(ominous music) - It looked like the foggiest day that you could imagine.

(ominous music continues) - What happened is the smoke couldn't go up, it couldn't dissipate.

(ominous music continues) - They were panting and they were scared to death.

(ominous music continues) - People became aware that there were a lot of people dying.

(ominous music continues) - And it was, unfortunately, a recipe for a disaster.

- [Newscaster] Go to press.

Donora, Pennsylvania.

Health officials now fear an ammonia epidemic in Donora, where the death toll from a smothering fog has reached 20.

- [Narrator] It was the fall of 1948 when that deadly smog descended on Donora.

Toxic fumes from a zinc plant and other nearby mills hung over the area for five days.

When rain finally cleared the air, 20 people had died.

Thousands more were sick.

(ominous music continues) (car whooshing) Today, most people don't know about the Donora smog.

Some know it as a footnote in history, and very few know how the tragedy changed the way we live and breathe, except for those who lived through it.

- Just can't get over the green over there and Webster on top of the hill.

Everything was dark brown.

- Yeah.

- Was dirt.

- Yep.

- [Narrator] Jean Davis is back home.

She hasn't seen Donora in decades.

Jean raised her family there and returned with her daughter Devra for a look at the old neighborhood.

- [Devra] I remember the house was there, where your mom lived and she got sick.

- [Narrator] They talk about the Donora of yesterday.

- [Jean] My mom, we all grew up there.

- [Narrator] They remember life in a small town, settled on the steep hills above the Monongahela River.

- [Jean] You know, I used to walk up and down these steps four times a day to go to Kassner's school on 10th Street.

- [Devra] How many steps were there?

- [Jean] 105.

- [Devra] 105.

Why'd you keep counting them?

- I don't know, I guess it helped pass the time - [Narrator] For Jean, this homecoming is about more than memories.

She walks with a sense of pride because of her daughter, Devra Davis, student at Donora's old Sampson Star School graduate of the University of Pittsburgh, epidemiologist, and one of the leading authorities on environmental dangers.

Davis is now telling the Donora story in her book, "When Smoke Ran Like Water: Tales of Environmental Deception and Pollution."

- We had great hills for sliding down, 'cause of course nothing grew on many of them.

They were just barren dirt and kind of steep, like right here.

- [Narrator] Growing up in Donora, Devra Davis thought the smoky skies and dusty hillsides were normal.

- Well, if you lived here, it smelled just fine.

- [Narrator] She never noticed the stunted trees or the stink of the mills.

- People would come to the town and they'd say, "What's that smell?"

And people who lived here would say, "What smell?"

And my grandpa would say, "Well, it smells like money."

(film clicking) (dramatic music) - [Narrator] The Donora Zinc Works was making money, and like the mills in most steel towns, it loomed large in the community, physically and economically.

The plant pumped out salaries along with smoke and toxins, 24 hours a day.

- The zinc plant actually was over there.

Of course, now you can't see it 'cause it's so green.

And it had stacks that were 110 feet high.

- [Narrator] Everyone in the valley knew those stacks emitted something unhealthy, and all they had to do was follow the smoke, which usually blew across the river to the small community of Webster.

- [Devra] Webster was right downwind of the plume from the Zinc Works.

It was totally barren.

- [Narrator] Treeless hills, soot-covered buildings in the shadow of a hulking structure on the riverbank.

Ugly by today's standards.

But the people of Donora chose to celebrate the beauty of the Zinc Works and its contribution to the community.

- When the mills were working, people had jobs, and this is a hardworking town.

People who lived in Donora had to be pretty hardy.

- [Narrator] Not hardy enough, though, to withstand what happened just before Halloween in 1948, when a deadly air inversion settled over the valley.

- These hills here, they're not very high, but they're high enough that the cold heavier air rolling off those hills could smack down the hot fumes coming out of those zinc stacks, so that you had a static level of air sitting there over those hot fumes for five days.

- [Narrator] At first, nobody noticed.

Visibility was just worse than usual.

- It was around Halloween time and the kids were all excited they were in a parade and you didn't have to make it spooky.

It was already spooky 'cause you couldn't see very much.

It had a very eerie feeling.

(crowd cheering) - The football game went on because nothing ever stopped football in Donora or Monongahela.

- [Tony Romantino] Bernie Richardson, Joe Wittisesky, Mario Protfetto, myself, Andy Kazimpka- [Narrator] Tony Romantino remembers his high school teammates like it was yesterday.

He played right guard for the Donora Dragons in what some call the best football game that was never seen, the Dragons against the Monongahela Wildcats.

(ominous music) Tony says, practice at Legion Field the day before was especially bad.

- We lined up for kickoff.

One team on the 40, the other team on the other 40.

There's 20 yards that separate us.

Could not see each other.

Could not see each other.

(ominous music continues) - [Narrator[ Despite the fog, the rivals went at it.

(group chattering) Fans packed the stadium and Mon City won.

(crowd cheers) - They gave us our worst whipping in three years.

We were not focused.

I mean, there were too many things happening.

- [Narrator] Word was starting to spread.

The blanket of fog was making people sick.

Still, sulfur, carbon monoxide and heavy metal dust kept pouring out of the plant.

(ominous music continues) - I was a nurse at the Donora mill.

- [Narrator] Eileen Loftus was a young woman then, in charge of the nursing staff.

She was called to duty when gasping mill workers crowded the infirmary.

- [Eileen] And my mother said, "Don't go to work."

I said, "I have to go to work."

- [Narrator] Even at the age of 85, Eileen says she'll never forget walking to the plant through a blinding cloud.

- So I walked up Thompson Avenue to Eighth Street and I touched the houses as I went along to make sure I was still on the sidewalk, and I just felt my way along the fence.

I couldn't see.

(siren blares) But in no time, the hospital was jammed.

I even put some of them on the floor.

I had to because there was no place.

They wanted to know if they were going to live or what.

And I said, "You're going to live if I can help it."

But I really...

I talked to them and I sort of eased their minds a little bit.

- [Speaker] You think this was used as a temporary morgue?

- Yes.

- [Narrator] When the funeral homes ran out of space, bodies were taken to the community center and emergency workers struggled to keep the death count from rising.

(bell ringing) - The fire bells rang, (siren blaring) alerting us to an alarm.

- [Narrator] Bill Schempp no longer answers fire alarms.

He spends his days tinkering with the classic 1947 fire truck that he's proudly restored.

Bill has served the Donora Fire Department for 56 years.

(siren blares) That's him 20 years ago, when a building caught fire on McKean Avenue.

Here's Bill on a vintage fire truck in 1948, - And I was young and wanting to do all I could.

- [Narrator] 48 was the year Bill Schempp carried oxygen to smog victims door-to-door on foot because he couldn't see to drive.

- I had to feel my way.

There was no way that you could see where you were going.

I had a handkerchief that was wet.

I had part of it in my mouth and the rest was over my nose.

I got to the point of where I was on the verge of panic myself because once I started, I had no idea of where I was.

The town was shut down and people were not out on the streets.

They were all in their homes and told to keep their windows closed.

You would be amazed at how eerie the feeling was.

It was a sensation.

There was no noise, no nothing.

There were no vehicles operating at all.

(bell rings) (bell ringing continues) - [Announcer] 20 funerals, grieving families, national headlines.

That's what it took to temporarily shut down the zinc plant, and there was no real way of proving cases of long-term exposure.

- At that time, I was going to junior high school in Donora.

I was in ninth grade.

- Dimitri Petro is a doctor now.

He set up practice in his hometown.

- Now I'm seeing a lot of people with chronic lung disease who live in this Mon Valley area, as a result of all the mills.

- The death certificate said heart attack.

- [Narrator] Football player Tony Romantino's father worked at the zinc plant and died just weeks after the smog lifted.

- I can't say for certain that he died because of the smog, but it did have an effect on him.

It slowed him down.

- A federal team moved in to examine the survivors and test the air.

The Donora Zinc Works finally closed for good.

The town gathered to watch its demolition.

(dramatic music) (chimney crashes) But there was no celebration.

The smog victims are now faded images in old newspapers, names long forgotten by most, but their deaths sent the world a message that still lives today.

(dramatic music continues) - Oh, I don't think they died in vain.

I think in fact, we saw the beginnings of a lot of legislation to clean up the air.

And in fact, the whole Allegheny County-Pittsburgh area became a leader in clean air legislation.

- It brought a lot of things to life.

They had the federal government come in with representatives.

It made the people begin to realize what they were breathing.

- The nation learned quite a bit.

That led...

The deaths in Donora led to the passage of the Clean Air Act.

- People understood that they had to do something different.

I mean, Donora was a healthy working-class population, and if people here who were steelworkers and football players would die from pollution, this was a very serious problem.

- We had a sense of community and they were really not aware of the fact that living here was really treacherous to your health.

(gentle music) I had many good friends.

- [Devra] Yeah.

People took care of one another.

(gentle music continues) This community is still surviving.

(gentle music continues)