They snapped to attention and saluted as a firefighter rang the large silver bell -- the traditional 5-5-5-5 -- signaling a firefighter lost.
For several minutes, they stood motionless in honor of the sacrifices of the fallen heroes killed eight years ago today in the terrorist attacks. Chapel bells broke the silence briefly.
Later, church bells in nearby Emmitsburg were heard as well.
Some staff members watched the ceremony from windows of nearby buildings.
Kirby Keefer, a member of the USFA staff, struggled to keep his emotions as he remembered the fallen. He encouraged people to keep everyone who died on Sept. 11, 2001 in their hearts forever.
He urged them never to forget the police officers, civilians and brave people on Flight 93 who saved the nation from another horrific strike that day.
Though their Class A uniforms were dripping wet, none seemed bothered. For many of the honor guard, it was their first time to the National Fallen Firefighter Memorial.
Matt Weirs, a firefighter with Lewiston, Maine Fire Dept., said it was humbling to be at the memorial, especially on 9/11. "It was such an honor to be invited to participate in this..."
Over the past few days, the honor guard raised, lowered and folded U.S. flags that will be given to the families of fallen heroes during the annual national memorial service in October. They saluted as each was raised and lowered.
Firefighter J.P. Adams said it's hard to find words to describe what it's meant to him to be part of the memorial.
Carlos Ortiz said it meant a lot to him to be part of the effort. "We all shared in the tragedy that day. We are now a team," he said, looking at fellow members of the honor guard.
About an hour later, USFA and FEMA staff as well as AFG panelists gathered in the chapel to remember the heroes.
"Uncommon valor is a trait firefighters are known for...on Sept. 11, we witnessed the very essence of valor and courage in the face of horrific peril," said USFA Deputy Administrator Glenn Gaines.
Gaines challenged people to make sure "that every effort is undertaken to protect, educate and prepare this next generation of firefighters."
It was a truly emotional day for James Eastwood, a retired engine officer from Fairfield, Conn.
He spent a moment reading the names of people he knew on the plaques at the National Fallen Firefighter Memorial.
Then, he turned and walked to the huge 9/11 memorial. He was in awe.
"I stood on the brick path, and read the names again. So many. So many I knew in my career."
He spoke of Firefighter Chris Blackwell, who asked him how to get on the job. He took Eastwood's advice to study and test and made it on the FDNY.
"He got assigned to Rescue 3...They found him and his crew of eight three months later..."
Eastwood said Blackwell's teenage son now wants to follow in his dad's footsteps.
The Connecticut firefighter, who is on campus this week judging AFG grants, recalled lines from a song dedicated to the crew of Ladder Co. 105 in Brooklyn.
"Learn from every situation. It may save your life one day."
Eastwood added that as he stood before the giant sculpture of the firefighters raising the flag at Ground Zero, he promised that he will never forget.
Miami Firefighter Peter Schecter recalled his experience during a town meeting about technical rescue. It was rather heated, and he wondered how his former department would survive.
Later, he was approached by a fellow firefighter who encouraged him to get involved. That man, he would later learn was Chief Ray Downey.
Schecter challenged the group to take the step. "You can make a difference in someone else's career..."
Daniel Klein, a firefighter from Cologne, Minn., reminded people that the FDNY was involved in the most successful rescue in history eight years ago today. Because of their efforts, thousands were led to safety.
But, he added that there are many who are still suffering including families who lost loved ones, firefighters who retired after the tragedy as well as those brave rescuers who have fallen ill.