A 25-year-old construction worker was killed and three others sustained minor injuries Tuesday when a bungalow being expanded into a two-story single-family home collapsed shortly before 11 a.m. in Gerritsen Beach, Brooklyn.

An emergency order to demolish the remaining structure at 40 Frank Court and to temporarily evacuate the building next door at 38 Frank Court as a precaution were issued by the city Buildings Department Tuesday afternoon.

All proper permits had been filed for the project, which was an enlargement of the building both vertically and horizontally, said Buildings Department spokeswoman Ryan FitzGibbon.

"We're looking into the on-site design" and other factors that might have caused the cave in, she said.

Although the investigation is ongoing, FitzGibbon said the collapse apparently occurred because of inadequate anchoring of the second story to the existing structure, which was itself in very poor condition.

Workers were setting up and climbing ladders to the roof when the implosion occurred, she said.

About 50 firefighters from eight units responded to the collapse, which occurred near the intersection of Seba Avenue.

amNewYork

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Penn Station renovations ... Target recalls baby wipes ... LI Catholic group's challenge to diocese Credit: Newsday

Updated 59 minutes ago 18 repeat retail shoplifters charged ... Penn Station renovations ... Hochul: $146M to repair LI roads, bridges ... Out East: Jamesport Country Store

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