2025/01/01 by Hartwig, Andrea, MAK Commission
Biochemistry, Genetics and Molecular Biology · Environmental Science · Medicine · #(1-Methylethyl)benzene #(Propan-2-yl)benzen #(Propan-2-yl)benzene #1-Methylethylbenzol #2-Phenylpropan #2-Phenylpropane #571.95 Toxicology #571.95 Toxikologie #616.9803 Betriebs- und Arbeitsmedizin #616.9803 Industrial and occupational medicine #Carcinogens and Genotoxicity Assessment #Cumen #Cumene #Cumol #Effects and risks of endocrine disrupting chemicals #Entwicklungstoxizität #Hautresorption #Isopropyl benzene #Isopropylbenzene #Isopropylbenzol #Kanzerogenität #Leber #Luft #Lunge #MAK value #MAK-Wert #Nase #Occupational exposure and asthma #Reizwirkung #Spitzenbegrenzung #air #carcinogenicity #developmental toxicity #irritation #iso-Propylbenzol #liver #lung #maximale Arbeitsplatzkonzentration #maximum workplace concentration #nose #peak limitation #skin absorption
paper · doi:10.34865/mb9882d0064_w
openalex publication_date 2025/01/01 · openalex created_date 2025/12/13 · openalex updated_date 2026/07/01
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) for isopropyl benzene [98‐82‐8]. Critical effects after repeated inhalation exposure to isopropyl benzene are the induction of tumours in the lung of mice and in the nose of rats as well as effects on the liver in these species. The classification of isopropyl benzene in Category 3 B for carcinogenic substances is retained. Based on the increased liver weight in a 14‐week inhalation study with rats, a MAK value of 10 ml/m3 has been set. This value is now reaffirmed even considering the increased respiratory volume at the workplace (see List of MAK and BAT values, chapters I b and I c). As there was a change in the Commissions evaluation on the adversity of increased liver weight, the new evaluation is based on the lower confidence limit of the benchmark dose (BMDL) of 42 ml/m3 for nasal adenoma in male rats in a two‐year inhalation study. As there is no new data, Peak Limitation Category II with excursion factor of 4 is retained and isopropyl benzene remains assigned to Pregnancy Risk Group C. Isopropyl benzene also remains designated with an “H” (for substances that can be absorbed through the skin in toxicologically relevant amounts).