NEW YORK (CBSNewYork) – By all accounts, the response by the FDNY to the attacks on the World Trade Center 20 years ago were incredibly heroic, and ultimately devastating.

CBS2’s Dana Tyler met with former Commissioner Thomas von Essen, for his reflections on that time, and the decades since.

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Whether walking by the reflecting pools at the 9/11 Memorial site, or in the hallowed halls of the National September 11th Memorial and Museum,  former FDNY commissioner Thomas Von Essen admits it all still has an enormous emotional impact on him.

“I just.. it was it was all very personal for me. You know,” Von Essen said.

“It still is,” Tyler said.

“Yeah, unfortunately, it still is,” Von Essen said.

Von Essen paid tribute at a pillar in the museum.

“There was so many… it’s just for me… I know too much,” he said. “It’s just dredging up all sadness and grief. For me, not the operational stuff. But the stuff that came afterwards: The families, the pain, the disappointment, all the – all the grief. And then so many stories this year of families and remembrance is when – been a rough, rough year.”

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He recalls the tragic events two decades ago, going over details, and remains confident there were sound decisions made.

“They knew early on, they couldn’t put the fire out. They knew that all the lines had been compromised, that there was no way of putting water on that fire, that explosion at 600 miles an hour. all those thousands of gallons of fuel. They knew they couldn’t put that fire out. But they still sent people up, to help people who needed it. And thousands of people were helped out,” Von Essen said.

“You’ve been very open about the radios, and the frequencies and the confusion, people not hearing each other. Talk to me a little bit about that,” Tyler said.

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“In an operation like this, all radios were not that great, but they were the best that we had,” Von Essen said. “So there will always be a criticism of radio or the operational part of it. But I think that, you know, a lot of a lot of the guys didn’t listen to the commands to get out. Because they were trying to help people.”

Another source of ongoing debate, and continuing heartbreak, was how the recovery on the pile was actually carried out.

“Well, I was down in the pile a lot. An awful lot. And I witnessed people that didn’t have the respirators on regularly. And it was hot, it was uncomfortable. They were trying to communicate with other firefighters. The chiefs would tell him ‘put your respirator.’ Chief would walk away, the respirators came off. It was just it was a tough time to have that discipline, in addition to the heartbreak that those guys were going through at the time,” Von Essen said.

For members and families of the FDNY, the loss – 343 – is a never ending source of sadness.

“How many eulogies?” Tyler asked.

“Dozens. Yeah, I don’t know. Forty, fifty. It was sometimes two a day, you know, and that was the hardest part,” Von Essen said. “And you stand up there, in the first row always seem to be some young, a woman with three little kids, and it was just horrible… or talking to the parents that, that they lost their son. It – that was the hardest part.”

Back outside the museum, the commissioner visited the names of firefighters lost that day, well aware of the personal story attached to each one.

“This guy here, worked with him in the South Bronx. Really good guy,” Von Essen said.

“Ray Downy was the head of special operations. And Ray said to me on the way out, he said, he said ‘Boy, you know, these buildings can come down.’ And he was on his way to the south tower when when it was hit,” he said when he came to Downy’s name.

“We all know this guy. I don’t know what to say about Father Judge,” Von Essen said, looking at FDNY Chaplain Mychal Judge‘s name.

But for the scope of the attacks, and the grueling rescue and recovery efforts that took place after, Von Essen does say there is one thing he might have done differently concerning the fate of his men he feared lost.

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“It’s not taking, telling the firefighters sooner, that we weren’t going to have any rescues, any survivors… And we were going to tell the families there’s no hope. And and the mayor walked in, he said they can’t handle it. Let’s wait. We waited another week,” Von Essen said. “But looking back at it, it doesn’t help. Bad news doesn’t get better… that’s the only real regret I have.”