Dom Smith | EcoFlight This aerial photo shot in April shows the White Mesa Uranium Mills evaporation ponds, which environmentalists and Ute Mountain Ute tribal officials fear are emitting radon gas far in excess of federal standards. The 55-acre pond on the left is Cell 1, the one with the highest concentrations of radium waste. The mill is 6 miles south of Blanding on U.S. Highway 191.