020-4 Wyo. Code R. § 4-3
(a) "Hazardous Substance" means any substance or waste which, after release, constitutes a threat to public health or welfare, or other aquatic life or wildlife because of its quantity, concentration, chemical, corrosive, flammable, reactive, toxic, infectious, or radioactive characteristics. The term shall also include all substances so designated by the U. S. Environmental Protection Agency. The term shall not include oil.
(b) "Oil" means insoluble or partially soluble oil of any kind including, but not limited to, crude or fuel oil, lubricating oil, oily sludge, asphalt, crude condensate, gasoline, aviation fuel, kerosene, diesel motor fuels, road oil, waste oil, oil mixed with federally defined nonhazardous wastes and derivatives of mineral, animal, or vegetable oils.
(c) "Predesignated State On-Scene-Coordinator (OSC)" means the state official(s) predesignated by the governor to coordinate and direct state responses to oil or hazardous substance(s) releases and to function as the state representative to the U.S. Environmental Protection Agency, Region VII, Regional Response Team. The Wyoming Oil and Hazardous Substances Pollution Contingency Plan shall contain the designation of the OSC and define his duties.
(d) "Release" includes, but is not limited to, any sudden spilling, leaking, pumping, pouring, emptying, emitting, discharging, dumping, addition of, escaping, leaching, or unauthorized disposal of any oil or hazardous substance which enters, or threatens to enter, waters of the state.
020-4 Wyo. Code R. § 4-3