Two acres of city property along the East River have serious structural damage, a city comptroller audit revealed Tuesday. The city has leased the site out since 1959, most recently to New York Skyports, which uses the site as a marina, gas station, and parking garage. The damage includes corroded piers, water penetration and a parking garage that risks “catastrophic failure.” “The Economic Development Corporation’s inadequate oversight of this lease may have jeopardized public safety, placed the city at financial risk, and may cost the city upwards of $5.5 million or more to rectify conditions dangerous to the public,” Comptroller William Thompson Jr. said.