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Administrative data

Description of key information

Key value for chemical safety assessment

Carcinogenicity: via oral route

Endpoint conclusion
Dose descriptor:
5.9 mg/kg bw/day

Justification for classification or non-classification

Classification according to Annex I of the directive 67/548/EEC - 26. ATP

Category 2 carcinogen

R45 May cause cancer.

By CLP as Carc Cat 1B May cause cancer.

Additional information

For 2,4-TDA valid long-term feeding studies in rats and mice are available similar to OECD TG 451.

Oral intake to rats at doses of 5.9 mg/kg bw/day 2,4-TDA and more over a period of up to 103 weeks lead to a dose dependent increase of hepatocellular carcinomas or neoplastic nodules  in both sexes. In addition, 2,4-TDA induced adenomas and carcinomas of the mammary gland in females as well as fibromas of the subcutaneous tissue and an increased incidence of  lung tumors (although statistically not significant) in males (NCI 1979, Cardy 1979, Sontag 1981, Ito et al. 1969, Stula and Aftosmis 1976). In mice hepatocellular carcinomas occurred significant in females after oral application of doses of 15 and 30 mg/kg bw/day for 101 weeks. In addition, oral long-life administration of 2,4-TDA may have increased the incidence of lymphomas in female mice. Neoplasms of the lung seen as adenomas and/or adenocarcinomas, and of the hematopoietic system were slightly increased in male mice. But no tumors occurred at significantly increased incidences in male mice (NCI 1979, Reuber 1979).

In summary, 2,4-TDA was carcinogenic in rats and mice after oral long-term administration.

Carcinogenicity: via oral route (target organ): cardiovascular / hematological: hematopoiesis; digestive: liver; glandular: mammary gland; respiratory: lung; other: skin