The insubstantiality of the "substantial factor" test for causation.

• Author: Sanders, Joseph
• Position: Symposium: A Tribute to Professor David Fischer

"Over the years, courts ... used the substantial factor test to do an increasing variety of things it was never intended to do and for which it is not appropriate. As a result, the test now creates unnecessary confusion in the law and has outlived its usefulness." (1)

1. FOR DAVID

   We are pleased and enthusiastic about participating in this effort to honor David Fischer and his remarkable career. Collectively, we have been consumers of his scholarship, colleagues who share an abiding interest in tort law, co-authors who have worked together with him on a Products Liability casebook, (2) and participants in Restatement projects (3) for which David has made contributions too numerous to catalogue.

   David's scholarship is most remarkable for the difficult problems he chooses to confront. His intellectual curiosity leads him into legal thickets that others have skirted. His work on the knotty and puzzling problems at the edge of causation--preemption, overdetermined outcomes, duplicated harm, and multiple omissions--takes on some of the most intellectually challenging areas that we confront. (4) David's work is painstaking, rigorous, thoughtful, persuasive, and helpful. He is also unflaggingly courteous and respectful in his work, even to those with whom he disagrees.

   Having had the opportunity to work directly with David on several editions of a Products Liability casebook for which he is originally responsible, we can affirm his thoughtfulness and carefulness in conceptualizing, developing, and organizing a text. Collaboration has been a pleasure, and David is always willing to take on more than his share, both in revising material and in handling the always burdensome logistics. Every collaborative project (and law school) needs good institutional citizens. David is the best.

   Finally, we applaud David's contributions to the Third Restatement of Torts project on Liability for Physical and Emotional Harm. (5) David has been among the most active participants on the Members Consultative Group. His scholarship on causation has been invaluable. Citations to his published work are liberally scattered throughout the Reporters' Notes. In particular, his work has revealed the wide-ranging impact "loss of chance" issues might have on other doctrines that previously were thought to be unrelated. He cautioned against failing to cabin this impact, and then provided guidance for appropriate mechanisms for imposing limits. (6) We have, on more than one occasion, sought and received his advice on a difficult issue. David is unflaggingly positive and supportive; he never feels the need for self-aggrandizement or self-promotion and always makes his considerable contributions in a graceful and unassuming manner.

   Because David's focus in his scholarly work has been on factual causation, and because he has contributed so much to our understanding of that subject in the Third Restatement, we have chosen a topic in that area for this essay. The essay addresses factual cause in toxic substances cases where the evidence of exposure is meager. (7) We're not sure that David will agree with all of what we say, but we hope that he will be honored by our choice of topic.

2. CAUSAL UNCERTAINTY IN ASBESTOS: DEFENDANTS NOT DISEASE

   The asbestos litigation is unique in American tort law. In a liability world increasingly occupied by mass torts, it is still "the mass tort that dwarfs all others." (8) Since the first successful asbestos case, Borel v. Fibreboard Paper Products Corp., (9) hundreds of thousands of personal injury claims have been brought, billions of dollars have been paid in claims and litigation costs, and numerous asbestos manufacturers, including Fortune 500 companies, have been driven into bankruptcy. (10) Although there is disagreement about where we are in the claims process, almost everyone agrees that the end of the asbestos cases is not in sight. (11)

   Throughout this long history, the asbestos litigation has presented a variety of fascinating causal questions. Many plaintiffs have benefitted (if that is the right word for it) from the fact that asbestos causes what are commonly called "signature diseases." (12) Asbestosis and mesothelioma are diseases that are unique or nearly unique to those who have inhaled asbestos fibers. (13) In other ways, however, proving causation in asbestos cases can be a daunting task. Many victims of asbestos-related diseases confront two related causal problems. First, due to the long latency period between exposure and manifestation for the most serious asbestos-related diseases, (14) plaintiffs often cannot identify specific defendants to whose products they were exposed. Second, even when the plaintiff does know the identity of some of the defendants, there is often no way to determine with any precision the level of exposure to each defendant's product and its contribution to the plaintiff's injury. (15) Depending on the biology of disease development, the extent of exposure, and when it occurred, exposure to a given defendant's product may have: 1) played no causal role in the plaintiff's disease; 2) contributed, along with exposure to other defendants' asbestos, to a dose sufficient to cause the plaintiff's disease (a "threshold dose"); 3) contributed, along with exposure to other defendants' asbestos, to a dose more than sufficient to cause the plaintiff's disease; 4) caused the disease independently of exposure to any other asbestos products; or 5) caused some marginally greater severity of plaintiff's disease. (16)

   Beginning with Borel, courts have attempted to deal with the causal uncertainty that exists, especially when the extent of exposure to a specific defendant's asbestos is uncertain, modest, or very small. (17) More recently, after some thirty years of asbestos litigation and decades of courts struggling with causal questions raised in other toxic substances cases, the Restatement (Third) of Torts: Liability for Physical and Emotional Harm has revisited the issue of causation. The Third Restatement, which each of us has been involved with, makes substantial changes to the causation provisions in the Second Restatement.

3. SUBSTANTIAL FACTORS AND SMALL EXPOSURES

   Against this backdrop, two recent state supreme court cases in Pennsylvania and Texas that confront the question of small or modest exposure to asbestos products provide an opportunity to assess the causal issues posed by such exposures. Both Gregg v. V-J Auto Parts, Inc. (18) and Borg-Warner Corp. v. Flores (19) rely on a substantial factor analysis to resolve the difficult causal question presented. We compare Gregg and Flores with two other cases, Lohrmann v. Pittsburgh Corning Corp. (20) and Rutherford v. Owens- Illinois, (21) that have addressed similar issues and have also relied on the concept of "substantial factor," contained in the Second Restatement of Torts. We argue, not surprisingly, that the best way to understand and resolve the complex causal questions posed in these cases is to employ the but-for test of causation as it is formulated in the Third Restatement of Torts. Although we are particular to conceptualizing causation as a but-for or necessary condition, we remain acutely aware of the difficulties of proof in toxic substances cases, including asbestos. We do, however, prefer confronting those difficulties head on rather than obscuring them with a substantial factor approach.

   Typically, plaintiffs sue every known entity to whose asbestos product they may have been exposed, and, during the course of discovery, some defendants may be dismissed by way of summary judgment or directed verdict if the plaintiff's contact with their product is too tenuous. Courts have been forced to develop a set of tests for judging which asbestos defendants are entitled to dismissal on this basis. The test developed in Lohrmann (22) is one popular solution to this problem. The trial court in Lohrmann granted directed verdicts to three defendants because there was insufficient evidence that plaintiffs came in contact with their products. The appellate court affirmed. It rejected the argument that if the plaintiff can prove that the defendant's asbestos containing product was at the workplace while the plaintiff was there, a jury question has been created as to whether the product was a cause of the plaintiff's disease. Instead, it concluded that "[t]o support a reasonable inference of substantial causation from circumstantial evidence, there must be evidence of exposure to a specific product on a regular basis over some extended period of time in proximity to where the plaintiff actually worked." (23) Some form of this test has been adopted by many courts. (24)

   The Lohrmann and similar tests have sometimes been used to prove exposure to asbestos in general and other times to prove exposure to a particular defendant's product. In nearly all of these cases, the courts conceive of the test as an instantiation of the Restatement (Second) of Torts Section 431's substantial factor test of causation. (25)

   In Gregg v. V-J Auto Parts, Inc., the Pennsylvania Supreme Court relied on the Lohrmann "frequency, regularity and proximity" test in a case brought by the survivors of a mesothelioma victim against an auto parts store where he had purchased asbestos-containing brake pads which he installed on his automobile. (26) Twice in the Gregg litigation the trial court entered summary judgment for the defendant because the evidence of exposure to the defendant's products was not sufficient to satisfy the plaintiff's burden of production. That is, employing the Lohrmann test, the plaintiff could not show that decedent's exposure to the defendant's product was a substantial factor in causing the illness. Twice the appellate court reversed the trial court's granting of a summary judgment.

   The decedent's exposure history is indeed quite sketchy. At one point, the plaintiff's expert averred that Mr. Gregg's illness was the result...