Causation Instructions Cause Trouble

Causation Instructions Cause Trouble


Significant costs are invested to obtain a defense verdict.  Experienced trial lawyers realize it is equally important to avoid inviting error which will result in a costly retrial.  In the heat of trial, lawyers often press so hard for favorable jury instructions they forget the end goal is to prevail both at trial and on appeal.  Roemmich v. 3M, et. al.[i] teaches that painful lesson in the context of an asbestos/product liability trial.[ii]


The Facts

Beginning in 1970, 3M manufactured a single use mask (the “8710 mask”) to protect against pneumoconiosis and fibrous-producing dusts such as asbestos fibers.  It marketed the 8710 mask to asbestos workers in the insulation trade, with the catchy phrase, “[y]ou don’t have to work yourself to death.”[iii]  3M claimed the 8710 mask protected against asbestosis.  Relying on evidence the U.S. Bureau of Mines had approved the mask, plaintiff’s employer recommended the 8710 mask to its workers.

Unfortunately, the masks tended to leak.  Nonetheless, 3M continued to promote and sell the 8710 mask as protective against asbestos for six years after the National Institute for Occupational Safety and Health warned 3M that single-use masks should not be used for asbestos protection because of leakage from the face seal.  Plaintiff developed mesothelioma after years of using the 8710 mask and exposure to asbestos from multiple sources.


The Trial

3M asked for both the substantial factor causation instruction, typically used in multiple source toxic material cases,[iv] and the standard proximate cause instruction requiring plaintiff to meet the higher burden of “but-for” causation.[v]  The instruction combined both standards into a single instruction.

3M also convinced the trial court to instruct the jury on superseding/intervening cause, arguing the employer’s negligence superseded that of 3M.  The instruction also deviated from the standard WPI 15.05 version by omitting the last paragraph, which reads:

It is not necessary that the sequence of events or the particular resultant [injury][event] be foreseeable. It is only necessary that the resultant [injury][event] fall within the general field of danger which the defendant should reasonably have anticipated.[vi]

The jury found 3M negligent, but they also found the negligence was not a proximate cause of plaintiff’s injury.



On appeal, plaintiff challenged the causation instructions and the exclusion of their expert testimony.  Division One found instructional errors related to both the proximate cause and superseding cause instructions.  3M lost its defense verdict, and the case was remanded for a new trial.

Plaintiff successfully argued the “but for” causation instruction was error.  3M argued the case did not involve multiple defendants whose products were independently capable of causing harm.  It pointed out that its product was a non-harmful respirator that did not contain asbestos.  Siding with plaintiff, Division One noted the evidence at trial established 3M’s mask at least partly contributed to plaintiff’s exposure and harm.  It concluded: “Applying the ‘but-for’ causation test would absolve 3M of responsibility despite this evidence.”[vii]

Turning to the superseding cause instruction, plaintiff argued the trial court erred in giving a superseding cause instruction and the instruction did not properly set forth the burden of proof.  Division One discussed the high standards required before a cause can be a superseding/intervening cause.  Citing to Campbell v. ITE Imperial Corp.[viii] and Albertson v. State,[ix] the court ruled, as a matter of law, that the employer’s negligence was reasonably foreseeable.  It was not the type of extraordinary act that could supersede 3M’s negligence.  Because the instruction was not appropriate, the appellate court did not reach the burden of proof issue.

The court concluded that both instructions misinformed the jury and prejudiced the plaintiff.[x]



Multiple source toxic tort cases should always go to the jury only on substantial factor causation instructions.  Attorneys should not combine instructions in these cases.  If two causation instructions are applicable, attorneys should set them out separately and alert the jury as to what facts apply to which instruction.  Superseding cause instructions are rarely worth the risk of losing a defense verdict. Jury instruction error is one of the most common grounds for reversal. If the case’s facts genuinely support giving this instruction, attorneys should be sure to give the entire instruction.

About the Authors:  Bertha B. Fitzer, J.D., LL.M., and Jennifer M. Veal, Esq. are partners in Tyson & Mendes’ Seattle office.  They have successfully argued complex causation issues both before the Court of Appeals and the Washington Supreme Court.  With 15 defense verdicts to their credit in the last 7 years, they have never lost a defense verdict on appeal.




[i]  Roemmich v. 3M, et. al., Slip Opinion, May 9, 2022 (Washington State Court of Appeals, Division One (published)).

[ii] The opinion also contains an interesting discussion of the interplay between ER 702 and the Frye standard for expert testimony.  The court indicated that expert testimony must satisfy both ER 702 and the Frye test.  Here, expert testimony failed to satisfy ER 702 was properly excluded without a Frye inquiry.  Slip Opinion, p. 18-20.

[iii] Roemmich, supra note 1 at 3.

[iv]  Mavroudis v. Pittsburgh-Corning Corp., 86 Wn. App. 22, 25, 935 P.2d 684 (1997).

[v] The court quoted Daugert v. Pappas, 104 Wn.2d 254, 260, 704 P.2d 600 (1985) for the proposition that “but-for causation required a physical connection between an act and an injury.  Slip Opinion, p. 9.

[vi] WPI 15.05 Proximate Cause—Supserseding Cause, 6 Wash. Prac., Wash. Pattern Jury Instr. Civ. WPI 15.05 (7th ed.).

[vii] Slip Opinion, p. 12.

[viii] 107 Wn.2d 807, 812-13, 733 P.2d 807 (1987).

[ix] 191 Wn. App. 284, 291, 361 P.3d 808 (2015).

[x] Slip Opinion, p. 17.


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