Sodium sulfite is primarily used in the pulp and paper industry. It is used in water treatment as an oxygen scavenger agent, in the photographic industry to protect developer solutions from oxidation and (as hypo clear solution) to wash fixer () from film and photo-paper emulsions, in the textile industry as a bleaching, desulfurizing and dechlorinating agent and in the leather trade for the sulfitization of tanning extracts. It is used in the purification of for military use. It is used in chemical manufacturing as a sulfonation and sulfomethylation agent. It is used in the production of. It is used in other applications, including of ores, , food preservatives, making dyes.