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Chromium (VI) in leather clothing and shoes problematic for allergy sufferers!

10/2007, 02.07.2007

BfR recommends strictly limiting levels in leather goods

Studies by the regulatory authorities of the federal states reveal that many leather goods like gloves, shoes or watch straps which come into direct contact with the skin contain high levels of chromium (VI). Hexavalent chromium is a strong allergen and it can lead to allergic skin reactions like contact eczema in sensitised individuals. The substance was detected in more than half the leather goods examined. In one sixth of the leather goods tested the levels were higher than 10 milligram per kilogram leather. The only way of preventing allergic reactions is for allergy sufferers to avoid any contact with leather goods that contain chromium (VI). "More than half a million people in Germany react sensitively to this substance”, says Professor Dr. Dr. Andreas Hensel, President of the Federal Institute for Risk Assessment. “Leather consumer goods, in particular leather clothing should not, therefore, in principle contain any chromium (VI) at all”.  Hence BfR proposes restricting the use of chromium salts in leather production as far as possible or technically reducing their concentrations during processing to such an extent that chromium (VI) can no longer be detected in the end product.

It has been common knowledge for some time now that chromium (VI) can trigger allergies. In Germany experts believe that more than half a million people are affected. The typical clinical picture is allergic contact eczema on the areas of the skin which come into contact with chromium (VI). Clothing which has direct skin contact should not, therefore, contain any chromium (VI). At the present time the chromium content of leather goods has not been regulated by law apart from industrial safety provisions. In 2006 a DIN standard stipulated that the chromium (VI) levels in work gloves must be below the detection limit. It is currently around three milligrams releasable chromium (VI) per kilogram leather.

The regulatory authorities of the federal states examined the chromium (VI) levels in leather goods between 2000 and 2006. Chromium (VI) was detected in more than half of the 850 samples; in one sixth the levels were even higher than 10 mg per kilogram leather. The leather goods contaminated with chromium (VI) also included items of clothing worn next to the skin, for instance gloves or shoes but also leather watch straps. BfR is of the opinion that the chromium (VI) levels identified in the leather could trigger allergic skin reactions in sensitive individuals.

Special tanning processes are used to introduce the chromium (VI) into the leather hides. Normally, chromium (III) sulphate is used as the tanning agent in this process. Chromium (VI) either appears as an impurity in the tanning substance or it is formed through oxidation from chromium (III) in the ensuing processing stages. There are methods available which can considerably reduce the chromium levels in the leather or even completely remove the chromium (VI). Chromium-free tanning methods are another option. The study by the regulatory authorities of the federal states showed that there were also products in each of the groups examined that did not contain any chromium.

We know from clinical studies that even the lowest levels of chromium (VI) in leather are sufficient to trigger an allergic reaction in hypersensitive individuals. At a level of 5 mg per kg leather half of the sensitised individuals already manifested allergic skin reactions like for instance contact eczema. The only effective protection for them against skin disorders is to avoid any contact with products containing chromium (VI).

As no indication is given of the method used to tan the leather product, the consumer cannot tell whether the product contains chromium (VI) or not. BfR, therefore, believes that leather goods that come into contact with skin should not, if possible, contain any chromium (VI). At the very least, the levels should be reduced as far as possible. At the present time, the analytical detection limit is approximately 3 mg per kg leather. The studies by the regulatory authorities and the standard for work gloves prove that this limit can be complied with by using the corresponding technologies. On the other hand, mandatory declaration could help allergy sufferers to consciously avoid purchasing products containing chromium (VI).

The Federal Government’s Action Programme to Combat Allergies would be a good occasion to develop the existing alternatives to the use of chromium salts in leather production.

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