保健医療科学

2018Vol.67 No.1 p.84－92

Topics: Lessons learned on public health from the Fukushima Daiichi Nuclear Power Plant accident＜ Review ＞
Lessons learned from radiation protection for emergency
response and remediation/decontamination work relating to
the Fukushima Daiich Nuclear Power Plant accident in 2011
Shojiro Yasui
Ministry of Health, Labour and Welfare
Abstract
This article reviewed the papers which address issues of radiation protection for emergency workers
and decontamination workers relating to the Fukushima Daiichi Nuclear Power Plant accident in 2011.
The papers were published from 2012 to 2017 and they extracted lessons learned from the experiences
and provided guidance regarding future preparedness for a similar accident. Numerous reports have been
published about the accident. However, the issues regarding the radiation protection of workers haverarely been presented. The reviewed papers provide detailed information on the problems substantiatedby reliable primary sources. The article is not arranged chronologically but divided into four broad topics:(a) emergency responses for radiation protection and health care, (b) post emergency responses, (c)establishment of new regulations for decontamination/remediation, and (d) the epidemiological study on
health effects of radiation exposure.
keywords: radiation protection, Fukushima nuclear accident, emergency response(accepted for publication, 13th November 2017)

I．Introduction
In response to the Fukushima Daiichi Nuclear Power
Plant accident that resulted from the East Japan Earthquake
on March 11, 2011, the Tokyo Electric Power Company(TEPCO) under took emergency work to which an
emergency dose limit applied [1]. The Japanese government
increased the emergency dose limit from 100 mSv to 250
mSv exclusively for the emergency work performed at theaffected plant from March 14 to December 16, 2011.
During the emergency work, TPECO and the Japanese
government experienced various problems in management,
control and reduction of radiation exposure, and medical
and healthcare management for emergency workers. For
the proper implementation of radiation protection andhealthcare management, the Ministry of Health, Labour andWelfare (MHLW) issued a series of compulsory directives
and administrative guidance to TEPCO.

In the post-emergency situation, the MHLW conducteda fact-finding survey in response to the manipulation of
personal alarm dosimeter collection efficiency. The survey
provides the lessons learned about post-emergency
radiation protection at the affected plant. Also, the MHLW
conducted a re-evaluation of a committed effective
dose of emergency workers for unifying the evaluation
methodologies employed by TEPCO and the primarycontractors.
Furthermore, to rehabilitate the areas contaminatedby the radioactive substances released from the affected
plant, the government of Japan decided to carry out
decontamination work (e.g., cleanup of buildings andremediation of soil and vegetation) and to manage the waste
resulting from the decontamination and unmarketablecontaminated goods. To prevent radiological hazards,
the government needed to provide sufficient radiation
protection for the decontamination workers.

Corresponding author: Shojiro Yasui
1-2-2 Kasumigaseki, Chiyoda-ku, Tokyo, 100-8988, Japan.
E-mail: syasui@st.rim.or.jp

84

J. Natl. Inst. Public Health, 67 (1) : 2018

Lessons learned from radiation protection for emergency response and remediation/decontamination work relating to the Fukushima Daiich Nuclear Power Plant accident in 2011
As for examining the health effects of radiation exposurefor emergency workers, the MHLW has formulated a
research team and implemented a study since 2014 using
the recommended study design drawn from meetings ofexperts.
This article reviewed the papers which address issuesof radiation protection for emergency workers anddecontamination workers since the Fukushima nuclear
power plant accident in 2011. The papers were publishedfrom 2012 to 2017 and they extracted lessons learned fromthe experiences and provided guidance regarding futurepreparedness for a similar accident. The article is divided
into four broad topics: (a) emergency responses for radiation
protection and health care, (b) post emergency responses,(c) establishment of new regulations for decontamination/
remediation, and (d) the MHLW-sponsored epidemiologicalstudy on health effects of radiation exposure. The article
describes problems that occurred and provides discussions
on the lessons learned from the responses to the issues.

II．Methodology
Papers on radiation protection of workers involvedin the accident have rarely been published in academic
journals whereas numerous reports have been published
about the accident itself. Most of the studies concerning
workers’ radiation protection were written by officers of
the government and research institutions which conductedradiation dose evaluations or provided medical care for
emergency workers, including the Japan Atomic Energy
Agency, the National Institute of Radiological Sciences, theUniversity of Occupational and Environmental Health, andthe National Defense Medical College. This is probably
because collecting data has been challenging for researchers
because the information on radiation exposure and healthcare of emergency workers is regarded as personal
information and access to the data is limited to specificauthorities. Furthermore, gaining access to emergency
workers has also been difficult because their workplaces
were in restricted areas and their identities were notdisclosed.
The official governmental reports provided limited
information about workers’ radiation protection and healthcare. The report of the Japanese government's Investigation
Committee on the Accident at the Fukushima Nuclear
Power Stations in 2012 rarely prescribed the issues ofworkers’ radiation protection[2]. The report of the National
Diet of Japan Fukushima Nuclear accident Independent
Investigation Commission in 2012 specified the issue ofworkers’ radiation protection in only eight pages out of 586
pages[3]. This is because both committees focused on theissues surrounding the causes of the accident.
International organizations also published many reports
concerning the accident. Unlike the reports of the Japanesenational committees, they covered the issues of radiation
protection and health consequences for workers in
substantial volumes. The reports published by World HealthOrganization (WHO) in 2012 and 2013[4,5] mainly focusedon the health effects of radiation exposure to the generalpublic and the emergency workers involved. The reportassessed the potential health consequences of exposure
to radiation of the emergency workers assuming four
scenarios that describe different exposure patterns. The
reports stated that “the relative increase over backgroundfor leukemia and thyroid cancer is as high as 28% in theyoungest workers” for less than 1% of workers, and “anotable risk of thyroid cancer is estimated, especially foryoung workers” for those few emergency workers who
received very high doses to the thyroid. (p. 93 in[5]) WHO
made the evaluations based on the exposure data provided
by TEPCO.
The report of the United Nations Scientific Committee
on the Effects of Atomic Radiation (UNSCEAR) publishedin 2013[6] indicated the health consequences of workers
as “No radiation-related deaths or acute diseases had been
observed among the workers and general public exposed
to radiation from the accident.”(p. 10 in [6]) As for “the12 workers … who were estimated to have received
absorbed doses to the thyroid from iodine-131 intake alone
in the range of 2 to 12 Gy, an increased risk of developing
thyroid cancer and other thyroid disorders can be inferred.”
Besides, “more than 160 additional workers received
effective doses currently estimated to be over 100 mSv”,
however, “any increased incidence of cancer in this group is
expected to be indiscernible.” (p. 11 in [6])In report, the UNSCEAR conducted an independent
evaluation of radiation dose data provided from TEPCO.
This report criticized primary contractors because “basedon the comparative assessments carried out, the Committee
was unable to confirm the reliability of the internal
exposure assessments reported by contractors for theirworkers.”(p. 73 in [6] ) This criticism arose because the
UNSCEAR did not use the standard diplomatic channels of
the Japanese government but directly requested TEPCO toprovide exposure data. These data were incomplete because
TEPCO provided only the exposure data it possessed andnot all the data of the primary contractors. Furthermore,
TEPCO could not provide sufficient information about themethodology of internal exposure evaluation employedby the primary contractors. As background, the disclosed
information about workers’ exposure data from the Japanese
government was limited and insufficient.

J. Natl. Inst. Public Health, 67 (1) : 201885

Shojiro Yasui
For strengthening international communication, the
MHLW translated all disclosed information concerning
workers’ radiation protection into English and put iton the Ministry’s new website established in 2012 [7].
Regarding the internal dose evaluation, the MHLW
conducted two governmental re-evaluations of internal
dose for unifying methodologies employed by TEPCO
and primary contractors in July 2013 and March 2014; andpublished the results on the Ministry’s website [8,9]. In
response to criticism from UNSCEAR for a lack of reports
published in academic journals, an officer of the MHLW –the author of this review – published 12 studies from 2013
to 2017 concerning the major topics of workers’ radiation
protection.
The report published by International Atomic Energy
Agency (IAEA) in 2015 [10] mentioned not only healtheffects of radiation exposure of workers, but also provided
much information concerning workers’ radiation protection.
The completeness of this report was due to the Japanese
government dispatching several experts to the IAEA andproviding sufficient relevant information from TEPCO andJapanese government.
This review mainly examined academic papers referred
to in the reports of the WHO, UNSCEAR and IAEA.
Because of the nature of a review, press release documentsof the Japanese government, such as the MHLW, and of
TEPCO were not examined. Records of the press release
documents are referred to in the reviewed papers. As an
exception, the booklet which summarized the actions takenby the MHLW, published in 2013, was included in thisreview.

III．Emergency responses for radiation protection and health care management
1. Radiation protection problems
During the emergency work, the MHLW observed thefollowing radiation protection problems [11,12].
(a) Inappropriate Exposure Monitoring because of a Shortageof Personal Dosimeters: The tsunami damaged a large
number of electronic personal alarm dosimeters(PADs). The surviving dosimeters could not berecharged because of the electrical blackout at thesite. The number of usable dosimeters decreased toapproximately 320 on March 15, 2011, whereas thenumber of emergency workers increased progressively.
Under these circumstances, from March 15 to March 31,
2011, TEPCO could not supply PADs to all workers but
only one dosimeter for each work group who engaged
in outdoor works and the monitored exposure dose wasregarded as the common dose of the group.

86(b) Inappropriate Dosimeter Circulation Management andExposure Control: Given the breakdown of the electronic
exposure management system, TEPCO implemented
paper-based dosimeter circulation management at theaffected plant until April 4 (until June 8 in the support
facility known as J-Village). However, some workers
wrote down only their family names, and others wrote
in illegible characters. As a result, TEPCO faced the
difficulty of conducting a name-based aggregation ofdoses and a calculation of accumulated individual doses.
(c) Workers Who Were out of Contact: During the process ofthe name-based aggregation, on June 20, 2011, it was
revealed that several workers whose identities could
not be confirmed appeared on the circular list. The
number of workers who were not on the rosters reacheda maximum of 174.
(d) Delayed Internal Exposure Monitoring: After theaccident, TEPCO could not operate the whole bodycounters (WBCs) that were located in the affected plant
because of the increase of the background radiationlevel. In response, on March 22, 2011, TEPCO started
to operate two vehicle-mounted WBCs. However, thecapacity of the WBCs was insufficient to cover all of
the emergency workers. Furthermore, workers who
required identification of short-half-life radionuclides,
had to be dispatched to specialized institutions forevaluation of internal dose [13].
(e) Exceeding Emergency Dose Limits: The exposure dosesof six emergency workers had exceeded the emergency
dose limit (250 mSv), which the Japanese government
increased from 100 mSv on March 14, 2011.
(f) Internal Exposure That Resulted From the Inappropriate
Use of Protective Masks: Internal exposure beyond
record levels were repeatedly found until September,
2011, which was six months after the accident.
(g) Protection against Beta-Ray Exposure From Contaminated
Water: During the emergency work, several incidents ofbeta-ray exposure occurred in relation to contaminatedwater, such that workers received beta-ray exposureon their feet after they stepped into 30 cm deep
contaminated water while wearing half boots to installelectrical cables in a reactor building basement [14].
(h) Worker Training: From the time of the accident until
May 2011, TEPCO and the primary contractors
conducted training for newcomers to the affected plantfor only 30 min.
2. Medical and health care problems
During the emergency work, the MHLW observed thefollowing medical and health care problems [15].
(a) Implementation of Emergency Medical Examinations: In

J. Natl. Inst. Public Health, 67 (1) : 2018

Lessons learned from radiation protection for emergency response and remediation/decontamination work relating to the Fukushima Daiich Nuclear Power Plant accident in 2011
March 2011, the MHLW issued compulsory orders to
TEPCO to implement special medical examinations forscreening for acute radiation syndrome or local radiation
injuries every month. The implementation rate fromMarch to September rose gradually but remained low.
(b) Establishment of On-Site Medical Care Systems:
Although a few thousand emergency workers per day
continuously engaged in emergency work in the affected
plant, TEPCO could maintain the presence of physicians
and medical staff only during the daytime for a few days
each week during the early stages of the accident [1618].
(c) Patient Transportation from the Affected Plant: Threeof the five initial medical facilities were located in theevacuation zone and a hospital was located in the indoor
evacuation zone. At the other hospital, supply of waterand electricity were lost or malfunctioned [19,20]. Threedays after the accident, Fukushima Medical University
prepared to accept patients. However, the transfer fromthe affected plant took 3-4 hours.
(d) Prevention of Heat Illness: The MHLW was concernedthat heat illness could develop if emergency workers
spent long hours under the blazing sun while wearing
full-face respiratory masks and HAZMAT garments [21].
(e) Lodging and Food: During the emergent situation,
approximately 400 workers had to sleep on the floor of
the Seismic Isolation Building of the affected plant or
the gymnasium of the Fukushima Daini NPP, 13 km fromthe affected Fukushima Daiichi NPP. For the preventionof internal exposure, TEPCO restricted the food supply
to workers to boil-in-bag foods.
(d) Long-term Healthcare: For the long-term health care of
emergency workers, the action plan of the government
stated that a database should be constructed that could
track the radiation exposure of all emergency workers
long-term, including after retirement, and long-term
health care activities should be implemented for them
[7,18].

IV．Post emergency responses
1. Reduction of emergency dose limits
In response to the accident, on March 14, 2011, the
MHLW enforced an ordinance that temporarily increased
the radiation exposure dose limit allowed during the
emergency to 250 mSv. Subsequently, the MHLW
succeeded in reducing the emergency dose limit back to
the original limit through a phased approach [22]. In thefirst phase, the MHLW reduced the emergency dose limit
allowed for newcomers to the affected plant to 100 mSv
on or after November 1, 2011. On December 16, 2011, inthe second phase, the MHLW abolished the exemption
ordinance when STEP 2 in the emergency response plan,a cold shutdown condition of the affected nuclear reactors,
was completed.
2. Response to the manipulation of PAD collection efficiency
In December 2011, it was found a subcontractor had
demanded that its contracted workers cover their PADs
with 3-mm thick lead plates to lower dosimeter readings.
As a response, the MHLW conducted a fact-finding survey
to identify similar cases and devise measures to prevent a
recurrence of this incident [23]. The results of the survey
provide lessons that can also be applied to the transition
from emergency radiation protection to normal operation
given that the application of emergency dose limits ceasedon December 2011 in the affected plant.
3. Governmental re-evaluation of the committed effective dose
In April 2013, the MHLW noticed that significant
discrepancies were present between the committed
effective dose (CED) data provided by TEPCO and datareported by five primary contractors. Based on a reevaluation of the data, the MHLW required TEPCO and thefive primary contractors to readjust the CED data for 479
workers (2.5% of 19,346 emergency workers) [8]. Major
issues addressed during re-evaluation included a) selectionof the intake scenario, b) assumptions about the intake date,c) assessments of exposure to radiation from short half-life
nuclides, and d) assumptions of undetected 131I exposuredue to monitoring delay.
Furthermore, in January 2014, TEPCO learned that the
CED for nine emergency workers had been assessed using
a method other than the standard assessment methods
established by the MHLW in a re-evaluation conductedin July 2013 [9]. The MHLW requested that TEPCO andprimary contractors review all CED data for 6,245 workers
who were engaged in emergency work in March and April
2011 except those previously reviewed. New issues wereaddressed during the tertiary evaluation such as setting a
conversion coefficient between two different measurements
of internal exposure [24,25].

V．Establishment of new regulations for radiological protection for decontamination/ remediation work
1. Decontamination work and recovery and reconstruction work
Existing government regulations assumed that the

J. Natl. Inst. Public Health, 67 (1) : 201887

Shojiro Yasui
radiation sources were controlled and collected in indoor
restricted areas referred to as planned exposure situations.
The government had not considered the possibility ofa situation where radiation sources were scattered andworkers would have to deal with radioactive material
outdoors (referred to as an existing exposure situation).
ICRP recommendations state that exposure involving longterm rehabilitation of the contaminated areas should betreated as a part of planned exposure, although it does notprovide details regarding exposure management.
Given the insufficient international recommendations,
the MHLW decided to establish new regulations on
occupational radiological protection in an existing exposure
situation by using the protection in a planned situation as areference. During its deliberation, the MHLW employed thefollowing three principles [26,27]：(a) Ensure that the level of protection is equivalent to or
greater than the level in a planned situation and adhere
to existing regulations in a planned situation.
(b) Be practical and function smoothly in the situation
around the affected plant, which is limited by restricted
infrastr ucture, supplies and resources for thedecontamination work.
(c) Be consistent with the radiological protection for the
inhabitants around the work sites to avoid anxiogenic
effects because decontamination projects have to
be carried out in daily living areas, in full view of
inhabitants, unlike in the case of work in radiationcontrolled areas.

assess their past dose records at the time of employment.
However, cumulative doses may not be properly maintained
if a worker declares incorrect values for past doses.
In response, with facilitation by the MHLW, primarycontractors of decontamination work decided to establish
a central dose registration system [29]. The systemstarted its operation in December 2013 and provided dose
distributions in April and July 2015.

2. Disposal of contaminated soil and waste
Disposal of contaminated materials removed bydecontamination requires workers to engage in work
primarily conducted in indoor radiation-controlled areas.
The MHLW therefore applied the existing generalregulation for radiation protection to disposal workers.
However, those regulations were difficult to apply to thedisposal of decontamination-removed materials because thisinvolves the handling of huge amounts of materials, requires
large-scale facilities, involves fragmentation processes andlandfill operations, and includes operations that must be
conducted in high-ambient-dose-rate environments [28].
Thus, the MHLW decided to amend the general regulationand establish new prescribed radiation protections forworkers engaged in disposal of materials removed as part ofdecontamination work.

1. Lessons learned on radiation protection and healthcare management
The lessons learned described in [11,12] told that nuclear
operators need to make sufficient preparation to avoid
similar problems of radiation protection in the case of an
accident. The major points of those articles are as follows.
Sufficient measures and systematic preparation forradiological management should be ensured, including
the following: (a) Assistance from the power company's
corporate office or off-site support facilities outside anevacuation area is indispensable; (b) Primary contractors
should independently implement exposure management
operations for the employees of their subcontractors;(c) NPP operators should compile an operations manual,
stockpile personal protective equipment and PADs, andprepare emergency systems and whole body WBCs.
To reduce the exposure dose, the following lessons
should be shared: (a) To prevent internal exposure, it isnecessary to monitor the radioactivity concentration of
the indoor air of the workplace during an emergency, tostockpile and use appropriate respiratory protection and

3. Central dose registration system
The newly established regulations for radiation
protection of decontamination workers obligated employers
to monitor, record, and store workers' dose records and to88

VI．Epidemiological study on health effects
on emergency workers
Results from medical examinations of workers who
were engaged in emergency work in 2012 showed that theprevalence of abnormal findings was increased comparedwith that prior to the accident. The MHLW concluded
that the 2010 and 2012 data could not be easily comparedbecause 70% of the enterprises that reported the 2012
results differed from those that did so in 2010. However,the MHLW decided to implement a comprehensive
epidemiological study on the health effects of radiation
exposure on all emergency workers [30]. The scope ofthe study covers physiological effects in response to theobserved medical distresses and mental health problems[31,32]. The study team formulated and implemented thepilot study in 2014 and started the full-scale study in April
2015 with funding from a research grant from the MHLW.

VII．Discussion

J. Natl. Inst. Public Health, 67 (1) : 2018

Lessons learned from radiation protection for emergency response and remediation/decontamination work relating to the Fukushima Daiich Nuclear Power Plant accident in 2011
train newcomers how to use, fit and fit-test the respirators;(b) To prevent unnecessary beta-ray exposure, liquidproof garments should be mandatory when workers handle
contaminated water; (c) To reduce external exposure, it isindispensable to develop well-prepared work plans prior
to doing the work and to monitor the ambient dose rateof the work area to develop proper working procedures;(d) To promote the early deployment of remote-controlled
vehicles and the utilization of tungsten shielding vests for
reduction of exposure.
The lessons learned described in [15] told that theproper management and implementation of medical andhealth care management would require the following： (a)The government needs to assist in dispatching medical
staff to an affected plant; (b) Nuclear facility operators,
medical facilities and fire departments should make aprior agreement that clarifies the division of the roles
played in the event of an accident and they should conduct
emergency drills periodically with the full attendance ofrelated personnel to identify and resolve problems; (c)Operators need to develop a support base at a safe distancefrom the plant and to prepare to develop makeshift lodgingsin the case of an emergency; (d) Operators need to come toan agreement to share food stocks among closely locatednuclear plants and prepare cooking equipment that can beused in the case of an electrical blackout to provide warm
foods and drinks to as many workers as possible; (e) Boththe government and operators should conduct long-term
follow-up for emergency workers, including their healthcare system, medical examinations and mental healthconsultations.
2. Lessons learned on temporary increase of emergency dose limits
In the accident, the increase and subsequent reduction in
the emergency dose limit was initiated at the political level.
To avoid this intervention, the lessons learned describedin [22] showed that the government needs a pre-defined
protocol of the process and conditions to apply or amend
the emergency dose limit.
Regarding standard setting of emergency dose limits,
considering external exposures, the dose limit of 250 mSv
was sufficient to implement the necessary emergency
operations in response to this large scale nuclear accident
involving four nuclear reactors.
In the process of application of the dose limits, anapplication of a high-level emergency dose limit to all
workers without any exception was unavoidable in the earlystage of the accident. However, after the chaotic situations
were resolved, based on the principle of optimization, thegovernment should have established plural emergency

dose limits and applied them to specific work based on theurgency of the work and the ambient dose rate at the worksite.
3. Problems to be resolved in establishing new regulations in the existing exposure situation
1) Decontamination work and recovery and reconstruction work
It was problematic to determine how radiation protection
systems intended for planned exposure situations should
be applied to the existing exposure situation, because there
was no sufficient scientific basis. Lessons learned describedin [27] told that further research and development
concerning the following issues is warranted:(a) T h e r e l a t i o n s h i p b e t w e e n t h e r a d i o a c t i v i t yconcentrations of materials handled and the risk ofinternal exposure: The amended regulation requires
the use of appropriate personal protective garments
and masks, as well as internal exposure monitoringin accordance with exposure estimation, based on theradioactivity concentration multiplied by the density of
dust at work sites. However, there were no scientificexperimental data available to prove the validity of thisestimation.
(b) The relationship between the radioactive concentrationof the soil and the workers’ surface contamination level:
Experimental and empirical studies of this relationshipwould make it possible to establish a standard forwhen to require contamination screening. Further
development of this subject is warranted.
2) Disposal of contaminated soil and waste
For establishing new regulations, the lessons learned
described in [28] showed that two issues need further
considerations. The first was the balance between thecompeting goals of radiation protection and ensuring work
efficiency, which is necessary for the smooth disposal of 30
million tons of contaminated materials. The issue became
apparent in the discussion of radiation protection in landfill
operations for removed soil. The other issue was theapplication of regulations to conventional waste disposal
facilities, which were not originally designed to handle
radioactive substances.
4. Issues to be resolved for the epidemiological study
on health effects on emergency workers
The discussion about the basic study design of theepidemiological study described in [30] identified challenges
that could not be resolved and thus required further
consideration by the study researchers. The major issues
included: (a) study methods and target group, (b) evaluationof cumulative doses, (c) health effects (end points), (d)J. Natl. Inst. Public Health, 67 (1) : 201889

Shojiro Yasuicontrol of confounding factors, and (e) study implementation
framework. Identified key challenges that required further
deliberation were: (a) preventing arbitrary partisan analysis,(b) ensuring a high participation rate, (c) inquiry about the
medical radiation doses, and (d) the preparedness of new
analytical technology.
Based on the results of an open application, the MHLW
offered the grant to the Radiation Effects Research
Foundation as the study's controlling research institution.
Cooperating research institutions include the National
Institute of R adiation Sciences, the University ofOccupational and Environmental Health, Osaka University,
Jichi Medical University, Kanazawa Medical University, andthe Japan Atomic Energy Agency. The research team begana preliminary study in 2014, and started the full-scale study
from April 2015.

VIII．Conclusion“It was an unforeseen disaster.” The phrase wasrepeatedly used when officers of TEPCO and thegovernment talked about the accident. Emergency responseplans prepared before the accident mostly did not work. As
a result, TEPCO and the government needed to reconstruct
the accident management system while responding to theaccident through stop-gap measures.
Conversely, the accident has offered plenty of lessons
learned. The author hopes this review could explain thelessons learned for nuclear operators, governmental officials
and practitioners who are responsible for radiologicalprotection of workers and it could provide guidance
regarding future preparedness for a similar accident.

Conflict of Interest
The author has no affriliations with or involvement in any
organization or entity with any financial interest, or non-financial interest in the subject matter or materials discussed
in this article.

References[1] Yasui S. Radiation Protection for Fukushima 50: Lessons
learned from fukushima nuclear disaster. CreateSpace
Independent Publishing Platform; 2017; North
Charleston, South Carolina.
[2] Investigation Committee on the Accident at the
Fukushima Nuclear Power Stations. Final reportof Investigation Committee on the Accident at the
Fukushima Nuclear Power Stations; 23 July 2012. http://
www.cas.go.jp/jp/seisaku/icanps/eng/final-report.html

90(accessed 2017-11-12)[3] National Diet of Japan Fukushima Nuclear Accident
Independent Investigation Commission. Ch.4.4.5
Exposure of nuclear power plant workers. Reports of
the National Diet of Japan Fukushima Nuclear Accident
Independent Investigation Commission. Kuroda K, Ed.
National Diet of Japan. 2012. p.Ch4.100–Ch.4.106.
[4] World Health Organization. Preliminary dose estimationfrom the nuclear accident after the 2011 Great
East Japan Earthquake and Tsunami; World HealthOrganization, Geneva; 2012.
[5] World Health Organization. Health risk assessment
from the nuclear accident after the 2011 Great East
Japan Earthquake and Tsunami based on a Preliminary
dose estimation; World Health Organization, Geneva;
2013.
[6] United Nations Scientific Committee on the Effectsof Atomic Radiation. UNSCEAR 2013 Report Volume
I, Report to the general assembly Scientific Annex A;
United Nations, New York; 2013.
[7] Ministry of Health, Labor and Welfare. Response andaction taken by the Ministry of Health, Labor andWelfare of Japan on Radiation Protection for Workers
Involved in the TEPCO Fukushima Daiichi Nuclear
Power Plant Accident; 2 November 2013; Tokyo. http://
www.mhlw.go.jp/english/topics/2011eq/workers/tepco/
rp/irpw.pdf (accessed 2017-11-12)[8] Yasui S. Governmental re-evaluation of the committed
effective dose received by emergency workers
at the TEPCO Fukushima Daiichi NPP Accident.
Journal of Occupational and Environmental Hygiene.
2015;12(5):D60-D70.
[9] Yasui S. Tertiary evaluation of the committed effective
dose of emergency workers that responded to the
Fukushima Daiichi NPP accident. Journal of Occupational
and Environmental Hygiene. 2017;14(6):D69-D79.
[10] International Atomic Energy Agency. The Fukushima
Daiichi accident. Vienna: International Atomic Energy
Agency; 2015.
[11] Yasui S. Lessons learned: Radiological protection for
emergency workers at the TEPCO Fukushima Daiichi
APP (Part 1). Journal of Occupational and Environmental
Hygiene. 2013;10(11):D151-D158.
[12] Yasui S. Lessons learned: Radiological protection for
emergency workers at the TEPCO Fukushima Daiichi
APP (Part 2). Journal of Occupational and Environmental
Hygiene. 2013;10(12):D163-D171.
[13] Suto Y, Hirai M, Akiyama M, Sugiura N. Biodosimetryof restoration workers for the Tokyo Electric Power
Company (TEPCO). Health Physics. 2013;105(4):366373.

J. Natl. Inst. Public Health, 67 (1) : 2018

Lessons learned from radiation protection for emergency response and remediation/decontamination work relating to the Fukushima Daiich Nuclear Power Plant accident in 2011[14] Tominaga T, Hachiya M, Tatsuzaki H, Akashi M.
The accident at the Fukushima. Health Physics.
2014;106(6):630-637.
[15] Yasui S. Lessons learned: Medical and health caremanagement for emergency workers at the TEPCO
Fukushima Daiichi APP accident. Journal of Occupational
and Environmental Hygiene. 2014;11(5):D49-D58.
[16] Sakamoto T, Yamaguchi Y, Koido Y, Yokota Y, Aruga T.
Medical support for atomic power plant by Japanese
association for acute medicine. J Japan Med Assoc.
2012;141(1):66-70. (in Japanese)[17] Mori K, Tateishi S, Hiraoka K, Okazaki R, Suzuki
K, Kobayashi Y, et al. How occupational health cancontribute in a disaster and what we should prepare forthe future--lessons learned through support activities
of a medical school at the Fukushima Daiichi Nuclear
Power Plant in Summer 2011. Journal of Occupational
Health. 2012;55(5):6-10.
[18] Shimura T, Yamaguchi I, Terada H, Okuda K, Svendsen
ER, Kunugita N. Radiation occupational healthinterventions offered to radiation workers in responseto the complex catastrophic disaster at the Fukushima
Daiichi Nuclear Power Plant. Journal of Radiation
Research. 2015;56(3):413-421.
[19] Ojino A. Verification of Emergency Medical Care System and Response Based on Lessons Learned from
Fukushima Daiichi APP Accident. Working Paper of
JMARI. 2013;275.
[20] Tanigawa K, Hasegawa A. Medical perspective.
Radiation disaster medicine: perspective from thefukushima nuclear accident. Heidelberg: Springer; 2014.
p.29-78.
[21] Wada K, Yoshikawa T, Hayashi T, Aizawa Y. Emergency
response technical work at Fukushima Dai-ichi nuclear
power plant: occupational health challenges posed by
the nuclear disaster. Occupaional and Environmental
Medicine. 2012;69(8):599-602.
[22] Yasui S. 250 mSv: Temporar y increase in theemergency exposure dose limit in response to the
TEPCO Fukushima Daiichi NPP Accident and its
decision making process. Journal of Occupational andEnvironmental Hygiene. 2015;12(4):D35-D42.
[23] Yasui S. Fact-finding survey in response to the
manipulation of personal alarm dosimeter collection
efficiency: lessons learned about post-emergency
radiation protection from the TEPCO Fukushima
Daiichi APP accident. Journal of Occupational andEnvironmental Hygiene. 2015;12(6):D96-D102.
[24] Kurihara O, Katuta K, Takehiro N, Chie T, Takumaro

M, Sadaaki F. Direct Measurement of Employees
Involved in the Fukushima Daiichi Nuclear Power
Station Accident for Inter nal Dose Estimate:
JAEA's Experiences. The 1st NIRS Symposium on
Reconstruction of Early Internal Dose in the TEPCO
Fukushima Daiichi Nuclear Power Station Accident:
Chiba, Japan; 2012.
[25] Kurihara O, Kanai K, Nakagawa T, Takada C, Tusjimura
N, Momose T, Furuta S. Measurements of 131I in
the thyroids of employees involved in the Fukushima
Daiichi nuclear power station accident. Journal of
Nuclear Science and Technology. 2013;50(2):122-129.
[26] Yasui S. Establishment of new regulations forradiological protection for decontamination work
involving radioactive fallout emitted by the Fukushima
Daiichi APP Accident. Journal of Occupational andEnvironmental Hygiene. 2013;10(9):D119-D124.
[27] Yasui S. New regulations for radiation protection forwork involving radioactive fallout emitted by the
TEPCO Fukushima Daiichi APP Accident: Application
expansion to recovery and reconstruction work.
Journal of Occupational and Environmental Hygiene.
2014;11(8):D105-D114.
[28] Yasui S. New regulations for radiation protection forwork involving radioactive rallout emitted by the
TEPCO Fukushima Daiichi APP Accident—Disposal ofcontaminated soil and wastes. Journal of Occupational
and Environmental Hygiene. 2014;11(10):D147-D156.
[29] Yasui S. Establishment of the central radiationdose registration system for decontamination work
involving radioactive fallout emitted by the Fukushima
Daiichi APP Accident. Journal of Occupational andEnvironmental Hygiene. 2016;13(10):D166-D174.
[30] Yasui S. A recommended epidemiological study designfor examining the adverse health effects among
emergency workers who experienced the TEPCO
Fukushima Daiichi NPP Accident in 2011. Journal of
Occupational and Environmental Hygiene. 2016;13(5):132.
[31] Shigemura J, Tanigawa T, Saito I, Nomura S.
Psychological distress in workers at the Fukushima
nuclear power plants. JAMA. 2012;308(7):667-669.
[32] Shigemura J, Tanigawa T, Nishi D, Matuoka Y, Nomura
S, Yoshino A. Associations between disaster exposures,
peritraumatic distress, and posttraumatic stressresponses in Fukushima nuclear plant workers following
the 2011 nuclear accident: the Fukushima NEWS
Project study. PLos One. 2014;9(2):e87516.

J. Natl. Inst. Public Health, 67 (1) : 201891

Shojiro Yasui

福島第一原子力発電所事故に係る緊急作業及び除染作業における放射線防護に関する教訓
安井省侍郎
厚生労働省安全衛生部

抄録
本総説は，2011年に発生した東京電力福島第一原子力発電所に係る緊急作業及び除染作業における放射線防護に関する学術論文をレビューしたものである．これら論文は，2012年から2017年に出版され，本事故の経験に基づく教訓を明らかにするとともに，同様の事故に対する準備に関する指針を提供したものである．本事故については多数の学術論文が報告されているが，作業員の放射線防護に関するものは数少ない．本総説でレビューされた論文は，信頼できる一次情報に基づき，放射線防護上で発生した問題点について詳細な情報を提供しているものである．本総説は，論文を時系列に整理するのではなく，以下の4つの大きなトピック－ (a)緊急作業における放射線防護と健康管理，(b)緊急作
業後の対応，(c)除染作業に関する新たな法令の制定，(d)放射線の健康影響に関する疫学調査－に分類してレビューを行った．
キーワード：放射線防護，福島第一原子力発電所事故，緊急作業

92

J. Natl. Inst. Public Health, 67 (1) : 2018