Final answer:
The 'signal word' on a label indicates toxicity level, providing immediate hazard severity awareness. It's crucial for safety to also refer to safety data sheets for comprehensive hazard information and to understand the hazard diamond on chemical labels.
Step-by-step explanation:
The section of a label that indicates toxicity is the signal word. The signal word is part of the cautionary statement that quickly communicates the level of hazard associated with a chemical. These words such as 'Danger' or 'Warning' provide an immediate indication of the relative severity of the hazard. For a deeper understanding of the toxicity, one should also read the safety data sheets (SDS) which provide comprehensive information about handling chemicals safely and understanding their hazards.
Aside from the signal word, the hazard diamond or fire diamond on labels also conveys important data about the health risks (blue section), flammability (red section), reactivity (yellow section), and other special information (white section) of substances. This quick-reference guide helps to identify chemical hazards at a glance.