California Appellate Court Allows Expert Opinion Testimony on “Every Exposure” Theory

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The plaintiff presented expert testimonial evidence at trial that her father’s exposure to asbestos from Bendix brake linings was a substantial factor in contributing to his risk of developing mesothelioma. The jury found in favor of the plaintiff; defendant Honeywell International appealed on two grounds: (1) the “every exposure” theory should have been excluded under California law, and (2) the trial court erred in refusing to give a supplemental jury instruction regarding factors relevant to the substantial factor determination. The court found no error.

For approximately 15 years, the decedent did one or two brake jobs per day, and two or three home remodeling projects per month with drywall and tile. Before trial, Honeywell filed motions in limine to preclude the plaintiff from presenting expert testimony that every exposure to asbestos above background levels contributed to mesothelioma; this motion was denied and the court allowed Dr. James Strauchen, pathologist, to testify.

On appeal, Honeywell argued that this opinion was: (1) speculative and illogical; (2) the regulatory standards he relied upon could not establish causation; (3) no appropriate scientific literature supported this theory and epidemiological studies contradicted it; and (4) the theory was contrary to California causation law. The court addressed each argument: (1) it is not illogical to conclude that each exposure, when added to other exposures, could result in a cumulative exposure above background levels; (2) Dr. Strauchen did not rely on regulatory standards to develop his opinion because he did his own research; (3) Dr. Strauchan did not admit there were no low dose studies, and in fact low dose studies did exist; and (4) California law did not require a dose level estimation, but a determination to a reasonable medical probability that the exposure was a substantial factor. Although other jurisdictions have rejected this theory, California had different standards from other jurisdictions. The court stated: “Finally, we simply disagree with courts in other jurisdictions that conclude the ‘every exposure’ theory cannot be reconciled with the fact that mesothelioma and other asbestos-related diseases are dose dependent.”

Lastly, there was no error in refusing to give Honeywell’s proposed jury instruction on causation; California law did not require the causation factors listed by Honeywell in the proposed instruction.

Read the full decision here.