Sulfur dyes are commonly used in cotton and cellulose-based fiber dyeing, particularly for producing dark colors like navy and black. Their economic appeal and durability have secured their place in denim and workwear segments. However, conventional sulfur dyeing processes require sodium sulfide as a reducing agent, which introduces environmental challenges including high COD loads, sulfur odor emissions, and heavy wastewater burdens. Sustainability initiatives within this dye class center on minimizing or eliminating sodium sulfide use through the introduction of alternative reducing agents like glucose or sodium dithionite. Additionally, improvements in pre-reduced liquid sulfur dyes allow for more controlled application and reduced environmental risk. Some modern sulfur dye formulations also offer better solubility and higher exhaustion, minimizing runoff and dye loss. Tightening wastewater regulations and worker safety concerns are accelerating industry demand for sulfur dye processes that integrate closed-loop systems and sulfur recovery technologies. Certifications such as bluesign® and OEKO-TEX® require rigorous monitoring of sulfur compound residuals and compliance with restricted substance lists. B2B directories and sourcing platforms enable dyehouses and brands to access advanced sulfur dye technologies with sustainability credentials, supporting informed decisions around cost, performance, and environmental responsibility.