## Facts

- Michael M. Mavroudis, Jr. worked for the United States Navy on ship conversion projects at the Puget Sound Naval Shipyard, including nearly four years converting the U.S.S. Wright.
- During the ship-conversion work, Mavroudis used three asbestos-containing insulation products.
- One insulation product, “Kaylo,” was manufactured by Owens-Corning Fiberglas Corporation (OCF), which became the appellant on appeal.
- After retiring, Mavroudis was diagnosed with malignant mesothelioma, a disease associated with asbestos exposure.
- Mavroudis sued multiple manufacturers, including OCF, asserting failure-to-warn theories (negligence and product liability). After he died, his widow, Denise J. Mavroudis, was substituted as plaintiff, individually and as personal representative of his estate.
- At trial, a medical witness testified that all of Mavroudis’s asbestos exposures at the shipyard probably contributed to causing his mesothelioma, but the witness could not identify which exposure (or product) actually caused the disease.
- The witness also testified that even a smaller portion of Mavroudis’s total asbestos exposure (described as 10 percent) could have been enough to cause mesothelioma.
- On causation in fact, the jury was instructed that plaintiff did not need to prove that, but for exposure to Kaylo, Mavroudis would not have developed mesothelioma; instead, plaintiff had to prove Kaylo was a “substantial factor” in causing the illness even if the illness might have occurred anyway.
- On warnings, the jury received an instruction stating the duty to warn arises whenever a reasonable person using the product would want to be warned of the risk of harm.
- The jury returned a verdict for plaintiff and awarded damages exceeding $1 million.
- After trial, the court held a reasonableness hearing regarding plaintiff’s settlements with other defendants and found the settlements reasonable.
- OCF appealed, challenging the causation instruction, the duty-to-warn instruction, the trial court’s refusal to apply the Washington Product Liability Act (WPLA), and the timing and basis of the post-trial reasonableness hearing.

## Issues

1. Whether the trial court erred by instructing on causation in fact using a “substantial factor” test rather than a strict “but-for” test in a multiple-exposure asbestos case.
2. Whether the duty-to-warn instruction misstated Washington law by framing the duty around what a reasonable user would want to know, and if so, whether the error required reversal.
3. Whether the WPLA applied when the mesothelioma was diagnosed after the Act’s effective date, but the asbestos exposure and disease-starting tissue changes occurred before the Act became effective.
4. Whether the trial court abused its discretion by holding a post-trial settlement reasonableness hearing, by using an improper timing reference point for reasonableness, or by finding the settlements reasonable.

## Decision

- The Court of Appeals of Washington, Division One affirmed the judgment for plaintiff.
- The court held the substantial-factor causation instruction was proper in this asbestos case involving multiple exposures where isolating a single necessary exposure was not possible on the proof presented.
- The court held the duty-to-warn instruction used the wrong standard for when the duty arises, but the error was harmless in light of the verdict returned and the overlap between the liability theories submitted.
- The court held the WPLA did not apply because the injury-producing exposure and the tissue changes leading to the disease occurred before the Act’s effective date.
- The court held OCF was not prejudiced by the post-trial timing of the reasonableness hearing, approved the trial court’s focus on the information available when the settlements were made, and declined to reach OCF’s evidentiary-sufficiency argument due to inadequate briefing.

## Legal Principles

- When multiple acts or exposures may each be sufficient to cause an indivisible harm and the evidence cannot identify a single necessary cause, Washington law permits a causation-in-fact instruction requiring proof that the defendant’s conduct or product was a substantial factor in producing the harm, rather than strict “but-for” causation.
- In failure-to-warn claims, the duty to warn is judged by what a reasonably prudent manufacturer exercising ordinary care would provide, not by what a reasonable user would want to know; an instruction using the user-focused formulation misstates the standard.
- An erroneous jury instruction does not require reversal unless the complaining party shows prejudice; an incorrect warning-duty instruction can be harmless when the verdict and record show the outcome was not affected.
- The WPLA does not apply retroactively to asbestos-related disease claims when the injury-producing event (exposure) and the initial tissue changes occurred before the statute’s effective date, even if diagnosis occurs later.
- Trial courts may conduct reasonableness hearings concerning settlements that affect nonsettling defendants; the reasonableness determination should be made based on information available at the time the settlements were made, and the timing of the hearing is reviewed for prejudice and abuse of discretion.

## Conclusion

The appellate court affirmed a mesothelioma verdict against Owens-Corning based on evidence that exposure to its Kaylo insulation was among several contributing asbestos exposures, approving a substantial-factor causation instruction in a multiple-exposure setting, treating an incorrect duty-to-warn instruction as harmless, declining to apply the WPLA because exposure and disease-starting tissue changes predated the Act, and upholding the trial court’s post-trial reasonableness determinations for settlements with other defendants.


Mavroudis v. Pittsburgh-Corning Corporation, 935 P.2d 684 (1997)