Claimant seeks review of an order of the Workers’ Compensation Board (Board) affirming employer’s denial of his claim. He argues that the Board erred in its treatment of his out-of-state employment with employer. We reverse and remand for reconsideration.
Claimant began experiencing back pain in 1988 while working for employer Larch Enterprises (Larch) in California. At that time, Larch was not an Oregon employer. Claimant sought treatment from a chiropractor but he never missed work. Larch told claimant to seek coverage under his health insurance and discouraged him from filing a claim for workers’ compensation benefits in California. In October, 1990, Larch moved its operations to Oregon and became an Oregon employer. In late December, claimant began experiencing severe back pain, but continued to work. In early February, 1991, Larch fired claimant.
Claimant went to see Dr. Driver about his back condition, and x-rays revealed a degenerative disc disease. Driver stated in his report that
“[claimant’s] work activities beginning in 1988 were the cause of his back condition. The degeneration is due to continuous work, not necessarily one specific injury.”
Claimant filed a workers’ compensation claim in Oregon for “lower back pain.” SAIF, Larch’s Oregon workers’ compensation insurer, denied the claim, and claimant requested a hearing. The Board determined that Larch was not a subject employer when its operations were in California and that claimant was not a worker subject to Oregon law while employed in California. Therefore, the Board concluded, “any injuries suffered during claimant’s employment in California are not compensable” and claimant must prove that his employment in Oregon was the major contributing cause of his disease.1
*300Claimant assigns error to the Board’s treatment of his out-of-state employment. He argues that the last injurious exposure rule relieves him of the burden of proving that any specific employment or exposure caused his disease.
In order to establish an occupational disease, claimant must show that his condition arose “out of and in the course of employment” and was “caused by substances or activities to which [he was] not ordinarily subjected or exposed other than during a period of regular actual employment * * *.” ORS 656.802(1). He must show that the major contributing cause of his disease was work related. Runft v. SAIF, 303 Or 493, 498, 739 P2d 12 (1987). When a claimant asserts that work conditions at a single employer are the cause of the disease, the claimant’s task is relatively straightforward: ‘ ‘the claimant must show that working conditions at that employment were the major contributing cause of the disease.” 303 Or at 498-99. However, when there are two or more employers or insurers, the task becomes more difficult. As the Supreme Court recognized, “by their very nature[,] chronic conditions * * * usually cannot be traced to a single incident or injury.” Inkley v. Forest Fiber Products Co., 288 Or 337, 341, 605 P2d 1175 (1980).
To relieve claimants of ‘ ‘the often impossible burden of showing that workplace conditions at a specific time and place caused” an occupational disease, the courts adopted the last injurious exposure rule. 288 Or at 344. This “rule of proof’ aspect of the last injurious exposure rule2
“operates generally for the benefit of claimants. It relieves *301claimants of the burden of proving the degree to which, if any, exposure to disease causing substances at a particular employer actually caused the disease. The claimant is required to prove only that the disease was caused by employment-related exposure; the claimant is not required to prove that exposure at a particular employer’s workplace caused the disease. Whether employment at any one workplace was the actual cause of the disease is irrelevant under the rule.” Runft v. SAIF, supra, 303 Or at 500. (Citations omitted.)
The rule operates in the context of claims implicating multiple employments or multiple insurers for the same employer. FMC Corp. v. Liberty Mutual Ins. Co., 73 Or App 223, 698 P2d 551, rev den 299 Or 203 (1985); Meyer v. SAIF, 71 Or App 371, 373 n 1, 692 P2d 656 (1984), rev den 299 Or 203 (1985).
Here, claimant’s out-of-state employment, if relevant at all for purposes of determining compensability, would be treated as a separate occupational exposure from his Oregon exposure, because employer had a different workers’ compensation insurer during that time. The question is whether claimant’s out-of-state employment can be considered to prove that his condition was caused by his employment.
In Bennett v. Liberty Northwest Ins. Corp., 128 Or App 71, 875 P2d 1176 (1994), the claimant suffered from tinnitus and hearing loss. He had worked at two different employers, both of which had conditions that could have caused his disease. The claimant entered into a disputed claim settlement with the first employer. In litigation involving only the second employer, he attempted to use the last injurious exposure rule to establish the compensability of his disease. The Board concluded that, because the claimant had settled with the first employer, he had elected to prove actual causation against the second employer. We reversed the Board and held that, in determining whether a disease is work related, the rule of proof aspect of the last injurious exposure rule allows consideration of all employments, even those that could not ultimately be held responsible for the claim. 128 Or App at 78; see also Kepford v. Weyerhauser Co., 77 Or App 363, 713 P2d 625, rev den 300 Or 722 (1986).
*302Citing Progress Quarries v. Vaandering, 80 Or App 160, 722 P2d 19 (1986), SAIF argues that all out-of-state employments must be disregarded for purposes of determining whether the last injurious exposure rule is even applicable. For example, it argues that if, as here, a claimant has only two employments, one of which was out-of-state, then the out-of-state employment must be disregarded. Therefore, according to SAIF, because only one potentially responsible employer remains, the last injurious exposure rule is inapplicable and the claimant must show actual causation by the Oregon employer. We disagree.
In Progress Quarries, all of the parties agreed that the claimant’s disease, which could have been caused by any or all of the employers, was compensable; the issue was the assignment of responsibility. One Oregon employer sought to establish that a subsequent out-of-state employer was responsible for the claim, because conditions at that out-of-state workplace were of the kind that could have caused the disease. We held that, under the last injurious exposure rule, when it has been shown that the Oregon employment is injurious and a potential cause of the claimant’s occupational disease, the claimant is entitled to compensation in Oregon. We held that an Oregon employer cannot proffer as a defense a subsequent potentially causal employment not covered by the Oregon Workers’ Compensation Act. 80 Or App at 164-66.
The issue is different here, but the objective is the same: compensation for a work-related condition, a potential cause of which is an Oregon employment. The consideration of claimant’s out-of-state employment for the purpose of determining whether his condition is work related does not necessarily bear on which employer might ultimately be held responsible for the claim. Although permitting a claimant to rely on out-of-state employment to establish a work relationship might increase the chances that a claim will be found to be work related, it does not alter the requirement set out in Progress Quarries and the cases it cites, that, for the Oregon employer to be held responsible, the Oregon employment must be injurious and a potential cause of the disease. We hold that for purposes of establishing that an occupational *303disease is work related, a claimant may rely on all employments, even those that are not subject to Oregon’s workers’ compensation laws.
SAIF argues that to adopt such a rule would make Oregon “the workers’ compensation dumping ground for the United States,” permitting a claimant with even the briefest period of employment in Oregon to receive compensation in Oregon for a condition that was caused elsewhere. SAIF suggests that, to avoid those consequences, we should require a claimant to establish that recovery is precluded in the other jurisdictions where there was potentially causative employment. We have done that in cases involving an initial compensable injury in Oregon and a subsequent out-of-state increased disability of the same part of the body. See Wootten v. Stadeli Pump & Construction, 108 Or App 548, 816 P2d 689 (1991); Olson v. EBI Co., 78 Or App 261, 715 P2d 1348 (1986); Miville v. SAIF, 76 Or App 603, 710 P2d 159 (1985). However, we rejected that same requirement in the occupational disease context in Progress Quarries v. Vaandering, supra, 80 Or App at 166, where we said that cases involving successive injuries
“do not involve the problems of proof and responsibility which produced the disease-oriented last injurious exposure rule, under which issues are whether there is compensability in the first instance and which of the successive employers or carriers is responsible.”
Accordingly, we held that, in occupational disease cases, the claimant is not required to file a claim with other potentially causative out-of-state employers in order to receive compensation in Oregon. 80 Or App at 166.3 The same reasoning applies here.
Because of our disposition of claimant’s first assignment of error, we need not reach claimant’s second.
Reversed and remanded for reconsideration.
On June 27, 1994, during the pendency of this review, SAIF accepted a “symptomatic exacerbation of a degenerative disc disease in the lower back.” SAIF has filed a motion to dismiss, contending that that acceptance renders moot claimant’s petition; the acceptance covers all the compensation requested by claimant to this point. However, we are asked to review the Board’s determination that claimant has not shown a compensable “degenerative back condition.” The claim is broad enough to encompass that condition. SAIF’s acceptance of the symptomatic *300exacerbation does not render moot the question of whether the underlying degenerative back condition is compensable.
The last injurious exposure rule also operates to assign responsibility:
“As a rule of assignment of responsibility, the last injurious exposure rule assigns full responsibility to the last employer at which the claimant could have been exposed to the disease-causing substance. This is true no matter how brief or insignificant the possible exposure at the last such employer.” Runft v. SAIF, supra, 303 Or at 500.
The 1990 amendments to the Workers’ Compensation Law did away with some aspects of the last injurious exposure rule. See SAIF v. Drews, 318 Or 1, 6-9, 860 P2d 254 (1993); Liberty Northwest Ins. Corp. v. Senters, 119 Or App 314, 850 P2d 403 (1993). But the amendments had no effect on the last injurious exposure rule’s role in initially assigning responsibility for an occupational disease. SAIF v. Yokum, 132 Or App 18, 887 P2d 380 (1994).
SAIF also argues that this rule would create situations in which a worker could obtain a double recovery and that there is a policy in the Oregon workers’ compensation system against double recoveries. While we acknowledge that double recovery is a potential problem, the alternative is to leave an Oregon worker with an admittedly work-related disease without compensation. We believe that the policy to make certain that Oregon workers are compensated for their injuries, see ORS 656.012, outweighs the concern about double recovery.