First Circuit Affirms Exclusion of Specific Causation Opinion

The First Circuit recently affirmed the exclusion of plaintiff's expert in a toxic tort claim, leading to summary judgment. See Milward v. Rust-Oleum Corp., No. 13-2132, 2016 WL 1622620 (1st Cir. 4/25/16).

Plaintiff Milward worked as a pipefitter and refrigerator technician for over thirty years. During the course of his employment, Milward was exposed to varying levels of benzene from paints and other products manufactured by (among others) Rust–Oleum Corporation. In 2004, he was diagnosed with Acute Promyelocytic Leukemia (“APL”). Three years later, Milward and his spouse sued Rust–Oleum.

To succeed against Rust–Oleum, the Milwards had the burden of establishing, through expert testimony, general and specific causation. In other words, they needed to show that exposure to benzene can cause APL (general causation), and that exposure to benzene was, in fact, a substantial factor in the development of Brian's APL (specific causation). The district court bifurcated the proceedings; it planned first to address the admissibility of expert testimony on general causation, and then to consider the specific causation issue.  

The issue on this appeal was specific causation. The Milwards retained occupational medicine physician Dr. Sheila Butler to serve as their expert witness, and the admissibility of her opinion testimony was at the heart of this appeal.  In her proposed testimony, Dr. Butler presented three theories.  First, she testified that although benzene is naturally occurring, there is no safe level of benzene exposure. This was her predominant theory, and she consistently reiterated her hypothesis. She emphasized that she reached this conclusion by examining “the biology, the pathophysiology, what the substance does to the person and the disease process.” And, she noted, she was able to do so without relying on any of the relevant epidemiological studies. Given this no-safe level theory, Dr. Butler maintained that Milward's exposure was likely the cause of his APL. The district court rejected this hypothesis because it could not be properly tested with any known rate of error. The Milwards did not meaningfully challenge the district court's conclusion on appeal.

Second, Dr. Butler rather cursorily concluded that even beyond the no-safe level hypothesis, certain epidemiological studies have established that an individual's “relative risk” of developing APL increases when exposed to specified amounts of benzene. She then compared Milward's exposure levels to those that had been found to be dangerous in that research. Since Milward's alleged exposure was higher than the amounts found to be hazardous, Dr. Butler reasoned that benzene exposure was likely the cause of his APL. Notably, she did not explain why she chose the studies on which she relied, nor did she address any study with contrary findings. In fact, during Dr. Butler's deposition, defendant's counsel asked her a number of questions about her ability and willingness to engage with the relevant epidemiological research. For instance, counsel asked, “Are you aware of any studies which find that there is no relationship between benzene exposure and APL,” to which she answered “Yes ... the literature has support for both.” Counsel then asked, “Do you intend in this case to weigh the different epidemiological studies and offer an opinion as to which ones we should rely on and which ones we should discount,” to which she replied, “No.”


Finally, Dr. Butler engaged in a so-called “differential diagnosis” to conclude that benzene exposure likely caused Milward's APL. Through this method (essentially a process of elimination) Dr. Butler “ruled out” some of the more common factors associated with APL, among them obesity and smoking. She then determined that since benzene exposure was a potential cause, she could also “rule out” an idiopathic diagnosis (or, a diagnosis without a known cause). Thus, since benzene exposure was the only significant potential cause remaining, she concluded that it was likely the culprit.

The court of appeals noted that it is NOT true that scientific studies must present diametrically opposing conclusions to be in tension with one another. Here, a number of studies were identified that showed a correlation between APL and benzene exposure at a specific level, while other studies do not show that correlation. In order to establish specific causation by the relative risk method, Dr. Butler was required to choose a study, or studies, to serve as a baseline to which she could then compare this case. There can be no serious question that choosing a study that showed a correlation above a specific level, rather than one that did not exhibit any such correlation, yields a vastly different comparison. The district court did not clearly err in finding that the studies were sufficiently distinct from one another such that utilizing one, rather than another, would necessarily lead to different testimony.  Generally, where an expert's medical opinion is grounded exclusively on scientific literature, a district court acts within its discretion to require the expert to explain why she relied on the studies that she did and, similarly, why she disregarded other, incompatible research. See, e.g., Kuhn v. Wyeth, Inc., 686 F.3d 618, 623–24 & 633 (8th Cir.2012) (permitting testimony where the expert witness relied on methodologically reliable studies and provided an explanation for why those studies were chosen); Norris v. Baxter Healthcare Corp., 397 F.3d 878, 886 (10th Cir.2005) (noting in the context of a general causation finding that the expert witness's inability to address contrary views made the opinion unreliable).

It is self-evident that, when an expert engages in a relative risk analysis in the manner that Dr. Butler did here, the district court is on firm ground in requiring such an explanation, since the validity of the approach depends on the reliability of the studies chosen. See 3 Mod. Sci. Evidence § 23:27 (2014–2015 Ed.) (discussing the use of the relative risk approach in establishing specific causation).  So, the district court reasonably ruled that there needed to be some indication of why Dr. Butler utilized the studies that she did. Indeed, her complete unwillingness to engage with the conflicting studies (irrespective of whether she was able to or not) made it impossible for the district court to ensure that her opinion was actually based on scientifically reliable evidence and, correspondingly, that it comported with Rule 702.

On the third issue, while a “differential diagnosis” can be a “reliable method of medical diagnosis: in some contexts, see Granfield v. CSX Transp., Inc., 597 F.3d 474, 486 (1st Cir.2010), an expert must still show that the steps taken as part of that analysis—the “ruling out” and the “ruling in” of causes—were accomplished utilizing scientifically valid methods. See Ruggiero v. Warner–Lambert Co., 424 F.3d 249, 254 (2d Cir.2005).  Since Dr. Butler was only able to “rule out” an idiopathic APL because she had “ruled in” benzene as a cause, the validity of her differential diagnosis turns on the reliability of that latter conclusion. See Ruggiero, 424 F.3d at 254 (noting that an expert must use reliable scientific methods to “rule in” causes); see also Best v. Lowe's Home Ctrs., Inc., 563 F.3d 171, 179 (6th Cir.2009); Glastetter v. Novartis Pharm. Corp., 252 F.3d 986, 989 (8th Cir.2001). Indeed, the reliability of that decision was particularly critical here given the extensive number of APL cases that are idiopathic. Under such circumstances, eliminating a number of potential causes—without properly and explicitly “ruling in” a cause—is simply “of little assistance.” Restatement (Third) of Torts; Phys. & Emot. Harm § 28, cmt. c(4)(2010).  

Dr. Butler “ruled in” benzene exposure solely by relying on her two other theories. But, both of these theories were unreliable. Given that the record did not contain a scientifically reliable basis to “rule in” benzene, Dr. Butler needed some other method to “rule out” an idiopathic diagnosis. She did not provide one. As such, the district court acted within its discretion to conclude that the extraordinary number of idiopathic APL cases, coupled with the lack of a reliable means to rule out an idiopathic diagnosis here, muted Dr. Butler's ability to reliably apply this methodology.

Once the district court excluded Dr. Butler's testimony, it then correctly granted Rust–Oleum's motion for summary judgment. As is well-established under Massachusetts law, “expert testimony is required to establish medical causation.” Reckis v. Johnson & Johnson, 28 N.E.3d 445, 461 (Mass.2015).

 

State Supreme Court Holds Causation Evidence Insufficient

The Vermont Supreme Court recently held that a plaintiff's evidence that exposure to benzene allegedly caused his cancer was insufficient to get to the jury.  Blanchard v. Goodyear Tire & Rubber Co.,  No. 2010-250 (Vt. 8/5/11).

Plaintiff was diagnosed with non-Hodgkin's lymphoma, and he attributed the onset of the disease to benzene exposure that allegedly occurred between 1968 and 1973 while he was a teenager playing on a ball field on the grounds of the former Goodyear rubber manufacturing plant. That  plant operated in Windsor, Vermont from 1936 to 1986. He sued, alleging that the field itself was polluted and that there was a gully in the outfield that transported foul-smelling and oily stormwater discharge away from the manufacturing plant.

Defendants moved for summary judgment. The lower court concluded that plaintiff was not entitled to present his case to a jury because he had provided insufficient evidence to support an inference that he had been exposed to benzene in any amount, let alone an amount that could have caused his illness, nor sufficient expert testimony sufficient to eliminate other potential causes of his disease. On appeal, plaintiff argued that his circumstantial evidence of causation was sufficient to present his case to the jury.

The state Supreme Court noted that the plaintiff could not survive the motion for summary judgment on his toxic tort claim unless he was able to point to evidence suggesting a probability, rather than a mere possibility, that (1) he was exposed to the specified chemical at a level that could have caused his physical condition (general causation); and (2) the exposure to that chemical did in fact result in the condition (specific causation).  In a toxic tort case, general causation addresses whether a substance is capable of causing a particular injury or condition in a population, while specific causation addresses whether a substance caused a particular individual's alleged injury. E.g., King v. Burlington Northern Santa Fe Ry. Co., 762 N.W.2d 24, 34 (Neb. 2009). General causation is typically shown through epidemiological studies, and plaintiffs in toxic exposure cases in Vermont generally must demonstrate specific causation by submitting evidence concerning the amount, duration, intensity, and frequency of exposure. Citing  Henricksen v. ConocoPhillips Co., 605 F. Supp. 2d 1142, 1157 (E.D. Wash. 2009) (citing several appellate court cases holding that experts testifying as to specific causation must pay careful attention to amount, intensity, and duration of exposure).

The court recognized that in some toxic tort cases it is impossible to quantify exposure with hard proof, such as the presence of the alleged toxic substance in the plaintiff's blood or tissue and the precise amount of the toxic substance to which an individual plaintiff was exposed. Plourde v. Gladstone, 190 F. Supp. 2d 708, 721 (D. Vt. 2002).  Therefore, expert testimony on toxic injuries may be admissible where dosage or exposure levels have been established through sufficient reliable circumstantial evidence. While it is not always necessary for a plaintiff to quantify exposure levels precisely, the courts generally preclude experts from testifying as to specific causation without having any some measurement or reasonable estimate of a  plaintiff's exposure to the allegedly harmful substance. Finally, a defendant's concession that its product contains a carcinogen, say benzene, does not excuse a plaintiff from having to show the benzene contained in defendant's product is capable of causing the illness at issue.

When direct evidence of the precise amount of exposure to a toxic substance is limited, some courts have allowed expert witnesses to use a differential diagnosis process as a method of proving specific causation. We have posted before about the mis-use and mischaracterization of this process.  Differential diagnosis is a scientific analysis entailing the weighing of relevant evidence, listing all likely explanations of the patient's observed symptoms or injury, then eliminating all but one.  Some courts have made the leap from allowing the process designed to arrive at a diagnosis (what disease caused the symptoms) to arrive at a cause (what substance caused the disease). However, said the state court, even the courts that do recognize differential diagnosis are reluctant to admit causation testimony based on a differential diagnosis where the proffered expert possesses only weak circumstantial evidence that some exposure occurred and makes insufficient effort to scientifically evaluate or estimate the degree of exposure or dosage. Also, and significantly, standing alone, the presence of a known risk factor is not a sufficient basis for ruling out idiopathic origin in a particular case, particularly where most cases of the disease have no known cause. In such cases, analysis beyond a differential diagnosis is required.

Here, plaintiff pointed to three bits of circumstantial evidence. First, he offered statements made by himself and boyhood friends concerning their alleged exposure to chemicals from the Goodyear plant when they were teenagers playing ball on a field adjoining the plant.  Second, plaintiff relied on the testimony of the project manager for an environmental firm hired by Goodyear in 2007 to conduct a site investigation in response to a clean-up agreement reached by Goodyear and the State of Vermont. The 2009 report stemming from the investigation listed contaminants of concern, including petroleum products containing benzene, that could have been released into the environment. Third, plaintiff relies upon the testimony of his two experts, who testified that occupational exposure to benzene is generally associated with a risk of non-Hodgkin's lymphoma, and that plaintiff's cancer was not caused by an immunodeficiency disorder, one of the known causes of that form of cancer.

That evidence "falls well short" of what plaintiff would be required to show in order to prevail in a jury trial. Indeed, if a jury were to find in favor of plaintiff on the evidence relied upon by plaintiff, said the court, "we would have to overturn the verdict." In the end, plaintiff's suspicion that his cancer was caused by exposure to benzene on the Goodyear ball field when he was a teenager was purely speculative. There was no way to know whether any benzene-containing product actually contaminated the ball field.  And there was no evidence indicating the amount or concentration of benzene that was present, even assuming some was. Nor was there any evidence indicating plaintiff's level of exposure to any benzene that may have been present on the field. Nor was plaintiff able to point to studies indicating a risk of cancer posed by exposure to limited amounts of benzene from petroleum products in an outside environment.  

Further, plaintiff could not rely upon differential diagnosis to overcome the complete lack of evidence as to the level of any exposure to benzene. A large percentage of cases of plaintiff's type of lymphoma are of unknown origin. Thus plaintiff's experts could not rule out all other causes, an essential part of the differential diagnosis.  E.g., Whiting v. Boston Edison Co., 891 F. Supp. 12, 21 n.41 (D. Mass. 1995) (concluding that differential diagnosis cannot be used to explain disease where 90% of cases of disease are of unknown origin).
 

Appeals Court Upholds Summary Judgment Based on Daubert in Benzene Case

The Sixth Circuit last week upheld the dismissal of a plaintiff''s claim that benzene exposure caused her cancer. Pluck v. BP Oil Pipeline Co., No. 09-4572 (6th Cir.,  5/12/11).  The central issue was the exclusion of plaintiff's causation expert's opinion based on a "differential diagnosis" that failed to reliably rule in benzene exposure as a potential cause of plaintiff's cancer, and to rule out some other potential exposures.

This case arose from benzene contamination allegedly caused by gas-pipeline releases allegedly resulting in the seepage of gasoline into the surrounding soil and groundwater. Benzene, a component of gasoline, is a known carcinogen in sufficient doses under certain exposure circumstances, and is also ubiquitous in the ambient air and is a component or constituent of vehicle exhaust and cigarette smoke, said the court. Plaintiffs purchased a home in the area,  and used well water to drink, wash, shower, and irrigate their yard and garden. In October,  1996, plaintiffs say they noticed a gasoline odor in their home and water, and benzene was first detected in the well on their property in the amount of 3.6 parts per billion (“ppb”).  They began drinking bottled water in lieu of tap water, although they claim to have resumed drinking tap water upon the drilling of a new, deeper well. Between 1997 and May 2002, the new well tested negative for benzene twenty-two times.

Mrs. Pluck was diagnosed with Non-Hodgkins lymphoma (“NHL”) in 2002 at age forty-eight. She filed suit, alleging claims of strict liability for hazardous activity, negligence, and loss of consortium. To support their claims, plaintiff and spouse retained Drs. Joseph Landolph and James Dahlgren as experts on causation to demonstrate that benzene is generally capable of causing NHL and specifically caused Mrs. Pluck’s NHL. Defendant filed motions in limine to exclude the testimony of Dahlgren and Landolph on the grounds that their testimony failed to satisfy the standard for reliability set forth in Daubert. In particular, BP argued that Dr. Dahlgren’s testimony on specific causation was unreliable because he formulated a specific causation opinion without evidence of dose, and subsequently performed an unreliable dose reconstruction in an attempt to support his opinion.  Dahlgren then submitted a supplemental declaration in which he evaluated Mrs. Pluck’s illness under a "differential-diagnosis" methodology. The district court granted the motions, and plaintiff appealed.

In a toxic tort case, as here, the plaintiff must establish both general and specific causation through proof that the toxic substance is capable of causing, and did cause, the plaintiff’s alleged injury.  As to specific causation, the plaintiff must show that she was exposed to the toxic substance and that the level of exposure was sufficient to induce the complained-of medical condition (based on a dose-response relationship). Both causation inquiries involve scientific assessments that must be established through the testimony of a medical expert. Without this testimony, a plaintiff’s toxic tort claim will fail.

The Plucks had to concede that the expert Dr. Dahlgren did not establish dose; they instead argued that Dahlgren used differential diagnosis to determine specific causation. Defendant argued that Dr. Dahlgren did not apply differential diagnosis in either his expert opinion or his deposition, but did so only in an untimely supplemental declaration filed five months after the deadline for expert reports. And in any event, his approach was flawed. The Sixth Circuit has recognized differential diagnosis, properly done, as an appropriate method for making a determination of causation for an individual instance of disease. Differential diagnosis -- originally a standard technique for determining what disease caused a patient's symptoms -- has been adapted in some courts as an acceptable scientific technique for identifying the cause of a medical problem by eliminating the likely causes until the most probable one is isolated. A physician who applies differential diagnosis to determine causation considers all ("rules in") relevant potential causes of the symptoms and then eliminates ("rules out") alternative causes based on a physical examination, clinical tests, and a thorough case history.

Even in courts that accept this adapted method, not every opinion that is reached via a differential-diagnosis method will meet the standard of reliability required by Daubert.  Calling something a “differential diagnosis” or “differential etiology” does not by itself answer the reliability question but prompts at least three more:

(1) Did the expert make an accurate diagnosis of the nature of the disease?

(2) Did the expert reliably rule in the possible causes of it?

(3) Did the expert reliably rule out the rejected causes?

If the court answers “no” to any of these questions, the court must exclude the ultimate conclusion reached.

Here the court agreed that Dahlgren could not reliably “rule in” benzene exposure as the cause of Mrs. Pluck’s NHL. In recognition of the fact that benzene poses a health concern at certain levels of exposure, the EPA has stated that the maximum permissible contaminant level for benzene in
drinking water is 5 ppb. 40 C.F.R. § 141.61(a)(2). Dahlgren, however, did not ascertain Mrs. Pluck’s level of benzene exposure, nor did he determine even whether she was exposed to quantities of benzene exceeding the EPA’s safety regulations. The levels of benzene in the Plucks’ wells never exceeded the maximum permissible contaminant level of 5 ppb designated by the EPA.

Dahlgren’s opinion that Mrs. Pluck’s “low-level exposure” to benzene caused her NHL was thus not grounded in “sufficient facts or data,”  nor did it reflect the “reliable principles and methods” required by Rule 702. It was, instead, pure conjecture.  Although the Plucks argued that the district court required too much specificity regarding Mrs. Pluck’s dose, this argument was also without merit. The mere existence of a toxin in the environment is insufficient to establish causation without proof that the level of exposure incurred could cause the plaintiff’s symptoms. See also McClain v. Metabolife Int’l, Inc., 401 F.3d 1233, 1242 (11th Cir. 2005) (causation “requires not simply proof of exposure to the substance, but proof of enough exposure to cause the plaintiff’s specific illness”).

Finally, even if Dr. Dahlgren had properly “ruled in” benzene exposure as the cause plaintiff's NHL, he failed to “rule out” alternative causes of her illness, as is required under the differential-diagnosis methodology. See also Wills v. Amerada Hess Corp., 379 F.3d 32, 50 (2d Cir. 2004) (expert’s opinion suffered from a “fatal flaw” when he acknowledged that cigarettes and alcohol were risk factors for developing squamous-cell carcinoma but failed to account for these variables in concluding that decedent’s cancer was caused by exposure to toxic chemicals such as benzene and PAHs).  In this case, Dahlgren acknowledged in his deposition that Mrs. Pluck was
exposed to other sources of benzene, from her extensive smoking habit and from other organic solvents.  Yet, Dr. Dahlgren neither identified these other solvents nor determined Mrs. Pluck’s potential level of exposure to these other possible sources of benzene.Thus, Dahlgren failed to “rule out” alternative causes of Mrs. Pluck’s NHL.

The court of appeals determined that the district court did not abuse its discretion in concluding that the expert did not perform a reliable differential diagnosis.  And summary judgment properly followed.

 

Court Excludes Toxic Tort Causation Testimony

A federal court has excluded plaintiffs' expert testimony in litigation alleging personal injury and property damage from releases at a Midwest refinery.  Baker, et al. v. Chevron USA Inc., et al., No. 05-cv-00227 (S.D. Ohio Jan. 6, 2010). In the absence of necessary expert testimony, the claims were subject to summary judgment.

Plaintiffs in this case were residents of the villages of Hooven and Cleves, Ohio, who asserted claims for personal injury and property damage allegedly resulting from the Gulf Oil refinery, now owned by defendant Chevron USA.  Gulf operated a gasoline refinery which was situated on the eastern edge of Hooven from 1930 to 1985. Gulf also refined diesel fuel, jet fuel, and fuel oil at the refinery and operated an asphalt plant at this location. Gulf and Chevron merged in 1985, and Chevron closed the refinery in 1986.

Plaintiffs alleged that Gulf’s operation of the refinery resulted in the release of millions of gallons of gasoline and diesel fuel.  But these plaintiffs did not claim injuries resulting from groundwater contamination. Rather, they asserted injuries allegedly caused by air emissions from the refinery and, in particular, the benzene contained in those emissions. Benzene is ubiquitous in the ambient air and is a component or constituent of vehicle exhaust and cigarette smoke. In the petroleum industry, benzene is found in small amounts in gasoline.

For case management purposes, the matter was bifurcated between personal injury claimants and property damage claimants. The parties were permitted to select bellwether plaintiffs for each trial group. This opinion dealt with the claims of the bellwether personal injury claimants, and a key issue, as is often the case in toxic tort litigation, was causation.

Regarding their alleged benzene exposure, plaintiffs offered a three-step procedure. First, expert Dr. Cheremisinoff calculated a gross amount of benzene released from the refinery through emissions. Then, using those calculations, Dr. Rosenfeld, plaintiffs’ second expert, used an air flow model to calculate the cumulative dose of benzene to which each plaintiff was exposed. Third, using those dose estimates, a third expert, Dr. Dahlgren, submitted opinions that each plaintiff’s dose of benzene was sufficient to cause her illness. 

Chevron moved to exclude Dr. Dahlgren's opinions under Daubert, and for summary judgment contingent  upon the striking of  plaintiffs' causation evidence. The principal argument raised was that Dr. Dahlgren’s opinions were unreliable because there was an insufficient scientific or medical basis to conclude that the doses of benzene to which plaintiffs’ were exposed were large enough to have caused their illnesses. Relatedly, Chevron contended that there is an insufficient scientific or medical basis to conclude that benzene even causes some of the illnesses alleged. The Court held a hearing on Chevron’s Daubert motion during which Dr. Dahlgren and Chevron’s medical expert also testified.

In a toxic tort case, the plaintiff must present evidence of both general causation and specific causation. General causation establishes whether the substance or chemical at issue is capable of causing a particular injury or condition. Specific causation relates to whether the substance or chemical in fact caused this plaintiff’s medical condition. Without expert medical testimony on both general causation and specific causation, a plaintiff’s toxic tort claim will fail.

In this case, Dr. Dahlgren offered causation opinions based largely on epidemiological studies. (Epidemiology is the study of the incidence, distribution, and etiology of disease in human populations.) Epidemiology is usually considered highly probative evidence on general causation in toxic tort cases. The court may nonetheless exclude expert testimony based on epidemiological studies where the studies are insufficient, whether considered individually or collectively, to support the expert’s causation opinion. Nothing in either Daubert or the Federal Rules of Evidence requires a district court to admit opinion evidence that is connected to existing data only by the ipse dixit of the expert. A court may thus conclude that there is simply too great an analytical gap between the data and the opinion proffered.

A couple of parts of the court's detailed analysis are worth highlighting for readers of  MassTortDefense:

First, Dr. Dahlgren’s reliance on the “one-hit” or “no threshold” theory of causation in which exposure to one molecule of a cancer-causing agent has some finite possibility of causing a genetic mutation leading to cancer. The court noted that while the one-hit theory has been accepted for purposes of establishing regulatory safety standards, it has not been accepted as a reliable theory for causation under Daubert standards.  See Allen v. Pennsylvania Eng’g Corp., 102 F.3d 194, 199 (5th Cir. 1996) (“Scientific knowledge of the harmful level of exposure to a chemical, plus knowledge that the plaintiff was exposed to such quantities, are minimal facts necessary to sustain the plaintiffs’ burden in a toxic tort case.”); McClain v. Metabolife Int’l, Inc., 401 F.3d 1233, 1240 (11th Cir. 2005) (holding that district court erred by not excluding plaintiff’s expert’s causation opinion because he neglected dose-response relationship); Henricksen v. ConocoPhillips Co., 605 F. Supp.2d 1142, 1162 (E.D. Wash. 2009) (excluding expert’s opinion pursuant to Daubert where “he presumed that exposure to benzene in gasoline can cause AML in any dose.”); National Bank of Commerce v. Associated Milk Producers, Inc., 22 F. Supp.2d 942, 961 (E.D.Ark. 1998), aff’d, 191 F.3d 858 (8th Cir. 1999); Sutera v. Perrier Group of Am., Inc., 986 F. Supp. 655, 667 (D. Mass.
1997). Moreover, since benzene is ubiquitous, causation under the one-hit theory could not be established because it would be just as likely that ambient benzene was the cause of plaintiffs’ asserted illnesses.

Second, the court noted that to the extent that Dr. Dahlgren relied on the evidence that plaintiffs were exposed to benzene in excess of regulatory levels, that is insufficient to make his opinions admissible. The mere fact that plaintiffs were exposed to benzene emissions in excess of mandated limits is insufficient to establish causation. Nelson v. Tennessee Gas Pipeline Co., 243 F.3d 244, 252-53 (6th Cir. 2001); David L. Eaton, Scientific Judgment and Toxic Torts- A Primer in Toxicology for Judges and Lawyers, 12 J.L. & Pol’y 5, 39 (2003) (“regulatory levels are of substantial value to public health agencies charged with ensuring the protection of the public health, but are of limited value in judging whether a particular exposure was a substantial contributing factor to a particular individual’s disease or illness.”). This is because regulatory agencies are charged with protecting public health and thus reasonably employ a lower threshold of proof in promulgating their regulations than is used in tort cases. Allen, 102 F.3d at 198.

Third, the court focused on the issue of the link between cited literature and the actual specific opinion given. The court recognized that an expert’s opinion does not have to be unequivocally supported by all epidemiological studies in order to be admissible under Daubert. But here, the opinions expressed in Dr. Dahlgren’s revised report were based "on a scattershot of studies and articles which superficially touch on each of the illnesses at issue." The expert had not differentiated the cases in any way and simply assumed that each reference supported his causation opinion on each and every illness. That clearly was not the case. Also, none of the cited studies supported an opinion that benzene can cause the illnesses from which plaintiffs suffer at the extremely low doses or exposures experienced in this case. Even if it is medically accepted that benzene can cause disease at high doses, Dr. Dahlgren could not cite any paper finding that the relevant low cumulative exposure significantly increases the risk of developing the injuries.

The court, therefore, found that the expert's causation opinions were not reliable under the standards enunciated by Daubert and, consequently, inadmissible. Without Dr. Dahlgren's testimony, the plaintiffs were unable to establish that their illnesses were caused by alleged emissions from the plant, the court observed, and so granted Chevron's motion for summary judgment on all four bellwether personal injury plaintiffs.
 

Summary Judgment In Benzene Case: Failure To Prove Dose

A federal court has granted summary judgment in a toxic tort suit in which plaintiff alleged he contracted a bone disease because of his long-term exposure to trace amounts of benzene in oil-based paint. Smolowitz v. The Sherwin-Williams Co., 2008 WL 4862981 (E.D.N.Y. Nov. 10, 2008). Plaintiff failed to offer sufficient evidence under New York law of exposure level.


In order to prevail in a toxic tort case, plaintiffs must present sufficient evidence to support a finding that defendants' products caused plaintiffs' injuries. Proof of causation requires establishing both “general” causation and “specific” causation.  General causation bears on whether the type of injury at issue can be caused or exacerbated by the defendant's product. Specific causation bears on whether, in the particular instance, the injury actually was caused or exacerbated by the defendant's product.  The fundamental principle of toxicology is that the dose makes the poison: substances that are benign or even beneficial at a certain level can be toxic at another. Even when general causation is clear, a plaintiff must show that he or she was exposed to a sufficient dose of the substance to have caused the disease. Under New York law, plaintiffs must establish both general and specific causation through expert testimony

Plaintiff Richard Smolowitz worked as a drywall taper and spackler over a thirty year period beginning in the 1950s and ending in the early 1980s. Plaintiff alleges that his exposure to benzene in paints caused him to contract myelodysplastic syndrome (“MDS”).  A central factual issue in this case, said the court, was the level of exposure to which plaintiff was subject, and whether that level of exposure can cause MDS. First, plaintiff was not a painter, but alleged he worked in areas where paint products were regularly used. Second, the solvents used in defendants' oil based paints contained only a trace contamination of benzene due to the fact that the products are based on petroleum, and it is not always possible to remove all of the benzene during the manufacturing process.

In early motion practice, plaintiff's counsel represented that he would provide the testimony of expert witnesses who could prove that plaintiff was exposed to oil based paints with sufficient levels of benzene to cause his illness. Eventually, he relied on the opinions of plaintiff's treating physician, Dr. Silverman, to provide expert testimony on issues of general and specific causation. The doctor reported he was currently treating plaintiff for MDS; that Smolowitz reported a history of exposure to oil based paints, thinners and benzene during a 35-year period; and that in his opinion it was “likely to a reasonable medical probability, that Mr. Smolowitz's exposure to benzene during the years that he worked as a dry-wall mechanic is causative for his current hematologic condition.”

The court concluded that Dr. Silverman's testimony was inadequate to prove either general or specific causation. The conclusory statement that based upon plaintiff's reported history it was likely to a reasonable medical probability that Mr. Smolowitz's exposure to benzene during the years that he worked as a dry-wall mechanic is causative for his current hematologic condition, had substantial deficiencies. First, there was nothing in this statement that suggests that Dr. Silverman was aware of or had quantified the precise amount of benzene to which plaintiff was exposed. No proof of dose. Second, Dr. Silverman did not offer any opinion as to whether that limited level of benzene exposure, whatever it was, can cause the disease. In the absence of sufficient evidence from an expert or a treating physician of the plaintiff's exposure level, plaintiff could not prove the essential causation element of the claim.
 

State Appeals Court Orders Venue Changes in Benzene Litigation

The Texas Court of Appeals ruled last week that a trial court had erred in denying the defendants' motion to transfer venue in a multi-plaintiff benzene lawsuit. Shell Oil Co. v. Baran, 2008 WL 2369030 (Tex.App.-Beaumont June 12, 2008).

Location, location, location – crucial factors in real estate and potentially in product liability litigation as well. While plaintiffs traditionally have the right to select the forum of their choice, such discretion is not unfettered. Venue rules, jurisdictional requirements, forum non conveniens, and removal possibilities, may all be considered by defendants to level the playing field.

The litigation in Baran involved the claims of multiple plaintiffs who sued more than 40 chemical and oil companies in Orange County, Texas, alleging they developed leukemia and other serious illnesses as a result of exposure to benzene, benzene-containing products, naptha, mineral spirits, petroleum distillates, methyl ethyl ketone, solvents, paints, primers, coatings, paint thinners, toluene and xylene. Among the specific injuries alleged were myelodysplastic syndrome, acute myelogenous leukemia and non-Hodgkin's lymphoma.

Plaintiffs filed a “Motion to Sever and Motion to Consolidate,” in which they asked the court to sever each plaintiff's claims into a separate proceeding, but to consolidate the cases for pre-trial discovery purposes only, which the trial court granted. But the trial court denied the defense motions to transfer venue as to each plaintiff. The moving defendants then filed an accelerated interlocutory appeal.

The court of appeals acknowledged that a plaintiff is generally permitted to choose venue first, and the plaintiff's choice of venue cannot be disturbed if the suit is initially filed in a county of proper venue. In Texas, however, in a suit with multiple plaintiffs, each plaintiff must, independently of every other plaintiff, establish proper venue.

Plaintiffs relied upon the general venue statute, which provides that suit shall be brought in the county where all or a substantial part of the events or omissions giving rise to the claim occurred or in the county where the defendant's principal office is located.  Plaintiffs alleged that all or a substantial part of the events giving rise to their cause of action occurred in Orange County, Texas, contending that each plaintiff alleged and offered prima-facie proof of a disease caused by cumulative exposures to defendants' benzene containing products, which resulted in each plaintiff's suffering an indivisible injury.  Because the injury was allegedly indivisible, plaintiffs argued, each arose out of the same transaction, occurrence, or series of transactions or occurrences even with multiple exposures.

Defendants specifically denied this allegation of venue, and the court agreed appellees provided insufficient facts to support this allegation, in their petition, or by way of affidavit or attachments supporting their same transaction or occurrence theory. In fact, plaintiffs did not plead this alleged venue fact in their original petition.

Plaintiffs’ other alleged basis for maintaining venue in Orange County was the allegation that DuPont had a principal place of business there. However, because plaintiffs sued multiple defendants, the trial court cannot maintain venue as to all of the other named defendants unless plaintiffs' claims arose out of the same transaction, occurrence, or series of transactions or occurrences. Again, plaintiffs argued that their claims arose out of the same transaction, occurrence, or series of transactions or occurrences because they suffered from indivisible injuries. But they had not pled adequate facts to conclude that their claims arose from the same transaction or occurrence. Thus, the trial court erred in concluding that plaintiffs independently established venue in Orange County.

When a plaintiff files suit in a county where venue is not proper, the defendant may have the suit transferred to a proper venue. Thus claims against ConocoPhillips Company, and several other defendants, were transferred to Harris County, Texas. The trial court was directed to transfer all of plaintiffs' claims and causes of action against Berryman Products, Inc. to Tarrant County, Texas, and to transfer all of plaintiffs' claims and causes of action against Safety-Kleen Systems, Inc. to Collin County, Texas, and so forth.

State Supreme Court Upholds Reversal of Benzene Verdict on Daubert Grounds

The Mississippi Supreme Court earlier today upheld the reversal of a $2 million benzene verdict. In Watts v. Radiator Specialty Co., et al., No. 2006-CA-01128-SCT (Miss. June 12, 2008), the Court's opinion focused on the absence of scientific evidence linking non-Hodgkin’s lymphoma, plaintiff’s condition, to benzene exposure.

Plaintiff alleged that his use of the product “Liquid Wrench” during his employment as a mechanic exposed him to benzene, and in turn caused his non-Hodgkin’s lymphoma. Plaintiff was diagnosed with small-cell lymphocytic lymphoma, a subtype of non-Hodgkin’s lymphoma in 1999. Liquid Wrench is a liquid solvent used for cleaning tools and engine parts and loosening nuts and bolts. Beginning in 1947, and throughout much of his career, Watts allegedly used Liquid Wrench as many as five times a day. It was undisputed that during at least 18 years of his usage Liquid Wrench did contain benzene.  In the 2004 trial, a jury found defendants Radiator Specialty and U.S. Steel liable.

In May 2006, however, the trial court granted the defendants’ motion for judgment notwithstanding the verdict after finding that the testimony of the plaintiff’s expert on the issue of causation should have been excluded as scientifically unreliable. Dr. Levy testified as to general causation (that benzene causes non-Hodgkin’s lymphoma) and specific causation (that benzene-containing Liquid Wrench caused Mr. Watts’s non-Hodgkin’s lymphoma). In particular, the trial court found that neither the cohort studies nor the case control studies relied upon by Dr. Levy at trial supported his opinion that a causal connection exists between benzene exposure and non-Hodgkin’s lymphoma. (Cohort studies identify and study a group of people exposed to a certain element as compared to another group not exposed to the element to see if there is a higher incidence of disease in the group exposed.; case-control studies identify and study a group of people who have a disease as compared to a group of people who do not have that disease to see if there is a higher incidence of exposure to a certain element in the group that has the disease.) The trial court entered an order dismissing the plaintiff’s case with prejudice, and the plaintiff appealed.

The State Supreme Court’s Analysis

The high court noted the defendants’ central contention that there is no evidence of a link between benzene exposure and small-cell lymphocytic lymphoma. The defendants claimed that Dr. Levy thus had insufficient support for his testimony that a demonstrable causal association exists between benzene exposure and non-Hodgkin’s lymphoma.

Mississippi follows the standard for expert testimony described in Daubert v. Merrell Dow Pharmaceuticals Inc., 509 U.S. 579 (1993). Trial judges are expected to assume the role of gatekeeper on questions of admissibility of expert testimony. There was no dispute that Dr. Levy was properly qualified as an expert in epidemiology and occupational medicine, but there was an issue regarding the reliability of his causation testimony.

The methodology used in forming his opinion as to general causation was the review of eighteen case studies done by different researchers between 1979 and 2004 (nine cohort studies and nine case-control studies). While this type of epidemiological study review is certainly an accepted methodology in the state, an analysis of these case studies supported the trial court’s finding that Dr. Levy’s testimony as to the content of the studies and their relevance to the facts of this case could easily have misled the jury. (The Court believed that juries are often in awe of expert witnesses and their impressive lists of honors, education and experience.)

Dr. Levy admitted that only half the studies showed a statistically significant increase in risk due to benzene exposure. None of the studies specifically looked at the possible risks associated with use of Liquid Wrench. None specifically studied the risks of development of non-Hodgkin’s lymphoma in mechanics, Watts’s profession. (The studied occupations included oil refinery workers, gas station attendants, general chemical workers, and seamen on tankers. ) One of the studies suggested that the reported increase in risk of non-Hodgkin’s lymphoma was not occupationally related. Several of the studies did not provide a dose-response ratio. In short, the Court believed, none of these studies provide a basis for the conclusion that there is a causal connection between benzene exposure and non-Hodgkin’s lymphoma, much less small-cell lymphocytic lymphoma, the particular type from which plaintiff suffered. The Court also emphasized the fact that the expert’s testimony gave very little detail, if any, as to the specific findings of each case study and why it might be relevant.

While experts need not rely on studies that explicitly support their testimony, it is significant that none of the studies relied upon by Dr. Levy found a conclusive link between benzene exposure and non-Hodgkin’s lymphoma.

Dissent Misses the Mark

Three justices in dissent disagreed with this conclusion, arguing that the trial court abused its discretion in excluding Dr. Levy’s testimony. Specifically, the dissent took issue with the emphasis on the conclusion that none of the studies found a link between benzene exposure and non-Hodgkin’s lymphoma. But the majority found it crucial that the few positive findings were not statistically significant, and/or did not relate to the relevant type of lymphoma, and/or that the higher risk of non-Hodgkin’s lymphoma was found among chemical workers who were exposed to a number of chemicals other than benzene and thus the observed risks could be due to some other exposure.

The Court drew upon the language of the United States Supreme Court in General Electric Co. v. Joiner, 522 U.S. 136 (1997), in which the Court observed that an expert’s conclusions and methodology are not entirely distinct from one another. Trained experts commonly extrapolate from existing data. But nothing in either Daubert or the Rules of Evidence requires a district court to admit opinion evidence which is connected to existing data only by the ipse dixit of the expert. A court may conclude that there is simply too great an analytical gap between the data and the opinion proffered.

The dissent also asserted that the majority’s decision would effectively resurrect the Frye standard requiring an expert’s opinion to be generally accepted in the scientific community. Frye v. United States, 54 App. D.C. 46, 47, 293 F. 1013, 1014 (1923). Quite to the contrary, this case is a good example of how courts should apply Daubert. Acceptance remains a relevant factor for trial courts to consider under Daubert. And the gap between the data and the conclusion was simply too great.

ATSDR Report on Benzene Impacting Litigation

The Agency for Toxic Substances and Disease Registry (ATSDR) issued a report on benzene a few months ago, and it has already begun to have an effect on the litigation.

ATSDR is an agency of HHS and is directed by congressional mandate to perform specific functions concerning the potential effect on public health of hazardous substances in the environment. These functions include public health assessments of waste sites, health consultations concerning specific hazardous substances, health surveillance and registries, response to emergency releases of hazardous substances, applied research in support of public health assessments, information development and dissemination, and education and training concerning hazardous substances.


A Toxicological Profile for Benzene, Draft for Public Comment was released in August 2005, and finalized in August, 2007. An ATSDR toxicological profile characterizes the toxicological and adverse health effects information for the hazardous substance at issue. They are peer-reviewed profiles, and each identifies and reviews the key literature that describes a hazardous substance's toxicological properties. Each profile is supposed to include the following:

(A) summary and interpretation of available toxicological information and epidemiological evaluations on a hazardous substance to ascertain the levels of significant human exposure for the substance and the associated acute and chronic health effects;

(B) determination whether adequate information on the health effects of each substance is available or in the process of development to determine levels of exposure that present a significant risk to human health; and

(C) identification of testing needed to identify the types or levels of exposure that may present significant risk of adverse health effects in humans.

The report notes that benzene, a colorless liquid with a sweet odor, evaporates into air very quickly and dissolves slightly in water. Benzene is found in air, water, and soil. Benzene comes from both industrial and natural sources. Benzene was first discovered and isolated from coal tar in the 1800’s. Today, benzene is made mostly from petroleum. Because of its wide use, benzene ranks in the top 20 in production volume for chemicals produced in the United States. Various industries use benzene to make other chemicals, used in plastics, resins, synthetic fibers. Benzene is also used in the manufacturing of some types of rubbers, lubricants, dyes, detergents, drugs, and pesticides. Natural sources of benzene include gas emissions from volcanoes and forest fires. Benzene is also present in crude oil and gasoline and cigarette smoke.


Everyone is exposed to a small amount of benzene every day, in the outdoor environment, in the workplace, and in the home. Exposure of the general population to benzene mainly occurs through breathing air that contains benzene. The major sources of benzene exposure are tobacco smoke, automobile service stations, exhaust from motor vehicles, and industrial emissions. Vapors (or gases) from products that contain benzene, such as glues, paints, furniture wax, and detergents, can also be a potential source of exposure. Auto exhaust and industrial emissions account for about 20% of the total national exposure to benzene. About half of the exposure to benzene in the United States results from smoking tobacco, according to the report. People living in cities or industrial areas are generally exposed to higher levels of benzene in air than those living in rural areas. Benzene levels in the home are usually higher than outdoor levels. For most people, the level of exposure to benzene through food, beverages, or drinking water is not as high as through air. Drinking water typically contains less than 0.1 ppb benzene. Benzene has been detected in some bottled water, liquor, and food.

Individuals employed in industries that make or use benzene may be exposed to higher levels of benzene. These industries include benzene production (petrochemicals, petroleum refining, and coke and coal chemical manufacturing), rubber tire manufacturing, and storage or transport of benzene and petroleum products containing benzene.

In an unpublished decision, the 5th Circuit relied on the ATSDR report to reverse the dismissal of a toxic tort case involving benzene. See Leblanc v. Chevron USA Inc., 2008 WL 1805448 (5th Cir. April 22, 2008).

Plaintiff alleged that after working as a tanker truck driver for over 30 years transporting products containing benzene, he was diagnosed with myelofibrosis with myeloid metaplasia-MMM, a rare disease. They tendered an expert who supported their claim that the exposure to benzene caused plaintiff's disease. Defendants challenged the expert testimony as unreliable under Daubert. The trial court excluded the testimony and, as is typically the case, because plaintiff had no other evidence on the critical causation issue, the case was dismissed.


At the time the district court issued its order, the ATSDR had issued the draft report on benzene. Because the report was still in draft form and the time for notice and comment had not expired when the district court issued its ruling, the trial court declined to consider it. During the pendency of the appeal, however, the draft received final approval. The Fifth Circuit noted that the ATSDR report on benzene was authored by a number of experts, was reviewed internally by the ATSDR, and peer reviewed by additional experts who collectively have knowledge of benzene's physical and chemical properties, toxicokinetics, key health end points, mechanisms of action, human and animal exposure, and quantification of risk to humans.


Moreover, in the report, the ATSDR concluded that benzene causes a life-threatening disorder called aplastic anemia in humans and animals. In describing a case report of a gasoline station attendant who had been exposed to benzene by inhalation, and probably also through dermal contact, the report calls myelofibrosis a form of aplastic anemia.

Because of this, and the “number and quality of the experts” who participated in the production of the final version of the ATSDR report, the 5th Circuit concluded that this report deserved the careful consideration of the district court before reaching a final conclusion on the reliability of plaintiffs’ expert testimony.

As readers of MassTortDefense interested in toxic torts will know, there is significant litigation surrounding benzene exposures. Some jurisdictions have consolidated cases for pre-trial coordination. E.g., In re: Benzene Litigation, No. 06C-BEN-1 (Del. Super. Ct., New Castle Cty.).

A week ago, a San Francisco jury reportedly awarded $8 million to a benzene plaintiff who claimed that his 17-year employment at SeaRiver Maritime Inc. exposed him to benzene, causing his kidney cancer. See Shelby v. Seariver Maritime Inc., f/k/a Exxon Shipping Co., No. CJC-06-449350 (Calif. Super. Ct., San Francisco Cty.). SeaRiver was the lone remaining defendant at the time of the trial.

Last month, several plaintiffs filed suit contending that they were wrongfully exposed to benzene while working at a Goodyear Tire Plant. Hauptmeier, et al., v. Barton Solvents Inc., et al., No. 08-187 (D. Neb.).

The litigation raises multiple important issues, including product identification, general and specific causation, and important procedural issues as well. In Anderson, et al. v. Crown Central LLC, et al., No. 08-0033 (Texas), plaintiffs are appealing the intermediate appellate court’s severance of their claims, Crown Central LLC v. Anderson, 239 S.W.3d 385 (Tex.App.-Beaumont,2007). Plaintiffs, as is common, prefer consolidated trials in their hand picked venue, with trial plans in which the best case (strongest plaintiff case) elevates the weaker plaintiff claims, despite the fact that often they cannot show their claims arose from the same transactions or occurrences.