How long must warning signs remain posted after the expiration of the REI?

The correct duration for warning signs to remain posted after the expiration of the Restricted Entry Interval (REI) is three days. This practice is designed to ensure that individuals entering treated areas are adequately informed of any potential residual pesticide hazards that may still be present, thereby promoting safety measures for agricultural workers and the general public.

The posting period allows for any lingering effects of the pesticide treatment to dissipate while adequately informing anyone entering the area that pesticides were applied recently. Understanding this protocol is crucial for compliance with pesticide regulation enforcement and for protecting the health of workers and the community.

The other options do not meet the necessary safety standards and compliance requirements set by regulatory authorities, as a shorter period such as one day or 12 hours could allow for unsafe exposure. Meanwhile, a longer posting period of seven days may also unnecessarily prolong the awareness window, which is not mandated. Therefore, the three-day requirement strikes an optimal balance between safety and practicality.