Markle, Judge. Luther Bowers was an employee of CSX Transportation, Inc. for more than 30 years, during which he was continuously exposed to diesel fuel and exhaust, asbestos, and silica dust. After learning that he had terminal lung cancer, he filed suit against CSX under the Federal Employers’ Liability Act (FELA), 45 USCA § 51 et seq., alleging that the railroad company’s negligence in handling toxic substances, and its failure to warn him of the dangers, caused or contributed to his lung cancer.[1] In support of his claim, and to establish causation, Bowers offered the expert testimony of Dr. Theron Blickenstaff, a physician board-certified in preventative and occupational medicine. CSX moved to exclude Blickenstaff’s testimony under OCGA § 24-7-702 (“Rule 702″), and moved for summary judgment on the ground that Luther failed to establish causation. Following a hearing, the trial court granted the motion to exclude, and having excluded the causation expert, the trial court granted CSX’s motion for summary judgment. Bowers now appeals, arguing that the trial court erred by excluding Blickenstaff’s expert testimony because it misapplied Rule 702. For the reasons that follow, and applying the deference we are required to give the trial court’s findings in its role as gatekeeper under Rule 702, we affirm. “Whether expert testimony ought to be admitted under OCGA § 247702 is a question committed to the sound discretion of the trial court, so we will not disturb the trial court’s determination absent an abuse of discretion.”[2] (Citation and punctuation omitted.) MyFamilyDoc v. Johnston, 366 Ga. App. 459, 464 (2) (883 SE2d 404) (2023). So viewed, the record shows that Luther worked for CSX for more than 30 years in numerous capacities, including as a trackman, track inspector, machine operator, and road master. In these positions, he built and repaired railroads, which resulted in frequent exposure to diesel fuel and exhaust, asbestos, and silica dust. Luther was also a lifelong smoker, averaging multiple packs a day for 50 years. After he retired from CSX, Luther was diagnosed with terminal lung cancer. He then filed suit against CSX, and submitted Blickenstaff’s testimony to establish that his exposure to toxins while working for CSX was the cause of his cancer. Blickenstaff explained that exposure to diesel fuel and exhaust, asbestos, and silica dust causes lung cancer.[3] To determine whether these toxins caused Luther’s specific cancer, Blickenstaff relied on a report provided by Dr. Vance, an industrial hygienist who was involved in Luther’s case. Based on Luther’s testimony in his deposition and conversations with Luther’s co-workers, Vance concluded that Luther had been exposed to more than background levels of diesel fuel and exhaust, asbestos, and silica, and that these toxins, combined with Luther’s smoking, “multipl[ied]” the risk he would develop cancer. According to Blickenstaff, it was a “reasonable assumption” that exposure to these toxins contributed to Luther’s lung cancer, as any exposure to toxic substances increases the risk of cancer. In support, he pointed to seven studies, four of which linked cancer to exposure to these toxins. Blickenstaff then explained that he made a differential diagnosis, considering all of Luther’s risk factors and concluding that the occupational exposures and smoking were significant and made it highly unlikely there was any other cause. He opined that the exposure to the toxins while working for CSX increased Luther’s risk of getting cancer and thus caused his cancer to a reasonable degree of medical certainty. Although he reached this conclusion, Blickenstaff admitted that he was unable to confirm the level of exposure that would be necessary to cause lung cancer, how much toxin Luther was exposed to, or how that quantity compared to the exposures in the various studies he relied on. Blickenstaff noted that CSX had never conducted any air quality studies to determine the amount of exposure. Blickenstaff also could not identify the various jobs Luther held and could not link the amount of exposure to any specific railroad work. He further admitted that most people exposed to diesel fuel and exhaust do not get lung cancer. Despite his opinion that Luther’s exposure to the toxins caused his cancer, Blickenstaff acknowledged that a reasonable scientist could find that Luther’s smoking contributed more to cancer than the diesel exposure, and he conceded that it was possible that smoking was the only cause of Luther’s cancer. CSX moved to exclude Blickenstaff’s opinion and for summary judgment. Following a hearing, the trial court excluded the testimony because it did not meet the standard for admissibility under Rule 702, and granted summary judgment to CSX. Bowers now appeals, arguing that the trial court erred by granting these motions. According to Bowers, his expert was not required to quantify the exact amount of exposure necessary to cause cancer, or the amount to which Luther was exposed, especially given that CSX never performed air quality measurements. Bowers further challenges the trial court’s rejection of the expert’s differential diagnosis and reliance on various studies, arguing that the trial court focused on the results rather than the methodology. Finally, Bowers argues that the trial court applied the wrong legal standard by concluding that the testimony would not be helpful to the jury. Before we consider the admissibility of the expert’s testimony, we begin by setting out the general standard for liability in FELA cases. “Under FELA, railroad companies are liable for injuries to their employees that result in whole or in part from company negligence. . . .” (Citations and punctuation omitted.) Keen v. Ga. Southern & Fla. R. Co., 354 Ga. App. 787, 788-789 (1) (840 SE2d 529) (2020). To bring a claim under FELA, a plaintiff must prove the traditional common law elements of negligence: duty, breach, foreseeability, and causation. Whether the defendant has a duty to the plaintiff is a question of law to be decided by the court. The other three elements foreseeability, breach, and causation are questions of fact to be decided by a jury, assuming that there is evidence in the record creating a genuine issue for trial. (Citation and punctuation omitted.) Id. at 789 (1). The causation element in a toxic tort case requires the plaintiff to “prove both general causation, that a substance is capable of causing a particular injury or condition, and specific causation, that a substance made a meaningful contribution to a particular individual’s injury.” (Citations omitted.) Wadley v. Mother Murphy’s Laboratories, 357 Ga. App. 259, 263 (1) (850 SE2d 490) (2020). CSX does not challenge the testimony as to general causation. Thus, the only issue is whether Blickenstaff’s testimony was admissible to show specific causation. It is well-settled that the standard of proof as to causation in a FELA case is relaxed, and a plaintiff need only show that the employer’s negligent conduct “played any part, even the slightest” in causing the injury. (Citation and punctuation omitted; emphasis in original.) Keen, 354 Ga. App. at 789 (1); Smith v. CSX Transp., 343 Ga. App. 508, 510 (1) (a) (806 SE2d 890) (2017). But, the standard for admitting expert testimony is the same in a FELA case as it is in any other tort case; a plaintiff must still come forward with admissible expert testimony on specific causation.[4] Smith, 343 Ga. App. at 510-511 (1) (a); see also Shiver v. Ga. & Fla. Railnet, 287 Ga. App. 828, 829 (1) (652 SE2d 819) (2007) (“in a FELA case involving allegations of injury due to chemical exposure, the plaintiff must show specific causation through expert testimony.”); Wills v. Amerada Hess Corp., 379 F3d 32, 47 (III) (B) (2d Cir. 2004) (“[t]he standards for determining the reliability and credibility of expert testimony are not altered merely because the burden of proof is relaxed. . . . [I]n the context of FELA claims, the standard of causation and the standards for admission of expert testimony under the Federal Rules of Evidence are distinct issues and do not affect one another.”) (citation and punctuation omitted). Therefore, even in a FELA case, the admissibility of expert testimony is governed by Rule 702, which requires that “(1) it is based upon sufficient facts or data; (2) it is the product of reliable principles and methods; and (3) the expert witness has applied the principles and methods reliably to the facts of the case.” Emory Univ. v. Willcox, 355 Ga. App. 542, 543 (1) (844 SE2d 889) (2020) (citing Rule 702 (b)).[5] Under [Rule 702], it is the role of the trial court to act as a gatekeeper of expert testimony. In this role, the trial court assesses both the witness’[s] qualifications to testify in a particular area of expertise and the relevancy and reliability of the proffered testimony. [This is a] “rigorous threepart inquiry” in which the trial court considers whether: (1) the expert is qualified to testify competently regarding the matters he intends to address; (2) the methodology by which the expert reaches his conclusions is sufficiently reliable . . . ; and (3) the testimony assists the trier of fact, through the application of scientific, technical, or specialized expertise, to understand the evidence or to determine a fact in issue. (Citations and punctuation omitted). Id. at 543 (1); see also Daubert v. Merrell Dow Pharmaceuticals, 509 U. S. 579 (113 SCt 2786, 125 LE2d 469) (1993). In making this assessment, however, the trial court may not exclude an otherwise sufficient expert opinion simply because it believes that the opinion is not — in its view — particularly strong or persuasive. The weight to be given to admissible expert testimony is a matter for the jury. . . . [V]igorous crossexamination, presentation of contrary evidence, and careful instruction on the burden of proof are the traditional and appropriate means of attacking shaky but admissible evidence. . . . (Citations and punctuation omitted.) Willcox, 355 Ga. App. at 543-544 (1). Nevertheless, the trial court, in the exercise of its discretion, has “considerable leeway in deciding which tests or factors to use to assess the reliability of an expert’s methodology.” (Citation and punctuation omitted.) Smith, 343 Ga. App. at 512 (1) (b). As we recently explained, “[t]rial courts must determine whether to allow expert opinions on a casebycase basis.” (Citation and punctuation omitted.) MyFamilyDoc, 366 Ga. App. at 465 (2). And, even in a FELA case, speculative medical testimony is not admissible . . . . [The] medical expert must be able to articulate that it is likely that the defendant’s negligence, or more than possible that the defendant’s negligence, had a causal relationship with the injury and disability for which the plaintiff seeks damages. Mayhew v. Bell SteamShip Co., 917 F2d 961, 964 (6th Cir. 1990). Here, CSX does not challenge Blickenstaff’s qualifications. It contends only that his methodology is unreliable, and thus his testimony would not be helpful to the jury. The trial court rejected Blickenstaff’s opinion because: (a) his methodology was unreliable, as he did not adequately analyze the studies; and (b) he failed to reliably rule out Bowers’s smoking as part of his differential diagnosis.[6] After a thorough review of the record, and mindful of our deferential standard of review, we are constrained to conclude that the trial court did not abuse its discretion by excluding Blickenstaff’s testimony. (a) Reliable methodology. The trial court rejected Blickenstaff’s opinion because he failed to show how the various studies on which he relied applied to Luther’s case, rendering his methodology unreliable. We agree. Blickenstaff explained that he looked at multiple studies and pooled the data from those studies to get statistically significant results, from which he concluded that the exposure contributed to Luther’s lung cancer. But he acknowledged that the pooled data did not involve solely railroad workers. He then pointed specifically to seven studies that did involve railroad workers, four of which identified a relationship between exposure and cancer, and three of which did not. These studies characterized various railroad jobs and addressed the potential exposure for each one. But Blickenstaff testified that he could not determine how Luther’s jobs compared to those cited in the studies, stating instead that the exposure rate “may” be similar. He acknowledged that the studies likely involved older machinery, and newer equipment like that presumably used during the time Luther was working, would have lower exposure levels. He further admitted that he did not have sufficient details to determine whether Luther’s exposure was similar to those cited in the studies. Instead, Blickenstaff made assumptions regarding the amount of exposure in order to draw comparisons to the studies. Because he could not explain how the information in those studies could be applied to Luther’s case, especially given his inability to determine whether the positions in which Luther worked corresponded with the ones cited in the studies, the trial court did not abuse its discretion in finding Blickenstaff’s reliance on these studies unreliable. Mayhew, 917 F2d at 964 (finding speculative testimony inadmissible). Moreover, Blickenstaff’s opinion based on these studies often conflated general and specific causation. He stated that it was unnecessary to connect Luther’s specific jobs to his level of exposure because the literature had already established a link between exposure and cancer. But this response goes to general causation, which is not in dispute, and should not be equated with specific causation. It is one thing to say exposure could cause cancer, but quite another to say that it did. See Smith, 343 Ga. App. at 514 (1); Lancaster v. BNSF R. Co., 564 FSupp.3d 823, 833 (D. Neb. 2021) (“But to opine that a particular substance could have been a cause of lung cancer is simply to testify to general causation—that is, to opine that the substance is cancerous. An opinion on specific causation requires testimony, to a reasonable degree of medical certainty, that a substance did cause the harm alleged.”) (emphasis in original). [A]n expert cannot simply assert that an employee was exposed to some unknown amount of a potential carcinogen, and some unknown amount of that potential carcinogen can cause cancer, so therefore exposure to that carcinogen did cause the employee’s cancer: that’s just the type of opinion that is connected to the data only by the ipse dixit of the expert, and need not be accepted by the Court. (Citation and punctuation omitted; emphasis in original.) Lancaster, 564 FSupp.3d at 832. Perhaps even more glaring, Blickenstaff could not explain why he credited the four studies linking cancer to railroad workers’ exposure to toxins and rejected the three studies that did not, even though he conceded that those three studies took smoking into consideration. He further acknowledged that the four studies he credited showed only a weak association between exposure and cancer. To explain how he reached his conclusion, Blickenstaff said only that he focused on the totality of the evidence, which included consideration of studies involving non-railroad workers. He further explained that he relied on the IARC’s evaluation of the various studies in reaching his conclusions, which again relates more to general causation than it does to specific causation. Thus, we cannot say that the trial court abused its discretion in finding this testimony insufficient to establish specific causation under Rule 702. See Kilpatrick v. Breg, Inc., 613 F3d 1329, 1336-1340 (IV) (A) (11th Cir. 2010) (considering various studies in general causation analysis and finding expert’s testimony speculative and unreliable). (b) Differential diagnosis. Even if we were to conclude the trial court abused its discretion in evaluating Blickenstaff’s methodology, which we do not, the trial court was still within its discretion to reject his testimony based on his differential diagnosis. A differential diagnosis is a “method by which a physician determines what disease process caused a patient’s symptoms. The physician considers all relevant potential causes of the symptoms and then eliminates alternative causes based on a physical examination, clinical tests, and a thorough case history.”[7] (Citation omitted.) Shiver, 287 Ga. App. at 829 (1). Here, Blickenstaff opined that it was “theoretically possible that [Luther] would not have developed lung cancer had it not been for his occupational exposure.” Blickenstaff acknowledged Luther’s decades of smoking, and stated that the risk of lung cancer is generally higher from smoking than it is from exposure to toxins, yet he concluded that it was “unlikely” smoking was the sole cause. Instead, he attributed Luther’s cancer to the exposure, and when asked “[h]ow confident are you in your opinion that asbestos exposure at the railroad contributed to [Luther's] lung cancer?” Blickenstaff responded, “I think it’s a reasonable assumption.” But this assumption is inconsistent with his admission that most people exposed to toxins do not get lung cancer. Blickenstaff made assumptions that the exposure contributed to Luther’s lung cancer, while at the same time he acknowledged that smoking could be a contributing factor, yet he offered no explanation for why he ruled it out as the sole cause of Luther’s cancer. Instead, he stated only that he did not have to “commit to just one possibility.” He further conceded that smoking was a substantial risk for getting lung cancer, and it was possible smoking was the sole cause of Luther’s cancer, as most people exposed to these toxins did not develop lung cancer. As the trial court found, this differential diagnosis falls short of what is required under Rule 702, and Blickenstaff’s refusal to rule out smoking renders his differential diagnosis unreliable. See Shiver, 287 Ga. App. at 829 (1); see also Smith, 343 Ga. App. at 515-516 (1) (explaining that differential diagnosis is not admissible where trial court finds expert did not apply method reliably); Guinn v. AstraZeneca Pharmacueticals, 602 F3d 1245, 1253 (III) (A) (1) (11th Cir. 2010) (“an expert must provide a reasonable explanation as to why he . . . has concluded that any alternative cause suggested by the defense was not the sole cause of the plaintiff’s injury”) (citations and punctuation omitted); Lancaster, 564 FSupp.3d at 832 (expert’s refusal to rule out smoking as the sole cause of the plaintiff’s cancer rendered his differential diagnosis insufficient to establish specific causation); McLaughlin v. BNSF R. Co., 439 FSupp.3d 1173, 1182 (III) (D. Neb. 2020) (expert’s differential diagnosis was insufficient where he failed to rule out smoking as sole cause of cancer); compare MyFamilyDoc, 366 Ga. App. at 465 (2) (differential diagnosis sufficient where expert considered other diseases that could have caused death and explained why he ruled in the specific condition as the cause of death and ruled out the other medical conditions). As a result, the trial court properly discounted Blickenstaff’s differential diagnosis. Smith, 343 Ga. App. at 513 (“In deciding whether an expert employed a reliable method, the trial court has discretion to consider whether the expert has adequately accounted for obvious alternative explanations.”) (citation and punctuation omitted); see also Pluck v. BP Oil Pipeline Co., 640 F3d 671, 680 (III) (A) (6th Cir. 2011) (trial court properly excluded expert where differential diagnosis failed to rule out smoking as a cause of plaintiff’s cancer); Mayhew, 917 F2d at 963 (“[A]lthough a [FELA] plaintiff need not make a showing that the employer’s negligence was the sole cause, there must be a sufficient showing (i.e. more than a possibility) that a causal relation existed.”). In summary, when we apply our deferential standard of review and give the trial court the “leeway” we must in its role as gatekeeper, we cannot say the trial court abused that discretion, even if we might have reached a different decision.[8] General Elec. v. Joiner, 522 U. S. 136, 143 (II) (118 SCt 512, 139 LE2d 508) (1997) (“deference . . . is the hallmark of abuseofdiscretion review”); Willcox, 355 Ga. App. at 545 (2); Williams v. State, 328 Ga. App. 876, 880 (1) (763 SE2d 261) (2014) (review under abuse of discretion standard recognizes that there is a “range of possible conclusions the trial judge may reach” and we will affirm a trial court’s decision “even though we would have gone the other way had it been our call”) (citation and punctuation omitted); McDonald v. Garden Svcs., 163 Ga. App. 851, 852853 (295 SE2d 551) (1982) (unless there has been an abuse of discretion, this Court will not substitute its judgment for the trial court’s, even if individual judges might have reached a different conclusion); United States v. Pon, 963 F3d 1207, 1219 (III) (A) (11th Cir. 2020) (“The deference we show trial courts on evidentiary rulings is especially pronounced in the Daubert context, where the abuse of discretion standard places a heavy thumb — really a thumb and a finger or two — on the [trial] court’s side of the scale.”) (citation omitted). We simply cannot substitute our own judgment for that of the trial court, which is tasked with evaluating the expert’s opinion under Rule 702. To conclude otherwise would essentially usurp the trial court’s role as gatekeeper. Accordingly, we affirm the trial court’s exclusion of the expert testimony and its grant of summary judgment. Judgment affirmed. Rickman, J. , concurs. Doyle, P.J. concurs fully in division (a) and concurs in judgment only in division (b). Mercier, C. J., Barnes, P. J., Dillard, P. J., Brown, Land, and Watkins, JJ. , concur in judgment only. Miller, P. J., McFadden, P. J., Hodges, and Pipkin, JJ., and Senior Judge C. Andrew Fuller, dissent. In the Court of Appeals of Georgia A23A0839. BOWERS v. CSX TRANSPORTATION, INC. McFadden, Presiding Judge, dissenting. Torts involving multiple contributing causes, particularly toxic torts, are different from torts with a single cause. That difference is recognized in the proof required of toxic tort claims involving multiple toxins. See In re Meridia Products Liability Litigation, 328 FSupp2d 791, 798 (I) (N.D. Ohio 2004). The majority opinion overlooks that difference and in doing so overlooks the difference between a gatekeeper and a fact finder. So I respectfully dissent. 1. Facts The expert testimony the majority would exclude is that of the plaintiff’s medical expert, Dr. Theron Blickenstaff. Blickenstaff relied on — and as authorized by OCGA § 247703 assumed the accuracy of — the investigative report prepared by Bowers’s other expert witness, industrial hygienist R. Leonard Vance as well as a deposition given by Luther Bowers himself, shortly before his death. Blickenstaff reached his specific causation opinion after applying a differential diagnosis. “Differential etiology, or differential diagnosis, is a technique to identify the cause of an illness or condition by identifying common causes of the symptoms or diagnosis at issue and then, onebyone, ruling out causes until the most probable one is isolated.” Sarkees v. E. I. Dupont De Nemours & Co., 15 F4th 584, 589, n.8 (2d Cir. 2021) (citation and punctuation omitted). In ruling in Bowers’s exposures as specific potential causes, Blickenstaff applied the Bradford Hill criteria, a widely accepted set of criteria for determining causation in cases of chronic disease. The Bradford Hill criteria are an epidemiological study approach employed to assess when an association can truly be deemed causal. In re Lipitor (Atrovastatin Calcium) Mktg., Sales Practices and Products Liability Litigation, 892 F3d 624, 638 (II) (A) (2) (B) (4th Cir. 2018). Blickenstaff reviewed the pleadings, the discovery responses, and Bowers’s medical records. He reviewed peer-reviewed scientific literature as well as three monographs from the International Agency for Research on Cancer, an agency of the World Health Organization that is the most widely accepted source for classifying agents as causing cancer. “Its monographs are considered authoritative by agencies of the United States. . . .” Lightfoot v. Ga.Pacific Wood Products, 5 F4th 484, 489 (II) (4th Cir. 2021). Those monographs concluded that exposure to diesel exhaust, exposure to asbestos, and exposure to silica all increase the risk of developing lung cancer. Based on the literature, Blickenstaff concluded that even low exposures to diesel exhaust, silica, or asbestos increase the risk of lung cancer, even in smokers. As for the extent of Bowers’s exposure to the toxins, Blickenstaff testified that he reviewed and relied on the report of industrial hygienist Vance. CSX has not challenged Vance’s report. Based on Bowers’s deposition, Vance’s report, and his general knowledge from his own experience in analyzing cases involving railroad workers, Blickenstaff concluded that Bowers had experienced “significant” exposures to diesel exhaust, asbestos, and crystalline silica. Blickenstaff’s written report concludes, Mr. Bowers was diagnosed with lung cancer in 2014 and died from lung cancer in 2018. He did railroad work for 33 years from 1969 to 2002, and was exposed to diesel exhaust, crystalline silica, and asbestos. His heavy smoking no doubt contributed to the causation of his lung cancer, but each of his workrelated exposures also increased the risk in a superadditive or multiplicative manner. Based on my education and experience, and on the documented exposures to diesel exhaust, crystalline silica, and asbestos, it is my opinion, to a reasonable degree of medical certainty, that Mr. Bowers’ railroad work exposures were causally related to his lung cancer. 2. Applicable standards (a) The trial court’s gatekeeping role A trial court’s responsibility to decide whether to admit expert testimony has been described as “a gatekeeping role.” Daubert v. Merrell Dow Pharmaceuticals, 509 U. S. 579, 597 (III) (113 SCt 2786, 125 LE2d 469) (1993). We give broad deference to the trial court to fulfill this role. “Whether expert testimony ought to be admitted under OCGA § 247702 is a question committed to the sound discretion of the trial court. We will not disturb the trial court’s determination absent a manifest abuse of discretion.” Allen v. CFYC Constr., 354 Ga. App. 890, 892 (1) (842 SE2d 297) (2020) (citation and punctuation omitted). But that deference obtains only so long as the trial court acts within the boundaries of that gatekeeping role. As the majority acknowledges , it is not for the courts to weigh the evidence. [I]t is not the role of the trial court to make ultimate conclusions as to the persuasiveness of the proffered evidence. Indeed, a trial court’s gatekeeper role under Daubert is not intended to supplant the adversary system or the role of the jury. Quite the contrary, vigorous crossexamination, presentation of contrary evidence, and careful instruction on the burden of proof are the traditional and appropriate means of attacking shaky but admissible evidence. Emory Univ. v. Willcox, 355 Ga. App. 542, 543-544 (1) (844 SE2d 889) (2020) (punctuation omitted), quoting Quiet Technology DC8 v. HurelDubois UK Ltd., 326 F3d 1333, 1341 (II) (A) (11th Cir. 2003). Accord Lancaster v. BNSF R. Co., 564 FSupp3d 823, 830-831 (D. Neb. 2021), affirmed by 75 F4th 967 (8th Cir. 2023), (“The primary thrust of [the defendant's] argument is that [the challenged expert] failed to ask those people a number of questions that, according to BNSF, were essential to his opinion. The Court is not persuaded that the questions [that expert] did ask were insufficient. Any deficiencies in [the expert's] interview technique go to the weight, not admissibility, of his opinions.”) (emphasis and record citation omitted). We should bear in mind Chief Justice Rehnquist’s warning: “I do not doubt that Rule 702 confides to the judge some gatekeeping responsibility in deciding questions of the admissibility of proffered expert testimony. But I do not think it imposes on them either the obligation or the authority to become amateur scientists in order to perform that role.” Daubert, 509 U. S. at 600–601 (Rehnquist, C. J., concurring in part and dissenting in part). A trial court may not, under color of that gatekeeping role, alter the burden of proof. See United States v. Frazier, 387 F3d 1244, 1272 (IV) (B) (11th Cir. 2004) (court’s exercise of its gatekeeping responsibilities must not “supplant the adversary system”) (citation and punctuation omitted); RuizTroche v. Pepsi Cola of P.R. Bottling Co., 161 F3d 77, 85 (II) (E) (1) (1st Cir. 1998) (“Daubert does not require that a party who proffers expert testimony carry the burden of proving to the judge that the expert’s assessment of the situation is correct. As long as an expert’s scientific testimony rests upon good grounds, based on what is known, it should be tested by the adversary process. . . .”) (citation and punctuation omitted). And our Supreme Court has warned against requiring showings that “may not be possible.” Scapa Dryer Fabrics v. Knight, 299 Ga. 286, 292, n. 9 (788 SE2d 421) (2016). The majority adopts many of CSX’s arguments and holds, on the basis of those arguments, that Blickenstaff’s methodology is unreliable and so that his testimony must be excluded. In doing so, the majority alters the applicable standard, requires showings that are not required under that standard — and that may not be possible, and weighs the evidence. (b) A plaintiff’s burden of proof In a non-FELA toxic tort case, the plaintiff’s burden of proof is to “introduce sufficient evidence to allow a jury to find that more than likely, their exposure to a particular defendant’s product was a factor in producing their injuries.” John Crane, Inc. v. Jones, 278 Ga. 747, 748, n. 1 (604 SE2d 822) (2004) (emphasis added). John Crane called a jury instruction incorporating that language “entirely consistent with established law regarding the concurrent negligence of joint tortfeasors.” Id. at 748, citing Gooch v. Ga. Marble Co., 151 Ga. 462, 463-464 (107 SE 47) (1921). So when a plaintiff alleges that exposure to multiple carcinogens (like the multiple negligent acts of joint tortfeasors addressed in John Crane) caused his injury, the plaintiff must “introduce sufficient evidence to allow a jury to find that more than likely, [his] exposure[s were] a factor in producing [his] injuries.” John Crane, 278 Ga. at 748, n. 1. John Crane was cited with approval in our Supreme Court’s more recent decision, Scapa, 299 Ga. at 290. Scapa clarified the plaintiff’s burden of proof in non-FELA toxic tort cases. John Crane had held that a plaintiff is not required to prove that “each individual tortfeasor’s conduct constitute[s] a ‘substantial’ contributing factor in the injury in order to” prove “proximate cause.” 278 Ga. at 747. Scapa reaffirms that holding and answers the question it left open: what does a plaintiff have to prove? The answer is “a meaningful contribution.” 299 Ga. at 291. Scapa goes on to hold that “a ‘de minimis’ contribution is not enough” under our general tort law. 299 Ga. at 290. But this case falls under the Federal Employers’ Liability Act (FELA), 45 USC § 51 et seq. So the requisite causal contribution is “any part, even the slightest.” Smith v. CSX Transp., 343 Ga. App. 508, 510 (1) (a)
