Hazard Communication: Using GHS to Improve Health and Safety
How the Globally Harmonized System (GHS) improves hazard communication.
- By Tom Burgess
- Feb 26, 2025
I once had an experience working with a manufacturing operation that included painting processes for the main production line and a small spray-painting area in the repair section. The facility regularly handled hundreds of gallons of solvent-based paint and had a solid understanding of manufacturing controls. Despite this, when I reviewed their repair area, some of the paint had different formulations, which included components that presented an increased sensitization and toxicity hazard.
What quickly stood out to me in differentiating the different hazards of the solvents were the signal words and hazard statements on the label and in the Safety Data Sheet (SDS). While those of us who work with chemicals are accustomed to warning labels and SDSs, I have found that many people do not recognize that the specific terms used are defined in the Globally Harmonized System of Classification and Labeling of Chemicals (GHS), and understanding them can be very helpful for hazard recognition.
By comparing the ratings on the label and the Safety Data Sheet (SDS), I was able to identify the different and increased hazards of the paints used in the repair area. I was then in a better position to work with the facility to ensure that the appropriate communications and hierarchy of controls were in place.
Danger and Warning
The use of the terms “danger” and “warning” are defined in GHS. When looking at container labels, the use of the term “danger” was the first indication of hazard potential. Danger is usxed to indicate a higher hazard category for the particular health or physical hazards of the chemical. This term combined with a warning for sensitivity quickly indicated that the chemical was in a high sensitizer hazard category. The term “warning” indicates a lower hazard category, and no signal word can indicate a low hazard category or that the chemical does not have a hazard defined in the GHS criteria.
Pictograms and Precautionary Statements
GHS can help us quickly identify hazards and their severity with pictograms and hazard statements. Pictograms are used when chemical hazards meet the GHS hazard criteria. The health hazard pictogram combined with a danger warning statement on the label was a pretty good indication that this material could present a significant risk.
Precautionary statements, the written hazard information and warnings on the label, are also well defined in the GHS system, which is another way that it helps assess the type and level of hazard. Different manufacturers and suppliers following GHS will have similar information on their labels and SDS. So, a reasonable comparison of the hazards is still possible when there are different solvents from different suppliers.
Occupational Safety and Health Administration, U.S. Department of Labor, Comparison of NFPA 704 and HazCom 2012 Labels
The danger warnings and pictograms are shown in the OSHA Quick Card example label, so we already know there are some significant hazards. The warning statements are specified in GHS to correspond to the hazard category. The label may not list the category, but that will be in the SDS. In our example, two Category 1 hazards and two Category 3 hazards are listed.
The precautionary statements and hazard categories on the label and SDS should give a good understanding of the type of level of hazard. If you are looking for more information on hazard classification, OSHA and GHS provide detailed information. The flow chart below is an example of the decision logic used to determine the hazard categories. This flow chart is for assessing skin corrosion or irritation. If your facility works with corrosives, this can be helpful information for understanding the hazards.
Occupational Safety and Health Administration, U.S. Department of Labor, Hazard Classification Guidance for Manufacturers, Importers, and Employers, OSHA 3844-02 2016
Updates to the GHS
I contributed a piece to Occupational Health and Safety discussing this topic a few years ago. The Occupational Safety and Health Administration (OSHA) first aligned the hazard communication standards with the GHS in 2012, and a 2024 rule update includes some additional changes. The 2024 rule provides revisions to small container labeling requirements and how mixtures are addressed in Safety Data Sheets.
Critical GHS updates involve hazard classification, flammable gases, labeling, and safety data sheets. OSHA stated that only known or reasonably foreseeable hazards must be included, and that the information should be placed in section 2 of the SDS. Still, it does not specify how this information is disclosed, allowing SDS preparers some discretion. For flammable gases, OSHA adopted subcategories 1A and 1B; changed flammable aerosols to aerosols, which include categories 1-3; and adopted desensitized explosives categories 1-4.
The rules for classifying hazardous substances now include more hazard types, like those that can damage the respiratory system. If a substance is found to be harmful to the respiratory system, it must be labeled accordingly. Experts must decide whether the substance in a mixture will likely cause severe damage to the respiratory system.
OSHA has updated its rules for labeling hazardous substances, changing how chemicals are labeled and what information is included. These changes bring new hazards and precautionary phrases, affecting the labels for many different types of chemicals. They have also created specific phrases for combustible dust, simple asphyxiants, and chemicals that can harm the respiratory tract. Smaller containers may have reduced labeling requirements if including all the necessary information is challenging. However, the entire label must be displayed on the outer packaging.
OSHA has also updated its safety data sheets (SDS) requirements, allowing companies to keep the exact concentration of a hazardous ingredient confidential if it's a trade secret, but requiring them to use specific concentration ranges. A unique identifier must be used if the CAS number is unavailable or if it is a trade secret. Information about physical properties like particle characteristics must also be included. Changes to hazard classes, categories, and phrases will likely affect most SDS and labels. Companies should review the changes and update their SDS and labels before the deadline. OSHA will provide more information and guidance on these changes.
Using GHS for Health and Safety
Over the years, I’ve worked with countless clients and operations, and I’ve learned that people become accustomed to the hazards and precautions they frequently work with. If you work with solvents daily, you get used to the smell and hopefully know how to handle them safely. The real danger lies in assuming that new and unfamiliar chemicals are similar to what you were previously accustomed to.
When it comes to health and safety when working with chemicals, the importance of hazard communication cannot be stressed enough. Hazard communication provides employees with information and training on chemical hazards and how to protect themselves. Understanding how hazard information is provided on labels and SDS, the importance of terms like danger, and the value of pictograms is a simple, effective way to improve that hazard communication process.