The Supreme Court declined to review this appeal. It was a fundamental challenge to the general principle that courts substantially defer to the interpretations of administrative agencies in enforcement proceedings. The Fourth Circuit ruled that it must defer to the EPA's interpretation of its benzene standard so long as the interpretation was not "nonsensical." It also ruled that the company must begin to comply with the new interpretation within 90 days after it learned of the interpretation, even though the rule allowed two years for companies to come into compliance.The interpretation at issue involved the minimum threshold for application of the national emission standard for benzene. The standard exempts plants that "use" less than 1,000 megagrams of benzene, and the conflict arises from EPA's interpretation of the word "use." Its interpretation counts as a use each time the material passes a certain point in the process, even if it is recycled. This is like saying that an automobile engine, recycling engine oil, "uses" thousands of gallons of oil a year, since the oil is recycled through the engine so frequently.
Different regional offices within EPA disagreed over this interpretation. Nor is such an interpretation obvious from the language of the standard. Thus, Hoechst Celanese and the NAM and other organizations as amici argued that courts should not automatically defer to the EPA's pronouncements.