Whether a trial court may categorically exclude expert testimony in toxic tort cases without quantitative exposure data and whether the abuse of discretion standard applies when no substantive reliability analysis is conducted

QUESTION PRESENTED The admission of expert testimony in federal courts is governed by Federal Rule of Evidence 702 and this Court's decision in Daubert v. Merrell Dow Pharmaceuticals, Inc. 509 U.S. 579, 592, 113 S. Ct. 2786, 125 L. Ed. 2d 469 (1993) and its progeny. In toxic tort cases, the Fifth Circuit requires plaintiffs to provide "scientific knowledge of the harmful level of exposure to a chemical" as a_ prerequisite to establishing general causation, even when extensive peer-reviewed epidemiological studies demonstrate that exposure to the toxic agent increases disease incidence in exposed populations. The questions presented are: 1. Whether a trial court may categorically exclude expert testimony in toxic tort cases solely because the expert cannot quantify precise exposure levels, even when substantial peerreviewed epidemiological evidence demonstrates increased disease incidence in exposed populations and quantitative exposure data is unavailable or impossible to obtain. 2. Whether the abuse of discretion standard of review remains appropriate when a trial court fails to conduct any substantive analysis of the reliability of expert testimony under Rule 702 and instead applies a categorical rule requiring quantitative exposure data in all toxic tort cases.