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Toxicological information

Carcinogenicity

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Description of key information

Oral NOAEL: 542 mg/kg bw/day (chronic; rat)
Dermal application: no reasons of concern about the carcinogenicity potential.

Key value for chemical safety assessment

Carcinogenicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
523.9 mg/kg bw/day
Study duration:
chronic
Species:
rat

Carcinogenicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Carcinogenicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed

Additional information

In a combined chronic / carcinogenicity studies the test substances (CAS 16090-02-1) was administered to 50 Wistar rats/sex/dose in diet at dose levels of 0, 100, 1000, 10000 ppm for 24 months. There were no compound related effects in mortality, clinical signs, body weight, food consumption, haematology, clinical chemistry, urinalysis, organ weights, or gross and histologic pathology. The NOAEL is for females and males 10000 ppm/day. The various statistically significant differences observed with CAS 16090 -02 -1 (increase/decrease) in organ weights (absolute in males), number of reticulocytes/trombocytes, and ALAT (GPT) activities and serum protein were considered to be of no toxicological relevance and did therefore not provide any evidence of toxicity of the test substance at any of the dose levels tested. At the doses tested, there were in tested substances not a treatment related increase in tumour incidence when compared to controls (Bayer AG 1978).

Further studies were done in order to investigate whether the test substance has a carcinogenic effect onto skin under light exposure: they investigating the increase or the appearance of skin tumours after several ultraviolet light exposures after dermal exposure to the substance. The experiments conducted did not evidence any reason of concern about the carcinogenicity potential.


Justification for selection of carcinogenicity via oral route endpoint:
Test procedures are well documented and scientifically acceptable.

Justification for selection of carcinogenicity via dermal route endpoint:
No reliable key study can be identified, because of major deficiencies in all of them, neverheless all studies give a clear indication of no dermal cancerogenicity potentiality via dermal route

Justification for classification or non-classification

According to the CLP Regulation (EC 1272/2008), 3.6 Carcinogenicity section,carcinogen means a substance which induce cancer or increase its incidence. Substances which have induced benign and malignant tumours in well performed experimental studies on animals are considered also to be presumed or suspected human carcinogens unless there is strong evidence that the mechanism of tumour formation is not relevant for humans. For the purpose of the classification for carcinogenicity, substances are allocated to one of two categories (known or presumed human carcinogens and Suspected human carcinogens) based on strength of evidence and additional considerations (weight of evidence). In certain instances, route-specific classification may be warranted, if it can be conclusively proved that no other route of exposure exhibits the hazard

In conclusion, the available experimental data are adequate for classification and labelling and the substance is not classified for carcinogenicity according to the CLP Regulation (EC 1272/2008).