This report describes research directed toward the preparation of chemical oxygen (o2) sources that exhibited improved o2 storage and reaction characteristics when compared with potassium superoxide (ko2). The initial focus of the research was the preparation of calcium superoxide (ca(o2)2) by the disproportionation of calcium peroxide diperoxyhydrate. The ca(o2)2 was characterized by chemical, thermal, and x-ray analyses. Several methods for scaling up the ca(o2)2 synthesis process were studied. Next, the reactivity of ca(o2)2 toward humidified carbon dioxide (co2) was evaluated and was compared with that of ko2 under flow-test conditions approximating those existing in portable breathing apparatus. The reactivities of mixtures of ko2 and ca(o2)2 or lithium peroxide toward humidified co2 were also studied. Finally, an analysis of two commercial, ko2-based, self-contained self-rescuers was conducted to determine the potential weight and volume savings that would be possible if ca(o2)2 or a mixture of ko2 and ca(o2)2 were used as a replacement for ko2.