Is soda burning toxic?

Toxic. According to the inquiry data, soda ash is added in soda ash firing, so that sodium carbonate in soda ash reacts with silicon dioxide at high temperature in the kiln to generate soda ash glaze. The decomposed sodium combines with silicon dioxide to form a glaze layer, and the decomposed chlorine combines with hydrogen in the kiln to form hydrochloric acid, which is toxic and harmful to air and kiln workers.