All language subtitles for Fatal.Engineering.S01E03.1080p.WEB.h264-FREQUENCY_track3_[eng]

[narrator] Water is the source
of all life on our planet.

Over thousands of years,
humans sought ingenious ways

to control and store it,
with one method above all else

representing a towering symbol
of that ingenuity...

the dam.

[Dr. Shini]
More than just a vast wall

of steel and concrete,
the dam is an essential tool

in human survival.

But dams can be deadly.

Brazil, 2019.

Millions of tons
of toxic sludge were unleashed,

when the walls
of a dam gave way.

The result was a devastating
environmental disaster

that claimed the lives
of 270 workers

and anyone unfortunate enough
to be in its path.

[Daniel] If you're
underneath the dam,

it looks like the entire
surface of the earth

has detached and is now
rushing towards you.

[thunder crashing]

In September 2023,

an estimated 24,000 people lost
their lives in the Libyan city

of Derna, when not one,
but two dams collapsed.

[Dr. Shini]
A 30-foot-high wall of water

slams into the city below.

In 1959, 423 people
on France's southern coast died

when a newly
built dam collapsed,

flattening villages and a town.

[Rob] Nobody knew at the time,

but the location was right
across a geological fault line.

With an estimated 60,000 large
dams in operation worldwide,

have engineers truly learned
the lessons of the past?

[indistinct chatter]

Or is the clock quietly ticking
down to the next example

of fatal engineering?

[theme music playing]

[menacing tones playing]

We are on the French Riviera.

A unique coastline
boasts the clear blue waters

of the Mediterranean
and rugged hills,

known for their raw,
untamed beauty.

But since 1959, the region
has carried a permanent scar,

a name that still haunts
its people to this day --

Malpasset.

The circumstances over
a number of years

have all conspired
to this one moment in time.

[water rumbling]

It's 9:13 PM, on Wednesday,
December 2, 1959,

when the unthinkable happens.

The Malpasset Dam, holding back

50 billion cubic meters
of water,

the equivalent of 20 million
Olympic swimming pools,

collapses without warning.

[water roars]

The entire dam unpeels
from right to left,

unleashing all of the water,

dumps it straight
into the valley.

[water roaring]

The rupture unleashes
a 40-meter-high wave,

the height
of a 13-story building.

600-tons sections
of the dam's walls are hurled

hundreds of meters away
like pebbles,

obliterating everything
in their path.

[powerful music playing]

At an estimated speed
of 43 miles per hour,

the water charges downriver,
almost instantly destroying

the two small villages.

[Daniel] The water then barrels
further down the valley

towards the town of Fréjus.

[menacing music playing]

9:33 PM.

Just 20 minutes after
the collapse, the wall of water

reaches the town of Fréjus,
home to 13,000 people.

Still three meters tall,
the water is now littered

with debris and concrete,
making it all the more deadly.

This relentless force floods
the western part of the city,

taking only five
minutes to wash away

30 kilometers
of railway tracks.

[menacing music continues]

10:00 PM.

Nearly 45 minutes
after the disaster begins,

the raging torrent finally
reaches the Mediterranean Sea.

The next morning,
survivors awaken to horror.

[Dr. Shini] But most tragically,

approximately 423 people
lost their lives,

although the true figure
could have been much higher.

Why did a dam built of concrete
and steel fail so suddenly?

We are in the late 1940s
in Southern France,

in the city of Fréjus.

Regular droughts during
the long, hot summers

severely impact
this growing city,

and local farmworkers struggle
to make a living

from the arid land.

[Dr. Shini] What they all needed
was a regulated flow of water,

a steady and reliable supply
for agriculture,

domestic use, and as a center
for booming tourism.

[Rob] It was decided that a dam
should be built to control

the rainfall and control
the flow of water.

[Daniel] And so surveys were
done looking for the best place

to put a large dam to control
these seasonal flooding events

that would happen.

Experts identify a narrow gorge
in the Reyran Valley,

located 12 kilometers
upstream from Fréjus.

It's the work
of French engineer André Coyne.

With 70 dams to his name,
his work was widely respected.

Standing 66 meters high,
the equivalent

of a 22-story building,
and 222 meters long,

the Malpasset Dam
is made of concrete and steel.

With a solid
masonry foundation,

it measures 6.78 meters wide
at the base

and 1.5 meters thick
at the top.

[Daniel] He chose
a double arch dam.

And this dam is very unique
and very well suited

because it minimizes
the material

while maximizing its strength.

Built to hold 50 billion
cubic meters of water

stored in the reservoir
behind it,

the upstream facing
curved design

distributes the immense
weight of the water

along the structure
and onto the opposing banks.

Control valves at the base
of the wall

and a spillway at its center

are designed
to release water and prevent

excessive pressure buildup
on the dam.

For centuries,
arch dams have been a proven

and tested design,

but they must be built
in the right location.

[Daniel The selection was more
based on the size

and shape of the valley,

and not so much
about the underlying geology.

Nobody knew at the time,
but the location

where the Malpasset Dam
was built

was right across
a geological fault line.

Where you have a fault line,
you have bedrock that moves,

maybe moves imperceivably
to the human eye,

but it moves all the same.

And if you build something
on top of that rock,

if your foundations move,
your structure will also move,

and movement is not a word that
you associate with a dam wall.

In their rush to construct it,

André Coyne and his team
of engineers

failed to fully
assess the risks

posed by the terrain
beneath the dam.

This oversight doomed
the Malpasset Dam

from the moment
of its construction

and would set off
a catastrophic chain of events

for the valley's
residents below.

The decision to ignore it

would be the first
fatal mistake.

Celebrated as a marvel
of construction

at its inauguration in 1954,

the Malpasset Dam
was destined for failure.

But is this engineering error
the only factor responsible

for the terrible disaster?

[Daniel] Usually,
when you construct a dam,

proper procedure to test
its mechanical robustness

is to fill a little bit,
drain, look for leaks,

fill a little bit more,
this incremental

and repeated filling.

[Rob] And you can let it do
its job for decades to come.

That didn't happen at Malpasset.

The Reyran River,
which feeds the Malpasset Dam,

is dry for nine months
of the year,

limiting the ability to fill
the reservoir incrementally

and test the dam.

And so, in this case,
it was never really tested

until it was
at its full capacity,

and the problems that existed

weren't known until
it was completely full.

It takes five years
for the reservoir

to reach full capacity,
but during this time,

as the dam slowly fills,
water begins seeping

into the geological fault
beneath the structure.

The pressure exerted
by the reservoir increases

as the water level rises,

forcing water deeper
into the fault.

[water babbles]

[Rob]
The pressure where that water
was entering the bedrock cracks

pushing the water ever further,

splitting the rocks ever more.
It's a chain reaction.

In November 1959, one month
before the collapse,

with the water level still
seven meters below the top,

small cracks begin to appear
on the dam's wall.

Considered minor leaks,
they are ignored by engineers,

convinced that the design is
strong enough

to withstand these anomalies.

But there's more...

[water roaring]

[thunder crashing]

A new factor further
accelerates the tragic fate

of the Malpasset Dam.

[thunder crashing]

There is a huge storm
that is dumping

a tremendous amount
of water down onto the earth.

[rain hissing]

The reservoir fills rapidly.

The dam's caretaker
requests permission

to open a control valve
at the base of the wall

to release water
and reduce pressure

from the rising levels.

-[water gushing]
-[thunder crashing]

[menacing music playing]

His request is denied.

Because just downstream,

there's a huge highway
construction project,

this massive A8 highway
that will connect

the regions of Southern France.

And the concern is this
uncontrolled release of water

will obliterate
the construction site.

[thunder crashing]

5:30 PM.

For the first time, the dam
reaches maximum capacity.

It now has to withstand
the pressure

of 50 million
cubic meters of water,

enough to fill 20,000
Olympic swimming pools.

[rain hissing loudly]

As the heavy rain continues
to pour, the dam's engineer,

André Coyne, arrives on site
to inspect his structure.

Aware of the risks
threatening the dam,

he finally orders the control
valves to be opened.

It's 6:00 PM

He doesn't know it yet,
but it's already too late.

The damage has been done.

[Dr. Shini]
Downstream, thousands
of residents from several

small villages
and those in the town of Fréjus

are blissfully unaware
that a now unstoppable

chain of events has begun

that would ultimately
destroy their world.

9:00 PM.

Despite warnings that the dam
was in danger of bursting,

the local authorities had not
issued any orders to evacuate

the town and surrounding area.

One final and disastrous factor
would then come into play...

[intense music builds]

The A8 motorway construction,
just a kilometer downstream

from the dam, a project that
had been underway for months.

[Dr. Shini] While on site,
engineers are aware of the dam,

but confident their construction
works would do nothing

to affect the stability
of the dam wall.

However, one crucial and fatal
decision changed everything --

the use of dynamite.

[explosion blasting]

Blasting is a common
construction technique

used to break up
extremely hard mountain rock.

However, the detonations
create shock waves

that reverberate
through the ground.

That blasting

is only gonna exacerbate

whatever existing
problems happen.

Each blast sends
violent shockwaves

towards the fault line.

[Dr. Shini] What had been small
but acceptable cracks

in the immense wall has now
turned into large streams

of water running down
the right side of the structure.

With the unstable bedrock,
the increasing amount

of pressure on the water
making its way into the cracks,

and the explosions occurring
just a kilometer away...

[explosion blasts]

...all the pieces
of this disastrous jigsaw

are now in place.

9:13 PM.

The dam, once a symbol
of modern engineering,

collapses under the pressure.

[rumbling]

The collapse begins
with the right-hand side

failing first, spreading quickly
from right to left.

And as you're
looking up at the giant wall,

huge chunks of steel-reinforced
concrete break away

from the dam, releasing
a 40-meter-high wall of water

down into the valley.

The raging water destroys
everything in its path

at an estimated speed
of 70 kilometers per hour.

[melancholic music playing]

A five-kilometer stretch
of the Reyran Valley

is literally wiped out.

The town of Fréjus is pummeled.

155 buildings are completely
destroyed and 796 are damaged.

But the most tragic loss
was the human toll.

Although the actual number
may be higher,

423 people perish
when the Malpasset Dam bursts.

[Daniel] The lessons
that can be learned

are that it pays

to do your homework
at the beginning, right?

The dam selection criteria --
where is it

and what is the underlying
geology is most important,

because if you get that wrong,
it doesn't matter

how fancy your dam is,

you are building
it on shaky ground.

A poor site selection
and bad construction practices

were enough to doom
the structure from the start,

making the Malpasset Dam
collapse

the worst dam
disaster in France.

But what happens
when dams that are not made

of steel and concrete collapse?

[enigmatic music playing]

11th of September, 2023,
the day when the city of Derna,

on the Mediterranean
coast of Libya,

is put on the map...

but for all the wrong reasons.

[thunder crashing]

It's 1:00 AM.

13 kilometers away,
the Al-Bilad Dam has burst,

sending a terrifying
wall of water

towards the country's 18th most
populous city.

All that remains between
their safety and the total

disaster heading their way
is a second larger dam.

Located on the outskirts
of the city,

the Abu Mansour Dam
is much larger than the first.

It serves as a shield
for Derna's 100,000 inhabitants

in the event of flooding,

and is intended to be able
to contain the hellish flood

heading their way.

Tragically, the pressure
is too great.

The entirety of Derna is asleep,
and so they are unaware

of this catastrophe
which is about to happen.

[water gushing]

This second dam offers little
resistance to the gigantic,

overpowering wave.
It's now 3:00 AM.

[Dr. Shini] In a deafening roar,
the dam collapses.

[Daniel] All of that water is
now released into Derna,

Buildings are no match
for the destructive power

of water and mud.

[transformer blowing]

The power goes out, plunging
the city into darkness.

Residents scramble
to safety on rooftops.

[menacing music continues]

As day breaks
the following morning,

the true extent
of the devastation can be seen.

The city looks like a war zone.

[rescuer yells indistinctly]

[speaking in Arabic]

Although the official
death toll is 5,923,

this fatal wall of water
was estimated to have actually

claimed the lives
of 24,000 people,

a quarter
of the city's population.

It was the second deadliest
dam burst in history.

What meteorological
and technological phenomena

turned these monumental civil
engineering structures

into fatal engineering?

[tape whirring backwards]

[menacing music playing]

[Rob] That region
had experienced

violent Mediterranean
storms in the past --

in the forties, the fifties,
and in the sixties.

They weren't protected
from the environment,

and so it necessitated,
at the time,

some amount of water control.

It was decided
that a dam was the right piece

of infrastructure to protect
the city of Derna,

but not just one dam,
a series of two dams.

Built in the 1970s, by a then
Yugoslavian company,

the first dam is located
upstream of the Derna River,

Its reservoir can hold
1.5 million cubic meters,

equivalent to the volume of 600
Olympic-sized swimming pools.

[Rob] The Al-Bilad Dam would be
a smaller structure to contain

rainwater and slow any flow
coming through the valley

towards the city.

[Daniel] It would augment
the ability of the first dam,

the main dam,
to control the floodwaters.

The Abu Mansour Dam is located
on the outskirts of the city,

just a few hundred meters
from its edges.

At 75 meters high, it can hold
22.5 million cubic meters,

15 times more
than the Al-Bilad Dam.

The second dam,
the Abu Mansour Dam,

would be much bigger,
as almost a backstop

to the first dam --
working together...

the city of Derna
would be protected

from even the worst storm...

or so it was thought.

[thunder crashing]

Here, in Libya, it was decided

that an embankment dam
would be built.

Low-cost and easy to construct
in this arid area,

an embankment dam uses
a gravity-based design

that relies on its own mass
to hold back water.

The Al-Bilad and Abu Mansour
dams consist of two main parts,

a central core constructed
of large blocks of concrete

and rocks, which is then filled
with clay to reinforce it,

creating an impermeable wall.

It's covered
with an outer layer

of more natural materials,
such as earth,

sand, and pebbles,
which can be sourced locally.

Since it is just
natural material,

the environment eats away at it
more easily than

a more rub and bust material
like concrete.

It's not sophisticated.
It's just dirt, right?

And so the effect of water
on that can be catastrophic

if it's not done well.

When the Al-Bilad Dam
was built,

it seemed to be
an appropriate choice

for the volume of water
needed to be held

to safely control the seasonal
floods that, in the past,

had caused so much damage
to the city of Derna.

[thunder crashing]

[Dr. Shini]
This was back in 1970.

What the engineers couldn't
have predicted back then,

and therefore hadn't taken
into account, would be

the devastating and unstoppable
effects of climate change.

At the beginning
of September 2023,

Storm Daniel wreaked havoc
in the Mediterranean Sea.

It caused more
than two billion US dollars

in damages in Greece and Turkey

before moving toward
the North African coast.

[thunder crashing]

On the morning of September 10,
rain, estimated at 250 times

the average monthly amount,
fell in just 24 hours.

The authorities declared
a state of emergency

as unprecedented rainfall
poured more and more water

into the Derna Valley
upstream of the city.

What was normally
a dry riverbed,

now resembled a surging flood.

[Daniel] The only thing
in between Derna

and that massive amount of water
are the dams, damming the river.

It's 12:30 AM and Storm Daniel
has been raging,

as unprecedented rainfall
poured more and more water

into the Derna Valley
upstream of the city.

The water rushes into the
reservoir of the Al-Bilad Dam.

Like all dams, it is equipped
with safety mechanisms called

spillways that are designed
to release excess water.

The spillway is built lower
than the desired maximum level

of the reservoir.

When the water
reaches its level,

it begins to overflow
into the spillway,

allowing the water to be
diverted in a controlled manner

to the other side of the dam,
preventing the water level

from rising dangerously.

But in this case,
there's just so much water

that the spillways
can't take up that volume.

It's 12:55 AM.

The reservoir level quickly
reaches its maximum capacity.

At this point,
a devastating phenomenon occurs

that will trigger
the carnage to come.

There's a mechanism
which is called overtopping,

which is extremely bad for dams,
in earthen dams in particular.

Overtopping is when the water
that exceeds the dam walls

begins to cascade over
the opposite side of the wall.

[Daniel] The water
that's overtopping the dam

isn't going very quickly,

but it's falling
a long distance.

And so, with that distance,
there's a lot of kinetic energy

that's being imparted into
the dam, this earthen dam --

it's not gonna stand up
to that abuse,

and so it just erodes.

When the overtopping
of an embankment dam

like Al-Bilad begins,
the loose materials,

especially earth
and clay components,

are quickly washed away.

And if the structure is old
and not properly maintained,

the effect is compounded.

Such is the case
with the Al-Bilad Dam.

It's 1:00 AM.

The pressure is too much,
and the Al-Bilad Dam completely

completely gives way to
the unstoppable force behind it.

-[concrete crashing]
-[water roaring]

The only thing standing
in between Derna and the huge

amount of water that's been
released barreling down

the valley is
the Abu Mansour Dam.

[Rob] That wall of water crashes
into the reservoir.

-[water running]
-[dramatic music playing]

And that reservoir level
rises very, very quickly.

Built to withstand a load

at least five times greater
than that of the Al-Bilad Dam,

the designers hoped
that the Abu Mansour Dam

would be able to absorb
the additional load

imposed on it
and protect the city below.

However, within 30 minutes,
the levels quickly surpass

the height of the wall,
and, as with the Al-Bilad Dam,

the water begins to overflow,
crashing against the base

on the other side,
but that's not all.

A history of poor maintenance
leads to another devastating

factor that transforms
this final barrier to the city

into a massively
destructive force.

[dramatic music playing]

The Abu Mansour Dam had already
been crumbling

for several years, with cracks
forming on its surface.

When this raging wave
strikes the wall

during that dreadful night,
it seeps into these cracks,

creating what engineers
call -- piping.

If you allow water to pass
through even the smallest gaps

within your wall, those gaps
can start to open up and grow

over time until your wall
is weakened.

[dramatic music playing]

[Rob] That water makes
the dam wall unstable until,

at a point, the wall is
no longer strong enough

to hold back
that weight of water.

3:00 AM.

Weakened and under pressure
from all sides,

the Abu Mansour Dam
completely gives way.

[Dr. Shini]
A 30-foot-high wall of water

slams into the city below,

obliterating entire
neighborhoods in just seconds.

[dramatic music playing]

The lucky ones are those
who perish fast asleep,

no idea what's happened.

The unlucky ones are
those who actually experience

the terrifying view,
the terrifying sound

of this mass of water
crashing towards you,

knowing that there is
nowhere to escape.

Due to these fatal engineering
errors, an estimated

24,000 people have died,
and thousands more

are left homeless,
having lost everything.

A humanitarian disaster
that serves as a reminder

of the importance
of maintaining dams

if we want them to continue
to protect us

rather than destroy us.

[somber music continues]

Examples of fatal engineering
can be the result

of mistakes in construction.

They can be the result
of mistakes in design

and calculations of materials
and dimensions, or they can be

the result of mismanagement
and lack of maintenance.

So what happens
when all three are at play?

[enigmatic music playing]

With its 21 million
inhabitants, or ten percent

of the Brazilian population,
the state of Minas Gerais

is one of the richest and most
dynamic in the country.

Known for mining activities,
a wealth of minerals such as

gold and diamonds,
it alone accounts

for almost 10% of Brazil's GDP.

The Córrego do Feijão iron mine

in the municipality
of Brumadinho

is one of the beating hearts
of the local economy.

[Rob]
It is the biggest employer.

Families who live together
in the town

work together in the mine.

[Daniel] This mine has been
in existence for decades.

And one of the things that
happens in iron ore mining is

there's a lot
of waste generated.

This is called tailings.

[Rob]
And at the Brumadinho mine,

similarly to many iron
ore mines, it was stored nearby

and contained with what's called
a tailings dam.

At 86 meters high, the height
of a 30-story building,

Brumadinho Dam B1 contains
12 million cubic meters

of iron ore tailings,
enough to fill 480

Olympic-sized swimming pools
with a highly toxic liquid.

But on this day,
January 25, 2019,

it's about to trigger
the most devastating event

the region has ever seen.

12:27 PM, Brumadinho dam.

[Daniel] The workers are taking
a break, eating lunch.

The dam is in the distance,
and then there is a deep rumble.

It's 12:28 PM, when the mine
surveillance cameras capture

these frightening images

straight out
of a Hollywood movie.

[earth rumbling]

[Daniel] If you're underneath
the dam,

it looks like the entire surface
of the earth has detached

and is now rushing towards you.

[Daniel] It is impossible
to survive an encounter

with this type of material,

a toxic mixture
of mud and water.

And while --
not be moving very fast,

it will consume
whatever in its path.

Buildings, bridges, roads,
and railroads are engulfed

by the merciless
70-kilometer-per-hour wave

of mud that devours
everything in its path.

[dramatic music playing]

[rumbling]

In all, the disaster led
to the death of 270 people.

[mournful music playing]

A humanitarian
and ecological disaster.

[Dr. Shini]
Riverbanks turn orange,

fish stocks are wiped out
due to a lack of oxygen,

and irrigation water,
needed for agriculture,

is rendered deadly.

[helicopter engine whirring]

This tsunami of toxic mud
contaminated 700 kilometers

of river and affected the lives
of 250,000 people.

It is the most devastating
mining disaster

in Brazil's history.

[Dr. Shini] What was
the trigger point that caused

such a catastrophic collapse?

And could it have
been prevented?

First, we need to understand

how this unique
structure works.

Tailings dams are built
like a layer cake.

An initial dike upstream
of the mine,

constructed in 1976, serves as
the base for what will become

this enormous
86-meter-high structure.

[Rob] You're building a wall,

basically out
of your waste material

that's enough to contain
the waste behind it.

And you can build on top of it.

[Rob] It's a fairly convenient
and cheap means of storing

waste material
and keeping it

in a place that's contained.

Or at least, that's the idea.

The tailings are mostly liquid,
soft, and toxic.

To solidify the material,
it had to be drained.

[Rob] All the waste material
that's built up behind

this rather rudimentary
embankment wall

is allowed to separate
over time so that the solids

fall away from any liquid
or water that's left on the top.

That water, then over time,
evaporates, and you've got

a solid base,
which you can then start

to put more waste
on top of and go again.

The drying is important.

And so wet tailings, bad.
Dry tailings, good.

Over time, the site forms
a large, solid structure

that becomes
part of the landscape

and is reclaimed
by nature.

But this method of storage
also has its drawbacks.

It's not as structurally sound
as building a barrier, a wall,

to contain something behind it
out of concrete and steel.

And the waste in the dam
can sometimes mix with water,

making it tricky to keep
everything dry and safe.

And too much water
can weaken the dam.

Water, the enemy
of every tailings dam.

[Daniel] One of the most
important things

for a tailings dam is to control
where the water goes, right?

If the water impregnates
the tailings dam,

the mechanical stability
of the dam can be compromised.

Although the Brumadinho Dam
reached its maximum

operating level in 2016,
water was to become the trigger

for the disaster to come.

[rumbling]

Three years later,
the dam collapse would

devastate homes,
livelihoods, and lives.

The mine owners
were aware the problems

the water was creating
and tried to find solutions.

The first engineering technique
to help remove excess water

from the accumulated tailings
involved creating a large,

flat, and dry area
behind the dam,

which they called
the beach.

[Dr. Shini] As fresh tailings
are poured across the beach,

they're spread out like
a thin layer of mud,

speeding up the drying process,
similar to a puddle of water

drying in the sun.

It also had the effect

to draw out some of the moisture
from the waste tailings dam

and dry that out and, in turn,
give more stability

to that tailing structure.

Following this,
the engineers devised

an additional process
to remove water from the dam.

[Dr. Shini] Channels or canals
are built into each new layer

as it's created.

Pumps would then move the water
away from the site.

Although these methods are
normally quite effective

in ensuring the safety
of the Brumadinho Dam,

they would not be enough.

[thunder crashing]

[menacing music playing]

By the end of 2018,
southeastern Brazil experienced

unusually heavy
and prolonged rainfall.

As a result,
the pumps struggled

to function, and the drains
could not keep up

with the deluge,
often becoming clogged.

[Rob] Rather than evaporating,
all of that water

was being absorbed
by the waste materials,

making it much less
structurally sound

and much less capable of holding
anything back behind it.

With water and moisture levels
in the dam rising faster than

they could be reduced,
the engineers came up

with what they believed
to be a perfect solution.

They came up with a third
solution, and that was to drill

a series of 50-millimeter
boreholes through the dam walls

[Dr. Shini] The horizontal drain
holes would effectively act

like straws
and allow trapped water

behind the trailing walls
to escape.

The drains did not allow enough
water to escape as needed.

Worse, they weakened
the structure.

[Rob] And whilst
these horizontal drain holes

did allow some water to drain,
they would be the crucial part

of mistakes that were made
at a mining dam.

On June 11, 2018, a borehole
in the wall of the first dike

at the base
of the dam collapsed.

Mud and waste spilled
from the dam.

The drainage program was
immediately abandoned.

The problem now is the dam has
become mechanically compromised

and is on the verge
of instability.

[Rob] Employees are working

to backfill the holes
with concrete now.

Anything they can
think of to bring

structure back into the dam.

Although the Brumadinho Dam
appeared solid

from the outside,
inside it was compromised

and filled with water.

What seemed like the ideal
solution to save the dam

from water infiltration

ultimately weakened
the structure

and led it to its collapse

on January 25, 2019.

[Daniel] On the day
of the collapse,

even though the mine
has been indicating

that it's in a little bit
of trouble.

Nothing really indicates
that a catastrophe

is about to happen.

[birds chirping]

12:28 PM.

While most workers were having
lunch at the site's canteen,

the dam collapses.

-[dramatic music playing]
-[rumbling]

[Daniel] The entire structure
of the dam

gives way
in one large,

sort of, sweeping motion
where the front face of the dam

cracks loose and then begins
to slide forward.

[Dr. Shini] Within seconds,
a 30-meter-high wall

of toxic material races
towards the canteen

and surrounding buildings,

wiping out everything
in its path.

[debris rumbling]

[epic music playing]

In total, the Brumadinho Dam
collapse results in 270 deaths,

with three people
still missing.

Their bodies remain buried

under more than
seven meters of mud.

[mournful music playing]

[speaking Portuguese]

[speaking Portuguese]

T housands of people
who depend on the river

saw their livelihoods
instantly destroyed.

[speaking Portuguese]

A tragedy
with multiple consequences,

and not the first
to hit the region.

Well, not only Brumadinho,
but other tailings dam collapses

happening in Brazil.

A similar disaster occurred
just four years earlier,

100 kilometers east,
in the town of Mariana.

In addition
to its mining industry,

the state of Minas Gerais
has the largest number of dams

in Brazil, with a total
of 3,000 structures

of all types.

Following the Mariana
catastrophe, Vale,

the mine's owner, was ordered
to pay 7 billion US dollars

for cleanup efforts
and compensation

for the victims' families.

Tailings dams can be
a practical solution,

but only when they're
meticulously managed

and maintained to avoid
the kind of environmental

disaster that happened
at Brumadinho.

[Daniel] The fatal engineering
that exists in this

is the lack of ability
of the engineers to maintain

the health of the dam.

This was a structure
that is always teetering

on the edge of failure.

For millennia, dams have played
a vital role in human life,

allowing us to control one
of the most precious resources

on our planet, water.

But history has
repeatedly reminded us

that these colossal structures
can also destroy life.

[Daniel Nature will always erode
and degrade the structure.

Even the pyramids, even though
they're thousands of years old,

they show the signs
of weathering.

Dams are the same way.

You have to put the time,
effort, and energy

into maintaining a structure,

otherwise it will
always collapse.

These massive dams must remain
marvels of human engineering

and not examples
of fatal engineering.