The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area evaluated tri‐n‐butyl phosphate [CAS No.126‐73‐8] in 2016 and derived a biological reference value (“Biologischer Arbeitsstoff‐Referenzwert”, BAR) for dibutyl phosphate in urine. Available publications are described in detail.
In a study with persons of the general population occupationally not exposed to tri‐n‐butyl phosphate a 95th percentile of 0.67 µg dibutyl phosphate/l urine was measured. Further studies with non‐exposed individuals resulted in maximum levels of 0.45 µg and 0.26 µg dibutyl phosphate/l urine.
Taking these results together with other investigations into consideration, a BAR for tri‐n‐butyl phosphate of 0.5 µg dibutyl phosphate/l urine was established. Sampling time is at the end of exposure or the end of the working shift.