Most of us do not have an in-depth understanding of terms like hazard, toxicity, exposure, and risk management, as they relate to the pesticide label. Here is an overview.
Directions, precautions, and restrictions on pesticide labels are based on extensive research studies with built-in safety factors. As with many other products (medications, electrical appliances, gasoline, etc.), following the label is the best way you can prevent harm to yourself, to others, and to the environment.
Pesticide labels warn of potential hazards of the product, explain how to reduce potential exposure to humans and the environment, and provide first aid instructions in case of accidents. Examples from the label include Hazards to Humans and Domestic Animals, Personal Protective Equipment, and First Aid statements, and the Signal Word (Caution, Warning, or Danger). All of this information is based on the results of acute toxicity studies performed during product development. The signal word is based on the route of exposure with the highest level of toxicity; for example, if a product is slightly toxic by most routes of exposure but highly toxic by inhalation, the label will have a signal word indicating high toxicity.
The toxicity of a pesticide is its potential to cause damage to any living organism or its components, when exposure occurs. Both amount (dose) and time (length and/or frequency) of exposure are important in understanding the toxicity of a pesticide.
There are two types of toxicity effects – acute and chronic. Both can be predicted under experimental conditions.
Acute toxicity effects are those toxic effects that appear immediately or within 24 hours of exposure. These types of effects are measured under experimental conditions for 24 hours or less, using one or more high doses (exposures). A pesticide with a high acute toxicity can be deadly or destructive even when a very small amount is absorbed through the skin (acute dermal toxicity), inhaled (acute inhalation toxicity), ingested (acute oral toxicity), or spilled in the eyes (acute eye irritation).
Sub-chronic and chronic toxicity effects are toxic effects from longer-term exposures. These types of effects are measured under experimental conditions for 21 days to 2 years or even longer, using continuous or repeated exposures. For many pesticides, the toxic effects following chronic exposure are quite different from those produced by acute exposure.
The EPA determines the level of risk by considering toxicity and exposure (as well as other factors). Based on the level of risk, specific directions, precautions, and restrictions are included on the label – this is risk management. Following the label keeps your exposure below potentially harmful levels.
Not following the label is not only illegal – it is also dangerous because it ignores practices put in place to prevent hazard, exposure, and risk.
*Detailed research studies are also conducted to determine acute and chronic toxicity to birds, fish, invertebrates, honeybees and mammals, and impacts on water, soil and air. The resulting use of these studies is the same – directions, precautions, restrictions, etc. on the label, to guide pesticide users.