The Shift from Rev 3 to Rev 7
The 2024 final rule updating the OSHA Hazard Communication Standard (HCS) marks a significant regulatory shift, moving the United States from GHS Revision 3 (2009) to primarily GHS Revision 7 (2017). While this alignment is designed to facilitate international trade and improve worker safety, it introduces complex reclassifications that employers must master before the November 20, 2026 compliance deadline.
Safety managers must adopt a "converter" mindset, understanding how familiar hazard classes from 2012 have been split, renamed, or expanded in the new standard. Failure to recognize these changes will lead to incorrect labeling and inadequate training.
Key Hazard Class Conversions
1. Flammable Gases: The Split
Impact: Construction sites using acetylene or specialized welding gases must ensure their training specifically addresses the "Category 1A" designation, highlighting the extreme instability of these substances.
2. Aerosols: Beyond Flammability
Impact: Many common construction products—silicone sprays, cleaners, and lubricants—that were previously considered "safe" (non-flammable) will now carry an Aerosol classification. Workers must be trained that "Category 3" still poses a rupture risk under heat.