If your company is moving forward on the GHS MSDS to SDS conversion, you already know that chemicals will be reclassified and given new hazard definitions. The GHS hazard pictogram is one of the most important parts of the new GHS SDS format, and is based on the substance or mixture’s chemical hazard classification(s). But you may not know how these hazard classifications are given, what they represent, or even what the classes themselves are.
Even the definition of a hazardous chemical has been changed under the GHS. OSHA’s HCS defines a hazardous chemical as one that meets the definition of a health hazard class, a physical hazard class, or is an asphyxiant, combustible dust, pyrophoric gas, or a hazard not other classified. There is no way to exempt a chemical completely from being potentially hazardous, but chemicals with very low chances of being a health hazard are generally exempted from classifications.
Within health and physical classes there are many category classifications, but there are actually no testing requirements for those classifications. Rather than testing chemicals, manufacturers are left to identify hazards via scientific literature and other confirmed evidence of the substance or mixture’s potential hazards.
There are ten total health hazard classes and 16 total physical hazard classes. Many of these classes have subcategories, which can be found at https://www.osha.gov/FedReg_osha_pdf/FED20120326.pdf.
The health hazard classes are as follows:
1. Acute Toxicity
2. Skin Corrosion/Irritation
3. Serious Eye Damage/Eye Irritation
4. Respiratory or Skin Sensitization
5. Germ Cell Mutagenicity
6. Carcinogenicity
7. Reproductive Toxicity
8. Specific Target Organ Toxicity – Single Exposure, otherwise known as STOT-SE
9. Specific Target Toxicity – Repeated or Prolonged Exposure, otherwise known as STOT-RE
10. Aspiration Hazard
The physical hazard classes are as follows:
1. Explosives
2. Flammable Gases
3. Flammable Aerosols
4. Oxidizing Gases
5. Gases Under Pressure
6. Flammable Liquids
7. Flammable Solids
8. Self-Reactive Chemicals
9. Pyrophoric Liquids
10. Pyrophoric Solids
11. Self-Heating Chemicals
12. Chemicals Which, in Contact with Water, Emit Flammable Gases
13. Oxidizing Liquids
14. Oxidizing Solids
15. Organic Peroxides
16. Corrosive to Metals
Many of these GHS hazard classifications have numerical subcategories, within which one corresponds to the most dangerous category and the higher numbers represent diminishing levels of potential chemical hazards.
The assignment of a hazardous chemical to a GHS chemical hazard class is carried out in a series of steps. Manufacturers themselves are responsible for determining if a chemical or a component is hazardous, so it is important to follow these steps as closely as possible. They are as follows:
1. Identifying all relevant data as to the known hazards of the chemical
2. Review that data to be certain as to what hazards are associated with the chemical
3. Using the chemical’s physical, health, and other hazards, determine if the chemical is hazardous
4. Identify the hazard classes that apply to each chemical individually
5. If applicable, identify the hazard category within the overall hazard class for the chemical being classified.
This last step is very important to the classification process. It is not enough simply to realize that a chemical poses a physical or health hazard – those who use the chemical will need to know the severity to which that hazard exists. The information you can derive from defining hazard classifications for each of your chemicals will be used on SDSs and GHS chemical labels, so attention to detail is a crucial part of the classification process.
The new method of hazard communications may seem complicated, but when you understand the process it really becomes fairly simple. GHS hazard classification is nothing more than identifying a product’s hazards and assigning it to the corresponding hazard class for the safety of all who will use that product in the future.
