TY - JOUR T1 - Air exposure assessment of TDI and biological monitoring of TDA in urine in workers in polyurethane foam industry JF - Occupational and Environmental Medicine JO - Occup Environ Med SP - 93 LP - 98 DO - 10.1136/oem.2011.064840 VL - 69 IS - 2 AU - Tom Geens AU - Sandra Dugardin AU - Ann Schockaert AU - Geert De Cooman AU - Marc van Sprundel Y1 - 2012/02/01 UR - http://oem.bmj.com/content/69/2/93.abstract N2 - Objectives Toluene diisocyanate (TDI) is used in the manufacturing process of polyurethane (PU) foams and is a potent inducer of occupational asthma. The objective of this study was to evaluate the correlation between the exposure to total TDI (2,4- and 2,6-TDI) in air and the corresponding biomarker concentration of total TDA (2,4- and 2,6-TDA) in hydrolysed urine. The aim was also to propose an appropriate biological exposure limit for total TDA in urine.Methods 9 workers from two production lines in a PU foam producing plant were studied. Personal exposure to TDI during four representative production shifts was monitored by an active air sampling method (filter impregnated with 1-(2-methoxyphenyl)piperazine) and quantified by high-performance liquid chromatography and diode array detection (NIOSH n° 2535, 5521). In parallel, pre-shift and post-shift urinary samples were collected from the exposed workers, and TDA concentrations were determined by gas chromatography–mass spectrometry after alkaline hydrolysis. All samples were collected on four measuring days: two Fridays (end of workweek) and two Mondays (start of workweek) separated by a weekend without exposure.Results Strong correlations between the personal air concentrations of total TDI and the corresponding biomarker levels of total TDA in urine (r=0.816) were observed. An increase of 18.12 μg TDA/l (post-shift minus pre-shift concentration) corresponds to an exposure of 5 ppb (37 μg/m3, the current American Conference of Governmental Industrial Hygienists threshold limit value) during the shift.Conclusions The increase in TDA during the shift is a suitable biomarker for exposure to TDI during the same shift. Further research is needed to evaluate the use of start of week or end of week post-shift TDA in urine as biomarker since TDA was found to accumulate during the working week and thus the moment of sampling will clearly influence the result. ER -