Most high school seniors were about 2 years old when the 9/11 attacks occurred.

They and their younger peers have grown up aware of what happened, but not with the events of the day and the emotional toll it took seared into their memories.

Nazareth Academy parent Stu Breslow, who was at his desk on the 40th floor of Tower One of the World Trade Center when the first plane hit, shared his experiences with students on Sept. 12. His son, Brendan, a toddler then, is now a senior at the school.

Breslow said he felt the tower move but didn’t hear the impact when the first airplane tore through the building more than 50 floors above him. When the walls of his office started to crack and material began to fall from the ceiling, he saw debris falling from above outside the window. “I screamed for everybody to get out and headed for the stairwell,” he said.

He spoke of the confusion that reigned in the early moments. He first thought there had been an earthquake, he said. He left his laptop, car keys and BlackBerry at his desk, and was able to leave a voicemail for his wife, whose office in New Jersey had a clear view of the World Trade Center, that he was evacuating the building via the stairs and he would call again when he was safely out. Just after that call, all cellular service in the area was shut down.

As Breslow descended and the stairwell became more crowded, there was talk of a plane hitting the building, but people still didn’t necessarily think it was a premeditated attack, at least not until pagers started to beep with news alerts that the second plane had hit Tower Two. At that point, Breslow said, he became convinced New York was under attack.

By that time, he was stuck on the stairs on the 28th floor.

After a few more minutes, the call went up the stairs to move to the side to allow the firefighters to pass, he said. Fully loaded firefighters who were headed toward the inferno reassured the people on the stairs, he said, telling them, “You’re going to be fine.”

A colleague from Lehman Brothers had his BlackBerry with him in stairwell and was able to get an email out to Breslow’s wife, passing along the firefighters’ message and ending with “I love you and Brendan more than you can imagine.”

Eventually, the stairs cleared and Breslow — soaked by fire sprinklers — made it to his usual exit, but he was directed back into the lower level to a different door. When he finally emerged, he ran for several blocks before he heard the first tower collapse.

He took shelter in a synagogue, staying until the second tower collapsed and the rabbi told the people inside that they had to evacuate the building.

He made his way on foot to the Hudson River, where he was able to get to Hoboken, New Jersey by ferry.

For about two hours, his wife thought he was in Tower One — the North Tower — when she watched it collapse, he said. Breslow said he made it home by about 4 p.m., but then started eight hours of trying to track down the rest of the Lehman Brothers staff. Only one of the 500 people the company had in the World Trade Center that morning died.

That wasn’t his only friend who died.

“I had high school friends, college friends, fraternity brothers, people on my soccer team,” he said, among the 2,606 people who died in the World Trade Center. Overall, 2,996 people died in the attacks that day, including 19 hijackers.

Daphne Bigelow, a junior, said she learned new details from his presentation, including that the World Trade Center had been the target of terrorist attack in 1993.

“I never knew that before,” she said. “And about the courage and strength of the first responders. It’s added to the respect I have for them.”

Brooke Gawel and Ethan Willett, both seniors, said they have always been aware that Sept. 11 is an important and somber day, but it’s necessary to hear the stories of what happened.

“I didn’t realize how people were covered with ash,” Willett said.

“And the way they hosed them off” when they came off the ferry in New Jersey, Gawel said.

Therese Hawkins, Nazareth’s director of curriculum and instruction, said that as time has passed, it’s become clear how important it is to teach students about 9/11.

“It’s not so much that the way we teach about it has changed as that we really have to teach about it,” she said. She tries to prepare students for the graphic images that they will see, she said, and to emphasize that for many people, Sept. 11 has become a day of service. “We try to focus on things going forward,” she said.