What action should be taken to maintain safety when handling pesticides?

The recommended action to maintain safety when handling pesticides involves ensuring that the filling hoses never contact tank liquids. This practice is crucial because it prevents contamination and helps to avoid unintentional chemical hazards. By ensuring that the filling hoses do not come into contact with the pesticide solution in the tank, the risk of back-siphoning is eliminated. Back-siphoning could lead to pesticides entering the water supply or contaminating the area, which poses significant health risks to both humans and the environment.

The other options do not promote safe handling practices; using larger quantities than required can lead to excess chemical application, which is wasteful and potentially harmful. Filling tanks to capacity may increase the risk of spills or leaks, endangering both the handler and the environment. Ignoring environmental conditions can lead to improper application and increased risks of pesticide drift, which can compromise both safety and effectiveness.