What defines a Category B Infectious Substance?

A Category B Infectious Substance is defined as an infectious substance that does not meet the criteria for categorization as a Category A substance. Category A substances are those that pose a significant risk of severe disease or the potential to be a public health threat, thus requiring stringent shipping and handling protocols. In contrast, Category B substances are still considered infectious but do not pose the same immediate risks, allowing for less stringent regulatory controls in their transportation.

This classification is essential for safety in the transportation of materials that, while potentially infectious, do not carry the same level of threat as Category A substances. Understanding this distinction helps ensure that proper safety measures are applied in compliance with regulations, enabling health authorities and transport services to manage risks effectively.

The other choices highlight other factors or categories that do not apply to Category B substances. For instance, stating that it poses an immediate threat or carries a high risk of genetic mutation does not reflect the reality of Category B’s risk classification. Similarly, its presence being limited to laboratory settings does not define it accurately, as these substances can occur in various environments beyond just labs. Thus, the definition aligns perfectly with the distinction that Category B substances are, by definition, not included in Category A, making it the correct answer.