What class does a material that causes significant annoyance or discomfort to flight crew members belong to?

A material that causes significant annoyance or discomfort to flight crew members is classified as Class 9. This classification encompasses materials that pose a risk that may not fall under the other more hazardous classes but can still be problematic in specific situations. Class 9 includes a range of miscellaneous dangerous goods, which often involve issues related to human factors, such as irritation or discomfort. This classification acknowledges that while the materials may not be immediately harmful in a traditional sense, they can still create unsafe conditions by distracting or adversely affecting the performance of crew members.

Understanding this classification is important for ensuring safety in transportation and handling procedures, as it highlights the need for vigilance regarding not just overtly dangerous materials but also those that could cause disruption or discomfort during operations.