Which of the following is NOT a type of packaging mentioned?

In the context of hazardous materials transportation and packaging, packaging types are defined according to specific standards and practices to ensure safety and compliance. Single packaging, combination packaging, and overpacks are recognized categories in hazardous materials shipping, each serving different purposes.

Single packaging refers to the use of a single container that holds the hazardous material and is designed to meet transport regulations. Combination packaging involves using a combination of containers, like an inner receptacle and an outer package, which allows for better containment during transit. Overpacks are used to group multiple containers for easier handling and to protect them from damage.

Rigid packaging, on the other hand, is not classified as a specific type of hazardous materials packaging in official guidelines. While rigid materials (like plastic or metal containers) may be used, the term does not align with the formally recognized types and standards that define how hazardous materials should be packaged for transport. Therefore, identifying rigid packaging as a separate type does not comply with the established categories, making it the correct choice as the option that is not recognized as a type of packaging for hazardous materials.