Where the area of special flood hazard or shaded X-Zone, as established in appendix G of the New York city building code, is modified on or after the effective date of this section, any building whose main use or dominant occupancy is group I-2 hospital and that is newly identified as being within such modified area of special flood hazard or shaded X-Zone shall, no later than 20 years following the adoption of such modification, comply with the retroactive requirements of section G311.3 of appendix G of the New York city building code. The owner of such building shall, no later than 20 years following the adoption of such modification, file with the department a report detailing compliance with such requirements in accordance with section G311.3.2.