The U.S. Environmental Protection Agency has established four Toxicity Categories for acute hazards of pesticide or disinfectant products. Category I is the highest toxicity category.
Signal words such as Danger, Poison, Warning, or Caution designate the level of toxicity. Most human hazard, precautionary, and human personal protective equipment statements are based upon the Toxicity Category of the pesticide or disinfectant product as sold or distributed.
In addition, toxicity categories may be used for regulatory purposes other than labeling, such as classification for restricted use and requirements for child-resistant packaging. In certain cases, statements based upon the Toxicity Category of the product as diluted for use are also permitted.
A Toxicity Category is assigned for each of five types or routes of acute exposure:
1. Oral
2. Inhalation
3. Dermal toxicity
4. Skin irritation
5. Eye irritation
Toxicity Category I
Any pesticide or disinfectant product meeting the criteria of Toxicity Category I for any route of exposure must bear on the front panel the signal word ‘‘DANGER.’’ In addition, if the product is assigned to Toxicity Category I on the basis of its oral, inhalation, or dermal toxicity (as distinct from skin and eye irritation), the word ‘‘Poison’’ must appear in red on a background of distinctly contrasting color, and the skull and crossbones symbol must appear in immediate proximity to the word ‘‘Poison.’’
Toxicity Category II
Any pesticide or disinfectant product meeting the criteria of Toxicity Category II as the highest category by any route of exposure must bear on the front panel the signal word ‘‘WARNING.’’
Toxicity Category III
Any pesticide or disinfectant product meeting the criteria of Toxicity Category III as the highest category by any route of exposure must bear on the front panel the signal word ‘‘CAUTION.’’
Toxicity Category IV
A pesticide or disinfectant product meeting the criteria of Toxicity Category IV by all routes of exposure is not required to bear a signal word. If a signal word is used, it must be ‘‘CAUTION.”
