A carbon monoxide leak forced the evacuation of a catering hall in Great Neck Saturday.Ann Dockery, of Deer Park, was one of 600 people in attendance at the Irish dinner dance at Leonard?s of Great Neck. Dockery said she began to feel dizzy and noticed people around her collapsing. When police and fire fighters arrived they informed the attendees that they had been exposed to carbon monoxide. Fire officials from the Manhasset-Lakeville Fire Department confirm that detectors registered high levels of carbon monoxide due to a faulty boiler. Seventeen people were taken to North Shore University Hospital. Four others, including Dockery's husband, were taken to Jacobi Medical Center in the Bronx where they are being treated in a hyperbaric chamber. A spokesperson for Leonard?s of Great Neck issued a statement, which read in part, ?It has been determined that an accidental blockage of an air intake vent was the cause of this unfortunate circumstance. We offer our most sincere apologies to those who were affected."