Final answer:
The category 'organic' is not typically classified as a type of hazardous substance. Hazardous materials are characterized as chemical, radioactive, and biological, each posing different risks to health and the environment. Option C is correct.
Step-by-step explanation:
The category that is NOT considered a type of hazardous substance is organic. The typical categories of hazardous substances are chemical, radioactive, and biological. Hazardous substances often refer to materials that pose a risk to human health or the environment and include a range of compounds such as toxic chemicals, heavy metals, and persistent organic pollutants.
For clarification, organic substances can indeed be hazardous, but the term 'organic' as a category on its own is typically not used to classify hazardous substances. Rather, hazardous materials are identified by their specific harmful characteristics, such as toxicity or radioactivity, or by being a biological agent capable of causing disease or infections.