Azo Testing

Azodye almost exists in all colours as one of the most widely-used synthetic dyestuffs in printing technique (for textiles). It is used for dyeing and printing of natural and synthetic fibres, also for the colouring of paints, plastics and rubber.
When textiles, garments and leather articles come into direct contact with the skin, some azodyes will decompose into arylamines having carcinogenic properties (i.e. carcinogenic azodyes) when they blend with metabolite (perspiration) of human body. However, it presents great hazard if carcinogenic azodyes are absorbed by human bodies. For the purpose of clarity, there are as many as 3,000 azodyes in use and most of them are safe. Only about 200 azodyes are forbidden as they can be reduced to release arylamineshaving carcinogenic properties.
 

Regulations
EU REACH Annex XVII
Oeko-Tex®Standard 100
China GB 18401 National General Safety Technical Code for Textile Products
Other related regulations
 
Arylamines having carcinogenic properties:

SN	Substance	CAS number
1	4-aminobiphenyl	92-67-1
2	benzidine	92-87-5
3	4-chloro-o-toluidine	95-69-2
4	2-naphthylamine	91-59-8
5	o-aminoazotoluene	97-56-3
6	5-nitro-o-toluidine	99-55-8
7	p-chloroaniline	106-47-8
8	2,4-diaminoanisole	615-05-4
9	4,4′-diaminobiphenymethane	101-77-9
10	3,3′-dichlorobenzidine	91-94-1
11	3,3′-dimethoxybenzidine	119-90-4
12	3,3′-dimethylbenzidine	119-93-7
13	3,3′-dimethy1-4,4′-diaminobiphenylmthane	838-88-0
14	p-cresidine	120-71-8
15	4,4′-methylene-bis-(2-chloroaniline)	101-14-4
16	4,4′-oxydianiline	101-80-4
17	4,4′-thiodianiline	139-65-1
18	o-toluidine	95-53-4
19	2,4-toluylendiamine	95-80-7
20	2,4,5-trimethylaniline	137-17-7
21	o-anisidine	90-04-0
22	4-aminoazobenzene	60-09-3
23	2,4-xylidine	95-68-1
24	2,6-xylidine	87-62-7