Mixture Rule in the United States

Mixture Rule in Environmental Law

A principle created by the Environmental Protection Agency (EPA) to prevent people from diluting hazardous waste in order to avoid regulation. The EPA’s standard motto in this area is “the answer to pollution is not dilution.” According to this rule, if a hazardous waste is mentioned by name in the EPA regulations, adding any other substance to it results in a mixture that is also a hazardous waste.

The mixture rule, as well as the derived from rule, was invalidated in the case of Shell Oil Company v. Environmental Protection Agency. Later the Environmental Appeals Board determined that the effect of the Shell Oil decision was to erase the two rules from the time they were created in 1980 until reinstatement by emergency rule on 3 March 1992. The case before the Environmental Appeals Board was In the Matter of Hardin County (1994).
Based on “Environment and the Law. A Dictionary”.