OPINION
This appeal is from the affirmance by the superior court of an Alaska Workers’ Compensation Board (Board) decision denying benefits to Paul Grainger (Grainger). Grainger sought benefits following a heart attack that had its onset while Grainger was on the job. He claims that job stress either caused or aggravated a pre-existing condition that caused the heart attack.
We REVERSE and REMAND the case to the superior court with instructions to remand it to the Board for reconsideration in light of our decisions in Wade v. Anchorage School District, 741 P.2d 634 (Alaska 1987), and Fox v. Alascom, 718 P.2d 977 (Alaska 1986). The Board may take such additional evidence it deems necessary for a proper resolution of the issues raised.1
1.
In response to the dissent, we observe the following. Employment is a legal cause in a disability if it is a “substantial factor” in bringing about the harm. Ketchikan Gateway Borough v. Saling, 604 P.2d 590, 597-98 (Alaska 1979). Dr. Stewart did not testify that job related stress was or was not a "substantial factor” in bringing about the final result. Dr. Stewart’s testimony was that there was insufficient evidence or documentation in his records regarding environmental or physical or emotional stress:
Q. You have no information one way or the other; is that correct?
A. Yes, that is correct.
Second, although the dissent describes Dr. Stewart as one who the Board could regard as