## Facts

- Union Carbide Corporation and Umetco Minerals Corporation owned and operated uranium and vanadium mining/milling facilities and the company town of Uravan, Colorado.
- The companies built and maintained residences and community facilities in Uravan for workers and families.
- Milling operations ended in 1984; the Environmental Protection Agency later placed Uravan on the National Priorities List, residents were evacuated, and remediation began.
- Former residents (and representatives of deceased residents) alleged exposure to radiation from operations at Uravan.
- Plaintiffs asserted (1) personal-injury claims for cancers and thyroid disease allegedly caused by radiation exposure and (2) medical-monitoring claims for asymptomatic plaintiffs allegedly suffering subclinical cellular damage.
- The action was brought as a public liability action under the Price–Anderson Act, with Colorado substantive tort law supplying the negligence and causation standards.
- The district court granted summary judgment against the personal-injury claims for lack of evidence of factual causation and dismissed medical-monitoring claims for failure to show “bodily injury” under the Price–Anderson Act.
- Plaintiffs appealed.

## Issues

1. Under Colorado tort law, must toxic-exposure plaintiffs prove but-for causation (including as refined for multiple-cause situations), or is showing the defendant’s conduct was a substantial factor sufficient by itself?
2. Under the Price–Anderson Act, do asymptomatic subclinical changes (e.g., DNA damage and cell death) qualify as “bodily injury” sufficient to support medical-monitoring relief?

## Decision

- The Tenth Circuit affirmed the judgment for defendants.
- The court held that Colorado law requires but-for causation; the substantial-factor concept refines but-for analysis in multiple-cause cases but does not replace it.
- The court held plaintiffs’ evidence did not permit a finding that defendants’ radiation was a but-for cause (or a necessary component of a causal set sufficient to cause) the alleged diseases.
- The court held that asymptomatic, subclinical cellular changes are not “bodily injury” under the Price–Anderson Act; therefore, medical-monitoring claims failed as a matter of law.

## Legal Principles

- In Colorado tort cases, a plaintiff must prove factual causation (but-for causation) and that the defendant’s conduct was sufficiently connected to the harm; “substantial factor” is not an alternative that eliminates but-for causation.
- In multiple-cause contexts, conduct may satisfy but-for causation if it is a necessary component of a set of conditions sufficient to produce the harm; evidence of increased risk alone is insufficient.
- Price–Anderson public liability actions incorporate state substantive tort standards unless inconsistent with the federal statute.
- For Price–Anderson purposes, “bodily injury” requires more than microscopic or molecular-level changes without manifest, objective injury; absent bodily injury, medical-monitoring claims are not cognizable under the Act.

## Conclusion

The court affirmed dismissal of all claims because the personal-injury plaintiffs lacked evidence that defendants’ radiation was a but-for cause of their diseases under Colorado law, and the asymptomatic plaintiffs’ asserted subclinical cellular effects did not satisfy the Price–Anderson Act’s “bodily injury” requirement for medical monitoring.


June v. Union Carbide Corp., 577 F.3d 1234 (10th Cir. 2009)