The Minamata Bay pollution disaster in Japan from 1932 to 1968 exposed local residents to methylmercury released as a byproduct of a chemical plant. Over time, residents developed neurological symptoms and the cause was traced to eating fish and shellfish contaminated with mercury from the plant's wastewater. While the company denied responsibility, over 2,000 victims were eventually certified with more receiving compensation. Decades later, protests and media coverage helped bring awareness and democratization around the environmental and human impacts of industrial pollution.

1. THE MINAMATA
DISEASE DISASTER
(水俣病の災害) 1932 TO 1968
By: John Paul Espino
De La Salle University – Dasmarinas
Facebook.com/Johnpaul.dss

3. FIRST THE CATS
AND FISHES HAD
GONE WILD, THEN
THE ISLANDERS
BEGAN TO DIE
A unique and deeply – Felt Feature.
Documentary and Report on Pollution

4. What is it?
• Minamata Disease is also
known as “Chisso-Minamata
disease”, it is a disease of the
central nervous system, a
mercury poisoning caused by
consumption in large amounts,
of fish and shellfish from
Minamata Bay.

5. • The causative agent is
methylmercury produced in
the acetaldehyde acetic acid
facility of Shin Nihon Chisso's
Minamata factory.

6. Symptoms • Ataxia (lack of muscle coordination on
voluntary movements)
• Numbness in hands and feet
• Loss of peripheral vision
• Damage to hearing and speech
• In extreme
cases, insanity, paralysis, coma,
and death follow within weeks of the
onset of symptoms.
• A congenital form of the disease can
also affect fetuses in the womb.

9. Origin
• Minamata is a city
located in Kumamoto
Prefecture, Japan. It is
on the west coast
of Kyūshū and
faces Amakusa islands.
• Minamata was
established as a village
in 1889 then grew into a
city in 1949.

10. Origin
• Minamata Bay is a bay on the
west coast of Kyūshū island and
part of the larger Shiranui Sea.
• The coastline has many inlets
and coves which act as the
spawning grounds
of fish and shellfish.

11. Origin
• In 1908, Chisso Corporation opened
a chemical factory near the bay .
• Chisso Corporation is once a
fertilizer and carbicle company, then
advanced to a petrochemical and
plastic-maker company.

12. History
1908
The Chisso
Corporation first opened a
chemical factory in
Minamata in 1908. Initially
producing fertilizers but as
the company grew larger.

13. History
they started manufacturing
acetaldehyde to produce
plastics. In process of
manufacturing,
methylmercury were used.

14. FirstVictims
1956
• April 21, 1956, a 5 year-old
girl was examined at
the Chisso Corporation's
factory hospital
in Minamata, Kumamoto.
• The physicians were puzzled
by her symptoms: difficulty
walking, difficulty speaking,
and convulsions.

15. FirstVictims
1956
• Days later, her younger sister and
their neighbor's daughter also began
experiencing similar problems. After
a house-to-house investigation, 8
more patients were discovered and
hospitalized.
• May 1956, the hospital director
reported to the local public health
office the discovery of an "epidemic
of an unknown disease of
the central nervous system“,
marking the official discovery of
Minamata disease

16. SCHEME OF HOW THE
METHYL MERCURY
COMPOUND IS TRANSMITTED
FROM THE ACETALDEHYDE MANUFACTURING PROCESS
TO THE HUMAN BODY

19. Finding the
Cause
• Researchers from Kumamoto University found that
the staple food of victims was
invariably fish and shellfish from Minamata Bay.
• The cats in the local area, which tended to eat scraps
from the family table, died with symptoms similar to
those discovered in humans. This led the researchers to
believe that the outbreak was caused by some kind
of food poisoning, with contaminated fish and shellfish
being the prime suspects.
• November 4, 1956 the research group announced its
initial findings: "Minamata disease is rather considered
to be poisoning by a heavy metal, presumably enters
the human body mainly through fish and shellfish.”

20. Identification of Mercury
• Chisso was immediately suspected as the tests
revealed that its wastewater contained many
heavy metals in concentrations sufficiently high
to bring about serious environmental
degradation. These
includes: lead, mercury, manganese, arsenic, thal
lium, and copper, plus the chalcogen selenium.
• At first, manganese was thought to be the causal
substance due to the high concentrations found
in fish and the organs of the deceased.

21. Identification of Mercury
• March 1958, British neurologist Douglas
McAlpine suggested that Minamata
symptoms resembled those of organic
mercury poisoning, so the focus of the
investigation centered on mercury.
• Methylmercury([CH3Hg]+), is an organic
mercury and is a white powdery substance
that smells like the sulfur in a hot spring. It
is easily absorbed from the stomach then
also to the brain where it is concentrated
and causes great damage to the human
body.

22. Response of Chisso
1959
• Knowing that they were the prime suspect in Minamata
Disease, Chisso changed their wastewater output route
to deflect criticism.
• from September 1958, instead of discharging its
wastewater into Hyakken Harbour (the focus of
investigation), they discharged wastewater directly into
Minamata River.
• The immediate effect was the death of fishes and new
Minamata disease victims began to appear in other
fishing villages up and down the coast of the Shiranui
Sea, as the pollution spread over an even greater area.

23. Compensation of
fishermen and
patients, 1959
• The Minamata Fishing Cooperative managed to win small payments of
"sympathy money" from the company but after the outbreak of
Minamata disease, the fishing situation was becoming more and more
critical.
• The fishing cooperative protested againstChisso and forced their way
into the factory onAugust 6 and 12, demanding compensation.
• August 29, the fishing cooperative agreed to the mediation committee's
proposal arranged by Minamata MayorTodomu Nakamura.The
company paid the cooperative ¥20 million and set up a ¥15 million fund
to promote the recovery of fishing.

24. Wastewater
treatment
• Chisso was ordered to switch back its
wastewater drainage from the Minamata
River to Hyakken Harbour and to speed up
the installation of wastewater treatment
systems at the factory.
• Chisso installed a Cyclator purification
system. Chisso's president Kiichi
Yoshioka even drank a glass of water
supposedly treated through the Cyclator to
demonstrate that it was safe.

25. Wastewater
treatment
• The wastewater from the acetaldehyde
plant which still contained mercury was
not treated through the Cyclator at the
time and the company knew about it.
• Testimony at a later Niigata Minamata
disease trial proved that Chisso knew the
Cyclator to be completely ineffective: "The
purification tank was installed as a social
solution and did nothing to remove organic
mercury.”

26. Outbreak of Second
Minamata disease
1965 – Nigaata Minamata Disease
• Minamata disease broke out again and this
time along the banks of the Agano
River in Niigata Prefecture.
• The Showa Electrical Company, owned by
Showa Denko, employed a chemical plant
process using a mercury catalyst very similar
to that used by Chisso in Minamata.

27. Outbreak of Second
Minamata disease
• Researchers from Research Group and Hajime
Hosok Kumamoto University awa (who had
retired from Chisso in 1962) used their
experience from Minamata and applied it to the
Niigata outbreak. Similar to Minamata, they’ve
seen cats living along the banks of the Agano
River go mad and die, and patients appeared
with identical symptoms
• September 1966, a report was issued proving
Niigata's wastewater to be the cause of this
second Minamata disease.

28. Response of
Showa Denko
• They discredited the
researchers while proposing
their own theory. The company
issued information leaflets that
rejected their wastewater as
the cause of the disease and
blamed the "agricultural
chemical run-off" that entered
the river after the 1964 Niigata
earthquake.

29. Official government recognition
• 1959–1969 - The years between the
first set of "sympathy money"
agreements and the first legal action
taken against Chisso are often called
the "ten years of silence". There
were no significant impact on the
actions of the company or the
coverage of Minamata in the
national media
• In May 1968, Chisso finally stopped
using mercury catalyst in the
production of acetaldehyde.

30. Official government recognition
• September 26, 1968, 12
years after the discovery
of the disease, the
government issued an
official conclusion that cause of
Minimata disease is the causative
agent methylmercury produced in
the acetaldehyde acetic acid facility
of Shin Nihon Chisso's Minamata
factory was discharged in factory
wastewater.”

31. Epidemiology
• Full epidemiological study has never been
conducted and patients were recognized only if
they voluntarily applied to a certification council
to seek financial compensation.
• Over 17,000 people from Kumamoto and
Kagoshima prefectures have applied for
certification as Minamata disease victims. Of
these, 2,264 victims have been officially certified
(1,408 of whom have died) and over 10,353
people have received financial compensation
from Chisso. Therefore, 12,617 people have been
officially recognized as patients affected by
mercury.

32. Treatment to Minamata Disease
• No fundamental cure for Minamata disease
has yet been discovered, so treatment consists
of attempts to lessen the symptoms
• The most important aspect of treatment is the
removal of mercury from the body using
chelating agents.
• Loss of muscle function and paralysis are
common in patients so physical rehabilitation
helps patients regain some amount of control
over mobility.
• In some cases, patients may suffer from
convulsions in which case doctors will
prescribe anticonvulsant drugs.

33. “THE PAST BECOMES A
TEXTURE, AN AMBIENCE
TO OUR PRESENT.”
THE PRESENT
MINAMATA
(今日の水俣)

34. • What has happened to chisso?
• What has happened to
minamata bay?
• What have the patients been
requesting?
• Democratizing effects
• Society and culture
THE PRESENT MINAMATA
(今日の水俣)

35. • What has happened to Chisso?
- Chisso has its head office in Tokyo and is still an important company in Minamata.
Chisso owes enormous debts being the culprit of Minamata disease. From 2000-2003, the
company also reported total compensation liabilities of over US$170 million. Their 2004
Annual Report however reports an equivalent of about US$50 million in "Minamata
Disease Compensation Liabilities“.

36. • What has happened to Minimata
Bay?
- The sludge in Minamata Bay with
a mercury content above 25 ppm was
dealt by Kumamoto prefecture by
dredging and reclamation. 58 hectares
of reclaimed land was created in
Minamata Bay. In order to prevent the
spread of polluted fish, nets were
placed around Minamata Bay and
enlisted the fishing cooperative to catch
fish in the bay. These fish were then
bought and disposed of by Chisso. By
July 1997, the Minamata Bay has been
declared safe and the nets around the
bay were removed.

37. • What have the patients been requesting?
-More than 60 years have passed since Minamata
disease broke out. These have been 60 years of
continuous hardship and strife for the patients. What
the patients sought through the government and
Chisso was a heartfelt and sincere apology and
acceptance of responsibility for causing Minamata
disease and neglecting the patients. What they most
strongly appealed for during this period of isolation
from the local society was that they be treated as
human beings and as citizens of Minamata. The
patients of Minamata disease ask us not to forget
those who were sacrificed in our search for material
prosperity and the destruction of our ties to nature, and
to always consider what we should do in the future.

38. • Democratizing Effects
- According to Timothy George, the environmental protests that surrounded the disease appeared to
aid in the democratization of Japan. When the first cases were reported, the rights of the victims were not
recognized, and no compensation were given. Instead, the afflicted were ostracized from their community due
to ignorance about the disease. Through the evolution of public sentiments, the victims and environmental
protesters were able to acquire standing and proceed more effectively in their cause. The involvement of the
press also aided the process of democratization because it caused more people to become aware of the facts of
Minamata disease and the pollution that caused it.

39. • Tributes
-Toshiko Akiyoshi, touched by
the plight of the fishing village, wrote a
jazz suite, "Minamata" central piece of
his 1976 album on RCA, Insights .
-The song "The Disease of the
Dancing Cats" by the band Bush is also
in reference to the disaster.
- The prominent Japanese
filmmaker Noriaki Tsuchimoto made a
series of films, starting with Minamata:
The Victims and Their World and
including The Shiranui Sea,
documenting the incident and siding
with the victims in their struggle against
Chisso and the government

40. References
• https://en.wikipedia.org/wiki/Minamata_disease
• http://www.soshisha.org/english/10tishiki_e/10chisiki_
3_e.pdf