September 2, 2026 • 12 mins
Japanese nuclear worker Hisashi Ouchi is often called on the internet “the world’s most radioactive man.” That’s not exactly true, but it gets the point across about how severe the fatal dose of radiation he received was.
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Speaker 1 (00:04):
Hey, and welcome to the Short Stuff. I'm Josh, and
there's Chuck, and Jerry's sitting in for Dave, and this
is Short Stuff, a really sad edition.
Speaker 2 (00:13):
Yeah, for sure, because this is about a nuclear accident,
and one very famous victim of that accident, a man
in Japan named Hisashi Ouchi.
Speaker 1 (00:24):
Mm-hmm.
Speaker 2 (00:25):
Who at the time was a 35-year-old worker at a
nuclear facility. And he got a massive blast of radiation
in 1999. It was called a criticality accident. And what
was the name of the town?
Speaker 1 (00:43):
In Takaimura. Takaimura. Okay, great.
Speaker 2 (00:47):
Yeah.
Speaker 1 (00:47):
Or no, Tokaimura, sorry. And that's called the Tokaimura nuclear
accident is what it's called. And like you said, it
was a criticality because there wasn't like a nuclear explosion
or anything like that. It was an uncontrolled nuclear fission
reaction that these guys accidentally created while they were doing
their job processing uranium oxide into usable uranium-235 fuel to
(01:14):
be used in an actual nuclear reactor. This is not
a nuclear plant. It was the kind of plant that
produces fuel for nuclear plants.
Speaker 2 (01:23):
That's right. This is the morning of September 30th, 1999.
And what they specifically were doing in that moment was
they were dissolving that uranium oxide, like you were saying.
And this was the procedure. What I'm describing now is
the approved procedure, actually. Yeah, right. So they were supposed
(01:43):
to have dissolved that uranium oxide in a geometrically safe vessel.
And then what you end up with is uranyl nitrite solution.
And you put that into a buffer tank and then transfer,
you know, little bits of that into a precipitation tank.
This company, is it JCO is the name of the company?
Speaker 1 (02:05):
Yeah.
Speaker 2 (02:06):
They said, all right, we're going to speed this up.
And this procedure is not approved. But what we want
you guys to do is mix the solution in stainless
steel buckets and then pour it directly into the precipitation tank.
Speaker 1 (02:20):
And not only pour it directly in the precipitation tank,
pour so much in there that we have like five
to six times the approved amount in that precipitation tank
at once, right?
Speaker 2 (02:32):
I think there's like seven times. Okay.
Speaker 1 (02:34):
A lot, a lot more than was supposed to be
in there. And I just want to point out, like
you were saying, there was an approved procedure and JCO said,
nuts to that. We're going to do this faster one. Right.
That's just what they were doing with their workers. It's
crazy because this is nuclear uranium 235 fuel that they're making.
And so when they put in these three workers, including
(02:56):
Hisashi Ouchi, when they put in the seventh bucket of
this stuff into the directly in the precipitation tank, There
were 16.6 kilos or 36.6 pounds of uranium in there,
which is way more than was allowed to be in there.
I think it was 2.4 keys or kilograms that was
(03:16):
allowed to be in there. And they had 16.6, Chuck.
Speaker 2 (03:19):
Yeah. So that reached critical mass pretty quickly and started
a self-sustaining nuclear chain reaction. And like you said, it
wasn't like an explosion or anything like that, but it
was a huge burst. of neutron and gamma radiation, like
incredible Hulk levels. And it went on and off for
about 20 hours until the emergency workers finally drained water
(03:43):
from the tank's cooling jacket and then added boric acid
to absorb the neutrons. But, you know, very sadly, OUCHI
received a dose equivalent of 17 sieverts. It's kind of
hard to like get an exact calculation, but It was
an incredibly large amount of radiation, like so much that
(04:04):
they have. He's been called the most radioactive man in history,
which is a bit of a misnomer because he had
this burst of radiation. But it's not like he was
walking around like radioactive to other people or anything like that.
Speaker 1 (04:17):
It's a little surprising to me, but OK, well, I'll
take that. I did a little bit of Josh math here, Chuck.
Speaker 2 (04:25):
Oh, boy.
Speaker 1 (04:26):
Well, it's not even Josh math. It's more Josh checking.
So you said that Oichi received 17 sieverts of radiation, right? Yeah.
I'm not laughing at that.
Speaker 2 (04:37):
I'm laughing at your math, by the way.
Speaker 1 (04:39):
No, I understand.
Speaker 2 (04:39):
Yeah.
Speaker 1 (04:40):
One millirem is equal to 0.00001 sieverts. Okay? Okay. You
get 20 millirems from a chest X-ray. He got 17
sieverts all at once. Wow. I mean, that's just such
a mind-boggling amount of radiation that I can't believe he
(05:02):
didn't die immediately. I say we take a break and
come back and talk about Ochi's agonizing 83 days of
life that followed that radiation exposure. All right.
Speaker 2 (05:12):
We'll be right back.
Speaker 1 (05:36):
So, Chuck, before we broke, I was saying I was
surprised that he didn't die immediately.
Speaker 2 (05:40):
Yeah.
Speaker 1 (05:40):
The reason he didn't die immediately is because it takes
a little while for the incredible damage that the radiation
did to his body to actually take effect. But what
it did, essentially, was it blasted through every cell in
Hisashi Oichi's body and damaged the DNA inside so much
(06:02):
so that the doctors caring for him said that he
had completely, or the radiation had completely shattered his chromosomes.
The actual packets that hold the DNA in your cells
were just shattered. They couldn't find chromosomal structures throughout his
body that weren't just totally messed up.
Speaker 2 (06:24):
Yeah, we should mention there were three guys in the
immediate area. He was the one closest to the tank.
There was another guy a little less close to the tank.
And then I guess the third guy even less close
to the tank. Ouchi was taken to a local hospital
at first, obviously, like very quickly, and then transferred to
the National Institute of Radiological Sciences in Chiba, but then
(06:46):
eventually would end up at the University of Tokyo Hospital
for some really extensive specialized treatment. Specialized meaning like they
had no roadmap for this. So they were kind of
trying anything.
Speaker 1 (06:59):
Exactly. they got in touch with his sister who was like, hey,
he is not really able to produce new white blood cells. Basically,
any fast-growing, fast-regenerating cell, it took the damage the most.
And that's where it showed up first because those are
the cells that are dividing. And now that their DNA
(07:20):
is messed up, they're dividing in all sorts of terrible ways.
So the things that made up like the lining to
his gut, those fast-dividing cells, they started to show problems first.
His skin... And then his bone marrow that produces white
blood cells, red blood cells, all sorts of really important stuff.
That was probably the biggest problem because he was very
(07:43):
vulnerable to infection without a bunch of white blood cells
or not producing correct ones anymore. So they went to
his sister and said, hey, can you donate some bone marrow?
And she did. Yeah.
Speaker 2 (07:54):
So, you know, like I said, they were trying blood
transfusions at first, stem cell transplants. And that's where his
sister came into play. And initially, it showed like that
transplant produced some new white blood cells. But very quickly,
they started getting damaged and, you know, basically in the
(08:15):
same way. He was just so riddled with it. And
his skin and his intestinal lining couldn't regenerate normally. He
had to constantly get fluids like replaced all throughout his body.
He was on respiratory support. and like organ failure started
to set in. Yeah.
Speaker 1 (08:34):
So the guy who was second closest when that radiation
blast went off, his name was Masato Shinohara. And he
died from his injuries in 2000, April 2000. But about
four months before, on December 21st, 1999, Hisachi Ouchi died
at the University of Tokyo Hospital. And it had been
(08:56):
83 days since he had undergone that blast of radiation.
And so, of course, this made really big news around
Japan and around the world. This is nuts that anybody
even lasted that long, let alone just the grisliness of
the whole thing. So everybody was like, how did this
happen at all? And they started looking at JCO. It
(09:17):
turns out JCO was a terrible, terrible company that had
no business doing something as important and dangerous as nuclear
fuel production.
Speaker 2 (09:29):
Yeah, for sure. That third worker survived, by the way,
out of the three. But yeah, JCO had allowed a
lot of shortcuts to happen. Like you said, the instructions
just for this were that wasn't the approved procedure. There
was not a lot of regulatory approval going on. The
workers didn't have safety training that they needed. The facility
(09:51):
didn't have a critical incident alarm, which is crazy. They
just I guess they thought that like there wouldn't be
that kind of accident there.
Speaker 1 (09:59):
That's what happened at Three Mile Island. Hubris.
Speaker 2 (10:01):
Yeah, that's right. That same thing. They also weren't conducting
the kind of inspections routinely that they needed to. And
that might have turned up like, hey, this process that
we're using is like really unsafe and we should be
using the approved process.
Speaker 1 (10:13):
So I just want to point out, I think it's
probably clear, but I just want to make 100 percent clear.
These three workers were not taking their own shortcut. They
were doing the procedure that their company was telling them to,
which was a dangerous shortcut. So the dangerous shortcut was
official company procedure. Right. Yeah.
Speaker 2 (10:32):
So as far as the official like procedure. blame or whatever,
the International Atomic Energy Agency said it was human error
combined with serious breaches of safety principles. For JCO's part, they,
in 2003, six of the officials got suspended prison sentences
for professional negligence. The company was fined and they couldn't,
(10:54):
they had shut down the plant, didn't they?
Speaker 1 (10:57):
They did. They would think it was the first time
ever that a company lost its license to, to, enriched
nuclear fuel in Japan. Yeah. And then also they were like,
you know, these safety inspectors that didn't do the proper
inspections that were to turn up that issue with the
different procedure, they fell down too. So Japan really kind
(11:18):
of bulked up its nuclear stuff and now everything's great. Yeah.
Speaker 2 (11:23):
I mean, you know, it exposed like what could happen.
And I think with every time we do something like this,
like It's like they're very sad stories, but it seems
like they come out on the other side with like,
all right, now we're trying to do it right. Don't
you think?
Speaker 1 (11:37):
Yeah, I think because in this case, JCO maybe wasn't
powerful enough to try to fight having to change. So
it did end up for the best.
Speaker 2 (11:46):
Yeah.
Speaker 1 (11:47):
Yeah. Anything else?
Speaker 2 (11:48):
I got nothing else.
Speaker 1 (11:49):
Well, I say you give it to him.
Speaker 2 (11:52):
Short Stuff is out. Stuff You Should Know is a
production of iHeartRadio. For more podcasts from iHeartRadio, visit the
iHeartRadio app, Apple Podcasts, or wherever you listen to your
favorite shows.
Hey, and welcome to the Short Stuff. I'm Josh, and
there's Chuck, and Jerry's sitting in for Dave, and this
is Short Stuff, a really sad edition.
Speaker 2 (00:13):
Yeah, for sure, because this is about a nuclear accident,
and one very famous victim of that accident, a man
in Japan named Hisashi Ouchi.
Speaker 1 (00:24):
Mm-hmm.
Speaker 2 (00:25):
Who at the time was a 35-year-old worker at a
nuclear facility. And he got a massive blast of radiation
in 1999. It was called a criticality accident. And what
was the name of the town?
Speaker 1 (00:43):
In Takaimura. Takaimura. Okay, great.
Speaker 2 (00:47):
Yeah.
Speaker 1 (00:47):
Or no, Tokaimura, sorry. And that's called the Tokaimura nuclear
accident is what it's called. And like you said, it
was a criticality because there wasn't like a nuclear explosion
or anything like that. It was an uncontrolled nuclear fission
reaction that these guys accidentally created while they were doing
their job processing uranium oxide into usable uranium-235 fuel to
(01:14):
be used in an actual nuclear reactor. This is not
a nuclear plant. It was the kind of plant that
produces fuel for nuclear plants.
Speaker 2 (01:23):
That's right. This is the morning of September 30th, 1999.
And what they specifically were doing in that moment was
they were dissolving that uranium oxide, like you were saying.
And this was the procedure. What I'm describing now is
the approved procedure, actually. Yeah, right. So they were supposed
(01:43):
to have dissolved that uranium oxide in a geometrically safe vessel.
And then what you end up with is uranyl nitrite solution.
And you put that into a buffer tank and then transfer,
you know, little bits of that into a precipitation tank.
This company, is it JCO is the name of the company?
Speaker 1 (02:05):
Yeah.
Speaker 2 (02:06):
They said, all right, we're going to speed this up.
And this procedure is not approved. But what we want
you guys to do is mix the solution in stainless
steel buckets and then pour it directly into the precipitation tank.
Speaker 1 (02:20):
And not only pour it directly in the precipitation tank,
pour so much in there that we have like five
to six times the approved amount in that precipitation tank
at once, right?
Speaker 2 (02:32):
I think there's like seven times. Okay.
Speaker 1 (02:34):
A lot, a lot more than was supposed to be
in there. And I just want to point out, like
you were saying, there was an approved procedure and JCO said,
nuts to that. We're going to do this faster one. Right.
That's just what they were doing with their workers. It's
crazy because this is nuclear uranium 235 fuel that they're making.
And so when they put in these three workers, including
(02:56):
Hisashi Ouchi, when they put in the seventh bucket of
this stuff into the directly in the precipitation tank, There
were 16.6 kilos or 36.6 pounds of uranium in there,
which is way more than was allowed to be in there.
I think it was 2.4 keys or kilograms that was
(03:16):
allowed to be in there. And they had 16.6, Chuck.
Speaker 2 (03:19):
Yeah. So that reached critical mass pretty quickly and started
a self-sustaining nuclear chain reaction. And like you said, it
wasn't like an explosion or anything like that, but it
was a huge burst. of neutron and gamma radiation, like
incredible Hulk levels. And it went on and off for
about 20 hours until the emergency workers finally drained water
(03:43):
from the tank's cooling jacket and then added boric acid
to absorb the neutrons. But, you know, very sadly, OUCHI
received a dose equivalent of 17 sieverts. It's kind of
hard to like get an exact calculation, but It was
an incredibly large amount of radiation, like so much that
(04:04):
they have. He's been called the most radioactive man in history,
which is a bit of a misnomer because he had
this burst of radiation. But it's not like he was
walking around like radioactive to other people or anything like that.
Speaker 1 (04:17):
It's a little surprising to me, but OK, well, I'll
take that. I did a little bit of Josh math here, Chuck.
Speaker 2 (04:25):
Oh, boy.
Speaker 1 (04:26):
Well, it's not even Josh math. It's more Josh checking.
So you said that Oichi received 17 sieverts of radiation, right? Yeah.
I'm not laughing at that.
Speaker 2 (04:37):
I'm laughing at your math, by the way.
Speaker 1 (04:39):
No, I understand.
Speaker 2 (04:39):
Yeah.
Speaker 1 (04:40):
One millirem is equal to 0.00001 sieverts. Okay? Okay. You
get 20 millirems from a chest X-ray. He got 17
sieverts all at once. Wow. I mean, that's just such
a mind-boggling amount of radiation that I can't believe he
(05:02):
didn't die immediately. I say we take a break and
come back and talk about Ochi's agonizing 83 days of
life that followed that radiation exposure. All right.
Speaker 2 (05:12):
We'll be right back.
Speaker 1 (05:36):
So, Chuck, before we broke, I was saying I was
surprised that he didn't die immediately.
Speaker 2 (05:40):
Yeah.
Speaker 1 (05:40):
The reason he didn't die immediately is because it takes
a little while for the incredible damage that the radiation
did to his body to actually take effect. But what
it did, essentially, was it blasted through every cell in
Hisashi Oichi's body and damaged the DNA inside so much
(06:02):
so that the doctors caring for him said that he
had completely, or the radiation had completely shattered his chromosomes.
The actual packets that hold the DNA in your cells
were just shattered. They couldn't find chromosomal structures throughout his
body that weren't just totally messed up.
Speaker 2 (06:24):
Yeah, we should mention there were three guys in the
immediate area. He was the one closest to the tank.
There was another guy a little less close to the tank.
And then I guess the third guy even less close
to the tank. Ouchi was taken to a local hospital
at first, obviously, like very quickly, and then transferred to
the National Institute of Radiological Sciences in Chiba, but then
(06:46):
eventually would end up at the University of Tokyo Hospital
for some really extensive specialized treatment. Specialized meaning like they
had no roadmap for this. So they were kind of
trying anything.
Speaker 1 (06:59):
Exactly. they got in touch with his sister who was like, hey,
he is not really able to produce new white blood cells. Basically,
any fast-growing, fast-regenerating cell, it took the damage the most.
And that's where it showed up first because those are
the cells that are dividing. And now that their DNA
(07:20):
is messed up, they're dividing in all sorts of terrible ways.
So the things that made up like the lining to
his gut, those fast-dividing cells, they started to show problems first.
His skin... And then his bone marrow that produces white
blood cells, red blood cells, all sorts of really important stuff.
That was probably the biggest problem because he was very
(07:43):
vulnerable to infection without a bunch of white blood cells
or not producing correct ones anymore. So they went to
his sister and said, hey, can you donate some bone marrow?
And she did. Yeah.
Speaker 2 (07:54):
So, you know, like I said, they were trying blood
transfusions at first, stem cell transplants. And that's where his
sister came into play. And initially, it showed like that
transplant produced some new white blood cells. But very quickly,
they started getting damaged and, you know, basically in the
(08:15):
same way. He was just so riddled with it. And
his skin and his intestinal lining couldn't regenerate normally. He
had to constantly get fluids like replaced all throughout his body.
He was on respiratory support. and like organ failure started
to set in. Yeah.
Speaker 1 (08:34):
So the guy who was second closest when that radiation
blast went off, his name was Masato Shinohara. And he
died from his injuries in 2000, April 2000. But about
four months before, on December 21st, 1999, Hisachi Ouchi died
at the University of Tokyo Hospital. And it had been
(08:56):
83 days since he had undergone that blast of radiation.
And so, of course, this made really big news around
Japan and around the world. This is nuts that anybody
even lasted that long, let alone just the grisliness of
the whole thing. So everybody was like, how did this
happen at all? And they started looking at JCO. It
(09:17):
turns out JCO was a terrible, terrible company that had
no business doing something as important and dangerous as nuclear
fuel production.
Speaker 2 (09:29):
Yeah, for sure. That third worker survived, by the way,
out of the three. But yeah, JCO had allowed a
lot of shortcuts to happen. Like you said, the instructions
just for this were that wasn't the approved procedure. There
was not a lot of regulatory approval going on. The
workers didn't have safety training that they needed. The facility
(09:51):
didn't have a critical incident alarm, which is crazy. They
just I guess they thought that like there wouldn't be
that kind of accident there.
Speaker 1 (09:59):
That's what happened at Three Mile Island. Hubris.
Speaker 2 (10:01):
Yeah, that's right. That same thing. They also weren't conducting
the kind of inspections routinely that they needed to. And
that might have turned up like, hey, this process that
we're using is like really unsafe and we should be
using the approved process.
Speaker 1 (10:13):
So I just want to point out, I think it's
probably clear, but I just want to make 100 percent clear.
These three workers were not taking their own shortcut. They
were doing the procedure that their company was telling them to,
which was a dangerous shortcut. So the dangerous shortcut was
official company procedure. Right. Yeah.
Speaker 2 (10:32):
So as far as the official like procedure. blame or whatever,
the International Atomic Energy Agency said it was human error
combined with serious breaches of safety principles. For JCO's part, they,
in 2003, six of the officials got suspended prison sentences
for professional negligence. The company was fined and they couldn't,
(10:54):
they had shut down the plant, didn't they?
Speaker 1 (10:57):
They did. They would think it was the first time
ever that a company lost its license to, to, enriched
nuclear fuel in Japan. Yeah. And then also they were like,
you know, these safety inspectors that didn't do the proper
inspections that were to turn up that issue with the
different procedure, they fell down too. So Japan really kind
(11:18):
of bulked up its nuclear stuff and now everything's great. Yeah.
Speaker 2 (11:23):
I mean, you know, it exposed like what could happen.
And I think with every time we do something like this,
like It's like they're very sad stories, but it seems
like they come out on the other side with like,
all right, now we're trying to do it right. Don't
you think?
Speaker 1 (11:37):
Yeah, I think because in this case, JCO maybe wasn't
powerful enough to try to fight having to change. So
it did end up for the best.
Speaker 2 (11:46):
Yeah.
Speaker 1 (11:47):
Yeah. Anything else?
Speaker 2 (11:48):
I got nothing else.
Speaker 1 (11:49):
Well, I say you give it to him.
Speaker 2 (11:52):
Short Stuff is out. Stuff You Should Know is a
production of iHeartRadio. For more podcasts from iHeartRadio, visit the
iHeartRadio app, Apple Podcasts, or wherever you listen to your
favorite shows.
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