Re: Radiation hazard preventive measures for decontamination workers based on “Basic Policy for Emergency Response on Decontamination Work” and “Guidelines for Municipal Decontamination Work”

With regard to contamination of radioactive materials discharged by the accident at the TEPCO Fukushima Daiichi Nuclear Power Plant associated with the Great East Japan Earthquake, on 26 August 2011 the Nuclear Emergency Response Headquarters released the “Basic Policy for Emergency Response on Decontamination Work” and “Guidelines for Municipal Decontamination Work” (hereinafter referred to as the “Guidelines”) (See Annex 1).

The Guidelines define the items to be executed by the municipal governments to decontaminate the areas where additional radiation exposure dose is in the range of approximately 1 mSv/y to 20mSv/y. In the case that construction machines will be required to carry out highly risky operations at areas where the radiation dose rate is high, the decontamination works shall be commissioned to specialized decontamination operators.

Based on the policy and the guidelines, it has been concluded the employers shall take the following actions regarding workers engaged in the decontamination works. The District Labour Bureaus are expected to ensure that nothing goes amiss in supervision of the relevant employers.

It should be noted that a notification per Annex 2 was also sent to the Governors of Iwate, Miyagi, Fukushima, Ibaraki, Tochigi, Gunma, Saitama, Chiba, and Kanagawa Prefectures.

1. The employers, when assigning the workers to the decontamination works, shall follow the items listed in 4(2) of the “How professional service providers should manage radiation doses”.
   1. The employers, when assigning the workers to the decontamination works, shall take the following actions besides those mentioned above. The external exposure dose shall be measured for each worker using personal dosimeters and their data shall be recorded every day. These records shall be kept for 30 years. Workers shall be notified of the daily exposure dose every day, and of cumulative exposure dose once a month; these notifications shall be in writing.
   2. Based on the results in 1) above, the exposure dose shall be controlled and kept under 20 mSv per year for male workers and females workers who are not pregnant or are not expected to be pregnant, or under 5 mSv per three months for female workers who are or are expected to be pregnant.
   3. The employers shall make sure that the workers wear respirator equipment with a performance level of RL3 or RS3 (for example, a replaceable dust mask with a particle collection efficiency of 99.9% and RL3 shall be used when radioactive gases are present in the air)¹. The workers shall wear effective respiratory protective equipment depending on the level of operation. Attention shall be paid to ensuring that the respiratory protective equipment is closely fitted to the face surface.
   4. Workers on duty shall not smoke, eat or drink at the work places.
   5. Depending on the degree of possible contamination to workers during the decontamination works, they shall be provided with appropriate protective clothes, gloves, and shoes for contamination control, and they shall wear these items while on duty.
   6. Before starting the works, the workers shall be given: (a) knowledge about radioactive materials and objects contaminated with radioactive materials; (b) knowledge about the decontamination works and the structure and use of the equipment and tools for decontamination; (c) effects of ionizing radiation on the living body;(d) knowledge about the relevant laws and regulations; and (e) knowledge about the decontamination method and handling and use of the equipment and tools for decontamination.
   7. Workers shall be provided with periodical health examinations which are equivalent to or more thorough than the ionizing radiation special medical examinations², at least once every 6 months for the full time workers are engaged in the decontamination works.

• Basic Policy for Emergency Response on Decontamination Work PDF*
• <Guidelines for Municipal Decontamination Work PDF*