The distribution of trace radionuclides in secondary metal smelters provides an analog for spent fuel released from packages during a volcanic eruption. The fraction of the inventory of a radionuclide that would be released into the air in a volcanic eruption is called the dust partitioning factor. In consequence analyses of a volcanic eruption at Yucca Mountain, a value of one has been used for this parameter for all elements. This value is too high for the refractory elements. Reducing the dust partitioning factor for refractory elements to a value equal to the fraction of the magma that becomes ash would still yield conservative estimates of how much radioactivity would be released in an eruption.