Can listed hazardous waste escape the requirements of Subtitle C¹ of the Resource Conservation and Recovery Act (RCRA),² without being delisted, simply by being mixed with other material? Under the mixture rule that the U.S. Environmental Protection Agency (EPA) issued in 1980,³ the answer is no. But the U.S. Court of Appeals for the District of Columbia invalidated the mixture rule in Shell Oil Co. v. U.S. Environmental Protection Agency,⁴ and the U.S. Court of Appeals for the Eighth Circuit held that Shell Oil applies retroactively.⁵ Although EPA reissued the mixture rule in 1992,⁶ and the D.C. Circuit upheld the reissued rule,⁷ the question remains: Were listed hazardous waste mixtures created before 1992 subject to Subtitle C?

In their Dialogue, Rebuttal: The Mixture Rule and the Environmental Code,⁸ Van Carson, Philip Schillawski, and Mark Shere argue that Subtitle C does not apply to these mixtures. In response to the Comment EPA's Mixture Rule: Why the Fuss?,⁹ which appeared in the December 1994 issue of ELR — The Environmental Law Reporter, they say that EPA cannot, based on unwritten principles, require that such mixtures be managed as hazardous waste. To subject such mixtures to Subtitle C, they say, would require the management of material that is not dangerous.