Appeal from a decision of the Workers’ Compensation Board, filed November 3, 1978. Claimant sustained an original injury to his leg and back on November 27, 1972. Thereafter, on December 8, 1974 and June 27, 1975, he suffered further mishaps, alleging on each occasion that "his leg gave out”, causing the subsequent injury. The issue of apportionment of liability among carriers is resolved by determining whether the subsequent injuries were the product of new and separate accidents or were consequential to the original accident of November 27, 1972. Here, the record is replete with conflicting medical evidence provided by experts in their respective fields. The board elected to accept the testimony which concluded that the second and third accidents were due to the injury sustained in the first incident. Since this determination is based upon substantial evidence, it may not be disturbed (Matter of De Maio v Rockford Plumbing & Heating, 63 AD2d 1041; Matter *661of Ford v Sidnam Concrete, 38 AD2d 984). Decision affirmed, with costs to the Insurance Company of North America against the employer and its insurance carrier. Sweeney, J. P., Kane, Staley, Jr., Main and Herlihy, JJ., concur.