Japanese Prime Minister Shinzo Abe assured the International Olympic
Committee (IOC) on September 8, 2013 that radiation leaks at the
Fukushima Daiichi Nuclear Power Station were under control and did not
pose any health risks.
Speaking to the IOC meeting prior to the vote to
decide on the 2020 Olympics host city, Abe referred to this major issue
that had raised doubts about Tokyo's chances of holding the event.
"Let me assure you the situation is under control.
It has never done and will never do any damage to Tokyo," he stressed.
Meanwhile, the crippled Fukushima Daiichi Nuclear
Power Station is producing massive amounts of radioactive water that
are flowing into the ocean every day. The plant operator, Tokyo
Electric Power Company (TEPCO), has also admitted that the radiation
leaks are not fully contained within the nuclear power plant harbor.
The nuclear power plant workers, local fishermen and
many other citizens were shocked to hear the prime ministers’ totally
groundless comment, voicing criticisms and anger. In addition to the
buildup of contaminated water, troubles have emerged one after another
on the plant premises, such as sudden rises in radiation level in some
places and many incidents of workers receiving exposure to high-level
Did removal of rubble and wreckage cause worker body contamination?
It has been confirmed that the heads and hands of
ten TEPCO employees were exposed to radioactive substances when they
were leaving the Fukushima Daiichi Nuclear Power Station on August 12.
They were sprayed with water from the mist generator installed at the
plant for prevention of heat stroke. At first, the mist generator or
the water from the device was thought to be the source of the
On August 19, radiation levels of up to 13.3 Bq/cm2 (the government’s exposure criterion is 40 Bq/cm2)
were detected from the heads of two workers who had finished work and
boarded a bus outside the main earthquake-proof building. An
examination of dust collected from the air in front of the building
indicated that the radioactive cesium level had increased there.
TEPCO announced on August 29 that the radiation
exposure of the 12 workers waiting for a bus in front of the
earthquake-proof building on August 12 and 19 is believed to have been
caused by scattered radioactive substances generated by two operations
being carried out on top of the Unit 3 reactor building, some 400
meters southeast of the earthquake-proof building. One of the
operations was the removal of a bridge-type crane for carrying nuclear
fuel, which was conducted on August 12, and the other was the rubble
and wreckage removal operation carried out at the same location on
August 19. On both days, winds were blowing from the reactor building
toward the earthquake-proof building. It is said that the removal
operations were being carried out while the alarm was sounding. In
addition, while the workers were waiting for the bus, the alarm on the
radiation counter installed in front of the earthquake-proof building
was also said to have been sounding, indicating that the radiation
levels in those places were high.
Internal exposure levels of plant’s workers engaged in emergency operations
Pressed by international organizations, the health ministry has re-evaluated worker internal exposure levels
The Ministry of Health, Labor and Welfare (MHLW)
announced on July 5 that it had revised the internal exposure records
for 479 workers engaged in emergency operations at the plant. According
to the ministry, some of the data recorded in TEPCO’s reports were not
correct. The reports were compiled based on data from the plant makers
and other subcontractors.
The ministry said it had checked closely the FY2011
and FY2012 reports on the internal exposure levels of the workers which
were submitted to the ministry by TEPCO at the end of April, and
discovered that there were some discrepancies between the exposure
levels assessed by the subcontractors and those provisionally assessed
by the utility company. The ministry, therefore, launched a
re-assessment of the records in May.
Of the 19,592 workers engaged in the emergency
operations at the plant between March 11 and December 2011, 452 were
exposed to higher amounts of radiation than recorded levels, with the
largest gap reaching 48.9 millisieverts (mSv), the ministry said.
After the correction was made by the end of March
2013, the number of workers whose total dosage topped 50 mSv increased
by 24 (of these, six were exposed to more than 100 mSv).
Although the official limit of the plant worker’s
five-year exposure to radiation is set at 100 mSv, at least two of the
above-mentioned workers were confirmed to have continued to work after
that period without knowing that their total dosage had exceeded the
Immediately after the nuclear accident, there was a
serious shortage of whole body counters for measuring internal exposure
to radiation, and many workers were unable to check their dosage for
several months. In such cases, the calculation of the total internal
exposure is generally done by taking into account the current dose and
the length of time since the worker began absorbing radiation.
The ministry’s investigation has revealed many
questionable cases. For example, a case in which the exact time when
the worker began absorbing radiation was not known, but was recorded as
the middle of the March-December period. The general rule is to regard
the starting time as the time when the worker began working in a
In other cases, input errors of the data for 29
workers, mixed-up data, and other types of mistakes were discovered. As
a result, a total of 479 errors and mistakes were found in the records
for a total of 19,346 workers, the ministry said.
In July 2011, the Nuclear and Industrial Safety
Agency ordered TEPCO to clarify the dosage calculation rules but the
plant operator failed to fully comply with the order. Later, some
scholars and intellectuals warned that the dosage calculation would be
made inappropriately if TEPCO did nothing about it, but the utility
completely failed to look into the matter.
Pressed by the international organizations probing
into the harmful effects of radiation exposure, TEPCO submitted data on
age-specific doses of the workers with distribution charts of their
internal-exposure and thyroid equivalent doses to the World Health
Organization in March 2012. Earlier this year, some of the
international organizations posed questions about data in the report,
which prompted MHLW to launch its investigation into the matter.
Most of the internal exposure of the workers was
thyroid exposure to radiation suffered immediately after the nuclear
accident. Concerning the thyroid equivalent doses, TEPCO reported the
data for 522 workers calculated with the use of their actual
measurements of exposure to iodine 131. Of these workers, the doses of
178 workers exceeded 100 mSv, the report said.
This time, TEPCO expanded the scale of its survey,
and when the worker’s exposure to iodine 131 was not clear, it
calculated their doses based on the worker’s exposure to cesium. The
result of this survey showed that as many as 1,973 workers suffered
high-level exposure of more than 100 mSv.
Since March 11, 2011, CNIC has been holding
negotiations with the government’s ministries and agencies concerned
through various channels, in cooperation with many other organizations,
such as the Japan Occupational Safety and Health Resource Center and
Radiation Exposure Opposition Campaign.
As for the issue of nuclear power plant workers’
exposure to radiation, we negotiated with the government officials for
the tenth time on June 20.
Since the outset of the negotiations, we have
maintained that TEPCO conducted appropriate dosage assessments only for
its own heavily-exposed employees, but did not do so for
heavily-exposed workers hired by its subcontractors and cooperating
We have repeatedly demanded during the past two
years that the ministry clarify the methods of dose calculations
adopted by TEPCO’s subcontractors and cooperating firms. The ministry
finally launched its action to investigate the matter, not in response
to our demand, but in surrender to pressure from the international
organizations. Their stance concerning this problem is, therefore,
The recent re-investigation of internal exposure has
covered the workers of plant makers and companies specializing in
nuclear plant work, as well as temporary officials employed by TEPCO.
However, there were other workers engaged in emergency operations who
were exposed to high-level radiation, such as the security guards who
continued to guard the front gate immediately after the outbreak of the
nuclear accident and at the time of the explosion in the reactor
buildings. They probably had no time to take rests or eat meals in
other places for several days. The ministry should conduct sufficient
hearings on such people and re-assess their doses correctly.
TEPCO’s policy of recording only doses above 2 mSv
in the radiation exposure management notebook and omitting smaller
doses is not justifiable.
An official of the Industrial Health Division of
MHLW’s Labor Standards Bureau in charge of health protection measures
for workers exposed to ionizing radiation said the ministry is
conducting assessments of worker internal exposure levels once every
three months, screening doses of more than 1 mSv to find out if the
total exposure level exceeds 20,000 cpm. The exact number of counts is
actually kept, but counts of less than 2 mSv are recorded as “zero” in
the official radiation-exposure management notebook, he said. “In the
International Commission on Radiation Protection’s general rules
concerning protection of workers from radiation, entitled ICRP pub.75,
there is a rule that excludes counts of less than the designated level,
and we are following the rule.”
Published in 1997, the ICRP pub.75 did not foresee
disastrous accidents at nuclear power plants that could not be settled
for several years, such as the one that has occurred in Fukushima.
It is extremely important to have a correct record
of internal exposure levels of the workers engaged in various
operations at the plant where radiation leaks continue. The internal
exposure problem is becoming more and more serious for the workers
engaged in the tasks of decontamination and disposal of radioactive
Management of radiation exposure data for decontamination workers
There is also the deplorable situation where the
employers of decontamination workers are not sending worker radiation
exposure data to the Radiation Effects Association (REA) Radiation Dose
Registration Center (RADREC), a public interest incorporated foundation
for registration and management of exposure doses. This means that the
decontamination workers working under new employers are not informed of
their cumulative doses. Some exposure-dose records can be lost if an
employer goes bankrupt. Without such data, decontamination workers will
have difficulties in applying for workers’
The seventh negotiation with the government was held
on June 24 jointly with eight other organizations and groups, such as
the Radiation Exposure Opposition Campaign. The discussion was based on
the statement calling for “the protection of health and lives of
workers and residents, and compensation for health damages caused by
In this negotiation, MHLW expressed its position
that it is desirable for decontamination business operators to promptly
register their worker radiation exposure data with the RADREC, a
private database, as soon as their doses are confirmed, though it is
not mandatory. The ministry said this in response to the question
raised prior to the negotiation about the unified management of
exposure data for emergency operation workers at the Fukushima nuclear
In this negotiation, the Environment Ministry
official said, “After five years, the dosage data can be handed over to
the designated organization. In this case, the employers will be
released from the duty to keep the data for the remaining 25
years.” “However, in the case of the Decontamination Ionizing
Radiation Ordinance, there are no such rules and the employers cannot
hand over their workers’ dosage data to other organizations. If MHLW,
which has expertise in the Industrial Safety and Health Act, makes such
rules, we will follow them,” said the ministry official.
We feel that MHLW should take the initiative in safety management of decontamination workers.
(Mikiko WATANABE, CNIC)
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