Decyphering TEPCO Worker Exposures

TEPCO and the WHO have issued various reports about worker exposure. Many aspects of these reports give deceptively optimistic presentations, some bury or omit inconvenient negative facts.

Some of the ways the data is compartmentalized or misrepresented is by only showing contract workers and not including TEPCO workers. During the worst of the disaster most of the workers on site doing the high exposure work were TEPCO employees. All of the highest exposures are TEPCO workers.

Contract workers that must carry a dosimeter and are considered working in radioactive conditions include the workers at J Village. These include people who do many different jobs such as  decontaminating vehicles, checking visitors for contamination, handing out protective gear to workers, food service and a variety of other support services. If all or some of these workers are included in the contract worker numbers they will make those numbers artificially low. Contract workers also includes anyone who worked at the plant even if they were only there for one day to do some sort of special work.

The actual number of workers at the plant has gone down and work efforts have been largely curtailed, fewer workers, fewer exposures. The nature of the work going on has changed also. Now that highly radioactive debris has been mostly removed and workers avoid going into the buildings if at all possible. Because of the changes to work, the numbers will obviously go down but there is still a very large amount of high exposure work that will eventually need to be done. Much of it can not be completed by robots. For now TEPCO has chosen to delay as many of those efforts as possible resulting in future problems of larger proportion.

There is also a string of issues where workers have reported exposure faking. Workers cited that their dosimeters would error out in areas of high radiation. This results in no reading for that time or a reading only up to the maximum capable by the dosimeter. Workers have reported many times where workers set their dosimeter down or handed it to other workers while they ran in to do a task in a high radiation area. There was also a scandal where contract workers were instructed to cover their dosimeters with lead shields to fake their doses. Workers have also reported that the scanners used to check their exposure as they leave the plant were set to scan too fast resulting in artificially lower exposure readings. Workers were motivated to fake their doses in order to remain employable. Most workers simply lost their jobs with no compensation or support when they hit maximum exposure. This caused the short sighted motivation to cooperate with dose faking.  This will have larger implications as any sort of post-work medical monitoring is based on the exposure doses recorded by TEPCO.

All of these issue create distorted or unreliable exposure numbers.

Reports in 2011 establish the worker doses for the first 3 months of the disaster.

  • 6 workers were over 250 mSv, all of them TEPCO employees
  • 14 workers were between 150-200 mSv, 12 of these were TEPCO employees
  • 81 workers had 100-150 mSv of exposure, 15 were contract workers
  • 306 workers had 50-100 mSv of exposure, 116 were contract workers
  • 953 workers had 20-50 mSv of exposure, 420 were contract workers
  • 1449 workers had 10-20 mSv of exposure, 915 were contract workers
  • 7088 workers had 10 mSv or less of exposure, 5865 were contract workers

The actual numbers over 250 mSv have been hard to find. We know 6 workers are over that limit but their actual doses are not generally disclosed. Asahi Shimbun reports one worker as having 678.8 millisieverts of exposure. METI reported a worker as having 672.27 millisieverts and being the highest dose. METI does cite that the 6 workers with high exposures were those involved with manning the control rooms and other direct countermeasures like trying to repair the electrical systems and reading instruments. What has not been mentioned is the exposure levels for the workers who went on suicide missions into the reactors to manually operate vents. For the venting of unit 1 alone, 6 workers formed a team to attempt to release the vent valves while the reactor was already melting down. This was also attempted at units 2 and 3. At least one of the workers attempting to vent the reactors suffered from extreme exposure and was transported offsite for medical assistance according to IBtimes. They seem to be citing a press release from the Prime Minister’s office.

A new report by TEPCO has few useful facts in it, some that we found buried in the technicolor graphs were:

  • 50 mSv is the current annual exposure maximum
  • In 2012 they attempted to keep contractor monthly exposures to below 20 mSv, some exceeded this
  • TEPCO only used April-August to look at certain exposures, this throws out most of the higher doses in 2012 by eliminating those months
  • Higher monthly doses occured between January to April and mid August to mid September, with no data after September these were over 20 mSv/month
  • The months of April to August appear to coincide with less invasive work being conducted at Daiichi
  • These were also the hottest months requiring a shorter daily work schedule to compensate for the heat
  • TEPCO and contractors are rotating workers between high and lower exposure jobs meaning exposure is just spread among more people
  • TEPCO uses the term “dismissed” but makes no clarification between workers told not to return and those who left on their own for various reasons or had their work role ended.
The convenient shuffling of numbers makes TEPCO’s report look good on the surface. It is largely a game of deception. The report is titled “Overview Of The Radiation Exposure Doses Of The Workers At Fukushima Daiichi Power Station. It makes no clear statement that this is only contract workers, you must dig deeper to discover that. The entire focus of their proof of improvement uses a short 5 month span when limited work was conducted and ignores exposures of TEPCO workers during that time. The “new and improved” TEPCO that was supposed to be more honest and accountable is still up to the same tricks as the old dysfunctional TEPCO. 




This article would not be possible without the extensive efforts of the SimplyInfo research team
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