A senior official of a construction company has admitted that he and four workers used lead plates to shield their dosimeters to lower radiation readings inside the embattled Fukushima No. 1 nuclear power plant in December.
The 54-year-old official with Build-Up, a subcontractor in Fukushima Prefecture, told The Asahi Shimbun on July 22 that they used the shields for 30-40 minutes. He also admitted that he had concocted a lie for the workers beforehand if they were asked why their protective suits were taped where their pocket-sized dosimeters are carried.
While his account gave some details, the whole extent of the company’s actions have yet to be revealed, including the motive and whether it was involved in similar deceptions in the past.
In addition, some of the official's accounts contradicted what other workers told The Asahi Shimbun before it carried the report on the subterfuge on July 21.
The lead plates were used to keep radiation dose readings low enough so that the workers could continue to work as long as possible before exceeding the annual limit of 50 millisieverts of exposure set by the government. Readings of gamma radiation from cesium-137 are believed to be cut in half if a dosimeter is covered with a 7-millimeter-thick lead plate and to one-10th with a 22-mm-thick lead plate.
According to the official, he and some workers had made 12 lead shields on Nov. 30 ahead of their assignment to wind insulation around hoses of a treatment system for radioactive water. Tokyo Electric Power Co. the plant operator, had outsourced the work to Tokyo Energy and Systems Inc., a TEPCO group company, which then subcontracted part of the work to Build-Up.
Before going in, the Build-Up official told a team of workers at a lodging in Iwaki in the prefecture that they should cover their personal dosimeters with the lead plates due to high radiation levels at the work site.
On Dec. 1, he sliced open the chest portion of his protective suit with a cutter blade inside a vehicle in a parking lot near the work site. The official then put the lead shield over his dosimeter and closed the opening with transparent tape.
He also made sure that four workers working at the same site with him did the same. He instructed them if they were asked about the tape in a check when they left the plant to say that they were repairing a tear in their suits. But a supervisor with Tokyo Energy & Systems failed to notice the tape as they put on waterproof clothes over their protective suits.
The official said that a dosimeter alarm actually went off during the work, as it did when he visited the site beforehand to inspect it, as the shields were loose.
The lead plates were not used the following day and after because he concluded that they were not effective in bringing down dosimeter readings.
He said he had disposed of the lead plates in the metal waste disposal site on the grounds of the plant.
The Health, Labor and Welfare Ministry began searching the Fukushima No. 1 nuclear plant on July 21 for possible violations of the Industrial Safety and Health Law. They are examining documents related to radiation exposure records for Build-Up workers, as well as searching for the lead plates.
A company is required to take safeguards to protect its workers at a site that is potentially dangerous. A violator faces a jail term of up to six months or a 500,000 yen ($6,330) fine.
Even if workers did not actually use the shields, a supervisor pressuring them to perform an illegal act could be charged with coercion under the Criminal Law.
The Build-Up official apologized for having his workers participate in the deception and took full responsibility.
He denied, however, that he was involved in similar attempts to falsify in the past.
But the question remains whether the incident was the first time the official tried to manipulate radiation exposure readings in a nuclear plant.
In a taped conversation on Dec. 2 with workers who refused to use the shields, he told them that he managed to work despite high radiation levels many times, in one way or another.
The official also referred to a need to work under such circumstances in the future.
Although the official said he came up with the idea for the shields on his own in an instant, it is doubtful that a person, who claims to have never done such a thing in the past, can come up with such a scheme without assistance.
The workers could have been exposed to more hazards through the use of the shields to prevent their dosimeter alarms from going off, without proper steps in place to protect them from the high radiation levels.
The official, who has worked in a number of nuclear power plants in the nation for more than 20 years, must have been aware of the risks.
But he said that he used the shields to help ease workers’ anxieties because some had never worked inside a nuclear power plant before.
The taped conversation played to The Asahi Shimbun showed that the official wanted to use the shields so that his workers could continue to work longer before maximum exposure readings were reached.
(This story was written by Toshio Tada, Tamiyuki Kihara and Jun Sato.)
The excerpts of the official’s interview with The Asahi Shimbun follow:
* * *
Question: What were the circumstances of Dec. 1 when you used lead plates to shield the dosimeters?
Answer: We actually used the lead plates for 30-40 minutes. We had covered the dosimeters with the lead plates before a supervisor from Tokyo Energy & Systems arrived on the scene. We didn’t want him to see the lead plates. I had instructed the workers beforehand to tell officials that we taped the protective suits with transparent tape because they were torn if we were asked (about the tape).
Q: Of the four people who actually used them, apart from you, is there anybody who refused to use the lead plates?
A: I explained about the use of the lead plates at an inn in Iwaki, Fukushima Prefecture, on the night of Nov. 30. Nobody took issue with it. If there was somebody who was opposed, I was going to remove that person from the work assignment. I did not intend to force them.
When I surveyed the work site on Nov. 28, my dosimeter sounded an alarm in extremely short intervals. Due to high radiation levels, I thought about using “lead aprons” or “lead vests,” but they were not available. Even if we could not shield our entire bodies (from radiation), I figured that it might make a difference if our dosimeters were covered by lead plates. I came up with the idea on my own.
Q: A lead plate does not protect a person from exposure to radiation.
A: For some of our team members, it was their first time to work at a nuclear power plant. So, I thought the use of the lead plates might help ease their anxieties. But if I look at it objectively, I know I was wrong. I would like to apologize from the bottom of my heart for causing all the trouble.
Q: The recording of the conversation (that was obtained by The Asahi Shimbun) revealed that you told the workers, “You can’t keep working when you reach the maximum dosage level.”
A: Some people were new to working at a nuclear power plant, so I tried to explain in a way that would be easier for them to grasp. The following day, I sent back to the lodging three workers who declined to cover their dosimeters. I thought it would be troublesome that despite working in the same place, some would use the lead plates while others would not.
Q: You indicated to your workers that you have used the lead plates before.
A: I think I suggested something like that as an embellishment, but I have never actually done that.
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