Which category has no signal word because it is the least toxic?

• A. Category I
• B. Category II
• C. Category III
• D. Category IV

Answer: (D)

Pesticide labels use signal words to show how dangerous a product is from acute exposure. Four categories reflect increasing hazard, with the strongest warning for the most toxic and progressively less for the others. The least toxic category is the one that doesn’t use any signal word at all, signaling that its acute hazard is low enough that a warning isn’t needed on the label. This means that category carries the minimal risk among the four, so no verbal hazard cue is required. Remember, even the least toxic products require following label directions and safe handling practices to avoid unnecessary exposure.