Final answer:
The United States Department of Transportation (USDOT) has identified nine classes of hazardous materials based on the dangers they pose during transportation.
Step-by-step explanation:
Classes of Hazardous Materials
The United States Department of Transportation (USDOT) has identified nine classes of hazardous materials based on the dangers they pose during transportation. These classes include explosives, gases, flammable liquids, flammable solids, oxidizers, toxic substances, infectious substances, radioactive materials, and corrosive materials.
Each class has specific criteria and regulations for handling, packaging, and transporting the materials to ensure safety.