JOHN YANG: There was a solemn ceremony this morning in Oklahoma City.

It honored the 168 men, women and children who died 30 years ago when anti-government extremist set off a powerful bomb outside the federal building there.

It's still the deadliest act of homegrown terrorism in U.S. history.

In the keynote address, former President Bill Clinton reflected on the indelible mark the tragedy left on the city.

BILL CLINTON, Former U.S. President: I know you still miss the people you lost, but by continuing to love them and honor them and working to rebuild your own lives and the lives of this community, you've gone a long way to redeem the lives they were not able to live.

JOHN YANG: A single photograph captured the horror of that day.

A firefighter cradling the lifeless body of a small child.

It appeared on front pages and magazine covers around the country.

The firefighter in that photo is Chris Fields.

He's now retired after more than 31 years on the Oklahoma City Fire Department.

Chris, thanks for being with us.

And the memories aren't too painful.

I'd like you to take us back to that day 30 years ago.

You were in the firehouse.

As I understand it, you felt the concussion of the explosion and you headed to the scene.

You didn't wait for dispatcher to send you guys headed out on your own.

As you neared the building, what did you see and what was going through your head when you saw it?

CHRIS FIELDS, Former Oklahoma City Fire Department: My station was 17 blocks to the north, and as were getting closer, I remember reporting on the radio that were still 11 or 12 blocks away and storefront windows were blown out and people were kind of walking out in a daze.

No injuries.

And then as we approached the building, it was just like a scene from like a horror movie.

All these people running towards you, running away from the building and a lot of, you know, glass injuries, flying debris injuries and things like that.

JOHN YANG: And how was it that you were carrying daily the one year old girl you're carrying in the photograph?

How did that happen?

CHRIS FIELDS: We had been assigned to go to the south side of the building to catch up with some other crews and start doing some search and rescue operations.

And a police officer said he had a critical infant.

And I just put my arms out and said, here, I'll take her.

And first thing I did was check her for any signs of life.

I cleared some concrete dust out of her throat.

She had some other injuries, but I didn't find any signs of life.

And I went across the street to an ambulance and I told the paramedic, I have a critical infant and I'm waiting for him to get a blanket out of the ambulance to put her on the ground because the ambulance was full.

And you know, the next day, seeing the photo, finding out that's when the photo was taken, when I was standing there waiting for the paramedic to get a blanket.

JOHN YANG: You know, looking at that photo, the way you're cradling her, the way you're looking at her, it's like you're carrying your own child.

Do you remember what was going through your head at the time?

CHRIS FIELDS: Yes, sir.

Once I saw the photo, I knew exactly where I was standing and what I was doing and thinking.

My oldest son, who's 32 now, he was 2 at the time, so I knew they were close in age.

And most people know bailey had turned one year old the day before on April 18th.

I was just thinking that, you know, somebody's world, somebody's world is going to be turned upside down today.

Met the mother like a couple of days afterwards.

A reporter, a local reporter from here kind of set it up.

And at first I didn't want to.

I didn't know what I would say, what I would do, what their reaction was going to be.

Then the reporter said, well, the mother wants to meet you and the police officer and that changed everything because I said, well, that's what she wants and that's what we're going to do.

And we've maintained that relationship for 30 years as friends.

JOHN YANG: What did she say to you?

Do you remember?

CHRIS FIELDS: I do.

It's still a emotional meeting to think about.

Here was this 20-year old single mother, just lost her only child, comforting what are supposed to be these big, tough first responders.

And she just thanked us.

She thanked us that her baby was out and she knew the fate of her daughter.

She knew there were a lot of other families still waiting.

And as you tell, it's still emotional for me.

And she said that she could tell by the way were handling Bailey that were fathers and she appreciated the way we handled her.

JOHN YANG: You were not only a player in this horrific event, but you ended up by happenstance in the photograph that came to symbolize it.

How did those two things affect you?

CHRIS FIELDS: You know, I struggled for a while with the being singled out.

It's not something we look to do or strive to do or want to do in the fire service, but the support I had from my brothers and sisters on the fire department was overwhelming.

I struggled with a lot of the stuff about, you know, meeting Bailey's mother and knowing that, you know, I'm the last one that she knows that held her child and struggled with, you know, like I say, being singled out a retired fire chief really helped me.

And he said, you know what he sees when he sees that photo is the firefighter is not Chris Fields.

It's just a image of all the first responders that responded that day.

And he doesn't see Bailey Almond.

He sees her representing all the innocence that was lost that day.

JOHN YANG: You talked about the support you got from your brothers and sisters in the fire department.

You're sort of paying it forward now, aren't you?

You're working with first responders now.

Tell us about that work.

CHRIS FIELDS: Years after the bombing, you know, through the bombing experience and other things during my career, things kind of spiraled out of control in my life, my personal life, and diagnosed with PTSD, anxiety, depression, suicidal ideation.

I checked all the boxes and it was surely showing in my personal life, but through people reaching out to help me and me finally realizing I wasn't alone.

I wasn't the only one feeling that way.

I reached out, got the help I needed.

And I feel like that is -- that's what my calling is now, is to let other first responders know whether they're early, earlier in their career, coming from retirement, how many years they've got that all these feelings and emotions they have after some of the traumatic things we see and do over career, they're perfectly normal.

And they're not alone because you do.

Even though there's thousands of firefighters across the country, you feel like you're the only one feeling what you're feeling.

JOHN YANG: Chris Fields, thanks so much for sharing your memories with us after that difficult day.

Thank you very much.

CHRIS FIELDS: Thank you so much for having me.