What regulatory document outlines hazard classifications information?

The correct response pertains to 49 CFR, Section 173, which specifically addresses the classifications and definitions of hazardous materials. This section is integral to understanding how various materials are categorized based on their potential risks and properties.

Within 49 CFR, Section 173, there are detailed criteria that determine the classification of hazardous materials for transport, including aspects such as flammability, toxicity, or reactivity. This is essential for ensuring that appropriate safety measures and regulations are in place to protect public safety and the environment during the transport of hazardous materials.

On the other hand, the other sections referenced pertain to different aspects of hazardous materials regulations. Section 172 deals primarily with labeling, marking, and placarding requirements for hazardous materials. Section 174 focuses on regulations concerning the transportation of hazardous materials by rail. Finally, Section 175 addresses the transport of hazardous materials by air. Each of these sections plays a role in the overall framework of hazardous materials regulations, but Section 173 specifically deals with hazard classification, making it the pertinent choice for this question.