What does the REI indicate regarding entry into treated areas?

The REI, or Re-Entry Interval, specifically indicates the duration of time that must pass after the application of a pesticide before unprotected individuals can enter the treated area safely. This period allows for the dissipation of potentially harmful residues and ensures that individuals are not exposed to any harmful effects of the pesticide before it has had time to settle or degrade. By specifying a limited time after application, the REI helps protect both agricultural workers and the general public from unnecessary exposure to chemicals.

The other options, while related to pesticide use, do not accurately describe the purpose of the REI. For instance, the idea of entry being allowed after one hour does not universally apply, as the specific REI will vary depending on the pesticide and its application. Similarly, while mixing involves caution, it is not directly relevant to the definition of the REI. Weather conditions can affect pesticide effectiveness but are not a determining factor for re-entry intervals, which are based solely on safety guidelines established for the specific chemical used.