A low-rise apartment building in North York was evacuated on Thursday due to high levels of carbon monoxide, and one person was sent to the hospital.Toronto Fire Services (TFS) tells CityNews that crews were called to 3018 Keele Street near Downsview Park Boulevard just after 4 a.m. on Thursday.First responders detected high levels of carbon monoxide, resulting in the complete evacuation of the low-rise building.Toronto paramedics tell CityNews that one person was transported to a hospital. Their condition is unknown. Others from the building have been assessed at the scene.A mechanical issue in the building is believed to have caused the carbon monoxide to spread, with early indications pointing to the basement boiler room as the source.Enbridge Gas is at the scene as crews ventilate the building.