What signal word is used to describe less toxic compounds in Categories III and IV?

The signal word used to describe less toxic compounds in Categories III and IV is "Caution." This term is specifically designated for substances that pose a lower risk to human health and the environment compared to those categorized under more hazardous labels.

Categories III and IV include pesticides and chemicals that have been assessed to have a lower toxicity, thus making "Caution" the appropriate signal word to indicate their relative safety during use. It effectively communicates to users that while these compounds require careful handling, the risk is less severe compared to those labeled with "Danger" or "Warning," which indicate higher toxicity and greater precautions that need to be taken.

To summarize, "Caution" serves as an important safety label in the context of chemical handling, ensuring users understand the relative risk associated with these less toxic compounds.