What is critical to ensure when filling out Form 8105-B?

When filling out Form 8105-B, it is crucial to ensure that the form is completed after the customer leaves for safety reasons. This form is used for packages that require special handling, and it is essential to complete it in a way that minimizes risks associated with hazardous materials. By filling it out after the customer has left, postal employees can avoid potentially dangerous situations that could arise during the packaging or shipping of hazardous materials while a customer is still present.

The other options do not address the critical safety consideration as effectively. Completing the form at the end of the day may not ensure the same level of safety; doing it with the customer present could lead to unnecessary risks; using the form only for packages over 10 lbs is incorrect as the form pertains to different types of packages regardless of weight. The focus on safety and minimizing risk when handling specific types of packages is a primary reason for the correct practice of completing the form after the customer's departure.