SMBS stands for Sodium Metabisulfite (Na₂S₂O₅), a white crystalline powder used as an antioxidant, preservative, and disinfectant. In industries, it serves in water treatment, textile bleaching, and food preservation (especially dried fruits). It releases sulfur dioxide when dissolved, which inhibits microbial growth. Though effective, it must be handled carefully due to its strong odor and potential irritant effects.