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Toxicological information

Carcinogenicity

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Description of key information

Carcinogenicity studies according to current testing guidelines are not available. A non-conventional long-term study in rats which received diets (bread) made of flour that had been treated with azodicarbonamide (100 mg/kg) showed no clinical signs or treatment-related organ changes. The tumour incidences were unchanged (Oser, 1965). The results can be used as supportive results for the non-classification of ADCA as carcinogenic. 

Key value for chemical safety assessment

Carcinogenicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no study available

Carcinogenicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Carcinogenicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Oral exposure to high concentrations of the primary metabolite of ADCA, biurea (HADA) was achieved in a two year study in rats. There was no evidence of chronic toxicity and no neoplastic change associated with treatment. It is considered that despite the lack of analytical support determining intake, the intake was highly likely to be significant and sufficient to assess the toxic potential of the test material. The group size after 2 years exposure was small, and inadequate to assess the effect on tumour incidence of rare tumour types therefore the study can only be used to provide supporting information. In light of the negative findings it is considered that ADCA has not been shown to have carcinogenic potential after a lifetime exposure in a rodent study.

It is noted that the "Trade Union Priority List for REACH Authorisation" version 2.0 (European Trade Union Institute, June 2010) indicates that ADCA has been identified as a known or probable carcinogen by IARC (International Agency for Research on Cancer). On review of IARC monographs there is no indication that ADCA has ever been reviewed by IARC and this aspect of the scoring indicated in the ETUI document is incorrect.

Justification for classification or non-classification

No dedicated studies investigating the carcinogenic potential of ADCA are available. None of the other available data (repeated dose toxicity studies, reproductive toxicity studies, etc.) indicate a potential for ADCA to promote tumour generation. There is not basis by which to consider that ADCA should be classified as a carcinogen.