A fire reported shortly after 5 p.m. on Friday appears to have extensively damaged the Sault's historic Steam Baths building on Albert Street.
Fire crews attended and extinguished the flames but the interior is heavily coated in smoke and soot.
The building appeared to be unoccupied at the time of the fire.
Albert Street was closed between Huron and Toronto streets while firefighters extinguished the fire.
SooToday will have more on this when information becomes available.