Theresa Stack waited 15 years for this moment: witnessing firsthand how many people her husband’s life touched.

Hundreds of mourners packed the pews at Saints Philip and James Roman Catholic Church in St. James on Friday for the belated funeral of Lawrence Stack, an FDNY battalion chief who died when the twin towers collapsed on Sept. 11. New York City Mayor Bill de Blasio and FDNY Commissioner Daniel Nigro gave eulogies.

The memorial service began with a motorcade down Clinton Avenue, with several thousand firefighters filling four blocks. An American flag-draped casket, bearing the only traces of the fallen hero — two vials of his blood — arrived in the back of a fire truck.

Pallbearers included Stack’s sons, who followed him into the FDNY: Lt. Michael Stack, 46, and firefighter Brian Stack, 44.

“He placed himself at risk each day to preserve life,” the Rev. Thomas Haggerty said of Stack. “He lived out the oath he took each day of his life; he was dedicated to the FDNY.”

When planes hijacked by terrorists rammed the World Trade Center on Sept. 11, 2001, Stack, 58, of Lake Ronkonkoma, was working at his FDNY office in Brooklyn, where he investigated work-related accidents.

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He grabbed his gear and rushed to the scene to lend a hand. Witnesses last saw him helping to evacuate an injured man moments before the second tower fell.

“He knew he was needed,” Nigro said. “On his last day, he displayed every trait that made him so exceptional.”

Stack served the department for 33 years and died along with 342 of his fellow firefighters at Ground Zero.

Because Stack’s body was never recovered, the family couldn’t have a formal Catholic funeral. Last year, that changed — thanks to a lucky break.

Theresa Stack recalled that her husband had donated blood several years before his death. He had hoped to donate bone marrow to a local boy with cancer, but it turned out he wasn’t a match.

When the widow called the New York Blood Bank to inquire, they found that the samples given by Stack had somehow escaped destruction and were still in storage. Suddenly, the family had enough of their patriarch to lay him to rest. They scheduled the funeral to coincide with what would have been Theresa and Lawrence Stack’s 49th wedding anniversary.

In his remarks, de Blasio said Stack was “fiercely protective” of both fellow firefighters and civilians from the day he joined the FDNY in 1968. He’d always stop to help stranded motorists, whether on duty or not.

Despite often being immersed in tragedy — investigating firefighter deaths, Stack maintained a sense of humor, the mayor said.

Once, in response to a comment about being out of shape after a building evacuation, he referred to his unit as the “Clydesdales of this job” — a little slower, but effective at getting the job done.

De Blasio said Stack’s Labrador retriever Abby was often by his side, and he’d lead the safety battalion’s annual Christmas serenade, belting out holiday songs with 30 firefighters behind him at Rockefeller Center.

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“It takes a special kind of joy, an appreciation of all that life brings, to do something like that,” de Blasio said. “We remember that joy, and we can be inspired by that joy.”

In his eulogy, Michael Stack said he’s come to terms with the disappointment of his father missing 15 years’ worth of special moments.

The Yankees losing to the Red Sox in the 2004 American League Championship Series might have made him roll over in his grave, but he would have loved to see his grandchildren’s baptisms, Stack said.

Stack was later buried at Calverton National Cemetery in a private service that recognized his service in the Navy during the Vietnam War.

Michael Stack said he was finally at ease knowing his father would soon be in his rightful resting place.

advertisement | advertise on newsday

“Larry, it’s time — you’re going home,” Stack said, as mourners erupted in applause.

Theresa Stack waited 15 years for this moment: witnessing firsthand how many people her husband’s life touched.

Hundreds of mourners packed the pews at Saints Philip and James Roman Catholic Church in St. James on Friday for the belated funeral of Lawrence Stack, an FDNY battalion chief who died when the twin towers collapsed on Sept. 11. New York City Mayor Bill de Blasio and FDNY Commissioner Daniel Nigro gave eulogies.

The memorial service began with a motorcade down Clinton Avenue, with several thousand firefighters filling four blocks. An American flag-draped casket, bearing the only traces of the fallen hero — two vials of his blood — arrived in the back of a fire truck.

Pallbearers included Stack’s sons, who followed him into the FDNY: Lt. Michael Stack, 46, and firefighter Brian Stack, 44.

“He placed himself at risk each day to preserve life,” the Rev. Thomas Haggerty said of Stack. “He lived out the oath he took each day of his life; he was dedicated to the FDNY.”

When planes hijacked by terrorists rammed the World Trade Center on Sept. 11, 2001, Stack, 58, of Lake Ronkonkoma, was working at his FDNY office in Brooklyn, where he investigated work-related accidents.

He grabbed his gear and rushed to the scene to lend a hand. Witnesses last saw him helping to evacuate an injured man moments before the second tower fell.

“He knew he was needed,” Nigro said. “On his last day, he displayed every trait that made him so exceptional.”

Stack served the department for 33 years and died along with 342 of his fellow firefighters at Ground Zero.

Because Stack’s body was never recovered, the family couldn’t have a formal Catholic funeral. Last year, that changed — thanks to a lucky break.

Theresa Stack recalled that her husband had donated blood several years before his death. He had hoped to donate bone marrow to a local boy with cancer, but it turned out he wasn’t a match.

When the widow called the New York Blood Bank to inquire, they found that the samples given by Stack had somehow escaped destruction and were still in storage. Suddenly, the family had enough of their patriarch to lay him to rest. They scheduled the funeral to coincide with what would have been Theresa and Lawrence Stack’s 49th wedding anniversary.

In his remarks, de Blasio said Stack was “fiercely protective” of both fellow firefighters and civilians from the day he joined the FDNY in 1968. He’d always stop to help stranded motorists, whether on duty or not.

Despite often being immersed in tragedy — investigating firefighter deaths, Stack maintained a sense of humor, the mayor said.

Once, in response to a comment about being out of shape after a building evacuation, he referred to his unit as the “Clydesdales of this job” — a little slower, but effective at getting the job done.

De Blasio said Stack’s Labrador retriever Abby was often by his side, and he’d lead the safety battalion’s annual Christmas serenade, belting out holiday songs with 30 firefighters behind him at Rockefeller Center.

“It takes a special kind of joy, an appreciation of all that life brings, to do something like that,” de Blasio said. “We remember that joy, and we can be inspired by that joy.”

In his eulogy, Michael Stack said he’s come to terms with the disappointment of his father missing 15 years’ worth of special moments.

The Yankees losing to the Red Sox in the 2004 American League Championship Series might have made him roll over in his grave, but he would have loved to see his grandchildren’s baptisms, Stack said.

Stack was later buried at Calverton National Cemetery in a private service that recognized his service in the Navy during the Vietnam War.

Michael Stack said he was finally at ease knowing his father would soon be in his rightful resting place.

“Larry, it’s time — you’re going home,” Stack said, as mourners erupted in applause.

Theresa Stack waited 15 years for this moment: witnessing firsthand how many people her husband’s life touched.

Hundreds of mourners packed the pews at Saints Philip and James Roman Catholic Church in St. James on Friday for the belated funeral of Lawrence Stack, an FDNY battalion chief who died when the twin towers collapsed on Sept. 11. New York City Mayor Bill de Blasio and FDNY Commissioner Daniel Nigro gave eulogies.

The memorial service began with a motorcade down Clinton Avenue, with several thousand firefighters filling four blocks. An American flag-draped casket, bearing the only traces of the fallen hero — two vials of his blood — arrived in the back of a fire truck.

Pallbearers included Stack’s sons, who followed him into the FDNY: Lt. Michael Stack, 46, and firefighter Brian Stack, 44.

“He placed himself at risk each day to preserve life,” the Rev. Thomas Haggerty said of Stack. “He lived out the oath he took each day of his life; he was dedicated to the FDNY.”

When planes hijacked by terrorists rammed the World Trade Center on Sept. 11, 2001, Stack, 58, of Lake Ronkonkoma, was working at his FDNY office in Brooklyn, where he investigated work-related accidents.

He grabbed his gear and rushed to the scene to lend a hand. Witnesses last saw him helping to evacuate an injured man moments before the second tower fell.

“He knew he was needed,” Nigro said. “On his last day, he displayed every trait that made him so exceptional.”

Stack served the department for 33 years and died along with 342 of his fellow firefighters at Ground Zero.

Because Stack’s body was never recovered, the family couldn’t have a formal Catholic funeral. Last year, that changed — thanks to a lucky break.

Theresa Stack recalled that her husband had donated blood several years before his death. He had hoped to donate bone marrow to a local boy with cancer, but it turned out he wasn’t a match.

When the widow called the New York Blood Bank to inquire, they found that the samples given by Stack had somehow escaped destruction and were still in storage. Suddenly, the family had enough of their patriarch to lay him to rest. They scheduled the funeral to coincide with what would have been Theresa and Lawrence Stack’s 49th wedding anniversary.

In his remarks, de Blasio said Stack was “fiercely protective” of both fellow firefighters and civilians from the day he joined the FDNY in 1968. He’d always stop to help stranded motorists, whether on duty or not.

Despite often being immersed in tragedy — investigating firefighter deaths, Stack maintained a sense of humor, the mayor said.

Once, in response to a comment about being out of shape after a building evacuation, he referred to his unit as the “Clydesdales of this job” — a little slower, but effective at getting the job done.

De Blasio said Stack’s Labrador retriever Abby was often by his side, and he’d lead the safety battalion’s annual Christmas serenade, belting out holiday songs with 30 firefighters behind him at Rockefeller Center.

“It takes a special kind of joy, an appreciation of all that life brings, to do something like that,” de Blasio said. “We remember that joy, and we can be inspired by that joy.”

In his eulogy, Michael Stack said he’s come to terms with the disappointment of his father missing 15 years’ worth of special moments.

The Yankees losing to the Red Sox in the 2004 American League Championship Series might have made him roll over in his grave, but he would have loved to see his grandchildren’s baptisms, Stack said.

Stack was later buried at Calverton National Cemetery in a private service that recognized his service in the Navy during the Vietnam War.

Michael Stack said he was finally at ease knowing his father would soon be in his rightful resting place.

“Larry, it’s time — you’re going home,” Stack said, as mourners erupted in applause.