The fire broke out around 1:35 a.m. on the second floor of a building on Eastern Parkway.
Two women, ages 24 and 26, were taken to Kings County Hospital in critical condition.
A 55-year-old woman was listed in stable condition at Staten Island University Hospital.
Two other residents were also treated for injuries, but are expected to recover.
The Red Cross responded, offering support to families forced from their homes.
The cause of the fire is under investigation.
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