Rutledge v. Tultex Corp./Kings Yarn

Justice MEYER

dissenting.

I respectfully dissent. The majority today, although without expressly so stating, has subtly but effectively reversed the position of this Court, adopted so recently in Morrison v. Burlington Industries, 304 N.C. 1 , 282 S.E. 2d 458 (1981), Hansel v. Sherman Textiles, 304 N.C. 44 , 283 S.E. 2d 101 (1981), and Walston v. Burlington Industries, 304 N.C. 670 , 285 S.E. 2d 822 (1982). In these three cases the Court was confronted, as it is in the present case, with difficult and complex issues relating to causation, apportionment, and disability. I believe that a careful reading of the majority opinions in Morrison, Hansel and Walston will reveal a correct, logical and consistent approach to these issues and that adherence to the principles enunciated in these cases leads to the inescapable conclusion that this claimant has failed to prove that she is entitled to compensation.

The majority would have us believe that the “difference between the majority and the dissenters in Morrison rested largely on how the evidence in that case should have been interpreted and whether the Commission’s findings were supported by the evidence.” In fact, the difference was far more significant and fundamental. It is that difference, as expressed in the Morrison dissent, which today forms the basis for the majority’s opinion.

In Morrison the dissenters first found as a “fundamental legal” error the majority’s position that “unless an occupational disease medically aggravates or accelerates some pre-existing condition, it must be the sole cause of a worker’s incapacity for work in order for the worker to be compensated for the full extent of the incapacity.” Id. at 23 , 282 S.E. 2d at 473 . In this respect, the dissenters wrote:

Neither must the worker in such cases, contrary to the majority’s assertion, show that the occupational disease is medically related to his pre-existing infirmities or that these infirmities have somehow been medically aggravated by the disease. The question is not how the occupational disease and *110 the other infirmities are medically connected. The question is how they are connected vis-a-vis the worker’s capacity to work. This is the true meaning of the aggravation principle, recognized but wrongly restricted by the majority to aggravation in a medical sense.

Id. at 24-25 , 282 S.E. 2d at 473-74 .

The dissenters further commented that:

Neither is it necessary that the industrial accident or occupational disease be medically related to, or medically aggravate, the worker’s pre-existing infirmities. It is enough if the industrial accident or occupational disease physically combines or interacts with the worker’s pre-existing infirmities to produce incapacity for work so long as these pre-existing infirmities are themselves insufficient to cause any incapacity for work. In such cases the award may not be made as if the worker were incapacitated only to the extent of the industrial accident’s or occupational disease’s contribution.

Id. at 37 , 282 S.E. 2d at 481 .

The second fundamental legal error committed by the majority, as alleged by the Morrison dissenters, was its position “that occupational conditions must be the sole cause of an occupational disease in order for a worker to be compensated for the full extent of the incapacity for work caused by the disease.” Id. at 23 , 282 S.E. 2d at 473 .

Speaking to this question, the dissenters would have adopted the “significant contribution” test as follows:

The notion of ‘reasonable’ or ‘substantial’ contribution referred to in these cases is better expressed by the term ‘significant.’ The occupational conditions, in other words, must have significantly contributed to the disease’s development in order for the disease to be occupational. Significant means ‘having or likely to have influence or effect: deserving to be considered: Important, Weighty, Notable.’ Webster’s Third New International Dictionary (Merriam-Webster 1971). Significant is to be contrasted with negligible, unimportant, present but not worthy of note, miniscule, of little moment. The factual inquiry, in other words, should be *111 whether the occupational exposure was such a significant factor in the disease’s development that without it the disease would either (1) not have developed or (2) not have developed to such an extent as to result in the employee’s incapacity for work for which he claims benefits.

Id. at 43 , 282 S.E. 2d at 484 .

The issue in the present case, as framed by the majority, is “whether a textile worker’s chronic obstructive lung disease may be an occupational disease under G.S. 97-53(13) when it is caused in part by the worker’s on-the-job exposure to cotton dust and in part by exposure to other substances, such as cigarette smoke, and when the disease has other components like bronchitis and emphysema which in their incipience at least are not work related.” It seems clear to me that the majority today has adopted the dissenting opinion in Morrison in its holding that “chronic obstructive lung disease may be an occupational disease provided the occupation in question exposed the worker to a greater risk of contracting this disease than members of the public generally, and provided the worker’s exposure to cotton dust significantly contributed to, or was a significant causal factor in, the disease’s development. This is so even if other non-work-related factors also make significant contributions, or were significant causal factors. ” (Emphasis added.)

In adopting the dissenters’ position in Morrison , the majority in the case sub judice must now understandably find that the “Industrial Commission decided this case under a misapprehension of applicable law . . . .” The majority attempts to distinguish this case from Morrison, Hansel and Walston in that Mrs. Rutledge suffers from chronic obstructive lung disease rather than byssinosis. The majority attempts to distinguish this case on the basis of slight factual variations. These attempted distinctions, in my opinion, do not disguise the fact that the “applicable law” has undergone a drastic and significant change. In effect, the majority has redefined “occupational disease” to include all ordinary diseases of life to which conditions of the workplace have significantly contributed, irrespective of non-work-related causal factors. The proposition has no statutory basis. We should leave the adoption of new laws to the Legislature, especially when the new law replaces old law which is exclusively statutory in origin.

*112 To fully appreciate just how significantly the majority opinion departs from our existing law, it is necessary to review at least the highlights of the testimony of the only expert medical witness who testified, Dr. Charles D. Williams, Jr., a specialist in pulmonary disease and a member of the Industrial Commission’s Occupational Disease Panel. The following represents a fair summary of his testimony:

I had occasion to examine and evaluate Margaret Rutledge in this particular case. That was in August of 1979. At that time I took a history from Mrs. Rutledge and I did pulmonary function testing and we did complete blood counts, urinalysis, chest X-ray, chemistry profile, electrocardiogram. I also examined Mrs. Rutledge.

.... To describe the particular kinds of pulmonary conditions that I am familiar with that exist with some frequency in textile workers, byssinosis is the primary disease associated with textile workers. Byssinosis is a disease which in its acute phase is characterized by symptoms of chest tightness, wheezing, shortness of breath and cough, which typically occur on the first day of the week after returning from the weekend, and initially improve as the work week goes on. Later it is possible to progress into a chronic phase which is indistinguishable from other chronic obstructive pulmonary disease. Based upon my experience and familiarity with the literature I can state whether or not textile workers are at an increased risk of contracting chronic obstructive pulmonary disease. That opinion is that they are. That opinion is irrespective of whether or not the textile worker can relate symptoms of the Monday morning or startup day symptoms I mentioned, since apparently, it is possible to develop chronic obstructive pulmonary disease without having the classical acute phase symptoms. There are other named conditions that would fit within that general category. Chronic obstructive pulmonary disease includes pulmonary emphysema, chronic bronchitis, and possibly asthma.

As a result of my objective findings, that is my physical examination and pulmonary function tests and other studies that I had performed, I formulated an opinion regarding Mrs. *113 Rutledge’s capability of physical labor. That opinion was that I felt that she should not work around irritating dust, fumes or smoke, and that she should not be expected to do any type of work requiring significant physical exertion. I felt that she would be able to do sedentary type work in a clean environment assuming that she had the necessary training and other capabilities and that such work were available.

As to my diagnosis of Mrs. Rutledge’s condition at the time of my examination, it was my feeling that she had pulmonary emphysema, chronic bronchitis, possibly arteriosclerotic heart disease with angina pectoris and congestive heart failure which was then compensated, migraine, urinary incontinence of undetermined etiology, arthralgia of her back and fingers of undetermined etiology, and hypertriglyceredema. I would not expect Mrs. Rutledge’s obstructive pulmonary disease to improve significantly; she would probably show progressive impairment with time although this would be influenced in some measure by her therapy.

Q: . . . . Now, based upon these facts and upon your examination and testing of Ms. Rutledge, do you have an opinion satisfactory to yourself to a reasonable medical certainty as to whether Ms. Rutledge’s exposure to cotton dust for in excess of 25 years in her employment was probably a cause of her chronic obstructive lung disease which you diagnosed in your report?

A: Yes.

Q: What is that opinion?

A: Yes. That it probably was a cause.

Based upon the same facts and upon my examination and testing of Mrs. Rutledge, I have an opinion as to whether her impairment with respect to her ability to perform labor is related to her pulmonary disease. That opinion is that it is.

When I was examining Mrs. Rutledge I got a history from her. This history included her history as to smoking. *114 She gave me the history that she began smoking at age 15 and averaged one pack of cigarettes daily until she stopped smoking in February, 1979. I think cigarette smoking is a very important, often the primary cause, of chronic obstructive pulmonary disease. Based upon the facts that Ms. Hudson has given me and based upon by examination and particularly upon the history of cigarette smoking that Mrs. Rutledge gave me it is my opinion satisfactory to myself to a reasonable degree of medical certainty is that her history of cigarette smoking could or might have been the cause of her pulmonary emphysema and chronic bronchitis. Based upon my examination and these facts, I would say it was one of the more probable causes. This is after taking into consideration her exposure to cotton dust.

... In other words at the time of her employment on that date [October 25, 1976] she was suffering from pulmonary emphysema, chronic bronchitis and chronic obstructive pulmonary disease.

Q: Do you have an opinion satisfactory to yourself and to a reasonable degree of medical certainty as to what effect, if any . . . [the] exposure ... [at defendant’s mill] to Ms. Rutledge would have had to her?

Ms. HUDSON: Objection to the form.

A: Yes.

Q: What is that opinion?

A: I think it would be minimal.

Based upon the history of exposure that she gave me of her employment at Kings Yarn, in my opinion the exposure during that two-year period would not be a very substantial exposure; assuming this was in the spinning department and that she was using a synthetic and cotton blend being processed, not having actual dust measurements available. In my opinion her condition of pulmonary emphysema and chronic bronchitis was not caused by this exposure in this period of *115 23 months. I do have an opinion satisfactory to myself and to a reasonable degree of medical certainty as to whether or not this exposure had any affect upon her condition. I think that exposure to any type of dust in someone with pre-existing chronic bronchitis could have some aggravating effect on the underlying condition.

Assuming that Mrs. Rutledge was capable of doing her job in October of 1976 at Kings Yarn, and she was exposed to respirable dust of cotton and synthetic yarns at her job at Kings Yarn, and she was unable to do her job at the time she left, I would not have an opinion as to whether her exposure at Kings Yarn aggravated her condition. I feel that whether a person is capable of performing a job or not is quite a subjective matter that is influenced by many factors of physical, emotional and sociological. I would not have an opinion.

I stated that exposure to any kind of dust in an individual with underlying lung disease would have an aggravating effect. It would also be my opinion that in Mrs. Rutledge’s individual case, her exposure to respirable cotton and synthetic dust at Kings Yarn would have aggravated her condition.

Our statute relating to occupational diseases is very specific and does not support the majority’s conclusion. I need only repeat what this Court said in Hansel v. Sherman Textiles, 304 N.C. 44, 51-52 , 283 S.E. 2d 101, 105 .

G.S. 97-52 provides in effect that disablement of an employee resulting from an ‘occupational disease’ described in G.S. 97-53 shall be treated as the happening of an injury by accident. This section provides specifically:

The word ‘accident’ . . . shall not be construed to mean a series of events in employment of a similar or like nature occurring regularly, continuously . . . whether such events may or may not be attributable to the fault of the employer and disease attributable to such causes shall be compensable only if culminating in an occupational disease mentioned in and compensable under this article. (Emphasis added.)

*116 G.S. 97-53 contains the comprehensive list of occupational diseases for which compensation is provided in the Act.

By the express language of G.S. 97-53, only the diseases and conditions enumerated therein shall be deemed to be occupational diseases within the meaning of the Act.

Byssinosis is not ‘mentioned in and compensable under’ the Act, except by virtue of G.S. 97-53, which provides in pertinent part as follows:

Section 97-53. Occupational diseases enumerated; . . . the following diseases and conditions only shall be deemed to be occupational diseases within the meaning of this Article:

(13) Any disease . . . which is proven to be due to causes and conditions which are characteristic of and peculiar to a particular trade, occupation or employment, but excluding all ordinary diseases of life to which the general public is equally exposed outside of the employment.

My interpretation of our Act is detailed in Morrison v. Burlington Industries, 304 N.C. 1 , 282 S.E. 2d 458 . It suffices here to say only that any disease, in order to be compensable, must be an occupational disease, or must be aggravated or accelerated by an occupational disease or by an injury by accident arising out of and in the course of the employment. G.S. § 97-53(13); Booker v. Medical Center, 297 N.C. 458 , 256 S.E. 2d 189 (1979); Anderson v. Motor Co., 233 N.C. 372 , 64 S.E. 2d 265 (1951). Today the majority severs this causation link and, in its place, inserts the new principle of “significant contribution.” We also said in Hansel- “The clear language of G.S. 97-53 is that for any disease, other than those specifically named, to be deemed an ‘occupational disease’ within the meaning of the Article, it must be ‘proven to be due to,’ causes and conditions as specified in that statute.” Hansel v. Sherman Textiles, 304 N.C. at 52, 283 S.E. 2d at 105 . I fail to see how the “significant contribution” principle originated in the majority opinion can satisfy the “proven to be due to” requirement of the statute.

Thus far the opinions of this Court have, for the most part, been faithful to the intent of the Legislature when it enacted the *117 occupational disease provisions of the statute, i.e. — that compensation is to be paid only for disabilities unmistakably caused by exposure to causes and conditions peculiar to the workplace rather than for disabilities more likely than not to have been caused by exposure to such causes and conditions. See Walston v. Burlington Industries, 304 N.C. 670 , 285 S.E. 2d 822 .

In my view the operative facts of the case sub judice are indistinguishable from those in Walston and are very close to those of Morrison and Hansel This may be demonstrated by the following comparison of the cases:

*118 MORRISON HANSEL

FACTS

Claimant was totally disabled, her disability being due to chronic obstructive lung disease. 50 to 60 percent of her disability was due to cotton dust exposure. Cigarette smoking as a related factor was assigned an etiologic contribution to her total lung disease of 40 to 50 percent. There was no contribution to her disability from her phlebitis, diabetes, sinusitis, or rhinitis. There was other medical testimony that up to 20 percent of her disablement resulted from an occupational disease.

Claimant had a pattern of chronic obstructive lung disease, the components of which were asthma, chronic bronchitis and byssinosis. Every person with asthma will react to cotton dust. Cigarette smoking is certainly a major contributing factor to chronic bronchitis. Diagnosis of byssinosis was made on the basis of chronic obstructive lung disease in a patient with a typical work history of byssinosis and presumably has had exposure to cotton textile dust over a period of time. No determination was made as to the extent of the condition or the weight added to its presence because the symptoms could be explained by the other two conditions.

FINDINGS

Claimant suffered from chronic obstructive lung disease ... 50 to 60 percent of her incapacity to work resulting from the disease was caused by exposure to cotton dust while the balance was due to diseases and conditions which were not caused, aggravated, or accelerated by exposure to cotton dust. Another opinion is that she is only 20 percent incapacitated for work and exposure to cotton dust could have caused, aggravated or accelerated as much as 20 percent or as little as none. Phlebitis, varicose veins and diabetes constitute an added factor in causing her incapacity and were not caused, aggravated or accelerated by exposure to cotton dust. That part of claimant’s lung disease which is related to her employment is not an ordinary disease of life to which the general public is equally exposed. Claimant is only partially incapacitated for work as a result of conditions which were caused or aggravated or accelerated by exposure to cotton dust.

Claimant has both asthma and byssinosis which are causing her respiratory impairment, which is severe and irreversible. She has byssinosis as a result of her exposure to cotton dust in her employment and this is partly responsible for her disability.

HOLDING

The Commission’s conclusion that claimant was entitled under G.S. 97-30 to compensation for a 55 percent partial disability is correct. The award must be based on that portion of a pre-existing, non-disabling, non-job-related condition that is aggravated or accelerated by an occupational disease.

The Court reiterated its position in Morrison and held that the medical evidence in the record was not sufficiently definite as to the cause of claimant’s disability to permit effective review. The case was remanded.

*119 WALSTON RUTLEDGE

FACTS

Claimant was treated for pulmonary emphysema (chronic pulmonary obstructive disease — pulmonary fibrosis). He was diagnosed as having chronic bronchitis, emphysema, possible intrinsic asthma, and possible byssinosis. Cigarette smoking would most likely play a part in his pulmonary disability. It was the primary etiological agent. He did not have a classical history of byssinosis. With intrinsic asthma he could have noticed an aggravation of his symptoms by cotton dust without necessarily invoking the diagnosis of byssinosis. Exposure to cotton dust could have played a role in the causation of his pulmonary problems, contributory rather than cause and effect.

Claimant was diagnosed as having chronic obstructive pulmonary disease representing a combination of emphysema, and chronic bronchitis. Cigarette smoking is a very important, often the primary cause of chronic obstructive pulmonary disease. It was one of the more probable causes of claimant’s disease. Recurrent infection also played a prominent role. She did not give a classical history of byssinosis. It was not possible to rule out cotton dust as playing some role. Exposure to cotton dust was probably a cause of the lung disease. Textile workers are at an increased risk of contracting chronic obstructive pulmonary disease (includes pulmonary emphysema, chronic bronchitis and possibly asthma).

FINDINGS

During the period beginning 1962 to retirement claimant has been ill due to bronchitis, emphysema, asthma, and chronic pulmonary fibrosis. From an examination, the physician gained the impression that he might also suffer from possible byssinosis. His symptoms appear to be clearly related to pulmonary emphysema and chronic bronchitis and may be, at least in part, related to cigarette smoking. With intrinsic asthma he could have noticed an aggravation of his symptoms by dust in the mill without necessarily invoking the diagnosis of byssinosis. The history of byssinosis is somewhat equivocal.

Cigarette smoking and recurrent infection have played prominent roles in the pulmonary impairment. Cotton dust may aggravate it, but since claimant was showing her symptomatology in problems prior to her employment with defendant employer, exposure at defendant employer has neither caused nor significantly contributed to her disease. She has not contracted chronic obstructive lung disease as a result of any exposure while working with defendant employer.

HOLDING

The Commission was correct in concluding that claimant did not have an occupational disease. Substantially all of the competent medical evidence tended to show that he suffered from several ordinary diseases of life to which the general public is equally exposed, none of which were caused, aggravated or accelerated by an occupational disease.

*120 The fallacy of the “significant contribution principle” and the majority’s disregard of the causal effect of non-occupational factors, arises from the failure to attach significance to the following facts:

I. “Chronic obstructive lung disease” is not a specific disease but rather a term which describes one or a combination of several obstructive pulmonary diseases including chronic bronchitis, emphysema, asthma (ordinary diseases of life), and byssinosis (the only such component which is occupational in origin).

II. Medical science has no reliable means of distinguishing the cotton-dust-related occupational disease of byssinosis in its chronic phase from other obstructive pulmonary diseases caused by non-occupational factors.

III. Physicians rely primarily on the “classical history” of byssinosis in diagnosing that occupational disease. No such history was present here.

IV. Where, as in the present case, claimant’s obstructive lung disease is not solely due to byssinosis, but in fact the byssinosis component is absent, there can be no causal connection between claimant’s lung disease and her disability. If nonoccupational disease components are present and these components are aggravated or accelerated by an occupational disease, it must then be determined what percentage of claimant’s disability is due to the non-occupational diseases which were aggravated or accelerated by an occupational disease or by causes and conditions characteristic of and peculiar to the workplace. Hansel v. Sherman Textiles, 304 N.C. 44 , 283 S.E. 2d 101 .

V. At least one component of claimant’s obstructive lung disease, emphysema, was not aggravated or accelerated to any degree by her exposure to cotton dust.

VI. While claimant’s disability was due in part to her lung disease, the components of which were pulmonary emphysema and chronic bronchitis, her diagnosis also included several significant non-lung related diseases and conditions including “possibly arteriosclerotic heart disease with angina pectoris and congestive heart failure which was then compensated, migraine, urinary incontinence of undetermined etiology, arthralgia of the back and fingers of undetermined etiology and hypertriglyceredema.”

*121 I now address each of the six factors seriatim:

I

The case at bar cannot be distinguished from Morrison , and Hansel , by the “word trick” of saying, as does the majority opinion, that in those cases the Court’s emphasis was on “byssinosis” whereas here the emphasis is on “chronic obstructive lung disease.” If one examines the medical testimony in the cases rather than the “emphasis of the court,” it is apparent that no such distinction is justified. Even a cursory reading of the summary of the cases reveals the lack of distinction urged by the majority. The majority opinion here simply mischaracterizes Morrison and Hansel as being “byssinosis” cases and thus somehow different from “chronic obstructive lung disease cases.”

“Chronic obstructive lung disease” is not a specific “disease” in and of itself. It is merely a shorthand description of one or a combination of several obstructive pulmonary diseases which may include, but may not be limited to, chronic bronchitis, emphysema, asthma, byssinosis, etc., which have similar pathologic results such as tightness in the chest, shortness of breath, small airway obstruction and production of sputum.

The majority opinion does however correctly state the holding of the two cases as follows:

Thus both Morrison and Hansel hold that when byssinosis is the occupational disease in question and causes a worker to be partially physically disabled, and other infirmities, acting independently of and not aggravated by the byssinosis, also cause the worker to be partially physically disabled, the worker is entitled to compensation for so much of the incapacity for work as is related to the physical disability caused by the occupational disease.

What the majority opinion fails to recognize is that the same holding applies whether we use the term “byssinosis” or substitute therefor the words “chronic obstructive lung disease.” It is clear from the facts in Morrison and Hansel that this Court was indeed addressing itself in both those opinions to “chronic obstructive lung disease.”

*122 II

In the records of cases which reach this Court we are repeatedly told by medical experts that the symptoms of cotton-dust-related occupational disease (ie. byssinosis) are generally the same as those of ordinary diseases of life caused by nonoccupational factors. A chronically disabled victim of byssinosis exhibits the same breathing difficulties as a person who has never been exposed to cotton dust but who has asthma, chronic bronchitis or emphysema. As pointed out by the majority opinion, the respiratory systems of both will appear the same on autopsy. What the majority opinion fails to point out is that both will look similar on x-ray film and they will perform the same way on pulmonary function tests. The truth is simply that medical science has no reliable means of distinguishing the cause of the disease in its chronic phase.

As pointed out by the majority opinion, Dr. Reginald T. Harris, also a pulmonary specialist and, like Dr. Williams, a member of the Industrial Commission’s Textile Occupational Disease Panel, testified in Hansel that “[p]eople who have byssinosis for many years, have a lung disease that is indistinguishable from chronic bronchitis.” Hansel v. Sherman Textiles, 304 N.C. at 57, 283 S.E. 2d at 108 . In the case before us, Dr. Williams testified that it is possible for byssinosis “to progress into a chronic phase which is indistinguishable from other chronic obstructive pulmonary disease.”

Dr. Williams testified in Walston that:

There is not specifically any objective finding to say that a man does or doesn’t have byssinosis that you could put your finger on, such as a biopsy or autopsy, such as with silicosis and asbestosis, although in the early stages one can demonstrate a reactivity to the dust by doing pulmonary function studies before and after six hours exposure to the work environment. But in the latter stages, such as one might see with chronic obstructive pulmonary disease, this is no longer valid and these are not specific diagnostic criteria. Therefore, any diagnosis I am making of Mr. Walston is predicated almost entirely, if not entirely, upon his history and subjective findings.

R. p. at 18.

*123 Ill

In Walston Dr. Williams explained the type of “classic history” usually employed and primarily relied upon in diagnosing byssinosis:

For the record, ‘classic history’ of byssinosis, that of textile workers, is that after having worked for several years, the worker begins to notice symptoms on Monday morning, after being back at work for a short period of time, symptoms of chest tightness, shortness of breath, sometimes coughing, wheezing and sputum production, the symptoms usually being improved on Tuesday and the rest of the week, but after a number of years the symptoms become more persistent throughout the rest of the week, until finally the symptoms are more or less chronic. This history is part of the diagnosing of byssinosis.

Walston v. Burlington Industries, 304 N.C. at 672-73, 285 S.E. 2d at 824. In Walston Dr. Williams, referring to the claimant Walston, testified “[t]his man did not have a completely classical history.” Id. at 673, 285 S.E. 2d at 824. In the case now before us, referring to the claimant Rutledge, he testified “[i]t is not possible to completely exclude cotton dust as playing some role in causing an irritative bronchitis but she does not give a classical history of byssinosis.”

IV

With such heavy dependence on the “classical history” in diagnosing byssinosis and the total absence of such a history by Mrs. Rutledge, Dr. Williams’ reluctance to state unequivocally that the inhalation of cotton dust “caused” claimant’s chronic obstructive lung disease is understandable. He would only testify, as the majority readily admits, that Mrs. Rutledge’s exposure to cotton dust “probably was a cause” of her chronic obstructive lung disease and that “her impairment with respect to the ability to perform labor is related to her pulmonary disease.” Even these tentative statements were, as the majority admits, based upon a hypothetical which omitted a factor which Dr. Williams considered “very important,” i.e., some approximately thirty years of relatively heavy cigarette smoking. He subsequently testified:

*124 When I was examining Mrs. Rutledge I got a history from her. This history included her history as to smoking. She gave me the history that she began smoking at age 15 and averaged one pack of cigarettes daily until she stopped smoking in February, 1979. I think cigarette smoking is a very important, often the primary cause, of chronic obstructive pulmonary disease. Based upon the facts that Ms. Hudson has given me and based upon my examination and particularly upon the history of cigarette smoking that Mrs. Rutledge gave me it is my opinion satisfactory to myself to a reasonable degree of medical certainty is that her history of cigarette smoking could or might have been the cause of her pulmonary emphysema and chronic bronchitis. Based upon my examination and these facts, I would say it was one of the more probable causes. This is after taking into consideration her exposure to cotton dust.

(Emphasis added.)

It should be noted that while Dr. Williams said claimant’s exposure to cotton dust “probably was a cause,” it is obvious that he felt, and he so testified, that cigarette smoking was “one of the more probable causes.” From this evidence emerges the indisputable fact that under our holdings in Morrison and Hansel , this case could at best be remanded for findings as to the percentage contribution of non-occupational diseases and factors to claimant’s disability. However, to its new concept of “significant contribution” the majority adds that there can be full recovery “even if other non-work-related factors also make significant contributions, or were significant causal factors.” This latter provision flies fully in the face of our recent decisions in Morrison, Hansel and Walston and essentially overrules those cases.

I do not wish to be interpreted as saying that a claimant suffering from chronic obstructive lung disease may never recover for disability resulting from that condition. Chronic obstructive lung disease may be compensable in whole or in part if: (1) it is due solely to byssinosis or (2) byssinosis is one of several components (together with other ordinary diseases of life such as chronic bronchitis, asthma, emphysema) and conditions of the workplace materially aggravate or accelerate these other components, in which case it must be determined (a) what percentage *125 of the disability is compensable due to byssinosis, (b) what percentage is compensable due to the other components which have been materially aggravated or accelerated by the inhalation of cotton dust and (c) what percentage is due to non-compensable causes unrelated to the work environment (for instance, recurring infections, cigarette smoking, etc.).

V

At least one component of claimant’s obstructive lung disease, emphysema, was not aggravated or accelerated to any degree by her exposure to cotton dust. It seems to be widely accepted by the medical experts in the field that the inhalation of cotton dust aggravates pre-existing bronchitis but does not aggravate emphysema. Perhaps this can be demonstrated by a quotation from a paper presented at the International Conference on Byssinosis by Phillip C. Pratt, M.D., F.C.C.P. of the Department of Pathology, Durham Veterans Administration and Duke University Medical Center, Durham: 1

It seems important to identify emphysema in the cotton worker population. Bronchitis and emphysema each can cause COPD and enhance the degree of obstruction produced by the other. The lesions in bronchi shown here to be significantly associated with cotton mill work are generally agreed to be morphologic correlates of clinical bronchitis. Since they represent hyperplastic or metaplastic epithelial changes occurring in response to an irritant in the mill atmosphere, and since such epithelial changes are well known from studies of exsmokers to be at least partially reversible, with associated functional improvement, one might predict that removing from the mill a symptomatic cotton worker whose lungs were not emphysematous should result in gradual restoration toward normal epithelium and reduction of the symptoms. Such a sequence of events has been observed repeatedly, although not frequently reported.

*126 On the other hand, the destructive lesions of emphysema are not reversible. Thus, removal of such a patient from the mill may not result in disappearance of the symptoms, and the functional impairment may well persist and produce permanent disability. However, since the mill exposure could not have been responsible for the emphysema, the irreversible impairment should not be attributed to the occupational exposure.

Second, can any rationale be proposed to explain the fact that cotton mill work does not cause pulmonary emphysema? It is now recognized that the destructive process involving alveolar walls in emphysema is probably a local effect produced by proteolytic enzymes probably derived from inflammatory cells. Cigarette smoke is almost ideally suited to provide the stimulus for such cellular reaction in alveoli, since the particulate material is in such a uniform minute size range, namely 0.2 to 1 [microns]. Thus an appreciable portion of the total material can reach alveoli both by mass movement of inhaled air and by diffusion. In contrast, the size range of fibers and particles in a mill atmosphere ranges from 0.3 to 25 [microns], with a median size of 7 [microns]. The particles are more likely than cigarette smoke to be impinged onto bronchial surfaces, and the smaller end of the size range, which can move by diffusion, constitutes only a minute portion of the total mass. Thus, little or no cotton dust can reach the alveoli to produce the excessive cellularity that has been shown to occur in cigarette smokers. The absence of excess pulmonary pigmentation in the lungs of the cotton workers . . . supports this reasoning.

This being so it must be conceded that whatever portion of the claimant’s chronic obstructive pulmonary disease is due to emphysema, it was not contributed to in any degree by her exposure to cotton dust. This alone demonstrates the fallacy of grouping all lung diseases under one name, “chronic obstructive lung disease,” and making that “disease” compensable if any part of it was “significantly contributed” to by the inhalation of cotton dust.

*127 VI

The majority today departs from our longstanding precedent by allowing recovery of benefits when causes and conditions of the workplace “significantly contribute” to any ordinary disease of life which results in a disability. An attempt is made to justify this departure from our statute and the case law by this statement from the majority opinion:

All ordinary diseases of life are not excluded from the statute’s coverage. Only such ordinary diseases of life to which the general public is exposed equally with workers in the particular trade or occupation are excluded. Booker v. Duke Medical Center, supra, 297 N.C. at 472-75 , 256 S.E. 2d at 198-200 . Thus, the first two elements are satisfied if, as a matter of fact, the employment exposed the worker to a greater risk of contracting the disease than the public generally. Id. ‘The greater risk in such cases provides the nexus between the disease and the employment which makes them an appropriate subject for workmen’s compensation.’ Id. at 475 , 256 S.E. 2d at 200 .

The majority obviously believes that the testimony of Dr. Williams to the effect that the mere exposure to cotton dust creates an increased risk of lung disease somehow establishes that all of Mrs. Rutledge’s diseases (including, we must assume, her many non-lung related diseases) are “occupational diseases” provided any “significant contribution” to those diseases by the cotton dust can be established. This position was rejected by the majority opinion in Morrison . I find it shocking that a disability from this range of diseases and conditions, most of which are ordinary diseases of life, would be fully compensable because of the “significant contribution” to only the lung conditions by the inhalation of cotton dust. While her non-lung related conditions did not contribute to her pulmonary conditions, it is inescapable that they contributed to her disability.

Nor do I find it unusually significant, as does the majority, that Dr. Williams was of the opinion that textile workers are “at an increased risk of contracting chronic obstructive pulmonary disease,” which according to Dr. Williams includes “pulmonary emphysema, chronic bronchitis and possibly asthma” as well as byssinosis. We are repeatedly told by expert medical witnesses *128 that the same is true of cigarette smokers and others who may be in no way connected with the textile industry. We are even told that the same is true of those exposed to concentrations of ordinary household or yard dust. It is interesting that in this very case Dr. Williams testified: “I think that exposure to any type of dust in someone with pre-existing chronic bronchitis could have some aggravating effect on the underlying condition.” He also said “I stated that exposure to any kind of dust in an individual with underlying lung disease would have an aggravating effect.” (Emphasis added.) It is indeed on the basis of the last quoted sentence that the majority opinion characterizes Dr. Williams as saying “that such exposure as she had at Kings Yarn ‘could have some aggravating effect on [her] underlying condition.’ ” As is obvious, this characterization of that testimony is completely misleading.

This particular case is one wherein the claimant has failed to meet her burden of proof that she has a compensable claim. Henry v. Leather Co., 231 N.C. 477 , 57 S.E. 2d 760 (1950). The evidence does not establish the claim. In cases where there is continuing medical difficulty in determining the etiology of disease and injury, compensation awards cannot be sustained in the absence of expert medical testimony on the matter of causation. See Click v. Freight Carriers, 300 N.C. 164 , 265 S.E. 2d 389 (1980); see also Gillikin v. Burbage, 263 N.C. 317 , 139 S.E. 2d 753 (1965). In the present case, the expert testimony does not establish the claim of occupational disease. See Walston v. Burlington Industries, 304 N.C. 670 , 285 S.E. 2d 822 .

The majority opinion attempts to distinguish the case sub judice from Walston because in Walston the term “possible” is used while the word “probable” is used in the present case. It is a distinction without a difference. A mere “probability” of causation is no more substantial or sufficient than a mere “possibility.” The fact that the medical witness testified that claimant’s exposure to cotton dust in her twenty-five years of employment “probably” was a cause of her chronic obstructive lung disease but that “cigarette smoking” was one of the more probable causes . . . after taking into consideration her exposure to cotton dust (emphasis added) does not take the causation effect out of the realm of speculation. In Walston Dr. Williams testified that claimant’s exposure to cotton dust “could possibly have played a role in the *129 causation of his pulmonary problems” whereas here Dr. Williams testified that such exposure “probably was a cause.” (Emphasis added.) Moreover, as to Mrs. Rutledge, Dr. Williams further testified that “[i]t is not possible to completely exclude cotton dust as playing some role in causing an irritative bronchitis but she does not give a classical history of byssinosis.” This latter statement, of course, is essentially the same as the statement in Walston that “[t]his man did not have a completely classical history.”

Claimant has failed to prove that an “occupational disease” caused her disability. She has failed to show that her “chronic obstructive lung disease” is an occupational disease within the meaning of our statute. Had this case been tried and decided on the basis of aggravation and acceleration of a pre-existing condition by causes and conditions of the workplace, an award of compensation benefits might have been justified. The theory insisted upon by the claimant, and adopted by the majority, that her ordinary diseases of life were somehow transformed into an “occupational disease” by the “significant contribution” of causes and conditions of the workplace, is, to say the least, new law in this jurisdiction and will no doubt come as a shock to our legislators as somehow being within their intent.

Surely some assessment must be made of the percentage of claimant’s disability, if any, due to her emphysema as well as her arteriosclerotic heart disease, angina pectoris, congestive heart failure, migraine, arthralgia, and hypertriglyceredema.

I believe this Court in Hansel (where there were only lung conditions) gave the Industrial Commission good advice as to what it must consider in cases like this:

In cases in which a claimant has other infirmities related solely to the lungs or respiratory system, the Commission should, as a matter of course, consider whether claimant’s disablement (i.e. inability to work and earn wages) results from aggravation of those other non-occupational diseases or infirmities by causes and conditions peculiar to claimant’s employment.

*130 In order for the Court to determine whether the Commission’s findings and conclusions are supported by competent evidence, the record before us must [contain] medical testimony to indicate answers to the following questions:

(1) Is plaintiff totally or partially incapacitated to work and earn wages? If partial, to what extent is she disabled; ie., what is the percentage of her disability?

(2) What disease or diseases caused this disability?

(3) Which of the plaintiffs disabling diseases are occupational in origin, ie., which diseases are due to causes and conditions which are characteristic of and peculiar to plaintiffs occupation as distinguished from ordinary diseases of life to which the general public is equally exposed outside of the employment?

(4) Does plaintiff suffer from a disabling disease or infirmity which is not occupational in origin, ie., which is not due to causes and conditions characteristic of and peculiar to plaintiffs occupation as distinguished from ordinary diseases of life to which the general public is equally exposed outside of the employment?

If so, specify the non-occupational disease(s) or infirmities?

(5) Was plaintiffs non-occupational disease(s) or infirmity aggravated or accelerated by her occupational disease(s)?

(6) What percentage of plaintiffs incapacity to work and earn wages results from (a) her occupational disease(s) or (b) her non-occupational disease(s) which were aggravated or accelerated by her occupational disease(s)?

(7) What percentage of plaintiff’s incapacity to work and earn wages results from diseases or infirmities which are non-occupational in origin?

Hansel v. Sherman Textiles, 304 N.C. at 53, 58-59, 283 S.E. 2d at 106, 109 (1981).

The case should not be remanded for the purpose of applying the new “substantial contribution” principle — if it is to be remanded at all it should be for the purpose of apportionment of *131 Mrs. Rutledge’s disability to work-related and non-work-related causes.

I agree with the majority’s conclusion that it is not necessary that Mrs. Rutledge show that the conditions of her last employer’s workplace were the sole causes of her disability and that it is only necessary for her to show that the conditions of her last employer’s workplace “augmented the disease to any extent, however slight.” 2 I vote to affirm the opinion of the Court of Appeals and to modify it to the extent necessary to correct this error.

Chief Justice Branch and Justice COPELAND join in this dissent.

. An International Conference on Byssinosis, attended by experts on the subject from throughout the world was held in Birmingham, Alabama, in April, 1981. Some approximately thirty-five of the papers presented at that conference are collected and published in the official publication of the American College of Chest Physicians — CHEST for Pulmonologists, Cardiologists, Cardiothoracic Surgeons and Related Specialists, Volume 79/number 4/April 1981 Supplement. Dr. Pratt’s article appears at page 49S and the quotation appears on page 51S.

. I must point out, however, what I consider to be a significant omission in the majority’s statement that “She need only show: (1) that she has a compensable occupational disease and (2) that she was ‘last injuriously exposed to the hazards of such disease’ in defendant’s employment.” The omission from (1) that the occupational disease be the cause of her disability is fatal and will come back to haunt us. The first requirement should be accurately stated as follows: “that she has an occupational disease which caused her disability.”