Abstract

The introduction in July 1994 by the German parliament of an amendment to their Consumer Goods Act, which prohibited certain azo dyes, has had consequences world-wide at all levels of the leather industry. The general thrust behind the law has strong support at all levels in the industry but the fine details have caught many unaware of their practical implications.

The German law makers have found they needed several further amendments to bring even some degree of workability to the legislation. The test institutes world-wide have discovered an exceedingly lucrative new business niche in chemical analyses. Those in the leather manufacturing chain, from tanners all over the world through to the German retail shops, have faced frustration. They have been struggling to come to grips with the practicalities of a law that was introduced without a valid test method to enforce it. At the other end of the chain the azo dye manufacturers have had to subject their products to analytical scrutiny at the parts per million level and have discovered the limits of analytical methods.

The German Act prohibits the use of certain azo dyes in defined consumer goods that come into repeated contact with the skin. The azo dyes affected by this legislation are those that after splitting up of the dye molecule at the azo groups release any of the 20 amines listed in the Act.

Those involved in developing the analytical method quickly discovered it is easy to legally define this splitting up of dye molecules, but in practice much more difficult to implement so that only amines from the splitting of the azo group were detected. Dye molecules are happy to split in other ways if the reaction conditions are sufficient. Any type of correlation with the real life in visa reduction reactions was never considered as the analysts struggled within strict time constraints to produce a German standard test method.

The manufacture of a dye today, taking into account all the constraints of the above legislation, can lead to “clean” dyes being labelled as doubtful. The manufacturing process of a dye will be followed to show how such a situation could arise. It is clear that there are still areas of greyness in the Act as it stands, but the rapid expansion of this type of legislation within Europe means that all in the leather industry will have to work with the current political, commercial and analytical compromise situation.