What precaution should be taken when using Penta?

The correct choice emphasizes the importance of minimizing visible mist when spraying Penta, which is a type of wood preservative. This precaution is vital for several reasons. First, minimizing visible mist helps reduce the risk of inhalation exposure to the chemicals present in Penta. Inhalation can lead to health hazards, particularly since these chemicals can be irritants or harmful when absorbed into the respiratory system.

Moreover, minimizing mist helps ensure that the product is applied effectively without significant drift, allowing for better targeted application and reducing environmental contamination. Properly controlling the spray technique can lead to more efficient use of the product, allowing the preservative to penetrate the wood where it is needed most, rather than dispersing into the air or nearby surfaces.

Additionally, the other options present practices that introduce unnecessary risks, such as mixing in open systems (which can lead to uncontrolled reactions or spills), relying on protective clothing (which contradicts safety guidelines), or applying during heavy rain (which could wash away the preservative before it sets). Thus, the emphasis on controlling mist during spraying is crucial for both safety and effective wood preservation.