By Kirstee Schutte, Nebraska Extension Master Gardener
Signal words are terms that appear on every pesticide label to denote the relative acute toxicity of the product to humans. Pesticides labeled DANGER – POISON are in hazard class 1 and are considered highly toxic. Pesticides labeled DANGER are also hazard class 1 and highly toxic, but they are based on the corrosive properties of the product. Pesticides labeled WARNING are in hazard class 2 and are considered moderately toxic. Pesticides labeled CAUTION are in hazard class 3 and considered slightly toxic.