dissenting.
As the majority acknowledges, this court’s standard of review of the hearing officer’s decision is identical with the standard which controls the Benefits Review Board: the decision must be supported by substantial evidence, not irrational, and in accordance with law. The record convinces me that the hearing officer’s decision lacks support of substantial evidence. Even the Benefits Review Board demurred when applying the substantiality test. Rather than making an affirmative finding, it stated ambiguously, “The Board cannot say that the hearing officer’s conclusion that the claimant is totally disabled by pneumoconi-osis is not supported by substantial evidence, is irrational or is not in accordance with law.” (Emphasis added.) Unfortunately, the majority seems to have no difficulty determining in positive terms that the decision meets the test. Nonetheless, even if substantial evidence could be said to exist, the decision would, in my opinion, be irrational and not in accordance with law.
Black lung benefits may be awarded only when the “primary” cause of a claimant’s total disability is pneumoconiosis, a chronic dust disease arising out of employment in a coal mine. 30 U.S.C. § 902, 20 C.F.R. § 410.426(a).1 In the case at bar the evidence establishes that the actual cause of the claimant’s inability to continue his employment was coronary artery disease. He worked continuously until he had a coronary attack in August 1973. He quit work on September 1, 1973, and had open heart surgery three weeks later. At the hearing on his claim, he testified that he was forced to quit work because of his heart condition,2 and that his doctor told him after the operation that his working days were over.
Upon admission to the Indiana University Hospital on September 12, 1973, the claimant gave a medical history wherein he denied dyspnea, orthopnea, nocturnal dyspnea, syncope, or any other pulmonary problems.3 He told the examining physician, Dr. Walter E. Judson, that he was in very good general health until May 1973 when he first experienced chest pains which led to the diagnosis of cardiac disease and which had been relieved by nitroglycerin. Chest X-rays before and after the heart surgery showed “the lung fields were clear.” At a subsequent examination on March 13, 1975, by Dr. Martin W. Davis, an internist, the chest X-rays showed “no definite evidence of nodulation or consolidation such as seen in pneumoconiosis.” Dr. Davis’ report also stated: “his pulmonary function studies are abnormal but this is probably due to his cardiovascular disease. Actually, his pulmonary function is adequate to perform a job requiring moderate physical exertion.” He ended his report by stating:
It is my opinion that Mr. Charles Wells is not disabled from a pulmonary standpoint. I do not believe that he has any definite evidence of pneumoconiosis. I believe that he is permanently, partially disabled as a result of cardiovascular disease, not related to his occupation.
*804Opposed to this strong evidence is an interpretation by Dr. R. H. Browning of an X-ray examination made in January 1974. Dr. Browning found a number of small opacities in claimant’s lungs which were classified “Category 1” in the medical classification of pneumoconiosis. The opacities were “some small rounded opacities of the smallest size (type p), and the lowest profusion level (1/1), under the Internal Classification system (UICC).” Further there was admitted into evidence a pulmonary function study taken while claimant was recuperating from his heart surgery which showed values below the table of values in 20 C.F.R. § 410.426. This was the extent of the medical evidence on which the hearing officer found that the claimant was afflicted with pneumoconiosis. The hearing officer also referred to claimant’s own description of his condition and of his “ample exposure to coal dust.”
After first concluding that claimant’s heart condition was a cause of his total disability, the hearing officer determined claimant’s lung condition also resulted in his total disability to engage in any gainful work. The hearing officer reasoned:
The record evidence amply demonstrates that Claimant is unable to engage in gainful work comparable to that involved in his previous vocation as a result of a totally disabling heart condition. However, this determination does not answer the critical question before me, namely, whether or not he is totally disabled by reason of his pneumoconiosis. For the reasons stated below, I conclude that Claimant is so disabled.
The pulmonary function studies performed at Doctors Hospital, and those performed by Dr. Davis, meet the regulatory standards (20 CFR 410.426) for establishment of respiratory disability. The results of these studies are consistent with Claimant’s credited testimony concerning his shortness of breath and the physical limitations caused by that condition. While Dr. Davis stated in his report that Claimant’s abnormal pulmonary function studies are “probably due to his cardiovascular disease” (emphasis added), this qualified diagnosis is also based, at least in part, on the doctor’s observation that Wells’ work history does not suggest adequate exposure to dust to cause a pneumoconiosis. As I have earlier rejected this premise, and conclusions based upon it, I believe that the ventilatory studies should be accepted at their face value and interpreted in accordance with the regulatory standards. As so interpreted, these studies establish that Claimant is totally disabled by reason of a respiratory disease.
I conclude, on the basis of the pulmonary function studies and Claimant’s own description of his condition, that Claimant’s respiratory disablement prevents him from engaging in any gainful work even remotely comparable to that involved in his previous vocation. In view of Claimant’s pneumoconiosis, and the evidence establishing a totally disabling respiratory impairment, the inference is warranted that pneumoconiosis is the operative cause, in whole or in part, of Claimant’s totally disabling respiratory condition.
A study of the foregoing analysis suggests that the hearing officer was “swimming upstream” in reaching his ultimate findings. Moreover, the hearing officer’s reasoning has a tendentious quality that prevents his decision from fully meeting the rationality test. Equally important, the hearing officer failed to meet the regulatory requirement that before benefits may be awarded, a claimant’s pneumoconiosis must be found to be the primary reason for his total disability.
In an effort to excuse this failure, the majority of the Benefits Review Board said that the hearing officer’s finding that the claimant’s pneumoconiosis “is sufficiently severe as to be totally disabling,” meets the regulatory requirement. In the face of the heart ailment, which the hearing officer found initially as totally disabling, the Board’s statement simply fails to come to grips with the issue.
*805The majority of this court in an attempt to meet the obstacle head-on, struggles to demonstrate that the hearing officer’s term “in whole or in part” is somehow equivalent to saying that his lung condition is the “primary cause” of his total incapacity to work. “Primary” means to me either first in time or first in degree. I am unable to see how the examiner’s statement that “the inference is warranted that pneumoconiosis is the operative cause in whole or in part of claimant’s total respiratory condition” is the same as saying that claimant’s lung condition is “the primary reason” for his inability to engage in gainful work. (Emphasis added.) Rather, the language used by the hearing officer further demonstrates that his decision is both irrational and not in accordance with law.
I am in agreement with the dissent of the chairman of the Benefits Review Board:
The medical evidence does not support a finding that the claimant has a totally disabling respiratory condition, let alone that pneumoconiosis is the primary reason for his inability to engage in comparable and gainful work.
Claimant worked at his usual coal mine employment up until the time he had to have treatment, including surgery, for severe cardiovascular disease. The record is clear, and all parties agree, that the claimant is totally disabled by heart disease.
The record in this case does not establish that the claimant is totally disabled by pneumoconiosis according to the applicable regulatory standards pursuant to Sections 411(a), (b) and 422(h) of the Act.
In sum, the Benefits Review Board failed to follow proper standards of review of the hearing officer’s decision, which, in my judgment, rests on suppositions and unwarranted inferences. I would reverse.
. 20 C.F.R. § 410.426(a) provides in part:
[A] miner shall be determined to be under a disability only if his pneumoconiosis is (or was) the primary reason for his inability to engage in . comparable and gainful work.
. An excerpt from the claimant’s testimony reads:
Q. Did you retire at that time?
A. I was forced to quit work.
Q. Why did you quit work?
A. From physical examination.
Q. What was the nature of the physical examination?
A. Heart trouble.
. The words are defined as follows:
Dyspnea — shortness of breath — difficult or labored expiration,
Orthopnea — inability to breathe except in an upright position, and
Syncope — a partial or complete temporary suspension of respiration or circulation.