pr_140604 | TEPCO Fukushima Daiichi NPP | Radiation Protection of Workers

Press release

4 June, 2014

Office for Radiation Protection of Workers,
Occupational Safety and Health Department,
Labour Standards Bureau

Policies for Epidemiological Studies Targeting Emergency Workers at the TEPCO Fukushima Daiichi Nuclear Power Plant Have Been Compiled

The Ministry of Health, Labour and Welfare (MHLW) has compiled a report of the Expert Meeting on Epidemiological Studies Targeting Emergency Workers at the TEPCO Fukushima Daiichi Nuclear Power Plant (chaired by Mr. Toshiteru Okubo, Chairman of the Radiation Effects Research Foundation).

For emergency work at the TEPCO Fukushima Daiichi NPP, the emergency exposure dose limit was raised from 100 mSv to 250 mSv during the period from 14 March to 16 December 2011. During this period, approximately 20,000 workers engaged in emergency work, out of which 174 workers were exposed to radiation exceeding 100 mSv, which is the dose limit for five years for workers engaging in normal work. It is a concern that these emergency workers may suffer health impairment due to their radiation exposure; the MHLW has built a database for long-term health care, which accumulates exposure doses and other data, and has been managing such workers’ health care on a long-term basis, based on the MHLW ’s Ministerial guidelines.*

Since February 2014, this Meeting has discussed how to make plans for epidemiological studies targeting emergency workers concerning the effects of radiation on human health. As a result, the following notifications have been presented for establishing plans of epidemiological studies.

Major Suggestions in the Report

Study targets
All of the 20,000 emergency workers should be included and the study period should last throughout the respective workers’ lifetimes.
Exposure factors to be examined
1. The fundamental purpose is to examine the effects of cumulative doses on human health. When further examining health effects of short-term exposure or exposure dose by organ, small groups should be set up from among all of the study targets.
2. Psychological effects should also be examined.
Study methods
1. Prospective cohort study (a method to follow a group of study targets throughout their lifetimes)
2. Study targets are encouraged to visit a medical institution for a thorough examination or to get health guidance as necessary.
3. All analysis results, including those showing no statistically significant difference, are to be publicized.
Follow up and maintenance of the study target group
There should be follow up and maintenance of the study target group and this should be done by utilizing the survey of the current health state of the targets being conducted by the MHLW in the course of managing the database for long-term health care.

*Guidelines on Maintaining and Improving the Health of Emergency Workers at the TEPCO Fukushima Daiichi Nuclear Power Plant (Guidelines Public Notice No. 5, dated 11 October 2011)

In response to this report, the MHLW started to conduct baseline studies for 10% (about 2,000 emergency workers) of the target group from this fiscal year in preparation for full studies from FY2015 onward.

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