Reducing the mid-infrared attenuation loss due to absorption of hydroxyl (OH) groups and scattering of metallic Pb species for lead-germanate glass is essential to pave the way for their applications as low-loss mid-infrared fiber optics. In the first part of this study, we report the understanding of the factors that determine dehydration efficiency and metallic Pb formation during the lead-germanate glassmelting process. Combining a dry O-2-rich atmosphere containing ultra-dry N(2)together with the use of chloride dehydration agent and nitrate oxidation agent compound was found to enable efficient dehydration effect and absence of metallic Pb scattering sources in the dehydrated glasses. This glassmelting procedure overcomes previous limitations on the preparation of similar kinds of heavy-metal oxide glasses, where only pure O(2)atmosphere was used and/or use of fluoride dehydration agent deteriorated the glass thermal stability. This work provides guidance for developing other low-loss mid-infrared glasses/fibers containing multivalent heavy-metal ions such as Pb, Bi, Te, Sb, etc