Potassium permanganate, a chemical oxidizer that is used for localized bleaching by the denim industry, is one of 1,624 chemicals on the ZDHC Chemical Watchlist Version 1.0.
The new watchlist is an expert-driven, peer-reviewed reference tool designed to help the textile, leather, apparel and footwear industries make informed chemical decisions. It serves as a reference to for brands and suppliers to identify substances which may pose a risk to human health, the environment or circularity outcomes.
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It also includes substances that may appear in emissions and is not limited to the scope of the ZDHC Manufacturing Restricted Substances List (MRSL).
With the watchlist, ZDHC aims to create a common language for identifying substances of concern. By offering a shared language, ZDHC said the list enables “organizations to align internal teams and external partners, reduce interpretation risk and support more consistent sustainability and reporting practices.”
Despite the denim industry’s efforts to adopt safer and cleaner chemical practices, potassium permanganate remains a thorn in the industry’s side. A significant factor behind its popularity is its cost-effectiveness. The oxidizer is one of the least expensive and easiest products to apply.
Potassium permanganate is in the Candidate List of the ZDHC MRSL V3.1, meaning that it is a potential candidate for phase-out and addition to the main list in the next update of the ZDHC MRSL.
A 2024 report by Clean Clothes Campaign Turkey said the odorless, sand-like solid chemical is the cause for facial skin problems, blurred vision, respiratory issues, chest tightness, and lung inflammation. The report claimed that long-term exposure to the substance can damage the liver and kidneys.
In an interview with SJ Denim last year, ZDHC said its position is that potassium permanganate must never be used without appropriate engineering controls and workers must always use appropriate personal protective equipment.
“Suppliers are strongly encouraged to evaluate alternatives to manual spraying of potassium permanganate such as lasers, robotized spraying or safer chemical alternatives,” ZDHC stated.
