Gradual corrosion and mechanical wear of equipment over a period of years has affected the seals and gasketing of the electric pot calcining equipment in the 224-U Building Cell E to such an extent that the desirable vacuum cannot be maintained in the pots. Air contamination has been gradually increasing, and this, together with a lowering of the mask working limits, has made it necessary to require personnel to wear assault masks continuously. Indications are that, with the increased production now required, the level of air contamination will continue to rise unless measures are taken to prevent it. The Manufacturing Department has requested that a project be established to reduce the contamination level. Several items of improvement are listed for consideration including, in general, the electric pot agitation and sealing, semi-automatic pot unloaders, cell ventilation and air locks, and the nitric acid off-gas system and stacks. Because of the urgency of improving the conditions, the project, at first, is to provide for immediate improvements for the electrical pot agitation, the pot cover leakage, and the nitric acid off-gas system and stack. Additional study will be required to determine the extent of the ventilation and semi-automatic unloading improvements required.