dissenting.
Even if claimant’s idiopathic condition, in comparison with the workplace condition, would be considered the major factor in her resulting carpal tunnel syndrome, it seems to me that her workplace activities were the major contributing cause, as contemplated in former ORS 656.802(l)(a). Only if non-work conditions, other than idiopathic propensities, outweigh workplace conditions can we say that the workplace conditions did not constitute a major contributing cause of her disease. The referee and the Board did not err in comparing only activities on and off the job to decide whether the workplace activities were the major contributing cause of claimant’s carpal tunnel syndrome.
The majority appears to conclude that idiopathic conditions can be non-work conditions to which a claimant is ordinarily subjected or exposed. That conclusion is contrary to the statutory definition of occupational disease, which uses language that contemplates external causative forces, and to the spirit of the Workers’ Compensation Law.
For this case, an occupational disease is:
“Any disease or infection which arises out of and in the scope of the employment, and to which an employe is not ordinarily subjected or exposed other than during a period of regular actual employment therein.” Former ORS 656.802(1)(a).
To prove an occupational disease, a claimant first must show that the disease “arises out of and in the scope of the employment.” We have previously compared that language to similar language in the definition of “compensable injury” in ORS *571656.005(7)(a) and determined that the unitary work-connection analysis for compensable injuries also applies to occupational diseases. SAIF v. Noffsinger, 80 Or App 640, 645, 723 P2d 358, rev den 302 Or 342 (1986). “If the relationship between the disease and the employment is sufficient, then the disease arises out of and in the scope of employment.” 80 Or App at 645. When a compensable injury is involved, work-connection is established if the work activity is a material contributing cause of the injury.
However, under former ORS 656.802(1)(a), a second requirement must be satisfied to prove an occupational disease. A claimant must also prove that the disease is one “to which an employe is not ordinarily subjected or exposed other than during a period of regular actual employment therein.” In other words, a claimant also must prove that work conditions or exposures, when compared with non-work conditions or exposures, were a major contributing cause of the disease. Dethlefs v. Hyster Co., 295 Or 298, 310, 667 P2d 487 (1983); SAIF v. Noffsinger, supra, 80 Or App at 645-46. The language of the second requirement — that an employe not be subjected or exposed — contemplates external forces that cause the disease, not internal forces peculiar to the individual. Once work-connection is proved, on the job conditions and exposures must be compared with off the job conditions and exposures to determine the major contributing cause. That is what the referee and the Board correctly did.
The referee and the Board also correctly stated well-settled principles that the employer takes the worker as it finds her and that the Workers’ Compensation Act is to be liberally construed in favor of injured workers. Under those principles, an employer is liable for disability, even if the worker has a preexisting condition, if the workplace injury contributes to the disability. The Workers’ Compensation Law “prescribes no standard of physical fitness to which the employee must conform, and compensation is not based on any implied warranty of perfect health.” Keefer v. State Ind. Acc. Commission, 171 Or 405, 412, 135 P2d 806 (1943).1 The *572majority’s conclusion that idiopathic conditions múst be taken into consideration in determining the major contributing cause effectively eliminates that principle in the occupational disease context. Workers whose idiopathic conditions, such as age and sex, may render them more vulnerable to work conditions that cause disease will be at a great disadvantage in showing persuasively that work conditions or exposures were a more important causative factor than the idiopathic conditions. The majority, in effect, is requiring a warranty of health, and that is not required under the Workers’ Compensation Law.
For these reasons, the majority is wrong, and I dissent.
The court in Keefer also noted that “[t]he great weight of authority is to the effect that the existence of a * * * disease which does not impair the employee’s ability to work will not prevent his recovery of compensation if an accident accelerates the disease to a degree of disability!.]” 171 Or at 412. That should also be true when work conditions or exposures accelerate a disease to a disability.