Code of Federal Regulations Title 40. Protection of Environment § 40.157.22 When required

(1) The pesticide has an acute oral LD₅₀ of 1.5 g/kg or less;

(2) The pesticide has an acute dermal LD₅₀ of 2000 mg/kg or less;

(3) The pesticide has an acute inhalation LC₅₀ of 2 mg/liter or less;

(4) The pesticide is corrosive to the eye (causes irreversible destruction of ocular tissue) or causes corneal involvement or irritation persisting for 21 days or more;

(5) The pesticide is corrosive to the skin (causes tissue destruction into the dermis and/or scarring) or causes severe skin irritation (severe erythema or edema) at 72 hours;  or

(6) The pesticide or device has such characteristics that, based upon human toxicological data, use history, accident data or such other evidence as is available, the Agency determines there is serious hazard of accidental injury or illness which child-resistant packaging could reduce;  and