The FDNY and EMS received the initial call at 4:42 a.m.
They responded to a two-story attached brick residence located at 23-59 35th Street in Astoria.
The victims were taken to Mount Sinai Hospital in Queens.
One person is in critical condition. The other two were in serious but not life-threatening condition.
The carbon monoxide situation has been mitigated, authorities say.
The cause of the high carbon monoxide levels is not yet known.
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