When Congress enacted the Superfund Amendments and Reauthorization Act (SARA) in 1986, it included a provision to address what was perceived as a significant shortcoming in state law. Many states' statutes of limitation at the time began to run when a plaintiff was first injured, whether or not the plaintiff was aware of the injury or its cause. In the case of a long-latency disease, allegedly caused by past exposure to hazardous substances, the limitation period could expire long before the plaintiff was aware that he or she even had a claim.

Congress sought to address this shortcoming by using SARA to add a federal "discovery rule" to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980.4 The new provision added to CERCLA, in §309, ensured that state statutes of limitation would not begin to run until "the date the plaintiff knew (or reasonably should have known) that the personal injury or property damages... were caused or contributed to by the hazardous substance or pollutant or contaminant concerned." This federally required commencement date ensured that a plaintiff allegedly injured by exposure to hazardous substances would not be procedurally barred from bringing a claim before the plaintiff was aware of his or her injury and its cause.