Nearly 15 years after the Sept. 11 attacks, a funeral has been held for a New York City fire chief who died in the World Trade Center collapse.

The remains of Safety Battalion Chief Lawrence Stack were never found. But his family recently discovered two vials of blood that he had donated during a bone marrow drive for a child with cancer.

On Friday, several thousand firefighters lined the street outside the Long Island church where his funeral Mass was held. New York City's mayor and fire commissioner were among the speakers.

Afterward, the casket bearing the blood vials was placed on top of a ceremonial firetruck, flanked by Stack's firefighter sons.

The strains of bagpipes filled the air as the procession departed for Calverton National Cemetery.