ARLINGTON HEIGHTS, Ill. — One person was critically injured in a fire at an apartment complex in Arlington Heights.

Fire crews responded around 11:55 p.m. Wednesday to the multi-family residence located at 2315 East Olive Street, just off Rand Road. Upon arrival, crews discovered a fully involved unit on the first-floor.

Firefighters removed a resident from the fire unit and he was transported to an area hospital with life-threatening injuries.

Residents in 48 units have been displaced due to the fire.

Approximately 30 firefighters from six surrounding departments responded to the scene.

The cause of the fire is still under investigation with assistance from the State Fire Marshal’s office and the Arlington Heights Police Department.