NARRATOR: In Flint, Michigan...

Here's to Flint.

NARRATOR: ...officials try to save money by changing the city's water source, but instead endanger public health.

We were so sick.

WOMAN: We were experiencing hair loss.

We realized it wasn't just our home.

SIDDHARTHA ROY: People are getting poisoned because you're not treating the water right.

NARRATOR: The pipes carrying the water are corroding, leaching lead into the system, and putting thousands of children in danger.

MONA HANNA-ATTISHA: Once a child has lead in their blood, there is not much that you can do about it.

MARC EDWARDS: Even one swallow of that water would cause lead poisoning of a child.

One swallow.

NARRATOR: How did this happen?

EDWARDS: We were fighting the very agencies who were supposed to enforce the law.

NARRATOR: Can the people of Flint use science to fight back?

PROTESTOR: What do we want?

ALL: Clean water!

NARRATOR: Now, it's a massive job to make Flint safe.

McDANIEL: There's probably over 20,000 lead service lines in the city.

NARRATOR: In Flint and around the country... We've got millions of those lead pipes out there.

Might be in front of your house.

NARRATOR: "Poisoned Water."

Right now, on NOVA.

Major funding for NOVA is provided by the following.

DAYNE WALLING: This is our moment, so I think we need a countdown, from three?

ALL: Three, two, one... (mechanical whirring) WOMAN: I hear it.

(cheering, applause) All right.

Here's to Flint.

Hear, hear.

NARRATOR: With the push of a button, the city of Flint, Michigan, switches to a new source for its drinking water-- the Flint River.

That switch would soon become a disastrous combination of poisoned water and misuse of science.

GINA LUSTER: I remember the switch because it was my daughter's birthday.

It was April 25.

City and elected officials, a lot of them were saying, you know, "This is gonna save us so much money," and "This is a good thing."

And we're like, oh, boy, you know, holding our breath.

NARRATOR: There was nothing wrong with the city's old water source, Lake Huron.

So why make the switch at all?

Mainly, to save money.

CLAIRE McCLINTON: Flint is a blue-collar, industrial city.

We are the home of General Motors.

We have experienced, like other cities and areas in the Rust Belt, tremendous decline in jobs.

NARRATOR: Since the late 1950s, GM closed seven major facilities in the region.

Tens of thousands of jobs were lost.

SNYDER: We have a couple special orders this evening.

NARRATOR: In 2011, with the city close to bankruptcy, Governor Rick Snyder stripped power from city officials, and assigned a series of emergency managers to fix Flint's financial crisis.

DAYNE WALLING: An emergency manager can come into a community, take the powers of a mayor and a city council and make decisions.

We want to maintain access to a clean, sustainable water source.

NARRATOR: For decades, Flint purchased treated water at a premium price from Detroit.

Now, the emergency manager and city officials pursue a plan to save millions by building a pipeline to Lake Huron.

It would take years to finish.

Until then, the city would draw water from the Flint River, and treat it at the old Flint water plant.

There were problems from the very start.

FELIPE GATICA: Rusty water came out as soon as we turned it on.

So right then and there, you know, my wife being pregnant, she was like, "We're not gonna use the water."

McCLINTON: My clothes in the washing machine are smelling like bleach, smelling like rotten eggs.

LISA GOULD-MALISZEWSKI: We started to get rashes, listlessness, muscle aches and pains.

Where's the other piggy at?

NARRATOR: LeeAnne Walters was a stay-at-home mom with three-year-old twin boys and a teenaged daughter.

WALTERS: My hairdresser was very concerned because my hair was thinning out pretty badly, And then we started noticing it in my daughter, and in other... you know, my sons and my husband.

When we had our first bout of brown water, We didn't understand what was happening.

We were told by the city that they were winterizing the system.

But we had lived here for years at that point, we'd never experienced anything like that.

Am I hot?

You are hot.

NARRATOR: These problems led Walters to ask detailed questions about how the water was being treated.

I started requesting documents from the city.

I wanted to know about the water treatment plant, and how they were treating the water, what chemicals they were using, what their raw water data was before they treated the water.

NARRATOR: With no training in civil engineering, this was her own independent investigation.

Her first question: how does water get treated?

As LeeAnne Walters discovers, at the time of the switch, local authorities set out to treat water from the Flint River much the way any other city would.

(horn blowing) Nowhere is this better demonstrated than in Cincinnati, which has been treating river water for 200 years.

In both Flint and Cincinnati, the water starts out essentially the same: straight from the river, brown and cloudy with particles.

Now, you see the water is very cloudy, and all these particulates, things like clay, pieces of leaves, decaying sticks and things like that.

But the particles are also things like bacteria.

So we want to make sure that we remove these particles in treatment.

NARRATOR: To remove the particles, both treatment plants use a coagulant that helps particles stick together.

These bigger and heavier globs eventually sink to the bottom.

We end up with a water that's about like this.

So we actually remove about 90 to 95% of the solids in the water just through that process.

NARRATOR: To remove additional solids and bacteria, the water moves through filtration beds, containing materials like sand.

Flint's beds are smaller than Cincinnati's, but function much the same way.

SWERTFEGER: As the water trickles through the sand, the sand will remove the rest of the particulates, the rest of the pathogens that could be left in the water.

So then, when we come out of the sand filters, that water looks very clear, very clean.

NARRATOR: The water might look clean, but coming from an industrialized river, it may still carry invisible toxins.

SWERTFEGER: There are chemical manufacturers all up and down the river, and some of that material can get into the water.

NARRATOR: To remove these, many cities use carbon filtration, similar to the charcoal in an aquarium or in a home water filter.

At the end, finishing chemicals like fluoride and chlorine are added.

As a rule, river water is more difficult to treat than lake water.

MICHAEL SCHOCK: River waters are just a big engineering challenge, relative to a lake water source.

Rainwater, snow melt, runoff that goes into the river from agricultural sources.

You can get road salts.

River waters change very rapidly, and so the entire treatment plant has to be geared to respond within literally minutes to hours of big changes in chemistry.

NARRATOR: Complex chemistry and a plant that hadn't been fully operational in 50 years-- was Flint in over its head from the start?

Within a few months of the switch, not only are residents complaining of rashes and bad smells... NEWS ANCHOR: Now, back in Flint, some folks are dealing with a new problem.

NARRATOR: ...but the city is issuing public health warnings.

REPORTER: ...bacteria that prompted a boil water advisory since Friday.

REPORTER: Water needs to be boiled to kill off any bacteria.

NARRATOR: E. coli bacteria, a potentially dangerous pathogen that originates in fecal matter, is found in Flint's water.

To kill E. coli, Flint adds more and more chlorine.

We use it for household cleaning and swimming pools, but over-chlorinated water can react with organic matter and create toxic byproducts.

This starts to happen in Flint.

In October, another red flag.

ANCHOR: Concerns over water quality in Flint are leading Genesee County's biggest employer to shut off their taps.

NARRATOR: General Motors reports that Flint River water.

is corroding its engine parts.

The issue here is the levels of chlorine in the water.

It creates some sort of corrosion.

NARRATOR: GM switches back to Detroit water on its own.

Meanwhile, city officials continue to insist the water is safe.

Ten months after the switch, The Walters family is facing worsening health problems.

WALTERS: We had taken the boys in for one of their checkups.

And for being almost four years old, they seemed abnormally small to me for their age, and I was told, oh, this is normal, twins are generally smaller.

My twins weren't smaller.

My twins were seven pounds three weeks early.

So to say that this was a normal twin thing didn't sit right with me.

And the fact that every time Gavin would come in contact with the water, what it would do to his skin, and how badly he would break out.

The final straw was when they told us we had to start giving him Benadryl to take a bath.

And his skin would be so raw, he'd be so broken out, and he would scream and cry so ungodly.

We could not keep putting this child through what he was going through just to take a bath.

NARRATOR: LeeAnne Walters isn't the only one investigating Flint's water.

The city falls under the jurisdiction of the Environmental Protection Agency Region 5.

The EPA makes regulations to protect the environment, including the water supply.

Miguel Del Toral, a water regulation expert for EPA, has been following the events in Flint.

DEL TORAL: I first started to get concerned when we just had a series of events that happened one after another, beginning with the E. coli being found in the water, followed by high disinfection byproducts, and coupled with the severely discolored water.

It was obvious to me that something was really wrong there.

NARRATOR: A key component of federal water regulation is the EPA's lead and copper rule, which limits the amount of lead and copper allowed in drinking water before utilities must take action.

WALTERS: After the city came in and started testing at my home and realized that I wasn't a liar, and that I wasn't stupid, and that the discolored water was happening almost on a daily basis in my home.

My first test came back at 104 parts per billion.

NARRATOR: 104 parts per billion of lead.

WALTERS: The maximal allowed by EPA is 15 parts per billion.

NARRATOR: Later, LeeAnne Walters home will be called ground zero, known as the first critical case of dangerous lead levels in drinking water after the switch.

Walters contacts authorities in EPA Region 5, who puts her in touch with Del Toral.

DEL TORAL: I looked at the results from the Walters' home.

First result was 104 parts per billion, the second was 397 parts per billion.

But it was looked at as an isolated problem.

NARRATOR: Del Toral and Walters are right to be concerned.

Even the ancient Romans, who used lead for plumbing, knew it was toxic, though they didn't understand why.

Today, we do.

Cincinnati Children's Hospital and the University of Cincinnati have been following children exposed to lead into adulthood.

It's the longest-running study of its kind in the world.

MRI TECHNICIAN: You nervous?

PATIENT: A little bit.

A little bit?

NARRATOR: Dr. Kim Cecil is an investigator for the Cincinnati lead study.

CECIL: So, lead tricks the body into thinking it's calcium.

Whenever lead has got into your body, primarily through ingestion, it goes and hides where calcium should be, in the bones and in the cells of the brain.

Visualize a neuron.

There's the neuron that's sending the signal and then another neuron that's receiving the signal.

And typically, calcium is in that gap.

NARRATOR: Calcium is essential for neurons to communicate.

But when a child is exposed to lead, lead gets in that gap and blocks the flow of calcium.

Without calcium, synapses get weaker and brain function suffers.

CECIL: The average IQ of the Cincinnati Lead Study is 86.

It should be 100 in a typically developing population.

NARRATOR: Lead can disrupt brain growth and even lead to shrinkage or volume loss in brain tissue.

CECIL: I can give you kind of a hint of volume loss.

You can see these ventricles look plump because there's less brain.

From this analysis, I can tell you that most of that volume loss is in the frontal lobe.

And that region of the brain is responsible for what makes us the most human.

It controls our decision making, our ability to pay attention, our ability to plan, to make judgment, to evaluate rewards-- all the things that we need in life to be successful.

NARRATOR: Lead can cause harm wherever it ends up in the body.

And lead poisoning can even be passed to the next generation.

CECIL: If you're a pregnant woman exposed to lead when you were a child, that lead is stored in your bones and when your body needs calcium for the developing fetus, it's pulling lead out of the bone instead of calcium in many cases.

NARRATOR: LeeAnne Walters' drinking water has extremely high levels of lead.

But where is it coming from?

(blowing) Marc Edwards, a professor of environmental engineering at Virginia Tech...

Okay, it's not blocked.

NARRATOR: ...would play an important role in the story of Flint's water.

EDWARDS: Lead gets into drinking water almost exclusively from pipes.

There are very few cases where there's lead in water leaving the treatment plant.

NARRATOR: Edwards knows a lot can happen after the water leaves the treatment plant.

In American cities, water flows through networks of underground pipes-- first through city water mains, up to ten feet in diameter, typically made of iron.

From the mains, smaller service lines carry water to individual homes and businesses.

And in Flint, a lot of those service lines are made of lead.

EDWARDS: It used to be the law in some cities that that pipe had to be made of 100% pure lead.

And so we've got millions of those lead pipes out there around the country.

Might be in front of your house.

NARRATOR: And it's not just the service lines that can bring lead into your home.

After it goes into the house, oftentimes in the basement, there's three additional sources of lead in plumbing.

One is lead in brass, which is the faucets and brass valves.

Galvanized iron had lead in it, and then you also had lead solder, which is a glue that's used to connect metal pipes together.

So, that's how the water picks up lead right before it comes out into your glass.

NARRATOR: If there is so much lead in our plumbing, why aren't we all lead poisoned?

The answer lies in the complex chemical reactions that go on between the pipe itself and the water flowing through it.

Inside the pipe, as the water goes through, it reacts.

The chemical reactions take place with the plumbing material.

And this begins to build up kind of a protective coating, what we call a scale.

NARRATOR: This protective scale is crucial.

It becomes a barrier that prevents lead from leaching into the water.

As scientists at the EPA's Office of Research and Development reveal, this protective scale can be made of up to 90 percent lead.

SHOCK: Most people don't expect that there's actually a lot of lead in the scale.

It's not a very good joke, but we often say that you are drinking water through lead-painted straws, because these are the minerals that were in lead paint, and yet they're lining your drinking water pipe.

You're using lead to protect yourself from lead.

NARRATOR: To control pipe corrosion, water utilities often add a chemical that helps build up the scale and protect the water.

This is so critical that EPA's Lead and Copper Rule requires cities with over 50,000 people to have what's called corrosion control treatment in place.

The question is: has the city of Flint been using corrosion control?

WALTERS: I had requested from the city of Flint one of their monthly operational reports.

And I was going through that, and I was looking at what chemicals they were using in our water.

And I wasn't seeing anything that they were using for an anti-corrosion.

NARRATOR: An anxious Walters reaches out to Miguel Del Toral.

WALTERS: And so I had called Miguel.

I told him I wasn't seeing orthophosphates, anything that should say, "Hey, there's a corrosion control in here."

And so he asked me to read him the document and I did.

He asked me to read it to him again.

We went through this three or four times.

And so, he's like, "Nope, that doesn't sound right.

You need to-- can you please send that to me?"

And so, I-I emailed it to him.

And then, he called me back, and then he said, "Oh, my God, they're breaking a federal law.

They're not using any corrosion controls."

NARRATOR: On his own, Del Toral had already contacted MDEQ, the Michigan environmental agency, to see if Flint had implemented corrosion control.

DEL TORAL: Early on, we received an email from the DEQ that basically indicated that the system was... had corrosion control in place.

NARRATOR: After Walters' discovery, Del Toral emailed MDEQ to ask again about corrosion control.

The city, at that point, told us that the system did not have corrosion control in place.

I thought that was pretty incredible that they would not.

The public health implications of not having corrosion control and having lead lines in the system was-was really weighing on me at that point.

SHOCK: If you don't add a corrosion inhibitor when you should have it, the result's going to be you'll have much higher lead levels, or copper levels, or what your other metals are in that distribution system.

NARRATOR: The power of corrosion control can be seen with the naked eye.

At Virginia Tech, Amy Pruden compares Flint's water to water from the Detroit system.

She places a small iron coil-- to represent the iron water mains-- into each sample.

PRUDEN: In this case, we're going to go ahead and let this water react overnight.

And what we'll see is that, with time, the more corrosive Flint water will react with the iron.

With no corrosion control in place, the Flint water corrodes and rusts the iron much faster.

PRUDEN: And we'll also see the water begin to become orange and cloudy because of the rust.

NARRATOR: The corrosive water not only rusted Flint's iron water mains, but it also attacked the scale on the lead lines servicing individual homes.

SHOCK: So now, because this water was much more corrosive, the scale changed, it saw a different chemical environment, and the scale began to flake off and deteriorate from all types of plumbing, including the lead.

And then the lead on that surface of the pipe dissolved rapidly into the water.

(protesters chanting) NARRATOR: Over several months, protests had been building.

Built this place with my tax money!

WALTERS: We were watching people hold up bags of hair and we were experiencing hair loss.

People showing off their rashes.

We had rashes.

They were holding up jugs of water that looked not as bad as this one, but discolored.

So, at that point, we realized it wasn't just our home.

It wasn't specific to us.

And knowing that there's something happening to my children, and that my children were being harmed... You can mess with me all you want, but don't mess with my kids.

It wasn't just about my kids, though.

It was everybody's kids.

You're hurting all the kids in my neighborhood that I love, all the kids that live in the city of Flint.

And so that wasn't okay with me.

NARRATOR: 14 months after the switch, Miguel Del Toral's emails reveal frustration at what he sees as his own agency's unwillingness to take charge of the growing crisis.

He does something that catches EPA Region 5 leadership by surprise.

He writes a preliminary report on the situation in Flint, sharing it with LeeAnne Walters, who gives it to the press.

EDWARDS: The memo laid out the danger to Flint's residents and children: that they were not being protected by federal corrosion control laws.

There was one child who'd been lead poisoned, and, in all likelihood, there were many others.

NARRATOR: But the memo fails to inspire the kind of action Flint residents are looking for.

BRAD WURFEL: Anyone who is concerned about lead in the drinking water in Flint can relax.

NARRATOR: EPA Region 5 director Susan Hedman apologizes to Flint's mayor for its release.

EDWARDS: Then, the mayor of Flint went on TV drinking the water, telling everyone in Flint the water was safe to drink.

NARRATOR: Later, according to NPR, a spokesperson for the Michigan Department of Environmental Quality, MDEQ, will describe Del Toral as a "rogue employee."

And according to LeeAnne Walters, another MDEQ official discredits his report.

WALTERS: Liane Shekter Smith, the head of drinking water for MDEQ, told me that Miguel had been handled, that his report was flawed, and there would be no final report.

NARRATOR: By now, Walters' son, Gavin, has been diagnosed with lead poisoning.

WALTERS: Well, I had called Marc in tears-- I was just bawling my eyes out-- and I'm like, "What do we do?

How do we stop this?

"We just can't sit by and let all these kids be poisoned.

"It's too late for my family.

What about everybody else's kids?"

NARRATOR: Edwards was already working with Walters to measure the level of lead in her water.

EDWARDS: I'll never forget calling her on the phone and telling her how to fill up 30 bottles.

And so she was at this sink here, filling up the bottles and she Federal Expressed the samples back to us and it took us a few days to analyze them.

When I got those results, it was about midnight.

I was in my easy chair and I almost-- I almost fell out of it and, I mean, my heart skipped a couple of beats because it-it was the worst lead and water contamination I'd seen in 25 years.

NARRATOR: Virginia Tech researcher Jeffrey Parks evaluates the water samples from the Walters' home.

(device whirring) PARKS: What we found was that there was a lot of lead everywhere, for the most part.

The first sample was over 2,000.

And as we flip to sample 20, which is 20 liters of water being flushed through her kitchen sink, that sampled with 13,200 parts per billion of lead.

5,000 is considered hazardous waste, so we're almost three times the level of hazardous waste in that one sample.

NARRATOR: Poisoned water.

Poisoned science.

Government inaction.

Lives of children and families under threat.

To Marc Edwards, the story unfolding in Flint is all too familiar.

EDWARDS: I knew something like Flint was inevitable, based on ten years prior experience in Washington D.C. REPORTER: For the residents of the nation's capital tonight, there was a concern over a potential danger at home.

EDWARDS: From 2001 to 2010, they suffered the worst lead contamination event in modern U.S. history.

NARRATOR: The water crisis in the nation's capital started in the early 2000s when the D.C. Water and Sewer Authority, WASA, and the Army Corps of Engineers made a water treatment switch.

And, like Flint, they failed to add corrosion control chemicals to the water.

CAROL SCHWARTZ: WASA apparently has uncovered elevated levels of lead in D.C. tap water and, apparently, has been aware for some time that the problem could be widespread.

We want to know what actually happened.

EDWARDS: Congress was mad because lead was high.

People were marching in the streets.

They were out of their mind with anger.

NARRATOR: D.C. residents had been drinking lead-contaminated water for almost three years before the public was notified.

Elin Betanzo was a water engineer at the EPA.

Even though we have a drinking water regulation that directly addresses lead in drinking water, the Lead and Copper Rule, my boss asked me, "Do you think people were actually hurt here?

"We need to find out if children get poisoned by lead through drinking water."

NARRATOR: Betanzo began her research but never completed it.

BETANZO: I was given a leadership role on a different project.

But sometimes when I look back on it, I wonder if I was moved because I was asking too many questions about what was happening in Washington D.C. NARRATOR: Then, in 2004, the Centers for Disease Control reported that children in D.C. who had been drinking the contaminated water did not have high enough levels of lead in their blood to cause concern.

EDWARDS: The claim was that kids could drink any amount of lead in water and it wouldn't hurt them.

And that story spread nationally, internationally, did all kinds of harm to kids.

That's the danger of bad science.

NARRATOR: Edwards challenged the CDC's findings.

And over the next six years, spent thousands of dollars of his own funds and demanded scores of documents under the Freedom of Information Act.

It's not so much the initial crime.

It's when people read these papers and believe it, act on it, and then you had cheating all around the country because it didn't matter how much lead in water your kid drank.

NARRATOR: Edwards discovered that thousands of blood test results had been lost.

And many of the individuals tested were already drinking filtered or bottled water.

A congressional investigation agreed.

There were grave problems with the scientific integrity of the study.

I was just horrified that, you know, finally, there is confirmation that everything that had been shared between 2004 and 2010 was wrong.

And part of me felt like I should've been able to see that and intervened.

NARRATOR: Marc Edwards estimated that more than 40,000 children under the age of two or in the womb were potentially exposed to high levels of lead in the water.

Many could be left with lifelong problems.

The experience had a huge impact on him.

EDWARDS: You're questioning these agencies.

And to see them attack you, and to see your friends leave you and your career destroyed, but the public welfare depends on you getting the truth out.

NARRATOR: Over a decade after the D.C. crisis, Siddhartha Roy, a PhD student of Edwards, knows how affected he was by the ordeal.

ROY: It radicalized him.

So, that kind of gave him a playbook, a set of tools that we were ready to deploy in case another D.C. happened.

NARRATOR: To Edwards, Flint is the next D.C.. EDWARDS: All the science was done essentially before I got involved.

LeeAnne was the one who figured out that her children had been poisoned by the water.

LeeAnne figured out on her own that the state had actually said that corrosion control was in place when it wasn't there.

And Miguel had checked into it and found out it was all true.

We were mainly involved in figuring out just how bad the problem was getting.

NARRATOR: Edwards hopes a city-wide investigation of Flint's water will force government agencies to finally take action.

And for that his playbook calls for willing bodies.

EDWARDS: We needed a team of students to immediately go to Flint and start sampling the water.

So, the key to getting students to do their job is to feed them free pizza.

EDWARDS: I sent out an email requesting volunteers and I used the bribe of free pizza.

(laughs) And I explained the situation that I felt this entire city's future was in danger.

ROY: He was going to launch a volunteer effort and he asked if people were willing to volunteer.

So, we said yes.

EDWARDS: It was us or nobody.

This was a war.

NARRATOR: Marc and his students drive 550 miles from Blacksburg, Virginia, to Flint to test the water and distribute sampling kits.

Flint residents will have to follow a rigorous scientific protocol for the results to be valid.

EDWARDS: What are you up to, 80?

WOMAN: 85, yeah.

MAN: Sort of 90 something.

Okay, well, only 200 more to go.

ROY: We wanted to make sure every resident gets how to actually sample, uh, their homes.

After you have timed it for 45 seconds, at 45 seconds, fill this up.

I made sure that there were 45 participants in each zip code so we made this a statistical test, so we could prove that this was a citywide problem, not specific to one home or one zip code.

We were given 300 kits.

I'm here for the water kit.

And within those 300 kits, we returned 277 kits in three weeks.

You have a great day.

Citizens testing their own water to prove that there's a problem, no one's ever done anything like that before.

ROY: The people of Flint really were desperate for answers.

LUSTER: We were so sick.

I mean, like, missing numerous days of work and school and we did not know what the heck was wrong with us.

I mean, just, severe fatigue and diarrhea and rashes and losing teeth and hair.

And we were going to doctors and no one had an answer.

PROTESTOR: I had to go in and pay a $512 water bill for water that is making my family sick.

ROY: They had been protesting this water quality and they were not getting anywhere.

The city insisted everything was fine.

NARRATOR: By early September 2015, 17 months after the switch, this experiment in citizen science is yielding results.

Hundreds of samples are collected by residents.

When analyzed by Virginia Tech, many show high lead levels, some six times higher than the Lead and Copper Rule allows.

Students begin calling homes with the highest lead levels to warn residents not to use tap water without a filter.

An effective filter can remove up to 99% of lead and other metals.

I called up this woman who had very high lead and she asks us, "So, how much does a filter cost?"

And we're like, "It's $25."

And she goes, "Well, I'm on social welfare.

"There's no way I can afford $25... ...in the next two months."

I've never felt so helpless in my life.

MOORE: Let's call this what it is.

It's a genocide.

It's not just a water crisis.

It's a genocide.

It's a racial crisis.

It's a genocide.

It's a poverty crisis.

MAN: That's right.

(chanting): Water is a human right.

Fight, fight, fight!

EDWARDS: We realized early on that we had to be investigative scientists.

NARRATOR: Edwards has another rule in his playbook.

Get hold of internal government documents to see what's happening behind the scenes.

We knew what documents to ask for.

We, and we alone, knew where the bodies were gonna be buried.

ROY: Unknown to all of us, Marc was filing Freedom of Information Act requests left and right.

NARRATOR: On September 15, 2015, Virginia Tech researchers publicly present their findings.

Flint's water has dangerously high levels of lead.

We estimate that the water in about 5,000 Flint homes is over standards set by the World Health Organization for lead in water.

This evidence shows that Flint is not monitoring according to the Lead and Copper Rules given by the EPA.

Basically, the bottom line is, stop trying to come up with ways to hide the lead.

Yeah.

Amen.

You should be looking for the high lead, that is your job as the DEQ.

That's right.

(crowd applauds) ROY: We left a very clear message that no matter what the state says, no matter what the city says, the science is clear on this and no one should be drinking that water.

NARRATOR: But Michigan authorities at MDEQ dispute Virginia Tech's findings.

ROY: MDEQ says that the VT research group led by Marc Edwards, they essentially can go to any city and they'll find lead.

Uh, essentially, they pull the lead rabbit out of the hat.

EDWARDS: Why is it that normal people sampling their water are finding all this lead, when the city and state who are being paid to do this and determine if the water is safe, can't seem to find any lead?

NARRATOR: The answer would be found in the emails and documents streaming in from Freedom of Information Act requests.

When the Virginia Tech team and other investigators scour the documents, they uncover disturbing problems with the state's testing protocols.

EDWARDS: And so, when it came to Flint, they used every trick in the book.

They used precleaning of pipes the night before sampling.

They told consumers to clean out their lines for five minutes.

DEL TORAL: By including an instruction for residents to preflush the tap before they collect compliance samples, what that in effect does is results in less lead being captured than is actually there.

And so it makes the public water system look like they have low lead levels when, in fact, they may not.

EDWARDS: On top of that, incredibly, they had samples from LeeAnne Walters' house.

All of those samples were thrown into the garbage.

They said that LeeAnne's house was not an approved sampling site and therefore, they weren't gonna count any of those samples.

And I am in shock again.

I am witnessing engineers trying to artificially reduce the actual numbers by manipulating where you sample.

NARRATOR: But a week later, new evidence emerges that authorities cannot ignore.

It begins with water engineer Elin Betanzo, who'd been at the EPA during the D.C. crisis.

By coincidence, she is now working in southeast Michigan and reading about the crisis in Flint.

BETANZO: I had seen a news report where there is a memo written by Miguel Del Toral from the EPA Region 5 office.

And I used to work with Miguel.

I have so much respect for Miguel.

And so when I saw his name on this memo, and I read it and I understood it, I was scared.

I was scared for the people of Flint.

(children talking indistinctly) BETANZO: So, I thought back to Washington D.C. and I thought about what happened there.

I was thinking, "I know what's happening here.

What can I do?"

NARRATOR: A few weeks later, Betanzo is at dinner with her friend Dr. Mona Hanna-Attisha, a pediatrician with access to crucial blood data at Flint's Hurley Children's Hospital.

BETANZO: So then, like, my brain is spinning, and I said, "Do you have access to all the medical records "at your hospital?

"You've got to do a study.

"You've got to look to see "if lead levels in children's blood has increased from before they switched the water."

She got started on her study the next day.

HANNA-ATTISHA: That night was the first night that I stopped sleeping, because anybody who knows anything about lead stops sleeping.

And that really kind of started my, almost, crusade to find out if that lead in the water was getting into the bodies of our children.

This is not something you mess around with.

We are never, ever, ever supposed to expose a child to lead because once a child has it in their blood, there is not much that you can do about it.

Dr. Hanna-Attisha begins a systematic study of the amounts of lead in children's blood.

How old are you?

Four.

You are doing real good.

HANNA-ATTISHA: So what we did is we compared lead levels before the water switch in 2013, and we compared them to lead levels after the water switch in 2015.

We were really only looking at one thing, was the percentage of children with lead levels at or above five micrograms per deciliter.

When we saw the results, we weren't surprised, but we were heartbroken.

How could this have happened?

We saw that the percentage of children with elevated lead levels, this-this five or greater, had doubled after the water switch.

And in some neighborhoods where, where the water lead levels done by Marc Edwards were the highest, were the same neighborhoods that the children's blood lead levels had increased the most.

But, right away, the state's machinery began to dismiss me.

They began to dismiss the research, and that the state's numbers didn't add up to my numbers.

They said it was causing near hysteria.

I shouldn't have been surprised because, for 18 months, the people of Flint were dismissed, and the moms were dismissed, and the activists were dismissed, and the pastors, and the journalists, and the EPA scientists were dismissed.

NARRATOR: But a week later, Dr. Eden Wells, chief medical executive at Michigan's Department of Health, concludes the research is sound.

She is pivotal in convincing other agencies of the importance of this study.

WELLS: Do we know how many children will actually have a long-term effect from this exposure?

We do not.

PROTESTERS: What do we want?

Clean water!

When do we want it?

Now!

MAN: There are babies that are sick that will have to deal with illnesses for the rest of their life.

You have people that are in hospitals for multiple months, while politicians are sitting back playing politics.

(chanting) NARRATOR: And lead is not the only danger in Flint's waters.

RACHEL MADDOW: A deadly spike in something called Legionnaires' disease.

NARRATOR: During the crisis, Flint suffers one of the largest outbreaks in U.S. history of Legionnaires' disease... REPORTER: State health officials say the number of deaths from Legionnaires' disease... NARRATOR: ...One of the deadliest water-borne illnesses in the developed world.

It's a severe form of pneumonia caused by legionella bacteria.

Experts suspect that the legionella outbreak was triggered by Flint's water treatment.

To our knowledge, what happened in Flint is really the first example of where lack of corrosion control can trigger a Legionnaires' disease outbreak.

NARRATOR: According to Amy Pruden and Marc Edwards, chlorine added to Flint's water should have killed off legionella.

But without corrosion control, Flint's water filled up with rusty iron.

Chlorine reacted with the rust and was used up.

And with no chlorine to stop it, legionella thrived inside Flint's water pipes.

90 people were infected.

12 of them died.

In October 2015, 18 months after the switch, Flint finally changes back to the Detroit water system and once again receives properly treated water from Lake Huron.

But it will take many months for Flint's water pipes to rebuild the protective scale that's been stripped away.

The Virginia Tech study concludes that over 40% of Flint homes had elevated levels of lead in their water and as many as 8,000 children under the age of six were exposed.

WALLING: A rise in the number of children with elevated blood lead levels was devastating for our community.

NARRATOR: Crucial evidence from Freedom of Information Act filings by Marc Edwards, the ACLU, and others reveals the failure of Michigan's water and health officials to protect the public.

13 criminal indictments follow, including emergency managers and officials from Michigan's Department of Environmental Quality, Department of Health and Human Services, and the Flint Water Plant.

Flint was a casualty of arrogance, absence of accountability, shirking responsibility.

NARRATOR: Charges include tampering with evidence, conspiracy and willful neglect of duty.

Susan Hedman, head of EPA Region 5, resigns under criticism.

WALLING: One of the emails from the EPA said, "Is Flint the kind of community that we should go to bat for?"

And, you know, I just felt sick to my stomach to think that, you know, my family, my neighborhood, my city somehow counts less?

Testimony you will give will be the truth, the whole truth, and nothing but the truth.

WALLING: And then, later, the state Department of Environmental Quality admits that they had misinterpreted the Lead and Copper Rule, that the orthophosphate should've been ordered from the beginning.

Corrosion treatment should've been required by the Department of Environmental Quality... That's not how government's supposed to work.

Uh, it's not how science is supposed to work.

NARRATOR: Mayor Dayne Walling-- who drank the water on TV during the crisis-- is voted out of office.

Over a year and a half after the switch, officials declare a state of emergency.

So far, federal and state agencies have provided over $300 million to help the city.

But some estimate that as much as $1.5 billion will be needed to upgrade the water system and provide services for families and children affected by the crisis.

For now, bottled water is a way of life.

CHERKEETHA LOVE: We're passing out water for the residents of Flint.

For us.

We all need the water because we have lead and different things going on with our water.

16, 18.

WALTERS: I tell people, if they don't believe Flint is that bad, turn off the water to your house, go in your basement or wherever your shutoff is, turn it off for the entire week and-and see how it is to live.

My children will never drink water from a tap ever again.

My family will never, ever, ever trust a water source again just because we're told to.

LUSTER: I mean, the amount of water bottles just my small family goes through would shock the average person.

Easily, you can go through a case of water just with one dinner.

We didn't think we would be living years like that.

We thought this would be over.

When they did that switch, they did it for financial...?

Yeah, it was financial.

NARRATOR: Gina Luster's father is a water distribution specialist helping to replace pipes in Flint.

VEO: Two of the grandchildren had exceedingly high levels.

The youngest one is just, what, eight now, so she's been drinking it, you know... She don't know any other water system, you know?

NARRATOR: Flint is now working to replace about 20,000 service lines.

But how many more Flints are out there?

A report estimates that over 18 million Americans were served by water systems in violation of the Lead and Copper Rule in 2015.

MICHAEL McDANIEL: This is gonna happen over and over again.

We're seeing it here, we're gonna see it across the rest of the country.

Any older industrial city where you've got older service lines and older mains that have been there for 80, 90 years, if we aren't replacing those on a regular basis, you're gonna have the same problems here.

SCHOCK: It's going to take time.

There are, you know, literally millions of pipes.

We don't know how many lead pipes there are, but it's many millions.

This is going to take decades and decades to do.

The interim solution is we need stringent corrosion control and very proactive monitoring.

NARRATOR: Some of the same agencies criticized during the crisis are now supporting the work to heal Flint.

EDWARDS: I saw how hard EPA and MDEQ worked to help get Flint fixed since January of 2016.

It's been amazing.

NARRATOR: Today, Marc Edwards and local authorities agree that the water in Flint is safe to drink with a filter.

VEO: I get emotional when I think about the kids.

And, um...

Uh, excuse me for a minute.

(exhales) But, you know, as a licensed water professional in the state of Michigan, you see, you read about, you hear about, you talk about the long-term effects of the bacteria, the heavy metals, the lead-- you know what it can do.

And... and you just hope, by the grace of God, that the people are okay.

DEL TORAL: From the standpoint of science, once you start to corrupt the science, the validity of the results that you're trying to present get called into question.

If you corrupt the science, in a sense, you corrupt your agency.

And once the public loses trust, it's gonna be very difficult to try to regain that trust and may take a long time.

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