Registration Dossier

Administrative data

Description of key information

The registered substance is subject of a harmonized classification as Carc 1B/H350. This is confirmed by experimental data showing tumour formation at various sites in two strains of mice and in hamsters.

Key value for chemical safety assessment

Carcinogenicity: via oral route

Endpoint conclusion
Dose descriptor:
LOAEL
8.8 mg/kg bw/day

Carcinogenicity: via inhalation route

Endpoint conclusion
Dose descriptor:
NOAEC
0.038 mg/m³

Additional information

Key dose-levels and target organs have been compiled from following secondary citation sources:

- CPDB (http://potency.berkeley.edu/chempages/METHYLHYDRAZINE.html);

- HSDB and TOXNET;

- US EPA's AEGL documents (http://www.epa.gov/oppt/aegl/pubs/tsd4.pdf);

- OEHHA's derivation of NSRL (http://www.oehha.org/prop65/law/pdf_zip/MethylhydrazineNSRL.pdf) - NB: their recalculated dose-levels were considered more reliable in case of discordance with other sources

Precisions on organs and tumor types observed:

Hamster, oral (drinking water):

- liver: malignant histiocytoma (M+F)

- cecum: various tumours (M+F)

Hamster, inhalative (sex not indicated):

- nasal polyps and adenomas

- benign adrenal adenomas

Mouse, oral (drinking water):

- liver: various tumours (M) or hepatoma (F)

- bile duct: various tumours (M+F)

- lung: various tumours (F)

Mouse, inhalative (sex not indicated):

- lung tumours, nasal adenoma, nasal polyp, nasal osteoma,

- hemangioma,

- liver adenoma and carcinoma

Dog and Rat, inhalative (M+F): negative but exposure only lasted 1 year

Key carcinogenicity endpoints:

- LOAEL oral (drinking water), lifetime= 22 (M) - 28 (F) mg/kg/day in Swiss mice (Toth 1972) and 8.8 (M) - 12 (F) mg/kg/day lifetime in Syrian golden hamsters (Toth and Shimizu 1973)

- NOAEC inhalation, 1 year exposure only (Kinkead 1985) = 5 ppm in M/F F344 rats, 0.02 ppm (LOAEC: 0.2 ppm) in F C57BL/6 mice and 0.2 ppm (LOAEC: 2 ppm) in M Syrian Golden hamsters. 1 ppm = 1.9 mg/m3 at 20 -25°C, atmospheric pressure.

Carcinogenicity: via inhalation route (target organ): cardiovascular / hematological: other; digestive: cecum; digestive: liver; digestive: other; glandular: adrenal gland; respiratory: lung; respiratory: nose

Justification for classification or non-classification

The registered substance is subject of a harmonized classification as Carc 1B/H350.