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Decontamination

For a summary of Decontamination Methods refer to the Radiological Health Handbook.

Equipment

  1. If equipment is contaminated it should be washed with a suitable cleaning solution as determined by the contaminant and rinsed as a routine procedure. The use of acid on metal tools may unnecessarily corrode them causing greater difficulty in future decontamination procedures. If it is necessary to dismantle any equipment prior to decontamination procedures, careful survey should be made during the operation.

    Contaminated equipment shall not be released from the control of the laboratory for repair, or for any other purpose, until there is no detectable transferable contamination measurable with the survey meter. In many cases, if the items are cheap or easily replaced, it may be simpler to dispose of such equipment. Equipment that is contaminated with long-lived isotopes, and that cannot be satisfactorily decontaminated must be regarded as radioactive waste. Decay must be considered one of the best decontaminating agents for short-lived materials.
  2. Glass and porcelain articles may be cleaned with detergents, mineral acids, ammonium citrate, trisodium phosphate, cleaning solution (chromic acid) or ammonium bifluoride. Metal objects may be decontaminated with detergents, dilute mineral acids (nitric), a 10% solution of sodium citrate, or ammonium bifluoride.
  3. Where radioactive materials may be present, or where danger of personal contamination exists, workers involved in decontamination shall wear protective clothing; footwear, gloves, and self-contained breathing apparatus as the circumstances dictate.
  4. Where contamination of room air has occurred, thorough ventilation is required, with passage of air from uncontaminated areas through the contaminated areas to the out-of-doors. This should be done preferable by discharging the air into a hood that has a filtered exhaust system.

Skin

  1. Extreme personal cleanliness is the first rule in preventing contamination of the skin. Persons working with radioactive materials should wash exposed parts of the body frequently, as a matter of routine while on the job. Thorough washing and monitoring shall be mandatory whenever leaving the area.
  2. Thorough washing with soap and water is the best general method of decontamination of the hands and other parts of the body regardless of the contaminant. If the contamination is localized, it is often more practical to mask off the affected area and cleanse with swabs, before risking the danger of spreading the contaminant by general washing.
  3. If the exact nature of the contaminant is known, it may sometimes be more effective to immerse the hands in a suitable reagent immediately after contamination. Thorough washing in tepid water with mild soap and thorough rinsing in clean water should follow this. Detergents and wetting agents may also prove useful, although sometimes a specific one may be required for a particular contamination problem in order to secure maximum cleaning efficiency. A list of detergents and wetting agents that have been used successfully to remove some contaminants is presented in section E of this appendix.

    The skin may become sensitive following repeated application of detergents to the same area, therefore, care should be taken to avoid this practice. In any case, one must avoid the use of organic solvents that may increase the probability of the radioactive materials penetrating through the pores of the skin. The recommended procedures for washing hands are as follows:
    1. Wash for not less than two minutes with a mild pure soap in tepid water with a good lather, covering the entire affected area thoroughly. Give special attention to areas between the fingers and around the fingernails. The outer edges of the hands are readily contaminated and often neglected in washing. Do not use highly alkaline soaps or abrasives. Rinse thoroughly and repeat, as monitoring indicates, until the desired degree of decontamination is achieved.
    2. If the above procedure is not sufficient to remove the contamination, scrub the hands with a soft brush using a heavy lather and tepid water. This scrubbing is primarily to agitate the cleansing agent, therefore, and hence prolonged scrubbing without change of reagent is of questionable value. For this reason, at least three washes, including rinses, should be made within eight minutes of which at least six minutes should be devoted to scrubbing. Only light pressure should be applied to the brush not sufficient to bend the bristles out of shape or to scratch or erode the skin. Rinse thoroughly and monitor.
    3. Apply lanolin or hand cream to prevent chapping. Chemicals may be used for cleaning other parts of the body or the hands, if the above procedures do not successfully remove the contamination. There are two processes in general use. Procedure (1) following has been used successfully for heavy contamination; however, if this procedure is unsuccessful, it may be followed by (2).
  4. Apply a liberal portion of titanium dioxide paste to the hands. Work this paste over the affected surface and adjacent areas of the skin for at least two minutes. Use water sparingly to keep the paste moist. Rinse with warm water, and follow by thorough washing with soap, brush and water. Be sure that no paste is allowed to remain around the nails. Monitor, and repeat the entire process, if necessary. It should be noted that the condition of the titanium dioxide paste is very important. In order to be effective, the paste must be prepared by mixing precipitated titanium dioxide (a very thick slurry, never permitted to dry) with a small amount of lanolin.
  5. Mix equal volumes of a saturated solution of potassium permanganate and .2 N sulfuric acid. Pour this over the wet hands, rubbing the entire surface and using a hand brush for not more than two minutes. (Note: this application will remove a layer of skin if allowed to remain on contact with the hands too long; consequently, the times stated here should not be exceeded for any single application).
  6. Be sure that all areas are thoroughly covered. Rinse with warm water and then apply a freshly prepared 5% solution of sodium acid sulfite (NaHSO3) in the same manner as above, using a hand brush and tepid water for not more than two minutes. Wash with soap and water, and rinse thoroughly.

The above procedure may be repeated several times as long as the permanganate solution is not applied for more than two minutes during any one washing. Application to other parts of the body than the hands may be facilitated by the use of swabs steeped in the solution. Lanolin or hand cream should be applied after washing.

Wounds

Extreme precautions must be taken to avoid cuts or puncture wounds. In the event that the skin is broken in accidents while working with radioactive substances, immediate action should be taken to remove possible contamination. Wash the wound under large volumes of running water immediately (within 15 seconds) and spread the edges of the gash to permit flushing action by the water. Light tourniquet action to stop venous return (but not to restrict arterial flow) may be desirable to stimulate bleeding. Report all wounds to the responsible medical or radiological officer as soon as emergency precautions have been taken.

Clothing

Contaminated clothing shall not be released to a general service laundry. Clothing contaminated with radioactive material having short half-lives may be labeled and stored for decontamination by decay. Clothing contaminated with long-lived material shall be disposed of or sent to a laundry that is licensed by the NRC or IDNS if local decontamination is not successful.


2017-09-13T14:58:07.467-05:00 2017
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