Justice MEYER dissenting.

Chief Justice BRANCH and Justice COPELAND join in this dissent.

EXUM, Justice.

The questions for decision are whether the Industrial Commission applied the wrong legal standard in its order denying benefits to claimant and whether there is evidence from which the Commission could have made findings, using the correct legal standard, that would support a conclusion that claimant contracted an occupational disease. We answer both questions affirmatively.

After hearing evidence for claimant and defendants, Deputy Commissioner Denson concluded that claimant had not contracted an occupational disease. This conclusion was based in part on the following factual findings, which are summarized unless quoted, to which no exception has been taken: Plaintiff, born 8 August 1935, has a tenth grade education and now lives in Georgia. She has smoked cigarettes from about age fifteen until February 1979 at the rate of approximately one pack per day. She has worked for four textile mills: (1) United Merchants in Buffalo, South Carolina, from 1953 until 1971 as a weaver; (2) Milliken at Union, South Carolina, from 1971 to 1973 as a "dry cleaner"; (3) Alco Manufacturing, Rockingham, North Carolina, from 1975 to 1976 as a weaver; and (4) for defendant from 25 October 1976 until 12 January 1979 as a winder and then as a spinner. She was absent "for bronchitis" from 28 January 1977 until 13 May 1977. She "retired" on 12 January 1979.

All the plants where plaintiff worked "had a lot of cotton dust and lint" but defendant's premises, both in the weaving and spinning areas, were "relatively clean." Defendant's mill processed essentially 50 percent cotton blend materials and occasionally blends made of even a smaller percentage of cotton. "Although there was respirable cotton dust in [defendant's] weave room, there was much less than . . . in other premises." Plaintiff began developing a cough at work in 1969 or 1970. "[H]er cough was associated with her presence at work. Her shortness of breath became severe in December of 1976 and she has had various bouts with it since that time having to be out of work. . . . Plaintiff suffers from chronic obstructive pulmonary disease [with elements] of pulmonary emphysema and chronic bronchitis. . . . Plaintiff is disabled, because of her pulmonary impairment from all but sedentary . . . work which must be in a clean environment because of her reaction to cotton dust and other such irritants."

Deputy Commissioner Denson also made certain findings to which claimant excepted. The first was that in 1971 claimant "began developing a shortness of breath." Second was the following which the Deputy Commissioner included in the findings of fact:

6. . . . Cigarette smoking and recurrent infection have played prominent roles in the pulmonary impairment. Cotton dust may aggravate it, but since plaintiff was showing her symptomatology in problems prior to her employment with defendant employer, exposure at defendant employer has neither caused not significantly contributed to plaintiff's chronic obstructive pulmonary disease.

. . . .

8. Plaintiff has not contracted chronic obstructive lung disease as a result of any exposure while working with defendant employer. [Emphasis added.]

The Full Commission, with one commissioner dissenting, adopted Deputy Commissioner Denson's findings, conclusions, opinion and award as its own.

The Court of Appeals concluded that although the Commission erred "in requiring plaintiff to prove that her last employment was the cause of her occupational disease," the error was harmless since there was insufficient evidence before the Commission to show that plaintiff had ever contracted an occupational disease during her working life. Rutledge v. Tultex Corp./Kings Yarn, 56 N.C. App. 345, 350, 289 S.E.2d 72, 74 (1982).

Because of the italicized portions of findings 6 and 8, it does appear that the Commission thought that in order successfully to claim against defendant, claimant's last employer, claimant must establish that her exposure there either caused or significantly contributed to her chronic obstructive pulmonary disease. This is not the law. That part of G.S. 97-57 pertinent to this case provides:

In any case where compensation is payable for an occupational disease, the employer in whose employment the employee was last injuriously exposed to the hazards of such disease, and the insurance carrier, if any, which was on the risk when the employee was so last exposed under such employer, shall be liable.

Under this statute, consequently, it is not necessary that claimant show that the conditions of her employment with defendant caused or significantly contributed to her occupational disease. 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 statutory terms "last injuriously exposed" mean "an exposure which proximately augmented the disease to any extent, however slight." Haynes v. Feldspar Producing Company, 222 N.C. 163, 166, 169, 22 S.E.2d 275, 277, 278 (1942).

Haynes was a silicosis case. The evidence showed that claimant worked in North Carolina feldspar mines for about twenty-eight years. From 1927 to 1940 he worked for Tennessee Mineral Corporation where he was constantly exposed to "silica dust." He then worked for defendant producing company from 24 September 1940 until 24 January 1941 where he was also exposed to dust from feldspar and flint. On 21 January 1941 Dr. T. F. Vestal diagnosed plaintiff as having "moderately advanced silicosis with probable infection [which] may be of a tuberculous nature." Plaintiff worked no more after 24 January 1941. Further evidence at the hearing was that samples taken at defendant's mine showed sufficient concentrations of dust "to constitute a silicosis hazard." Dr. Vestal testified that he had examined plaintiff in 1936, 1937, 1938 and 1940. By 1937 plaintiff "had early silicosis" and by 28 November 1940 plaintiff "had moderately advanced silicosis with probable infection." Dr. Vestal also testified that plaintiff was "disabled to perform normal labor as a mucker." Dr. Vestal could not state whether plaintiff's silicosis advanced any at all between the time that he entered the defendant's employment and the time that he left it. He was asked whether plaintiff was "last injuriously exposed" to the hazards of silicosis within the meaning of the predecessor to G.S. 97-57. He was told by the Commission that the phrase "last injuriously exposed" as used in the statute "meant an exposure which proximately augmented the disease to any extent, however slight." Id. at 166 22 S.E.2d at 277. The doctor then replied, to a hypothetical question, "You haven't left me much leeway. I have an opinion that it did constitute an injurious exposure." Id. at 167, 22 S.E.2d at 277. The Industrial Commission gave an award against defendant.

On defendant's appeal it contended there was no evidence to support the Commission's finding that claimant was injuriously exposed to the hazards of the disease during his short employment with defendant. This Court affirmed the Commission. The Court held that "the definition [of last injuriously exposed] supplied by the Commission was substantially correct." Id. at 169, 22 S.E.2d at 278. The Court said, id. at 170, 22 S.E.2d at 279:

Perhaps on a comparative basis, the chief responsibility for plaintiff's condition morally rests upon his Tennessee employers; but not the legal liability. It must have been fully understood by those who wrote the law fixing the responsibility on the employer in whose service the last injurious exposure took place, that situations like this must inevitably arise, but the law makes no provision for a partnership in responsibility, has nothing to say as to the length of the later employment or the degree of injury which the deleterious exposure must inflict to merit compensation. It takes the breakdown practically where it occurs — with the last injurious exposure.

The Court of Appeals correctly concluded, therefore, that the Industrial Commission applied the wrong legal standards to this claim.

We hold that the Court of Appeals erred, however, in concluding that there is no evidence that plaintiff had contracted an occupational disease. We think there is evidence from which the Industrial Commission could have made findings which in turn would have supported a conclusion that claimant's chronic obstructive lung disease was an occupational disease. Dr. Williams, after a lengthy recitation of certain assumed facts, was asked the following question:

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?

When he replied, "Yes," the following colloquy occurred:

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.

In putting the hypothetical question to Dr. Williams, claimant's counsel made no reference in the assumed facts to claimant's having smoked cigarettes regularly for most of her life. Defendant argues that because of this omission we should not consider Dr. Williams' answer to the hypothetical as competent evidence. We reject this argument. First, defendants did not object to the question, nor did they move to strike the answer. Second, the answer is competent despite the omission of claimant's smoking habit from the assumed facts. Dr. Williams was not asked to express his opinion based solely on the assumed facts; he was asked to base it also on his own examination and testing of claimant — an examination which included the taking of claimant's history which in turn revealed to Dr. Williams that she had a smoking habit. Indeed, Dr. Williams' very next statement on cross-examination was:

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.

Further, the omission of a material fact from a hypothetical question does not necessarily render the question objectionable or the answer incompetent. Dean v. Carolina Coach Co., 287 N.C. 515, 215 S.E.2d 89 (1975); State v. Stewart, 156 N.C. 636, 72 S.E. 193 (1911); 1 Brandis, Stansbury's N.C. Evidence 137 (2d rev. ed. 1982). It is left to the cross-examiner to bring out facts supported by the evidence that have been omitted and thereby determine if their inclusion would cause the expert to modify or reject his earlier opinion. Id.

Indeed, defendants on cross-examination proceeded to do precisely this and succeeded in having Dr. Williams testify:

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.

The thrust of Dr. Williams' entire testimony, then, seems to be that both her exposure to cotton dust over her working life and her cigarette smoking were causative factors in claimant's chronic obstructive lung disease. He also said other components of the lung disease were "pulmonary emphysema" and "chronic bronchitis" and that "chronic obstructive lung disease includes pulmonary emphysema, chronic bronchitis, and possibly asthma."

After relating his considerable experience in the treatment and study of respiratory diseases among textile workers, such as claimant here, Dr. Williams testified that these workers are "at an increased risk of contracting chronic obstructive pulmonary disease." Dr. Williams also testified that when claimant began such work in October 1976 "she was suffering from pulmonary emphysema, chronic bronchitis and chronic obstructive pulmonary disease . . . caused by circumstances which existed prior to her employment by Kings Yarn." Although testifying that claimant's exposure to cotton dust at Kings Yarn's plant would have "minimal" effect on her condition and that she would not have had there a "very substantial exposure" to cotton dust, Dr. Williams did say that such exposure as she had at Kings Yarn "could have some aggravating effect on [her] underlying condition" and that removal from the Kings Yarn "environment would probably improve her symptoms . . . primarily, her symptoms of cough." Dr. Williams testified flatly that claimant's exposure to respirable cotton and synthetic dust at Kings Yarn "would have aggravated her condition." Medical records offered in evidence tended to show that claimant's lung function had decreased some 25 to 30 percent during the period from January 1977 to March 1979, while she worked for defendant employer.

Claimant, herself, described in some detail the dusty conditions under which she had worked for twenty-five years in various textile mills. She said she developed a breathing difficulty in 1971 which by 1977 had begun "affecting my ability to do my job" because it caused her to be too fatigued to work. She said she stopped work in January 1979 "because I was unable to perform my duties on my job. From tiredness, short of breath, cold sweats, headaches and I felt I was not being fair to myself or the company. I did not just quit, I was advised by my doctor . . . to quit." Claimant testified that when she quit work "my symptoms were difficulty breathing, wheezing, tiredness, cold sweats, [and] stiffness in my neck. I coughed so hard until the [neck] muscle, you know, it's ruptured in the left side." By January 1979 claimant said that she did not have the "strength or ability to do my housework, my shopping or any of those things. I am able to do my daily routine, I can make a bed, at which time I have to rest. . . . I help [my mother] watch dinner and the rest of my day consists of soap operas and rest. I crochet, anything to pass time. I just cannot be exerted because if I do I just don't have the breath. I do drive. I don't have any training for jobs besides working in the mill."

For a disease to be occupational under G.S. 97-53 (13) it must be (1) characteristic of persons engaged in the particular trade or occupation in which the claimant is engaged; (2) not an ordinary disease of life to which the public generally is equally exposed with those engaged in that particular trade or occupation; and (3) there must be "a causal connection between the disease and the [claimant's] employment." Hansel v. Sherman Textiles, 304 N.C. 44, 52, 283 S.E.2d 101, 105-06 (1981); Booker v. Duke Medical Center, 297 N.C. 458, 468, 475, 256 S.E.2d 189, 196, 200 (1979). To satisfy the first and second elements it is not necessary that the disease originate exclusively from or be unique to the particular trade or occupation in question. 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.

This Court has had little difficulty either articulating or applying the first two standards in occupational disease cases generally. They were articulated and properly applied in Booker, a hepatitis case, and reiterated and properly applied in Hansel, a lung disease case. We have had some difficulty in the lung disease cases, however, in both articulating and applying a factual standard for determining whether there is an appropriate causal connection between the employment and the disease. Compare the majority and dissenting opinions in Morrison v. Burlington Industries, 304 N.C. 1, 282 S.E.2d 458 (1981), and Hansel v. Sherman Textiles, supra, 304 N.C. 44, 283 S.E.2d 101. See also Walston v. Burlington Industries, 304 N.C. 670, 285 S.E.2d 822, amended on rehearing, 305 N.C. 296, 285 S.E.2d 822 (1982).

This difficulty in the lung disease cases stems largely from the complex medical picture often presented by chronic obstructive lung disease and chronicled in the medical testimony in Walston, Hansel and Morrison. This disease, as we understand it from the medical testimony presented in these cases and the literature to which we have been referred, see, e.g., Bouhuys, Schoenberg, Beck and Schilling, Epidemiology of Chronic Lung Disease in a Cotton Mill Community, Service Volume Five of Traumatic Medicine and Surgery for the Attorney 607, reprinted from Lung — An International Journal on Lungs, Airways, and Breathing, 154 (3): 167-86 (1977), has several components. Some of these components are seemingly not, in their incipience at least, work related, for example, bronchitis, emphysema and asthma; while at least one component, i.e., byssinosis, is work related. Byssinosis may be understood as the adverse effect on the lungs resulting from the inhalation of cotton dust, a substance generally present in the work environment of textile mill employees. Other complicating factors are that chronic obstructive lung disease may apparently be brought on by just the continuous inhalation of cotton dust, just the continuous inhalation of other substances, such as cigarette smoke, or by the inhalation of both kinds of substances together. It is apparently medically impossible even on autopsy objectively to distinguish the effect on the lungs of cigarette smoke inhalation and the inhalation of cotton dust, or between the effects of bronchitis and the inhalation of these substances. Thus when a textile worker who is also an habitual cigarette smoker and who suffers from bronchitis, emphysema, or asthma, contracts disabling chronic obstructive lung disease, the medical experts and, in turn, the Commission and the courts are presented with a difficult factual question on the causation issue. Since courts generally develop principles of law to deal as justly as possible with the facts of given cases, complex facts which the experts themselves have difficulty unraveling make the articulation of appropriate legal principles correspondingly difficult for the courts.

In Morrison claimant was physically disabled for all but sedentary work, but the Commission, after concluding that only 55 percent of her disability was caused by her occupational disease, which the Commission saw as only byssinosis, entered an award for 55 percent partial incapacity for work. A majority of this Court affirmed; it, like the Commission, viewed Morrison's occupational disease as byssinosis, i.e., that part of her chronic obstructive lung disease caused by her exposure to cotton dust. The Commission found:

7. Plaintiff suffers from chronic obstructive lung disease, due, in part, to causes and conditions characteristic of and peculiar to her particular trade, occupation or employment in the textile industry. That part of her lung disease which is related to her employment is not an ordinary disease of life to which the general public is equally exposed outside of such employment.

8. Due to the chronic obstructive lung disease suffered by plaintiff, and due to her other physical infirmities, including bronchitis, phlebitis, varicose veins and diabetes plaintiff has no earning capacity in any employment for which she can qualify in the labor market.

9. The claimant is only partially incapacitated for work as a result of conditions which were caused, aggravated, or accelerated by exposure to cotton dust during the course of her employment at Burlington Industries. Although the plaintiff is totally incapacitated for work only fifty-five percent of her incapacity was caused, aggravated, or accelerated by exposure to cotton dust during the course of her employment at Burlington Industries. The remaining forty-five percent of the plaintiff's incapacity for work was not caused by an occupational disease, and was not caused, aggravated, or accelerated by an occupational disease or by exposure to cotton dust during the course of her employment at Burlington Industries.

. . . .

11. As a result of the chronic obstructive pulmonary disease caused by her exposure to cotton dust, plaintiff has only a partial incapacity for work. She has sustained a fifty-five percent loss of wage-earning capacity or ability to earn wages by reason of her cotton dust exposure.

304 N.C. at 4-5, 282 S.E.2d at 462-63 (emphasis added). Thus the Commission found that only that part of Mrs. Morrison's chronic obstructive lung disease caused by her exposure to cotton dust, i.e., her byssinosis, was an occupational disease, and that this disease caused her to suffer a fifty-five percent partial incapacity for work. It made an award for fifty-five percent partial disability, the full amount of claimant's disability which it found to have been caused by claimant's occupational disease. A majority of this Court concluded that the Commission's findings were supported by the evidence and the Court was bound by them. The majority posed the question for decision and its answer as being:

When the Industrial Commission finds as fact, supported by competent evidence, that a claimant is totally incapacitated for work and 55 percent of that incapacity is caused, accelerated or aggravated by an occupational disease and the remaining 45 percent of that incapacity for work was not caused, accelerated or aggravated by an occupational disease, must the Commission, under the Workers' Compensation Act of North Carolina, award compensation for 55 percent disability or 100 percent disability? Upon such findings of fact, our Act mandates an award for 55 percent partial disability.

304 N.C. at 6, 282 S.E.2d at 463. This Court's majority thought the evidence specifically supported the Commission's findings that only that part of Mrs. Morrison's chronic obstructive lung disease caused by her exposure to cotton dust, i.e., her byssinosis, was an occupational disease and that it was bound by this finding. It said:

The evidence in this case, especially the medical evidence, overwhelmingly supports the Industrial Commission's findings that 55 percent of Mrs. Morrison's inability to work and earn wages is caused by `chronic obstructive lung disease, due in part, to causes and conditions characteristic of and peculiar to her particular . . . employment in the textile industry,' and the remaining 45 percent is caused independently by her other physical infirmities, including chronic obstructive lung disease not caused, aggravated or accelerated by an occupational disease, as well as bronchitis, phlebitis, varicose veins and diabetes, none of which are job related and none of which have been aggravated or accelerated by her occupational disease. This Court must accept such findings as final factual truth.

304 N.C. at 6-7, 282 S.E.2d at 463.

The dissenters in Morrison believed that both the Commission and the majority had misconstrued the evidence. The dissenters argued that the Commission's finding that only that part of Mrs. Morrison's lung disease caused by her exposure to cotton dust, i.e., byssinosis, was an occupational disease was not supported by the evidence. The dissenters argued that all the evidence tended to show: (1) Mrs. Morrison's entire physical disability was caused by her chronic obstructive lung disease; (2) her byssinosis had significantly contributed to this disease; (3) her chronic obstructive lung disease was an occupational disease; (4) therefore Mrs. Morrison was entitled to an award for total disability.

Thus, 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 Hansel the Commission in a lung disease case again made an award for permanent partial incapacity for work which the Court of Appeals vacated for insufficient evidence. There was medical testimony that claimant had chronic obstructive lung disease with "three distinct syndromes" contributing to it. These "syndromes" were identified by the medical witness as asthma, byssinosis and chronic bronchitis. There was also evidence that claimant was a cigarette smoker. 304 N.C. at 55-56, 283 S.E.2d at 109.

The Commission found and concluded:

4. Plaintiff has both asthma and byssinosis which are causing her respiratory impairment. Her impairment is severe and irreversible.

5. Plaintiff has byssinosis as a result of her exposure to cotton dust in her employment with defendant-employer and this is partly responsible for her disability.

6. Plaintiff has not worked since May 5, 1977.

* * *

The foregoing findings of fact and conclusions of law engender the following additional

CONCLUSIONS OF LAW

1. Plaintiff has contracted the disease byssinosis as a result of exposure to cotton dust in her employment with defendant-employer. This disease is compensable under the provisions of G.S. 97-53 (13).

2. Defendants owe plaintiff compensation for permanent, partial disability from May 5, 1977 for her period of disability not to exceed 300 weeks. G.S. 97-30.

Id. at 47-48, 283 S.E.2d at 103 (emphasis added). This Court concluded, contrary to the Court of Appeals' decision, that the evidence was sufficient to support the findings of the Commission, stating: "We . . . find competent evidence to support the findings of the Commission, but we are unable to say that the findings justify the Commission's conclusion as to the causation and its award." 304 N.C. at 50, 283 S.E.2d at 105. The Court on this ground and also on the ground that the medical evidence was "not sufficiently definite on the cause of plaintiff's disability to permit effective appellate review," 304 N.C. at 55, 283 S.E.2d at 107, remanded the matter to the Commission for further proceedings. The Court said:

In the case before us in which the Commission made an award of compensation, there was not sufficient determination by the finders of fact, and certainly no explicit findings, upon which this Court can determine the sufficiency of the evidence to support the Commission's findings and conclusion. It is explicitly stated in the Commission's finding number 5 that plaintiff's byssinosis `is partly responsible for her disability' and thus implicit that some other disease or infirmity is likewise `partly responsible for her disability.' The evidence indicates that the other disease or infirmity is probably asthma and chronic bronchitis, although plaintiff also testified that two other doctors told her previously that she had emphysema. It also appears from the evidence that she is apparently also allergic to, among other things, dust, mold, mildew, trees, grass, animals, feathers, cotton dust, nylon dust and polyester dust. Because of the presence of these other infirmities and because this is a case of partial disability as opposed to one of total disability, it must be determined what percentage of claimant's disability is due to her occupational disease. Morrison v. Burlington Industries, 304 N.C. 1, 282 S.E.2d 458 (1981).

The medical evidence appearing in the record before this Court is not sufficiently definite on the cause of plaintiff's disability to permit effective appellate review. The only medical witness before the Commission. Dr. Harris, did not address the crucial medical question of interrelationship, if any, between plaintiff's occupational disease and her disability.

304 N.C. at 54-55, 283 S.E.2d at 107. The Court directed that at the new hearing before the Commission medical testimony be adduced to shed light on various questions dealing generally with the extent of claimant's disability; the nature of the disease or diseases causing the disability; and whether these diseases were occupational or were aggravated in such a way as to cause them to be compensable.

Again, as in Morrison, the Commission had found that claimant's byssinosis was the occupational disease which had caused claimant to be partially disabled for work. Again, a majority of the Court seemed to believe that if claimant had an occupational disease at all, it was byssinosis. The majority noted that claimant sought recovery "on the grounds that she contracted byssinosis as a result of exposure to cotton dust in the course of her employment as a textile worker in defendant's plant." Id. at 46, 283 S.E.2d at 102. The Court noted further that "[b]yssinosis is `not mentioned in and compensable under' the [Workers' Compensation] Act, except by virtue of G.S. 97-53." Id. at 51, 283 S.E.2d at 105. The Court pointed out that "neither Mrs. Hansel's asthma nor her chronic bronchitis is an `occupational disease' which standing alone is compensable." Id. at 53, 283 S.E.2d at 106 (emphasis added).

The concurring justices in Hansel doubted that medical evidence could provide the answers to several of the questions posed by the majority on the ground that these questions really constituted legal conclusions which the Commission in the first instance and this Court ultimately would have to make. Again, as in Morrison, the concurring justices believed, despite the finding of the Commission to the contrary, the evidence demonstrated that if Mrs. Hansel had an occupational disease at all, it was chronic obstructive lung disease to which Mrs. Hansel's cotton dust exposure might have significantly contributed. Again, the concurring justices believed the Commission and the majority had misconstrued the evidence.

Thus the results in both Morrison and Hansel rest on the proposition that when byssinosis is or may be 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 disabled, the worker is entitled to compensation for so much of the incapacity for work as is due to the physical disability caused by the byssinosis.

This case is the first we have considered in which the Commission has found on supporting evidence both that claimant is totally physically disabled except for sedentary work and that this physical disability is due entirely to chronic obstructive lung disease. What we have to decide is whether there is evidence in the record from which the Commission could have made findings to support a conclusion that this disease, chronic obstructive lung disease, is an occupational disease. The question now clearly before us for the first time 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. Neither Hansel nor Morrison provide an answer to this question.

It is clear in this case, as it was not clear in Hansel and Morrison, that if plaintiff has an occupational disease at all it is chronic obstructive lung disease. The Commission has found that "plaintiff suffers from chronic obstructive pulmonary disease [with elements] of pulmonary emphysema and chronic bronchitis. . . . Plaintiff is disabled, because of her pulmonary impairment from all but sedentary . . . work . . . ." Dr. Williams diagnosed the condition which he thought physically disabled plaintiff as chronic obstructive lung disease. Dr. Williams testified that claimant's exposure to cotton dust "probably was a cause" of her chronic obstructive lung disease which in turn was the cause of her disability. He also testified as follows:

The patient has definite chronic obstructive pulmonary disease representing a combination of pulmonary emphysema and chronic bronchitis. It is most likely that cigarette smoking and recurrent infection has played prominent roles in her pulmonary impairment. It 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.

Our answer to the question posed is 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.

Significant means "having or likely to have influence or effect: deserving to be considered: important, weighty, notable." Webster's Third New International Dictionary (1971). Significant is to be contrasted with negligible, unimportant, present but not worthy of note, miniscule, or of little moment. The factual inquiry, in other words, should be whether the occupational exposure was such a significant factor in the disease's development that without it the disease would not have developed to such an extent that it caused the physical disability which resulted in claimant's incapacity for work.

This Court in Vause v. Vause Farm Equipment Co., 233 N.C. 88, 63 S.E.2d 173 (1951), recognized that the hazards of employment do not have to be the sole cause of a worker's injury in order for the worker to receive compensation for the full extent of his incapacity for work caused by the injury. Although concluding that there was no causal relationship between the worker's employment and his injury, the Court in Vause said, id. at 92-93, 63 S.E.2d at 176:

The hazards of employment do not have to set in motion the sole causative force of an injury in order to make it compensable. By the weight of authority it is held that where a workman by reason of constitutional infirmities is predisposed to sustain injuries while engaged in labor, nevertheless the leniency and humanity of the law permit him to recover compensation if the physical aspects of the employment contribute in some reasonable degree to bring about or intensify the condition which renders him susceptible to such accident and consequent injury. But in such case `the employment must have some definite, discernible relation to the accident.' [Citation omitted.]

Similarly, it is generally held that where an employee is seized with an epileptic fit . . . and falls due to such . . . causes, even so compensation will be awarded if a particular hazard inherent in the working conditions also contributes to the fall and consequent injury. [Citation omitted.]

. . . .

It appears . . . that the better considered decisions adhere to the rule that where the accident and resultant injury arise out of both the idiopathic condition of the workman and hazards incident to the employment, the employer is liable. But not so where the idiopathic condition is the sole cause of the injury. [Emphasis supplied.]

In Hansel, this Court recognized that Vause stands for the proposition that "the rule of causation is that where the right to recover is based on injury by accident, the employment need not be the sole causative force to render an injury compensable." 304 N.C. at 52, 283 S.E.2d at 106. The Court also noted in Hansel that "[i]t has on occasion been implied that a similar rule of causation should prevail in cases where compensation for occupational disease is sought; however, if a disease is produced by some extrinsic or independent agency, it may not be imputed to the occupation or the employment. Duncan v. Charlotte, 234 N.C. 86, 66 S.E.2d 22 (1951); Moore v. Stevens Co., 47 N.C. App. 744, 748, 269 S.E.2d 159, 162 (1980)." 304 N.C. at 53, 283 S.E.2d at 106. In both Duncan and Moore, as in Vause, there was no causal relation between the disease and the employment.

In Smith v. Fieldcrest Mills, Inc., 224 Va. 24, 294 S.E.2d 805 (1982), claimant Smith, employed as a textile worker for more than thirty-four years and exposed to "large quantities" of cotton dust, was diagnosed as having "severe chronic obstructive pulmonary disease." Medical testimony was that the disease's components were emphysema, chronic bronchitis, and that "chronic byssinosis is a significant component of [Mrs. Smith's] pulmonary problem." Medical testimony showed that byssinosis was "more likely than not [an] etiologic factor in the evolution of chronic bronchitis" and "cigarette smoking may be a relative causative factor." Id. at ___, 294 S.E.2d at 806-07. The Virginia Industrial Commission denied an award on the ground that "it is just as probable that [Mrs. Smith's condition] resulted from a noncompensable cause (smoking) as that it resulted from a compensable cause (cotton dust exposure)." Id. at ___, 294 S.E.2d at 807. The Virginia Supreme Court, in an opinion by Chief Justice Carrico, reversed the Commission and remanded the matter for further proceedings. The Court relied on its earlier case of Bergmann v. L. W. Drywall 222 Va. 30, 278 S.E.2d 801 (1981), in which the worker had suffered a back injury at work. Following this injury the worker was stricken with a non-occupational neurological disorder which, together with the back injury, rendered him incapable of working. The Industrial Commission denied any benefits on the ground that the neurological disorder was just as probable a cause of the incapacity for work as the work-related back injury. The Virginia Supreme Court reversed this ruling, stating that it was not necessary that the work-related injury be the sole cause of the worker's incapacity for work but that full benefits would be allowed when it is shown that "the employment is a contributing factor to the disability." Id. at 32, 278 S.E.2d at 803. In Smith, the lung disease case, the Court said that the same rule should apply. It remanded the matter to the Commission in order for it to determine whether Mrs. Smith's exposure to cotton dust, i.e., her byssinosis, was "a contributing factor" to Mrs. Smith's ultimate disability. 224 Va. at ___, 294 S.E.2d at 808.

Cases from jurisdictions other than Virginia with statutes like ours support our holding here. Newport News Shipbuilding Dry Dock Co. v. Director, 583 F.2d 1273 (4th Cir. 1978), cert. denied, 440 U.S. 915 (1979); Pullman Kellogg v. Workmen's Compensation Appeals Bd., 26 Cal.3d 450, 605 P.2d 422, 161 Cal.Rptr. 783 (1980); McAllister v. Workmen's Compensation Appeals Bd., 69 Cal.2d 408, 445 P.2d 313, 71 Cal.Rptr. 697 (1968); Thornton Chevrolet, Inc. v. Morgan, 148 Ga. App. 711, 252 S.E.2d 178 (1979); Riley v. Avondale Shipyards, 305 So.2d 742 (La.App. 1975); Langlais v. Superior Plating, Inc., 226 N.W.2d 891 (Minn. 1975); Bolger v. Chris Anderson Roofing Co., 112 N.J. Super. 383, 271 A.2d 451 (1970), aff'd 117 N.J. Super. 497, 285 A.2d 228 (1971); Mueller v. State Accident Ins. Fund, 33 Or. App. 31, 575 P.2d 673 (1978). See generally 1B Larson, Workmen's Compensation Law, 41.64 (a)-(c) (1982).

In these cases cigarette smoking together with the inhalation of occupational substances produced either lung disease, see Newport News Shipbuilding, Pullman Kellogg, Thornton Chevrolet, Riley, Langlais and Mueller, or lung cancer, see McAllister and Bolger. The courts concluded in all cases, however, that because there was evidence that inhalation of occupational substances contributed to the diseases, the diseases were compensable occupational diseases. The courts, therefore, either affirmed compensation awards, as they did in Newport News Shipbuilding, Pullman Kellogg, Thornton Chevrolet, Riley, Langlais and Bolger, or reversed denials of awards by administrative agencies, as they did in McAllister and Mueller.

Indeed, the significant contribution principle which we adopt puts upon the claimant in these lung disease cases a somewhat heavier burden than our sister states seem to require or that we require in industrial accident cases. Our purpose in adopting this principle is to strike a fair balance between the worker and the employer in the administration of our Workers' Compensation Act as it is applied to the difficult lung disease cases. To hold that the inhalation of cotton dust must be the sole cause of chronic obstructive lung disease before this disease can be considered occupational establishes too harsh a principle from the standpoint of the worker and the purposes and policies of our Workers' Compensation Act. This Act "should be liberally construed so that the benefits under the Act will not be denied by narrow, technical or strict interpretation." Stevenson v. City of Durham, 281 N.C. 300, 303, 188 S.E.2d 281, 283 (1972). On the other hand, to hold the causation requirement is satisfied if cotton dust exposure contributes to the slightest extent, however miniscule or insignificant, to the etiology of chronic obstructive lung disease, places too heavy a burden on industry. This holding would compromise the valid principle that our Workers' Compensation Act should not be transformed into a general accident and heath insurance law.

In determining whether a claimant's exposure to cotton dust has significantly contributed to, or been a significant causative factor in, chronic obstructive lung disease, the Commission may, of course, consider medical testimony, but its consideration is not limited to such testimony. It may consider other factual circumstances in the case, among which are (1) the extent of the worker's exposure to cotton dust during employment; (2) the extent of other non-work-related, but contributing, exposures and components; and (3) the manner in which the disease developed with reference to the claimant's work history. See Booker v. Duke Medical Center, supra, 297 N.C. at 476, 256 S.E.2d at 200.

In the case before us it is clear that claimant suffers from chronic obstructive lung disease, which prevents her from doing anything but sedentary work. The Commission has so found. There is also evidence that claimant's exposure to cotton dust in her employment "probably was a cause" of her lung disease, that cigarette smoking "was one of the more probable causes . . . after taking into consideration her exposure to cotton dust," and that "emphysema" and "chronic bronchitis" were components of the disease. Further evidence, largely from the claimant herself, detailed her twenty-five years of exposure to cotton dust and the gradual development during those years of her breathing difficulty to the point where it simply rendered her so physically disabled that she could no longer work at the only trade she knew and for which she was qualified. There was also evidence that textile workers, such as claimant here, are "at an increased risk of contracting chronic obstructive pulmonary disease" and that her exposure to cotton dust at Kings Yarn would have aggravated claimant's pulmonary condition existing at the time she went to work there. There was also some evidence that claimant's exposure to cotton dust played an insignificant role in the development of claimant's lung disease. Dr. Williams, as already noted, said: "It 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."

From this evidence the Commission could have found as facts, although it would not have been compelled to find, that: (1) claimant has chronic obstructive lung disease; (2) the two primary causes of this disease are the inhalation of cotton dust for twenty-five years while claimant was a textile worker and the inhalation of cigarette smoke over a similar period of time; (3) the disease also has components of chronic bronchitis and emphysema; (4) the disease developed gradually over the period of claimant's working life until by 1971 claimant had developed a breathing difficulty; (5) by 1977 her breathing difficulty began to affect her ability to do her job because it caused her to be too fatigued to work; (6) by January 1979 claimant's lung disease had rendered her physically unable to work in the textile industry; (7) the disease would not have developed to this extent had it not been for her exposure to cotton dust and her inhalation of cigarette smoke, both of which significantly contributed to, or were significant causative factors in, the development of the disease; (8) because of her age, limited education, and her lifetime of employment in the textile industry, claimant is neither trained nor qualified to do other kinds of work and, at this time, is not able to be gainfully employed; (9) claimant's chronic obstructive lung disease was aggravated to some extent by her exposure to cotton dust at Kings Yarn; and (10) claimant's job in the textile industry exposed her to a greater risk of contracting chronic obstructive lung disease than members of the public generally.

These findings of fact, if made by the Commission, would support the following legal conclusions: (1) claimant's chronic obstructive lung disease is due to causes and conditions characteristic of and peculiar to the textile industry under G.S. 97-53 (13); (2) claimant's chronic obstructive lung disease is not an ordinary disease of life to which the general public not employed in the textile industry is equally exposed under G.S. 97-53 (13); (3) claimant's chronic obstructive lung disease is, therefore, an occupational disease under G.S. 97-53 (13); (4) claimant is totally incapacitated for work under G.S. 97-29, 97-54, and 97-2 (9); (5) claimant's total incapacity for work results from her occupational disease under G.S. 97-52; and (6) claimant's last injurious exposure to the hazards of her occupational disease were in the employment of defendant Kings Yarn under G.S. 97-57. These conclusions of law would, in turn, support an award against defendants and in favor of claimant for workers' compensation benefits for total incapacity for work by reason of an occupational disease.

On the other hand there is some testimony from Dr. Williams which would have supported a finding that claimant's exposure to cotton dust played an insignificant causal role in, or did not significantly contribute to, the development of Ms. Rutledge's lung disease. If the Commission so finds, it would have to conclude that the disease is not an occupational disease in this case.

The Court of Appeals relied on Walston v. Burlington Industries, supra, 304 N.C. 670, 285 S.E.2d 822, amended on rehearing, 305 N.C. 296, 285 S.E.2d 822, for its conclusion that the evidence was insufficient to show claimant had an occupational disease. In Walston the principal medical witness could testify only that claimant's exposure to cotton dust "could possibly have played a role in the causation of his pulmonary problems." Id. at 672, 285 S.E.2d at 827 (emphasis supplied). This Court held, 304 N.C. at 679, 285 S.E.2d at 828:

While smoking `was almost certain[ly] the primary etiologic agent,' there was only a `possibility' that any portion of plaintiff's disability was caused by the inhalation of cotton dust. Such evidence supports the findings and conclusions of the Commission that plaintiff failed to meet his burden of proof, i.e., failed to prove that he had an occupational disease defined in G.S. 97-53 (13). A mere possibility of causation is neither `substantial' nor sufficient.

In the case at bar the medical witness testified claimant's exposure to cotton dust "probably was a cause" (emphasis supplied) of her chronic obstructive lung disease. Therein lies the difference in this case and Walston. See Moore v. Stevens Co., 47 N.C. App. 744, 752, 269 S.E.2d 159, 164, disc. review denied, 301 N.C. 401, 274 S.E.2d 226 (1980) (physician's opinion that "referred to `possibility' rather than `probability'" justified Commission's finding that "plaintiff's chronic pulmonary disease `is not due to her exposure to cotton dust and lint in her employment'"); see also, Lockwood v. McCaskill, 262 N.C. 663, 668-69, 138 S.E.2d 541, 545-46 (1964) ("The `could' or `might' as used by Stansbury [in discussing hypothetical questions propounded to expert witnesses] refers to probability and not mere possibility. . . . If it is not reasonable probable . . . that a particular effect is capable of production by a given cause . . . the evidence is not sufficient to establish prima facie the causal relation . . . ."; the Court stated that testimony showing a particular causal relation is a mere possibility or conjecture should have been excluded).

We conclude that the Court of Appeals correctly determined that the Industrial Commission decided this case under a misapprehension of applicable law and that the Court of Appeals erred in determining that there was no evidence from which the Commission could make findings sufficient to support a conclusion that claimant suffered from an occupational disease. The decision of the Industrial Commission, therefore, is vacated and the case is remanded to the Commission for a new determination of claimant's entitlement to benefits under the legal principles herein set out.

The dissent argues that there is evidence that claimant had other physical ailments unrelated to her pulmonary disease which might have contributed independently of this disease to her incapacity for work. It is true that there was some evidence of these other ailments. The Commission, however, has found that plaintiff's incapacity for work is due entirely to her pulmonary disease. This finding is supported by the evidence and forecloses the argument in the dissent that these other ailments might have contributed to the claimant's incapacity for work. By our remand of the case, therefore, we do not intend to suggest to the Commission that it re-open this aspect of the case. The only question for reconsideration by the Commission is whether the pulmonary disease is an occupational disease when the legal principles set out in this opinion are applied to the facts.

Affirmed in part; reversed in part and remanded.