Table 3.

Summary of respirable quartz levels by plant and job group, exposure intensity in samples collected with 6–8 h sampling time

Job group	Respirable quartz (μg m−3)
	Plant A							Plant B							Plant C
	Unadjusted					Adjusteda		Undjusted					Adjusteda		Unadjusted					Adjusteda
	Nb	Kc	AM	GM	GSDd	GM	P95e	Nb	Kc	AM	GM	GSDd	GM	P95e	Nb	Kc	AM	GM	GSDd	GM	P95e
Furnace
Mix	13	3	14	13	1.5	13	22								9	4	15	10	2.4	9.6	30
Charger															9	5	10	8.0	2.0	8.0	58
Charger/mix															10	5	21	13	2.9	12	12
Payloader	7	2	4.0	3.3	2.0	3.1	7.9	5	1	NA	NA	NA	NA	NA	17	9	3.5	2.5	2.4	2.5	33
Crane	23	7	NA	NA	NA	NA	NA	17	5	3.6	2.1	3.5	2.1	11	13	5	3.4	1.1	3.1	1.1	6.5
Control room	19	6	3.0	2.5	2.0	2.3	7.0	19	5	2.6	1.9	2.4	1.9	11	19	7	2.1	1.7	2.0	1.7	6.5
Cleaning	2	1	23	20	2.1	20	34
Sorting	20	5	NA	NA	NA	NA	NA	18	4	2.4	1.2	4.3	1.2	8.7	18	9	6.6	4.3	3.4	4.4	22
Processing
Refinery
Crusher	29	11	2.8	1.2	4.9	1.2	9.0	13	3	1.7	0.51	7.2	0.49	8.4	19	6	2.6	1.8	2.8	1.9	9.8
Other	27	11	NA	NA	NA	NA	NA	26	14	1.8	0.90	4.5	0.88	6.1	31	8	2.3	0.93	6.5	1.1	6.5
Fines	20	14	NA	NA	NA	NA	NA	56	22	1.5	0.42	7.8	0.44	5.1	48	15	NA	NA	NA	NA	NA
Maintenance
Mechanics	47	17	1.8	0.67	5.3	0.75	5.1	48	18	17	1.5	5.2	1.5	45	28	9	NA	NA	NA	NA	NA
Electrician	20	7	2.3	1.5	2.8	1.5	8.0	20	7	17	2.3	7.3	2.4	123	10	5	NA	NA	NA	NA	NA

The Norwegian OEL for respirable quartz is 100 μg m⁻³ (The Norwegian Labour Inspection Authority, 2007).

NA, not applicable, all measurements below limit of detection (5.2 μg m⁻³ for 8-h sampling time).

^aAdjusted with mixed effect models.

^bNumber of measurements.

^cNumber of persons.

^dGeometric standard deviation.

^e95th percentile.