What is advised against doing at an exterior opening?

In the context of safety and proper procedures at an exterior opening, the advised action is to avoid fogging. Fogging typically refers to the introduction of chemicals or substances that can obscure visibility or create a dangerous atmosphere. Safety protocols often dictate that maintaining clear visibility and a safe environment is critical when working near exterior openings, as they serve as potential points of entry or exit for individuals.

Sealing an opening can be a necessary precaution for safety and to prevent contaminants or intruders from entering a structure, while blocking can imply the need to restrict access for safety reasons. Keeping an opening open may allow for ventilation and ensure that air quality is maintained, but introducing fog could compromise safety by limiting visibility or leading to hazardous conditions. Therefore, fogging is the least advised action in this scenario due to the potential risks it poses.