Queens, NY – One person was found dead after a carbon monoxide leak inside a Queens apartment building forced an evacuation, officials said.

The FDNY responded to the scene on Leavitt Street in Flushing around 8 p.m. Tuesday, officials said, after a report of someone in cardiac arrest. Once inside the building, EMS said found a woman unconscious on the floor of her apartment. She was rushed to Flushing Hospital, where she was pronounced dead.

First responders discovered high carbon monoxide levels in the apartment where she was found and throughout the building, EMS said. Other residents of the building were evacuated, and doors and windows for the six-story building were left open in order to ventilate it.

One resident said firefighters told him it was a gas leak as he was evacuating. The Department of Buildings said that investigators with their boiler unit were at the scene. A cause has not year been determined.

The name and age of the woman who died have not yet been released, as police were looking to contact her family.