Which signal word indicates high toxicity and requires caution?

The signal word that indicates high toxicity and requires caution is "Danger." This term is used on pesticide labels to convey that the product poses a significant risk if mishandled or used improperly. The presence of this word suggests that the substance can cause severe harm, including the potential for death or serious injury, and emphasizes the need for users to follow safety guidelines meticulously when handling the product.

In contrast, "Warning" denotes a moderate level of toxicity, and "Caution" indicates a lower toxicity level, where risks are minimal compared to those associated with "Danger." "Danger-Poison" also signals high toxicity, but specifically implies an acute risk of poisoning. While both "Danger" and "Danger-Poison" indicate severe toxicity, the question focuses on identifying just one signal word for high toxicity, which is "Danger." Thus, this answer aligns with the criteria of indicating high toxicity to ensure appropriate safety measures are followed.