Firefighters extinguish a blaze at a duplex on Central Avenue. An early morning fire Saturday left two duplex units on Central Avenue uninhabitable, authorities said.The Ocean City Fire Department responded to a call reporting a structure fire on the 4000 block of Central Avenue at 5:20 a.m. There were no injuries reported to any occupants or firefighters, according to a press release.Firefighters arrived within about two minutes to find smoke emanating from the crawl space of a side-by-side, wood-framed dwelling.Fire crews made sure that both units were vacated. One at 4041 Central Ave. was unoccupied, while all occupants of 4043 Central Ave. had evacuated safely on their own.Firefighters located, confined and extinguished a fire in the crawl space and a first-floor bathroom of the 4041 unit.Smoke damage to both units was significant enough that they are uninhabitable. The fire is under investigation.Fire companies from Marmora and Margate provided mutual assistance.