing to include these definitions in order
to improve clarity and ensure consistency in hazard communication both
domestically and internationally. The agency anticipates that including
these terms in the standard will clarify provisions under appendices B
and D for classification of hazardous chemicals and preparation of
SDSs. OSHA does not anticipate that these new definitions will impact
other existing standards for construction or general industry. OSHA is
requesting comments on its preliminary decision to include these
definitions in this update.
    OSHA is proposing to update the definition of hazardous chemical to
delete the reference to pyrophoric gas because OSHA is proposing to
classify this hazard as a physical hazard in the flammable gas hazard
class (see discussion of proposed revisions to appendix B.2) and it is
no longer necessary to list it separately in the definition.
Concomitantly, OSHA is proposing to delete the separate definition for
pyrophoric gas.
    OSHA proposes to add a definition for immediate outer package to
mean the first packaging enclosing the container of hazardous chemical.
While all containers of chemicals must be labeled, as discussed in the
Summary and Explanation for paragraph (f), below, OSHA is proposing
revised labeling requirements for small containers. Proposed paragraph
(f)(12) would relax labeling requirements for small containers, but
would require complete label information on the ``immediate outer
package.'' For example, in the case of a kit, the container would be
whatever surrounds the chemical itself (e.g., a vial), and the
immediate outer package would be the first box or package surrounding
the container.
    The agency is also proposing to update the definition of physical
hazard to mean a chemical that is classified as posing one of the
following hazardous effects: Explosive; flammable (gases, liquids, or
solids); aerosols; oxidizer (liquid, solid or gas); self-reactive;
pyrophoric (liquid or solid); self-heating; organic peroxide; corrosive
to metal; gas under pressure; in contact with water emits flammable
gas; or desensitized explosive. The proposed definition also explicitly
states that the criteria for determining whether a chemical is
classified as a physical hazard are detailed in appendix B of the
standard. The proposal would make two substantive changes to the
current definition: (1) It would move the reference to aerosols out of
the parenthetical following the word ``flammable''; and (2) it would
add a reference to desensitized explosives. These proposed revisions
are intended to reflect the proposed new hazard classes for aerosols
and desensitized explosives in appendix B in accordance with the GHS
Rev. 7. These changes are discussed in greater detail in the Summary
and Explanation of appendix B.
    OSHA is proposing to add a definition of Physician or other
licensed health care professional (PLHCP) to the standard. OSHA
proposes to define this term as an individual whose legally permitted
scope of practice (i.e., license, registration, or certification)
allows the individual to independently provide or be delegated the
responsibility to provide some or all of the health care services
referenced in paragraph (i) of the standard. The new definition is
necessary in light of OSHA's proposal to replace the phrase ``physician
and nurse'' in paragraph (i), trade secrets with the term ``PLHCP'' to
be consistent with other OSHA standards that use the term PLHCP, and to
better reflect current medical practices. That change is discussed in
greater detail in the Summary and Explanation of paragraph (i). OSHA
believes the proposed definition of ``PLHCP'' is consistent with the
way the agency has defined that term in all health standards
promulgated since the bloodborne pathogen standard, 29 CFR 1910.1030,
in 1991.
    OSHA is also proposing to add a new definition, released-for-
shipment, to mean a chemical that has been packaged and labeled in the
manner in which it will be distributed or sold. This is a new term OSHA
is proposing to use in paragraphs (f)(1) and (11) related to updating
labels when new hazard information becomes available. OSHA notes that
this definition is similar, but not identical to, the definition used
by the U.S. Environmental Protection Agency's (EPA's) Pesticide
Registration and Classification Procedures regulation, 40 CFR 152.3.
EPA defines a product as released for shipment when the producer has
packaged and labeled it in the manner in which it will be distributed
or sold, or if it is stored in an area where finished products are
ordinarily held for shipment. OSHA is not proposing to include
chemicals that are stored in an area where finished products are
usually held (but not packaged and labeled) in the definition of
``released for shipment'' because there do not appear to be any
feasibility issues with ensuring that such chemicals are labeled with
the most updated information. The agency is requesting comments on
whether the proposed definition is appropriate for application to the
HCS. OSHA is also interested in understanding whether the slight
differences between OSHA's and EPA's definitions will pose any
compliance issues for entities dealing with both OSHA and EPA labeling
requirements. See the discussion of the proposed revisions to paragraph
(f) for additional details.
Paragraph (d) Hazard Classification
    OSHA is proposing two changes to paragraph (d)(1). OSHA proposes to
revise the second sentence of paragraph

(d)(1) to read that for each chemical, the chemical manufacturer or
importer shall determine the hazard classes, and where appropriate, the
category of each class that apply to the chemical being classified
under normal conditions of use and foreseeable emergencies. The
language OSHA is proposing to add at the end of that sentence (``under
normal conditions of use and foreseeable emergencies'') simply
reiterates the scope language currently in paragraph (b)(2) and OSHA's
longstanding position that hazard classification must cover the normal
conditions of use and foreseeable emergencies. As OSHA explained in its
compliance directive for the HCS (OSHA, 2015, Document ID 0007), for
example, known intermediates, by-products, and decomposition products
that are produced during normal conditions of use or in foreseeable
emergencies must be addressed in the hazard classification.
    OSHA also proposes to add a new sentence to paragraph (d)(1)
stating that the hazard classification shall include any hazards
associated with a change in the chemical's physical form or resulting
from a reaction with other chemicals under normal conditions of use.
OSHA believes this language is necessary because there has been some
confusion about whether chemical reactions that occur during normal
conditions of use must be considered during classification. The
agency's intent has always been to require information on SDSs that
would identify all chemical hazards that workers could be exposed to
under normal conditions of use and in foreseeable emergencies (see
paragraph (b)(2)). This issue has been raised, for instance, when
multiple chemicals are sold together with the intention that they be
mixed together before use. For example, epoxy syringes contain two
individual chemicals in separate sides of the syringe that are mixed
under normal conditions of use. While OSHA intends for the hazards
created by the mixing of these two chemicals to be considered in
classification, those hazards need only appear on the SDS (see appendix
D to Sec.  1910.1200--Safety Data Sheets, section 3) and not on the
label. For additional information, please see the Summary and
Explanation for appendix D.
Paragraph (e) Written Hazard Communication Plan
    OSHA is proposing a minor editorial correction in paragraph (e)(4).
OSHA has found that an inadvertent misprint occurred in the print
version of the CFR. Specifically, in the print version of the CFR,
paragraph (e)(4) references Sec.  1910.20 instead of Sec.  1910.1020.
Notably, this error is reflected only in the print version of the CFR;
the eCFR (www.ecfr.gov) is correct. OSHA proposes to fix this error so
that the print and electronic versions of the standard are the same.
Paragraph (f) Labels and Other Forms of Warning
    Paragraph (f) of the HCS provides requirements for labeling. OSHA
is proposing to modify paragraphs (f)(1), (5), and (11), and is also
proposing a new paragraph (f)(12).
    Paragraph (f)(1), Labels on shipped containers, currently specifies
what information is required on shipped containers of hazardous
chemicals and also provides that HNOCs do not have to be addressed on
the containers. OSHA proposes to revise paragraph (f)(1) to provide
that, in addition to HNOCs, hazards resulting from a reaction with
other chemicals under normal conditions of use do not have to be
addressed on shipped containers. OSHA believes this information is not
appropriate on containers because it might confuse users about the
immediate hazards associated with the chemical in the container.
However, information on hazards resulting from a reaction with other
chemicals under normal conditions of use is important for downstream
users, and OSHA is not proposing to change the existing requirements
for these hazards to be indicated on SDSs (under appendix D) and
addressed in worker training where applicable (under paragraph (h)).
OSHA also proposes to add the word ``distributor'' to the third
sentence of paragraph (f)(1) to make it consistent with the first
sentence.
    In new paragraph (f)(1)(vii), OSHA is proposing to add a
requirement that the label include the date a chemical is released for
shipment. The agency is proposing this change in conjunction with
changes in paragraph (f)(11) related to relabeling of containers that
are released for shipment but have not yet been shipped. Providing the
date a chemical is released for shipment on the label would allow
manufacturers and distributors to more easily determine their
obligations when new hazard information becomes available.
    Paragraph (f)(5) specifies label requirements that apply to the
transport of hazardous chemicals from workplace to workplace. OSHA
proposes to add the heading ``Transportation'' to this paragraph and to
add two new paragraphs to (f)(5) that specify requirements related to
transportation of hazardous chemicals.
    OSHA is proposing to add new paragraph (f)(5)(ii) to address the
transport of bulk shipments of hazardous chemicals (e.g.,, in tanker
trucks or rail cars). The proposed paragraph would specify that labels
for bulk shipments of hazardous chemicals may either be on the
immediate container or may be transmitted with shipping papers, bills
of lading, or other technological or electronic means so that the
information is immediately available in print to workers on the
receiving end of the shipment. The proposed paragraph would codify
policy from a 2016 guidance document that OSHA created jointly with
DOT's Pipeline Hazardous Materials Safety Administration (PHMSA), with
the intent of providing stakeholders with clarity for how to properly
label bulk chemicals in transport (PHMSA, 2016, Document ID 0244). OSHA
requests comments on whether it is appropriate to add proposed
paragraph (f)(5)(ii) to the HCS and whether the addition of that
paragraph would provide clarity regarding labeling of bulk chemical
shipments.
    Under the current HCS, appendix C, paragraph C.2.3.3 provides that
where a pictogram required by the DOT appears on a shipped container,
the HCS pictogram for the same hazard (specified in C.4) shall not
appear. This provision was intended to prevent confusion associated
with having two different representations of the same hazard on the
container (77 FR 17728). However, after learning that DOT updated its
regulations to indicate that it does not consider the HCS pictogram to
conflict with the DOT pictogram, OSHA no longer believes that having
both pictograms will create confusion for workers handling the
chemical. Accordingly, OSHA proposes to: (1) Delete the language
currently in paragraph C.2.3.3 from appendix C; and (2) adopt new
paragraph (f)(5)(iii) to provide that where a DOT pictogram appears on
a label for a shipped container, the appendix C pictogram for the same
hazard is allowed, but is not required, on the HCS label.
    For example, in the case where a chemical is shipped in only its
immediate container, such as a 55-gallon drum containing a flammable
liquid, both a DOT label and an OSHA-compliant label would be required.
Under the current standard, the flame pictogram on the OSHA-compliant
label would be prohibited because the DOT label would contain the
equivalent pictogram. The proposed rule would allow, but not require,
the flame pictogram to appear on the OSHA-compliant label. This means
chemical

manufacturers could use the same labels for shipping containers and for
containers that are solely used in the workplace; this would avoid
information loss and eliminate the need to develop or print additional
labels.
    Paragraph (f)(11) currently requires that chemical manufacturers,
importers, distributors, or employers who become newly aware of any
significant information regarding the hazards of a chemical revise the
labels within six months of becoming aware of the new information and
ensure that labels on containers of hazardous chemicals shipped after
that time contain the new information. OSHA recognizes that, on some
occasions, a chemical manufacturer or importer may become aware of
significant hazard information after a chemical has already been
labeled but before it ships. Therefore, OSHA proposes to add a sentence
to paragraph (f)(11) providing that chemicals that have been released
for shipment and are awaiting future distribution need not be
relabeled; however, the proposed sentence also states that the chemical
manufacturer or importer must provide the updated label for each
individual container with each shipment. The purpose of this proposal
is to account for the long distribution cycles of some products and the
potential hazards workers could face in relabeling the immediate
containers of hazardous chemicals that have already been prepared for
shipment.
    Following publication of the 2012 updates to the HCS, OSHA received
feedback related to difficulties some chemical manufacturers were
having complying with paragraph (f)(11), particularly in the case of
chemicals that travel through long distribution cycles (Kenyon, 2017,
Document ID 0182). Many products have straightforward supply chains and
are packaged, labeled, and promptly shipped downstream. Other products,
for example in the agrochemical sector, are packaged and labeled when
they leave the chemical manufacturer's facility, but they may reside at
a warehouse or distribution facility for extended periods of time
(e.g.,, several years) before being shipped downstream. There are also
instances where products may be returned from the downstream users to
the distribution facility and then shipped to other customers (NGFA,
2016, Document ID OSHA-2016-0005-0018; AFIA, 2016, Document ID OSHA-
2016-0005-0017).
    The act of relabeling these products in warehouses or distribution
facilities has the potential to pose occupational safety and health
risks to employees. Relabeling each individual container may require
that employees open already secure packaging, a process that may result
in potential chemical exposures. Furthermore, OSHA believes re-labeling
of sealed hazardous chemical containers is not a common practice in
warehouses and that warehouses may lack the equipment necessary to
relabel products in a safe and effective manner.
    OSHA has previously recognized the complexities involved with
relabeling existing stock of hazardous chemicals. Following
promulgation of the 2012 updates to the HCS, the HCS compliance
directive (OSHA, 2015, Document ID 0007) provided enforcement guidance
on the labeling of existing stock. Before June 1, 2015 (for
manufacturers and importers), and before December 1, 2015 (for
distributors), OSHA permitted chemical manufacturers, importers, and
distributors with existing stock that was packaged (e.g.,, boxed,
palletized, shrink wrapped, etc.) for shipment and labeled in
accordance with the pre-2012 version of the HCS to ship those
containers downstream without relabeling the containers with HCS 2012-
compliant labels. However, the chemical manufacturer or importer
generally had to provide an HCS 2012-compliant label for each
individual container shipped and the appropriate HCS 2012-compliant
SDS(s) with each shipment. After June 1, 2015, chemical manufacturers
and importers of hazardous chemicals were required to ensure that each
container was labeled with an HCS 2012-compliant label prior to
shipping, and all distributors were generally required to ensure any
chemicals shipped after December 1, 2015, were labeled in accordance
with the 2012 updates to the HCS. OSHA used this enforcement policy as
a basis for the proposed revisions to paragraph (f)(11).
    OSHA has preliminarily determined that the proposed changes to
paragraph (f)(11) would adequately address issues with long
distribution cycles while still ensuring chemical users receive the
most current hazard information. OSHA invites comments on the proposed
revisions to this paragraph. In particular, OSHA requests comments on
whether the proposed changes would adequately address issues associated
with relabeling in cases of long distribution cycles, whether the
proposed changes would provide sufficient flexibility, and whether the
proposed revisions would alleviate safety concerns that would otherwise
be associated with the relabeling of packaged stock.
    OSHA is proposing a new paragraph, (f)(12), to address small
container labeling. Currently, the HCS requires that all shipped
containers be labeled with the information specified in paragraph
(f)(1). The HCS, as updated in 2012, requires considerably more
information on the label than the standard required previously; labels
must include all hazards, as well as pictograms and precautionary
statements. Many stakeholders have told OSHA that they have
difficulties including all of the required information from paragraph
(f)(1) on the labels they use for small containers. In some cases, the
information becomes too small for a person to read it, and while it is
sometimes possible to use alternate types of labels (such as pull-out
labels or tags), it is not always feasible to do so (Watters, 2013,
Document ID 0200; Collatz, 2015, Document ID 0174; Blankfield, 2017,
Document ID 0170). In response to these concerns, through letters of
interpretation and the HCS directive (OSHA, 2015, Document ID 0007;
Watters, 2013, Document ID 0200; Collatz, 2015, Document ID 0174;
Blankfield, 2017, Document ID 0170), OSHA provided a practical
accommodation to address situations where it is infeasible to provide
all HCS-required label information directly on small containers through
the use of pull-out labels, fold-back labels, or tags. The practical
accommodation allows limited information to be included on the small
container label, but requires complete label information to be provided
on the outside packaging. OSHA proposes to incorporate this practical
accommodation into the standard in new paragraph (f)(12).
    OSHA is proposing that all of the small container labeling
provisions apply only where the chemical manufacturer, importer, or
distributor can demonstrate that it is not feasible to use pull-out
labels, fold-back labels, or tags containing the full label information
required by paragraph (f)(1). Proposed paragraph (f)(12)(ii)(A) through
(E) would provide that labels on small containers that are less than or
equal to 100 milliliter (ml) capacity must include, at minimum: Product
identifier; pictogram(s); signal word; chemical manufacturer's name and
phone number; and a statement that the full label information for the
hazardous chemical is provided on the immediate outer package.
Additionally, proposed paragraph (f)(12)(iii) would provide that no
labels are required for small containers of 3 ml capacity or less where
the chemical manufacturer, importer, or distributor can demonstrate
that any label would interfere with the normal use of the container;
however,

that same proposed paragraph would state that if no label is required,
the container must bear, at minimum, the product identifier. For
example, the product identifier (e.g., CAS number) could be etched on a
3 ml glass vial (container) to ensure that the identifier remains fixed
to the vial. This type of identification would ensure that the chemical
in the small container can be identified and matched with the
chemical's full label information.
    Proposed paragraph (f)(12)(iv) would provide that for any small
container covered by paragraph (f)(12)(ii) or (iii), the immediate
outer package must include the full label information required by
paragraph (f)(1) for each hazardous chemical in the immediate outer
package, along with a statement that the small container(s) inside must
be stored in the immediate outer package bearing the complete label
when not in use. This proposed paragraph would also state that labels
affixed to the immediate outer package must not be removed or defaced,
as required by existing paragraph (f)(9).
    OSHA believes that proposed paragraph (f)(12) would provide
chemical manufacturers, importers and distributors with flexibility in
labeling small containers. The proposed paragraph is consistent with
the small packaging examples provided in the GHS Annex 7: Examples of
Arrangements of the GHS Label Elements (UN GHS, 2016, Document ID
0197), and would result in better alignment with Health Canada's
Hazardous Product Regulations (HPR) small capacity container
requirements (Health Canada, 2015, Document ID 0051). Specifically, the
HPR, under 5.4(1), provides exemptions from certain labeling
requirements (such as precautionary statements) for small capacity
containers of 100 ml or less. In addition, under 5.4(2), the HPR
provides labeling exemptions for containers of 3 ml or less if the
label interferes with the normal use of the hazardous product. OSHA
requests comments on the feasibility of the proposed small container
labeling provisions. The agency also requests feedback about whether
the proposed changes would improve safe handling and storage for
chemicals in small containers.
Paragraph (g) Safety Data Sheets
    SDSs provide important safety information to employers and
employees on the use of hazardous chemicals in the workplace.
Additionally, SDSs provide detailed technical information and serve as
a reference source for exposed employees, industrial hygienists, safety
professionals, emergency responders, health care professionals, and
other interested parties. While OSHA believes that information in SDSs
has greatly improved with the standardized, 16-section format
prescribed in the 2012 updates to the HCS, the agency is proposing two
minor changes to paragraph (g) to ensure consistency and accessibility
of the SDSs.
    The proposed revisions to paragraph (g) are confined to paragraphs
(g)(2) and (10). The purpose of paragraph (g)(2) is to identify what
information must be included on an SDS. The first part of existing
paragraph (g)(2) states that the chemical manufacturer or importer
preparing the SDS shall ensure that it is in English. However, as
permitted by paragraph (g)(1), some chemical manufacturers and
importers may obtain, rather than prepare, SDSs. To minimize any
potential confusion between paragraphs (g)(1) and (2), OSHA is
proposing to revise paragraph (g)(2) by removing the reference to
preparing the SDS. The first part of the first sentence in paragraph
(g)(2) would be revised to read simply that the chemical manufacturer
or importer shall ensure that the SDS is in English. This is a
technical clarification intended to ensure consistency with paragraph
(g)(1).
    Paragraph (g)(10) addresses the form and storage of SDSs. The
original intent of paragraph (g)(10) was to allow employers
alternatives to SDSs within a plant site (see 48 FR 53337).
Alternatives to SDSs, such as written operating procedures and manuals,
are generally permitted. Existing paragraph (g)(10) also permits
employers to design SDSs to cover groups of hazardous chemicals in a
work area where it may be more appropriate to address the hazards of a
process rather than individual chemicals. In any case, paragraph
(g)(10) requires the employer to ensure that the required information
is provided for each hazardous chemical and is readily accessible to
employees. However, with the update to the HCS in 2012, OSHA changed
the requirements of the SDS from a performance-oriented format to a
standardized format. Standardizing the SDS format improved hazard
communication by ensuring users could quickly find relevant information
(see 77 FR 17596-98). Because SDSs now have a standardized format and
are specific to individual hazardous chemicals, they are not permitted
to be designed to cover groups of hazards, as currently provided in
paragraph (g)(10). Therefore, OSHA is proposing a change to paragraph
(g)(10) that would allow SDSs to be stored, rather than designed, in a
way to cover groups of hazardous chemicals in a work area. OSHA
believes that this change would allow employers flexibility in how they
keep SDSs in the workplace while also ensuring that the mandatory 16-
section SDS is maintained. The agency is requesting comments regarding
whether this proposed revision would require stakeholders to make any
significant changes to their current practices.
Paragraph (i) Trade Secrets
    This paragraph describes certain conditions under which a chemical
manufacturer, importer, or employer may withhold the specific chemical
identity (e.g., chemical name), other specific identification of a
hazardous chemical, or the exact percentage (concentration) of the
substance in a mixture, from the SDS. OSHA is proposing three
significant changes within paragraph (i)(1) and the paragraphs
thereunder. First, OSHA is proposing to revise paragraph (i)(1) to
allow for concentration ranges to be claimed as a trade secret and to
specify that it is section 3 of the SDS from which trade secret
information may be withheld.
    Second, OSHA is proposing new paragraph (i)(1)(iv), which would
require that when an ingredient's exact concentration or concentration
range is claimed as a trade secret, the SDS must provide the
ingredient's concentration as a concentration range selected from a
prescribed list of ranges. These ranges are in proposed paragraphs
(i)(1)(iv)(A) through (M) as follows: (1) From 0.1% to 1%; (2) from
0.5% to 1.5%; (3) from 1% to 5%; (4) from 3% to 7%; (5) from 5% to 10%;
(6) from 7% to 13%; (7) from 10% to 30%; (8) from 15% to 40%; (9) from
30% to 60%; (10) from 45% to 70%; (11) from 60% to 80%; (12) from 65%
to 85%; and (13) from 80% to 100%. These ranges are consistent with
those used in Canada, first described under the WHMIS 1988 Controlled
Products Regulation (CPR) and re-implemented in 2018 under the HPR
(Canadian Gazette II, 2018, Document ID 0101). Using the same
concentration ranges as Canada, one of the U.S.'s major trading
partners, is part of the two countries' efforts through the Regulatory
Cooperation Council to align hazard communication to the greatest
extent possible.
    OSHA has received numerous inquiries about the use of trade secrets
for concentration ranges (Colau, 2017, Document ID 0098; Nelson, 2017,
Document ID 0099). Although chemical manufacturers and importers are
permitted to use concentration ranges rather than an exact percentage
on the

SDS when there is batch-to-batch variability in the production of a
mixture or for a group of substantially similar mixtures with similar
chemical composition, OSHA does not currently allow trade secret status
for a concentration range (see 77 FR 17731). However, in response to
feedback from stakeholders who have indicated that there are instances
where a concentration range is also a trade secret, OSHA has
preliminarily determined it is appropriate to permit concentration
ranges to be claimed as trade secrets as long as the ranges prescribed
in proposed paragraphs (i)(1)(iv)(A) through (M) are used (Nelson,
2017, Document ID 0099; Colau, 2017, Document ID 0098).
    Third, proposed new paragraph (i)(1)(v) would require that the
concentration range used on the SDS be the narrowest range possible.
This proposed paragraph would also provide that if the actual
concentration range falls between 0.1% and 30% and does not fit
entirely into one of the prescribed ranges in proposed paragraphs
(i)(1)(iv)(A) through (G), a single range created by the combination of
two applicable consecutive ranges between (i)(1)(v)(A) and (G) may be
disclosed instead, provided that the combined concentration range does
not include any range that falls entirely outside the exact range in
which the ingredient is present. For example, a chemical manufacturer
that wishes to claim the concentration of a specific ingredient (e.g.,
2.5%) as a trade secret would have to use the prescribed range in
proposed paragraph (i)(1)(iv)(C) of 1% to 5%. If the ingredient is in
the mixture at a concentration range of 0.9% to 2%, then the chemical
manufacturer could combine the prescribed ranges in proposed paragraphs
(i)(1)(iv)(B) and (C), resulting in a range of 0.5% to 5% on the SDS.
If the ingredient is in the mixture at a concentration range of 5% to
7%, the chemical manufacturer would have to use the range in proposed
paragraph (i)(1)(iv)(D) of 3% to 7%, because it is narrower than the
range in proposed paragraph (i)(1)(iv)(E) of 5% to 10%.
    OSHA is requesting comments on the proposed revisions to paragraph
(i)(1). Specifically, the agency is interested in any experience
stakeholders have had with developing SDSs using the prescribed
concentration ranges and any concerns stakeholders have about using
concentration ranges on SDSs. The agency is also requesting comments
addressing the adequacy of hazard information provided by these ranges.
Do these ranges provide sufficient information for downstream chemical
manufacturers to conduct hazard classifications? Are the ranges listed
in proposed paragraphs (i)(1)(iv)(A) through (M) too wide (should they
be narrowed)? Should OSHA allow combinations among all ranges (e.g.,
(i)(1)(v)(A) through (M)) or should the allowance for combining ranges
be even more restrictive than proposed (e.g., (i)(1)(v)(A) through
(E))?
    OSHA is also proposing other changes in paragraph (i) to reflect
the proposal to permit concentration ranges to be claimed as trade
secrets and to adopt the ``PLHCP'' terminology in lieu of references to
``physician or nurse.'' See discussion of proposed changes to paragraph
(c), Definitions, where OSHA explains that it is proposing to replace
the phrase ``physician and nurse'' with ``PLHCP'' to be consistent with
other OSHA standards and to better reflect current medical practices.
The specific changes OSHA is proposing are as follows:
     OSHA is proposing to revise paragraph (i)(1)(iii) to
change ``percentage'' to ``concentration or concentration range.''
     OSHA is proposing to move existing paragraph (i)(1)(iv) to
paragraph (i)(1)(vi) and to change ``percentage'' to ``exact
concentration or concentration range.''
     In paragraph (i)(2), OSHA is proposing to change
``physician or nurse'' to ``PLHCP'' and to replace ``percentage of
composition'' with ``concentration or concentration range.''
     OSHA is proposing to revise paragraph (i)(3) to change
``percentage composition'' to ``exact concentration or concentration
range'' and to change the parenthetical from ``(i.e., physician,
industrial hygienist, toxicologist, epidemiologist, or occupational
health nurse)'' to ``(e.g., PLHCP, industrial hygienist, toxicologist,
or epidemiologist).''
Paragraph (j) Dates
    OSHA is proposing to implement the revised provisions over a two-
year phase-in period. OSHA proposes that the revisions become effective
60 days after the publication date (paragraph (j)(1)) and that chemical
manufacturers, importers, and distributors evaluating substances comply
with all modified provisions of the HCS no later than one year after
the effective date (paragraph (j)(2)). OSHA also proposes that chemical
manufacturers, importers, and distributors evaluating mixtures comply
with all modified provisions no later than two years after the
effective date (paragraph (j)(3)).
    Proposed paragraph (j) would replace the regulatory text currently
in paragraph (j), as the dates specified in existing paragraph (j) have
all passed. This proposed paragraph is based in part on stakeholder
comments and the agency's experience implementing the 2012 updates to
the HCS. In 2012, OSHA did not stagger the compliance dates for
substances and mixtures; however, OSHA believes that such a tiered
approach may ease the compliance burden for manufacturers of mixtures
that may rely on the hazard information in the SDSs from their
ingredient suppliers to update the labels and SDSs for the mixtures.
The changes OSHA is proposing in this update are far less complicated
than the 2012 revision and would result in no change in hazard
classification for the vast majority of chemicals. Additionally, the
proposed update to paragraph (f)(11) addressing relabeling requirements
for chemicals that have been released for shipment would also reduce
the need for a lengthier implementation period. OSHA is requesting
comments regarding the adequacy and appropriateness of the proposed
compliance dates and on the feasibility of implementing a tiered
compliance approach for substances and mixtures.

C. Appendix A

    OSHA is proposing to update appendix A in several respects. The
proposed changes are discussed in order of revisions to specific health
hazards in appendix A, followed by general changes to definitions and
terminology, clarification of mandatory requirements, and corrections.
OSHA preliminarily concludes that all of the proposed changes to
appendix A will improve classification and communication of hazards and
thus better protect workers. Many of the proposed changes would align
the HCS with the GHS Rev. 7. Aligning the HCS with the GHS would ease
compliance burdens for U.S. stakeholders who must also comply with
international requirements for hazard classification and communication.
    OSHA is providing a redline strikeout version of appendix A, which
reflects all of OSHA's proposed revisions, 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, as the discussion below does not fully
describe all of the non-substantive or editorial changes OSHA is
proposing.

Revisions to Health Hazards in Appendix A
General Classification Considerations
    In Paragraph A.0.1, OSHA proposes to add a note from Paragraph
<IP_ADDRESS>.3 of the GHS Rev. 7 (UN GHS, 2017, Document ID 0060), providing
that where impurities, additives, or individual constituents of a
substance or mixture have been identified and are themselves
classified, they should be taken into account during classification if
they exceed the cut-off value/concentration limit for a given hazard
class. OSHA did not include this note in the HCS in 2012 because the
definition of ``substance'' in paragraph (c) references additives and
impurities, and therefore the classification of substances necessarily
takes impurities and additives into account. Nonetheless, the agency
now believes that this note is useful to align with the GHS and has
added this note as proposed A.0.1.3. Including this provision would
clarify that manufacturers and importers must consider the hazards of
all classified components when classifying chemicals. This would help
ensure accurate classification of chemicals and therefore improve
protections for workers.
    OSHA also proposes to modify the introduction of paragraph A.0.4.1
to include mandatory language. The current text indicates that the
sequence in the process of classification of mixtures is recommended.
OSHA proposes to revise A.0.4.1 to read ``Except as provided in
A.0.4.2, the process of classification of mixtures is based on the
following sequence'' to specify that this process is mandatory.
Acute Toxicity--(Appendix A.1)
    In appendix A.1, OSHA proposes to revise the definition of acute
toxicity to refer to serious adverse health effects (i.e., lethality)
occurring after a single or short-term oral, dermal, or inhalation
exposure to a substance or mixture. (The current definition refers to
adverse effects occurring following oral or dermal administration of a
single dose of a substance, or multiple doses given within 24 hours, or
an inhalation exposure of 4 hours.) This change is being proposed to
align with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS,
2016, Document ID 0131).
    OSHA also proposes to revise the classification criteria for
substances in A.1.2.1 to note that while some in vivo methods determine
LD50/LC50 values directly, other newer in vivo
methods (e.g., using fewer animals) consider other indicators of acute
toxicity, such as significant clinical signs of toxicity, which are
used by reference to assign the hazard category. This change is being
proposed to align with classification criteria in the GHS Rev. 7 (UN
GHS, 2017, Document ID 0060; UN GHS, 2016, Document ID 0131).
    OSHA is also proposing slight revisions to Table A.1.1, ``Acute
toxicity hazard categories and acute toxicity estimate (ATE) values
defining the respective categories'', to align with the GHS Rev. 7 (UN
GHS, 2017, Document ID 0060; UN GHS, 2016, Document ID 0131). The GHS
presents the ATE range in Table A.1.1 using the term ``ATE'' to express
the range, while the HCS currently uses the term ``AND.'' Therefore,
OSHA proposes to change the ``AND'' in the acute toxicity estimate
(ATE) ranges to ``ATE'' to align with the GHS Rev. 7. This modification
would not change the classification criteria itself, but would be more
technically accurate and consistent with the way the table is expressed
in the European Commission's (EC) Classification, Labelling, and
Packaging of Substances and Mixtures (CLP) regulation (ECHA, 2017,
Document ID 0256).
    In paragraph A.1.2.3, OSHA proposes to include a new sentence at
the end of the paragraph to clarify that both data from animal tests
and human studies should be considered in evaluating acute toxicity.
The new text states that in cases where data from human experience
(i.e., occupational data, data from accident databases, epidemiology
studies, clinical reports) is also available, it should be considered
in a weight of evidence approach consistent with the principles
described in A.0.3. To ensure human data is considered in classifying
chemicals for all acute toxicity hazard categories, the GHS added this
clarifying text in paragraph <IP_ADDRESS> (UN GHS, 2016, Document ID 0131).
OSHA is proposing these changes to paragraph A.1.2.3 to align with the
GHS Rev. 7.
    OSHA also proposes a new paragraph A.1.2.4, which is intended to
correspond to Chapter 3.1, (paragraph <IP_ADDRESS>.5) in the GHS Rev. 7 (UN
GHS, 2017, Document ID 0060). This proposed paragraph would provide
that in addition to classification for inhalation toxicity, if data are
available that indicate that the mechanism of toxicity was corrosivity
of the substance or mixture, the classifier must consider whether the
chemical is corrosive to the respiratory tract. This proposed paragraph
would clarify that the hazard corrosive to the respiratory tract is
covered under the HCS. OSHA did not explicitly include the corrosive to
the respiratory tract hazard in the HCS in 2012, but explained in OSHA
3844: Hazard Communication: Hazard Classification Guidance for
Manufacturers, Importers and Employers (OSHA, 2016, Document 0008) that
this hazard should be considered during classification. The Hazard
Classification guidance explains that if the classifier has data
indicating that there is acute inhalation toxicity with corrosion of
the respiratory tract that leads to lethality, then the substance or
mixture may be labeled with the additional hazard statement ``corrosive
to the respiratory tract.'' However, if the classifier has data that
indicates acute inhalation toxicity with corrosion of the respiratory
tract and the effect does not lead to lethality, then the hazard may be
addressed in the Specific Target Organ Toxicity hazard classes (see
appendices A.8 and A.9). OSHA is including these clarifications in
proposed A.<IP_ADDRESS> and A.<IP_ADDRESS>, but is modifying the ``may'' language
from the guidance to ``must'' language to ensure that corrosive to the
respiratory tract is appropriately considered during the classification
process.
    In Figure A.1.1 and paragraph A.<IP_ADDRESS>.2, OSHA proposes to correct
the cross-reference from A.<IP_ADDRESS>.3 to A.<IP_ADDRESS>.4. OSHA also proposes
to amend paragraph A.<IP_ADDRESS>.3. If a mixture contains an ingredient of
unknown acute toxicity at a concentration of at least 1 percent,
paragraph A.<IP_ADDRESS>.3 currently requires a statement that ``X'' percent
of a mixture consists of ingredient(s) of unknown toxicity on the label
and SDS. OSHA proposes to revise this paragraph to require the
statement to differentiate by route of exposure. For example, the
statement(s) could read, ``x % of the mixture consists of ingredient(s)
of unknown acute oral toxicity'' or ``x % of the mixture consists of
ingredient(s) of unknown acute dermal toxicity.'' Given that it is
possible to have unknown ingredients for more than one relevant route
of exposure (e.g., oral, dermal, inhalation), differentiating the
statement by route would be helpful to chemical users. This proposed
change would align with paragraph <IP_ADDRESS>.2.2 in the GHS Rev. 7 (UN
GHS, 2017, Document ID 0060; UN GHS, 2010, Document 0089).
    OSHA also proposes to delete the second paragraph in A.<IP_ADDRESS>.3
because it is duplicative of the first paragraph.
Skin Corrosion/Irritation and Serious Eye Damage/Eye Irritation--
(Appendices A.2 and A.3)
    OSHA is proposing more extensive revisions to the sections on skin
corrosion/irritation and serious eye

damage/irritation (appendices A.2 and A.3) than it is proposing for the
other health hazard sections in appendix A of the HCS. These two
sections correspond to Chapters 3.2 and 3.3 in the GHS. The UNSCEGHS,
in its 16th Session, assembled an informal working group to review the
content of Chapters 3.2 and 3.3 in the GHS, and to propose editorial
revisions in order to enhance clarity and user-friendliness in the
application of the criteria (UN GHS, 2016, Document 0131). The group's
primary focus was to change the order of the text to ensure that the
classification strategy was clear, and to change the testing scheme to
more of an evaluation scheme, since the GHS, like the HCS, is test
method neutral. The work of the informal working group was not complete
before OSHA published its updates to the HCS in 2012. The working group
has since completed its efforts to clarify the skin corrosion/
irritation and serious eye damage/irritation chapters. The work was
approved by the UNSCEGHS in 2012 (UN GHS, 2012, Document ID 0212).
Accordingly, OSHA is now proposing to revise appendices A.2 and A.3 to
incorporate all of the modifications that were made to the GHS skin
corrosion/irritation and serious eye damage/irritation chapters agreed
to by the UNSCEGHS up to and including the GHS Rev. 7. This would
ensure that OSHA remains aligned with the GHS. OSHA is not proposing
any completely new provisions for the HCS; however, OSHA is proposing
to revise the two appendices to align the language and format of the
HCS with the GHS Rev. 7.
    In appendix A.2, skin corrosion/irritation, OSHA proposes to modify
paragraph A.2.1.2 to clarify the sequence in which data should be
evaluated when classifying for skin corrosion/irritation using a tiered
evaluation approach. The proposal would align the language in this
paragraph with the tiered approach in Figure A.2.1. The first tier is
existing human data, followed by existing animal data, followed by in
vitro data, and then other sources of information.
    The proposed changes to the skin corrosion/irritation criteria in
paragraph A.2.2 are mainly editorial in nature. The classification
criteria would remain the same, but the presentation of the information
would be rearranged in a clearer, more logical fashion. In addition,
OSHA is proposing new paragraph A.<IP_ADDRESS>, which is intended to provide
classifiers with factors to be taken into consideration when evaluating
irritant responses.
    The proposed changes in paragraph A.2.3 are also mainly editorial
in nature. The criteria would remain the same, but clarifying text
would be introduced into the section and the criteria would be
presented in a more logical sequence.
    OSHA also proposes to include a new note to Table A.2.3,
``Concentration of ingredients of a mixture classified as skin Category
1 or 2 that would trigger classification of the mixture as hazardous to
skin (Category 1 or 2),'' to indicate how to classify the mixture when
data are available for sub-categorization of Category 1. The proposed
note would align with the note to Table 3.2.3 in the GHS Rev. 7 (UN
GHS, 2017, Document ID 0060; UN GHS, 2012, Document ID 0132), and OSHA
believes that it provides useful information for classifiers.
    Figure A.2.1, ``Tiered evaluation of skin corrosion and irritation
potential'', would remain largely the same under OSHA's proposed
revisions to the appendix. However, OSHA is proposing to revise the
title to ``Tiered evaluation for skin corrosion and irritation.'' OSHA
is also proposing to revise Steps 1a, 1b, and 1c of Figure A.2.1 to
clarify that the parameter being evaluated is existing human or animal
skin corrosion/irritation data. In addition, OSHA is proposing to
modify the finding in Step 4 to clarify that high acid/alkaline reserve
or no data for acid/alkaline reserve should be considered when the pH
is <=2 or >=11.5. OSHA is also proposing some revisions to the
footnotes of Figure A.2.1.
     In proposed footnote (1), OSHA is proposing to revise the
current footnote to include an additional sentence indicating that
although human data from accident or poison center databases can
provide evidence for classification, absence of incidents is not itself
evidence for a not classified determination. In addition, the reference
to evidence from ethically-conducted human clinical studies would be
removed. The text indicating that there is no internationally accepted
test method for human skin irritation testing would also be removed.
     In proposed footnote (3), OSHA is proposing to revise the
existing note to exclude the examples currently provided.
     In proposed footnote (6), OSHA is proposing to revise the
current note to clarify that all available information on a substance
must (instead of should) be considered in making a determination based
on the total weight of evidence. OSHA is also proposing a new sentence
at the end of the footnote to indicate that negative results from
applicable validated skin corrosion/irritation in vitro tests are
considered in the total weight of evidence evaluation.
    In paragraph A.2.4, OSHA is proposing to include in A.<IP_ADDRESS>
language stating that the tiered approach must be taken into account
when evaluating mixtures. In addition, a new paragraph A.<IP_ADDRESS> is
proposed to indicate that when considering testing of mixtures,
classifiers must use the tiered approach to help ensure an accurate
classification, as well as to avoid unnecessary animal testing. This
proposed paragraph also indicates that if there are no other data on
the mixture besides pH, and the pH is extreme (pH <=2 or pH >=11.5),
that information is sufficient to classify the mixture as corrosive to
the skin. However, if the acid/alkaline reserve suggests that the
mixture may not be corrosive despite the extreme pH, then further
evaluation may be necessary.
    In Table A.2.4, ``Concentration of ingredients of a mixture for
which the additivity approach does not apply, that would trigger
classification of the mixture as hazardous to skin,'' OSHA proposes to
delete the phrase ``for which additivity does not apply'' where it
appears in the text of the table in order to reduce redundancy, as that
language is already included in the title of the table. However, OSHA
is proposing to modify the title of Table A.2.4 from ``for which
additivity does not apply'' to ``when additivity does not apply'' to be
consistent with the GHS Rev.7 (UN GHS, 2017, Document ID 0060).
    In appendix A.3, serious eye damage/eye irritation, OSHA proposes
to modify A.3.1.2 to clarify the sequence in which data should be
evaluated when classifying for serious eye damage/eye irritation using
a tiered evaluation approach. The proposal would align the language in
this paragraph with the tiered approach in Figure A.3.1. The first tier
is existing human data, followed by existing animal data, followed by
in vitro data, and then other sources of information.
    The changes OSHA is proposing in paragraphs A.3.2 and A.3.3,
including Tables A.3.1 and A.3.2, are mainly editorial in nature. The
classification criteria in these paragraphs would remain the same, but
the presentation of the information would be rearranged and additional
headings would be included to provide a clearer, more logical sequence.
All of these proposed changes would conform with the GHS Rev. 7 (UN
GHS, 2017, Document ID 0060; UN GHS, 2012, Document 0132).
    Proposed paragraph A.3.2 provides a summary of the classification
criteria for substances that is provided in Tables A.3.1 and A.3.2. In
addition, proposed paragraph A.3.3.6 is a reorganization of existing
paragraphs A.3.3.3 and A.3.3.4.

It would provide guidance on using the tiered approach and making
weight of evidence decisions and also indicates a preference for not
conducting new animal tests.
    Under OSHA's proposed revisions, Figure A.3.1, ``Tiered Evaluation
for serious eye damage and eye irritation'', currently titled
``Evaluation strategy for serious eye damage and eye irritation'',
would remain largely the same. However, as in Figure A.2.1, OSHA is
proposing to revise Steps 1a, 1b, and 1c to clarify that the parameter
being evaluated is existing human or animal serious eye damage/eye
irritation data. In addition, OSHA is proposing to modify the finding
in Step 4 to clarify that high acid/alkaline reserve or no data for
acid/alkaline reserve should be considered when the pH is <=2 or
>=11.5. OSHA is also proposing modifications to the footnotes of Figure
A.3.1 to reflect the most recent test methods.
     In proposed footnote (3), OSHA is proposing to include an
additional sentence that emphasizes that expert judgement should be
exercised when making determinations from existing animal data
indicating serious eye damage/eye irritation, as not all skin irritants
are eye irritants.
     In proposed footnote (4), OSHA is proposing to include
OECD Test Guideline 460 (Fluorescein leakage (FL) as an additional
example of an internationally accepted, scientifically validated test
method for identifying eye corrosives and severe irritants. OSHA is
also proposing an additional sentence for this footnote to indicate
that there are presently no scientifically validated and
internationally accepted in vitro test methods for identifying eye
irritation.
     In proposed footnote (6), OSHA is proposing to revise
existing language to make it clear that all available information on a
substance must (instead of should) be considered in making a
determination based on the total weight of evidence. In addition, OSHA
is proposing to add two new sentences at the end of the footnote to
indicate that the total weight of evidence, including information on
skin irritation, may lead to classification for eye irritation and that
negative results from applicable scientifically validated in vitro
tests are considered in the total weight of evidence evaluation.
    In paragraph A.3.4, OSHA is proposing several minor editorial
changes to ensure consistency in the terminology used. For example,
OSHA is proposing to use the term ``serious eye damage'' (rather than
``eye corrosion'') throughout the text to reflect the name of the
hazard class.
Germ Cell Mutagenicity--(Appendix A.5)
    OSHA is proposing to add a definition for germ cell mutagenicity in
A.5.1.1 explaining that germ cell mutagenicity refers to heritable gene
mutations, including heritable structural and numerical chromosome
aberrations in germ cells occurring after exposure to a substance or
mixture. OSHA is proposing this definition to align with the GHS Rev. 7
(UN GHS, 2017, Document ID 0060; UN GHS, 2016, Document ID 0131).
Because of this new paragraph, the subsequent numbering of existing
paragraphs in A.5.1 would be adjusted accordingly.
    In A.5.4, Examples of scientifically validated test methods,
paragraph A.5.4.2, OSHA proposes to delete the Mouse spot test (OECD
484) as an example of an in vivo somatic cell mutagenicity test, as it
was deleted by the OECD on April 2, 2014. This change is consistent
with the GHS Rev. 7 (UN GHS, 2017, Document ID 0060; UN GHS, 2014,
Document 0087) and ensures that hazard classifications are being
conducted with the most current scientific principles.
Reproductive Toxicity--(Appendix A.7)
    In appendix A.7, Reproductive toxicity, OSHA proposes to revise the
``effects on or via lactation'' hazard category classification criteria
to align with OSHA publication 3844 Hazard Classification Guidance for
Manufacturers, Importers and Employers (OSHA 3844, 2016, Document
0008). During the development of the guidance document, it became
apparent to OSHA that there were issues with regard to the
classification criteria in existing Figure A.7.1(b). The hazard
category for effects on or via lactation captures two separate effects:
    i. Substances that can interfere with lactation; and
    ii. substances and their metabolites that may be transmitted
through breast milk to children in amounts sufficient to cause concern
for the health of the breast feeding child.
    However, the current criteria do not adequately distinguish between
these two separate effects. The first issue has both grammatical and
substantive aspects and is found in the second sentence of Figure
A.7.1(b), which currently reads:
    ``Chemicals that are absorbed by women and have been shown to
interfere with lactation or that may be present (including metabolites)
in breast milk in amounts sufficient to cause concern for the health of
a breastfed child, shall be classified to indicate this property
hazardous to breastfed babies.''
    The italicized phrase is not grammatically correct and is also not
correct as a matter of substance because it ignores the effects on
lactation. As such, OSHA proposes to delete the text to indicate this
property ``hazardous to breastfed babies.'' In addition, the categories
of evidence currently listed in paragraphs (a) through (c) of Figure
A.7.1(b) all provide evidence for effects via lactation rather than
effects on lactation. To be more accurate, and to avoid confusion on
how to apply the criteria for effects on lactation, OSHA proposes to
modify the third sentence in the Figure to read: ``Classification for
effects via lactation shall be assigned on the basis of:'' These
proposed changes would not affect the classification of substances or
mixtures as reproductive toxicants; however, they would be more
accurate and provide more clarity for classifiers.
    OSHA proposes to modify paragraph A.<IP_ADDRESS> to include OECD Test
Guideline 443, Extended One Generation Reproductive Toxicity Study, as
an additional method for one or two generation toxicity testing.
Additionally, in Table A.7.1 ``Cut-off values/concentration limits of
ingredients of a mixture classified as reproductive toxicants or for
effects on or via lactation that trigger classification of the
mixture'', OSHA is proposing a correction to the top left heading from
``ingredients classified as'' to ``ingredient classified as.'' OSHA
believes that the use of the word ``ingredients'' in this context may
be confusing, as it may suggest that the additivity principle should be
applied. Therefore, OSHA is proposing this change for clarity. These
proposed modifications in appendix A.7 are consistent with the GHS Rev.
7 (UN GHS, 2017, Document ID 0060; UN GHS, 2014, Document ID 0221).
Specific Target Organ Toxicity-Single Exposure--(Appendix A.8)
    In appendix A.8, OSHA proposes to make a correction to paragraph
A.8.1.6 to correctly name the hazard class as ``specific target organ
toxicity--single exposure'' instead of ``specific organ systemic
toxicity single exposure.'' Also, in paragraph A.<IP_ADDRESS>.3, OSHA
proposes to delete the erroneous inclusion of the second use of the
word ``evidence'' in the second sentence.
    OSHA proposes to include the concept of ``relevant ingredient''
when classifying mixtures containing Category 3 ingredients using the
additivity approach. Under the HCS, as updated in

2012, the additivity principle was introduced in paragraph A.<IP_ADDRESS>.
However, a ``relevant ingredient'' for this procedure had not been
established. Proposed new paragraph A.<IP_ADDRESS> would provide that in
cases where the additivity approach is used for Category 3 ingredients,
the ``relevant ingredients'' of a mixture are those which are present
in concentrations >=1% (w/w for solids, liquids, dusts, mists, and
vapors and v/v for gases), unless there is a reason to suspect that an
ingredient present at a concentration <1% is still relevant when
classifying the mixture for respiratory tract irritation or narcotic
effects. This proposed paragraph would align with the GHS Rev. 7 (UN
GHS, 2017, Document ID 0060; UN GHS, 2014, Document 0221).
Aspiration Hazard--(Appendix A.10)
    The proposed changes to appendix A.10 would provide clarification
on the classification criteria for mixtures when data are available for
all ingredients or only for some ingredients. OSHA is proposing new
paragraph A.<IP_ADDRESS> to clarify that the concept of ``relevant
ingredient'' applies and that relevant ingredients are those that are
present in concentrations of at least 1%. In addition, a new heading,
``Category 1,'' is proposed as new paragraph A.<IP_ADDRESS>. Proposed
A.<IP_ADDRESS>.1 and A.<IP_ADDRESS>.2 would clarify that the principle of
additivity applies in appendix A.10, but OSHA is not proposing any
substantive changes to the classification criteria. These proposed
changes would align with the GHS Rev. 7 (UN GHS, 2017, Document ID
0060; UN GHS, 2014, Document 0221).
Changes to Definitions and Terminology, Clarification of Mandatory
Requirements, and Corrections
Definitions
    OSHA proposes to update appendix A to include changes to the health
hazard definitions to reflect those adopted by the GHS Rev. 7 (UN GHS,
2017, Document ID 0060; UN GHS, 2016, Document ID 0131). Since OSHA
revised the HCS in 2012, the UNSCEGHS has revised all of the health
hazard definitions in the GHS. These modifications to the health hazard
definitions were incorporated as a result of the work of the UNSCEGHS
Practical Classification Issues working group. The scope of the working
group is to clarify the GHS classification criteria, as appropriate,
and to provide working examples to illustrate application of the
criteria. The previous health hazard definitions were not consistent
with respect to form or content, and many of the definitions were taken
directly from the OECD test guidelines.
    The UNSCEGHS determined that the definitions should be more general
and neutral with respect to test guidelines and that test guideline
criteria should not be part of a definition. The group also determined
that the health hazard definitions should be clear and concise and that
there should be a clear differentiation between ``definitions'' and
``general considerations'' text. OSHA is proposing to adopt all of the
revised health hazard definitions from the GHS Rev. 7 in appendix A, as
well as corresponding changes to text throughout the appendix. For
example, in some cases OSHA is proposing to remove OECD test guidelines
from definitions and to move them to paragraphs outlining
classification criteria. The health hazard definitions that OSHA is
proposing in appendix A are:
     Acute toxicity refers to serious adverse health effects
(i.e., lethality) occurring after a single or short-term oral, dermal,
or inhalation exposure to a substance or mixture.
     Skin corrosion refers to the production of irreversible
damage to the skin; namely, visible necrosis through the epidermis and
into the dermis occurring after exposure to a substance or mixture.
     Skin irritation refers to the production of reversible
damage to the skin occurring after exposure to a substance or mixture.
     Serious eye damage refers to the production of tissue
damage in the eye, or serious physical decay of vision, which is not
fully reversible, occurring after exposure of the eye to a substance or
mixture.
     Eye irritation refers to the production of changes in the
eye, which are fully reversible, occurring after exposure of the eye to
a substance or mixture.
     Respiratory sensitization refers to hypersensitivity of
the airways occurring after inhalation of a substance or mixture.
     Skin sensitization refers to an allergic response
occurring after skin contact with a substance or mixture.
     Germ cell mutagenicity refers to heritable gene mutations,
including heritable structural and numerical chromosome aberrations in
germ cells occurring after exposure to a substance or mixture.
     Carcinogenicity refers to the induction of cancer or an
increase in the incidence of cancer occurring after exposure to a
substance or mixture.
     Reproductive toxicity refers to adverse effects on sexual
function and fertility in adult males and females, as well as
developmental toxicity in the offspring, occurring after exposure to a
substance or mixture.
     Specific target organ toxicity-single exposure (STOT-SE)
refers to specific, non-lethal toxic effects on target organs occurring
after a single exposure to a substance or mixture.
     Specific target organ toxicity-repeated exposure (STOT-RE)
refers to specific toxic effects on target organs occurring after
repeated exposure to a substance or mixture.
     Aspiration hazard refers to severe acute effects such as
chemical pneumonia, pulmonary injury or death occurring after
aspiration of a substance or mixture.
     Aspiration means the entry of a liquid or solid chemical
directly through the oral or nasal cavity, or indirectly from vomiting,
into the trachea and lower respiratory system.
Terminology Issues
    The HCS is currently somewhat inconsistent in the way the terms
``hazard category'' and ``toxicity category'' are used throughout
appendix A. In some cases the terms are used interchangeably, while in
other instances the terms are intended to have different meanings. OSHA
has reviewed appendix A and is proposing revisions to ensure that these
terms are used appropriately and consistently. As such, OSHA proposes
to delete the term ``toxicity category'' and replace it with ``hazard
category'' in various places, including paragraphs A.0.5, A.1, A.8,
A.9, and A.10. These proposed changes would align with the GHS Rev. 7
(UN GHS, 2017, Document ID 0060; UN GHS, 2012, Document 0084).
Mandatory Language
    OSHA is proposing to update a number of provisions in appendix A to
make it clear that those provisions are mandatory. For example, OSHA
proposes to change the term ``should'' to ``must'' in paragraph
A.<IP_ADDRESS>. The change would clarify that the cut-off value/
concentrations in Table A.3.3 are mandatory when determining if a
mixture must be classified as seriously damaging to the eye or an eye
irritant.
Corrections
    OSHA proposes to correct a few errors that currently exist in the
HCS. OSHA erroneously did not include appendix A.4, respiratory or skin
sensitization, in the list of health hazards referenced in the
``concentration of mixtures'' paragraph at A.<IP_ADDRESS>. OSHA proposes

to add a reference to appendix A.4 in paragraph A.<IP_ADDRESS> to clarify
that the concentration of mixtures bridging principle applies to
respiratory and skin sensitization. Similarly, appendix A.4 was also
erroneously excluded from the list of health hazards referenced in the
``interpolation within one toxicity category'' paragraph at A.<IP_ADDRESS>.
Thus, OSHA also proposes to add a reference to appendix A.4 in
paragraph A.<IP_ADDRESS> to clarify that the interpolation bridging
principle applies to respiratory and skin sensitization. In addition,
OSHA proposes to correct the cross-reference from A.<IP_ADDRESS>.3 to
A.<IP_ADDRESS>.4 in Figure A.1.1 and paragraph A.<IP_ADDRESS>.2.

D. Appendix B

    OSHA is proposing a number of changes to appendix B. First, since
the HCS was aligned with the GHS in 2012, new physical hazard classes
or hazard categories have been added to the GHS Rev. 7 (UN GHS, 2017,
Document ID 0060). OSHA proposes to adopt those additions. Second, the
GHS Rev. 7 (UN GHS, 2017, Document ID 0060) contains several updates to
consensus standards and testing methods. Although the HCS does not
require testing and permits classifiers to use data from literature or
experience for classification purposes, OSHA is proposing to update
consensus standards and testing methods referenced in appendix B in
accordance with the GHS Rev. 7 to ensure that data considered for
classification incorporate updated scientific principles. Third, OSHA
is proposing certain corrections and clarifications to appendix B to
address (1) previous inadvertent omissions from the GHS or the HCS; (2)
changes made to the GHS to improve clarity or technical accuracy; and
(3) how some hazard classes should be evaluated in light of the
addition of new hazard classes in the GHS. These proposed changes are
discussed below and would align the HCS with the GHS while improving
the classification and communication of hazards \59\ and maintaining or
enhancing worker safety and health. Additionally, as noted elsewhere,
aligning the HCS with the GHS would ease compliance burdens for U.S.
stakeholders that must also comply with international requirements for
hazard classification and communication.
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    \59\ Specific changes to the hazard and precautionary statements
are discussed below in the section on appendix C.
---------------------------------------------------------------------------

    OSHA is also proposing to make a limited number of changes to
appendix B that arise out of its implementation of the HCS, as updated
in 2012. These changes, explained below, would clarify compliance
requirements. OSHA believes that all of these proposed changes maintain
existing safety and health protections while easing or having no effect
on the compliance burdens for regulated entities.
    Finally, OSHA explains below that it is not proposing to
incorporate one update reflected in the GHS Rev. 7 because that
particular update is inconsistent with the scope of the HCS.
    OSHA is providing a redline strike out version of appendix B, which
reflects all of OSHA's proposed revisions, in the docket and on the
OSHA website (OSHA, 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.
Explosives--(Appendix B.1)
    OSHA is proposing a few minor amendments to appendix B.1,
Explosives. The first change that OSHA is proposing involves a
clarification to the classification criteria for Division 1.6
explosives in B.1.2(f). Under the GHS Rev. 3, one of the criteria for
classification of an article [OSHA uses the term ``item'' in the HCS]
as a Division 1.6 explosive is that it contains ``only'' extremely
insensitive detonating chemicals (UN GHS, 2009, Document ID 0085). The
GHS Rev. 7 (UN GHS, 2017, Document ID 0060) states that the criteria is
met if the article [``item'' in the HCS] ``predominantly'' contains
extremely insensitive detonating chemicals. OSHA is proposing to make
the same change to paragraph B.1.2(f) of appendix B in the HCS.
Changing the criteria from containing ``only'' extremely insensitive
detonating chemicals to ``predominantly'' containing extremely
insensitive detonating chemicals is more technically accurate and
better aligns with the guidance in test series 7 in the UN Manual of
Tests and Criteria (UN TDG, 2016, Document ID 0151). OSHA believes that
consistency in the use of terms will reduce confusion for chemical
manufacturers or importers when classifying explosives.
    OSHA is also proposing to add two notes from the GHS (UN GHS, 2017,
Document ID 0060) to appendix B, paragraph B.1.3.1, that are related to
the addition of the desensitized explosives hazards class (proposed
appendix B.17), which is discussed later in this document. The first
new note OSHA is proposing to add (Note 2) would provide that
explosives for which explosive properties have been suppressed or
reduced must be classified as desensitized explosives. The second new
note OSHA proposes (Note 3) would provide that some chemicals that are
exempt from classification as explosives under UN Recommendations on
the Transport of Dangerous Goods guidelines still have explosive
properties, which must be communicated in section 2 (Hazard
identification) and section 9 (Physical and chemical properties) of the
SDS, as appropriate. The notes would be incorporated in the HCS with
edits to change these provisions from recommendations in the GHS to
requirements in the HCS (e.g., ``may be a candidate for classification
as'' in the GHS would be revised to ``shall be classified as'' in the
HCS) and to revise the GHS terminology to terminology more appropriate
for the HCS (e.g., ``substances and mixtures'' in the GHS would be
revised to. ``chemicals'' in the HCS).
Flammable Gases--(Appendix B.2.)
    OSHA is proposing several changes to the Flammable Gases hazard
class (appendix B.2). Most significantly, OSHA is proposing to
subdivide Category 1 of this class into two subcategories, 1A and 1B,
and to specify that pyrophoric gases and chemically unstable gases are
to be classified as Category 1A. These proposed changes would provide
more detailed information about the flammable gas hazards and track
changes made in the GHS Rev. 7 (UN GHS, 2017, Document ID 0060) since
OSHA updated the HCS in 2012. These proposed changes would allow
downstream users to have a better understanding of the severity of the
hazards associated with flammable gases. Downstream users could then
use this information to take appropriate precautions or determine if a
substitute chemical is less hazardous.
    The HCS currently lists two categories for flammable gases--
Category 1 (Extremely flammable) and Category 2 (flammable)--that are
based on the percentage of the gas in a mixture with air that is
ignitable and on ranges of flammability in air. In practice, with the
current criteria, almost all flammable gases (except ammonia and methyl
bromide, which are treated separately) are classified as Category 1.
This means that, for hazard identification and communication purposes,
no distinctions are being drawn between gases that exhibit a wide
spectrum of flammable properties. OSHA has preliminarily concluded that
Category 1

is too broad and can lead downstream users to choose a chemical without
realizing that an alternative choice is actually less flammable. For
example, 2,3,3,3-Tetrafluoropropene is a non-ozone depleting
refrigerant which ignites less rapidly or violently than some other
flammable gases. Many of these types of gases were developed as a
result of the Montreal and Kyoto protocols, international treaties
intended to phase out gases that are ozone depleting (UN GHS, 2016,
Document ID 0138). However, with the current classification system,
propane, which has a rapid, explosive ignition with a burn velocity of
46 cm/s, and 2,3,3,3-Tetrafluoropropene (R-1234yf), which has a slow,
weak ignition, with a burn velocity of 1.5 cm/s, would both be
classified as Category 1 gases, thus making it appear that the two
gases are equally flammable when in fact 2,3,3,3-Tetrafluoropropene is
considerably less flammable (UN GHS, 2016, Document ID 0138).
    OSHA and DOT actively participated in the UN negotiations (joint
informal working group) in 2015 to ensure that flammable gases are
properly evaluated, classified and communicated. The joint informal
working group activities included identifying, gathering, and reviewing
data on ``less flammable'' gases, including the conduct of numerous
burning velocity tests using approved test methods, as well as tests to
demonstrate ignition behavior, flame propagation, and the speed of the
flame front (UN GHS, 2016, Document ID 0254).
    The revised classification criteria in Table 2.2.1 in Chapter 2.2
of the GHS Rev. 7 (UN GHS, 2017, Document ID 0060) reflect
recommendations made by the joint informal working group. The joint
informal working group agreed that all flammable gases currently
classified as Category 1 flammable gases should remain so. This
decision allows the transport classification and communication scheme
to remain the same. However, the joint informal working group agreed
that Category 1 should be separated into two sub-categories, Category
1A and Category 1B, when data is available on burning velocity and
lower flammability limit. This separation allows for more precise
classification of chemicals and more appropriate communication of the
hazards associated with flammable gases.
    This proposed approach for classifying flammable gases is also
consistent with the approach described in ANSI/ASHRAE Standard 34-
2013--Designation and Safety Classification of Refrigerants (ANSI/
ASHRAE, 2013, Document ID 0160). The ANSI/ASHRAE standard allows
refrigerant gases (which can be category 1A or 1B) to be classified
based on both the lower flammability limit and burning velocity (see
Figure 6.1.4 and Section <IP_ADDRESS>.1 (ANSI/ASHRAE, 2013, Document ID
0160). OSHA's proposed cut-off for the burning velocity for category 1A
and 1B chemicals is the same as that in the ASHRAE standard. Therefore,
the proposed approach is consistent with accepted scientific principles
and industry norms.
    OSHA has preliminary concluded that the classification scheme in
Table 2.2.1 of the GHS Rev. 7 (UN GHS, 2017, Document ID 0060)
maintains safety for workers while allowing for more precise hazard
classification and communication. Therefore, OSHA is proposing to
replace Table B.2.1 of the HCS with the criteria from Table 2.2.1 in