Which signal word on a pesticide label indicates it is highly toxic to humans?

The choice indicating "Danger-Poison" on a pesticide label signifies that the product is highly toxic to humans. This designation is critical for safety, as it alerts users that even a small exposure could lead to serious health effects or potentially fatal outcomes. Signal words on pesticide labels serve as a quick reference for the toxicity level of a product, guiding the user on the necessary precautions to take during handling and application.

In contrast, other signal words such as "Caution" and "Warning" denote lower levels of toxicity. "Caution" indicates that the product is slightly toxic, while "Warning" suggests a moderate level of toxicity. The term "Beware," while it may seem cautionary, is not an official signal word on pesticide labels, and thus does not provide an accurate reflection of the product's toxicity. This hierarchical system allows users to make informed decisions regarding safety measures when dealing with pesticides.