NATICK, Mass. -- When his fiancée woke him up in their tiny apartment on that September morning 16 years ago, Chris Knox couldn't understand why she wouldn't let him sleep.

Knox had spent the previous evening at the New York City Fire Department's EMS Academy in Bayside, Queens, and he was tired. When she turned the TV to Channel 11, however, he saw why: a plane had struck the north tower of the World Trade Center in Lower Manhattan.

"Mayhem, just mayhem," Knox recalled. "So, I jumped in the car … and I jumped on the (Long Island Expressway), blue light flashing all the way into Fort Totten, where the academy was."

Eventually, Knox, then 20 years old, and the other academy students, just days away from graduation, were assigned to do triage near the attack site. Now a 36-year-old Army staff sergeant and Research Support Division NCOIC at the U.S. Army Research Institute of Environmental Medicine at Natick Soldier Systems Center, Knox well remembers how that day unfolded.

On their way into Lower Manhattan, the EMTs had to cross the Brooklyn Bridge.

"There wasn't a car on the bridge," Knox said. "It was just filled with people on both sides walking into Brooklyn. It was crazy. You've never seen that before."

The triage site was equally surreal, and no one came through for treatment.

"The air was smoky," Knox said. "We all wanted to go down (to the site). It just felt like not being able to do anything was driving everyone insane. It was pretty intense."

Finally, they were allowed to move closer to Ground Zero to help evacuate people and offer them masks so that they could breathe more easily in the dusty conditions. Knox never reached the site on that day, but later when he did, President George W. Bush had already visited, and the large American flag was on display.

"Cried like a baby," Knox said. "Lost friends. Lost peers."

Knox spent a great deal of time there in the coming days, weeks and months.

"You worked your eight-hour shift, and then you went to the site," Knox said. "Very rarely did you not do two tours in a day."

While at the World Trade Center site, Knox drove a small, red utility vehicle around the rubble as construction workers sifted through it.

"It's just a very sobering experience, being a 20-year-old kid and being involved as I was," Knox said. "It just blew my mind that this could happen. It's definitely an experience that I wish I didn't have to experience -- driving that little … Gator and picking up body parts.

"(The remains) would go back to a forensic lab that was onsite there, and they would identify who it was. And that was what we did the whole time."

Knox had grown up in Farmingville, N.Y., in a family of volunteer firefighters, himself included. But he was also an Army Reserve member on 9/11, and he went on active duty a year later.

"I always knew I wanted to serve in one capacity or another," said Knox, who has deployed twice to Iraq and once to Afghanistan. "I don't regret my choices at all. I love what I do now."

Time has taken away some of the sting of 9/11 for Knox, but he still carries it with him.

"New York has definitely not forgotten. That's for sure," Knox said. "I think one of the biggest things that really struck me, and that I remember to this day, is the outpouring from the community.

"It showed the strength of New York and what New York is really about."