Officials confirm that one firefighter has died and another is in serious condition after a three-alarm warehouse fire in Bushwick.

Mayor Michael Bloomberg confirmed that the firefighter who died was 47-year-old Lt. Richard A. Nappi, of Engine Company 237. Bloomberg said that Nappi, a 17-year veteran of the FDNY, died of an apparent heart attack.

Officials say four other firefighters suffered minor injuries.

Firefighters say the fire started when some cardboard boxes ignited at around 1 p.m. in a warehouse at 930 Flushing Ave. Officials say the fire was brought under control at around 4 p.m.

Nappi, who lived in Suffolk County, leaves behind a wife and two children.

Mayor, FDNY commissioner gather at hospital where Lt. Nappi died