Final answer:
The category not listed under hazardous materials is c) Non-Flammables, as other categories like Pyrophorics, Self-Reactives, and Organic Peroxides indicate hazardous potential, unlike the generally non-reactive Non-Flammables.
Step-by-step explanation:
The category that is not listed under the classification of hazardous materials is c) Non-Flammables. Hazardous materials are classified based on the risks they pose, such as being flammable, reactive, or toxic. Categories such as Pyrophorics, Self-Reactives, and Organic Peroxides represent substances that can ignite or react dangerously under certain conditions. Non-Flammables, on the other hand, do not typically represent a fire or explosion hazard; however, some non-flammable gases are indeed classified as hazardous due to their ability to displace oxygen, but they are not characterized by their flammability like the other options listed.