would be desirable to maintain the existing wells around the crater since rates and fluxes of material from the crater to the well sites are established. Quantities of dye, such as Rhodamine B, could be added to the soil fill during clean up operations. Detection of any quantity of this dye in the lagoon water or groundwater would provide an early warning of possible structurai defects and identify routes of contaminated water flow. In addition, continued radiological surrveillance should be maintained on marine food products in the local marine environment. Cactus Crater is a valuable environmental aquarium. It would be difficult to duplicate such a structure anywhere else in the world. Destroying the crater will result in the loss of a very unique natural laboratory both from point of view of radionuclide studies and mariculture experiments. Efforts should be made to protect this now natural structure during clean up. The radionuclides in the crater water and sediment make various marine experiments feasible which would be difficult or impossible to conduct elsewhere. Types of experiments could include basic chemical studies of plutonium in salt water systems and defining recycling processes of plutonium by biotic and chemical means in terrestrial and aquatic environments. The natural outdoor laboratory could be operated by the existing MPML at Enewetak and be made available to investigators for radiological and marine studies.