Table 2.

Personal exposure to benzene and 1,3-butadiene (µg/m³) among refinery workers during two turnarounds (a complete and a partial) at Refinery 2

Exposure group	N	% > LOD	Mean	SD	Median	GM	GSD	Range
Benzene
Complete
Refinery workers	26	100	960	1300	210	230	7.5	7–4500
Process technicians	13	100	870	1500	180	220	6.0	23–4500
Other occupationsa	13	100	1100	1200	580	240	9.9	7–3400
Partial
Refinery workers	22	100	150	310	44	52	4.1	7–1200
Refinery employeesb	8	100	34	31	20	23	2.6	7–86
Contractors	14	100	220	380	87	82	4.2	9–1200
1,3-Butadiene
Complete
Refinery workers	26	81	10	12	5.2	4.4	4.3	<LOD-36
Process technicians	13	62	7.7	12	2.2	2.7	4.6	<LOD-35
Other occupationsa	13	92	13	12	6.8	7.2	3.5	<LOD-36
Partial
Refinery workers	22	64	2.8	3.7	1.4	1.6	2.8	<LOD-16
Refinery employeesb	8	63	1.3	0.7	1.4	1.1	1.9	<LOD-2.3
Contractors	14	64	3.7	4.5	1.3	1.9	3.2	<LOD-16

N number of measurements, % > LOD percentage of samples above limit of detection (LOD). LODs were 5 µg/m³ for benzene and 1 µg/m³ for 1,3-butadiene, Mean arithmetic mean exposure (untransformed data), SD standard deviation (untransformed data), GM geometric mean exposure, GSD geometric standard deviation

^aTurnaround coordinators (3 workers), maintenance workers (5 workers), contractors (5 workers) with similar work tasks

^bProcess technicians (5 workers) and engineers (3 workers) with similar work tasks