The fire broke out after 2 p.m. Sunday at the Golden Living Center on Chapin Street.
Officials say lightning may have caused the fire which started in the attic of the building.
The 41 residents all got out and were taken to a shelter at Florence Elementary School. Most of them are still there; however, some families brought their loved ones home.
No one was injured.
Officials say about 30 percent of the building has interior structural damage.