I want you to picture a spring evening. OK. It's
April 1915, and we are on the Western Front.
Right in the thick of it. Exactly. The sun is
just starting to set over this heavily scarred
landscape in Western Belgium. And for a brief
moment, there might actually be a lull in the
fighting. A rare quiet moment. Yeah. But then,
if you're looking out across the craters, you
see something strange. Something that shouldn't
be there. Right. a low heavy cloud begins to
drift across the mud. It's not fog. It is this
sickly yellow green color. Wow. And as it creeps
silently toward the allied trenches, it is about
to completely shatter the rules of engagement.
I mean, it's going to forever change the face
of modern warfare. It really is a genuinely chilling.
pivot point in military history. I mean, that
cloud represented the definitive end of one era
of combat. And the terrifying dawn of a new one.
Exactly. A highly mechanized chemical reality.
And that is exactly what we are getting into
today. Welcome to this deep dive. Glad to be
here. Today, we're relying on a single comprehensive
source. It's a meticulously detailed Wikipedia
article on the Second Battle of Ypres. A really
fascinating read. It is. Our mission for this
deep dive is to unpack not just the military
maneuvers of this historic month -long clash,
but the horrifying introduction of weapons of
mass destruction to the battlefield. The human
cost was just, it was unprecedented. Yeah. We're
going to look at the desperate human ingenuity
that followed that yellow -green cloud, and really
what this whole ordeal means for how we understand
massive technological leaps. Especially when
they happen in times of absolute crisis. Right.
To really grasp the impact of this, we need to
properly set the stage. The Second Battle of
Ypres took place from April 22nd to May 25th,
1915. Over a month of fighting. Yeah. Geographically,
we are looking at the Ypres salient in western
Belgium. At this particular time, the northern
end and the eastern bulge of this salient were
being defended by a mix of French, Canadian,
and British divisions. And as we are about to
explore, this battle marked the first mass use
of poison gas by Germany on the western front.
Okay, let's unpack this. Because the origin of
this attack actually starts far away from the
mud of the trenches. Right. It starts in the
pristine laboratories of the German Empire. Exactly.
This period is often referred to as the chemists'
war. And there's a dark historical absurdity
to it. You essentially had some of the most brilliant
minds of the 20th century arguing over the optimal
deployment of chemical agents. Like they were
trying to design a more efficient household cleaner
or something? It's so strange. Initially, you
had this German chemist, Walther Nernst. He was
actually serving as a volunteer driver at the
time. OK. He pitched the idea of using tear gas
to a German general staff officer to clear out
opposing trenches. Right. But then another chemist
steps in, Fritz Haber. Yes. He observes a field
test of Nernst's tear gas and essentially says,
It isn't enough. He pushes for something far
more lethal. Heavier than air chlorine gas. Which
completely shifts the scale of what they're trying
to do. What's fascinating here is the sheer logistical
nightmare required to turn Haber's scientific
theory into a battlefield reality. Because they
couldn't just drop it from a plane. Right. We
aren't just talking about dropping a bomb. The
German troops had to manually haul 5 ,730 individual
gas cylinders. into the front lines. That is
why. And to give you some perspective, the largest
of these cylinders weight 88 pounds. Almost 90
pounds of dead weight. Yes. They had to carry
them through the trenches at night, bury them
in the parapets, and cover them with sandbags.
Just to protect them from incoming artillery.
Exactly. It was a massive physical undertaking.
And it was supervised on the ground by Haber
himself. Along with other prominent scientists.
Right, guys like Otto Hahn, James Frank, and
Gustav Hertz. Imagine being an infantryman tasked
with dragging an 88 -pound metal cylinder of
poison through trench mud. Knowing a single stray
bullet could rupture it right next to you. It's
terrible. and it gets even more complicated because
they couldn't just open the valves and spray
it. The liquid chlorine inside would cause the
valves to freeze solid upon release due to the
rapid temperature drop. Ah, basic chemistry working
against them. Right. So they had to siphon the
liquid chlorine, allow it to vaporize, and then
they literally just had to wait for the breeze.
Wait for the wind. Yeah, wait for the wind to
blow in the exact right direction to carry the
vapor toward the British and French lines. If
we connect this to the bigger picture, we have
to look at the strategic motivation of the man
who approved this deployment. General Erich von
Falkenhayn. Yes, the professional head of the
German Army. This wasn't simply a terror tactic
designed in a vacuum. He had a specific goal.
Falkenhayn had a very specific strategic objective.
He wanted to use the profound shock and chaos
of a massive gas attack to mask the transfer
of his military units to the Eastern Front. Because
the Austro -Hungarian Army were struggling. Exactly.
They were taking heavy losses against the Imperial
Russian Army at the time. So Falkenhayn needed
a massive distraction on the Western Front. So
he could quietly move his troops east to reinforce
them. And that brings us to the reality of April
22, 1915, the Battle of Gravenstaffel Ridge.
The first day. It's about five in the evening.
The troops are likely settling in, maybe preparing
evening rations. The wind is finally cooperating
for the Germans. Yes, the wind is blowing in
the right direction. The order is given and the
German 4th Army releases 168 tons of chlorine
gas. Across a four -mile front. Between the hamlets
of Langmark and Grabenstafel and sitting right
in the path of this rolling cloud are the French
87th Territorial Division and the 45th Infantry
Division. These were men entirely unprepared
for chemical warfare. No warning at all. None.
The 87th was made up of older reservists, and
the 45th comprised troops from French North Africa.
When that heavy gas rolled into their trenches,
displacing the oxygen. The human toll was instantaneous.
In that initial wave, the French suffered between
2 ,000 and 3 ,000 casualties. With up to 1 ,400
fatalities. Reading Colonel Henri Mordach's account
of the 45th Division really puts you in the boots
of those soldiers as the gas enveloped them.
What did he say? He described his men as haggard.
Their overcoats thrown off or opened wide, scarves
pulled off. Just desperate for air. Running like
madmen, directionless, shouting for water, spitting
blood. He noted some were even rolling on the
ground, making desperate efforts to breathe.
It is a portrait of absolute panic. Total chaos.
And structurally, this attack did exactly what
it was designed to do. It created a massive 3
.7 mile undefended gap. in the allied line the
front was completely broken but wait hold on
i want to pause here okay they just punched a
nearly four mile wide hole straight through the
allied lines the road teapot is practically wide
open wide open Why didn't they just keep walking?
Why wouldn't Falkenhayn have had reserves ready
to exploit that gap immediately and take the
city? It is the ultimate tactical irony of this
battle. Yeah. The Germans had just engineered
a massive breakthrough, but they were terrified
of their own weapon. Really? The German infantry
advancing behind the gas cloud were only equipped
with rudimentary protection, just basic cotton
pads soaked in a sodium thiosulfate solution.
That's not much. No. They didn't trust the masks.
They didn't trust the gas to dissipate quickly
enough. So they held back. Instead of pushing
their immense advantage and marching straight
into Ypres, almost unopposed, they advanced very
cautiously. They hesitated. They hesitated and
ultimately decided to dig in at the small villages
they had just captured. And that hesitation,
that fear of their own creation gave the Allies
a tiny precious window of time. A very brief
window. The Canadian troops who were defending
the southern flank of this newly created gap
had to step up. Interestingly, the Canadians
actually recognized what the gas was right away.
Because of the smell. Yeah, the chlorine smelled
exactly like the chemicals they used to purify
their drinking water. That familiarity, as grim
as it was, likely helped them process what was
happening faster than the French units had. But
the situation was still utterly desperate. Beyond
desperate. That night, after 11 p .m. The 10th
and 16th Canadian Battalions were ordered to
launch a counterattack into the gap at a place
called Kitchener's Wood. Put yourself in their
boots for a second. It's pitch black. You have
absolutely no idea what the terrain looks like.
Because there hasn't been any reconnaissance.
You just know the enemy is out there in the dark
and the air still smells like poison. Halfway
to their objective, they hit unexpected obstacles.
A hedge interwoven with wire. And they take heavy
small arms fire. So they launch an impromptu
midnight bayonet charge. They physically ran
into the dark and fought hand -to -hand. Incredibly,
they succeeded in clearing the woods of German
soldiers. But the cost was unfathomable. How
bad was it? Those battalions suffered a staggering
75 % casualty rate in that single action. 75
%? That's devastating. It's a testament to raw
courage, certainly. But it also heavily underscores
the brutal reality of throwing human bodies against
a mechanized chemical advantage. And unfortunately
for the troops on the ground, the terror was
only just beginning. Right. Because two days
later, on April 24th, we moved to the Battle
of St. Julian. This is the moment the terrifying
realization truly sets in for the Allies. The
gas attack wasn't a one off experiment. It was
their new standard tactic. At St. Julian, another
massive yellow -green cloud was released. The
troops there described the gas as having a highly
distinct odor. Something resembling a mix of
pineapple and pepper. The initial confusion was
profound. French officers actually thought the
advancing cloud was just a conventional smoke
screen. Meant to hide an infantry advance. Exactly.
It wasn't until the soldiers started collapsing,
complaining of severe chest pains and a burning
sensation in their throats, that the true nature
of the attack was understood. Here's where it
gets really interesting, because with no official
gas masks issued, the troops had to improvise
instantly. They had to think fast. And they relied
on some incredibly quick thinking from their
medical personnel. Canadian medical officers.
Specifically, chemists and bacteriologists, Lieutenant
Colonel George Naismith and Captain Francis Scrimgeour,
they identified the chemical properties of the
chlorine. And what did they do? They passed an
urgent order down the line for the troops to
urinate on their handkerchiefs or cotton pads.
And hold them tightly over their mouths and noses.
It sounds shocking to modern sensibilities. But
chemically, it was entirely sound advice in a
life or death scenario. How does that work? The
urea, naturally present in human urine, actually
reacts with and neutralizes the chlorine gas.
It creates a compound called dechlorurea. Wow.
In the absence of an actual engineered respirator,
that damp urea -soaked piece of cloth was literally
the only chemical barrier standing between a
soldier's respiratory system and a highly caustic
gas. But even with that improvised defense, the
reality on the ground was a nightmare. We get
a sense of this visceral horror from the account
of Private W. Hay of the Royal Scots. He was
just a 20 -year -old kid who arrived in Eeper
right after the first gas attack. He described
walking along the railway line and seeing the
road choked with refugees. Moving alongside dead
and dying civilians and soldiers. He called it
a horrible sight that he would never, ever forget.
To truly understand what these men were facing,
we have to look at the physical effects of chlorine
exposure. It is agonizing. Lance Sergeant Elmer
Cotton provided a very clinical, grim description.
What did he say? He stated that the effects of
chlorine gas were equivalent death to drowning
only on dry land. That is a brutally mechanical
way to describe it. It completely strips away
any romanticized idea of combat. Drowning on
dry land. He detailed the splitting headaches,
the terrific first. He noted that drinking water
was supposedly instant death. Oh, man. And the
coughing up of a greenish froth from the stomach
and the lungs. That's awful. You know, the skin
turning greenish black and yellow due to oxygen
deprivation and the glassy stare of the eyes.
Just completely helpless. As you bluntly put
it, it is a fiendish death to die. Yet amidst
all that unimaginable panic and pain, you still
had acts of almost unbelievable discipline and
courage. Lance Corporal Frederick Fisher is a
prime example. During the fighting at St. Julian,
he went out not once but twice with just a handful
of men and a Colt machine gun. He set up his
position under heavy fire and successfully prevented
the advancing German troops from passing through
the village. And flanking the Canadian front
line. He saved countless lives and held the line
together. But he was killed in action the very
next day. His actions were vital. The delay caused
by localized stands like Fisher's combined with
the German infantry's ongoing fear of moving
too quickly into the residual gas. It gave the
British and Canadian troops just enough time
to plug that massive gap before the entire line
collapsed. But plugging the gap didn't mean the
battle was over. No, it just meant the shock
value of the initial gas attack faded and the
relentless industrial grind of conventional warfare
took over. Which leads us into the subsequent
massive engagements at Friesenberg and Bellward.
stretching this nightmare deep into May. Exactly.
The narrative of Ypres often focuses so heavily
on the gas that we forget the sheer scale of
the conventional slaughter that followed. Between
May 8th and 13th at the Battle of Friesenberg,
the Germans brought their field artillery forward.
They assembled three entire corps and subjected
the British 27th and 28th divisions to a massive
punishing bombardment. We are talking about days
of relentless heavy shelling on static positions.
The tactical nightmare of holding a trench under
that weight of fire is hard to wrap your head
around. You can't retreat, but you also can't
advance. You just have to sit there and take
it. The decimation of individual units during
this phase is staggering. Look at Princess Patricia's
Canadian light infantry. They were ordered to
counterattack and hold the line at Friesenberg.
They went in with 700 men. By the time the artillery
barrage and the fighting were done, they were
reduced to a mere 150 survivors. Essentially,
an entire regiment was wiped out in a matter
of days. They were in no shape to fight. And
even as this conventional artillery slaughter
was peaking, the chemical threat remained a constant
terror. During the Battle of Belward on May 24th,
the Germans launched yet another major gas attack.
But by this point, the tactics were rapidly evolving
on both sides. There's this eerie, almost cinematic
detail from Belward. The Germans started throwing
red lights flares up over their own trenches.
This was a visual signal to their own men that
a gas release was imminent. And because the Allies
were watching the sky, It gave commanders like
Captain Thomas Leahy of the Royal Dublin Fusiliers
just enough warning. He noted that seeing those
red lights gave them exactly enough time to get
their makeshift respirators on before the gas
washed over them. It became a macabre routine.
You see the red flare, you grab the chemically
soaked cloth, you brace for the cloud to pass
over you. and then you immediately prepare to
fight off the infantry assault that would inevitably
follow right behind it. So what does this all
mean? When the guns finally fell silent on May
25th, the ledger of war was almost too massive
to comprehend. The casualty numbers are absolutely
devastating. The records show over 35 ,000 German
casualties. The British suffered 59 ,275 casualties.
And the French suffered an estimated 21 ,973
casualties. Strategically, After all that blood
and poison, the British forces were ultimately
forced to withdraw to a new defensive line three
miles closer to Ypres. The salient was compressed
and the city of Ypres itself was completely demolished
by the relentless artillery fire. It was a shattered
landscape. But the Allies did survive the onslaught.
They held the line. And that survival forced
an incredibly steep learning curve. The Canadian
Division alone suffered nearly 6 ,000 casualties
in just the first couple of weeks. They paid
in blood to learn that 19th century tactics had
absolutely no place in a 20th century war. Up
until in Prey, military doctrines still heavily
favored large linear formations. But commanders
quickly realized that moving a full company of
men as a single bloc was completely suicidal
against guns and poison gas. One gas cloud or
one well -placed machine gun nest could wipe
out a hundred men in seconds. This battle triggered
a massive shift in how armies organized themselves.
Because of the lessons learned here, by 1917
The primary tactical maneuvering unit would be
reduced from a large company down to a much smaller,
far more agile section level unit. Allowing for
squad level autonomy and dispersed movement.
They also learned hard lessons about the reality
of their equipment. It wasn't just about tactics.
It was about the lethal disconnect between procurement
politics and trench reality. Take the Canadian
Ross rifle. It was a finely made weapon, highly
accurate on a pristine target practice range.
But in the mud, grit and rapid fire. conditions
of the Belgian trenches, it jammed constantly.
A rifle that jams the second it touches mud is
worse than useless. It actively costs lives.
It forced soldiers to throw them away and scavenge
Lee -Enfield rifles from fallen British troops.
We also see a rapid, almost frantic technological
race to counter the chemical threat. The evolution
of protection moved at an incredible pace. They
went from those desperate, urine -soaked cotton
pads in April. to mass producing the P helmet,
also known as the tube helmet, by the end of
1915. These were flannel bags soaked in sodium
phenate and sodium phiosulfate. And just to clarify
the chemistry there, sodium phiosulfate basically
acts as a chemical sponge. When the chlorine
gas hits the soaked fabric, the phiosulfate reacts
with it. Converting the highly toxic chlorine
into benign, water -soluble compounds like sodium
chloride. Just basic salt. Right before it can
reach the lungs. It was a chemical shield. And
the arms race didn't stop there. By early 1916,
as the Germans introduced new chemical agents,
the Allies developed the pH helmet. Adding hexamethylenetramine
to make it effective against phosgene. An even
stealthier and deadlier gas that both sides eventually
deployed. Out of all this horror, all this industrial
scale death and frantic adaptation, there is
also a profound cultural legacy that I think
many of you listening will immediately recognize.
It was during this exact battle, surrounded by
the devastation we've just spent the last 20
minutes describing, that a Canadian medical officer
named Lieutenant Colonel John McCrae sat down
and wrote a poem. That poem is In Flanders Fields.
It's an incredible juxtaposition. Such a poignant,
enduring piece of literature was born born directly
out of the chaos of the first mass chemical attack
in history. It gave a voice to the dead that
is still recited on Remembrance Day and Memorial
Day over a century later. It really makes you
pause. I want you, the listener, to try and imagine
what it would be like to stand in those trenches
in April 1915. You are facing an entirely unprecedented
form of technological terror. A creeping cloud
that turns the very air you breathe into a weapon.
And yet amidst all that panic, People found the
resolve to hold the line with literally nothing
but a chemically soaked piece of cloth over their
mouths. This raises an important question, especially
for us today. When we look at rapid disruptive
technological change, whether it's in modern
warfare, artificial intelligence, or bioengineering,
we often feel entirely overwhelmed by the pace
of it. But EPRI shows us the extreme edge of
human adaptability. It demonstrates how incredibly
quickly we can analyze a completely novel existential
threat, adapt our defenses, and endure. Endure,
but at a terrible, terrible cost. Always a cost.
And that brings me to a final thought I want
to leave you with today. Something to mull over
on your own after this deep dive is done. We
spent a lot of time talking about the brilliant
German chemist, Fritz Haber. The man who forcefully
advocated for and directly supervised this deadly
chlorine gas attack. Well, consider this. Fritz
Eber is the exact same scientist whose work on
synthesizing ammonia for fertilizer currently
sustains the global food supply. Without his
chemical discoveries regarding nitrogen fixation,
billions of people alive today simply could not
be fed. So how do we reconcile the legacy of
brilliant minds that possess the dual capacity
to both feed the world and engineer its most
horrific Something to think about. Thanks for
joining us on this deep dive.