"Any substance that can threaten health, safety, and property being transported" (see full definition at The Law Dictionary).
"A number of terms (e.g., "hazardous chemicals," "hazardous materials," "hazardous waste," and similar nomenclature) refer to substances that are subject to regulation under one or more federal environmental laws. State laws and regulations also provide additional, similar, or identical terminology that may be confused with the federally defined terms. Many of these terms appear synonymous, and it is easy to use them interchangeably. However, in a regulatory context, inappropriate use of narrowly defined terms can lead to confusion about the substances referred to, the statutory provisions that apply, and the regulatory requirements for compliance under the applicable federal statutes."
Read more about 'Hazardous Terminology' in the U.S. Department of Energy's CERCLA Information Brief EH-231-003/0191, which provides regulatory definitions and references for the precise terminology that should be used when referring to "hazardous" substances regulated under federal environmental law.
“Hazardous Materials” means any raw material, intermediate, product, byproduct, pollutant, contaminant, chemical, solvent, waste, preparation or any other substance or material (whether solid, semi-solid, liquid or gas) that is (a) defined as a “hazardous substance”, “toxic substance”, “hazardous waste”, “dangerous preparation”, “dangerous substance”, “substance of very high concern” or any other term of similar import under any Environmental Law, (b) infectious, carcinogenic, mutagenic, persistent, ignitable, corrosive, reactive, explosive, poisonous, toxic or otherwise hazardous or dangerous, or (c) listed, defined, designated, classified or otherwise regulated or controlled under, subject to, or that may form the basis for any Liability under any Environmental Law. The term Hazardous Materials includes petroleum and all byproducts and derivatives thereof, asbestos and asbestos-containing materials in any form or condition, radioactive materials and byproducts, urea-formaldehyde, lead and lead-based paint, polychlorinated biphenyls, and any other material or substance that is or that may present a threat to human health or the environment.
"Hazardous Materials" means (i) any substance, emission or material including, but not limited to, asbestos, now or hereafter defined as, listed as or specified in a Applicable Law as a "regulated substance," "hazardous substance," "toxic substance," "pesticide," "hazardous waste," "hazardous material" or any similar or like classification or categorization under any Environmental Law including by reason of ignitability, corrosivity, reactivity, carcinogenicity or reproductive or other toxicity of any kind, (ii) any products or substances containing petroleum, asbestos, or polychlorinated biphenyls or (iii) any substance, emission or material determined to be hazardous or harmful.