Key Principles and Assumptions

• The core framework of HCS remains unchanged: Chemical manufacturers and importers must continue to provide information on the identities and hazards of chemicals they produce or import.

• Employers with hazardous chemicals must maintain a hazard communication program, inform employees about hazards, and provide training on protective measures.

Purpose of the 2024 Final Rule

The update aims to:

• Enhance worker protection through clearer regulatory requirements.

• Introduce new hazard classes and categories.

• Streamline precautionary statements.

• Facilitate international trade by increasing alignment with global standards.

Major Updates in the Final Rule

1. Hazard Classification Health Hazards (Appendix A)

• Revised definitions: For example, the definition for germ cell mutagenicity has been updated.

• Skin corrosion/irritation: Now aligns with GHS Revision 8, promoting alternative test methods.

• Acute toxicity: Clarifies the use of human data.

• Serious eye damage/irritation: Updates reflect GHS Revision 7 and clarify pH use.

Physical Hazards (Appendix B)

• Flammable gases: New subcategory 1b for gases with low burning velocity or high flammability limit. Pyrophoric and unstable gases are now under Category 1A.

• Aerosols: Better differentiation between aerosols and gases under pressure. Aerosols are now classified into three categories based on flammability and heat of combustion.

• Chemicals under pressure: A new hazard category for liquids or solids pressurized with gas (other than aerosols).

• Desensitized explosives: New chapter for explosives that must be wetted or diluted to reduce explosive properties.

2. Labeling Updates

• Flexibility for updating labels: Manufacturers, importers, and distributors may opt not to relabel containers released for shipment, provided a label is supplied for each container.

• Hazards Not Otherwise Classified (HNOC): The exclamation pictogram is now permitted for HNOCs.

• Bulk shipment labels: Can be placed on the container, transmitted with shipping papers, or sent electronically for immediate access at the receiving end.

• Small package labeling:

  • Containers ≤100ml: Abbreviated labeling allowed on the immediate container, with the full label on the outer package.

  • Containers ≤3ml: Only the product identifier is required if labeling interferes with use.

• DOT pictograms: HCS pictograms may now appear alongside DOT placards.

3. Safety Data Sheet (SDS) Updates

• Section 2: Clarifies hazard information, including hazards from changes in chemical form and hazards from chemical reaction products during known or anticipated uses.

• Section 3: Allows trade secret concentration ranges using prescriptive ranges.

• Section 8: Clarifies inclusion of exposure limits (PEL, TLV, etc.) for individual ingredients.

• Section 9: Now requires inclusion of particle characteristics like size.

• Section 11: Inclusion of interactive effects and use of SAR/QSAR/read-across methods.

4. Compliance Dates

A transition period runs from May 20, 2024, until the final compliance dates. During this period, compliance with either the new or previous standard (or both) is permitted.

5. Guidance Materials

OSHA has released updated guidance documents, including:

• Redline/strikeout versions of the rule.

• Label and SDS fact sheets/quick cards.

• Frequently Asked Questions (FAQs).

Conclusion

The 2024 HCS update marks a substantial step towards global harmonization and improved worker safety. Employers, manufacturers, and distributors should review the new requirements, update their hazard communication programs, and take advantage of OSHA’s guidance materials to ensure compliance by the relevant deadlines.