What signal word must highly toxic products carry?

Highly toxic products are required to carry the signal word "DANGER" as part of their labeling. This designation indicates that the product poses a significantly higher risk, and even minimal exposure could lead to serious health effects or fatal outcomes. The use of "DANGER" is part of the system designed to communicate hazards clearly and effectively, ensuring that individuals handling the product are aware of the extreme level of toxicity associated with it.

In contrast, other signal words like "WARNING" and "CAUTION" are used for products with lesser degrees of toxicity. "WARNING" indicates that a product is moderately hazardous, while "CAUTION" is used for products that can cause irritation or minor harm but are not considered highly toxic. The category of "POISON" may sometimes appear on labels, typically in conjunction with the "DANGER" signal word, but it is not a standalone indication of toxicity level in the same way. Thus, "DANGER" is the definitive term that highlights the critical nature of the toxicity of these products.