News | April 24, 2001

JCO employees plead guilty to negligence in deaths at Japanese nuclear facility

The former administrator of the JCO uranium processing plant in Tokaimura, Ibaraki Prefecture, along with five other high level employees, pleaded guilty Monday in Mito District Court to charges of negligence resulting in death on the opening day of a trial looking into the Japan's worst nuclear accident. JCO pleaded guilty to violating the Nuclear Reactor Regulation Law. JCO is a subsidiary of Sumitomo Metal Mining Co.

The six employees are also charged with allowing employees to illegally use buckets to make a uranium solution. Kenzo Koshijima, 54, former head of the Tokaimura processing plant, and the other employees allegedly approved the illegal procedures at a safety committee meeting in 1995. An unauthorized, but widely distributed 1996 manual recommended the use of buckets to make the solution.

On Sept. 30, 1999, a nuclear chain reaction caused in part by the use of buckets resulted in deaths of two JCO workers and serious injuries to another. Some 600 people, including many residents of Tokaimura, were exposed to elevated levels of radiation. A total of 119 residents were exposed to more than the 1-millisievert limit on annual permissible levels of radiation.

At the time of the accident, police reported that workers at the JCO facility might not have received adequate safety training. (Koshijima and JCO are also charged with failing to instruct employees in safety.) And a report submitted to an investigative committee of the Nuclear Safety Commission by the Science and Technology Agency said that JCO management have permitted workers to use a stainless steel bucket as a short-cut for a mechanized process since 1993, even though it was a violation of written procedures.

A manager at the facility who was exposed to radiation at the scene reportedly told the police he "forgot" about the dangers posed by a self-sustaining nuclear chain reaction, and was not aware of the hazard posed by processing an excessive amount of uranium in a single batch. Two workers mixed about 16 kg (35 pounds) of uranium hexafluoride with nitric acid solution, nearly seven times the 2.4 kg (5.2 pounds) deemed safe in order to avert a nuclear chain reaction and release of radiation. They later died from their exposure to radiation. A third employee was hospitalized in critical condition.

Koshijima, along with Hiromasa Kato, 61, chief of the production department at the time, Hiroyuki Ogawa, 43, leader of the planning group when the accident occurred, and three senior workers -- Hiroshi Watanabe, 49, Kenji Takemura, 32, and Yutaka Yokokawa, 56 – responded, "That is right," when asked if they plead guilty to the charges.

JCO President Tomoyuki Inami entered a guilty plea on behalf of the company, saying, "I know it's too late for regret. I can only pray sincerely for the souls of the dead."

Koshijima, Kato, Ogawa and JCO are also charged with violating the Nuclear Reactor Regulation Law for compiling the unauthorized 1996 manual without reporting the changes in procedure to the government. Operators of nuclear facilities are required by law to obtain approval from the prime minister before changing production methods.

According to prosecutors, JCO also developed plans to hide illegal equipment and production methods from inspections by the Science and Technology Agency.

At the time the arrests of Koshijima and the others, Isao Yamazaki of the Ibaraki Prefectural Police said the six men could get up to five years in prison or $4,630 in fines if found guilty.

In September 2000, JCO announced it agreed to pay a total of $121 million in compensation to settle 6,875 cases stemming from the accident. At that time, JCO spokesman Katsunori Suzuki said the company was still trying to settle about 150 other. In addition to people exposed to radiation, the compensation covered losses suffered by businesses such as farms, fisheries and service industries.

Related articles: "Human Error, Bypassed Safety Rules, Set the Stage for Japan's Worst Nuclear Accident," "Workers, Police Blame Lack of Safety Training for Radiation Release," "Former JCO executives arrested for negligence in the 1999 nuclear accident in Japan," "Report: Japanese Authorities Were Slow to React to Nuke Accident," and "Japan implements law to improve response to nuclear accidents."

By Sandy Smith
Content Manager

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