Pentaborane: MAK Value Documentation, addendum - Translation of the German version from 2024.

The German Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area (MAK Commission) re-evaluated the occupational exposure limit value (maximum concentration at the workplace, MAK value) for pentaborane [19624-22-7] considering all toxicological end points. Relevant studies were identified from a literature search. The critical effect of pentaborane is its effect on the central nervous system (CNS). Inadequately documented studies carried out before 1960 reported findings of CNS effects in humans at concentrations below 1 ml/m3 and in various animal species at the lowest concentration tested of 0.2 ml/m3 and above (exposure period: 6 months). In rats, guinea pigs, rabbits, dogs and monkeys, mortality was also observed at this concentration. As a result, no MAK value can be derived. Pentaborane, which is a liquid at room temperature, does not penetrate the skin in toxicologically relevant amounts. There are no studies investigating developmental toxicity, genotoxicity, carcinogenicity or the sensitizing potential of pentaborane.