SANTA ROSA (CBS SF) – A woman was transported to a hospital and five others displaced following a two-alarm fire at a near-century-old, six-story apartment building in downtown Santa Rosa early Wednesday morning, according to fire officials.

The blaze, first reported at 12:47 a.m. per dispatch, started in a single unit on the sixth floor of the Rosenberg Building at 306 Mendocino Avenue. Assistant Fire Marshal Paul Lowenthal said it was under control at 1:10 a.m. The resident of the unit where the blaze started was the sole person taken to a hospital for treatment of smoke inhalation.

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According to Lowenthal, the building was constructed in the early 1900s and is one of a few buildings in the city that require a special, increased response from the fire department due to its age and number of residents inside. The City of Santa Rosa’s website says the structure is a historic landmark with all single-bedroom, single-occupancy residences.

Lowenthal credited the building sprinkler system with keeping the fire to the single-unit, but said units throughout the sixth floor had smoke and water damage and some on the fifth floor had water damage, as well.

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The American Red Cross is assisting the five residents displaced on the fifth and sixth floors.

Mendocino Avenue remains closed between Fourth and Fifth Streets, and Fourth Street is also closed. Lowenthal estimated both streets will be closed into in the early morning as crews investigate the fire and overhaul the scene.

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