Used primarily as a stabilizer in polyvinyl chloride (PVC) plastics, this compound prevents degradation during processing and extends the lifespan of PVC products. It is especially effective in rigid PVC applications such as pipes, sheets, and profiles, where long-term thermal and UV stability are required. Also serves as a catalyst in the production of polyurethanes and certain silicone curing systems. Due to its biocidal properties, it has been used in antifouling coatings to prevent marine organism growth on ship hulls, though such uses are now restricted in many regions due to environmental concerns. Its application is carefully regulated because of toxicity to aquatic life and potential endocrine-disrupting effects.