Nine New York Police Department officers who became ill after working at the World Trade Center site in the Sept. 11 recovery effort and then died have been honored at the city's Police Memorial Wall.

Mayor Michael Bloomberg and police Commissioner Raymond Kelly were at the unveiling ceremony in lower Manhattan on Thursday.

Bloomberg praises the officers' bravery, devotion and unselfish sacrifice.

Kelly notes those lost also were sons, husbands and fathers. He says besides working at the trade center site, they patrolled streets, subways and housing developments to make the city "safer for millions" of people.

Those honored were Inspector Donald G. Feser, Lt. Carlos J. Ocasio, Sgt. Alex W. Baez, Detective Corey J. Diaz, Officer Frank M. Bolusi, Officer Robert C. Grossman, Officer Richard Jakubowsky, Officer Robert Oswain and Officer Robert Zane.