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), the pregnancy risk group, sensitization, absorption through the skin and germ cell mutagenicity of triphenylphosphine [603-35-0]. The critical effect is neurotoxicity which was observed in a four-week study in dogs at a respirable aerosol concentration of 30 mg triphenylphosphine in xylene/m3 with a NOAEC of 10 mg/m3. Based on this and taking into account the increased respiratory volume at the workplace, the MAK value is set at 2 mg/m3 as the inhalable fraction (I). Since a systemic effect is critical, Peak Limitation Category II is retained. The default excursion factor of 2 has been confirmed because the half-life is still not known. There is an adequate margin between the NOAEL for developmental toxicity and the MAK value. However, triphenylphosphine is a neurotoxin and data on developmental neurotoxicity are lacking. Therefore, triphenylphosphine is assigned to Pregnancy Risk Group D. Triphenylphosphine is not mutagenic in bacteria and neither clastogenic in vitro nor in vivo. Skin contact is expected to lead to a relatively minor contribution to systemic toxicity. Triphenylphosphine can cause sensitization of the skin in animals and is therefore designated with “Sh”.
