A recent decision from the Second Circuit found that a plaintiffs' failure to identify the specific contaminant alleged to present an imminent and substantial harm to human health or the environment was fatal to plaintiffs' RCRA citizen suit. In the case of Brod v. Omya, Inc., the plaintiffs filed a RCRA citizen suit notice that identified 21 contaminants that they alleged were being released into the environment, thereby creating an imminent and substantial endangerment within the meaning of RCRA. After waiting the requisite 90 days, plaintiffs filed a RCRA citizen suit action in the United States District Court for the District of Vermont. During the pendency of the litigation, it was discovered that arsenic and aminoethylthanolamine ("AEEA") were present in groundwater beneath the site. Plaintiffs attempted to rely on the presence of these two additional contaminants in further support of their argument that defendant's releases were creating an imminent and substantial endangerment. The district court dismissed plaintiffs' RCRA citizen suit. On appeal, the Second Circuit noted that none of the 21 contaminants originally identified in plaintiffs' RCRA notice were present at levels sufficient to create an imminent and substantial endangerment to human health or the environment (none of these contaminants exceeded the levels set forth in Appendix 1 of 40 CFR Part 257). With respect to the two additional contaminants (arsenic and AEEA), the Second Circuit found that plaintiffs' failure to identify these two contaminants in the original RCRA notice precluded plaintiffs from relying on those contaminants to argue that an imminent and substantial endangerment existed. The Second Circuit therefore affirmed the district court's dismissal of plaintiffs' RCRA claims.