The U.S. Court of Appeals for the Sixth Circuit recently rejected plaintiffs' efforts to obtain medical monitoring arising out of train derailment that allegedly released dioxin into the environment. In Hirsch et al. v. CSX Transportation, the district court granted summary judgment in favor of CSX Transportation, finding that plaintiffs had not met their burden to show that plaintiffs had been exposed to dioxin in an amount sufficient to cause an increased risk of disease. On appeal, the Sixth Circuit affirmed the district court's ruling, finding that plaintiffs failed to introduce evidence creating a genuine issue as to whether a reasonable physician would order medical monitoring. More specifically, plaintiffs' expert opined that "[o]ne should be afforded the benefit of medical monitoring, if one has sustained a dose equal to or in excess of 50% of [one-in-a-million cancer risk]." In evaluating this expert opinion, the Sixth Circuit found that "Plaintiffs have alleged only a risk that borders on legal insignificance, have failed to produce evidence establishing even this hypothetical risk with any degree of certainty, and have demanded a jury trial based upon their expert's review of this evidence and conclusory statement of the relevant legal standard. In this context, [plaintiff's expert] affidavit amounts to a mere scintilla of evidence." The Sixth Circuit noted that plaintiffs might have survived summary judgment had they obtained medical evidence that they did in fact face a one-in-a-million risk of cancer but that plaintiffs had not done so in this particular case.