The U.S. Occupational Safety and Health Administration (OSHA) issued a final rule on May 20, 2024, that amends the Hazard Communication Standard (HCS) to conform to the Globally Harmonized System of Classification and Labeling of Chemicals (GHS), primarily Revision 7 (Rev 7), address issues that arose during the implementation of the 2012 update to the HCS, and provide better alignment with other U.S. agencies and international trading partners while enhancing the effectiveness of the standard. 89 Fed. Reg. 44144. OSHA states that, consistent with Executive Order 13563 and the Regulatory Flexibility Act, which call for assessment and, where appropriate, modification and improvement of existing rules, OSHA has reviewed the existing HCS. OSHA states that it determined that the revisions in the final rule “will enhance the effectiveness of the HCS by ensuring employees are appropriately apprised of the chemical hazards to which they may be exposed, thus reducing the incidence of chemical-related occupational illnesses and injuries.” The modifications to the HCS include revised criteria for classification of certain health and physical hazards, revised provisions for updating labels, new labeling provisions for small containers, new provisions related to trade secrets, technical amendments related to the contents of safety data sheets (SDS), and related revisions to definitions of terms used in the standard. The final rule will be effective July 19, 2024. The incorporation by reference of certain publications listed in this final rule is approved by the Director of the Federal Register as of July 19, 2024. The incorporation by reference of certain other publications listed in the rule was approved by the Director as of July 15, 2019.

Section XIV: Summary and Explanation of the Final Rule is organized by paragraph of regulatory text affected by the final rule, followed by the appendices to the regulatory text. OSHA has posted questions and answers and a side-by-side comparison on its web page for the final rule. According to the final rule, OSHA will issue guidance materials and respond to inquiries on any aspects of the HCS for which stakeholders request information or clarification.

Discussion of Incorporation by Reference

The final rule updates OSHA’s incorporation by reference section, 29 C.F.R. Section 1910.6, to include certain national and international consensus standards. The final rule states that where OSHA has updated consensus standards, “OSHA does not intend to require chemicals already classified using an earlier version of a consensus standard to be reclassified and has retained earlier versions of the consensus standards in the text of the standard where relevant to avoid suggesting retesting is necessary (for the U.N. Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria, this is reflected in the use of a generic citation where either Rev. 4 or Rev. 6 is acceptable, and a specific citation to Rev. 6 where there is new material included and only Rev. 6 is acceptable to use).” According to the final rule, “OSHA believes that requiring the reclassification of chemicals based on updated test methods could result in unnecessary economic impacts and create unnecessary confusion for stakeholders.”

Discussion of Regulatory Text

Purpose

Paragraph (a)(1) of the HCS states that ‘‘[t]he purpose of this section is to ensure that the hazards of all chemicals produced or imported are classified, and that information concerning the classified hazards is transmitted to employers and employees.’’ OSHA notes that in the 2012 HCS, paragraph (a)(1) explains that the requirements of the HCS were intended to be consistent with Rev 3. Revisions included in the final rule primarily serve to align the HCS with Rev 7, with the exception of selected provisions that either align with Rev 8 or do not relate to the GHS. OSHA is therefore amending paragraph (a)(1) to update the reference to the GHS to ‘‘Revision 7,’’ replacing ‘‘Revision 3.’’ In addition, OSHA is inserting ‘‘primarily’’ before ‘‘Revision’’ “because the agency is finalizing some of the proposed changes from Rev. 8.”

Scope and Application

Paragraph (b) of the HCS specifies the scope and application of the rule, including the chemicals that are (and are not) covered by the standard. The final rule modifies paragraph (b)(6)(x) of the 2012 HCS, which excludes nuisance particulates from the HCS under certain circumstances. OSHA states that it is modifying paragraph (b)(6)(x) to clarify that nuisance particulates are excluded from the scope of the HCS “when the chemical manufacturer or importer can establish they do not pose any physical hazard, health hazard, or other hazards covered under the HCS.”

Definitions

Paragraph (c) of the HCS provides definitions for terms used throughout the rest of the HCS. According to OSHA, paragraph (c) is designed to increase stakeholders’ comprehension of requirements under the HCS and improve compliance. OSHA notes that many of the definitions in paragraph (c) align with the GHS, but some are unique to the HCS. The final rule codifies the definitions of bulk shipment, exposure or exposed, gas, hazardous chemical, immediate outer package, physician or other licensed health care professional (PLHCP), released for shipment, and solid as proposed. In addition, OSHA is eliminating the definition of pyrophoric gas as proposed. OSHA is codifying the definitions of combustible dust, liquid, and physical hazard with changes from the notice of proposed rulemaking (NPRM) based on comments.

Hazard Classification

Paragraph (d)(1) of the HCS outlines the requirements for chemical manufacturers and importers to evaluate the hazards of chemicals that are in the workplace or being imported to determine the hazard classes, and where appropriate, the category of each class that applies to the chemical being classified. OSHA states that it is modifying the proposed language to articulate more clearly its intent for the scope of this requirement, as well as to distinguish better between hazards associated with the chemical as shipped and hazards associated with downstream use. Specifically, the final rule deletes the phrase “under normal conditions of use and foreseeable emergencies.” The final rule adds at the end of (d)(1) the phrase “The hazard classification shall include any hazards associated with the chemical’s intrinsic properties including:” and then adds two subparagraphs, (d)(1)(i) and (d)(1)(ii). New paragraph (d)(1)(i) reads “a change in the chemical’s physical form and;” and new paragraph (d)(1)(ii) reads “chemical reaction products associated with known or reasonably anticipated uses or applications.” The final rule also amends the language in paragraph (f)(1) to clarify that hazards identified and classified under new paragraph (d)(1)(ii) will not be required to appear on a product’s label.

OSHA notes that changes in Appendix D clarify that hazards identified and classified under both paragraphs (d)(1)(i) and (d)(1)(ii) must be included in Section 2 of the product’s SDS. According to the final rule, “OSHA considers the language, as finalized, to be a rephrasing of the language proposed in the NPRM to more clearly articulate OSHA’s intent and not a substantive change from what OSHA originally intended in the NPRM or the preexisting requirement to incorporate downstream uses.” The final rule states that the rest of the section therefore still relies on previous guidance and statements OSHA made regarding “normal conditions of use and foreseeable emergencies” to support the language OSHA is codifying.

Written Hazard Communication Program

Paragraph (e) of the HCS provides specific requirements for chemical manufacturers, importers, distributors, or employers to develop, implement, and maintain a written hazard communication program. The final rule notes that paragraph (e)(4) requires employers to make their written hazard communication program available, upon request, to employees, their designated representatives, the Assistant Secretary, and the Director of the National Institute for Occupational Safety and Health (NIOSH). The final rule contains one change to correct a reference in paragraph (e)(4) that erroneously referred to 29 C.F.R. Section 1910.20 instead of 29 C.F.R. Section 1910.1020 when specifying when and how employers must make the written hazard communication program available.

Labels and Other Forms of Warning

Paragraph (f) of the HCS provides requirements for labeling. In the NPRM, OSHA stated that it proposed to modify paragraphs (f)(1), (f)(5), and (f)(11), and also proposed a new paragraph (f)(12). Paragraph (f)(1) of the HCS, Labels on shipped containers, specifies what information is required on shipped containers of hazardous chemicals and also provides that hazards not otherwise classified (HNOC) do not have to be addressed on these containers. OSHA proposed to revise paragraph (f)(1) to provide that, in addition to HNOCs, hazards resulting from a reaction with other chemicals under normal conditions of use do not have to be addressed on shipped containers. According to OSHA, it “believed this information was not appropriate on containers because it might confuse users about the immediate hazards associated with the chemical in the container.” OSHA notes that because it believed information on hazards resulting from a reaction with other chemicals under normal conditions of use is important for downstream users, it did not propose to change the existing requirements for these hazards to be indicated on SDSs (under Appendix D) and addressed in worker training where applicable (under paragraph (h)). OSHA states that it also proposed to add the word “distributor” to the third sentence of paragraph (f)(1) to make it consistent with the first sentence.

OSHA also proposed to add a new paragraph, (f)(1)(vii), to require that the label include the date a chemical is released for shipment. OSHA notes that it proposed this change in conjunction with changes in paragraph (f)(11) related to relabeling of containers that are released for shipment but have not yet been shipped. OSHA states that it believed that providing the date a chemical is released for shipment on the label would allow manufacturers and distributors to determine more easily their obligations under paragraph (f)(11) when new hazard information becomes available. According to the final rule, OSHA “finds compelling the arguments that the date a chemical was released for shipment is not needed on labels because this information is already available through other means and that the addition of the date could cause confusion for downstream users due to other (non-HCS) date requirements on the label.”

Paragraph (f)(5) specifies label requirements that apply to the transport of hazardous chemicals from workplace to workplace. OSHA notes that in the NPRM, it proposed to add the heading “Transportation” to this paragraph. OSHA received no comments on the proposed new paragraph heading and is codifying the heading “Transportation” as proposed.

OSHA proposed to add two new subparagraphs to (f)(5) specifying requirements related to the transportation of hazardous chemicals. New paragraph (f)(5)(ii) would address the transportation of bulk shipments of hazardous chemicals (i.e., in tanker trucks, rail cars, or intermodal containers). The proposed paragraph would specify that labels for bulk shipments of hazardous chemicals may either be on the immediate container or may be transmitted with shipping papers, bills of lading, or by other technological or electronic means so that the information is immediately available in print to workers on the receiving end of the shipment. The final rule codifies (f)(5)(ii) with revisions to clarify that the label may be electronically transmitted only with agreement from the receiving end.

In the NPRM, OSHA proposed to: (1) delete the language currently in paragraph C.2.3.3 from Appendix C and (2) add new paragraph (f)(5)(iii) to provide that where a U.S. Department of Transportation (DOT) pictogram appears on a shipped container, the Appendix C pictogram for the same hazard is allowed, but is not required, on the HCS label. The final rule codifies (f)(5)(iii) as proposed with the exception of removing the phrase “the label for” where it referred to DOT requirements.

OSHA, in the NPRM, proposed to add a sentence to paragraph (f)(11) providing that chemicals that have been released for shipment and are awaiting future distribution need not be relabeled; the chemical manufacturer or importer must provide the updated label for each individual container with each shipment, however. According to OSHA, the purpose of these changes was to account for the long distribution cycles of some products and the potential hazards workers could face in relabeling the immediate containers of hazardous chemicals that have already been prepared for shipment. OSHA states that it is modifying the proposed text “to make clear that for chemicals that have been released for shipment and are awaiting further distribution, the chemical manufacturer, importer, or distributor has the option not to relabel after learning significant new hazard information.” OSHA notes that if they choose to take that option, they must produce updated labels for each container and send those labels with the shipment for the downstream users. The final rule revises the title of paragraph (f)(11) from “‘Release for Shipment” to “Label Updates” to reflect better the true purpose of the provision: providing requirements for updating information on labels.

The NPRM proposes a new paragraph, (f)(12), to address small container labeling. The 2012 HCS requires that all shipped containers be labeled with the information specified in paragraph (f)(1). OSHA states that through letters of interpretation (LOI) and the HCS compliance directive, it “provided a practical accommodation to address situations where it is infeasible to provide all HCS-required label information directly on small containers through the use of pullout labels, fold-back labels, or tags.” OSHA proposed to incorporate this accommodation into the HCS in new paragraph (f)(12). OSHA proposed that all of the new small container labeling provisions apply only where the chemical manufacturer, importer, or distributor can demonstrate that it is not feasible to use pull-out labels, fold-back labels, or tags containing the full label information required by paragraph (f)(1). The final rule amends paragraph (f)(12) as proposed.

SDSs

Paragraph (g) specifies the requirements for chemical manufacturers and importers to obtain or develop an SDS for each hazardous chemical in the workplace. The final rule revises paragraphs (g)(2), which identifies what information must be included on an SDS, and (g)(10), which addresses the form and storage of SDSs, and corrects erroneous references to material safety data sheets in (g)(7).

Trade Secrets

Paragraph (i) of the HCS describes certain conditions under which a chemical manufacturer, importer, or employer may withhold the specific chemical identity, other specific identification of a hazardous chemical, or the exact percentage of the substance in a mixture from the SDS. To align with Canada’s Workplace Hazardous Materials Information System (WHMIS), OSHA proposed to allow manufacturers, importers, and employers to withhold a chemical’s concentration range as a trade secret, add language specifying that it is Section 3 of the SDS from which trade secret information may be withheld, and require the use of prescriptive concentration ranges in lieu of the actual concentration or concentration range whenever the actual concentration or concentration range is claimed as a trade secret. OSHA states that after considering all comments on the proposed requirement to use prescribed ranges that align with those in use by Health Canada, it “has decided to finalize the requirement to utilize prescribed concentration ranges when claiming exact concentration as proposed, with the exception that OSHA is adding a new paragraph (i)(1)(vi).” The new provision allows the use of narrower ranges than those prescribed in (i)(1)(iv) and (i)(1)(v), “meaning that the range must be fully within the bounds of a prescribed range listed in (i)(1)(iv) or fully within the bounds of a combination of ranges allowed by (i)(1)(v).”

The concentration or concentration ranges are noted as follows:

(A) From 0.1% to 1%;

(B) From 0.5% to 1.5%;

(C) From 1% to 5%;

(D) From 3% to 7%;

(E) From 5% to 10%;

(F) From 7% to 13%;

(G) From 10% to 30%;

(H) From 15% to 40%;

(I) From 30% to 60%;

(J) From 45% to 70%;

(K) From 60% to 80%;

(L) From 65% to 85%; and

(M) From 80% to 100%.

Dates

Paragraph (j) of the HCS specifies the dates by which compliance with the updated provisions of the HCS is required. The final rule modifies the previous dates in paragraph (j), which pertained to implementation of the 2012 update to the HCS and have all passed. OSHA states that it modified the compliance dates in the final rule from those proposed in the NPRM to address stakeholders’ concerns that the proposed dates did not provide sufficient time for chemical manufacturers, importers, and distributors to comply. The final rule codifies paragraph (j) with the following modifications:

• Chemical manufacturers, importers, and distributors evaluating substances are required to comply with all modified provisions of the HCS no later than January 19, 2026 (paragraph (j)(2)(i));
• Those entities evaluating mixtures must comply with all modified provisions no later than July 19, 2027 (paragraph (j)(3)(i));
• New paragraphs (j)(2)(ii) and (j)(3)(ii) require employers to update any alternative workplace labeling under paragraph (f)(6), update the hazard communication program required by paragraph (h)(1), and provide any additional employee training in accordance with paragraph (h)(3) for newly identified hazards no later than July 20, 2026, for substances and January 19, 2028, for mixtures; and
• New paragraph (j)(4) provides that chemical manufacturers, importers, distributors, and employers may comply with either the previous version of the HCS, the version codified in this rule, or both during the transition period.

Appendix A

Appendix A addresses the health hazards covered by the HCS, including classification criteria consistent with the GHS. The NPRM proposes to update Appendix A in several respects. The final rule discusses the final changes to Appendix A, OSHA’s review of the comments and testimony received on the proposed changes to Appendix A, and its response to those comments and testimony in order of revisions to specific health hazards in Appendix A, followed by general changes to definitions and terminology, clarification of mandatory requirements, and corrections. All mandatory health hazard criteria are revised, but the most significant changes are consideration for corrosion to the respiratory tract if data are available based on acute inhalation toxicity, the inclusion of classification based on in vitro/ex vivo data for skin irritation or skin corrosion, and the use of in vitro alternatives for classification of serious eye damage/eye irritation.

Appendix B

Appendix B addresses the mandatory physical hazards covered by the HCS, including classification criteria consistent with the GHS. OSHA notes that it proposed several substantive updates to Appendix B, including the addition of a new hazard class (desensitized explosives) and several new hazard categories (splitting Category 1 into 1A and 1B and further subdividing Category 1A into flammable gases, chemically unstable gases, and pyrophoric gases in the Flammable Gases class, as well as nonflammable aerosols in the Aerosols class), revisions to the consensus standards and testing methods referenced in Appendix B, and clarifications based on implementation issues that arose from the 2012 HCS.

OSHA states that it proposed to include the new hazard class and hazard categories because, since the HCS aligned with the GHS in 2012, new physical hazard classes or hazard categories have been added to Rev 7 that better identify and communicate hazard information to downstream workers. OSHA proposed to adopt those additions to maintain alignment with the GHS. According to the final rule, OSHA preliminarily determined that the addition of these specific hazard classes and categories would better differentiate between the hazards and better communicate hazards on labels for downstream users by using more targeted hazard statements, precautionary statements, and pictograms.

To maintain alignment with Rev 7, OSHA also proposed several updates to references to consensus standards and testing methods. Although the HCS does not require testing and permits classifiers to use data from literature or experience for classification purposes, OSHA states that it proposed to update consensus standards and testing methods referenced in Appendix B in accordance with Rev 7 to ensure that data considered for classification incorporate updated scientific principles. OSHA notes that it “is not, however, implying that data obtained from the older methods would no longer be valid or that classifiers would need to retest or reclassify chemicals due to these updated methods.” OSHA proposed certain corrections and clarifications to Appendix B to address previous inadvertent omissions from the GHS or the HCS; changes made to the GHS to improve clarity or technical accuracy; and how some hazard classes should be evaluated in light of the addition of new hazard classes in the GHS. OSHA proposed these changes to align the HCS with the GHS while improving the classification and communication of hazards and maintaining or enhancing worker safety and health. According to the final rule, OSHA has determined that primarily aligning the HCS with Rev 7 will not only improve safety and health but will also ease compliance burdens for U.S. stakeholders that must also comply with international requirements for hazard classification and communication.

Appendix C

Appendix C includes requirements and instructions for the allocation of label elements. Paragraph (f)(2) of the HCS requires the chemical manufacturer, importer, or distributor to ensure that the information provided on the label is in accordance with Appendix C. Appendix C provides hazard statements, signal words, pictograms, and precautionary statements for all four essential aspects of hazardous chemical management (prevention, response, storage, and disposal), as well as general labeling instructions.

OSHA states that it proposed several updates to Appendix C to improve communication of hazard information on labels. OSHA proposed these changes to address labeling requirements for the new hazard classes and categories in Appendix B (physical hazards); align the HCS with Rev 7; and improve alignment of the HCS with other federal agencies and Health Canada’s labeling requirements in furtherance of the goals of the U.S.-Canada Regulatory Cooperation Council (RCC).

OSHA notes that in the 2021 NPRM, it proposed several changes based on new precautionary statements and instructions in Rev 7. Additionally, since 2012, OSHA has continued to work with other federal agencies on crosscutting labeling issues. OSHA proposed some updates to Appendix C to align with DOT labeling regulations and also proposed updates to Appendix C based on its cooperation with Health Canada under the RCC. According to the final rule, the RCC was reaffirmed through a memorandum of understanding signed in June 2018, with the expectation of aligning efforts for international trade requirements between the two countries.

OSHA states that overall, it anticipated that the proposed changes to Appendix C would provide improved communication of hazard information and greater detail and clarity for downstream users that would maintain or enhance the safety and health of workers. OSHA also expected the updates to align the HCS more consistently with other federal and international regulations, “thereby easing compliance burdens for U.S. stakeholders that must also comply with those requirements.”

Appendix D

Appendix D provides specific requirements for what information chemical manufacturers, distributors, importers, and employers must provide on the SDS, including rules regarding specific headings, subheadings, and information to be contained under each subheading. OSHA states that the information specified as mandatory in Appendix D is the minimum required information on the SDS, but “an SDS may include additional information as long as it does not contradict or undermine the required SDS elements.” In the NPRM, OSHA proposed several changes in Appendix D to align with Rev 7, clarify existing requirements about which stakeholders have expressed confusion, and ensure consistency with updated scientific principles. This includes a clarification that while the SDS must contain all the required information, the information is not required to appear in a specific order within each section. OSHA notes that the inclusion, in Section 1 – Identification, of a U.S. address and U.S. telephone number is based on previously existing requirements and provided for clarification purposes.

OSHA includes discussions of elements in the NPRM on which it requested comments that included a potential timeframe for future updates and electronic labeling. OSHA concludes that “…it is more prudent to only update the HCS when significant changes have occurred to the GHS that require realignment to improve worker safety.” In addition, OSHA does not propose any new changes related to electronic labeling at this time. The agency does acknowledge that is will consider the comments received “…in future discussions at the UN and in future HCS revisions.”

Commentary

In some respects, the long-awaited final rule contains few surprises. The alignment with Rev 7 and elements of Rev 8 appear to be nearly identical to the 2021 NPRM. The changes to the regulatory text and appendices provide a much-needed update to the HCS that aligns OSHA’s approach with that of our key trading partners. While the final rule discusses extensively key points raised during the NPRM process, the organizational integrity of the rule makes it challenging to discern what was included, what was excluded, and what was revised. In short, the read is a hard slog.

OSHA seeks to clarify in the final rule the phrase “under normal conditions of use and foreseeable emergencies” text in paragraph (d)(1). OSHA acknowledges clarification was “necessary because there had been some confusion about whether chemical reactions that occur during normal conditions of use must be considered during classification and whether this information should be placed on the label and/or the SDS…” Readers can parse the final rule and determine for themselves whether the clarification achieves what OSHA believes it does, namely “ensure that workers have the information necessary to protect themselves from the hazards posed by chemicals to which they are occupationally exposed.” Much needed guidance and practical examples are promised, but by when is unclear.

The addition of the “released for shipment” statement on the label was a proposal on which many commented. OSHA includes the concept and a new definition in the final rule but declines to require the statement on the label. This is an accommodation for relabeling under specific conditions.

OSHA’s disposition of its proposal relating to “bulk shipments” is interesting. OSHA notes in the final rule that it is purposefully disconnecting itself from the common terminology of “bulk packaging” because the term would not adequately support the labeling requirements. OSHA instead uses this term to address when the container used for shipping is the immediate container and offers alternative approaches to labeling. This clarification and new terminology, OSHA hopes, will provide a clearer path forward for stakeholders in meeting the new requirements.

The inclusion of small container labeling is a significant benefit and aligns HCS with the UN GHS approach and with OSHA’s own LOIs. OSHA notes that these “…labeling provisions apply only where the chemical manufacturer, importer, or distributor can demonstrate that it is not feasible to use pull-out labels, fold-back labels, or tags containing the full label information required by paragraph (f)(1).” It is not entirely clear what that burden of proof is, and additional guidance from OSHA is expected.

The final rule includes significant discussion on costs and timing considerations for the application of these changes to impacted parties. OSHA rarely agrees with the estimates commenters provided during the comment period for the NPRM, and this rule is no exception. Several noted that anytime there are changes to Appendix C (labels) and/or Appendix D (SDS content), the impact is significant. The final rule includes new and revised language on nearly every element within Appendix C, which in turn, impacts content on the SDS. Similarly, changes to Appendix D will require updates to every SDS currently available. OSHA believes its staggered compliance dates will accommodate implementation. We are not as certain. The implementation of HCS 2012 also included staggered compliance dates, but implementation was complicated by supply chain issues and OSHA was forced to accommodate by extending deadlines. If past is prologue, we can expect much of the same will occur in implementing HCS 2024.