chemical is present in concentrations below the cut-offs. This was
included to ensure that chemicals that can have effects at very low
concentrations, such as sensitizers, will be adequately addressed.
    For physical hazards, the evaluator must determine based on
whatever objective evidence is available whether the hazardous effect
is still possible in smaller concentrations. This recognizes that, for
physical effects, such a determination may be made based on factors
such as dilution, and there are readily available means to make an
appropriate assessment.
    The approach in the current HCS is considered to be a self-
classification system. In other words, the chemical manufacturer or
importer reviews the available information, and makes the determination
as to whether the product presents a potential hazardous effect. This
is different than some other systems where the regulatory authority
makes the determination, and publishes a list of hazardous chemicals
that must be used by the chemical manufacturer or importer.
    The hazard determination is to be completed based on available
information. The current HCS does not require testing of chemicals to
produce information where it is not available.
    The hazard determination approach in the current HCS recognizes
that information about chemicals changes, new chemicals are introduced,
others cease to be used--in other words, the world of chemicals in the
workplace changes constantly, and the standard is designed to ensure
that employees receive the most up-to-date information available
regarding the chemicals to which they are currently being exposed.
    Employers who simply use chemicals, rather than producing or
importing them, are permitted to rely on the information received from
their suppliers. 29 CFR 1910.1200(d)(1). This downstream flow of
information recognizes that the chemical manufacturers and importers
have access to information about the chemicals they sell that is not
available to those who only use them. It also reduces duplication of
effort by focusing the hazard determination process at the source,
rather than having everyone who uses a chemical trying to complete such
a process.
    The current HCS requires chemical manufacturers and importers to
maintain a copy of the procedures they follow to make hazard
determinations. 29 CFR 1910.1200(d)(6). If OSHA finds errors in a label
or SDS, the chemical manufacturer or importer that prepared the
document will be held responsible--not the employer using the chemical.
    The hazard determination procedures in the current HCS, including
the definitions and Appendixes A and B, have been in place since the
standard was promulgated in 1983.
    Hazard classification under the GHS. The challenge in negotiating
an international approach was to create a system that did not require
frequent changes yet remained current and protective, incorporating the
best parts of the approaches in the existing systems. The GHS embodies
an approach that is very similar to the current HCS in scope and
concept, but builds in additional details and parameters to help to
ensure consistency worldwide. Like the HCS, the GHS approach is based
on a downstream flow of information from suppliers to users; self-
classification; use of available information with no new testing; and a
broad approach to definitions of hazard. The GHS has further refined
the approach to include addressing the degree of severity of the
hazardous effects by assigning categories of hazard within hazard
classes; providing detailed scientific approaches to evaluating the
available data to help ensure that multiple evaluators produce similar
results when classifying hazards; and allowing a broader use of
available data by establishing principles where data can be
extrapolated in situations regarding mixtures. OSHA believes that these
additional provisions in the GHS enhance employee protection in
addition to the benefits of having an internationally harmonized
approach when preparing labels and SDSs.
    To accommodate these refinements, and improve protection for
employees exposed to chemicals in the U.S., the final rule modifies the
current HCS as follows. First, paragraph (d) is re-named ``hazard
classification'' rather than the current ``hazard determination.'' This
re-naming is consistent with the approach and terminology used in the
GHS.
    Similarly, final paragraph (d)(1), like the proposal, modifies the
current HCS to indicate that chemical manufacturers and importers are
required to classify the chemicals' health and physical hazards in
accordance with this section. For each chemical, the chemical
manufacturer or importer must determine the hazard classes, and the
category of each class, that apply to the chemical being classified.
    Final paragraph (d)(1) allows employers to rely on information
received from suppliers (i.e., chemical manufacturers or importers). In
the final rule, OSHA made two minor changes to the proposed text.
Instead of saying that chemical manufacturers would be required to
classify ``their'' physical and health hazards, OSHA has replaced
``their'' with ``the chemicals'' for clarification purposes. In
addition, OSHA has added the phrase ``where appropriate'' to add
clarity that not all hazard classes have more than one category. The
final paragraph (d)(1) now reads as set forth in the regulatory text of
this final rule.
    Final paragraph (d)(2), which is identical to the proposal,
similarly modifies the current HCS's terminology regarding
classification. However, the final paragraph also includes
modifications to address the evaluation process and the role of
testing. The paragraph specifically states that evaluation of the
hazards of chemicals requires the evaluator to ``identify and consider
the full range of available scientific literature and other evidence
concerning the potential hazards.'' This is consistent with the current
HCS, but re-emphasizes the responsibility to fully characterize the
hazard of the chemicals. To clarify that available evidence is to be
used, final paragraph (d)(2) specifically states that there is no
requirement to test a chemical to classify its hazards under the
modified provisions--just as there is no such requirement under the
current HCS. Dow Chemical Company (Document ID 0353) suggested
that OSHA revert to the current text of paragraph (d)(2), which simply
referred to Appendix B for the parameters of the hazard determination.
This would not be appropriate since Appendix B no longer exists in its
current form. But OSHA does not believe that what is written in
paragraph (d)(2) is inconsistent with what is currently required in
Appendix B. It is not intended to mean (and does not say) that an
evaluator must identify every ``shred'' of information as Dow has
indicated in its comment, but rather that the evaluator cannot, for
example, only review acute toxicity data and consider that a complete
evaluation. The extent of the literature search must be what the
reasonably prudent classifier would do to assure themselves that
evidence for the range of hazards covered by the rule has been
identified, and a thorough evaluation has been done of the potential
effects. That is

what is required today under the current HCS.
    On the other hand, the Styrene Information and Research Center
(SIRC) (Document ID 0361) commented on the same paragraph as
follows:

    SIRC supports hazard classification for carcinogenicity and
other endpoints based on a comprehensive assessment of the ``full
range of available scientific literature and other evidence
concerning the potential hazards,'' within a best available science
framework. This approach should provide optimum precision assessing
potential hazards and a sound basis for maintaining a safe and
healthy workplace.

    Final paragraph (d)(2) refers to Appendixes A and B for further
information on classification as in the current standard. However, the
Appendixes have been completely changed from the current text. New
Appendix A includes the criteria for classification of health hazards,
and new Appendix B includes the criteria for classification of physical
hazards. These mandatory appendixes have to be used for the hazard
classification process under the revised standard. The Appendixes have
been adopted in the final rule, with some changes as described below.
    Reference to these appendixes is also included in final paragraph
(d)(3), which addresses mixtures. Final paragraph (d)(3)(i), like the
proposal, states that chemical manufacturers and importers must follow
the procedures in Appendixes A and B to classify hazards for mixtures
as well as for individual chemicals. Proposed paragraph (d)(3)(ii)
stated that the chemical manufacturer or importer ``shall be
responsible for the accuracy of the classification even when relying on
the classifications for individual ingredients received from the
ingredient manufacturers or importers on the safety data sheets.'' SIRC
expressed reservations about this proposed paragraph (Document ID
0494 Tr. 128-29; See also Document ID 0361). In
commenting on this provision, SIRC said it was uncertain whether this
provision meant that a classifier could rely on the classifications
found in SDSs from the ingredient supplier, or whether the classifier
was required to ensure that the supplier's classification was correct.
It was OSHA's intent in the proposal to clarify that generally
classifiers may rely on the classifications found on the SDSs received
from suppliers. The final rule revises (d)(3)(ii) to state that when
chemical manufacturers and importers are classifying mixtures, they may
rely on the information provided on current safety data sheets of the
individual ingredients, except where the chemical manufacturer or
importer knows, or in the exercise of reasonable diligence should know,
that the safety data sheet misstates or omits required information.
    In reconsidering the language proposed, OSHA wanted to ensure that
chemical manufacturers and importers know that, in most cases, they can
continue to rely on their suppliers' SDS information for ingredients
they will be using in formulations. However, where they know
information is incomplete or wrong, they have some responsibility for
ensuring they have the correct information before using it for their
own evaluations.
    During implementation of the current HCS, OSHA allowed formulators
of chemicals to develop an SDS by simply providing the SDSs for all the
ingredients rather than compiling a specific SDS for the product. OSHA
does not believe that this practice of providing the SDSs for all the
ingredients is widely pursued, but it will not be permitted under the
final rule. The revisions to the approach to classifying mixtures do
not lend themselves to such a practice. Hazard classification requires
consideration and application of bridging principles based on the
constituents, as well as the application of a formula when there are
multiple ingredients with acute toxicity. These approaches require the
evaluator to determine a classification for the mixture as a whole. In
addition, this practice places more of a burden on the user of the
product to sort out the relevant information for protection of their
employees. The formulator is in a better position to assess the
information and provide what is needed to their customers.
    Under the current HCS, paragraph (d)(6) requires chemical
manufacturers, importers, or employers performing hazard determinations
to keep a copy of the procedures they follow in the hazard
determination process. This provision has been deleted in the final
rule because the hazard classification procedures have been specified,
and thus all evaluators are following the same process.
    Final paragraph (d) is thus much shorter and less detailed than
paragraph (d) in the existing standard. This is largely due to the
approach in the GHS to include the details regarding classification in
hazard-specific discussions that address both the individual substance
and that substance in mixtures. Given the volume of these criteria, it
appeared to OSHA that presenting the relevant information in mandatory
appendixes was a more efficient way to describe the criteria than
including it all in the primary text of the standard. This is
particularly true for those many employers reading the standard who do
not have to perform hazard classification--the revisions only apply to
chemical manufacturers and importers, unless an employer chooses not to
rely on information received from them.
    The GHS criteria. A number of commenters expressed their general
support for the GHS criteria, and agreed that the criteria will result
in thorough, harmonized hazard evaluations (See, e.g., Document ID
0329, 0330, 0335, 0339, 0370, 0375, and 0389). In adopting the
GHS approach, the final rule deletes from the hazard classification
requirements the ``floor'' of hazardous chemicals described above--
established lists of chemicals that are considered hazardous under the
HCS in all situations. In addition, OSHA deleted the across-the-board
``one study'' rule described above, wherein one good scientific study
established that a substance is a hazard. However, the one-study
approach is still included in some of the criteria in the GHS, and thus
in the revised OSHA rule.
    With the detailed criteria, and the weight of evidence approach in
the GHS, OSHA indicated in the NPRM that it appeared to no longer be
necessary to have such a floor or the one study rule. Many commenters
agreed with OSHA (See, e.g., Document ID 0313, 0327, 0328,
0336, 0338, 0339, 0344, 0351, 0361, 0363, 0365, 0367, 0370, 0371, 0375,
0376, 0377, 0379, 0381, 0382, 0383, 0393, 0399, 0405, 0408, and 0410).
For example, the Alliance of Hazardous Materials Professionals
(Document ID 0327) indicated:

    Elimination of the ``floor'' definition of hazardous (as
consistent with the GHS) would require producers and users to more
closely examine the properties of the materials they produce or
handle. While this would increase the effort necessary to determine
that some substances are hazardous, it would also force a more
careful examination of the underlying reasons that the substance is
hazardous.

    There were few comments that questioned taking the floor out of the
requirements given the detailed nature of the criteria to evaluate
hazards. It was noted that the lack of a floor may result in some
inconsistencies in evaluations (Document ID 0352). There were
also some concerns about removing IARC and NTP as sources to evaluate
chemicals (Document ID 0321). Conversely, others supported
elimination of these resources because inclusion violated the Data
Quality Act (Document ID 0417)--a conclusion that OSHA does
not believe is accurate. Evaluation of carcinogens will be

addressed further below. OSHA has not included a ``floor'' of hazardous
chemicals in the final standard.
    As OSHA indicated in the proposed rule (74 FR 50282, Sept. 30,
2009), the Agency planned to adopt all of the health and physical
hazard classes in the GHS, but not all of the hazard categories. In
keeping with its intent to maintain the scope of coverage of the
existing rule to the extent possible, as well as to be as consistent as
possible with the scope of the European implementation of the GHS, OSHA
did not propose to adopt Acute Toxicity, Category 5; Skin Corrosion/
Irritation, Category 3; and Aspiration Hazard, Category 2.
    Many commenters agreed that the categories selected in the proposal
were appropriate (See, e.g., Document ID 0313, 0327, 0329,
0330, 0338, 0344, 0351, 0353, 0365, 0367, 0370, 0376, 0377, 0379, 0381,
0382, 0383, 0393, 0399, 0402, 0408, and 0410), although there were some
who thought all hazard categories should be adopted to be completely
consistent with the GHS (See, e.g., Document ID 0328, 0335,
0336, and 0339). There were other comments that supported streamlining
the document by omitting the guidance portions of the GHS (Document ID
0328, 0399, and 0408); stated that the goal should be
harmonization with trading partners, so if they exclude categories,
OSHA should exclude them too (Document ID 0335 and 0389); or
indicated that OSHA should accept labels and SDSs that include the
excluded hazard categories (Document ID 0328, 0379, and 0405).
OSHA indicated in the NPRM (74 FR 50383, Sept. 30, 2009) that
additional information could be included on labels and SDSs in any
event, and that is the position in the final rule as well. (See (g)(2);
Appendix C.3.)
    While the decision logics for the health and physical hazard
criteria were omitted from the regulatory text, OSHA indicated that it
would consider publishing them as guidance. Commenters agreed with this
concept (See, e.g., Document ID 0344, 0351, 0370, 0381, 0410,
and 0453). It was further suggested that the diagrams be made simple so
all workers can understand them (Document ID 0336). The
decision logics are already part of the GHS, and are graphic
representations of the process of determining each type of hazard. As
such, they are tools for preparers of labels and SDSs, rather than for
exposed workers. Another comment was that public comment should be
sought on the decision logics before publishing them (Document ID
0379). Given that they are already part of the agreed text of
the GHS, and are guidance, OSHA will make them readily available on the
Agency's Web page.
    There were also comments that OSHA should publish guidance on its
interpretation of criteria application, and indicate whether it agrees
or disagrees with interpretations published by other countries
(Document ID 0382). OSHA is considering many different types
of guidance documents, but has not made final decisions in this regard.
Background on Appendices A and B
    The text of Appendixes A and B is the bulk of what was proposed to
be adopted essentially verbatim from the GHS. While some of the
provisions of the GHS have been adopted into the final rule with OSHA-
developed language that is specific to the regulatory system of the
U.S., OSHA has strived in these appendixes to retain the text of the
GHS intact. In order to understand the context of this language, and
OSHA's approach to its inclusion, a brief history of its development is
necessary.
    Most people think of the labels and SDSs as the products of the GHS
that are harmonized since they are the system's ``output'' that are
seen most frequently. But harmonization of these documents cannot occur
unless the underlying criteria are harmonized, and countries adopting
them implement them similarly. The health hazard criteria were
developed in the Organization for Economic Cooperation and Development
(OECD)--an organization of 34 countries that ``provides a forum in
which governments can work together to share experiences and seek
solutions to common problems.'' See www.oecd.org. One of the areas in
which the OECD has long been actively involved is chemicals. As such,
the OECD provides a forum for countries' experts to discuss and resolve
issues of mutual concern. In addition, the OECD works with business,
through the Business and Industry Advisory Committee, and with labor,
through the Trade Union Advisory Committee. Perhaps its most visible
contribution in the area of chemicals is test guidelines to assess the
hazards of chemicals. These test guidelines address many different
health effects; are considered to be scientifically robust, validated
test methods; and are widely used around the world.
    It was this expertise and recognition that led to the OECD being
the ``focal point'' for development of the health hazard criteria. The
OECD also uses a process of consensus to develop their documents,
requiring agreement from all countries to move forward rather than a
simple majority vote. Working on a consensus basis is much more
difficult to accomplish, but is advantageous in other ways since it
helps to ensure that the concerns of all parties are taken into
consideration, and thus are more likely to remain consistent with the
results.
    A disadvantage is that the text must satisfy all parties, and thus
it is not always written in the clearest fashion. The text was also
reviewed further when it was submitted to the UN Sub-committee, and
additional editing was done to address concerns. Therefore, it is fair
to say that it was written by expert committees, and reflects the
involvement of many different people and ideas.
    The criteria in Appendix B, unlike those in Appendix A, were not
developed ``from scratch,'' but were based on the harmonized criteria
developed to classify the physical hazards of chemicals involved in
transport by the UN Sub-committee of Experts on the Transport of
Dangerous Goods (TDG). The TDG Sub-committee includes many subject
experts in areas such as explosives and flammability. The TDG Sub-
committee and the International Labor Organization (ILO) were jointly
tasked to review the TDG criteria for application to other sectors such
as the workplace. This review not only took advantage of the UN and ILO
expertise, but also created a system that is harmonized with transport
in terms of criteria.
    When OSHA developed the proposed rule, it considered editing the
text of the criteria for purposes of improving the language. However,
the trade-off is inconsistency with the GHS, and the potential for
people to believe that OSHA means something different because the text
has been revised. Thus, as noted in the NPRM (74 FR 50392, Sept. 30,
2009), OSHA chose to take the approach of adopting the language as
stated in the GHS. Editing of the criteria focused on what needed to be
changed for purposes of putting it into mandatory regulatory language,
including deleting what was clearly identified as guidance.
    Therefore, while we have reviewed every suggestion that was made to
the text of the Appendixes, our general approach was not to make
changes unless they were truly necessary. Editorial changes for
purposes of clarification are more appropriately made through the UN
Sub-committee process, and OSHA participates actively in that activity,
and chairs the primary correspondence group. Those changes that were
suggested that OSHA believes have merit in terms of clarifying

provisions will be worked through this correspondence group so the UN
Sub-committee can make the changes. Then OSHA will adopt them into the
revised standard through rulemaking processes discussed elsewhere in
this preamble. To avoid giving this same response repeatedly, OSHA will
not be individually addressing the many suggestions for clarifications
in this preamble.
    In general, there were very few substantive technical comments
provided on the approaches in the criteria, and OSHA assumes that
reflects the fact that the criteria were developed by technical experts
from countries and stakeholder organizations. There were some
suggestions received that certain parts of Appendix A be withdrawn so
OSHA can consult with toxicologists (Document ID 0353).
Numerous toxicologists and other health professionals from the U.S., as
well as many other countries, have been involved in the development and
review of the text in Appendix A, and it has been subject to extensive
scientific and policy discourse. Furthermore, this rulemaking was also
the opportunity for others who have not been involved to provide input.
If OSHA had received significant comments on the technical aspects of
the criteria that indicated a systemic concern about the criteria, it
may have been cause for reconsideration. But most of the comments that
were received were more reflective of differences on policy positions
than truly technical issues. Therefore, there are relatively few
changes to Appendixes A and B as a result of record input. These
changes are discussed below.
    As described in the NPRM and this document, in Appendixes A and B
OSHA has maintained its general approach (supported by stakeholders)
of: (a) Limiting changes to the HCS to those that are required to align
with the GHS; and (b) remaining as consistent with the GHS as possible
within the need to use appropriate regulatory language and maintain or
enhance current protections. OSHA has also remained mindful of the
approaches of its trading partners, although it notes that some
proponents of that principle were quite inconsistent themselves when
using this particular argument. Therefore, while this argument was used
to support choosing higher cut-offs for mixtures, for example, some of
these same commenters also suggested not covering hazard classes or
categories that are both covered by the EU and currently addressed by
OSHA (See, e.g., Document ID 0344, 0381, and 0393). These
comments are addressed below.
    Appendix A, Health Hazards. Proposed Appendix A began with an
introduction that includes material related to principles of
classification taken from Chapter 1 of the GHS. These address both
weight of the evidence, and the approach to mixtures. In A.0.3.2, the
proposed text referred to both positive and negative results being
``assembled together.'' Dow (Document ID 0353) expressed
concern about the implications of the word ``assembled.'' In the final
rule, OSHA has revised this language throughout the chapter to say
``shall be considered together.'' Dow also commented that in the
discussion regarding acceptable data in A.0.2.2 and A.0.2.3, the text
should refer to ``valid'' methods, rather than ``validated.'' OSHA does
not agree that this change is warranted. To be ``valid'' data, the
methods used to produce the data must be validated. In order to clarify
the discussion, OSHA has revised the text by adding two sentences from
the GHS to A.0.2.3 as follows:

    Any test that determines hazardous properties, which is
conducted according to recognized scientific principles, can be used
for purposes of a hazard determination for health hazards. Test
conditions need to be standardized so that the results are
reproducible with a given substance, and the standardized test
yields `valid' data for defining the hazard class of concern.

    As mentioned below in the discussion on mixtures, OSHA has also
revised Appendix A to use ``cut-offs/concentration limits'' everywhere
one of these terms was formerly used in order to be consistent, and
make clear the terms are interchangeable.
    The remainder of Appendix A is taken from Chapter 3 of the GHS on
Health Hazards. OSHA has included the specific discussions of all of
the health hazards covered by the HCS in proposed Appendix A, extracted
from Chapter 3 of the GHS. OSHA removed the decision logics that are in
the GHS from the criteria, and is considering including them in a
guidance document to be made available at the time the final rule is
published. As discussed above, stakeholders generally supported this
approach. The hazard communication portions of the criteria chapters
have also been removed since all of this information is already
available in Appendix C and would thus be duplicative. In addition,
edits have been made where OSHA is not adopting all of the categories
of a particular hazard class.
    The chapters on Skin Corrosion/Irritation (Chapter A.2) and Serious
Eye Damage/Irritation (Chapter A.3) have been modified more extensively
than the other chapters on health hazards in the GHS. In these
chapters, the GHS leads the evaluator to conduct additional testing on
the chemical when information is not available. While the GHS does not
require such testing, the criteria for these effects imply that it
should be conducted to complete an evaluation. The HCS is based solely
on available information, and no testing is ever required. Therefore,
OSHA has modified these chapters to eliminate any references to
additional testing and limit the evaluation to what is known based on
available information. It should be noted that the UNSCEGHS has
initiated work to edit these chapters and make them easier to follow.
OSHA will continue to participate in this activity.
Coverage of Mixtures
    The coverage of mixtures in terms of health hazards is addressed in
two places in the revised rule. First, general principles that apply to
multiple effects are addressed in the introductory part of Appendix A
in Chapter A.0, ``General Classification Considerations.'' Second, each
hazard class discussion includes the criteria for classifying a
substance or a mixture. Unlike the current HCS, which defines across-
the-board percentage cut-offs for all health hazard classes, the GHS
employs a tiered approach to classification. Like the HCS,
classification would be based on test data for a mixture as a whole for
most hazard classes where it is available. However, where it is not
available, but there are data on ingredients and similar mixtures, the
GHS allows extrapolation or bridging of data to classify a mixture.
This allows greater use of available data before resorting to a
percentage cut-off or similar approach. Where such data are not
available, the criteria address how to classify mixtures based on cut-
offs specific to that hazard. In the case of acute toxicity, this
includes calculations based on the acute toxicity of each ingredient in
the mixture.
    The tiered scheme is somewhat different for certain hazard classes.
As described, usually the evaluation is based first on test data
available on the complete mixture, followed by the applicable bridging
principles and, lastly, cut-offs/concentration limits or additivity.
The criteria for Germ Cell Mutagenicity, Carcinogenicity, and
Reproductive Toxicity take a different approach by considering the cut-
off levels as the primary tier and allowing the classification to be
modified on a case-by-case basis based on available test data for the
mixture as a whole. This approach is related to the sensitivity of
available test methods to detect these types of effects at small

concentrations in the mixture as a whole.
    The approach to mixture classification may result in some mixtures
that are currently considered to pose a particular hazard not being so
classified under the GHS. OSHA believes that the protections of the GHS
approach are appropriate, and that these changes will not result in an
inappropriate reduction in protection. For example, if there is a
mixture that is comprised of 1% of an acutely toxic material,
regardless of the severity of that effect, and 99% water, the current
HCS would require that mixture to be considered acutely toxic. Under
the GHS, it is unlikely to be considered as such. Based on the dilution
effect of the water, the acute toxicity is no longer a concern. Thus
the bridging principles under the GHS allow for a more accurate
assessment of the potential harm of the mixture, whereas the strict
cut-off approach under the current HCS may provide hazard information
in cases where the exposure is minimal and the occurrence of an adverse
effect is unlikely. In the example described, the presence of the water
in the mixture as used by the workers reduces the potential for
exposure to the hazardous ingredient to such a small amount that no
effect is expected to result. The GHS approach is not as simple to
apply as the current HCS, but the resulting approximation of the
hazards of the mixture will be more accurate.
    The GHS uses both the term ``cut-off'' (which is what is used in
the current HCS), and ``concentration limit'' (which is used in the EU
requirements). The terms are used interchangeably and often appear
together (i.e., cut-offs/concentration limits). Several commenters
indicated that OSHA should define these terms (Document ID
0344, 0381, and 0393). There are no definitions in the GHS
since the terms are self-evident when viewed in the context of how they
are used. OSHA does not believe that definitions are needed for these
terms. However, Appendix A has been reviewed to make sure the terms are
both used consistently throughout the Appendix. The GHS was also
reviewed, and it appears the terms are not necessarily used
consistently in that text.
    Several commenters indicated that language in A.<IP_ADDRESS>(a), in the
bridging principle that addresses dilution, was inappropriately changed
from ``may'' to ``shall'' in the NPRM (See, e.g., Document ID
0344, 0381, 0382, and 0393). OSHA changed the language to
track the mandatory nature of the provision when present in a standard
versus a non-mandatory recommendation such as the GHS. Therefore, the
language remains as ``shall'' in the final rule.
    In another part of the bridging principles, the term ``commercial
product'' is used in the GHS, and was thus used by OSHA in the NPRM
(A.<IP_ADDRESS>). Commenters asked that this term be defined (Document ID
0344 and 0381). OSHA reviewed the text, and has changed the
term to ``mixture'' instead of ``commercial product''. This is
accurate, and the term is already defined.
    There are several hazard classes in the GHS that give competent
authorities such as OSHA a choice of cut-offs/concentration limits to
apply when classifying a mixture containing ingredients that pose these
effects (e.g., reproductive toxicity, sensitization, target organ
effects). The reason the GHS includes a choice of cut-offs to trigger
label disclosure is that countries involved in the negotiations on
mixtures had different views on the issue that could not be resolved.
All countries agreed to use the lower of the two cut-offs for SDSs, so
information will be provided consistently for those documents in all
cases. But for labels, some countries had what were described as
``downstream consequences'' that were linked to label disclosures, and
therefore did not want to adopt the lower level and trigger those
consequences (e.g., banning the use of the chemical for consumer
products).
    In North America, Canada and the U.S. do not have such consequences
linked to label statements, and their requirements are based on giving
workers the right-to-know about the hazards and identities of the
chemicals in their workplaces. Additionally, Canada has the lower cut-
offs in most cases in their current requirements, and OSHA already has
the 0.1% cut-off for carcinogenicity. Adoption of the lower cut-offs
for both labels and SDSs was supported by both Canada and the U.S. from
the outset.
    As has been described, OSHA has used consistent cut-offs for
purposes of hazard determination for mixtures since the HCS was
promulgated in 1983. OSHA described the proposal as follows in the 1983
final rule preamble (48 FR 53290, Nov. 25, 1983):

    The rationale of the proposal was that when the hazard of a
mixture is unknown, all hazardous ingredients should be indicated on
the material safety data sheet. The user would then have the most
complete information available to predict the potential hazards of
the mixture. The one percent exclusion was included to absolve the
employer from having to evaluate and list chemicals in small
quantities, which are not likely to result in substantial exposures.

    In the 1982 proposal, the one percent cut-off would have applied to
all health and physical hazards. As a result of the comments submitted
to the record, OSHA took a different approach to physical hazards in
the final rule (no percentage cut-off applies to physical hazards), and
also lowered the cut-off for carcinogenicity to 0.1 percent. In
addition, a provision that required inclusion of chemicals below these
cut-offs in certain situations was also part of the 1983 final rule.
    In proposing the one percent cut-off, OSHA noted that ``there was
no scientifically correct delineation, but that the one percent cut-off
is apparently considered reasonable by a number of parties'' (47 FR
12102, Mar. 19, 1982). OSHA's intent was ``to absolve the employer from
having to evaluate and list chemicals present in mixtures in small
quantities, which are not likely to result in substantial exposures''
(48 FR 53290, Nov. 25, 1983). These cut-offs were practical
accommodations, had been used in other regulatory settings (See, e.g.,
29 CFR 1910.1003(a)(2), 13 Carcinogens), and in the 1983 final rule
were accompanied by a provision that also covered those situations
where the cut-offs were too high for protection purposes. Science
regarding potential health hazards in the workplace does not provide
evidence that would allow the Agency to draw a bright line to indicate
specific concentrations of a chemical in a mixture are, or are not, a
potential hazard to workers. Therefore, the establishment of such cut-
off levels is a policy decision based on scientific considerations, as
well as concerns regarding practicality and utility, but not on studies
that can be linked to a particular level for each type of health
effect.
    That being said, however, the scientific knowledge about these
health effects has increased significantly since the HCS was first
adopted, as has the concern about their occurrence in the work force.
At that time, carcinogenicity was the primary concern in terms of
chronic and/or significant health effects, and this concern was
reflected in the lower cut-off value adopted by OSHA for that effect.
Most of OSHA's substance-specific rulemakings were done for the purpose
of addressing carcinogenicity. Now, however, there is more evidence
that raises significant concerns about other types of effects.
    Sensitization is a key example. Respiratory sensitization leads to
asthma, and substantial evidence has

developed over the last few decades showing this effect is of
increasing concern. For example, a study by Frazier et al. (2001,
Document ID 0587) notes that the incidence of occupational
asthma has increased by 50% over the last two decades, and that
population-based surveys have reported that 5% to 21% of asthma cases
are caused or exacerbated by occupational exposure. The authors
extrapolated this to the estimated 12 million adults who have asthma in
the U.S., and concluded that this suggested that between 500,000 and
2.5 million Americans had occupational asthma. This study was published
in 2001, and the numbers are likely to be larger today. The study also
examined SDSs for chemicals containing toluene diisocyanate, a known
respiratory sensitizer, and found only half the SDSs noted asthma as a
potential health effect, and one in four noted neither asthma nor
respiratory sensitization effects. Other studies have also examined the
increasing concerns about occupational asthma (Document ID
0588, 0591, 0592, and 0593).
    Further, the most recent science shows that respiratory and skin
sensitization can be caused at very low concentrations. A 2006 paper by
Arts et al. summarizes human and animal studies on skin and respiratory
sensitizers, and finds that sensitization effects often result from
exposures to chemicals at concentrations below 1% in studied
populations (Document ID 0593). Likewise, the World Health
Organization's report, ``Skin Sensitization in Chemical Risk
Assessment,'' also reports positive results for skin sensitization well
below the 1% cut-off used by the current HCS (Document ID
0586). Moreover, once an individual is sensitized, a response
can be triggered at even lower levels than those required initially to
induce sensitization (Document ID 0585 and 0593). OSHA has
often used sensitizers as an example of why SDS preparers need to
consider whether information should be provided below the 1% cut-off.
For example, in OSHA's compliance directive for the HCS (CPL 02-02-
038), the following guidance is given:

    If the components of a mixture could be released in
concentrations which would exceed an OSHA PEL, an ACGIH TLV, or
could present a health risk to employees, information on these
components must be included on the MSDS regardless if their final
concentration in the mixture is less than 1% (or 0.1% for
carcinogens). For instance, TDI is a sensitizer at very small
concentrations and despite its low concentration in a mixture, can
be offgassed in quantities which may present a health risk that must
be noted on the MSDS.

    But sensitization is not the only effect of concern. Reproductive
toxicity is a serious hazard that includes both fertility and effects
on the offspring. Recent research concerning endocrine disruptors
suggests that these chemicals can have adverse reproductive effects at
very low levels (Document ID 0583, 0584, and 626). Likewise,
occupational disease mortality and morbidity statistics indicate a
number of cases related to target organ effects as well (Document ID
0291, e.g., heart disease and renal effects).
    OSHA proposed to use the most protective of the GHS concentration
limits for these hazard classes. For sensitizers and reproductive
toxins, the final rule requires information to be provided on labels
and safety data sheets at concentrations above 0.1%. Other countries
may choose to only provide the information on SDSs when the
concentration is higher. However, as indicated, these particular health
effects are among the most significant to employees, and OSHA believes
the provision of information on labels will help both employers and
employees ensure that appropriate protective measures are followed. (On
the other hand, it should be noted that OSHA was persuaded that the
current 1% cut-off may be too conservative for many acute toxins and
Category 3 Single Target Organ Toxicants, and the final rule is likely
to result in fewer mixtures being covered for these effects than under
the current approach.)
    In addition to concerns regarding protection for these health
effects, there is also a concern about the communication difficulties
of having different hazard information on a label versus a safety data
sheet. As indicated, the GHS negotiators agreed that all countries
would use the lower levels in the criteria for providing information on
SDSs. Using a different cut-off for labels would create a situation
where there may be hazards on the SDS that do not appear on a label.
This inconsistency makes training more difficult, and creates confusion
for downstream employers as well when they are deciding about
appropriate protective measures. Under the current rule, the mixture
cut-offs apply to both the label and the SDS. Several commenters
indicated that OSHA should provide guidance indicating specific
threshold cut-offs (Document ID 0344, 0381, and 0399). The
table below indicates what the cut-offs are for different health
hazards. These commenters also suggested OSHA provide guidance on
opting out of the cut-offs if data override the threshold. This is
already addressed in A.<IP_ADDRESS> (if the classifier has information that
the hazard of an ingredient will be evident (i.e., it presents a health
risk) below the specified cut-off/concentration limit, the mixture
containing that ingredient shall be classified accordingly). A.<IP_ADDRESS>
also allows the cut-off/concentration limit to be higher in exceptional
cases. The evaluator must have conclusive data demonstrating that the
hazard of an ingredient will not present a health risk. OSHA
anticipates that the criteria of A.<IP_ADDRESS> would rarely permit this
approach to be used.

                              Table XIII-1
------------------------------------------------------------------------
           Hazard class               Label cut-offs      SDS cut-offs
------------------------------------------------------------------------
Respiratory/Skin sensitization....             >=0.1%             >=0.1%
Germ cell mutagenicity (Category               >=0.1%             >=0.1%
 1)...............................
Germ cell mutagenicity (Category               >=1.0%             >=1.0%
 2)...............................
Carcinogenicity...................             >=0.1%             >=0.1%
Reproductive toxicity.............             >=0.1%             >=0.1%
Specific target organ toxicity                 >=1.0%             >=1.0%
 (single exposure)................
Specific target organ toxicity                 >=1.0%             >=1.0%
 (repeated exposure)..............
Specific target organ toxicity                   >20%               >20%
 Category 3.......................
------------------------------------------------------------------------

    During the hearing, worker representatives were asked to comment on
whether consistency between the information on the label and the SDS
was important for worker protection. They all indicated that it was
important. For example, Mr. Platner, who represented the Building and
Construction Trades Department of the

AFL-CIO stated (Document ID 0494 Tr. 25):

    Oh, absolutely. An example of a sensitizer that's very common is
isocyanate components or polyurethane spray foams or coatings.
They're potent sensitizers, and that information very rarely gets to
the label. It's usually appropriately in the MSDS, but it rarely
makes it to the label.

    Similarly, Mr. Kojola of the AFL-CIO, commented (Document ID
0494 Tr. 33):

    Oh, absolutely. What it does is it provides a consistent message
that workers are getting both in labels and on safety data sheets.
And I think it enhanced the ability to, for example, translate that
information into other languages, so I think that alone is a major
step forward in enhancing worker protection.

    Some commenters argued that OSHA should adopt the higher cut-off
levels where given a choice by the GHS (Document ID 0344,
0361, 0367, 0371, 0376, 0381, 0392, and 0393). They questioned whether
there was a scientific justification for the lower levels, and
suggested that the U.S. should harmonize with the EU approach.
    As OSHA described above, there are two primary reasons for the
lower levels. First, OSHA believes it is important for effective
communication to have the same hazards on the label and SDS to as great
a degree as possible. Labels are in an employee's work area, and thus
provide the most immediate source of information. While SDSs must be
available, they are longer and more complicated, and workers are less
likely to review them on a regular basis. For downstream employers, it
is also important to maintain consistency and reduce confusion where
possible by having the information on hazards the same on the label and
SDS.
    Secondly, as discussed above, increased knowledge of these health
effects in the scientific literature, as well as studies indicating
that they are often not reported when they should be, or the
information is lacking, has led OSHA to the conclusion that
communication at the lower levels is appropriate and necessary for
worker protection. It is particularly critical in the area of
sensitizers since the incidence of occupational asthma is increasing,
and sensitization can occur at lower levels as it progresses. But with
the advent of information on effects like those of endocrine
disruptors, and the increased awareness of the possible effects of low
levels of exposure, it is necessary for all of these effects.
    As for the argument regarding consistency with the EU, OSHA has
sought to be consistent where possible. However, the EU has a different
regulatory structure for dealing with these effects downstream, and
what is appropriate for their classification and labeling system is not
necessarily appropriate for ours in the U.S. (See, e.g., http://ec.europa.eu/environment/chemicals/dansub/pdfs/30_atp.pdf: ``Under
Directive 76/769/EEC on the restrictions of certain dangerous
substances and preparations, the Commission is, in principle, obliged
(within six months of the publication of the classification) to propose
a ban on their placing on the market and use by consumers as substances
or in preparations (above specified concentrations).'')
    There are relatively few chemicals for which there are data
indicating the types of effects of concern with regard to these lower
cut-offs (e.g., sensitizers), and fewer still that would fall into the
range between the lower and higher cut-offs (e.g., between 0.1% and
0.3% for reproductive toxicity). Furthermore, as suggested in one
comment, disclosing at different levels on labels versus SDSs may
actually create a product liability issue under U.S. law that would
argue against taking such an approach (Document ID  0353).
While product liability is not one of the issues that influenced OSHA's
decision-making, it may be important to these commenters in the future.
    The American Chemistry Council asked during the hearing why OSHA
adopted the cut-off levels 25 years ago if the Agency thought they
weren't protective, or whether there is information to indicate that
they have not been protective (Document ID  0494 Tr. 174). In
response to questions from OSHA as to what the scientific basis would
be for communicating a hazard on an SDS and not a label, they responded
(Document ID  0494 Tr. 177): ``A scientific basis? Well, most
of these are obligatory regulatory cut-offs for mixtures. There really
is not much scientific basis for any of the mixture cut-offs.'' In
other words, ACC concedes that there is also no scientific basis for
the higher cut-offs it advocates--rather the EU cut-offs are simply
policy choices made by a different authority with a distinct regulatory
structure. As described previously, OSHA believes there is evidence
that these cut-offs are no longer sufficiently protective in light of
additional information developed since the HCS was adopted in 1983.
Furthermore, having inconsistencies in information on a label versus a
safety data sheet impacts the effectiveness of the communication to
workers and downstream employers. The cut-offs/concentration levels in
the final rule are the same as proposed, and are the lower levels of
those the GHS allows countries to choose from when implementing.
    The Styrene Information and Research Center (SIRC) argues that OSHA
may not lower the mixture cut-off thresholds for sensitizers and
reproductive toxicants without establishing that a significant risk
exists at that lower threshold (Document ID 0361, 0467, and
0642). OSHA disagrees.
    As discussed in Section V, Pertinent Legal Authority, OSHA has
found that inadequate hazard communication creates a significant risk
and that the final rule will reduce that risk. Contrary to what the
SIRC says, OSHA need not support each requirement in a standard with
its own significant risk finding. Public Citizen Health Research Group
v. Tyson, 796 F.2d 1479, 1502 n. 16 (D.C. Cir. 1986). Indeed, when the
Supreme Court first construed the OSH Act as imposing a significant
risk requirement, it spoke in terms of the Agency making findings about
unsafe workplaces, not individual hazards. Benzene, 448 U.S. at 642
(``before promulgating any standard, the Secretary must make a finding
that the workplaces in question are not safe [and] * * * a workplace
can hardly be considered `unsafe' unless it threatens the workers with
a significant risk of harm''). See also, for example, id. (framing the
``significant risk'' requirement as requiring OSHA ``to make a
threshold finding that a place of employment is unsafe--in the sense
that significant risks are present and can be eliminated or lessened by
a change in practices.''); Texas Indep. Ginners Ass'n v. Marshall, 630
F.2d 398, 400 (5th Cir. 1980) (``The Supreme Court recently ruled that
the Act requires OSHA to provide substantial evidence that a
significant risk of harm arises from a workplace or employment.'').
Moreover, courts have held that the OSH Act does not require the
disaggregation of significant risk analyses along other lines. See, for
example, Lockout/Tagout II, 37 F.3d at 670 (upholding OSHA's decision
not to conduct individual significant risk analyses for various
affected industries); American Dental Ass'n v. Martin, 984 F.2d 823,
827 (7th Cir. 1993) (OSHA is not required to evaluate risk ``workplace
by workplace''); Associated Builders and Contractors, Inc. v. Brock,
862 F.2d 63, 68 (3d Cir. 1988) (``the significant risk requirement must
of necessity be satisfied by a general finding concerning all
potentially covered industries'').
    Indeed, a contrary rule would impose an unworkable burden on OSHA.
As the Third Circuit held Associated Builders and Contractors, Inc. v.
Brock, 862 F.2d 63 (3rd Cir. 1988), stating:

    The holdings in USWA I and USWA II sustained a general
significant risk finding. Assuming, however, that those opinions
were construed as leaving open the significant risk issue, as
presently presented, the outcome would be no different. This
rulemaking proceeding produced a performance-oriented information
disclosure standard covering thousands of chemical substances used
in numerous industries. For such a standard the significant risk
requirement must of necessity be satisfied by a general finding
concerning all potentially covered industries. A requirement that
the Secretary assess risk to workers and need for disclosure with
respect to each substance in each industry would effectively cripple
OSHA's performance of the duty imposed on it by 29 U.S.C. Sec.
655(b)(5); a duty to protect all employees, to the maximum extent
feasible.

Id. at 68. Thus, OSHA need not make the sort of significant risk
finding suggested by SIRC.
    Rather, once OSHA makes a general significant risk finding in
support of a standard, the next question is whether a particular
standard's requirements are reasonably related to the purpose of the
standard as a whole. Asbestos Information Ass'n/N. Am. v. Reich, 117
F.3d 891, 894 (5th Cir. 1997); Forging Indust. Ass'n v. Secretary of
Labor, 773 F.2d 1436, 1447 (4th Cir. 1985); United Steelworkers of Am.,
AFL-CIO-CLC v. Marshall, 647 F. 2d 1189, 1237-38 (D.C. Cir. 1980). The
use of a threshold to govern when the standard applies is reasonably
related to the purposes of hazard communication. It limits
communication to those situations in which a chemical is present in
sufficient quantities that workers might experience substantial
exposures to its hazards. Hazard communication can be undermined just
as much by overcommunication of risks as by undercommunication. An
avalanche of information about less significant hazards on a label or
SDS could obscure important information on substantial hazards faced by
the worker. Thresholds also save manufacturers and importers the burden
of evaluating and listing chemicals present in only small quantities
and not likely to result in substantial exposures (48 FR 53280, 53290
(Nov. 25, 1983). And as noted above, OSHA has provided a justification
for the lower levels challenged by the Styrene Institute and Research
Center: chemicals presenting these hazards may be especially hazardous
at low levels, and the potential effects are of high concern.
    In addition, SIRC seems to challenge only the reduction of the
threshold for disclosure on labels, not the identical reduction of the
threshold for disclosing the hazard on SDS for these hazards. Under the
final rule, the same information for sensitizers and reproductive
toxicants must appear on both the label and the SDS, avoiding the
potential for confusion. The reproductive toxicant and sensitizer cut-
offs are reasonably related to the purposes of the Hazard Communication
Standard.
    The courts have upheld similar requirements even in the absence of
a significant risk finding, provided the requirements were reasonable.
In National Cottonseed Products Ass'n v. Brock, 825 F.2d 482, 487 (D.C.
Cir. 1987), the court upheld medical monitoring for cottonseed workers
where OSHA found no significant risk. OSHA had eliminated the PEL but
imposed the monitoring as a ``backstop'' to the ``no significant risk''
determination, and the court upheld the monitoring requirement because
the ``evidence indicates that there is a real possibility of
significant health risks'' where no PEL was imposed. Likewise, in
National Mining Ass'n v. MSHA, 116 F.3d 520, 527-28 (D.C. Cir. 1997),
the court upheld MSHA's decision to require oxygen at a 19.5% level,
even though the evidence only showed that adverse worker effects were
experienced at a lower level of 18%. The proper minimum oxygen level
was ``a technical decision entrusted to the expertise of the agency,''
which was ``entitled to `err' on the side of overprotection.'' Id. at
528. And in Public Citizen, the court upheld a requirement to post
signs to warn employees of the hazards presented by ethylene oxide
exposures without a separate significant risk determination, noting
that signs and labels were specifically contemplated by section 6(b)(7)
of the OSH Act and a ``reasonably necessary and appropriate'' part of a
standard. 796 F.2d at 1502 n.16.
    As explained in the Pertinent Legal Authorities section, the
mixture cut-off levels are part of the HCS's general approach of
providing prophylaxis against the exposure to significant risks,
similar to the medical monitoring requirement in National Cottonseed,
the higher oxygen level requirement in National Mining Ass'n, and the
sign requirement of Public Citizen. The mixture cut-off thresholds are
supported by substantial evidence, as discussed above and, therefore,
authorized by the Act.
    A related issue is the cut-off in Category 3 of Specific Target
Organ Toxicity, both in Single Exposure and Repeat Exposure. Under the
GHS, a cut-off/concentration limit of 20% is suggested as guidance. It
is an additive cut-off, meaning that the percentages of the ingredients
that meet the definition for Category 3 would be added together and
compared to the cut-off. Consistent with other revisions to the GHS
language that are appropriate for a mandatory standard versus a non-
mandatory recommendation, OSHA proposed to make the 20% cut-off
mandatory, but requested comment on it. (74 FR 50282, Sept. 30, 2009;
see also A.<IP_ADDRESS> and A.<IP_ADDRESS>.) A limit that is not mandatory will
be difficult for chemical manufacturers to know how to comply with, and
it will also be difficult for OSHA to enforce. Furthermore, OSHA views
this provision as relaxing the current requirement, which is a cut-off
of one percent for each of the ingredients in the mixture that are in
and of themselves hazardous. However, consistent with A.<IP_ADDRESS>, if the
classifier has information that the hazard will be evident below the
specified concentration limit, the mixture is to be classified
accordingly. Therefore, where the 20% is too high, the classifier will
nevertheless be required to classify it appropriately below that level.
    There were a number of commenters who supported making the 20%
level mandatory, suggesting that it was reasonable for the U.S.,
promoted consistency, and that the level could be lower if data warrant
(See, e.g., Document ID 0313, 0324, 0327, 0329, 0330, 0338,
0339, 0353, 0365, 0381, 0410, and 0412). Others did not agree (Document
ID 0323, 0328, 0344, 0376, 0379, 0382, 0393, 0399, and 0405).
Some of these commenters suggested that OSHA should provide data to
support making it mandatory. The GHS is drafted in voluntary terms, but
the HCS is a mandatory standard, meaning that all of its provisions are
mandatory as well. OSHA is unaware of specific data one way or the
other on the question, but notes that this is a significant relaxation
of the applicable cut-off under the current rule. Given the minor
hazard presented by these chemicals, OSHA believes the 20% cut-off is
appropriate to guard against overwarning. Because no alternatives were
presented (other than making the provision voluntary, which is not an
acceptable solution), OSHA has included the mandatory requirement in
the final rule. Again, as noted above, chemical manufacturers or
importers are still required to classify mixtures at lower
concentrations if they have evidence that it presents a hazard, so OSHA
does not believe the final rule is less protective.
    Acute toxicity. In Appendix A, Chapter A.1 (``Acute Toxicity''),
OSHA proposed to adopt GHS Categories 1 through 4, but not 5. The
current

coverage of the HCS is greater than Category 3 of the GHS, but does not
include all of Category 4. If OSHA were to adopt only three categories,
it would reduce protections with regard to acute toxicity. Adopting
Category 4 expands coverage somewhat. However, chemicals meeting the
definition of Category 4 are already covered under the national
consensus standard on labeling that many chemical manufacturers already
follow (ANSI Z129). In addition, the EU covered them under their
previous classification, packaging, and labeling of dangerous
substances (Directive 67/548/EEC) and preparations (Directive 1999/45/
EC) directives, and their adopted GHS provisions. These countries
comprise the largest trading partner in chemicals for the U.S. Thus,
many manufacturers are already classifying their chemicals as acutely
toxic to comply with European requirements.
    Adopting Category 5 would not only expand coverage significantly,
it would lead to inconsistency with Europe and with the current
national consensus standard. OSHA also believes that exposures of this
magnitude are not likely to be encountered in the occupational setting,
and that such coverage would be excessive.
    Since OSHA raised this issue for comment in the ANPR, a number of
respondents specifically addressed acute toxicity. The responses
varied, although a number supported the approach proposed to cover
through Category 4 (Document ID 0021, 0046, 0047, 0077, 0104,
0123, 0135, 0145, 0155, 0163, and 0171). For example, Dow (Document ID
0047) stated:

    Dow believes that OSHA should adopt all health hazard criteria
and categories, except Acute Toxicity Category 5. While this
category may be useful for characterizing consumer products, its use
with the substances characterized under the HCS would be confusing
and unnecessary. Dow understands that the EU and Australia have both
chosen not to include Acute Toxicity Category 5 in their
implementation of the GHS and that Canada is currently considering
doing the same. Dow believes that the U.S. should be consistent with
these other major trading partners by not including this category
when it adopts the GHS.

    Others suggested that OSHA propose to adopt Categories 1 through 3
(Document ID 0034, 0128, and 0141). Some argued that all
categories should be adopted to ensure harmonization (See, e.g.,
Document ID 0018, 0036, 0050, 0078, 0106, and 0116).
    OSHA believes that coverage provided by Categories 1 through 4 is
appropriately protective for the workplace, and leads to the greatest
harmonization with workplace authorities in other countries. With
regard to coverage provided by Category 5, OSHA does not preclude
inclusion of information on Category 5 on the label or the SDS. Thus
chemical manufacturers or importers who wish to have one label that
suffices for the workplace and the consumer sector, for example, could
do that and still be in compliance with the HCS. As noted earlier,
commenters on the NPRM supported the categories chosen by OSHA, except
for a few who thought OSHA should adopt all categories in the GHS to
promote complete harmonization. However, OSHA believes that this
concern is addressed by permitting such categories to be addressed on
labels and SDSs with no penalty.
    OSHA did not propose to adopt Category 5. The final standard does
not adopt Category 5, nor include it in Table A.1.1, which describes
the criteria for acute toxicity. However, calculations for the acute
toxicity of mixtures that are comprised of one or more ingredients that
fall into Category 5 must include the acute toxicity estimate for the
Category 5 ingredients. Proposed Paragraph A.<IP_ADDRESS>(a) indicated that
the calculation of the acute toxicity of mixtures would ``[i]nclude
ingredients with a known acute toxicity, which fall into any of the
acute toxicity categories.'' This is consistent with the GHS
(Subparagraph <IP_ADDRESS>.1(a)).
    As discussed in the Proposal, OSHA believes that the exclusion of
Category 5 from the criteria Table A.1.1 may lead to classifiers
overlooking substances falling into this category in the mixture
calculation, which could result in a higher (less protective)
classification. This could also mean a lack of harmonization within the
U.S. if other Federal agencies adopt Category 5, potentially requiring
inclusion of these data in the calculation. To avoid this situation,
OSHA has clarified the text for the mixture calculation to ensure that
the ingredients that would be classified as Category 5, and thus would
not be classified under the HCS, are included in the mixture
calculation. Paragraph A.<IP_ADDRESS>(a) has been modified to indicate the
calculation must ``[i]nclude ingredients with a known acute toxicity,
which fall into any of the acute toxicity categories, or which have an
oral or dermal LD50 greater than 2000 but less than or equal
to 5000 mg/kg body weight (or the equivalent dose for inhalation);''.
    OSHA has modified the text of Note (d) to Table A.1.1 to help
clarify the requirements. This was done in response to a comment from
Dow (Document ID 0526), which stated that they were ``confused
about the table,'' and that OSHA should revisit the table and the
definitions to properly harmonize the provisions.
    Several commenters noted that there were errors in Table A.1.2 in
the NPRM (Document ID 0376, 0393, and 0405). The errors have
been corrected in the final rule.
    One commenter stated that the criteria seem to assume that acute
lethality data are available in all situations, and they are not
(Document ID  0321). As with all other health hazard criteria
in the standard, the HCS does not require data to be generated to
comply with the standard. And the final rule recognizes that many
chemicals have not been tested to ascertain their hazards. For example,
the formula used to calculate the acute toxicity of a mixture makes an
adjustment for ingredients whose acute toxicity is unknown. In
addition, the fact that a mixture contains an ingredient of unknown
toxicity must be indicated on the label and SDS. This is important
because in some mixtures the unknown percentage could be significant,
and therefore the estimation of toxicity for the mixture has less
credibility than in a situation where the majority of the ingredients
have data available.
    It was also suggested that the formula used for acute toxicity be
displayed in a way that is more commonly used for such equations
(Document ID 0641). OSHA agrees that it could be displayed in
a different way, but wanted to ensure it appeared the same in the
regulatory text as it appears in the GHS. However, in guidance for
application of the final rule, OSHA will include the formula in the
alternative format as well to assist in understanding it.
    The Styrene Information and Research Center (SIRC) challenged the
proposal's requirement to disclose the concentration of ingredients in
a mixture whose acute toxicity was unknown (Document ID 0361).
It argued that ``[i]t is unclear how that requirement would pass a
significant risk test'' and that ``[i]t seems unlikely to make the user
more cautious.'' However, the record shows the contrary. Both workers
and union representatives testified at the public hearing on this
rulemaking that workers would be more cautious when dealing with
chemicals of unknown toxicity and would look for substitutes where
possible (Document ID 0494). Further, Cathy Cole, President of
the American Industrial Hygiene Association, testified that industrial
hygienists use the fact that a chemical's acute toxicity is unknown
when they perform qualitative risk

assessments. She testified (Document ID 0496 Tr. 425):

    [W]e would take that information and use it to weigh it against
all the other information within that mixture. If there's an
unknown, then we would most likely provide a safety factor as we did
our risk assessment * * *. If there's a mixture that has a number of
unknowns, then we would treat that very carefully and we would have
a high risk ranking for it.

    The final rule's hazard classification scheme for mixtures
presenting acute toxicity hazards treats unknown toxicity in a similar
way. When testing data on the mixture as a whole are not available, the
acute toxicity of the mixture is determined by assuming that the
nontoxic ingredients dilute the toxicity of the acutely toxic
ingredients. (See A.<IP_ADDRESS>.) However, where the acute toxicity of a
particular ingredient is not known, the final rule excludes it from the
toxicity calculation. (A.<IP_ADDRESS>.4.) In effect, this means that
ingredients with unknown toxicity are assumed not to dilute the
toxicity of the known acute toxicants. This approach reflects the same
cautious treatment of ingredients having unknown acute toxicity that
the witnesses testified to, as discussed above. In addition, it is
necessary to disclose the concentration of ingredients with unknown
toxicity because downstream users need that information to classify any
products they make with the mixture.
    OSHA has also made two minor, clarifying changes to paragraph
A.<IP_ADDRESS>.4 that are consistent with changes that were approved by the
UN Sub-committee in December. The word ``relevant'' has been added in
front of ``ingredient,'' and the word ``total'' was deleted before
``percentage.'' Therefore, A.<IP_ADDRESS>.4 in the final rule requires that
if the total concentration of the relevant ingredient(s) with unknown
acute toxicity is <=10% then the following formula must be used:
[GRAPHIC] [TIFF OMITTED] TR26MR12.047

    However, if the total concentration of the relevant ingredient(s)
with unknown acute toxicity is >10%, the formula presented above is
corrected to adjust for the percentage of the unknown ingredient(s) as
follows:
[GRAPHIC] [TIFF OMITTED] TR26MR12.048

    The above discussion shows that SIRC's concerns about the unknown
toxicity requirement are unfounded. Employers use the fact that a
chemical's acute toxicity is unknown in determining how chemicals
should be handled. As such, the disclosure requirement is reasonably
related to the purpose of hazard communication and, therefore, within
OSHA's authority. In addition, by providing the worker with information
about the limits of the known information, the requirement provides the
sort of prophylactic function that has been upheld even in situations
where the Agency has not made a significant risk finding. The unknown
toxicity requirement is consistent with the OSH Act.
    Another commenter suggested the trade secret provisions should
apply to the requirement for disclosing the concentration of
ingredients with unknown toxicity (Document ID 0353). The
revised rule (and the GHS) do not suggest that the names of the
components be disclosed--simply the aggregate percentage of the total
composition that has unknown acute toxicity. So if there are three
ingredients in a mixture that have no acute toxicity data available,
and they comprise 20% of the mixture, the label and SDS must indicate
that 20% of the mixture has unknown acute toxicity. The names of the
chemicals do not have to be disclosed, and neither does the number of
chemicals involved. Therefore, there should be no trade secret issue.
    Skin corrosion/irritation. OSHA proposed to adopt Categories 1 and
2, but not Category 3, for skin corrosion/irritation. Category 3 covers
more than the criteria for this hazardous effect under the current HCS.
In addition, the irritant effects covered by Category 3 are very minor
and transient, and of limited applicability in the workplace setting.
The Agency received several ANPR comments supporting such an approach
(Document ID 0034, 0077, 0128, 0145, and 0171). This approach
is also consistent with the European Union.
    As OSHA noted in the preamble to the NPRM (74 FR 50392-93, Sept.
30, 2009), significant editing was done to the GHS text for this health
hazard. The criteria in the GHS lead the evaluator to conduct
additional testing when information is not available. While the GHS
does not require testing, the criteria imply that it should be done to
complete an evaluation. This implication is not acceptable under the
HCS, which is based solely on available evidence.
    As noted in the NPRM discussion, work had already been initiated in
the UN Sub-committee to modify the chapter on skin corrosion/irritation
to address inconsistencies and clarify provisions. That work has
proceeded since the NPRM, and is on the work program for the next two
years as well. OSHA has made modifications to the HCS criteria to
reflect discussions in the Sub-committee, and clarify areas of concern.
In particular, Chapter A.2 of Appendix A, ``Skin Corrosion/
Irritation,'' was reorganized in the final rule so that text and
figures are consistent. Paragraph A.2.1's title was changed to
``Definitions and general considerations.'' Paragraph A.2.1.2 was added
to introduce a tiered approach to follow when classifying for skin
corrosion/irritation. Paragraph A.2.2, ``Classification criteria for
substances using test data,'' has been modified to reflect that it
covers animal test data. In Paragraph A.2.3, ``Irritation,'' the
factors used to determine the corrosion/irritation potential of a
substance were deleted, and the text was reorganized to follow the
tiered approach to classify substances using other data elements.
Figure A.2.1 was updated to make it consistent with the text, and to
show the tiered evaluation scheme instead of a testing scheme. Comments
had been received that indicated this figure was confusing (Document ID
0344 and 0381). Another commenter noted that the criteria are
provided without indicating how they were derived (Document ID
0321). The criteria were developed by a group of experts in
the OECD and were derived from the existing criteria of the countries
involved. They do not specify a test method because the GHS is test
method neutral, but the OECD testing guidelines are generally agreed to
provide the type of information needed for classification under the
GHS.
    There were also several comments that pH criteria are not
appropriate to use in some situations (for example, the pH of the
ingredients in a mixture may not predict the pH of the mixture)
(Document ID 0321, 0335, and 0381). The criteria recognize
that test data for these effects provide better information

to base a classification on, but pH information can be of assistance
when such data are not available.
    OSHA believes the edits and changes make the chapter less confusing
and clarify that testing is not required to achieve compliance. The
basic provisions and approach remain the same as the GHS. The Agency is
participating in the continuing work of the UN Sub-committee on this
topic, and will revise the HCS if any additional clarifications are
made in the criteria for these hazards that will help classifiers
follow the provisions.
    Serious eye damage/irritation. Proposed Appendix A, Chapter A.3
(``Serious Eye Damage/Eye Irritation''), did not include the criteria
for Category 2B of eye irritation, but addressed the label elements for
the category in Appendix C. A number of commenters indicated that OSHA
should include the criteria for Category 2B (Document IDs
0344, 0351, 0367, 0371, 0381, and 0393), clarify coverage of
Category 2B (Document ID 0376 and 0382), or exclude it
(Document ID 0405). The omission of the criteria was an
oversight, and OSHA has added the criteria for Category 2B to the final
rule.
    The text for GHS Chapter 3.3, ``Serious Eye Damage/Eye
Irritation,'' posed similar issues to those described above for skin
corrosion/irritation. The criteria in the GHS implied that testing
might be needed to complete classification in the absence of data. This
is required by neither the GHS nor the HCS. OSHA made a number of
modifications to the parallel text in Appendix A, Chapter A.3, of the
HCS proposal to address the perception that testing might be required
when it is not. And the UN Sub-committee is also reviewing this chapter
for purposes of clarifying the requirements.
    As with the skin chapter, in the final rule OSHA has reorganized
Chapter A.3 so that the text and figures are consistent, and so that it
is clear that what must be followed is a tiered approach. The title of
A.3.1 was modified to indicate it covers definitions and general
considerations, and paragraph A.3.1.2 was added to introduce the tiered
approach for classification. Paragraph A.3.2 (``Classification criteria
for substances using animal test data'') was modified to indicate it
addresses animal data. Table A.3.1 was modified to indicate that
Category 1 corresponds to Serious Eye Damage and not to eye irritants,
and Table A.3.2 adds the criteria for Category 2B. In A.3.3
(``Classification criteria for substances using other data elements''),
the classification criteria for substances were reorganized using other
data elements to make it consistent with Figure A.3.1, and to show the
tiered evaluation strategy for classification. Figure A.3.1 was updated
to make it consistent with the text. And Table A.3.3 now has a note to
indicate that a mixture may be classified as Category 2B in cases when
all relevant ingredients are classified as Category 2B. As with skin
corrosion/irritation, OSHA will continue to monitor work in the UN Sub-
committee to clarify these criteria, and will modify the rule to update
the chapter as necessary if changes are made.
    One additional issue was raised concerning the coverage of the GHS
criteria for eye irritation in comparison to current criteria used by
CPSC and EPA. The National Toxicology Program Interagency Center for
the Evaluation of Alternative Toxicological Methods (NICEATM) (Document
ID 0384) suggests that the GHS criteria are not as protective
as the current criteria used by CPSC and EPA. OSHA uses the CPSC
criteria in the current HCS, but does not use EPA criteria. NICEATM did
an analysis of a group of chemicals to determine what their
classifications would be under the different criteria, and concluded
that at least 14 of 149 chemicals it reviewed (17%) would not be
classified under the GHS criteria, but would have been under current
HCS criteria.
    OSHA asked a consulting toxicologist familiar with the GHS criteria
to review the comment and the analysis, and the results of his review
have been entered into the public record (Document ID 0576,
0577, and 0578). The results of this review show that all of the 14
chemicals are differently classified because they present transitory
effects that resolve in 72 hours or less; the difference in
classification results from the way each method accumulates transitory
positive results across test animals. While there may be some
differences in conclusions made under the differing criteria, the
differences are less pronounced when variance in transient effects is
considered (as it is under the criteria as proposed). This is explained
as follows in the toxicologist's report:

    In order to compensate for this difference in approaches, OSHA
has proposed to also adopt the GHS concept of ``pronounced
variability''. Under this concept, for those chemicals where there
is pronounced variability among animal responses, such information
may be taken into account in determining the classification. As
discussed specifically under OSHA's proposed criteria for
Classification and Categorization of Skin Corrosion/Irritation, but
only mentioned in passing under Serious Eye Damage/Eye Irritation,
this notion would allow for classification in cases where there are
very definite, positive irritant effects related to chemical
exposure in a single animal, but the overall data set does not
support classification. In cases where the response is borderline
but persistent or severe but transient, the Assessor would likely
classify a substance as irritating. It is noted that there are at
least two chemicals among those under examination where ``pronounced
variability'' would likely cause the Assessor to classify them as
irritants (see data for ethyl thioglycolate and glycidyl
methacrylate; fomesafen, 2,2-dimethyl-3-pentanol, and cellosolve
acetate might also be classified as irritants under this concept).

The final rule retains the pronounced variability language at A.<IP_ADDRESS>
and A.3.2.3. The toxicologist also noted that:

    Finally, a quick search of secondary and tertiary sources
available on-line indicates that 12 of the 14 chemicals in question
would be classified as hazardous materials under both the current
and proposed classification criteria. Those that would not be
classified are N,N-dimethylguanidine sulfate (sub-EU classification
eye and skin irritation responses; not a sensitizer; no other data
found); and tetraaminopyrimidine sulfate (not an acute or chronic
toxicant; identified as non-irritating by EU Scientific Committee on
Cosmetic Products and Non-Food Products intended for Consumers
(SCCNFP)).

Therefore, although the chemical may not be addressed as an eye
irritant, it would still be considered a health hazard under the GHS--
and the HCS--and thus have information available about its effects on
labels and SDSs.
    While OSHA appreciates the concerns raised by NICEATM, the criteria
are being finalized as proposed, other than the modifications made for
clarification purposes. It appears that the pronounced variability
considerations will address some of the concerns raised, and that the
primary remaining differences involve transient effects of relatively
low concern. Both CPSC and EPA were involved in the development of the
criteria in the GHS, and were aware of the differences between their
existing systems and the agreed harmonized criteria. In harmonizing
between the existing systems, the criteria selected were between what
currently exists in the U.S. and in the EU. The classification criteria
in each existing system is not a bright line determined by science, but
rather a scientifically influenced policy determination, and as
discussed elsewhere, an inevitable part of adopting harmonized criteria
is that a few borderline chemicals might be dropped. No other
stakeholders have raised the issue of whether the criteria are
protective enough. OSHA is proceeding with the final rule because it
believes that in this situation,

maintaining harmonization with the GHS is ultimately more important for
worker health. This situation will continue to be monitored as
implementation takes place to ensure that it is appropriate.
    Respiratory or skin sensitization. The final rule makes only minor
changes to the proposed text of Appendix A, Chapter A.4, ``Respiratory
or Skin Sensitization.'' The footnotes have been re-numbered since they
were out of sequence in the NPRM. And the term EC3 has been explained
in a footnote to Tables A.4.3 and A.4.4 (estimated concentration of
test chemical required to induce a stimulation index of 3 in the local
lymph node assay).
    The GHS criteria for respiratory and skin sensitizers have one
category for each type of sensitization, but also give the option of
dividing that one category into two sub-categories, which involves a
differentiation in the type of evidence available. In the NPRM, OSHA
proposed to adopt the sub-categories for classification. One commenter
strongly supported adopting sub-categories for these sensitizers
(Document ID 0381), while another did not support it because
the EU has not adopted sub-categories (Document ID 0376). OSHA
is adopting the sub-categories as proposed. However, the Agency
recognizes that there are situations where data are not available to
place the chemical into one of the sub-categories. The GHS itself
addresses this in <IP_ADDRESS>.1.1 (respiratory sensitization), and
<IP_ADDRESS>.1.1 (skin sensitization). Therefore, under the revised HCS,
simply classifying the chemical as Category 1 will be sufficient in
cases where data are insufficient to assign a subcategory. The American
Chemistry Council (Document ID 0393) suggested that more
guidance is needed to differentiate potential and severe sensitizers
for placement into the sub-categories. OSHA believes that this type of
guidance should be developed through the Sub-committee process, rather
than by countries independently developing guidance for application.
The Agency will consider requesting the Sub-committee to develop such
guidance.
    Germ cell mutagenicity. The comments on this health hazard centered
on whether or not it should be included in Appendix A. Procter & Gamble
(Document ID 0381) and the American Chemistry Council
(Document ID 0393) argued that it should not be included. The
Soap and Detergent Association (Document ID 0344) also argued
for exclusion, but said if it is included, only Category 1A should be
covered. Ecolab (Document ID 0351) also argued that only
Category 1A should be covered. These commenters argued that it is
already covered by reproductive toxicity and carcinogenicity, and
adding a separate hazard class would create a training burden.
    OSHA disagrees. First, while the current HCS does not define
mutagenicity as a separate health hazard, it is covered by the
reproductive toxin definition. Under the GHS, mutagenicity is not
covered by reproductive toxicity, and OSHA's failure to adopt the
mutagenicity category would render the final less protective than the
current HCS. The hazard class will have to be adopted to maintain
coverage. Secondly, though mutagenicity data are used to predict
carcinogenicity, the mutagenicity hazard is not covered by the
carcinogenicity criteria. Furthermore, little additional burden for
training can be claimed for what is already covered under reproductive
toxicity in the current HCS.
    All of these commenters argue that the HCS should be as consistent
with the EU as possible. The EU has already adopted these criteria, so
excluding them would not be consistent with the EU. OSHA is maintaining
the hazard class as part of the HCS, and including both categories. It
is OSHA's understanding that at present there are no chemicals that
meet the criteria for Category 1A, so currently this has no burden
associated with it--although there may be minimal burdens if new data
in the future place chemicals in this category. (See, e.g., Annex VI to
the EU's former directive on classification and labeling, which states:
``To place a substance in category 1, positive evidence from human
mutation epidemiology studies will be needed. Examples of such
substances are not known to date. It is recognized that it is extremely
difficult to obtain reliable information from studies on the incidence
of mutations in human populations, or on possible increases in their
frequencies.'') Chemicals in Category 2 are frequently used already in
discussions of potential carcinogenicity, since mutagenicity test
results are used to predict carcinogenicity. Thus, there is little
burden associated with adopting that category either. Therefore, OSHA
has retained Appendix A, Chapter A.5, ``Germ Cell Mutagenicity.''
    OSHA included a new heading in A.5.4 entitled ``Examples of
scientifically validated test methods.'' In the interest of maintaining
current protections, as well as being consistent with implementation in
the EU, germ cell mutagenicity is adopted in the final rule as
proposed.
    Carcinogenicity. The primary change to the carcinogenicity hazard
class as proposed in Appendix A, Chapter A.6, ``Carcinogenicity,'' is
the addition of A.6.4, ``Classification of carcinogenicity.'' In the
current HCS, carcinogenicity was determined in part by consulting the
National Toxicology Program's biennial Report on Carcinogens (RoC), or
the International Agency for Research on Cancer's monographs. In
addition, chemicals that are regulated by OSHA based on their
carcinogenicity (i.e., there is a substance-specific standard
addressing the chemical, and the chemical poses a risk of
carcinogenicity), are always covered by the HCS. The IARC and NTP
documents are prepared based on the evaluation of data by experts
convened by these organizations. A number of commenters suggested that
this should still be permitted under the GHS-aligned criteria. For
example, the United Steelworkers argued (Document ID 0403):

    The current Hazard Communication standard includes a reference
to several lists of chemicals automatically presumed to be
hazardous, such as the lists of carcinogens published by the
National Toxicology Program (NTP) and the International Agency for
Research on Cancer (IARC). The proposal removes references to such
lists, in favor of a more detailed and complicated classification
system. While that classification system is required by the GHS, the
lists provide useful guidance and should not be removed altogether.
    We suggest the following compromise: OSHA should state in the
regulatory text that a classifier may presume that the presence of a
chemical on one or more of those lists is sufficient to classify the
chemical as hazardous with respect to the hazard covered by the
list. (OSHA should also state that the inverse is not true: The
absence from a list does not indicate the lack of a hazard.) This
does not mean that the classifier is required to classify a chemical
as hazardous based solely on the list, only that he or she is free
to do so. OSHA should also indicate in the preamble that the Agency
will use the lists as guidance in enforcement, and that a classifier
who ignores the lists should be prepared to show why his or her
judgment is better than the judgment of, for example, NTP or IARC.

Similarly, Morganite Industries, Inc. and Morgan Technical Ceramics,
stated (Document ID 0321):

    For example, IARC, NTP and other qualified organizations assess
carcinogenicity and come to published conclusions. We do not
understand why the proposed Hazard Communication Standard
establishes procedures for chemical suppliers to conduct such
assessments, seemingly asking them to conduct their own evaluations
in the manner

of similar to these expert agencies. That makes no sense to us. Why
not just refer to the conclusions published by these agencies? That
would shorten and simplify the regulation, it would eliminate large
parts of the difficult language and it would eliminate regulatory
requirements that are in fact infeasible for most preparers of MSDS
to comply with.

    OSHA agrees with these commenters that allowing evaluators to rely
on IARC and NTP could make classification easier for them, as well as
lead to greater consistency. Therefore, A.6.4.1 has been added to the
criteria in the final rule to indicate that classifiers may treat these
sources as establishing that a chemical is a carcinogen without
applying the criteria themselves. And A.6.4.2 reiterates that OSHA-
regulated carcinogens are covered under the HCS.
    In order to facilitate the use of IARC and NTP determinations as
sources for purposes of classification, non-mandatory Appendix F has
been significantly modified. In the NPRM, Appendix F was simply a
verbatim quote of guidance from IARC on determining carcinogenicity. In
the final rule, Appendix F has been updated to reflect the latest
version of that IARC text, but also includes additional guidance on how
to use IARC and NTP to make carcinogenicity classifications. The
inclusion of this guidance should make classification easier for
chemicals addressed by these sources, and should also provide
parameters for the type of weight-of-evidence decisions that are
appropriate under the GHS-aligned criteria.
    The following table is included in Part D of Appendix F, and may be
used to perform hazard classifications for carcinogenicity under the
HCS. It relates the approximated GHS hazard categories for
carcinogenicity to the classifications provided by IARC and NTP, as
described in Parts B and C of Appendix F:

                              Table XIII-2
------------------------------------------------------------------------
    Approximate equivalences among carcinogen classification schemes
-------------------------------------------------------------------------
              IARC                        GHS               NTP RoC
------------------------------------------------------------------------
Group 1.........................  Category 1A.......  Known.
Group 2A........................  Category 1B.......  Reasonably
                                                       Anticipated (See
                                                       Note 1).
Group 2B........................  Category 2 .......
------------------------------------------------------------------------
Note 1:
1. Limited evidence of carcinogenicity from studies in humans
  (corresponding to IARC 2A/GHS 1B);
2. Sufficient evidence of carcinogenicity from studies in experimental
  animals (again, essentially corresponding to IARC 2A/GHS 1B);
3. Less than sufficient evidence of carcinogenicity in humans or
  laboratory animals; however:
a. The agent, substance, or mixture belongs to a well-defined,
  structurally-related class of substances whose members are listed in a
  previous RoC as either ``Known'' or ``Reasonably Anticipated'' to be a
  human carcinogen, or
b. There is convincing relevant information that the agent acts through
  mechanisms indicating it would likely cause cancer in humans.

    While the criteria for carcinogenicity (as well as other health
effects) are largely based on weight of evidence evaluations, there are
also provisions in the GHS for countries that want to ensure that all
potential carcinogens are adequately captured by the criteria. Thus
paragraph <IP_ADDRESS> of the GHS chapter on carcinogenicity states:

    * * * For inclusion into Safety Data Sheets, positive results in
any carcinogenicity study performed according to good scientific
principles with statistically significant results may be considered.

OSHA chose to include this requirement in Figure A.6.1 of Appendix A in
the NPRM under Category 2, suspected human carcinogen. Specifically,
the statement read:

    Positive results in any carcinogenicity study performed
according to good scientific principles with statistically
significant results qualifies for referencing the chemical as, at
the least a Category 2 carcinogen.

    The Styrene Information and Research Council (SIRC) (Document ID
0361) argues that the ``one positive study'' criterion is
inconsistent with the weight of evidence approach. In fact, it is not
part of the weight of evidence approach, but rather reflects the
Agency's decision to ensure that the current level of protection in
terms of identifying potential carcinogens in the workplace is
maintained in the HCS as permitted by the GHS provisions.
    SIRC also indicated that it is not clear what is meant by
``referencing'' the chemical as, at the least, a Category 2 carcinogen.
OSHA agrees that the inclusion of this language in Figure A.6.1 is not
as clear as it could be in terms of what is required. In the final
rule, OSHA has separated this requirement from Category 2, and added a
new heading of ``Other considerations'' to the table. The text for the
``Other considerations'' is: ``Where the weight of evidence for the
carcinogenicity of a substance does not meet the above criteria, any
positive study conducted in accordance with established scientific
principles, and which reports statistically significant findings
regarding the carcinogenic potential of the substance, must be noted on
the safety data sheet.'' Categories 1 and 2 will remain based on weight
of evidence, but the data that meet the definition of ``other
considerations'' must also be provided on the SDS for the chemical.
This will maintain the protections of the current rule and provide
information to downstream users so they can determine the appropriate
protective measures to be taken in these situations.
    In paragraph A.6.3.2 of the NPRM, OSHA included the mixture
approach in GHS paragraph <IP_ADDRESS> regarding use of test data as a whole
to characterize the carcinogenic potential of a mixture:

    A mixture may be classified based on the available test data for
the mixture as a whole. In such cases, the test results for the
mixture as a whole must be shown to be conclusive taking into
account dose and other factors such as duration, observations and
analysis (e.g., statistical analysis, test sensitivity) of
carcinogenicity test systems.

SIRC (Document ID 0361) similarly took issue with this
provision:

    Again, the use of the word ``conclusive'' appears to be an
inappropriate attempt to apply the European Precautionary Principle
to this issue. It is inconsistent with the fundamental principle
that hazard communication is to be based on the application of
expert judgment to known information and not require chemical
testing (either explicitly or as an inevitable practical requirement
to avoid unacceptable economic consequences). The word
``conclusive'' should be replaced with the word ``adequate'' or
``persuasive.''

The provision in A.6.3.2 recognizes that it is difficult to accurately
characterize the carcinogenicity of a mixture with an ingredient that
is clearly carcinogenic. It requires skilled, expert judgment, and test
results on the mixture as a whole may be misleading. Therefore, the

experts who developed the carcinogenicity criteria believed that given
the critical nature of this effect and the known limitations of
assessing carcinogenic potential in a mixture, it was appropriate to
allow testing of the mixture as a whole to supersede an evaluation
based on the carcinogenic potential of a known ingredient only when the
data allow a sufficient level of confidence about the mixture's
hazards. OSHA agrees with the findings of these experts, and does not
believe that the word ``conclusive'' needs to be replaced. This
provision remains the same in the final rule. It also does not require
or imply that any testing of chemicals be performed. It is actually
rather unusual to have mixtures tested for any types of effects, so it
is expected that this provision will not be applied frequently. If a
test is performed voluntarily with the purpose of avoiding
characterization of a mixture as a carcinogen, it is very important
that the test provide conclusive evidence before depriving downstream
users of information that ingredients in the mixture present a
carcinogenicity hazard.
    In addition to the technical considerations, SIRC (Document ID
0361) (as well as SPI, Document ID 0392), repeatedly
suggests that the precautionary principle, or European approaches, are
the genesis of various provisions. First, OSHA does not agree that the
precautionary principle had any part in the GHS, or the HCS,
provisions. The HCS is an information transmittal standard, not a
standard that requires the implementation of controls or other risk
management approaches. The precautionary principle generally applies to
competent authorities, and allows them to regulate or establish
controls in situations where complete information is not available
about the situation. That certainly does not apply to this provision in
the HCS, which requires definitive data before allowing a chemical
manufacturer or importer to designate a mixture as not being
carcinogenic, although it contains an ingredient that clearly has a
carcinogenic potential. The HCS is a standard that is intended to
provide information to users of chemicals so they can make their own
determinations as to what controls are needed to prevent adverse health
effects or the effects of physical hazards. The better information they
have about the chemicals in their workplaces, the more likely they will
be able to make their own risk assessments, and choose appropriate risk
management measures. The provisions of the HCS--as well as the GHS--are
designed to ensure that such information is available to users.
    The criteria proposed are adopted in the final standard, with the
addition of the paragraphs referring to NTP, IARC, and OSHA-regulated
substances, and supplemented by the revised non-mandatory Appendix F.
    Reproductive toxicity. This hazard class, described in Appendix A,
Chapter A.7, was proposed to have two hazard categories (Category 1,
which is subdivided into two sub-categories based on human evidence,
and Category 2, which also includes evidence from animal studies). In
addition, it requires consideration of effects on or via lactation.
Several commenters argued that OSHA should not adopt effects on or via
lactation (Document ID 0344, 0351, and 0381). The rationale
provided is that there is no standard assessment method. However, the
criteria already recognize that there is no standard assessment method,
and provide the types of information that can be used to assess whether
a chemical poses this effect. While such information may not be
available for many chemicals, there are certain types of products that
may have such information available, and it is information that needs
to be provided to exposed workers. Therefore, OSHA is maintaining
effects on or via lactation in the final rule. In addition, this
maintains consistency with the EU approach.
    The only change OSHA has made in the final rule is to change
``should'' to ``shall'' in A.<IP_ADDRESS>, since it is mandatory in the HCS.
Otherwise, the criteria are adopted as proposed in the text of the
final rule.
    Specific target organ toxicity single exposure (STOT-SE). This
hazard class, described in Appendix A, Chapter A.8, was proposed to
have three categories. The first two categories deal with differences
in the type of evidence available to assess the effect, while the third
addresses transient target organ effects, such as narcotic effects and
respiratory irritation. Several commenters indicated that Category 3
could be adopted without adopting Category 2 (Document ID
0344, 0351, 0381, and 0393). Procter & Gamble (P&G) (Document
ID 0381) argues that Category 2 should not be adopted:

    There are also a significant difficulty and potential unintended
outcome that weigh against applying Category 2. Animal studies may
be done for a variety of purposes, some of which are not relevant to
consumer product uses, and the interpretations of animal data from
these types of studies often yield conclusions not relevant to
consumer products. Using the outcomes from animal studies for
classification into Category 2, especially studies at exposures near
the point of morbidity, requires an unusual level of expertise that
many classifiers would not possess. In addition, classification into
Category 2 relies on interpretation of the phrase ``relevant to
human health,'' which would involve an additional expertise.
Therefore, Category 2 should not be adopted.

    There are a number of difficulties with this argument. First, this
section addresses protection of workers exposed to chemicals, and not
the assessment of consumer products and exposures. Many consumer
products are not covered by the HCS, although provisions in the scope
and application cover those products where they are used in the
workplace in a manner different than consumers would use them, or with
a more extensive duration and frequency of use.
    In devising the Category 1/Category 2 approach to classifying
specific target organ toxicity after single (and repeated) exposure,
the framers of the STOT-SE (and STOT-Repeated Exposure) criteria sought
to establish a means by which the chemical manufacturers and importers
could communicate to the worker information as to both the nature and
the severity of adverse systemic and target organ effects. The final
rule provides detailed criteria to clarify what would be considered an
``adverse'' effect (See A.<IP_ADDRESS>.3), and it also provides specific
examples of effects (``changes'') that might be seen in animal studies,
yet would not be considered to be ``adverse'' (A.<IP_ADDRESS>).
    Using these criteria and examples, classifiers will be able to
consider whether a change was, as required by Category 2, ``of
relevance for human health.'' In specific cases when an evaluated
change was deemed not to be relevant, the classifier is allowed to
discount specific toxicological study findings that are not relevant to
human hazard assessment and not classify. OSHA believes that
classification under Category 2 will be no more difficult than other
hazards under the rule, and that no ``special additional experience''
will be needed to classify for Category 2, as suggested by P&G.
    Additionally, the GHS-based STOT criteria proposed for adoption by
OSHA sought to introduce the concept of dose response to the
communication of specific target organ toxicity hazards. Such a concept
has long been part of the assessment of acute toxicity hazards, but has
been missing from the communication of many other health hazard
endpoints. Adoption of both Categories 1 and 2, as proposed, allows the
chemical manufacturer/importer of a chemical to convey to the worker
additional information as to the

characterization of the specific target organ hazard by providing some
general measure of whether an effect (change) might be expected at low
(presumably occupationally relevant) exposure, or whether it would be
seen only in cases of unusually high exposure (e.g., catastrophic loss
of safety controls).
    P&G also suggests that Category 2 is inconsistent with paragraph
<IP_ADDRESS> of the GHS in that ``it does not rely primarily on human data *
* *.'' However, while GHS <IP_ADDRESS> (A.8.1.3 in the final rule) does say
that human data will be the ``primary source for classification,'' it
also specifically states that classification in this hazard class may
also be made on reliable evidence ``in experimental animals,
toxicologically significant changes * * *.'' Thus, P&G's contention is
not accurate. In addition, animal data are used or referred to
throughout the criteria in the GHS for health hazards, and the use of
such data to predict effects in exposed humans is a standard
toxicological approach.
    In addition to its appropriateness for protection of workers,
Category 2 has been adopted by the EU, and adopting it in the final
rule will thus maintain consistency with the EU as well.
    Aspiration hazard. OSHA did not propose to adopt Category 2 for
aspiration hazards covered by the GHS. This category appeared to be
more appropriate for the consumer sector than the workplace. OSHA does
not specifically address aspiration hazards in the current HCS although
the Agency believes the more relevant and serious Category 1 aspiration
hazards are captured under the broad scope of the rule. Several ANPR
commenters agreed that Category 2 should not be covered in the HCS
(Document ID 0034, 0077, 0128, 0145, and 0171), and the EU
does not include it in their requirements. Others suggested that
aspiration should not be covered at all since it is not relevant to the
occupational setting (Document ID 0102, 0104, and 0163).
    Several commenters on the NPRM also argued that aspiration hazard
should be completely excluded from the revised HCS (See, e.g., Document
ID 0373, 0393, 0398, 0486, and 0528). In addition, one comment
suggested that the criteria could be interpreted as applying to
drowning, and is overbroad (Document ID 0353).
    The primary proponent for complete exclusion of aspiration as a
hazard in the revised GHS was the Hydrocarbon Solvents Panel (the
Panel) of the American Chemistry Council. In their post-hearing
comments, the Panel summarized their position as follows (Document ID
0528):

    (1) OSHA should not adopt the Aspiration Toxicity class under
the GHS because, as demonstrated by data submitted to the record,
aspiration as a route of exposure is not common in the industrial
setting, and is not a significant cause of occupationally related
severe or fatal poisonings.
    (2) Should OSHA include Aspiration Toxicity as one of the Health
Hazard classes, the Panel urged that OSHA not require the Health
Hazard Symbol be used as part of the pictogram because it does not
accurately symbolize the nature of the hazard represented by the
aspiration route of entry, and could be potentially misleading.
    (3) Should OSHA include Aspiration Toxicity and a symbol, the
Exclamation Mark symbol is more appropriate for the Aspiration
Hazard Pictogram. Of the existing symbols in the proposed rule, the
Exclamation Mark symbol is more representative of an actual
aspiration episode. The Exclamation Mark would be a better choice to
connote the hazard endpoints and response necessary in an aspiration
event, due to the immediate need for intervention in an aspiration
episode.
    (4) If OSHA is unwilling to adopt the Exclamation Mark symbol
for Aspiration Toxicity, we request that OSHA forward the concern to
the UNSCEGHS for its consideration.

With regard to the Panel's first point, OSHA agrees that this route of
exposure is not frequently found in the occupational setting. But that
is different than saying it does not occur, or should not be a concern.
NIOSH has submitted a number of studies and reports to the record that
document concerns about aspiration (Document ID 0523 and
0524), and address occupational exposures as well (Document ID
0523). For example:

    Amoruso et al. [2008] reported that aspiration of mineral
spirits into the lungs may produce serious damage leading to
bronchopneumonia that may be fatal within 24 h[ours] * * *.
    Rodriguez et al. [1991] reported a case incident where deaths in
3 crude oil tanker workers were reported as attributed to pulmonary
aspiration as evidenced by histopathology studies. The hypothesized
mechanism of deaths included the contributing factors of asphyxia by
toxic gases leading to loss of consciousness, traumatic injury and
aspiration.

A number of other cases are described in the NIOSH comment. The Panel
itself noted two aspiration fatalities in the period from 2003 to 2007,
one of which was related to a corrosion inhibitor, and the other to
sodium bisulfate (Document ID 0486, 0494 Tr. 212). Moreover,
the Panel's chair testified that her company includes aspiration hazard
warnings on all of its products (Document ID 494 Tr. 214-15).
Therefore, it is clear to OSHA that there are legitimate concerns about
aspiration in terms of both occupational injuries and fatalities, and
that aspiration hazards need to be included in the scope of the HCS.
Thus, OSHA included Chapter A.10, ``Aspiration Hazard,'' in Appendix A
in the proposed rule and has retained it in the final rule.
    With regard to the symbol, the application of the more severe
health hazard symbol to a Category 1 hazard category is consistent with
how the symbols are applied to all of the health hazards. Adopting the
exclamation mark in the U.S. for aspiration Category 1 would make the
HCS inconsistent with other countries' rules regarding aspiration
hazard, which would present difficulties for countries exporting to the
U.S., and potentially create inconsistencies in what workers see on
labels and SDSs. This would not be an effective communication approach
to aspiration hazards. Therefore, OSHA does not agree that the
exclamation mark should be permitted for Category 1 aspiration hazards.
In terms of presenting it to the UN Sub-committee as an issue, OSHA
will take that suggestion under advisement. However, industry
stakeholders are free to make this suggestion to the Sub-committee
themselves through submission of a paper.
    With regard to the contention that drowning in water could
conceivably be read as being covered by the aspiration hazard criteria,
OSHA assures stakeholders that drowning in water is not covered and
that the HCS will not be interpreted as addressing drowning in water as
an effect covered by the rule.
    Aspiration Hazard, Category 1, is included in the final rule as
proposed.
    Appendix B, Physical Hazards. Appendix B includes the criteria for
the physical hazards proposed to be covered by the HCS to be consistent
with the GHS. The current HCS covers these hazards, but the
definitions, while similar, are not the same as those included in the
GHS. The GHS based its physical hazard criteria on those incorporated
into the United Nations' Recommendations on the Transport of Dangerous
Goods. In the U.S., the Department of Transportation (DOT) has already
harmonized its definitions with the UN, and thus, with few exceptions,
the GHS. While OSHA's initial physical hazard definitions were
consistent with the DOT definitions at the time the current HCS was
promulgated, DOT's harmonization with the international requirements
resulted in the two agencies having different definitions. Thus the
U.S. has not been domestically harmonized for some years. Adopting the
same definitions in this rulemaking as DOT has in this rulemaking will
have

the additional benefit of accomplishing substantial domestic
harmonization.
    As with Appendix A and the health hazard criteria, OSHA edited
Chapter 2 of the GHS (``Physical Hazards'') to shorten the discussions
and focus only on the criteria in the proposed revisions. Decision
logics and hazard communication information are not included. As with
health hazards, OSHA tried to maintain the current scope of the HCS for
physical hazards in the proposal, as well as being as consistent as
possible with trading partners, particularly the European Union. One
exception may be flammable gases, where it appears that more flammable
gases will be covered by OSHA adopting Category 2 than are currently
covered by the HCS. OSHA is adopting all of the physical hazards in the
GHS.
    The one deviation from the approach adopted by the European Union
is in the proposed adoption of Categories 1 through 4 for flammable
liquids. The European system only addresses Categories 1 through 3. The
current HCS covers flammable liquids in Category 4, and exclusion of
this category would result in reduced protection, which OSHA does not
believe is appropriate. Thus Category 4 is included in the revised HCS.
    One edit that should be noted occurs in the criteria for
explosives. The GHS criteria currently use the term ``article'' in a
manner that is inconsistent with that term as used in the workplace in
the U.S. OSHA has changed the term to ``item'' in these criteria. This
modification was supported by stakeholders (See, e.g., Document ID
0362).
    While OSHA believes that harmonizing with DOT provides significant
benefits, there were some concerns regarding this approach that arose
in reviewing the physical hazard criteria. These concerns involved the
test methods referred to in the GHS criteria, which are based on issues
related to the packaging and volume in transportation. Packaging is
obviously a major concern in transport, and is used to address or
mitigate the risk of conveying certain types of chemicals. These
chemicals may or may not be present in the workplace in the same size
or type of packaging and the relevance of these factors in the test
methods are questionable in terms of workplace exposures. OSHA invited
comment on these factors, including comments on the appropriateness of
the criteria (including the test methods and references to packaging or
volume) when applied to the workplace, and any suggestions that
interested parties have to address these issues. Of particular interest
were criteria for self-reactive chemicals, organic peroxides, self-
heating chemicals, and explosives. Commenters indicated that the
criteria could be applied to the workplace (See, e.g., Document ID
0330, 0336, 0383, and 0405). Others specifically noted that
OSHA should maintain consistency with DOT (See, e.g., Document ID
0338, 0344, 0351, 0376, 0379, 0381, and 0392). For example,
the Industry Minerals Association--North America stated (Document ID
0379):

    The classification, labeling, handling and storage of chemicals
related to transport concerns should remain aligned with the
principles of HCS. OSHA should seek where possible to reduce
incompatibilities between HCS criteria and US DOT transportation
requirements.

    Accordingly, OSHA has decided to carry through these requirements
to the final rule as proposed. OSHA is satisfied that, in this respect,
the criteria proposed are appropriate.
    The Society of the Plastics Industry, Inc. (SPI) (Document ID
0392) contends that the requirements will not be possible to
implement for organic peroxides:

    The GHS would require that the SDS for organic peroxide include:
    (1) Recommended use of the chemical and restrictions on use;
    (2) Precautions for safe handling;
    (3) Conditions for safe storage, including any
incompatibilities, and
    (4) Appropriate engineering controls.
    Compliance with these requirements, which include principles
from the EU regulation for the Registration, Evaluation,
Authorisation and Restriction of Chemicals (REACH), presents a
particular concern for organic peroxide producers following
transportation and initial storage in the DOT-regulated transport
container. As written, compliance would present unreasonable
difficulties and appears to be infeasible for suppliers of these
chemicals. Customers are likely to handle and use these materials
under significantly different conditions once they remove the
organic peroxides from the packages in which they were transported.

SPI further recommends that OSHA require ``that labels and SDSs include
a generic statement of fact indicating that changes in risk and hazard
can occur when these self-reactive materials are moved from normal
transport and storage conditions into process settings, and that they
may require assessments by specialists.'' SPI also suggests that OSHA
should be harmonizing with DOT in this area.
    SPI indicates that these requirements for information on SDSs
originate with REACH requirements in Europe. In fact, OSHA has always
required such information on SDSs (with the exception of intended use
of the chemical, and restrictions on use), and these requirements
preceded REACH by many years--as did the negotiated text of the GHS. In
Sec.  1910.1200 (g)(2)(viii) and (ix) of the HCS promulgated in 1983,
the preparer of the MSDS is required to provide any generally
applicable precautions for safe handling and use, and any generally
applicable control measures such as engineering controls, which are
known to the chemical manufacturer, importer or employer. OSHA also
notes that the manual supplied and written by SPI: ``SAFETY AND
HANDLING OF ORGANIC PEROXIDES: A Guide'' (dated August 1999),
recommends that downstream users consult labels and MSDSs for handling
information (Document ID 0392). OSHA does not agree that the
SDS requirements in the NPRM, and the final rule, are infeasible or
even substantially different than what has been required by OSHA since
1983. The Agency does not agree that the suggested statement should be
required by OSHA regarding organic peroxides. Chemical manufacturers
and importers of organic peroxides are free to provide whatever advice
they deem appropriate in the supplementary information part of the
label, or on the SDS, to guide downstream users for appropriate
handling, as long as the advice does not conflict with the required
hazard communication information.
    With regard to harmonizing with DOT, the criteria in the final rule
are the criteria that DOT adopted from the UN Transport
recommendations. Therefore, OSHA is harmonizing with DOT through this
rulemaking.
    One commenter indicated that there was concern that criteria based
on transport classification may confuse workplace application, and
guidance would be needed (Document ID 0339):

    Concerns have been expressed that the criteria developed for
transport concerns, as stated in the GHS, express very specific
constraints, or ``worse case scenarios'', which can be confusing to
suppliers and users of chemicals who are reading the Safety Data
Sheets (SDSs)/labels, etc., without benefit of the context. PRR
believes this is an area in which OSHA could develop informational
materials to help chemical suppliers and users understand the
rationale behind physical hazard classifications.

OSHA will keep this suggestion in mind as guidance materials are
developed.
    Only minor editorial revisions have been made to Appendix B after
reviewing all of the comments received. While a great number of changes
were suggested by one commenter (Document ID 0353), most have
not been adopted, consistent with the discussion above on

the background for Appendixes A and B. This approach is to maintain
consistency with the GHS and DOT, as well as the EU.
    The modifications made in the final rule include changing metric
references to units used in the U.S., and modifying references to
documents incorporated by reference to make them consistent with OSHA's
requirements for such references. There are no technical changes to the
criteria. Therefore, Appendix B in the final rule is substantially the
same as proposed.
Classification Database
    One interesting comment that was submitted by a number of
respondents to the ANPR involved development of a classification
database (Document ID 0047, 0050, 0053, 0054, 0038, 0155,
0160, and 0165). Opinions as to who would develop and maintain such a
database varied (OSHA, U.S. industry, and an international body were
all mentioned). It appears that the European Union will be making such
a database available for compliance with its requirements, as have
Japan, Taiwan, South Korea, and New Zealand. Concerns have been raised
by stakeholders that classifications in these databases are different
for the same chemical. OSHA invited additional comment on this issue in
the NPRM (74 FR 50284, Sept. 30, 2009), and received a number of
responses.
    Many supported the concept of having such a database (Document ID
0328, 0329, 0330, 0335, 0336, 0339, 0341, 0352, 0365, 0366,
0379, 0383, 0389, 0408, 0410, and 0453). There were also various
comments about how a database might be done. Some thought OSHA should
do the classifications and maintain them online, or that the
classifications should be considered ``official'' (Document ID
0330, 0341, and 0453). Others were concerned about the
Agency's ability to develop and maintain a database (Document ID
0339), or said it should only be done if resources were
provided to maintain it (Document ID 0365). Alternatively,
resources could be provided for classifiers to help improve the quality
of their classifications (Document ID 0365).
    Others suggested that NIOSH could be tasked with developing and
maintaining the database (Document ID 0341 and 0408). NIOSH
commented that funding is not currently available, and that OSHA may
wish to partner with the EU database efforts (Document ID
0412). Additionally, NIOSH and another commenter (Document ID
0383) suggested alternatives to developing a database using
existing information such as the Department of Homeland Security's
database; using International Chemical Safety Cards that currently
cover 1,650 substances and are translated into many languages; or
adding GHS classifications to the National Library of Medicine,
including its Hazardous Substances Data Bank. NIOSH is also updating
its Pocket Guide to include GHS classifications.
    Another suggestion was to have the UN develop a database so there
is a globally harmonized list, and the Department of Labor could help
support it (Document ID 0328 and 0335). The National Fire
Protection Association (NFPA) (Document ID 0366) suggested
that its database of 2,500 chemicals could be useful in the transition.
Other commenters suggested that suppliers can provide classifications
to a central repository (Document ID 0352, 0408, and 0410),
but one commenter warned that if left to manufacturers, there would be
differences that would have to be resolved downstream (Document ID
0328). Another comment raised a concern that, while a common
database might be useful, it could also interfere with weight-of-
evidence determinations (Document ID 0379). However, such a
database could prove useful for substances, which would provide the
basis for mixture classifications (Document ID 0335).
    Other commenters did not support having a classification database
(Document ID 0324, 0344, 0351, 0370, and 0377), or indicated
that if OSHA were to develop a classification list, it should be non-
binding guidance, and include stakeholder input and global
accessibility (Document ID 0344, 0381, 0393, and 0405). Others
were concerned that a common database would create another unharmonized
list of classifications compared to lists in other countries (Document
ID 0344), and that manufacturers should have the
responsibility for classification (Document ID 0324 and 0405).
Also, a company could have valid data that contradicts a classification
assigned in a database, and should be allowed to use its own
information (Document ID 0351). There was also a concern that
such a list might impede progress by not using the best available data
(Document ID 0377). Another commenter argued that the database
would need to be internationally developed and maintained to be useful,
which would result in the elimination of national or regional lists
(Document ID 0376).
    OSHA is very interested in whether an international database of
classifications could be developed and maintained. It is not likely to
be feasible for OSHA to develop and maintain a U.S.-based database,
which, as some have noted, would be less useful than an internationally
harmonized approach that preempts countries and regions from developing
their own approaches. The subject has been raised and discussed in the
UN Sub-committee, and a correspondence group has been established to
explore the issue further. OSHA has volunteered to lead that group and
to help form a consensus position in the Sub-committee on options to
address this issue. In the meantime, some of the suggested sources can
provide extensive information to assist businesses with GHS
classifications, particularly small businesses with fewer technical
resources. The International Chemical Safety Cards--which are linked on
both OSHA and NIOSH Web pages--are one such resource. The OECD has also
established a global chemical portal that includes extensive