Objective Review

Abstract

Leather industry uses a great number of processing chemicals to make leather from animal hides. The toxicity, health and environmental impacts of many of these chemicals have been established leading to significant regulatory certifications and programs helping in trade and policy making. The focus of this review are the hazardous chemicals and auxiliaries relevant to leather industry, their categories, possible origins, analysis and toxicity with respect to humans and the environment and the regulatory mechanisms suggested for them through manufacturing restricted substance list (MRSL) 2.0.** Informative guidelines are provided about the most probable leather processing stage for the origin of these chemicals. Some alternative technologies, chemicals and ideas gaining popularity are also suggested as probable remedies. Recommended test methods are stated for the adequate monitoring of the hazardous chemicals. The nature and severity of chemical toxicity and corresponding limits set for their allowed use in formulations are graphically expressed for clarity and ease of understanding. The maximum number of compounds / isomers belong to classes comprising chlorinated paraffins, perfluorooctanoic acids (PFOA), perfluorooctanesulfonates (PFOS) and banned aromatic amines. Similarly, most of the restricted chemicals are used during the finishing stage and may be considered for eco-friendly alternatives. Likewise, the analytical equipment covering most testing requirements is GC-MS among other hyphenated techniques. Additionally, most critical chemicals from toxicity point of view are arsenic, cadmium and chromium (VI), whereas navy blue colorants and chlorinated aromatic compounds may be considered as less toxic among the restricted chemicals under the current scope. Surprisingly, the latest UV absorbents and polymeric fatliquors are comparatively non-toxic. Similarly, the most relaxed formulation limits are given for UV absorbers and 2-methoxypropylacetate whereas strict limits have been set for PFOA, PFOS, mercury, triclosan permethrin, sensitizing dyes etc. in MRSL 2.0.