In this case, the Third Circuit was asked to determine whether the design and accessibility requirements of the Fair Housing Act (FHA) apply to commercial buildings constructed prior to March 1991—the effective date of the requirements—but converted to residential use after that date. In affirming the lower court’s dismissal, the Third Circuit found that the U.S. Department of Housing and Urban Development’s (HUD) interpretation that the FHA requirements only apply to buildings constructed after March 1991 was reasonable.