dissenting.
I respectfully disagree with the court and would vacate the Appellate Division’s decision.
The issue presented in this case is one of first impression for this court. The court must concede that the Workers’ Compensation Act does not address the applicability of apportionment for an employee’s incapacity caused by a work-related injury and a subsequent non-work-related injury. See 39 M.R.S.A. § 51 (Supp.1988) (entitlement for compensation for injuries arising out of and in the course of employee’s employment). The court’s reliance on Richardson v. Robbins Lumber, Inc., 379 A.2d 380 (Me.1977), as controlling precedent is misplaced. As the court notes, we held in Richardson that “the proper approach to the causation question requires that the commissioner first determine whether a work-related injury occurred. If that inquiry is answered in the affirmative, the critical question then becomes whether the work-related injury remained a substantial factor in causing the ultimate disability.” Id. at 383 (citation omitted) (emphasis added). In Smith v. Dexter Oil Co., 408 A.2d 1014, 1015-16 & n. 2 (Me.1979), we further clarified the term “substantial” as meaning a real or actual cause. In neither case was the issue presented, nor did we determine the extent of the liability of an employer for the incapacity of an employee resulting from a work-related and subsequent non-work-related injury.
Accordingly, the court today holds for the first time that when a work-related injury is a cause of an employee’s incapacity to work which only occurs after the employee has suffered a later non-work-related injury or injuries, the employer is liable for the entire incapacity suffered by the employee. Under the court’s decision, an employer would be responsible for an employee’s total incapacity even though a work-related injury caused one percent or less of the incapacity and a subsequent non-work-related injury caused ninety-nine percent or more of the incapacity. Nothing in the Workers’ Compensation Act indicates that the Legislature intended that employers be general disability insurers for non-work-related injuries suffered by an employee. See 39 M.R.S.A. § 51 (Supp. 1988); id. § 94-A(3) (Workers’ Compensation Act should be construed “to ensure the efficient delivery of compensation to injured workers at a reasonable cost to employers” and not in favor of employee or employer).
After January 15, 1979 and until he suffered two non-work-related back injuries six and one-half years after his work-related injury in 1978, Brackett had continued at the same job without missing any work. *779I believe that an apportionment of the incapacity caused by the non-work-related injury and the work-related injury is fair both to the employee and employer and is consistent with the compensation scheme set forth by the Legislature. See 39 M.R.S.A. §§ 51, 94-A. Apportionment is not a new concept to the Commission. See id. § 104-B (apportionment of liability among responsible insurers for multiple injuries). An employer should be liable for the entire incapacity only when the incapacity cannot be apportioned with reasonable medical certainty between the work-related injury and the subsequent non-work-related injury. Accordingly, I would vacate the decision of the Appellate Division with instructions to remand to the Commissioner for an apportionment based on the loss of earning capacity caused by the work-related and the successive non-work-related injuries.