Which of the following is NOT a characteristic that makes a material hazardous?

Biodegradable materials are not inherently hazardous based on their ability to break down and decompose in the environment. In contrast, flammable, reactive, and corrosive materials possess specific properties that can pose immediate risks to safety, health, and the environment. Flammable materials can ignite easily and cause fires, reactive substances can undergo dangerous reactions when mixed with other materials, and corrosive substances can cause destruction of living tissue or severe corrosion of materials upon contact.

Since being biodegradable does not directly refer to a harmful physical or chemical characteristic, it is indeed the option that does not align with the definition of a hazardous material. In safety protocols and regulations, the focus tends to be on those properties that present a risk to individuals or the environment, which is why the other three characteristics are associated with hazardous materials.