Confounding Variables: Expert Witness Uses Orange Study to Support Argument that Apples are Citric

Defendant-Appellant, Georgia-Pacific, has appealed from a judgment holding them liable for Mrs. Mahoney’s asbestos related disease and death. These injuries were allegedly caused by Mrs. Mahoney’s intermittent exposure to asbestos while helping her husband renovate houses in the 70’s. 

Plaintiff Joan Mahoney contracted mesothelioma allegedly from using asbestos-containing products in her family construction business. She and her husband, plaintiff Daniel Mahoney, sued numerous manufacturers of those products, including defendant Georgia-Pacific, LLC (GP). All defendants settled except GP, which opted to proceed to jury trial. The jury returned a verdict for plaintiffs for $20,050,000. The trial court reduced the verdict and entered judgment for $6,289,544.

Issue Areas:

Sound Science

Question(s) Presented:

Whether there was evidence presented at trial that Mrs. Mahoney’s exposure to chrysotile asbestos used by GP in its joint compound was the cause of Mahoney’s mesothelioma, or whether it was a substantial factor in bringing about the disease. 

ALF’s Amicus Brief:

Amici are concerned that the mere utterance of “asbestos” regardless of fiber type or exposure, combined with “mesothelioma” have had an undo impact on juries across the country. The verdict in this case should be overturned because Respondents failed to establish that Mrs. Mahoney’s exposure to chrysotile asbestos from the GP join compound caused her mesothelioma, as required by Rutherford v. Owens-Illinois, Inc. (1997) 16 Cal. 4th 953. Respondents assert that any “special exposure” is legally sufficient to cause mesothelioma. They failed to establish the extent of Mrs. Mahoney’s exposure, and failed to take into account the number of recent studies that show that chrysotile asbestos exposures much greater than Mahoney’s rarely if ever increase the risk of developing mesothelioma. The “special exposure” theory, which does not take into account of extent, frequency, or intensity of exposure, is just a repackaging of the theory rejected in Rutherford, and by numerous scientific papers, that any exposure to any type of asbestos causes mesothelioma.  

Respondents rely upon high-dose studies that looked at a different type of fibers that are indisputably more toxic than those that Mrs. Mahoney was allegedly exposed to. There is no study that supports the hypothesis that low-dose exposure to chrysotile fibers can cause mesothelioma. Because no studies support the opinions of Respondent’s expert, that opinion should have been excluded.

ALF shows that when compared to its toxic counterparts, chrysotile asbestos is nearly benign and that the low number of mesothelioma cases in highly exposed miners and millers was likely from confounding factors. ALF asks this Court to overturn the court below, and hold that evidence in these asbestos cases must relate to the correct fiber type. 


On October 7, 2009, the Court issued an adverse opinion.

Date Originally Posted: May 20, 2009

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