>> Today marks 25 years since the terrorist attacks of September 11th, 2001.

In a coordinated attack, terrorists four planes, crashing two into the World Trade Center in New York City, one into the Pentagon in Washington, D.C.

and the final plane crashed in Pennsylvania.

When the passengers on board fought back, former Wisconsin Governor Tommy Thompson was in Washington, DC at the time, serving as the secretary of Health and Human Services in the Bush administration.

Thursday, Thompson shared some of his memories of visiting New York City in the days after the attack.

>> Ladies and gentlemen, it was such a surreal.

Several days.

It's hard to really put it in words.

The feeling, the emotions, the.

The hatred, the sorrow that America was attacked.

It was like a like a pall had set in.

And the whole city, everybody wanted to get along.

Everybody wanted.

We walked down that thing and people were not talking.

They were not smiling.

They were just walking and.

And it was all the debris was, was flying down that beautiful day out there with the sunlight.

You couldn't see it.

It was just all obscure.

But the debris flying all over.

>> Earlier this week, New York City officials released 170,000 documents that were previously hid from the public, detailing their knowledge of how hazardous the air quality was at ground zero for both rescue workers and residents.

We asked former Secretary Thompson his reaction to that news.

>> It had to be obvious to everybody, anybody that was there, you know, during nine over 11, right after it, like I was, the air was so deleterious to a person's health.

I mean, you didn't have to be too smart to realize that some people were going to be adversely impacted.

And, I mean, the amount of debris that was coming out of the sky.

I mean, it was a beautiful day, like today in New York going up there.

But once you got there, it was just dismal because everything that was the sun was blacked out by the debris flying around.

And a lot of that stuff was hazardous.

And so you you can't discount it because I saw it.

I was witness to to that.

So it was obvious that the people were going to be adversely impacted health wise.

>> For more on this and other issues facing Wisconsin, visit our website at PBS