German Legislation on Azo Dyes Environmental protection and product DyStar's products are continuously mo- safety are becoming increasingly impor- nitored to make sure they meet statutory tant criteria in the purchase of textiles, requirements throughout the world. due to the emotive nature of the debate and greater consumer concern. DyStar sets standards in environmental responsibility. DyStar has not had to This publication provides general infor- make any changes to its product range mationaboutazodyestohelpputthe to comply with the amendments to the issue on a more factual basis. Here you German Consumer Goods Ordinance. will find some background notes about What better evidence could there be that the German Consumer Goods Ordinance, together with a list of the amines and with DyStar products dyestuffs involved. Information is also you’re on the safe side. provided about the test methods used for textiles, as well as an overview of other By buying and using dyes and pigment national regulations relating to azo dyes. preparations from DyStar, you can be sure you comply with the German Consumer Goods Ordinance and other statutory regulations. None of our azo dyes generate banned amines following azo bond cleavage. So consumers can be confident that textiles dyed and printed correctly with DyStar products are safe. Contact us if you would like further information. Your local DyStar representative or our central ecology team will be happy to help you. CONTENTS ECOLOGY Toxicological background 2 List of „banned“ azo dyes 7 Azo dyes 3 Azo pigments 8 The German Consumer Goods Ordinance 4 Consumer goods 8 Listed amines 5 International legislation 9 Draft for 6th Amendment 5 Annex: Analytical detection Tables of „banned“ of „banned“ azo dyes 6 azo colourants 12 Azo dyestuffs Amendments to the German affected by the ban. But even the experts Consumer Goods Ordinance could not agree about the details of the law, because some single regulations and phra- In 1994, the German Consumer Goods ses were rather vague. Ordinance (Bedarfsgegenständeverordnung) was amended to ban specific azo dyes, triggering widespread discussion about Toxicological background textile ecology. The German amendment also had an international impact, with MAK amines headlines such as “German Azo Ban”. Textile finishers and the trade were The first serious reports about an increased confronted overnight with a ban on azo risk of cancer of the bladder for people dyes which release specific amines as a working in dyestuff production were pub- result of reductive cleavage of azo bonds. lished in trade journals as long as 100 years previously. The cause of these malignant This definition was only understood by dye diseases was soon thought to be certain chemists initially, as only these experts had aromatic amines widely used in the pro- a concrete idea which dyestuffs would be duction of synthetic dyes in those days. Figure 1 – Synthesis of Azo Dyes Figure 2 – Reductive Cleavage of Azo Dyestuffs 1) The MAK list was set up by the German Senate Committee for Testing of Occupational Hazardous Substances, and is updated annually (MAK = maximum workplace concentration). Group III of the MAK list summarizes carcinogenic chemicals (for carc. cat. 1 and 2 substances no max. tolerable workplace concentration is specified, though). The earlier divisions A1 and A2 of Group III have been renamed Category 1 and Category 2 2 in 1998, in keeping with the EU classification system for carcinogenic substances. Azo dyestuffs In particular, benzidine (basis of benzidine reduction in some organs. Several studies dyes) was thought to play a leading role. carried out with textile workers handling benzidine dyes showed the presence of Today scientifically based epidemiological traces of free benzidine in the urine. MAK evidence shows that four aromatic amines amines released in the human organism have a carcinogenic effect in humans: from azo dyestuffs can have a carcinogenic effect there. Epidemiological studies exist ● benzidine which describe an increased incidence of ● 2-naphthylamine carcinomas of the bladder among painters ● 4-aminodiphenyl and dye factory workers who had never ● 4-chloro-o-toluidine had contact with free MAK amines, but only with the related azo dyes. It should These four compounds are listed as “sub- be emphasized here that benzidine dyes stances definitely known to be carcinogenic and “MAK-dyes” in general can only have in humans” in Category 1, Section III of the a carcinogenic effect where there is suffi- MAK1) list. cient exposure, i.e., when these dyes actu- ally enter the human organism as a result Animal studies have shown that other aro- of improper handling or low occupational matic amines are also carcinogenic under safety standards. conditions, such as would indicate a carci- nogenic potential for humans too. These The German Law on Hazardous Sub- substances make up Category 2, Section III stances classifies those azo dyes as carcino- of the MAK list. genic where a carcinogenic arylamine can be formed following reductive azo Azo dyes cleavage. The strict workplace protection rules which apply when handling carcino- Azo dyes are synthesized by the diazoti- genic substances apply to these dyes, too. zation of aromatic amines, followed by The MAK Committee recommends that all coupling to a further aromatic compound azo dyes which can form MAK amines (known as the coupling component). This following cleavage should be avoided in results in the formation of the so-called azo general. German legislation has adopted group – two nitrogen atoms joined by a this recommendation in TRGS 6142) double bond — N = N — (see Figure 1). “Technical Regulation for Hazardous Substances”, thereby putting this into effect. Azo groups in dyestuffs can be easily This recommendation is widely followed clea-ved using a reducing agent, which in Germany. DyStar as well as its parent results in the decolorization of the azo dye. companies stopped producing and marke- As a result of this azo cleavage, the aro- ting benzidine dyes in 1971. Marketing matic amine that had been used as a diazo of other dyes based on Cat. 1 or 2 amines component in the dyestuff synthesis is set of the MAK list also ceased several years free again; also the coupling component is ago. However, numerous non-traditionals released, but now substituted with an addi- still produce and market these dyes world- tional amino group (see Figure 2). This wide and even in Europe today. reaction can be technically useful else- where. 2) TRGS: Technische Regeln für Gefahrstoffe (= Technical Regu- lation for Hazardous Substances). Up to May 1999, the TRGS 614 Over the last 40 years, additional evidence contained a list of 20 carcinogenic amines (identical with the German Consumer Goods Ordinance list, see Table 1). From May has accumulated that azo dyes can also 1999, four further amines were added to the TRGS list: 6-amino- 2-ethoxy-naphthaline; 4-amino-3-fluorophenol; 2-methoxyanaline be metabolically cleaved by bacteria in the (o-anisidine); p-amino azobenzene. Only the last two mentioned amines, already classified by the EU as carcinogenic since years, human digestive tract or by enzymatic are relevant to dyes. 3 Azo dyestuffs The German Consumer Goods Amendments to the Consumer Ordinance Goods Ordinance Implementation of the recommendations Nevertheless, with preventative consumer of the MAK Committee and the TRGS 614 protection in mind, the German Consumer not to use dyestuffs based on MAK amines, Goods Ordinance was amended in 1994 together with the strict workplace protec- to prevent any potential health risk from tion rules of the Hazardous Substances Law textiles dyed with dyestuffs based on and corresponding EU Directives, offers an cleavable carcinogenic amines. The effective protection to dye factory workers amendment to the regulations then read: from health risks which could result from inhalation of dust-forming “MAK dyes” or from direct skin contact with these dyes “Textiles and other articles with where they are still in use. prolonged skin contact shall not be dyed with azo dyestuffs which, After textiles have been dyed, azo dyestuffs by cleavage of one or more azo based on MAK amines do not represent bonds, can release any of 20 listed a real health risk to the consumer. In order aromatic amines. Furthermore, to enter the consumer’s organism, the dye such textiles may not be imported must migrate from the textile to the skin, or brought into circulation.” and must then be absorbed by the body through the skin. This risk is negligible where the fastness of the dye is high enough. The regulations were re-amended several times over the next few years due to pro- A genuine risk may exist where babies or blems with the wording of the regulation, infants suck on textiles or soft toys so that and other difficulties in the enforcement traces of the dye can enter the body with the of the statutory transition periods. saliva. As of April 18, 1997 the current 5th amend- ment to the Consumer Goods Ordinance came into force: Annex 1, No. 7 column 3 of the German Consumer Goods Ordinance, as of 18. 4. 1997 presp. 23. 12. 1997 (abbreviated): “The following may not be used in the commercial production or treatment of con- sumer goods: Azo dyestuffs which, on cleavage of one or more azo groups, release any of twenty listed amines (see list in Table 1). Pigments are exempted from this regulation, provided none of the following amines (see list in Table 1) can be detected after cleavage of one or several azo groups (using the analysis method described in Annex 10, No. 7). Consumer goods which do not comply with these regulations may not be imported or brought into circulation.” 4 Azo dyestuffs Table 1 Listed amines The following 20 aromatic amines are listed in the German Consumer Goods Ordinance.