Ökotest, Issue 10/2011: In the laboratory analysis of the content of the found replacement plasticizer ATBC and TXIB was more than 1,000 mg / kg. So far it is not possible to give for these substitutes a safe assessment of the risk to humans. In the hexagonal Crayola crayons continue aromatic amines in the mines were found. These amines are part of azo-colors and have been found in animal studies to be carcinogenic. In the black mine the content of the amine 3.3-dichlorobenzidine was even more 100 milligrams (depreciation from 5 mg / kg). The test result in the ingredients was therefore 'insufficient'.