Describe outer packaging in the context of hazardous goods.

The concept of outer packaging in the context of hazardous goods is defined as a strong box capable of containing both the primary and secondary packaging. This is crucial because outer packaging serves as the first line of defense against potential leaks or spills, ensuring that hazardous materials are securely contained during transportation. It is designed to withstand various conditions that may occur in transit and provides physical protection for the contents inside. Proper outer packaging must comply with regulations that specify the material strength, structure, and compatibility with the hazardous contents, thereby ensuring safety in the event of an accident or exposure to environmental factors.

In contrast, other options listed do not meet the stringent requirements necessary for outer packaging of hazardous goods. Lightweight bags and flexible pouches may not provide adequate protection or containment, while a sealed envelope is typically used for documentation rather than for holding hazardous materials. Thus, the choice of a robust box is essential for compliance with safety standards and regulations regarding the transportation of dangerous goods.