40 C.F.R. § 156.62
This section establishes four Toxicity Categories for acute hazards of pesticide products, Category I being the highest toxicity category. Most human hazard, precautionary statements, and human personal protective equipment statements are based upon the Toxicity Category of the pesticide 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 of acute exposure, as specified in the table in this paragraph.
Acute Toxicity Categories for Pesticide Products
| Hazard Indicators | I | II | III | IV |
| Oral LD50 | Up to and including 50 mg/kg | [GREATER THAN]50 thru 500 mg/kg | [GREATER THAN]500 thru 5,000 mg/kg | [GREATER THAN]5,000 mg/kg |
| Dermal LD50 | Up to and including 200 mg/kg | [GREATER THAN]200 thru 2000 mg/kg | [GREATER THAN]2000 thru 20,000 mg/kg | [GREATER THAN]20,000 mg/kg |
| Inhalation LC50 | Up to and including 0.2 mg/liter | [GREATER THAN]0.2 thru 2 mg/liter | [GREATER THAN]2 thru 20 mg/liter | [GREATER THAN]20 mg/liter |
| Eye irritation | Corrosive; corneal opacity not reversible within 7 days | Corneal opacity reversible within 7 days; irritation persisting for 7 days | No corneal opacity; irritation reversible within 7 days | No irritation |
| Skin irritation | Corrosive | Severe irritation at 72 hours | Moderate irritation at 72 hours | Mild or slight irritation at 72 hours |
40 C.F.R. §156.62