How has arsenious oxide been used in glassmaking?

In the context of glassmaking, arsenious oxide—also known as white arsenic—has historically been utilized as a decolorizer. Additionally, it was customary in the past to add approximately 0.25 percent arsenic oxide, often in combination with sodium nitrate, to assist in the process of glass fining, which involves the removal of bubbles from the molten glass.12

It is important to note that these chemicals are no longer recommended for use in modern glass manufacturing due to the significant health and environmental hazards they pose. Industry standards have shifted toward the use of less noxious alternatives, such as sodium chloride or sodium sulfate, to achieve similar results while prioritizing safety and environmental protection.2