It happened during a fire on Gear Avenue in Lindenhurst around 2:21 a.m.
Firefighters from the East Farmingdale Fire Department were assisted by the Lindenhurst, West Babylon, North Babylon, Babylon, North Lindenhurst, North Amityville, West Islip, South Farmingdale and Farmingdale Fire Departments.
The firefighters all responded and extinguished the fire at Sirob Imports.
A captain of the East Farmingdale Fire Department and two other firefighters were injured when the brick façade collapsed.
Another firefighter was also injured in the fire.
The captain was admitted for a back injury and the others were treated for minor injuries at Good Samaritan Hospital Medical Center in West Islip.
The building sustained severe damage and Arson Squad detectives are investigating to determine the cause of the fire.