dissenting.
{¶ 34} I believe that the trial court abused its discretion when it excluded the opinions of plaintiffs expert witnesses. The opinions were sufficiently reliable to establish a genuine issue of material fact on causation in order for the issue to withstand summary judgment. Therefore, I respectfully dissent.
{¶ 35} The decedent worked with and was exposed to a number of chemicals in the workplace, including toxic agents and carcinogens, on a daily basis for 30 years. He succumbed to an extremely rare form of brain cancer, glioblastoma multiforme, at age 52. He did not smoke or abuse alcohol and had no family history of brain cancer. He was in excellent health until his diagnosis. Within seven days of Valentine’s death, a laboratory co-worker, Hal McConnaughey, who had been exposed to the same chemicals, also died of the same rare brain tumor, at age 49. These two deaths are significant in that glioblastoma multiforme occurs in approximately 1.5 of every 10,000 males in the United States.
{¶ 36} Three expert witnesses offered opinions that the decedent’s disease was directly and proximately caused by his long-term exposure to toxic chemicals in the workplace. Two of the witnesses were his treating physicians; the third was an industrial hygienist who had evaluated his work environment. It is not disputed that these experts are eminently qualified professionals and that their opinions related to “matters beyond the knowledge” of laypersons. Evid.R. 702(A). The trial court, however, concluded that the opinions were not based on reliable scientific information.
{¶ 37} These experts used their professional knowledge to synthesize and extrapolate information from various sources to connect the decedent’s exposure to toxic chemicals in the workplace with his brain tumor. I believe that these opinions reached the threshold level of admissibility of evidence under Evid.R. 702 and that it was arbitrary and unreasonable for a judge to summarily dismiss their conclusions as unreliable.
Norman Brusk
{¶ 38} Norman Brusk, a certified industrial hygienist with more than 30 years’ experience in this field, evaluated the decedent’s work environment and concluded that he had “unquantifiable, but significant exposures to cancer causing and potentially cancer causing chemicals via airborne, skin absorption and ingestion routes of exposure.” During the earlier years, in the 1960s and 1970s, the decedent did not wear any protective clothing or use protective equipment while working, so his exposure to carcinogens would have been even greater then than in later years.
*50{¶ 39} Brusk also cited a number of studies in which clusters of workers who had been exposed to toxic chemicals were diagnosed with brain cancer. At a petrochemical research facility, “patterns suggest that the brain cancer excess resulted from occupational exposures.” A study comparing chemists with architects “supports the suggestions that chemical exposure is a cause of both leukemic and hematopoetic tumors and brain tumors and thus indicates the occupational hazards in chemical work.” Another study of petrochemical workers indicated an excessive number of brain tumors and that they are likely to be occupation-related. A study of women in China concluded that persons in occupations in which they were exposed to organic solvents had a significantly elevated risk for brain cancer.
{¶ 40} Brusk concluded, “Based on my assessment of Mr. Valentine’s workplace, the above studies, my experience as an industrial hygienist as well as a chemist, and the occurrence of clusters of brain cancers in chemical related fields, it is my professional opinion that Mr. Valentine had a higher risk of developing brain cancer because of his position as a laboratory technician than of employees in the general workforce and of the population as a whole.”
Dr. Michael Miner
{¶ 41} Dr. Michael Miner has practiced neurosurgery for more than 25 years. He is a professor of neurological surgery and Director of the Division of Neurosurgery at the Ohio State Medical School. He has “worked extensively with patients with glioblastoma multiforme” and has performed “extensive research on people with brain tumors both clinically and in the laboratory.”
{¶ 42} Dr. Miner relied on his 25 years of neurosurgical practice, his research, medical literature on genetics, animal studies, and human epidemiological studies to conclude that the decedent’s brain tumor was directly and proximately caused by extensive exposure to a combination of chemical toxins in the workplace. In support of his opinion, Dr. Miner cited genetic research that documented the impact of the carcinogen benzene on the P53 suppressor gene in animals. Animals exposed to benzene developed the type of brain tumor that the decedent developed. The decedent had been exposed to benzene, a substance no longer commonly used in laboratories because of its potential danger.
{¶ 43} Dr. Miner also pointed to laboratory studies that documented brain tumors in rats that had been exposed to acrylonitrile and ethylene oxide. These are substances to which the decedent was exposed and that are known to either cause or have the potential to cause changes in human cells that result in cancer.
{¶ 44} Dr. Miner relied upon epidemiological studies that documented a higher than expected incidence of brain tumors in people exposed to carcinogens like those to which the decedent had been exposed. The studies indicated an *51increased risk of cancer, including brain cancer, in laboratory technicians and chemists who had routinely handled solvents. Dr. Miner cited studies of persons who had worked in the petroleum industry. Those studies also documented an increased risk of brain tumors from exposure to solvents, especially benzene.
{¶ 45} Dr. Miner explained that the decedent and McConnaughey worked with the same carcinogens for a number of years in the same environment, and both developed an extremely rare form of brain cancer. There were few, if any, other people at PPG Industries, Inc., who had worked in the same environment for a similar number of years. Epidemiological studies usually involve a large group of people and would not reveal the significance of these tumors, because the two men would have been subsumed in a large group of employees who did not work in the identical environment. Dr. Miner explained that epidemiological studies are not designed to examine small groups. Furthermore, recreating the exact chemical exposure that these men sustained over such a long period would be impossible.
{¶ 46} Dr. Miner concluded that “cumulative evidence in medical literature and experience does provide substantial basis to state that long term excessive exposure to the solvents and other cancer causing chemicals identified in Mr. Valentine’s specific working environment can cause brain cancer (glioblastoma multiforme).”
Dr. Herbert Newton
{¶ 47} Dr. Herbert Newton is Director of the Division of Neuro-Oncology at the Ohio State University Medical Center and the James Cancer Hospital. He is also an associate professor of neurology and pediatrics in the Department of Neurology at Ohio State. During his tenure at the James Cancer Hospital, Dr. Newton has diagnosed and cared for more than 1,000 patients with brain tumors, over half of them with glioblastoma multiforme.
{¶ 48} Dr. Newton also opined that, based on a reasonable medical probability, the decedent’s brain tumor was directly and proximately related to his exposure to numerous potentially neurocarcinogenic chemicals over many years. He noted that the decedent’s type of brain tumor is rare; it is responsible for approximately seven of every 100,000 deaths per year in the United States. Furthermore, it takes decades for a brain tumor to develop. Dr. Newton concluded that these facts are consistent with the decedent’s history of chronic toxic exposure for over 30 years at PPG Industries. Dr. Newton also noted the death of McConnaughey, the decedent’s co-worker.
{¶ 49} Dr. Newton’s opinion relied on epidemiological evaluations of “clusters” of persons in the petroleum and chemical industries who developed brain tumors. In one cluster, 19 persons from the same plant with long-term exposure to many *52solvents were diagnosed with brain tumors. Another cluster consisted of six chemists from the same building who developed gliomas. The study concluded that the employees at the complex had a risk of developing a brain tumor eight times that of the general population.
{¶ 50} Dr. Newton acknowledged the limitations of human epidemiological research in the study of brain tumors. Brain tumors are uncommon in the general population. It is difficult to define a group to evaluate in terms of amount and duration of toxic exposure. And it would be difficult and inherently inaccurate to reconstruct employees’ chemical exposures in the workplace for purposes of a study.
{¶ 51} Ohio favors the admission of expert evidence so long as it is relevant and reliable and will assist the trier of fact. State v. Nemeth (1998), 82 Ohio St.3d 202, 211, 694 N.E.2d 1332. Evid.R. 702. Evidence should not be excluded merely because it is questionable or confusing. Miller v. Bike Athletic Co. (1998), 80 Ohio St.3d 607, 614, 687 N.E.2d 735. These experts’ opinions would be subject to cross-examination, and the credibility of the conclusions should be matters for the trier of fact. Nemeth, 82 Ohio St.3d at 211, 694 N.E.2d 1332.
{¶ 52} I agree that, to be admissible, an expert’s opinion must be based on valid, reliable information in light of the multitude of professional experts in our litigious society known as “hired guns.” And with advances in science and technology, courts must ensure that the underlying basis of expert testimony meets the legal standard for admissibility of evidence under Evid.R. 702. However, in our zealousness to curb abuse, we cannot permit a court to unreasonably and arbitrarily exclude expert evidence.
{¶ 53} In Wilson v. CSX Transp., Inc. (Tenn.App.2003), No. E 2002-00291-COA-R9-CV, 2003 WL 1233536, a Tennessee court of appeals ruled that the testimony of three expert witnesses was admissible to establish a genuine issue of material fact regarding the cause of the death of Ricky J. Wilson, a carman for CSX. Wilson was diagnosed at age 40 with the same type of brain tumor as Valentine’s, a glioblastoma multiforme, and leukemia. He died two years later.
{¶ 54} Wilson’s widow alleged that his exposure to various toxic chemicals at work, such as benzene and other carcinogens, caused or contributed to cause his brain cancer and leukemia. She presented testimony of a chemist, a pathologist-toxicologist, and a physician. The trial court had permitted the testimony of the chemist and the pathologist-toxicologist, but had excluded the testimony of the physician, claiming that his testimony lacked studies or statistical data to back up the opinion.
{¶ 55} Applying the Tennessee standard of admissibility of expert evidence, that a court “must assure itself that the opinions are based on relevant scientific methods, processes, and data, and not upon an expert’s mere speculation,” the *53court concluded that the opinion was based on valid and relevant science, not speculation. Id. at *5. The CSX experts offered opinions in opposition to the plaintiffs experts; however, the appellate court explained that the weight and credibility of the competing scientific views are matters appropriately left to the trier of fact. Id. See, also, Hand v. Norfolk S. Ry. Co. (Tenn.App.1998), No. 03A01-9704-CV-00123, 1998 WL 281946, *4, in which the court allowed expert testimony that Hand’s exposure to certain solvents, including benzene and other carcinogens, during his 25 years with the railroad caused or contributed to the glioblastoma multiforme, of which he died at age 58.
Larrimer & Larrimer and Terrence W. Larrimer; Young, Tootle & Dumm and Gary Dumm, for appellant. Thompson Hiñe, L.L.P., Timothy J. Coughlin, and Karen E. Rubin; Habash, Reasoner & Frazier, L.L.P., and Stephen J. Habash; Shoemaker, Howarth & Taylor and Kevin Shoemaker, for appellees. Jim Petro, Attorney General, Douglas R. Cole, State Solicitor, Elise W. Porter, and René L. Rimelspach, Assistant Solicitors, for amicus curiae Ohio Attorney General. Stewart Jaffy & Associates Co., L.P.A., Stewart R. Jaffy, and Marc J. Jaffy, urging reversal for amicus curiae Ohio AFL-CIO. Paul W. Flowers Co., L.P.A., and Paul W. Flowers; Philip J. Fulton Law Office and Philip J. Fulton, urging reversal for amicus curiae Ohio Academy of Trial Lawyers. Squire, Sanders & Dempsey, L.L.P., William M. Todd, and Greta M. Kearns, urging affirmance for amici curiae Ohio Chamber of Commerce, Ohio Manufacturers Association, National Federation of Independent Business/Ohio, and Ohio Chemistry Technology Council.*53{¶ 56} Like Judge Abele in the court below, I, too, am troubled by the application of the law to the facts of this case. Three highly qualified expert witnesses proffered opinions based upon information, experience, and science that cumulatively supported their conclusions. Two of the experts were the decedent’s treating physicians, who are associated with outstanding medical institutions, the Ohio State University School of Medicine and the James Cancer Hospital. The third expert, Norman Brusk, has more than 30 years’ experience in industrial hygiene. These witnesses were not “hired guns.” They did not use unscientific principles and methodology. These opinions are not “junk science.”
{¶ 57} I believe that the opinions of experts Miner, Newton, and Brusk were sufficiently reliable for admission and that the trial court abused its discretion when it excluded their testimony. Therefore, I respectfully dissent and would reverse the judgment of the court of appeals and remand for further proceedings.
Resnick and Pfeifer, JJ., concur in the foregoing opinion.