What is a restricted substance?
Many substances are restricted for use in industry and consumer products.  Their use is limited for a number of reasons including consumer safety, worker safety and environmental issues (water toxicity or bioaccumulation for example). Certain chemicals are now restricted by legislation and so must not be present in consumer products. Others are restricted by brands and eco-labels.
What restricted substances should I test for?
This is not a simple question to answer! The number of substances that can be restricted is vast and not all of the compounds listed are appropriate for leather or leather products. The answer will depend upon the product you are producing, who it is aimed at (adults or children) and where it is to be sold.  BLC can provide advice in this area and aims to ensure that the information provided is accurate and balanced (for example only suggesting testing where it is deemed appropriate). The most common substances that should be considered when carrying out restricted substance testing are:

  • Chromium VI
  • Banned Azo dyes
  • Formaldehyde
  • Pentachlorophenol
  • Nonylphenol ethoxylates (NPEOs)
  • Cadmium
  • Lead
  • Organotin compounds

How many samples should I test?
Again there is not a simple answer to this question. To test all products would be prohibitive on grounds of cost and time; however, some testing is required to ensure that legislative requirements are being met.
Our recommended structure uses a simple model that includes tests for new suppliers (type), regular testing (batch) for existing suppliers and random (due diligence) assessments.

  • Type tests – when selecting a new supplier we recommend a full suite of physical and chemical tests on both leather and product. The scope for this varies depending on the product and its value.
  • Batch tests – once a supplier has been selected, the specification provided and the first batch of leather type tested, the risk is reduced. Therefore, we recommend a reduced scope of tests that will cover the critical elements of product performance. These tests can be undertaken by BLC or conducted in-house in an approved laboratory.
  • Due diligence tests – it is inappropriate to believe that processes will not change over time and a degree of risk management must be taken, especially for restricted substances, which may unknowingly be introduced into the leather or production process by the supplier. Therefore, an element of calculated random testing is introduced into the protocol which is determined by the type, value and numbers of product.

What is a ppm?
This is an abbreviation for ‘parts per million’. 
1ppm is equivalent to 1mg/kg. 
That is, one milligram of a substance per kilogram of leather. To put this in perspective it is roughly equivalent to a credit card lying in a football field or one minute in two years.
What is the limit for chromium VI in leather and what method should I be using?
There used to be a few different methods to test this property of leather but at the end of last year a new method was derived and has become the new international standard:

  • EN ISO TS 17075:2007

The method is based upon the colorimetric determination of Chromium VI and has a detection limit of 3ppm. BLC has historically used the DIN 53314 method so as to have the detection limit of 3ppm, but has now moved over to using this new CEN method. 
What is the limit for NPEO and APEO in leather?
The European Directive 2003/53/EC (amending the Council Directive 76/769/EEC) relating to the use of NP and NPEO is now in force. This applies within European communities to restrict the use of these compounds.
The Directive states the following:
‘Nonylphenol and Nonylphenol ethoxylate may not be placed on the market or used as a substance or constituent of preparations in concentrations equal or higher than 0.1% by mass for the following purposes:

  • Textile and leather processing except:

Processing with no release to wastewater Systems with special treatment where the process water is pre-treated to remove the organic fraction completely prior to biological wastewater treatment (degreasing of sheepskins).’
It is clear that the legislation relates only to the preparations that may be used during leather production. The limit is not intended as a restriction on the final leather or product. However, many eco-labels and brands are introducing their own limits for the presence of NPEO in their final products. The limits imposed vary in each case (from 1000ppm to 30ppm).  
Whilst there is currently no officially recognised test (CEN, ISO or IULTCS) for the determination of NPEOs, BLC has developed a method to analyse for these in leather samples. To ensure that NPEO has not been used within processing we currently recommend that the finished leather should contain less than 100ppm NPEO.
Can I use chrome tanned leather for children’s items?
Any product that is intended for children or is considered appealing to children may be required to meet the EN71 standard. This standard has several parts, one of which, part 3, is related to the extraction of metals from the product. 
EN71-3 is a testing protocol that is intended to mimic the effect of a baby or small child ingesting the product. This involves extracting the leather in a dilute hydrochloric acid solution before analysis by Inductively Coupled Plasma (ICP). 
Due to the nature of chrome tanned leather, it will not pass the requirements of EN71-3.  The dilute acid will begin to strip the chromium tannage.  Therefore, anyone wishing to manufacture a leather item for use by babies and small children should ensure that they use chromium-free leather.
What is RoHS and does it apply to leather?
These regulations came into force on July 1, 2006, and relate to the ‘Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment Regulations 2005.’
Essentially this is legislation related to electrical and electronic equipment and it restricts the levels of certain compounds in these items.  The compounds listed are:

  • Lead
  • Chromium VI
  • Mercury
  • Polybrominated biphenyls
  • Polybrominated diphenyl ethers
  • Cadmium

The limit for each of these is 0.1% by weight in the final material except in the case of cadmium where the limit is 0.01%.
Whilst initially it seems that these regulations would have little relevance to the leather industry, it should be noted that they may have impact on certain leather containing electrical products (watches for example).  Articles of this nature are eventually disposed of as a whole product (ie with the leather strap attached) and so it is necessary that the whole product complies.
It should, however, be noted that within the regulations there is the following statement:
‘Nothing in these Regulations shall affect the application of existing Community legislation and national legislation as regards (a) safety and health requirements; and (b) waste management.’
This, therefore, implies that in the case of chromium VI, for example, the appropriate limit in the leather watch strap is ‘none detected’.
BLC can be contacted for advice related to the implementation of these regulations.
How can we test for the presence of SCCP (short chain chlorinated paraffins)?
The term short chain chlorinated paraffins can be applied to a large number of compounds. European legislation exists to restrict the use of C10-C13 chlorinated paraffins, which are those containing between 10 and 13 carbon atoms. Due to the size and type of these molecules, it is not possible to identify all possible isomers in one test method. At present there is no single approved test method to detect these compounds. Manufacturers have to rely on self certification of products for compliance.
Conclusions
BLC has access to a wide range of information related to restricted substance legislation and this is just a selection of the queries we receive on a daily basis. The next article in this series will deal with all aspects of lead in leather and associated materials. Lead has come under great scrutiny in recent months in light of the toy recall in summer 2007.
For further information contact BLC Leather Technology Centre Ltd on info@blcleathertech.com