## Facts

- Property owners in Dayton, Ohio’s McCook Field neighborhood alleged that nearby automotive and dry-cleaning operations released volatile organic compounds and other hazardous substances into groundwater beneath their properties.
- Plaintiffs alleged the contamination created a risk of vapor intrusion, exposing residents to carcinogens inside homes and buildings, despite use of municipal drinking water.
- The area was designated a federal Superfund site; plaintiffs alleged defendants were indifferent to harms resulting from releases.
- Plaintiffs filed a putative class action on behalf of roughly 540 properties, asserting Ohio-law claims including private nuisance, negligence, negligence per se, strict liability, and unjust enrichment.
- The case was removed to federal court under the Class Action Fairness Act and consolidated with related litigation.

## Issues

1. Whether a court may certify particular issues for class treatment under Federal Rule of Civil Procedure 23(c)(4) when the action as a whole does not satisfy Rule 23(b)(3) predominance.
2. Whether the certified issues satisfy Rule 23(b)(3)’s predominance and superiority requirements when evaluated at the issue level.

## Decision

- The Sixth Circuit affirmed the district court’s certification of seven issues under Rule 23(c)(4).
- The court held that Rule 23(c)(4) authorizes certification of discrete issues even if a full Rule 23(b)(3) class cannot be certified for the entire action.
- The court agreed that, although individualized proof of injury, causation, and damages defeated predominance for a full liability-only class under Ohio law, the certified issues could be resolved with common proof.
- The court held the district court did not abuse its discretion in finding that issue-class treatment was superior because resolving common issues once would materially advance the litigation and reduce duplication across many property claims.

## Legal Principles

- Rule 23(c)(4) permits class certification “as to particular issues,” and predominance need not be satisfied at the level of the entire cause of action as a prerequisite to issue certification.
- For an issue class, Rule 23(b)(3) predominance is assessed with respect to the specific issues certified; remaining individualized matters do not necessarily defeat issue-level predominance.
- Rule 23(b)(3) superiority does not require class treatment to resolve all aspects of liability; it is enough that issue certification substantially improves efficiency and consistency compared to repeated individual litigation.
- In mass-tort and environmental contamination cases, courts may separate common questions (e.g., defendants’ conduct and the existence/nature of contamination) from individualized questions (e.g., injury, property-specific exposure, and damages) for staged adjudication.

## Conclusion

The Sixth Circuit held that a district court may certify discrete common issues under Rule 23(c)(4) even when individualized injury and causation questions prevent certification of a full Rule 23(b)(3) class, and it upheld issue certification where common proof predominated and class treatment would materially advance the case.


Martin v. Behr Dayton Thermal Prods. LLC, 896 F.3d 405 (6th Cir. 2018)