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Toxicological information

Carcinogenicity

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Description of key information

In two NTP inhalation studies groups of fifty F344/N rats and fifty B6C3F1 mice of each sex  were exposed to tetrahydronaphthalene for 6 h per day for 5 days per week at levels of 0, 30, 60 and 120 ppm.
For non-neoplastic local effects the LOAEC was 30 ppm (165 mg/m³; nasal effects) in rats, for systemic non-neoplastic effects the NOAEC was 30 ppm (165 mg/m³; cardiomyopathy at higher dose levels) in rats.
Increased incidence of hepatocellular adenoma and carcinoma and stromal polyps of the uterus in female rats was observed. A NOAEC for carcinogenicity was noted at 60 ppm (330 mg/m³).
Based on the lack of genotoxic activity in an array of genotoxicity studies THN is not considered to be a genotoxic cancerogen.

Key value for chemical safety assessment

Carcinogenicity: via inhalation route

Endpoint conclusion
Dose descriptor:
NOAEC
330 mg/m³

Additional information

Under the conditions of these 2-year inhalation studies, there was some evidence of carcinogenic activity of tetralin in male F344/N rats based on the increased incidence of cortical renal tubule adenoma.

The increased incidence of testicular interstitial cell adenoma may have been related to tetralin exposure. There was some evidence of carcinogenic activity of tetralin in female F344/N rats based on the increased incidences of hepatocellular neoplasms (adenomas and adenomas or carcinomas combined) and uterine stromal polyp.

There was no evidence of carcinogenic activity of tetralin in male B6C3F1 mice exposed to 30, 60 or 120 ppm.

There was equivocal evidence of carcinogenic activity of tetralin in female B6C3F1 mice based on the increased incidence of splenic hemangiosarcoma.

Exposure to tetralin resulted in nonneoplastic lesions of the nose in male and female rats and mice, kidney and testis in male rats, uterus in female rats, and urinary bladder in male and female mice

For systemic non-neoplastic effects the NOAEC was 30 ppm (165 mg/m³) based on increased incidence of cardiomyopathy in female rats at higher dose levels was noted.

Increased incidence of hepatocellular adenoma and carcinoma and stromal polyps of the uterus in female rats was observed. A NOAEC for carcinogenicity was noted at 60 ppm (330 mg/m³).

Based on the lack of genotoxic activity in an array of genotoxicity studies THN is not considered to be a genotoxic cancerogen.

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Carcinogenicity: via inhalation route (target organ): digestive: liver; urogenital: uterus

Justification for classification or non-classification

Based on mechanistic considerations renal tubule adenoma observed in male rats are considered not relevant for human cancer risk.

No carcinogenic effects were noted in mice. Increased incidence of hepatocellular adenoma and carcinoma and stromal polyps of the uterus in female rats was observed. A NOAEC for carcinogenicity was noted at 60 ppm (330 mg/m³).

Based on the lack of genotoxic activity in an array of genotoxicity studies THN is not considered to be a genotoxic cancerogen.

A classification with R40 Carcinogen Cat 3 corresponding to Carcininogen Class 2, H351 is proposed.