Which signal word is reserved for the most severe hazard categories in the Global Harmonized System (GHS)?

The signal word reserved for the most severe hazard categories in the Global Harmonized System (GHS) is "Danger." This terminology is specifically used to indicate a high level of hazard associated with a chemical or substance, alerting users to the potential for serious harm. The use of "Danger" is a clear and immediate indication that the risks are significant and that proper precautions must be taken to ensure safety.

In contrast, the other terms such as "Warning," "Caution," and "Note" indicate lower levels of hazard severity. "Warning" is used for moderately hazardous substances, while "Caution" typically refers to lower hazard situations that still require attention. "Note" does not function as a signal word within the GHS framework and is used for supplementary information, emphasizing that it does not convey a severity-related hazard level. Understanding the hierarchy of these terms is crucial for effective communication about chemical safety and risk management.