"Caution" Signal-Word Rule Change
Mark Mohr, Ag. Eng. Dept., Extension Specialist, 360t Agricultural
Engineering Sciences Building, (MC-644), Urbana, IL, (217) 333-9418,
The US EPA has changed the signal-word requirements for the least
toxic category of pesticides, those that fall into toxicity category
IV. Starting February 12, 2002, if a pesticide falls into the
least toxic category for all routes of exposuresuch as oral,
dermal, and inhalationthe product label will no longer be
required to show the signal word "caution," though the
word may be used by the manufacturer voluntarily. The child-hazard
warning is still required on all products, and other uses of signal
words stay the same.
Signal words are assigned to a product based on the toxicity
of the product. There are four toxicity categories, and a signal
word is assigned to each of the first three categories. Ranked
from most to least toxic, the signal words are "danger"
(or "dangerpoison"), "warning," and
"caution," for categories I, II, and III, respectively.
Under the old signal-word rules, pesticides in category IV were
also required to bear the word "caution." The EPA sought
to clarify the difference between categories III and IV by using
a different signal word for the least toxic category. Because
no suitable word could be found to indicate a lower risk from
toxicity than "caution," the new rules make the use
of the signal word "caution" optional on the labels
of products in toxicity category IV.