For trial lawyers and judges, the U.S. Supreme Court's "Daubert Four"—four unanimous decisions since 1993, Daubert v. Merrell Dow Pharmaceuticals, Inc.,¹ General Electric Co. v. Joiner,² Kumho Tire Co. v. Carmichael,³ and Weisgram v. Marley Co.⁴—overturned 70 years of trial practice regarding expert evidence, rewriting both when scientific and other expert evidence can and cannot be admitted at trial, and how a trial judge's decision to exclude or admit⁵ expert evidence is reviewable on appeal. Before Daubert, when a judge said "call your next witness," the experts in many cases would have been allowed to testify. After Daubert, when the judge instructed a lawyer to "call your next witness," none of the experts involved in these four Supreme Court cases were ultimately allowed to testify, and the same has been true in many other cases since 1993.⁶

This Article applies the Daubert Four to environmental and toxic tort⁷ litigation and regulation in three ways. In part I, the Article sets forth a public policy need, and opportunity, for a "next generation" of environmental regulation and litigation. Part II provides a litigator's guide to Daubert hearings and appeals regarding the admission and exclusion of expert witnesses, and sets forth a "does it work and why?" method for determining whether expert evidence is "reliable" enough to be admitted. Part III combines the new Daubert requirements for the use of experts at trial with a generalization of the underlying Daubert legal analysis of applying nonenvironmental federal law, such as the Federal Rules of Evidence, to environmental litigation. These two dimensions of Daubert are referred to as the "Daubert Litigation Approach." The Daubert Litigation Approach is then applied in 10 illustrative ways.