Chrome VI is a kind of poison harmful to human and environment. It is easily absorbed by human through assimilation, respiratory tract, skin and mucosa. It will lead to raucity, nasal mucosa atrophy, especially perforation of nasal septum and bronchiectasis by air, disgorge and stomachache by assimilation, peltry and eczema by skin. The most serious damage is carcinogenesis .

Cr plays an important role in tanning leather, and makes it flexible. In electricity, metal processing, electroplating industries, the solvent contains Cr(Ⅵ). The residual Cr(Ⅵ) in leather will be absorbed by skin and respiratory tract, and damage to stomach, liver, kidney, and eyes, retinal hemorrhage and optic atrophy appearing.

Chrome tanned leather is an extremely useful and valuable commodity for most industries because of its flexibility.  The naturally occurring chrome III, which is used as the tanning agent, is perfectly safe if the leather is produced under the correct conditions and must not be confused with chrome VI.  There are many advantages of using chrome tanned leather and this is why it is preferred for most leather products.

In leather production there are three ways in which chrome III could oxidise into chrome VI:

During the tanning process –If the temperature or pH is too high then chrome III has the propensity to oxidise to chrome VI.

Chemicals used –If chrome powder is sourced from a non-reputable supply then there is a possibility that it may contain chrome VI.

Finished leather –After the leather has been made, there is a small chance of chrome III oxidising into chrome VI at high temperatures.  This is why chrome tanned leather should never be incinerated.

The test method to detect chrome VI has recently been revised and published as EN ISO 17075:2007.  This method has a detection limit of 3ppm and for a leather to pass; chrome VI must be none detected.