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Restrictions on Organotins Tightened to Prevent Abuse

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The EPA preannounced the amendment of the Regulated Toxic Chemical Substances and Matters Concerning Their Handling and Management () , which will strengthen the management of organotin compounds. In addition to continuing the original controls on activities such as manufacturing, the amendment will prohibit the use of organotin compounds in the manufacture of anti-fouling paints, anti-fouling systems and biocides. The amendment will also give operators a buffer implementation period of one to two years to adjust to the new toxicity classifications of organotin compounds.

The International Convention on the Control of Harmful Anti-fouling Systems on Ships has imposed restrictions on the use of organotin compounds. These compounds were often used in coatings for ships, box nets and other tools to prevent conch, barnacles and other marine organisms from adhering. They were also widely used as biocides such as insecticides and molluscicides. However, these uses also caused organotin compounds to be distributed in water bodies where they would accumulate in shellfish, fish and aquatic organisms. Due to their endocrine disrupting properties, these compounds may cause mutations in aquatic organisms and subsequently harm human health.       

Currently, 35 organotin compounds are announced and listed as toxic chemical substances. After referring to international databases and related scientific research, in this amendment the EPA has updated information on these substances by adding the Chemical Abstracts Service Number (CAS No.) of triphenyl-α-naphthyltin, tripropyltin fluoride, tritolyltin bromide and tritriphenylstannyl-methane, and adjusted the toxicity classifications of ten organotin compounds, namely tributyltin oxide bis(tributyltin)oxide, triphenyltin hydroxide, tributyltin acetate, tributyltin bromide, tributyltin chloride, tributyltin fluoride, tributyltin hydride, triphenyltin bromide, triphenyltin acetate, and triphenyltin chloride. 

In addition, the EPA also referenced international management regulations such as those of the United Nations and European Union and revised the prohibited operations and permitted uses of organotin compounds, banning their use in the manufacture of and in the application of anti-fouling coatings or anti-fouling systems. So as to strengthen the source management and ensure their safe use, organotin compounds can only be used in the production of medicines and as polyurethane resins and plastic stabilizers, with the exception of uses for research, experiment and education. 

Excerpt from Major Environmental Policies, October 2022
Ministry of Environment