Opinion ID: 884122
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Heading Rank: 1

Heading: Appropriate Standard of Causation

Text: The Occupational Disease Act of Montana (the Act) is codified at Title 39, Ch. 72, MCA. To qualify for benefits under the Act, the claimant must prove that his or her employment is a proximate cause of the claimant's condition. Under § 39-72-408, MCA: Occupational diseases shall be deemed to arise out of the employment only if: (1) there is a direct causal connection between the conditions under which the work is performed and the occupational disease; (2) the disease can be seen to have followed as a natural incident of the work as a result of the exposure occasioned by the nature of the employment; (3) the disease can be fairly traced to the employment as the proximate cause; (4) the disease does not come from a hazard to which workmen would have been equally exposed outside of the employment; (5) the disease is incidental to the character of the business and not independent of the relation of employer and employee. Polk recognizes that to prevail, he must prove that his lung condition was proximately caused by his exposure to dust and other irritants at Koch. However, he asserts that the hearings examiner and the four doctors who concluded that he did not suffer from an occupational disease applied the wrong standard of causation. Under Montana law, a worker may receive pro rata compensation [i]f an occupational disease is aggravated by any other disease or infirmity not itself compensable or if disability or death from any other cause not itself compensable is aggravated, prolonged, acceleraed, or in any way contributed to by an occupational disease. Section 39-72-706(1), MCA (emphasis added). `Occupational disease' means harm, damage, or death ... arising out of or contracted in the course and scope of employment and caused by events occurring on more than a single day or work shift. Section 39-72-102(10), MCA (emphasis added). Polk argues that in light of these statutes and our case law construing them, he must only show that a work-related exposure aggravated or contributed to his illness. He asserts that the testimony of several of the doctors, and in turn the conclusion of the hearings examiner, was based on the misconception that to satisfy causation, Polk had to prove that the occupational exposures were the major factor causing his health problems. Indeed, this Court has held that an employer accepts his employee with all of his injuries and diseases and, thus, that the test for compensability is whether the job-related incident significantly aggravated the preexisting condition. Ridenour v. Equity Supply Co. (1983), 204 Mont. 473, 665 P.2d 783; see also Eastman v. Atlantic Richfield Co. (1989), 237 Mont. 332, 777 P.2d 862. For example, in Ridenour, 665 P.2d at 784, the claimant was a long-term smoker who worked in a dusty grain-processing plant. After an incident of grain inhalation, the claimant developed a cardiopulmonary disease. Ridenour, 665 P.2d at 784. This Court held that diseases are subject to aggravation and acceleration and that the grain inhalation had aggravated the claimant's preexisting lung disease. Ridenour, 665 P.2d at 788. Thus, we found that he was entitled to pro rata compensation. Ridenour, 665 P.2d at 788. Planet argues that the aggravation statute does not relieve the claimant of the burden of proving proximate cause, but that Polk is still required to prove a direct causal connection between the work-related factors and his resulting condition. We agree with Planet that the aggravation statute, § 39-72-706, MCA, does not circumvent the proximate cause requirement of § 39-72-408, MCA. However, Planet contends that to prove proximate cause, Polk must show that occupational exposures were a substantial contributing factor to his health problem. In light of the proximate cause statute and the aggravation statute, we agree with the Workers' Compensation Court that occupational aggravations of preexisting nonoccupational diseases are compensable, as are occupational diseases which are aggravated by non-occupational factors. As we held in Ridenour, the test for compensability under the Act is whether occupational factors significantly aggravated a preexisting condition, not whether occupational factors played the major or most significant role in causing the claimant's resulting disease. Other jurisdictions, such as New Mexico, have come to the same conclusion when considering the effect of numerous factors, occupational and non-occupational, on pulmonary diseases: These cases have dealt specifically with the analytical and testimonial difficulties inherent in determining compensability of diseases caused by the combined effect of smoking and work-related exposures to dust, asbestos, radiation, and various toxic fumes.... The majority rule in states with a statutory scheme similar to New Mexico's allows compensation without a showing that work-related exposures were the predominant cause of the disease or death. Buchanan v. Kerr-McGee Corp. (N.M.App. 1995), 121 N.M. 12, 908 P.2d 242, 249. That court noted that [t]he work-related cause may, in fact, be a minor factor so long as the worker establishes that, as a matter of medical probability, it was a cause of the disability. Buchanan, 908 P.2d at 249. Therefore, we hold that Polk need not prove that occupational exposures were the major or substantial factor causing his chronic pulmonary condition. Rather, Polk must prove that he is suffering from a disease that is proximately caused by his employment or that exposure to dust and other irritants while in the course of his employment at Koch contributed to or aggravated a preexisting condition. Having stated the appropriate test for causation, we proceed to apply it to this case.