TABLE 1.

The predicted percentage and estimated number of workers exposed to silica at least the NIOSH REL in 2014 by five-digit NAICS code^a

NAICS title	NAICS code	Number of inspections with silica samples after data editing	Estimated workers exposedb	Percentage exposedc	90% CIc
Residential building construction	236110	14	30 200	5.05	1.25–8.84
Poured concrete foundation and structure contractors	238110	39	11 400	6.19	3.41–8.96
Commercial and institutional building construction	236220	37	8400	1.67	0.88–2.46
Masonry contractors	238140	157	7700	6.26	4.77–7.75
Testing laboratories	541380	9	6600	5.03	1.16–8.91
Tile and terrazzo contractors	238340	19	5700	12.04	3.51–20.56
Highway, street, and bridge construction	237310	97	3600	1.40	0.98–1.81
All other specialty trade contractors	238990	54	3100	1.45	0.85–2.05
Brick, stone, and related construction material merchant wholesalers	423320	18	3000	10.12	2.91–17.34
Painting and wall covering contractors	238320	31	2700	1.58	0.77–2.39
All other nonmetallic mineral product manufacturing	327990	268	2600	4.46	3.68–5.25
Site preparation contractors	238910	34	1900	0.63	0.18–1.09
Ferrous metal foundries	331510	490	1800	2.59	2.22–2.95
Water and sewer line and related structures construction	237110	13	1400	0.93	0.18–1.67
Other heavy and civil engineering construction	237990	22	1300	1.56	0.66–2.47
Ready-mix concrete manufacturing	327320	41	1300	1.94	0.87–3.01
Drywall and insulation contractors	238310	17	1100	0.52	0.03–1.02
Medical equipment and supplies manufacturing	339110	9	1100	0.41	0.02–0.80
Other concrete product manufacturing	327390	127	700	1.31	0.89–1.74
Clay building materials and refractories manufacturing	327120	121	600	2.81	2.10–3.52
Pottery, ceramics, and plumbing fixture manufacturing	327110	71	400	3.56	2.47–4.66
Coating, engraving, heat treating, and allied activities	332810	78	400	0.33	0.20–0.46
All other general purpose machinery manufacturing	333990	17	400	0.27	0.05–0.49
Concrete pipe, brick, and block manufacturing	327330	59	300	1.07	0.51–1.63
Pump and compressor manufacturing	333910	15	300	0.51	0.14–0.87
Asphalt paving, roofing, and saturated materials manufacturing	324120	24	200	0.74	0.24–1.25
Glass and glass product manufacturing	327210	56	200	0.29	0.16–0.41
Nonferrous metal foundries	331520	208	200	0.39	0.27–0.50
Plate work and fabricated structural product manufacturing	332310	60	200	0.12	0.08–0.17
Paint and coating manufacturing	325510	21	100	0.25	0.01–0.50
Other plastics product manufacturing	326190	24	100	0.04	0.00–0.07
Abrasive product manufacturing	327910	23	100	0.40	0.08–0.71
Iron and steel mills and ferroalloy manufacturing	331110	35	100	0.13	0.06–0.20
All other fabricated metal product manufacturing	332990	21	100	0.04	0.00–0.07
Agriculture implement manufacturing	333110	11	100	0.11	0.02–0.19
Mining and oil and gas field machinery manufacturing	333130	14	100	0.15	0.04–0.27
Commercial and service industry machinery manufacturing	333310	14	100	0.14	0.02–0.25
Ship and boat building	336610	18	100	0.06	0.02–0.10
			99 700

Abbreviations: CI, confidence interval; NAICS, North American Industry Classification System; NIOSH, National Institute for Occupational Safety and Health; REL, recommended exposure limit.

^aThis does not account for respirator use.

^bRounded to the nearest 100 workers.

^cRounded to the nearest 100th percent.