## Facts

- Green Plains Otter Tail, LLC operated an ethanol production facility in Minnesota.
- Pro-Environmental, Inc. designed, manufactured, and installed a regenerative thermal oxidizer (RTO) to burn off pollutants at the facility.
- The RTO’s dampers depended on a hydraulic system that included a pump and a nitrogen-charged accumulator; the accumulator required periodic nitrogen checks and recharging to maintain pressure.
- PEI provided a maintenance manual stating it was “suggested” that the accumulator be checked one week after installation and then monthly; the described procedure required shutting down the unit, draining hydraulic fluid, and using specialized charging/gauging equipment.
- Green Plains never checked or recharged the accumulator’s nitrogen levels.
- In 2014, the hydraulic pump lost pressure, the dampers failed to operate correctly, and an explosion occurred, damaging the RTO and nearby property.
- Green Plains claimed the design was unreasonably dangerous because alternative damper designs (compressed air or counterweights) were allegedly safer and less prone to catastrophic failure if maintenance was neglected.

## Issues

1. Whether the evidence under Minnesota law created a triable issue that the RTO’s hydraulic-accumulator damper design was defective (strict liability and negligence) and proximately caused the explosion.
2. Whether Green Plains’s failure to perform the manual’s suggested nitrogen maintenance was a superseding cause as a matter of law that defeated proximate causation.
3. Whether Green Plains produced evidence that inadequate warnings or instructions about accumulator maintenance proximately caused the explosion.

## Decision

- The court affirmed summary judgment for PEI on the failure-to-warn claim.
- The court reversed summary judgment for PEI on the design-defect/negligence claims, including proximate cause.
- The court remanded for further proceedings on the design-defect/negligence theory.

## Legal Principles

- On summary judgment, the evidence must be viewed in the light most favorable to the nonmovant, and genuine disputes of material fact preclude judgment as a matter of law.
- Under Minnesota products-liability law, evidence of feasible safer alternative designs can permit a jury to find that a design is unreasonably dangerous.
- Superseding cause turns largely on foreseeability; an intervening act (including negligent maintenance) does not break causation if it was reasonably foreseeable, and close foreseeability questions are typically for the jury.
- For failure-to-warn claims, the plaintiff must present evidence that a different or additional warning would likely have altered user conduct; absent such evidence, proximate cause fails.

## Conclusion

The Eighth Circuit held that disputes over design reasonableness and foreseeability of an operator’s noncompliance with “suggested” maintenance required a jury determination, but it rejected the failure-to-warn claim because Green Plains offered no evidence that stronger or different warnings would have changed its maintenance behavior.


Green Plains Otter Tail, LLC v. Pro-Environmental, Inc., 953 F.3d 541 (8th Cir. 2020)