Karen O'Callaghan, who began her 27-year career in law enforcement as a patrol officer, has broken new ground to become chief of department - and the highest-ranking woman to serve in the 84-year history of the Nassau County Police Department. O'Callaghan, 54, will report directly to the commissioner and oversee the chiefs of the department's patrol, detective and support divisions. Hers is the most senior promotion in a wave of about 130 promotions, including civilians, to be recognized Thursday in a ceremony at Kellenberg Memorial High School in Uniondale. The promotions, effective June 19, mark the ascension of many sworn officers who are women, and racial and ethnic minorities. The promotions are also historic in installing Det. Lorna Atmore, 47, to captain. That's the highest position ever held by a black woman. "Historically, this is a big day for us," said Commissioner Lawrence Mulvey. "We have advanced the careers of women more significantly than we have before. They are all in position to go into key management spots." Also promoted was Keechant Sewell, the second black woman to become lieutenant. The appointments pleased NYPD Deputy Inspector Corey Pegues, president of the local chapter of the National Organization of Black Law Enforcement Executives, who said the promotions signal real change in a force that has long been almost exclusively white and male. "Commissioner Mulvey's heart is in the right place," said Pegues, commanding officer of the 67th Precinct in Brooklyn. "He's trying to really do something with diversity." Mulvey said the promotions come as the department's ranks shrink because of recent retirements, opening up many senior posts. "Although many of them were experienced, talented and dedicated leaders that will be missed, their replacements are equally competent and thoroughly experienced in all aspects of the police department," said County Executive Thomas Suozzi. O'Callaghan's previous assignments include commanding officer of several units: the Homeland Security and Counter Terrorism Bureau, various patrol Precincts, the police Academy, the Personnel and Accounting Bureau, and the Second Precinct Detective Squad. Robert Turk, a 36-year veteran, was named chief of patrol. His previous assignments include commanding the Bureau of Special Operations, Mounted Unit and the Third Precinct. He also was deputy commanding officer of the Seventh Precinct and was the county gang czar. Steven Skrynecki, a 34-year veteran, is now chief of detectives. He has served as commanding officer for units including Vehicle Theft Squad, Robbery Squad, Second Precinct Detective Squad, Narcotics/Vice Squad, the Second Precinct and Internal Affairs. Kevin Lowry, a 27-year veteran, is now chief of support. His past assignments include deputy chief of support, chief of probation, Nassau County Criminal Justice coordinator, and commanding officer of the Medical Administration Office.