such measurements will probably not provide any significant information particularly since the principal hazards on Enewetak were from inhalation or ingestion of alpha emitters. “Types of Masks - The four principal types of protective masks used on Enewetak were the full face piece positive pressure mask, the half face piece positive pressure mask, the full face piece negative pressure mask, and the paper surgical mask. The positive pressure masks contain a cannister and portable electro-mechanical air supply. These masks provide the highest degree of protection from inhalation or ingestion of contaminated airborne particles. pressure mask. The next most effective is the negative This mask is operated through a little cannister on the negative pressure developed by the individual's lungs. While this is an effective mask it was not used in high hazard operations. mask is the only paper mask that was used. The surgical This was used to provide a mechanical filtering capability in low risk areas but more importantly, as a means to encourage discipline in controlled areas which required personnel to fefrain from smoking, eating, drinking, and putting fingers in the nose or mouth thereby reducing the potential for ingestion of contaminated particles. Post Cleanup Discovery of Radioactive Debris - Since completing the eatior cap, theTask Group has randomly discovered some radioactive debris-as eae result of shifting beach sands and other natural changes. To accommedate disposal of this material two (2) box type additions to the crater, each 20 feet by 20 feet, have been built to the same standards as the containment structure. A third 8 feet by 8 feet addition is now under construction and will be used to contain any radioactive scrap discovered