The denim industry’s cheapest bleaching shortcut is now formally flagged as a “substance of concern” in a tool meant to standardise risk language across supply chains.
Denim’s distressed look has always been engineered. What is changing is the tolerance for the chemistry behind it. ZDHC has published a new Chemical Watchlist v1.0—and potassium permanganate (KMnO₄), a workhorse oxidizer for localised denim bleaching, is on it.
ZDHC’s Chemical Watchlist v1.0 is a provisional, expert-reviewed reference containing 1,624 substances relevant to textiles, leather, apparel and footwear. It is explicitly broader than the MRSL, covering substances that may also show up in emissions and that can affect human health, environmental outcomes or circularity.
Watchlists change behaviour even when they aren’t banned. They have become a shared vocabulary for brands, chemical formulators and mills—reducing “interpretation risk” in audits, reporting and buyer requirements. KMnO₄’s inclusion is awkward for denim because the business case is strong: it is cheap, effective and easy to apply, which is precisely why it persists despite years of “cleaner finishing” rhetoric.
Expect procurement pressure to rise in three places: (1) input substitution (laser, ozone, enzyme systems, safer chemistries), (2) process control (robotised application, extraction/water curtains, PPE), and (3) claims discipline—because “safer chemistry” will increasingly need evidence, not slogans. ZDHC already urges suppliers to evaluate alternatives to manual permanganate spraying and to use engineering controls where it remains in use.
