Whitepaper Chrome VI

Chrome VI and leather

The presence in leather of what is generally called ’Chrome Six’ is an undesired effect related to the use of chrome tanning agents. Since tanning with chrome salts constitutes roughly 80% of the processing technology worldwide, the debate about the risk for its presence is too important to be based on hearsay instead of facts.

Download the whitepaper and learn about:

  • The background on Chromium VI
  • Its relation to wetblue
  • The risks
  • Ways to avoid it
  • Available test methods

Download the whitepaper on Chrome VI

What is Chromium VI?

What we call ’Chrome Six’ is chemically known as Cr(VI) or Cr6+. Cr(VI) is one of the possible forms of the element chromium. These different forms are expressed as oxidation states. For chromium, from now onwards to be called ‘chrome’, they are: +6 +5 +4 +3 +2 +1 0 and -1 -2. For tanners the trivalent and hexavalent states are of importance.

During tanning trivalent Cr3+ is used. This oxidation state is causing its green colour when the element reacts with oxygen to Cr2O3. It enables the production of green pigments and gives emeralds their incomparable colour. Cr3+ is also a trace element essential for our bodies to function.

The hexavalent Cr6+ is used as an intermediate in metallurgy and in chemical synthesis. This intermediate step strips chrome of its impurities and is necessary before chrome can be used as ingredient for the various purposes. Cr6+ has a known toxicity and is classified as CMR (Cancerogenic – Mutagenic – Reprotoxic).

Chemicals & substances


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