In Rosenberg v. Equitable Life Assur. Socy. of U.S. (79 NY2d 663, 668, 595 NE2d 840, 584 NYS2d 765 [1992]), the Court enumerated the exceptions somewhat differently, encompassing those circumstances "where the employer: (1) is under a statutory duty to perform or control the work; (2) has assumed a specific duty by contract; (3) is under a duty to keep premises safe; (4) has assigned work to an independent contractor which the employer knows or has reason to know involves special dangers inherent in the work or dangers which should have been anticipated by the employer."