The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated decahydronaphthalene to derive a maximum concentration at the workplace (MAK value), considering all toxicity endpoints. Available study reports and publications are described in detail.
In animal studies, the primary target organ of the toxicity of decahydronaphthalene is the kidneys. The α2u‐globulin nephropathy observed in male rats after exposure to decahydronaphthalene is species and sex‐specific and is therefore not taken into account for the evaluation. The most sensitive end point was the increased LDH activity in the urine of female rats in the 14‐week inhalation study. A calculation yielded a lower confidence limit of the benchmark dose (BMDL) of 12 ml/m3 related to an increase by one standard deviation of the control value. As this value was obtained from animal studies, a MAK value of 5 ml/m3 can be derived according to the procedure of the Commission. As the critical effect is systemic and the half‐life in the kidneys of female rats is about 1 to 2 hours, Peak Limitation Category II with the excursion factor of 2 is assigned.
In the only available developmental toxicity study, no adverse effects were detected in the offspring of female mice treated with decahydronaphthalene, but teratogenicity was not investigated. The available data is therefore judged to be insufficient and the substance is classified in Pregnancy Risk Group D.
Decahydronaphthalene is not regarded to be genotoxic. In carcinogenicity studies, male F344 rats developed kidney tumours caused by α2u‐globulin nephropathy, which has no relevance for humans. Increased incidences of hepatocellular carcinomas were seen in female B6C3F1 mice, but only at the low concentration group. Decahydronaphthalene is therefore not classified in any of the carcinogen categories. Decahydronaphthalene is not a contact sensitizer in guinea pigs and there are no clinical findings available that would substantiate sensitizing effects on the skin or respiratory tract. Skin contact is not expected to contribute significantly to its systemic toxicity.