EU’s proposal to restrict Cr (VI) in leather in final stages

Chromium is a heavy metal element that can be present in different forms such as chromium (III) and chromium (VI). Chromium (VI) is a known carcinogen and can also cause skin irritation, corrosion, ulcers, sensitization, and allergic contact dermatitis. It is hazardous both in its airborne form and when a product is in close contact with the skin. As a potent sensitizer, chromium (VI) can elicit allergic reactions at very low concentrations in already sensitised persons. Because of these human health risks, hexavalent chromium is already restricted in some products such as cement to prevent harm to workers or electronic equipment to prevent environmental pollution by waste disposal (see the EVISA Information on Legislation). 

The use of chromium salts in leather tanning dates back to the middle of the 19th century and today is the industry standard, accounting for over 80% of global leather production being tanned with chromium (III) salts. The remaining 20% is tanned principally using synthetic aldehydes or vegetable extracts. Chromium (III) compounds are highly effective tanning agents, producing leather with a flexible range of properties making it suitable for many end uses. The main chromium compound used for tanning of leather is chromium (III) hydroxide sulphate, Cr(OH)SO₄ (CAS No 12336-95-7; EC No 235-595-8).

Although it is chromium (III) and not chromium (VI) compounds that are used in the leather tanning process, chromium (VI) can be formed from chromium (III) via oxidation, a chemical reaction which can be facilitated by factors like heat, UV radiation, changes in pH,  oxidizing agents and many other factors. The oxidation of chromium (III) to chromium (VI) can be slow which means that articles not containing chromium (VI) directly after production of the leather may develop some hexavalent chromium during transport and storage.

However, best available technologies and good manufacturing practices can minimize the risk of chromium (VI) formation.

Although Germany is currently the only country in the European Union that restricts chromium (VI) in consumer products, in the past few years, many other member states have also recognised the potential health hazards posed by chromium (VI) and notified on the EU’s Rapid Alert System for Non-Food Products, RAPEX, products that contain high levels of chromium (VI) in the leather parts. Enforcement measures so far include rejection of the imported products at border, sales ban, withdrawal of products from the market, seizure of products by authorities and recalling products from consumers. It has been estimated that about 45% of new chromium allergy cases in the EU were caused by exposure to chromium (VI) in leather, thus highlighting the need for a restriction at the European Union level.

In July 2013, the European Commission notified the World Trade Organisation (WTO) the draft Regulation on the restriction of chromium (VI) compounds in leather articles and articles containing leather parts. This draft Regulation will amend the REACH Regulation, expanding the existing restriction on chromium (VI) compounds in cement under Annex XVII.

This proposed restriction began in September 2011 when Denmark notified the European Chemicals Agency its intention to submit a formal proposal to restrict chromium (VI) in leather articles. In accordance with the procedure for new restrictions under REACH, two public consultations then followed (see the ECHA information), and changes were made afterwards to the wording of the original proposal. According to the details in the latest draft Regulation, once the restriction starts to apply, leather articles and articles containing leather parts that come into contact with the skin cannot contain 3 mg/kg or more of chromium (VI) by weight of the total dry weight of that leather part. This means all such articles that come into contact with the skin are within the scope, regardless of the length of time of the contact. Examples of products that are within the restriction scope include: footwear, gloves, articles of clothing, accessories such as hats, belts and braces, watch straps, purses and wallets, bags, horse riding gear, dog leashes, auto seats, covers for car steering wheels, and furniture.

Suppliers have until the new restriction requirement starts to apply in 2015 to take care of their existing stocks on the market that will not comply with the new requirement. Second-hand products that were already in end-use in the EU market before the date of application of the restriction would be exempted. Table A shows the details of the upcoming restriction.

The recommended testing method is EN ISO 17075, which is unfortunately currently the only internationally recognised analytical method available to detect chromium VI in leather. The limit of the proposed restriction is based on the detection limit of this method, which is 3 mg/kg. Since this method is based on Colorimetry, coloured leather samples require special sample pretreatment.  Techniques with better detection power based on chromatographic separation hyphenated to atomic spectrometric determination such as HPLC-ICP-MS do exist, but unfortunately have not yet been approved by standardization bodies for testing leather samples.