Standing at the window of their seventh-floor apartment at the corner of Greenwich and Murray streets on September 11, 2001, Tracy Spinney and Stacie Myszewski could just watch as men and women leapt out the windows of the World Trade Center’s towers. They felt helpless, but as they recorded their story, the couple’s voices lost their quiver and adopted the vague but unmistakable timbre of understanding.

“Everyone was flooding out past me, there were dust-covered people, there were bleeding people, there were people without their shoes,” Mr. Spinney said, hunched over a small table in StoryCorps’ wood-paneled, soundproof recording booth at the World Trade Center PATH station on July 21. Sitting opposite Mr. Spinney, who was her fiance at the time of the attacks, Ms. Myszewski remembered running between the window and the television, which broadcast the incomprehensible scene she was witnessing.

“Her skirt would fly up,” she said. “You could see the color of their ties.”

Mr. Spinney recalled a lone man leaning out a broken window on the 108th floor, waving a white ceiling tile to attract the attention of a helicopter that never came.

“He was so familiar to me,” Ms. Myszewski said.

A gentle voice interrupted the couple’s flashback. “What was going through your minds?” a 25-year-old StoryCorps facilitator, Veronica Ordaz, said.

“I knew I wasn’t going to die,” Ms. Myszewski answered. “There was just so much coming at you all at once. I hadn’t even started crying yet.”

After the 40-minute interview, Ms. Ordaz handed Mr. Spinney, a voice-over artist, and Ms. Myszewski, a floral arranger, a CD that contained their recorded story, and she thanked them for participating in one of the largest oral-history projects ever undertaken.

“I need a second,” Ms. Ordaz said, sighing and sinking onto a metal bench. “Whew.”

A copy of the Spinney-Myszewski CD, along with every other StoryCorps interview, will end up at the American Folklife Center at the Library of Congress in Washington, D.C. Snippets of StoryCorps interviews are also broadcast on National Public Radio’s “All Things Considered” or “Morning Edition.”

The StoryCorps booth at ground zero cost $250,000 to build, a spokeswoman for the organization, Johanna Flattery, said. That is half the sum of a grant received from the Lower Manhattan Development Corporation for construction and operating costs through December 31. The booth opened July 12, and already 60 people have passed through, recording their stories for posterity and for themselves. The interview subjects are asked to contribute $10 toward StoryCorps’ expenses.

The project began October 23, 2003, when a radio documentary-maker, David Isay, opened a booth at Grand Central Terminal so that the public could make permanent the richness of their everyday experiences. Mr. Isay aims to record 5,000 interviews from the booth at ground zero, and 250,000 interviews in all. The Lower Manhattan Development Corporation asked StoryCorps to bring a booth to ground zero to provide an outlet for families to talk about lost loved ones and to record many perspectives of one traumatic day, Mr. Isay said.

“Families who haven’t been down since September 11 are coming. It’s almost a spiritual thing already, this destination,” he said. “The idea of closure just doesn’t happen. They don’t really want therapists, they’ve had their therapists, and they are not looking for someone in a white lab coat to take their pulse on this. What they want is just an opportunity to talk and to remember.”

Facilitators, such as Ms. Ordaz, are chosen carefully to be, in essence, professional listeners. Often passive participants, they operate the recording equipment if two people come in to tell a tale together, and they act as both interviewer and technical overseer if a solo storyteller comes in. Despite its emotional strain, the job is desirable, Mr. Isay said – he went through hundreds of applications before he hired 13 facilitators.

A week-long training session covered everything from audio editing to tips on how to talk to a participant coming to terms with death. Recommended reading includes works by some longtime writers at the New Yorker magazine, Joseph Mitchell and A.J. Liebling; “Let Us Now Praise Famous Men,” by James Agee and Walker Evans, and several field guides from the Depression-era Works Progress Administration, which conducted a similar oral-history project.

Facilitators sit through interview after interview, soaking up dozens of stories. In one afternoon at the booth, a woman described how she jumped into a boat in the Hudson River as she fled from the dust cloud, and another teared up as she explained why she was afraid to raise her child in a city tainted by terrorists. In the 15-minute respite after Mr. Spinney and Ms. Myszewski’s interview, Ms. Ordaz needed time to recover, calling the experience in the booth “intense.”

“You get emotionally involved,” she said. “Because of how intimate the space is, you absorb their energy. Just seeing their expressions, I become involved. I don’t necessarily have to say anything.”

“It’s a very difficult job,” Mr. Isay said, “and the intensity of what’s been happening at the World Trade Center is even more than any of us had expected.” In response to the emotional drain on the facilitators at the booth, Mr. Isay said one midday interview slot was dropped, to give facilitators a rest.

Another facilitator manning the ground zero booth with Ms. Ordaz on July 21, Nick Yulman, said it is hard to remain a detached listener.

“You can’t help but be pulled in to a lot of these stories,” he said. “It’s kind of corny, but it’s part of the soul. You learn a lot about somebody just in the grain of their voice.”

Mr. Yulman, 25, who has always nurtured an interest in radio production, said he thinks about his role as a facilitator on a scale that ranges from the shortterm to the timeless.

“How do these stories translate into radio, or historically?” he said. “What little details, years from now, are going to be astounding?”

Often, participants who have talked for 40 minutes about their own experience open up to everyone around them, including the usually silent facilitator, who sits in the corner with a headset, hunched over a clipboard, taking notes about what topic is being discussed at different points during the tape feed.

StoryCorps’ concept of history is one in which minute details pale in importance compared to the participants’ comprehension of their experiences, and their ability to find closure.

“The questions people are asking in the booth aren’t necessarily the specifics of history, but what have you learned in life,” Mr. Isay said.

During the last few minutes of their interview, Mr. Spinney and Ms. Myszewski mulled over Ms. Ordaz’s final question to them: “Did all of this seem real to you?”

“No, it still doesn’t,” Mr. Spinney said.

“Like I almost made this up, when I tell people about it,” Ms. Myszewski.

“Little things keep coming back to me,” Mr. Spinney said.

“And the smell, we didn’t even talk about the smell,” Ms. Myszewski said. “I wouldn’t have wanted to be anyplace else in the world. My mother doesn’t want to hear my story. I am so glad it’s a part of me.”

“It’s hard to know our current days are different because of what we witnessed,” Mr. Spinney said. “I’d like to let go of it, but I carry it around with me still. That’s all I have to say.”

After Mr. Spinney and Ms. Myszewski left the metallic booth, clutching their CD, Ms. Ordaz and Mr. Yulman conducted two other interviews. As commuters started to flood the PATH station, Ms. Ordaz greeted the last interview of the day, Carmen and Jose Bonilla. Mr. Bonilla, who lives in New Jersey with his wife and two sons, worked for Blue Cross Blue Shield and escaped from the 29th floor of the North Tower on September 11.

“Paint pictures,” Ms. Ordaz suggested before their interview began. “There’s no right or wrong way to do this interview. There’s no way to mess this up.”

Shutting the booth for the day, she said she hoped StoryCorps transforms its participants as much as it moves her.