Officers responded to a 911 call of a carbon monoxide alarm at the Bay Shore residence on Lincoln Boulevard at 12:10 p.m. Saturday, Dec. 19.
Carbon monoxide detectors alerted first responders to high levels of the gas in the basement and first floors of the home, Suffolk County Police said.
It was later determined a furnace vent was not functioning correctly, sending carbon monoxide into the residence, according to police.
The residents -- an adult woman and her nine children -- evacuated prior to police arrival.
While outside of the house, three of the children, a 4-year-old girl, a 6-year-old boy, and a 10-year-old girl, began exhibiting signs of carbon monoxide poisoning, said police.
They were treated on the scene and transported via Brentwood Legion Ambulance to Good Samaritan Hospital Medical Center in West Islip.
The other six children, who ranged in age from 18 months to 15 years old, and their mother, were evaluated on the scene and not injured.
The Brentwood Fire Department and Fire Marshal also responded.
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