In rendering its judgment the Court of Appeals apparently disregarded that part of Section 4123.68 (W), Revised Code (formerly Section 1465-68», General Code), which reads:
“Compensation and * * * expenses on account of silicosis are payable * # * only in the event of such disability or death resulting within eight years after the last injurious exposure. In the event of death following con*239tinuous total disability commencing within eight years after the last injurious exposure, the requirement of death within eight years after the last injurious exposure does not apply.”
Furthermore, under State, ex rel. Bessler, v. Indus. Comm. (1952), 157 Ohio St. 297, 105 N. E. 2d 264, the corresponding portion of that statute, as in effect prior to October 12,1945 (having the words “two years” where the words “eight years” now appear), would impose a limitation on the existence of the death claim asserted in the instant case. Unlike in State, ex rel. Venys, v. Indus. Comm. (1950), 153 Ohio St. 238, 91 N. E. 2d 7, the eight-year version of that statute did not become effective until more than two years after decedent’s last injurious exposure to silica dust.
Admittedly, decedent’s last exposure to any silica dust was on January 16, 1943, which was 15 years before decedent’s death in 1958, at the age of 70.
Under the specific provisions of the applicable version of that statute, no compensation for death on account of silicosis could be paid unless decedent’s death occurred prior to January 16, 1945 (last exposure in 1943 plus two years), or unless the decedent was continuously and totally disabled from silicosis from January 16, 1945, until his death. Even if we should overrule our decision in State, ex rel. Bessler, v. Indus. Comm., supra (157 Ohio St. 297), the foregoing quoted portion of Section 4123.68 (W) would prevent such compensation unless the decedent was continuously and totally disabled from January 16, 1951 (last exposure in 1943 plus 8 years), until his death.
In 1945,1947 and 1950, the Industrial Commission disallowed decedent’s claim for compensation on account of total disability from silicosis, and neither the Industrial Commission’s file, nor the judgment entry or opinion of the Court of Appeals indicates that either the Industrial Commission or the Court of Appeals made any subsequent determination as to whether decedent was continuously and totally disabled from 1945, or even from 1951, until his death.
*240The Industrial Commission based its denial of the relator’s death claim on a finding “that proof of record failed to establish that decedent’s death * * * was due to or caused by the disease of silicosis.” If it was not so caused, the death claim was properly denied. Whether it was so caused, was obviously a question of fact.
As the essential basis for its judgment, the Court of Appeals substituted its finding on that question of fact for the finding thereon by the Industrial Commission. In doing so it found that Sction 4123.68(W), Revised Code, “makes the autopsy findings the controlling evidence in regard to the disease of silicosis in a death claim” and disregarded, as does the dissenting opinion, a very substantial amount of evidence tending to indicate that any disability of the decedent prior to death and his death was not caused by silicosis.
The Court of Appeals apparently relied on that part of Section 4123.68 (W) as in force on decedent’s death, which read (this part is not now in the statute, having been eliminated by an amendment effective November 2, 1959 [128 Ohio Laws 743]):
“* * * The commission may designate a licensed physician, a pathologist, or such other specialists as are necessary to make an autopsy examination and tests to determine the cause of death and certify written findings to the silicosis referees.” (Emphasis supplied.)
An autopsy was performed on April 9, 1958, the samé day that decedent died.
The first notice of death and the preliminary application for death benefits were not filed with the Industrial Commission until early October 1958; and the record is clear that the autopsy was not made by anyone designated by the commission and that no written findings were certified to the silicosis referees. Also, the autopsy does not even purport “to determine the cause of death.”
Hence, the foregoing statutory language will not support the conclusion of the Court of Appeals that, under Section 4123.68(W), Revised Code, those “autopsy findings are controlling evidence” in this death claim.
*241By the third paragraph of Section 4123.68(W), “compensation * * * on account of silicosis” is “payable only in the event of * # * death, in accordance with Sections * * * 4123.59.”
Section 4123.59, Revised Code (as in effect on decedent’s death, 126 Ohio Laws 1015,1033), provides for death benefits “in case an injury * * * causes # * * death.”
As pointed out in McNees v. Cincinnati Street Ry. Co. (1949), 152 Ohio St. 269, 275, 89 N. E. 2d 138:
“Although there is no statutory provision requiring a proximate causal relationship between a compensable injury and a death for which compensation is sought, this court has frequently held that it is necessary for a death claimant to establish that such an injury was the proximate cause of the death. Aiken v. Industrial Commission, 143 Ohio St. 113, 53 N. E. 2d 1018; Gwaltney v. General Motors Corp., 137 Ohio St. 354, 30 N. E. 2d 342; Weaver v. Industrial Commission, 125 Ohio St. 465, 181 N. E. 894. * * *”
Since death benefits on account of an occupational disease are provided for by Section 4123.68 (W), Revised Code, via Section 4123.59, Revised Code, which provides for death benefits only where ‘ ‘ an injury * * * causes * * * death,” death benefits on account of silicosis can be awarded only where the death was the proximate result of silicosis proximately caused by exposure to silica dust during employment.
The General Assembly has recognized that, whether disability or death is caused by silicosis, is not within the usual knowledge of lay witnesses or the Industrial Commission, because Section 4123.68 (W), Revised Code, has specifically required medical testimony on that issue.
Thus, at the time of decedent’s death, the sixth paragraph of Section 4123.68(W), provided in part:
“The commission shall appoint three referees to be known as ‘silicosis referees’ who shall be licensed physicians in good professional standing who have by special duty or experience acquired special knowledge of pulmonary diseases and at least one of said physicians shall be a roentgenologist. Before awarding compensation for *242disability or death due to silicosis, the commission shall refer the claim to the silicosis referees for examination and recommendation with regard to the diagnosis, the extent of disability, and other medical questions connected with the claim.”
As amended, effective November 2, 1959, and now in effect without substantial change, that paragraph provides in part:
“Before awarding compensation for disability or death due to silicosis, the commission shall refer the claim to a qualified medical specialist for examination and recommendation with regard to the diagnosis, the extent of disability, the cause of death, and other medical questions connected with the claim.”
What was done and observed at the autopsy is described in the autopsy report largely in medical terms. The diagnosis in the autopsy also consists largely of medical terms.
The final diagnosis in the autopsy includes seven items. Only the second of the seven even indicates silicosis.
An understanding of these medical terms requires a special knowledge thereof that would ordinarily be far beyond the comprehension of laymen. For this reason, that autopsy report would be useful to the trier of the facts in the instant case (the Industrial Commission) only if interpreted by medical experts. In other words, the autopsy report, without such interpretation, can have little probative value on the question of whether there was a proximate causal connection between decedent’s death and his exposure to silica dust during his employment over 15 years before. Cf. Stacey v. Carnegie Illinois Steel Corp. (1951), 156 Ohio St. 205, 101 N. E. 2d 897; Fox v. Indus. Comm. (1955), 162 Ohio St. 569, 576, 577, 125 N. E. 2d 1; Drakulich v. Indus. Comm. (1940), 137 Ohio St. 82, 27 N. E. 2d 932.
There is such testimony in the file. That of Dr. Steiner, whose bill for services indicates that he had attended decedent from 1949 until prior to decedent’s hospitalization two years before his death, would support a conclusion *243that decedent’s death was proximately caused by silicosis. So would the death certificate, which was prepared by this doctor.
However, while decedent was in the hospital where the autopsy was conducted his attending physician was Dr. Maurer. The hospital chart signed by him states his opinion as to the cause of death. Nowhere therein is there any reference to silicosis.
Also, the file contains a statement by Dr. Hudson, who was apparently asked to and did review the file, including (contrary to the statement in the dissenting opinion) the autopsy report, the death certificate and the testimony of Dr. Steiner. Thereafter, he gave to the Industrial Commission a written statement of his opinion. This statement reads:
“From a study of the claim, medical proof and reports on file, the deceased’s death was due to hypertensive cardiovascular disease, myocarditis and mitro stenosis. Claimant had an unrelated emphysema and bronchitis that was not due to or aggravated by silicosis, and we do not concur in the cause of death ‘silicosis’ as reported on the death certificate.
“The claimant was not exposed to silica after he quit work and there would not be any increase in the silicosis or silicotic nodulation. The claimant’s pulmonary condition was due to the emphysema and bronchitis and we do not concur in the opinion and conclusions of the attending physician.
“Medically disapproved.”
The Industrial Commission file discloses further that decedent had been thoroughly examined by the silicosis referees and X-rays had been taken in 1943, 1945, 1947 and 1949. In each instance, the silicosis referees concluded that there was no disability of decedent due to silicosis.
On the record in the instant case, it is obvious that there is substantial evidence to support the conclusion of the Industrial Commission that decedent’s death was not caused by silicosis, not merely what the dissenting opinion *244refers to as “slight evidence.” Thus, the Court of Appeals erred in substituting its contrary finding on that question of fact for the finding of the Industrial Commission.
As stated in the syllabus in State, ex rel. Bevis, v. Coffinberry (1949), 151 Ohio St. 293, 85 N. E. 2d 519:
“1. Before a writ of mandamus will be granted a clear legal right thereto must be shown, and the burden of establishing such right is upon the relator.
ÉC# # #
“3. Whether disability suffered by a claimant is silicosis and whether the resulting disability is partial or total are questions of fact to be determined by the Industrial Commission, from which decision no appeal has been provided by law.”
The following statement in the opinion by Matthias, J., at page 296, is particularly applicable to the instant case:
“The question presented to this court by the facts alleged in the petition involves the determination of a purely medical question of fact. The determination of such a question as the relator presents here, that is whether the complicating diseases of pulmonary emphysema and asthmatic bronchitis were caused by the silicosis condition, is so clearly a question of fact that the granting of a writ by this court would be in effect a requirement that the Industrial Commission determine a question of fact in the manner in which this court believes it should have been found and determined. It is clear that there was a positive difference of opinion between the medical authorities constituting the silicosis referees and the medical board of review of the Industrial Commission on the one hand, and the physicians who examined the relator on the other. In such a situation the relator obviously does not show a clear right to relief by way of mandamus and under the well established rule such a writ will not issue.”
To the same effect, see State, ex rel. Marshall, v. Keller, ante 203.
Also, in the per curiam opinion of this court in State, ex rel. Brewer, v. Indus. Comm. (1950), 153 Ohio St. 471, *24592 N. E. 2d 385, it is said, with reference to an attempt to get a court to substitute its judgment on a question of fact for that of the Industrial Commission:
“We do not pass upon the weight of evidence, being limited to ascertaining whether there was evidence pertaining to the point challenged.”
For the foregoing reasons, the judgment of the Court of Appeals is reversed and final judgment is rendered for the Industrial Commission.
Judgment reversed.
Zimmerman, Matthias and O’Neill, JJ., concur. Brown, J., concurs in paragraphs one, three and four of the syllabus and in the judgment. Herbert and Schneider, JJ., dissent.