OPINION
In this toxic tort case alleging exposure to benzene, plaintiffs-appellants Sue and Ray Pluck appeal the district court’s order granting summary judgment to defendantappellee BP Oil Pipeline Company (“BP”). The Plucks challenge the district court’s grant of BP’s motion
in limine
to exclude the testimony of their specific-causation expert, Dr. James Dahlgren, as unreliable under
Daubert v. Merrell Dow Pharmaceuticals, Inc.,
I.
This case arose from benzene contamination allegedly caused by gas-pipeline releases near the Weaver Woodlands allotment in Franklin Township, Summit County, Ohio. Between 1948 and 1962, an underground pipeline owned by BP that passed through Franklin Township experienced five spills, resulting in the seepage of gasoline into the surrounding soil and groundwater. In 1990, following reports of drinking water contamination in Weaver Woodlands, BP entered into a voluntary agreement with the Ohio Environmental Protection Agency (“OEPA”) to investigate the source and extent of the contamination. Testing revealed the pres
In an effort to remediate the contamination, BP excavated areas of contaminated soil, constructed monitoring wells, and conducted ongoing soil and water testing in the area. BP conducted only a monitoring strategy with respect to 605 Fairwood, which had been designated as an “area of concern” because of its “hydraulically downgradient” position from 604 Fair-wood, where benzene contamination was present. In 1995, the owners of the property at 605 Fairwood sued BP for alleged contamination; BP agreed to purchase this property, and several others, in settlement. See Facemire v. BP Am., Inc., No. CV-1995-01-0159 (Summit Cnty. Ct. Common Pleas filed Jan. 13, 1995).
A.
In May 1996, Sue and Ray Pluck purchased the home at 605 Fairwood, where they used the well water to drink, wash, shower, and irrigate their yard and garden. In October 1996, around the time that the Plucks noticed a gasoline odor in their home and water, benzene was first detected in the well on their property in the amount of 3.6 parts per billion (“ppb”). 1 At this time, Mrs. Pluck began drinking bottled water in lieu of tap water, although she claims to have resumed drinking tap water upon the drilling of a new, deeper well. BP installed the new well in December 1996 and tested it on a quarterly basis; the company states, and the Plucks do not dispute, that between 1997 and May 2002, the new well tested negative for benzene twenty-two times. ' In October 2003, benzene measuring 1.8 ppb was detected in the new well, and a carbon filtration system was installed to capture the contaminant. In 2005, the Plucks moved from 605 Fairwood upon the recommendation of Mrs. Pluck’s physician.
Mrs. Pluck was diagnosed with NonHodgkins lymphoma (“NHL”) in 2002 at age forty-eight. Following chemotherapy in October 2002, the cancer went into remission for five years. Mrs. Pluck later experienced a recurrence in 2007 but was again in remission as of January 2009.
B.
The Plucks filed suit in the Summit County Court of Common Pleas on June 24, 2008, and BP thereafter removed the case to federal court.
2
See Pluck v. BP Am., Inc.,
No. 5:08-cv-01707 (N.D. Ohio removed July 16, 2008). On June 26, 2008, the Plucks filed a nearly identical suit in the United States District Court for the Northern District of Ohio, alleging claims of strict liability for hazardous activity,
To support their claims, the Plucks retained Drs. James Dahlgren and Joseph Landolph as experts on causation to demonstrate that benzene is generally capable of causing NHL and specifically caused Mrs. Pluck’s NHL. As to specific causation, Dahlgren opined in his report “to a reasonable degree of medical certainty that Sue Pluck’s [NHL] was caused or contributed to be caused by benzene from the BP refinery.” 3
On April 15, 2009, BP filed two 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 Dahlgren’s testimony 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.” BP also moved for summary judgment on the same date, arguing that, under Ohio law, “[without expert testimony to establish both general causation and specific causation, a claimant cannot establish a prima facie case of exposure to ... toxic substance[s].”
Terry v. Caputo,
On November 25, 2009, the district court issued an order granting all of BP’s motions and dismissing the Plucks’ case with prejudice. With respect to specific causation, the court rejected Dahlgren’s testimony as unreliable under
Daubert,
stating that it “suffered] significant -methodological flaws and [was] apparently based upon speculation and conjecture rather than evidence and data.”
4
The court premised its opinion on the following: Dahlgren formulated his opinion on dose “without any exposure data, only having been told that [Pluck] had been ‘heavily’ exposed to benzene in her water”; he relied upon a “no safe dose” theory that had been discredited by other courts as a basis for establishing specific causation; he could not explain the “scribbles” used to calculate Mrs. Pluck’s dose of benzene; and he filed an untimely supplemental declaration that contradicted his previous testimony and employed “an entirely new differential diagnosis methodology that was not mentioned at any point prior to the submission
II.
We “review the exclusion of expert testimony for abuse of discretion, even when the exclusion results in the entry of summary judgment for the opposing party.”
Meridia Prods. Liab. Litig. v. Abbott Labs.,
We review the district court’s grant of summary judgment
de novo. Allen v. Highlands Hosp. Corp.,
III.
The Plucks raise two arguments on appeal. They dispute the district court’s exclusion of Dahlgren’s specific-causation opinion as unreliable under Daubert, arguing that the court improperly demanded precise data regarding Mrs. Pluck’s dose of benzene and ignored Dahlgren’s differential-diagnosis methodology, which formed the basis of his opinion. The Plucks also challenge the district court’s exclusion of Dahlgren’s supplemental declaration, which was filed five months after the discovery deadline for expert reports. In response, BP contends that the district court properly excluded Dahlgren’s opinion, which failed to quantify Mrs. Pluck’s dose and “failed to account for confounding factors,” including other sources of benzene exposure. BP also maintains that the district court recognized differential diagnosis as a reliable methodology for establishing specific causation but concluded that Dahlgren employed this methodology in his untimely supplemental declaration only “after he had already arrived at his specific causation conclusion.”
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
Federal Rule of Evidence 702 governs the admission of expert testimony. It provides:
If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.
Fed.R.Evid. 702. In
Daubert,
the Supreme Court stated that the district court, when evaluating evidence proffered under Rule 702, must act as a gatekeeper, ensuring “that any and all scientific testimony or evidence admitted is not only relevant, but reliable.”
We have explained that
“Daubert
attempts to strike a balance between a liberal admissibility standard for relevant evidence on the one hand and the need to exclude misleading ‘junk science’ on the other.”
Best v. Lowe’s Home Ctrs., Inc.,
A.
The Plucks first argue that the district court improperly excluded Dahlgren’s specific-causation opinion based upon his failure to quantify Mrs. Pluck’s dose of benzene exposure. The Plucks concede that Dahlgren did not establish dose; they instead argue that Dahlgren used differential diagnosis to determine specific causation and that the district court “ignore[d] the ability of a physician to apply causal
This circuit has recognized differential diagnosis as an “appropriate method for making a determination of causation for an individual instance of disease.”
Hardyman v. Norfolk & W. Ry. Co.,
In this case, the Plucks acknowledge that Dahlgren did not explicitly identify differential diagnosis as his methodology until filing his supplemental declaration, but they argue that he identified and ruled out alternative causes for Mrs. Pluck’s NHL “without necessarily using the term ‘differential diagnosis.’ ” Yet, merely claiming that an expert used differential diagnosis is alone insufficient to satisfy the reliability inquiry under
Daubert. See Tamraz v. Lincoln Elec. Co.,
[c]alling something a “differential diagnosis” or “differential etiology” does not by itself answer the reliability question but prompts 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.
In
Tamraz,
we rejected an expert witness’s causation testimony, which sought to demonstrate that manganese exposure caused the plaintiffs Parkinson’s disease, as unreliable under
Daubert
and, therefore, inadmissible.
Id.
We stated that the expert’s opinion was unreliable because “his efforts to ‘rule in’ manganese exposure as a possible cause or to ‘rule out’ other possible causes turned on speculation, not a valid methodology.”
Id.
In particular, we observed that the expert’s hypothesis concerning the relationship be
Regardless of how the Plucks characterize Dahlgren’s causation analysis, his expert opinion likewise failed to meet the requirements of Rule 702. Foremost, Dahlgren could not reliably “rule in” benzene 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 whether she was exposed to quantities of benzene exceeding the EPA’s safety regulations. To the contrary, Dahlgren admitted that he “ha[d] limited exposure data” and that the “[r]esults of soil and water tests from the EPA for the Pluck’s [sic] property [were] still pending.” Nevertheless, he concluded that “chronic low-level exposure can and does cause NHL”; that Mrs. Pluck “probably had an injurious exposure to benzene and other organic solvents considerably above background”; and that “[t]here is no safe level for benzene in terms of causing cancer.” We find this analysis unpersuasive, particularly because 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 is not grounded in “sufficient facts or data,” nor does it reflect the “reliable principles and methods” required by Rule 702. It is, instead, pure conjecture.
Although the Plucks argue that the district court required too much specificity regarding Mrs. Pluck’s dose, this argument is without merit. In
Nelson,
we upheld the district court’s exclusion of a causation expert’s testimony in a case alleging injury due to exposure to polychlorinated biphenyls (“PCBs”) following a gas-pipeline release.
Although the Plucks contend that evidence of benzene exposure existed by virtue of its presence in their wells in 1996 and 2003, it is well-settled that the mere existence of a toxin in the environment is insufficient to establish causation without proof that the level of exposure could cause the plaintiffs symptoms.
See id.
at 252-53 (noting that the presence of PCBs in the plaintiffs’ environment “in excess of allowable limits” could not establish causation without evidence that they were “exposed at a level that could cause neurological and lung impairments”);
McClain v. Metabolife Int’l, Inc.,
In this case, Dahlgren acknowledged in his deposition that Mrs. Pluck was exposed to other sources of benzene, particularly from her extensive smoking habit. He observed that cigarettes contain benzene; that smoking can contribute to elevated levels of benzene exposure; and that he “[could not] tell from the existing data that her cigarette smoking would have caused her to be at significantly increased risk for ... [NHL].” Dahlgren also opined that other organic solvents may pose a risk, and his written opinion commented upon Mrs. Pluck’s “injurious exposure to benzene and other organic solvents.” Yet, Dahlgren neither identified these “other” solvents nor determined Mrs. Pluck’s potential level of exposure to them. Thus, Dahlgren failed to “rule out” alternative causes of Mrs. Pluck’s NHL, and the district court did not abuse its discretion in concluding that he did not perform a reliable differential diagnosis.
B.
The Plucks also argue that the district court erred in striking Dahlgren’s supplemental declaration, in which he used differential diagnosis to evaluate the cause of Mrs. Pluck’s NHL. Dahlgren filed his supplemental declaration on May 15, 2009 — one month after BP filed its
Daubert
motions and motion for summary judgment, and five months after the district court’s December 15, 2008, deadline for the submission of expert reports. The district court struck this declaration as untimely, contradictory to Dahlgren’s previous specific-causation opinion, and reliant
Although it is undisputed that Dahlgren first identified differential diagnosis as his causation methodology in his supplemental declaration, the Plucks maintain that Dahlgren used differential diagnosis in his deposition without explicitly saying so. They state that “Dahlgren was never asked in his deposition what his methodology was.” These statements approximate the Plucks’ argument in the district court, in which they relied upon
GED Integrated Solutions, Inc. v. Durotech International, Inc.
to argue that Dahlgren’s supplemental declaration should be admitted beyond the December 15, 2008, deadline for the submission of expert reports. No. 5:06CV 1327,
We have recognized that “[district courts have broad discretion to exclude untimely disclosed expert-witness testimony,” particularly when these reports serve as a “transparent attempt to reopen” the
Daubert
inquiry after the weaknesses in the expert’s prior testimony have been revealed.
Pride v. BIG Corp.,
IV.
For the foregoing reasons, we affirm the judgment of the district court in all respects. 6
Notes
. The EPA’s maximum permissible contaminant level for benzene is 5 ppb. 40 C.F.R. § 141.61(a)(2).
. The plaintiffs first filed these claims in the Summit County Court of Common Pleas in June 2006, after which the case was removed by BP to federal district court. On June 27, 2007, the parties stipulated to the dismissal of the claims without prejudice pursuant to Fed. R.Civ.P. 41(a). See Pluck v. BP Am., Inc., No. 5:06-cv-01444 (N.D. Ohio dismissed June 27, 2006).
. As there is no refinery near Weaver Woodlands, Dahlgren presumably is referring to the pipeline.
. The district court assumed "[f]or purposes of this analysis only,” that Landolph's testimony established general causation. It noted, however, that to the extent Landolph opined on specific causation, he relied "upon the purported methods and findings of Dahlgren.” On appeal, the Plucks challenge the district court's evidentiary rulings only with regard to Dahlgren.
. While plaintiffs typically must first establish general causation,
Terry,
. The Plucks claim in passing that the district court erroneously implied that Mrs. Pluck began drinking bottled water exclusively in 1996 and "ignored other avenues of exposure to benzene in the water — through dermal absorption and inhalation through showering, and through working the soil in her garden.” They argue that these alleged omissions "painted a picture” that their lawsuit involved merely an isolated incident of benzene exposure. However, contrary to this claim, the district court noted that the Plucks "used their well water to drink, wash, bathe, and irrigate their lawn and garden.” Moreover, although the district court correctly observed that Mrs. Pluck ceased drinking water from
