Are you going to hang him anyhow—and try him afterward?¹

This is a common reaction after first observing the liability associated with the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund).² Most defendants can be strong-armed into settling based on scant circumstantial evidence and seemingly unlimited liability. To avoid this liability, defendants who dispose of petroleum try to benefit from the most significant exemption from CERCLA's definition of hazardous substance—the petroleum exclusion. The scope of the petroleum exclusion is still in a state of flux, but most courts that have considered the exclusion agree that it covers naturally occurring substances and chemicals added during the refining process.³

Several commentators have urged courts to place the burden of proving the exemption⁴ on the defendant, but in so doing, they failed to apply well-founded rules of construction, evidence, and procedure.⁵ The resolution of this issue of statutory construction is critical. Evidence in most Superfund cases is sparse, and neither the plaintiff nor the defendant may have access to the facts necessary to establish whether chemicals in released petroleum occurred naturally, were added during refining, were added later, or were released separately. Accordingly, allocation of the burden of proof may determine whether the exclusion applies to a particular case.

This Dialogue examines which party should bear this burden. It analyzes the text and legislative history of CERCLA, as well as case law on the burden of proving statutory exceptions generally and the petroleum exclusion in particular. It concludes that the plaintiff bears the burden of establishing that the petroleum exclusion does not apply.