A method for sequestrating arsenic oxides, comprising forming an insoluble and stable glass incorporating a fully oxidized form of arsenic generated by oxidation of an initial lower oxide of arsenic and stabilization by calcium salt formation. The glass composition for sequestration of arsenic comprises from 50 to 75% silica; from 0.5 to 3% Al2O3; from 1 to 15% MnO; from 5 to 15% CaO; from 1 to 20% As2O5 and from 8 to 14% Na2O, less than four percent of iron oxides, magnesium oxide and other oxides.