♪ ♪ >> NARRATOR: Tonight, two stories in this special edition of "Frontline."

First... >> I was scared that I was dying, and I was.

>> NARRATOR: Thousands of coal miners are suffering from a severe form of black lung disease.

>> It was something that we thought had been relegated to the trash heap of history.

>> NARRATOR: "Frontline" and NPR investigate evidence going back 20 years.

>> Why won't you talk to us about this issue?

>> NARRATOR: And how the industry and the government failed to protect miners.

>> This is a gross example of regulatory failure.

>> NARRATOR: And later tonight-- the U.S. fight against Al Qaeda in Yemen.

>> AHMAD: The people who lived in the village described an apocalyptic scene.

>> NARRATOR: Correspondent Safa Al Ahmad investigates the toll on civilians.

>> AHMAD: The drone strikes, the raids adds to the massive fear and confusion Yemenis are already feeling in the midst of this very complicated war.

>> NARRATOR: These two stories tonight on this special edition of "Frontline."

♪ ♪ (lawn mower whirring) (man coughing) >> I've mowed that bank right there since I was a little boy.

Lord, eight or nine years old.

It's just a simple task to most people, but to me this is something, it's like a challenge that you have to get through.

I believe fully if I hadn't really got up and started moving around because I was so sick, I would have sat in my chair and died.

And things like this right here, I get up and it gives me, I motivate myself to do it.

(coughing) (grunts) (sniffles, catches breath) (coughs) (clears throat) >> HOWARD BERKES: During the past six years, I've been in and out of the coal fields of West Virginia, Virginia, Kentucky, and Pennsylvania, meeting sick and dying coal miners.

At first, I reported for NPR the resurgence of a deadly coal mining disease, black lung, which had been declining for decades.

Then I got a tip two years ago about an outbreak of the most advanced form of black lung disease and I began looking into why it was happening.

So this morning we're headed to visit with Danny Smith.

He's a young guy.

He's younger than what you'd expect for somebody to be so sick with this disease.

So you said you had a rough time last night?

>> Yeah.

I sleep in my chair, but... >> BERKES: So you sleep out here in the living room in a chair?

>> Most of the time I sleep in a recliner, yeah.

>> BERKES: Danny Smith is just 47 years old.

He mined coal only 12 years, but he's desperately sick.

>> Are you ready, Sissy?

>> Yeah.

>> Well, let Daddy turn his oxygen off and I'll get my stuff ready and we'll go.

(grunts, coughs) I started getting shortness of breath around 2007, 2006.

I could tell a difference in just the things that I was doing around here.

>> Do you want me to get this?

>> The oxygen?

Yeah, I need it.

And in 2012, I believe it was, they'd done a CT scan, and they seen all the spots on my lungs.

They said, "It's black lung.

You're eat up with black lung."

That put me in the hospital.

I had 30-some pounds of fluid on me, on my lungs.

I'm not feeling good today, baby.

Didn't sleep good.

I was scared.

It was tough on all of us, because my wife was scared that I was dying, and I was scared that I was dying, and I was.

(clears throat, coughs) Can you turn that oxygen on back there?

Just pull that little green handle.

Just pull it, like, towards you.

(clears throat) There we go.

Now I gotta get it on my face.

(chuckles) I think about all the hours that I worked.

I was under one month, I never come outside for four days.

I actually slept underground.

And you sit and think about that, and all the things that I give up with my family, you know, by working anywhere from 12 to 18 hours a day.

I'm dying over it now, you know what I'm saying?

I love you.

Give me a kiss!

(clears throat) (coughs) (exhales) >> BERKES: As I met more miners like Danny Smith, it became clear that they were getting this advanced black lung disease younger and more quickly than in the past.

Greg?

>> Hey.

>> BERKES: I'm Howard Berkes from National Public Radio.

Great to meet you.

>> Uh-huh.

>> BERKES: Greg Kelly is just 54 years old, still relatively young for a miner so sick.

>> That's me and that's my stepdad.

>> BERKES: How long did you spend in mining?

>> 31 years.

Here's one.

That was in '83.

>> BERKES: And what made you stop mining?

>> My health, I just couldn't, I got sick.

They said, "We don't want you to go back to work until you see a lung doctor."

When I did get to see him, he said, you know, "You don't need to go back underground."

>> BERKES: Was that the first time you learned that you had black lung?

>> Right.

Yeah, that's the first doctor that ever said, "You've got black lung."

I've had two or three x-ray technicians tell me they're the worst set of lungs they've ever seen.

>> BERKES: What kind of reaction did you have when you heard about that?

>> (voice breaking): You can't work.

It's just like a light switch being turned on and turned off.

All your plans that you had, you know, hunting and fishing and doing what you want to do, when that day comes, well, all of a sudden it's here and you can't.

You don't have the air to do it.

(birds chirping) You know, I still enjoy life, have a good time, get to play with my grandson, just not like I want to and like I used to be able to.

Catch one?

There he is, you got him.

But I just try to pray and ask the Lord to help me to overcome it.

And just go on and be with my family.

(water flowing) (grunts) You got one, didn't you?

The whole time I'm bent over, I can't breathe.

And then when you raise up, you got to stand still till you get your breath.

Come on, let's go show Mom what you caught.

>> It was kind of rough because I was in Texas when a lot of it first happened, being, you know, pretty far away from home.

And Caden, he had to adjust with... he had...

When he first brought oxygen home or whatever, Caden asked, "When's he gonna get better?"

You know, "When's he gonna be able to go out and play like we used to?"

That's when we had to tell him, you know, it never will change.

You know, it'll be the same.

It won't get no better.

>> That's probably been the hardest ordeal, is my grandson.

(cries softly) ♪ ♪ >> The disease that steals the breath of coal miners is back with a vengeance.

>> BERKES: Across Appalachia, I met dozens of other miners with this advanced black lung disease and started reporting their stories.

Basic black lung diagnoses doubled in the last decade.

Advanced disease quadrupled since the 1980s in Virginia, West Virginia, and Kentucky.

One in five working coal miners in Appalachia could have diseased lungs.

That's true for the thousands who've been tested and it could be the rate for the rest.

The more I reported, the more it became clear it was worse than anyone realized.

"Go see Brandon Crum in Kentucky," I was told.

He's a radiologist whose clinic is overwhelmed with cases of advanced black lung disease, known as progressive massive fibrosis, or PMF.

>> So, I'll just show you, for comparison, this is a normal x-ray.

And you can see all the dark area, that's the lung, 'cause it's filled with air.

And you contrast that to this one.

All these, you see all these big white areas, all the way through here?

That's all conglomerate fibrotic mass, or PMF.

The biggest concern at that time, for me, was seeing young men my age, and I'm 43, or younger than I am, with the most severe form of the disease, which is the complicated black lung disease.

>> BERKES: Crum was so concerned, he took his findings to researchers at the National Institute for Occupational Safety and Health, or NIOSH.

So what happened two years ago in terms of you sitting down with people from NIOSH?

>> Well, when I told them, you know, we were seeing, or I was seeing, a lot of complicated black lung disease, and what was most concerning is I was seeing it in individuals in their 30s and 40s.

I think there was some hesitancy on their part.

I'm not sure they believed me.

>> He told us that he was seeing a lot of really advanced disease and it was concerning to him, and I guess my initial thought was that's probably not true.

>> BERKES: The researchers had been tracking black lung disease themselves for decades.

But they only tested working miners, not those out of work and hadn't detected the sharp rise in deadly PMF that Brandon Crum was finding.

>> He invited us to show us some of the medical images from his patients, and we sat there for an entire day, one after another after another, looking at these chest x-rays, the worst I've ever seen.

>> BERKES: What was your reaction to what you saw?

>> Horror.

Shock.

I don't know how other... many other words to use.

I was really taken aback, not only that these cases were legitimate, but just how severe they were.

It indicated that we had a huge problem, and we realized immediately that it wasn't going to be isolated to a single clinic.

(birds chirping) >> BERKES: Researchers at NIOSH had only reported 99 cases of PMF in the previous five years, but out-of-work miners had been flooding clinics, and in calls and visits to 16 clinics across Appalachia, "Frontline" and NPR identified close to 2,000 cases in the same time frame.

The Stone Mountain Clinics in southwestern Virginia reported more cases than anyone.

Ron Carson directed the clinic at the time.

>> We're gonna put you in a room.

Come on with me.

When NIOSH reported maybe 90 or 100 x-rays... >> All right, if you can step up real close for me.

>> We came back and we started doing a study on how many we actually had, pulling x-rays back to 2014 to 2017, three years of x-rays.

We quickly identified 416 during that three-year period.

However, if we had went back to 2010, at a minimum, we could have probably doubled that.

>> Breathe in and out, deep and fast.

(man breathing rapidly) >> In and out.

And... stop.

>> I don't know what your test will reveal today, but I tell everybody this for almost 30 years: don't get discouraged.

>> BERKES: But the count here at Stone Mountain is now nearly 800, with a dozen new cases a month.

>> My buddy here.

Okay, God bless you... >> Thank you, darling, God bless you.

>> I just think that America needs to know that these miners, they have paid a price.

So many years, these miners extracted this coal so that you and I can...

I'm getting teary-eyed.

(exhales) (softly): I'm sorry.

(sighs) They paid a price.

They have paid a price so that we can have luxury.

♪ ♪ And I just feel like America has just forgotten about them.

>> ...a sec.

>> So let us trust in you and you only.

Despite what's going on around us, give us the joy and the peace that the world cannot give us.

And we thank you for your love that is unconditional.

In Jesus' name we pray.

Amen.

(machine beeps) >> BERKES: With no cure, Danny Smith finds some help with his breathing at a pulmonary rehab clinic.

Miners come here as much as four days a week and they're monitored closely.

>> Marcy?

>> He wants to drop down.

>> Can I drop down today?

'Cause I'm wore out.

>> Yes.

Yes, you can, yeah.

What's Danny's heart rate?

96?

Just stop and catch your breath there for a second.

Danny, when he first started with us, he would break out in a cold sweat, literally drenched, and he would start shallow breathing.

Depression, anxiety-- you know, that is, that is much a part of this disease as the breathing is.

Then we'll, we're going to turn it way down, okay?

>> All right.

Yeah, that feels pretty good right there.

>> It takes them approximately three to six months to build up when they start this program.

At six months, they're typically maxed out.

If they're out for two weeks, they lose pretty much everything they gained.

Once they go into... >> Yeah, if I miss one or two visits, I can tell, I mean, it's affected me.

>> You did it!

Ten minutes!

>> Yeah, I got it.

>> These men, literally, if they go home and they sit down, they've got about six months to live.

>> If I hadn't started here, I'd already been dead.

>> He would have.

I believe that, too.

I do.

>> I love y'all.

Y'all are my angels.

>> (chuckling) >> See y'all.

(sighs) (clears throat) >> When people get the first stages of the disease, they require oxygen.

And then even the oxygen that you're adding to that person so that they can do more isn't enough.

And so they're essentially suffocating while alive.

Something seemed to change where people were more heavily exposed to perhaps more toxic dust, and were getting this very severe form of the disease that, from my medical school training and from my past clinical practice, was rare.

We didn't see that many cases of PMF and it was something that we thought had been relegated to the trash heap of history.

(men chanting) >> BERKES: The modern era of coal mine regulation began nearly 50 years ago, in part because 40,000 coal miners staged a wildcat strike in West Virginia, demanding government action on black lung.

>> The greatest heroes are you the coal miners.

You've taken the future, your future, in your hands, and you have proclaimed, "No longer are we gonna live and work and die like animals."

We're free men!"

(cheering and applauding) >> BERKES: Congress responded with a tough new law that was supposed to protect miners from the coal mine dust that poisons lungs.

And in the early '70s, a new federal research agency, NIOSH, began to monitor black lung disease among working miners.

>> We saw that nice reduction in the rates of disease, falling down to very low levels.

And then that...

I call it the U-shaped curve of concern, the curve went down and hit the bottom and then started to go back up again, meaning that something changed.

We took our eye off the ball, something else happened, and the disease was recurring.

>> BERKES: What changed was mining itself.

Big and pure coal seams were mined out.

Thinner seams embedded in rock were left.

Mining machines cut more and more of that rock, producing fine and sharp particles of quartz or silica-- toxic dust that the existing mining regulations didn't directly control.

>> Somewhere in the late 20th century, there has been a change in the composition of the dust.

We're seeing more silica, and silica is 20 times more toxic than coal.

When you inhale silica, it's retained in the lung.

These miners are inhaling their workplace and it stays with them forever.

>> BERKES: By the mid 1990s, federal regulators knew there was a problem.

NIOSH recommended new silica regulation, including an exposure limit twice as tough.

But the proposals didn't go anywhere.

So you worked for the agency back in this time frame.

>> Mm-hmm.

>> BERKES: Why didn't the agency respond to this?

>> There was a lot of reluctance both in the mining industry and I think also from the mine workers' union about the, what they would call complexity of really doing both a coal mine dust standard and a silica standard.

Now we see in miners who were, again, working at that period of time and now are the ones that are seriously ill from that disease.

>> BERKES: They're dying.

>> Yeah.

>> BERKES: Terrible deaths.

>> Yeah.

Had we taken action at that time, I really believe that we would not be seeing the disease that we're seeing now.

>> BERKES: It wasn't until 2014 that the Mine Safety and Health Administration, MSHA, put in place new restrictions on coal mine dust.

But, again, something was missing.

This is the new dust rules that took effect in 2014.

What's interesting is this section here, where MSHA said it wasn't establishing a new limit for quartz or silica.

Instead of imposing specific new limits on silica dust, regulators continued to rely on rules that control coal mine dust overall, and a complex formula to measure exposure that dates back decades.

We decided to see if this approach had really worked using MSHA's own data.

This is the formula that's actually still in use.

And what our data shows, what MSHA's data shows, is that that formula hasn't worked 9,000 times since 1986.

We can see it in the data.

It's kind of puzzling why they didn't see it in the data, and why they don't think this is important enough to have a different kind of regulatory process.

>> We do have a new respirable dust rule.

I say it's new.

It's 2014.

>> BERKES: Greg Meikle is responsible for coal miners' health at MSHA.

I sought interviews with him and other agency officials for months, without any success, until this annual West Virginia black lung conference.

Greg, I'm Howard Berkes from NPR and PBS "Frontline."

>> Hi, Howard.

I have not met you.

>> BERKES: We have not met, but I have wanted to talk to you and I'm going to take advantage of that right now.

You said that you need to establish an incident rate before you can respond as a regulatory agency.

What do you mean, exactly?

>> Well, incident rate is how many miners... if we'd have no miners that are diseased, then the protections are effective.

>> BERKES: Well, you have lots of miners with disease.

So that means the protections are ineffective?

>> We've got a new rule.

The old... old rule, we had some problems, and that's why we went to the new rule.

>> BERKES: The new rule doesn't measure separately for silica.

That's what's still in place.

That was what is, was in place in the old rule, and we have thousands of miners who have progressive massive fibrosis.

Doesn't that need to be changed?

If the problem here is silica, don't you need to separately regulate silica?

>> Well, under, in the preamble to the new rule, it said that quartz was not being addressed.

>> BERKES: In the new rules, MSHA officials cited research that said coal mine dust was the main factor in black lung and PMF, and they continue to stand by that idea that limiting coal dust overall protects miners from excessive exposure to silica.

(train brakes squealing) As for the coal mining industry, it once proposed focused regulation of silica.

But mining companies continue to cut thin seams and create toxic silica dust.

>> We sympathize with those individuals, with those families.

If we could turn back the hands of time, we would do so to prevent this.

But, you know, we can't.

We're dealing with historic exposures.

And from our perspective, what we need to be focused on today is: how do we prevent a reoccurrence of this?

>> BERKES: You've talked about the idea of looking ahead.

But what we see as we look at data of exposures, and it shows that there were thousands and thousands and thousands of exposures, not 30 and 40 years ago, but also 20 and ten years ago.

And the industry knew that mines were cutting more and more rock, which was creating this silica.

Why didn't the industry recognize what was going on and do something about it when it was taking place?

>> Well, I don't...

I don't think it's entirely fair to say that the industry didn't recognize and didn't do anything.

You know, for a long period of time, we've been pleading-- and I'll use that word-- we've been pleading with the agency to allow us to use nontraditional controls for dust control.

>> BERKES: You can slow down the mining machines.

You can maybe cut production a little bit so that you're not generating as much dust.

Or maybe you decide that you don't cut so much rock and you don't cut those thinner seams.

Aren't those things that mining companies could have done?

You don't need regulation to do that.

>> Sure, they could have done that.

But, again, Howard, I'm not going to speculate on why they did or didn't do what they chose.

You know, our focus here is forward-looking.

How do we prevent this in the future?

I can't answer for those what occurred in the past.

Were we really focusing on the right thing?

You know, MSHA had a mantra: "End black lung."

And we support that.

But coal dust might not have really been where the focus should have been at that time.

It might have been silica rather than coal dust.

>> BERKES: For months, I had been trying to talk to the head of MSHA about the PMF epidemic and the agency's decisions to not directly address silica.

>> The MSHA mission is to prevent death, illness, and injury from mining, and promote safe and healthful workplaces for U.S. miners, a very honorable mission.

>> BERKES: David Zatezalo is a former mining company executive who runs the agency.

In September, we tracked him to a rare public appearance here at West Virginia University.

>> Silica is toxic to your body.

You hear the phrase in health circles of a "progressive massive fibrosis," these sorts of things.

To me, I believe those are all clearly silica problems.

Silica is something that has to be controlled.

(cheering and applauding) >> BERKES: I was surprised Zatezalo was so clearly connecting PMF to silica, and wanted to know why this hadn't translated into direct action.

Mr. Zatezalo, I'm Howard Berkes from National Public Radio and PBS "Frontline."

We've been interested in talking to you about progressive massive fibrosis and the epidemic of disease.

I'm wondering why you're unwilling to speak with us about that.

We've had multiple requests for interviews.

Ready to talk to you today, next week, in the past.

>> I don't think the science is that well defined on it yet, Howard.

>> BERKES: You have 2,000 miners right now with progressive massive... >> I don't think that the science of the causation is that well defined.

I don't know... >> BERKES: You said yourself that silica was... >> Could you... No, I said I suspect silica.

>> BERKES: We've interviewed dozens of coal miners and they've told us about their experiences.

They all have progressive massive fibrosis.

They're all dying from this disease.

So they've talked about their experiences.

>> Okay, I'm supposed to go up here to this picture.

>> BERKES: Why won't you talk to us about this issue?

>> Because I don't think the science is settled on it.

>> BERKES: What has that got to do with it?

You have so much experience in this field, as you just described, and you described all these deaths that are occurring.

>> Okay, let me put it this way.

I won't talk to you about it because I'm supposed to go be in a picture right now.

>> Excuse me, students are waiting for the secretary, please.

>> All right, everybody, smile on three.

One, two, three.

>> One of the things that just makes me angry is there's such a lack of urgency in the agency.

It's abundantly clear in what we're seeing.

This problem really is a silica problem and it's really why we're seeing such severe disease in miners.

So we know the problem is silica dust, yet that's not what we're protecting miners against, or our effort to protect them is utterly inadequate.

I mean, I don't know how you can reach any other conclusion.

And that is...

I mean, this is such a gross and frank example of regulatory failure.

♪ ♪ >> BERKES: Given the time it takes for disease to appear, it could be a decade or more before we know whether the new coal mine dust rules have made any difference.

>> BERKES: In the meantime, there are still more than 50,000 coal miners working nationwide.

When you come back here, do you feel, you know, pride or regret?

>> A little bit of both, honestly.

I was proud of working here.

I was a young man and I was making good money.

To sit back and look at it now, you know, they kind of molded us the way that they wanted to mold us-- buying us nice t-shirts, and tools, and hats all the time, and all these trips and stuff like that.

It wasn't worth it, you know, because... and the bonuses and all that stuff.

And we all worked our long hours and forsake our families for it.

You know, it's tough.

(voice breaking): We was all young men.

(exhales) We was just kids.

But we worked hard.

We killed ourselves here.

We have a family cemetery.

And when you already got your plot picked out at my age, that's kind of a scary thought, you know.

I hope one day I get to see my grandchildren.

I don't want to talk no more, okay?

I'm sorry.

Just give me a minute.

I'm all right.

If I can see my babies graduate from college, both of them... (sighs) ♪ ♪ (birds chirping) >> NARRATOR: Coming up next on this special edition of "Frontline"-- she's one of the few journalists to tell this story from Yemen.

>> AHMAD: The people of Yakla told me that at least seven women and ten children were killed that night.

>> NARRATOR: The extent of civilian casualties from U.S. strikes.

>> AHMAD: They were so frightened about the amount of U.S. soldiers that were sent.

There were the helicopters, the drones... >> NARRATOR: "Targeting Yemen" starts right now.

♪ ♪ ♪ ♪ >> NARRATOR: Yemen.

Journalist Safa al Ahmad has been covering the devastating war here since it began four years ago.

Now she's come to investigate a different conflict: the escalation of the U.S. fight against Al Qaeda in Yemen.

There's been little reporting from the ground about what the U.S. is doing here.

But one operation made headlines two years ago.

>> U.S. forces launched a surprise raid in Yemen overnight... >> ...targeting an Al Qaeda camp in southern Yemen on Sunday... >> ...the pre-dawn raid went wrong almost from the beginning, leaving a Navy SEAL dead.

>> A highly successful raid that will lead to many more victories in the future against our enemy.

>> AHMAD: I was hearing reports questioning how successful that mission was, and I was also hearing about civilian casualties.

I wanted to go and see for myself what had happened that night, but also what it might reveal about the larger counterterrorism operation that the U.S. were conducting.

(gun fires, explosion roars) >> NARRATOR: Yemen has been wracked by a war between armed factions since 2014.

(crowd chanting): On one side: the Houthis, a group from Northern Yemen with links to Iran.

Against them: many tribes, and a coalition including Yemeni government troops, Saudi Arabia, and the UAE, supported by the U.S. At the same time, the U.S. has been trying to target both ISIS and Al Qaeda here.

The Navy SEAL raid in January 2017 was on the village of Yakla on the front line between the tribes and the Houthis.

>> AHMAD: Since I heard about the Yakla raid, I've been trying for months to get access to the village.

I finally got a phone call-- I was going to be picked up by somebody from Yakla village and be driven there.

Yakla is a very dangerous place to get to because it sits in the middle of several front lines.

You have the Houthis, you have the tribes, and you have the Yemeni government fighting there.

You also have elements of Al Qaeda, and so this exposes everyone to the danger of U.S. drone strikes.

On the way, the driver stopped in a clearing where he told me that this is where the American Special Forces had landed.

They had trekked for seven kilometers to the village of Yakla, and so we had retraced their trip to the village.

(hammering, clattering) >> NARRATOR: The Navy SEALs attacked an Al Qaeda headquarters here, according to a Pentagon statement.

The statement said the troops met resistance, including from numerous female fighters.

One American soldier was killed and three others injured.

The military said they killed at least 14 Al Qaeda members.

>> AHMAD: I wanted to talk to the eyewitnesses that had survived the raid to hear their narrative about what happened.

ABDULILLAH AL DAHAB: >> NARRATOR: Local tribal leader Sheikh Abdulillah al Dahab has been in hiding since the raid and has not been interviewed about what happened until now.

DAHAB: >> NARRATOR: He says his tribe has been fighting the Houthis on the side backed by the United States.

DAHAB: >> NARRATOR: At 2:00 a.m., Abdulillah says his 11-year-old son Ahmed was on their roof and saw armed men approaching.

Thinking they were Houthis, the boy shouted out.

The sheikh says the commandos then shot Ahmed through the heart, and his family returned fire.

DAHAB: AHMAD and SINAN: >> AHMAD: The people of Yakla told me that at least seven women and ten children were killed that night.

The youngest was a three-month-old.

MILHA AL AMERI: >> NARRATOR: The Pentagon acknowledged that civilians, including children, were likely killed in what they called a "ferocious firefight."

But they said the Navy SEALs had obtained valuable intelligence and taken out Al Qaeda leaders-- including two of Abdulillah's brothers.

The sheikh denies the brothers had anything to do with Al Qaeda.

He says one of them, Abdul Raouf, was a tribal commander with the Yemeni army, the side backed by the U.S.

This was confirmed to "Frontline" by the Yemeni government.

DAHAB: >> NARRATOR: The sheikh acknowledges that members of his family have been connected to Al Qaeda.

>> AHMAD: The Dahab family is symbolic of the complexities of Yemeni politics.

You have people of his family who did choose to join Al Qaeda.

You have members who did not and chose to fight them.

>> NARRATOR: The sheikh's brother-in-law was Anwar al Awlaki, the Yemeni-American Al Qaeda leader who was killed in a drone strike in 2011.

Al Awlaki's eight-year-old daughter Nawar, the sheikh's niece, was killed in the Yakla raid.

The family said she was shot in the neck.

>> AHMAD: The members of the Dahab family that I spoke to told me they had paid a really high price just because they were part of the Dahab family.

>> NARRATOR: The villagers say around 30 civilians were killed.

Most are buried in this cemetery.

Department of Defense investigations later concluded that there were between four and 12 civilian casualties and and around 35 enemy combatants killed.

They would not comment on the Sheikh's brothers, and told "Frontline" they maintain "a firm commitment to protecting civilians."

♪ ♪ The Yakla raid marked the beginning of a dramatic escalation of the U.S.'s ongoing war against Al Qaeda in Yemen.

During President Obama's eight years in office, the U.S. carried out an estimated 154 drone strikes in Yemen.

In President Trump's first two years, around 176 have been reported.

>> A priority is the fight against Al Qaeda in the Arabian Peninsula.

>> This is a franchised Al Qaeda metastasizing threat.

>> This is the franchise of Al Qaeda that has demonstrated the ability to try to attack our homeland.

>> NARRATOR: The roads leading out of Yakla are littered with the wreckage of cars destroyed by drone strikes.

>> AHMAD: While I was in Yemen, I heard about a drone strike that had just recently happened.

It was in the central region of Shabwa.

It all started apparently when a boy had joined Al Qaeda.

(dog barking, Ahmad and Ali Salem speaking Arabic) AHMAD: >> NARRATOR: Ali Salem is the uncle of the boy.

He takes Safa to meet him.

For his safety, we agreed not to show his face.

He says he ran away from home with friends to join Al Qaeda.

AHMAD: BOY: AHMAD and BOY: ♪ ♪ >> NARRATOR: Al Qaeda in Yemen doesn't just preach jihad against the United States, but also against the UAE forces, Saudis, and the Houthis, all of whom they consider infidels.

>> AHMAD: The situation in Yemen is very complex right now.

You have interlocking conflicts of who is fighting who.

The people on the ground have told me that many of these young men who join Al Qaeda are joining it for local reasons, for local conflicts, and not necessarily because they want to join the global jihad.

>> NARRATOR: According to villagers in Shabwa, on January 26, 2018, the boy's father and some relatives set out by car to rescue the boy from Al Qaeda.

While driving, they came under attack.

BOY: SALEM: >> NARRATOR: The family says seven relatives were killed in the strike.

SALEM: >> NARRATOR: Ali is a soldier in the Yemeni army.

He says the boy's father was a taxi driver and two other uncles who were killed were also in the Yemeni army.

AHMAD AND SALEM: >> NARRATOR: Ali Salem prepared these papers to clear the names of his relatives.

He wants the U.S. to pay compensation for their deaths.

He says he is now the sole provider for over 30 family members.

We asked the Pentagon about the strike and Ali Salem's account of the deaths.

But they would not comment beyond a statement at the time that a strike had occurred on that day in Shabwa.

♪ ♪ In another part of Yemen, Safa traveled to the site of the largest known U.S. Special Forces ground raid in the country.

The Pentagon said at the time that seven terrorists were killed with no civilian casualties.

(animal bleating) >> AHMAD: The raid took place on a tiny little village called Athlan on May 23, 2017.

The people who lived in the village described an apocalyptic scene-- they were so frightened about the amount of U.S. soldiers that were sent.

There were the helicopters, the drones.

>> NARRATOR: The villagers say Safa is the first foreign journalist to come here since the U.S. raid.

ABU MUJAHID: AHMAD and MUJAHID: CHILD: (Abu Mo'ath speaking Arabic) CHILD: MO'ATH: CHILD: MO'ATH: CHILD: >> NARRATOR: Eight-year-old Mujahid's back and hearing was damaged in the raid.

MO'ATH and CHILD: CHILD: >> NARRATOR: A U.N. investigation later said that 50 U.S. soldiers were involved in the attack, and that in addition to the Al Qaeda casualties, five civilians were killed, including an 80-year-old man, Nasser Mahdi.

(wheel squeaking) Dhabia Ahmed was at home that night with her six children.

>> AHMED: >> NARRATOR: She says her 15-year-old son Abdullah was a conscript in the Yemeni army.

He was killed that night.

She shows his gun and says that he was just trying to defend his family, and that other men did the same.

In a statement on the incident, the Pentagon said precision airstrikes from an A.C.-130 gunship were used.

AHMED: (crying) >> NARRATOR: The villagers say the U.S. soldiers withdrew in a hurry.

They show some things the Americans left behind.

MO'ATH: >> AHMAD: While filming with the Athlan family, they brought a plastic ladder that they were struggling to open.

And they also had a medical backpack.

Within the backpack were several laminated papers.

One of the laminated papers had 22 names on it, with blood types.

I assume that they were the names of the special ops guys that were on that mission.

And it included two dogs.

>> NARRATOR: "Frontline" tracked down some of the names on the list, and confirmed they were Navy SEALs.

To protect their identities, we're obscuring the names.

The Pentagon wouldn't comment saying: "We will not discuss our tactics, techniques, and procedures."

Sources with experience in Special Forces told us even taking a list of full names on such a mission was a grave mistake.

(children chattering) SINAN: >> NARRATOR: Back in Yakla, families say they still don't understand why the U.S. attacked their village two years ago.

SINAN: >> AHMAD: The Yemenis I've spoke to in Yakla and Athlan and Shabwa, all of them have a common fear, a fear of something that is completely out of their control.

The drone strikes, the raids, adds to the massive fear and confusion the Yemenis are already feeling in the midst of this very complicated war.

>> NARRATOR: Since the Yakla raid, there have been several drone strikes around the village.

Sheikh Abdulillah's house has been hit three times; he says three of his bodyguards were killed.

He remains in hiding.

DAHAB: >> Go to pbs.org/frontline for more of Safa Al Ahmad's reporting from Yemen.

>> The human cost of this war on Yemen is frightening.

>> Then get the latest reporting on black lung from our partners at NPR and stay tuned for a special episode of our podcast, "The Frontline Dispatch," with NPR about miners with the disease.

>> It's just like turn your lungs to concrete.

>> You just stop breathing and you just wake up... (gasps) >> Connect to the "Frontline" community on Facebook, Twitter, or pbs.org/frontline.

>> ...the violent MS-13 gang for machete attacks.

>> ...police have uncovered human remains... >> If you're an MS-13 gang member, take a look behind me.

For every person here, there's ten more.

>> ...a major crackdown... >> They said, "We're taking the boy.

We're government."

>> We have seen a significant number of MS-13 gang members who entered the United States as unaccompanied minors.

>> Anyone can be labeled and cause them to be detained, and their civil rights to be violated, and these are children.

♪ ♪ >> For more on this and other "Frontline" programs, visit our website at pbs.org/frontline.

♪ ♪ "Frontline's" "Coal's Deadly Dust" and "Targeting Yemen" are available on Amazon Prime Video.

♪ ♪