WILLIAMSBURG, BROOKLYN — Developers are building thousands of homes along Brooklyn's coastline where dangerous floods are most likely to strike, despite a new study has found.

More than 3,500 new apartments have been built in flood-prone parts of Williamsburg and Greenpoint since Hurricane Sandy struck New York City in 2012, according to the real estate site Localize.city. Development has since boomed in the area, with more than 3,590 units going up in northern Brooklyn and almost 2,000 in Long Island City, despite federal data that shows these neighborhoods are most likely to flood.

"At least one out of every eight new units expected to open in New York City over the next four years will sit in a serious flood zone," Localize.city data scientist Idan Richman said. "Ninety-seven percent of the new buildings under construction in the floodplain are in areas that were inundated during Sandy." Analysts also noted, "In terms of sheer numbers of new units, three waterfront neighborhoods — Long Island City, Williamsburg and Greenpoint — have the lion's share."

These findings were part of citywide analysis that found 12 percent of New York apartments that have either gone up in the past five years, or are in the process of going up now, are in city flood zones. Localize.city discovered 21,450 new units in areas deemed risky by FEMA in its 2015 Preliminary Flood Insurance Rate Map, and that almost half of new units will be situated in Williamsburg, Greenpoint and Long Island City.

Researchers also found a record-breaking number of new buildings popping up in the floodplains of Brighton Beach, Gravesend and Coney Island — neighborhoods that were reportedly shell-shocked by the superstorm's destruction — and where 45 new residential projects are currently underway.

The city has been working to better protect nearly 70,000 buildings that sit in local flood zones since Hurricane Sandy first ransacked New York — killing 43 people, leaving two million without power and destroying 800 buildings — but work on many of those projects had yet to commence in 2017, five years after the storm hit.

And while work is underway to protect public housing and schools against future storms, few of those city-run resiliency projects are happening on the Williamsburg and Greenpoint waterfront, leaving developers to handle the city's updated building codes themselves. "Buyers and renters should be aware of both the immediate and long-term outlook for how their home and neighborhood could be affected," said urban planner Olivia Jovine said.