U.S. OSHA Amends Hazard Communication Standard to Align with GHS Rev. 7

On May 20, 2024, the Occupational Safety and Health Administration (OSHA) amended the Hazard Communication Standard (HCS) to align with the 7th Revised Edition of the UN's Globally Harmonized System of Classification and Labelling of Chemicals (GHS). The amendment includes elements from the 8th Revised Edition of the GHS and retains certain U.S.-specific requirements. The regulation takes effect on July 19, 2024, with compliance required by January 19, 2026, and for mixtures by July 19, 2027.

I. Key Revisions to Health Risks

1. Acute Toxicity

If a chemical is found to be corrosive to the respiratory tract and potentially lethal, it must be labeled for acute toxicity with the appropriate pictogram and hazard statement. Additionally, it should be marked as corrosive, including the statement "Corrosive to the respiratory tract" and the corrosion pictogram.

If acute toxicity testing shows a chemical is corrosive to the respiratory tract but not fatally so, it should be classified under Specific Target Organ Toxicity for single exposure (STOT SE 1/2, excluding Category 3). It also requires labeling with the hazard statement "Corrosive to the respiratory tract if inhaled," and the corresponding corrosion pictogram, differentiating it from general acute toxicity classifications.

If a chemical doesn't meet STOT SE criteria but is classified for skin corrosion/irritation or serious eye damage/eye irritation, assess its potential as a respiratory corrosive. Accordingly, add the hazard statement "Corrosive to the respiratory tract."

These revisions aim to ensure that information about corrosive hazards is clearly communicated to downstream users, enabling workers and others to prevent accidents involving gas, vapor, or mist leaks.

2. Germ Cell Mutagenicity

The revised definition of germ cell mutagenicity describes it as heritable genetic changes in germ cells caused by exposure to certain substances or mixtures, including heritable structure and numerical chromosome aberrations.

3. The hazard classification system has been refined to include human experiential data in assessments of acute toxicity.

II. Key Revisions to Physical Hazards

1. Pyrophoric and chemically unstable gases are now placed in Flammable Gases Hazard Class 1A, with a newly established Class 1B extending coverage to nearly all flammable gases.

2. The classification for desensitized explosives has been updated to align with UN GHS Rev. 8, introducing four subcategories.

3. The differentiation between aerosols and pressurized gases has been enhanced. The term "flammable aerosols" has been updated to "aerosols." These are now categorized into three classes based on combustion properties and heat values, with non-flammable aerosols classified as Class 3.

4. The latest UN GHS Rev. 8 includes chemicals under pressure in sub-classes 1-3.

III. Key Revisions to Label Requirements

OSHA endorses standardized small container labeling to clarify chemical hazards and better protect workers. For containers up to 100 mL, abbreviated labels may be used if tags and fold-out labels prove impractical. These should include the product identifier, pictogram, signal word, manufacturer’s name, and phone number, with full labels on the external packaging. For very small packages of no more than 3 mL, only the product identifier is needed if standard labels would impede container use.

IV. Essential Updates to Safety Data Sheets (SDS)

Section 2 of the Safety Data Sheet (SDS) details hazard information for the chemical, including risks from physical changes during normal use. Consistent with Health Canada's WHMIS, Section 3 allows the confidentiality of concentration ranges as trade secrets, provided they comply with predefined categories (A-M). If a component's concentration straddles two ranges, both adjacent intervals may be used.

Section 8 should list exposure limits for individual components in mixtures, such as PEL and TLV. Section 9 now includes additional entries on physical and chemical properties like particle characteristics. In alignment with UN GHS Rev. 7, Section 11 should detail interaction effects if relevant and accessible. If specific chemical data is unavailable, the use of alternative information and its derivation method must be stated.

V. Additional Significant Modifications

1. This update clarifies that nuisance particulates are exempt when manufacturers or importers determine they pose no physical hazard, health hazard, or other hazards covered under the HCS.

2. The definition of combustible dust has been added, with updates to the related hazard statements.

The revised HCS addresses previous implementation issues and aligns with federal and international standards. Canada, for instance, has updated its Hazardous Products Regulations to conform to UN GHS Rev. 7 and has adopted elements from Rev. 8. Manufacturers and importers must provide detailed data on the properties and risks of their chemicals. Employers using hazardous chemicals must implement a hazard communication strategy, informing employees about risks and protection measures. For substances, employers need to update labels, hazard programs, and offer new hazard training by July 20, 2026. For mixtures, these updates should be completed by January 19, 2028.

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Further Information 

Hazard Communication Standard