According to 15 USCS § 1261 (f), [Title 15. Commerce and Trade; Chapter 30. Hazardous Substances] the term hazardous substance means:
“1. (A) Any substance or mixture of substances which (i) is toxic, (ii) is corrosive, (iii) is an irritant, (iv) is a strong sensitizer, (v) is flammable or combustible, or (vi) generates pressure through decomposition, heat, or other means, if such substance or mixture of substances may cause substantial personal injury or substantial illness during or as a proximate result of any customary or reasonably foreseeable handling or use, including reasonably foreseeable ingestion by children.
(B) Any substances which the Commission by regulation finds, pursuant to the provisions of section 3(a) [15 USCS § 1262(a)], meet the requirements of subparagraph 1(A) of this paragraph.
(C) Any radioactive substance, if, with respect to such substance as used in a particular class of article or as packaged, the Commission determines by regulation that the substance is sufficiently hazardous to require labeling in accordance with this Act in order to protect the public health.
(D) Any toy or other article intended for use by children which the Commission by regulation determines, in accordance with section 3(e) of this Act [15 USCS § 1262(e)], presents an electrical, mechanical, or thermal hazard.
(E) Any solder which has a lead content in excess of 0.2 percent.
2. The term "hazardous substance" shall not apply to pesticides subject to the Federal Insecticide, Fungicide, and Rodenticide Act [7 USCS §§ 136 et seq.], nor to foods, drugs and cosmetics subject to the Federal Food, Drug, and Cosmetic Act [21 USCS §§ 301 et seq.], nor to substances intended for use as fuels when stored in containers and used in the heating, cooking, or refrigeration system of a house, nor to tobacco and tobacco products, but such term shall apply to any article which is not itself a pesticide within the meaning of the Federal Insecticide, Fungicide, and Rodenticide Act [7 USCS §§ 136 et seq.] but which is a hazardous substance within the meaning of subparagraph 1 of this paragraph by reason of bearing or containing such a pesticide.
3. The term "hazardous substance" shall not include any source material, special nuclear material, or byproduct material as defined in the Atomic Energy Act of 1954, as amended [42 USCS §§ 2011 et seq.], and regulations issued pursuant thereto by the Atomic Energy Commission.”
Pursuant to 50 CFR 37.2 [Title 50 -- Wildlife and Fisheries, Chapter I -- United States Fish and Wildlife Service, Department of The Interior], the term hazardous substances means “petroleum, petroleum products, toxic materials, chemical effluent, explosives, or other materials which are likely to cause significant adverse effects to the refuge's wildlife, its habitat, the environment, or humans.”