Signal Word Chart

The signal word provides the applicator with important information about the toxicity, irritation and sensitization hazards associated with use of that pesticide. Word category is determined by the results of six acute toxicity studies submitted by the pesticide registrant (ingestion, inhalation, dermal absorption, eye effect and skin irritation tests). Danger/Poison products are the most toxic, followed by products marked Danger, then products marked Warning, and Caution products are the least toxic (Source 40 CFR 156).

In general, pesticides with signal words “Danger/Poison” and “Danger” require a 48-72 hr REI, ” Warning” pesticides usually require a 24 hr REI, and “Caution” pesticides usually require a 12 hr REI. Note: Product-specific reentry requirements are set by the chemical’s registrant. Read all labels carefully to determine the right reentry period for the product you are using.