Excessive exposure to silica in the US construction industry.
Rappaport SM; Goldberg M; Susi P; Herrick RF
Ann Occup Hyg 2003 Mar; 47(2):111-122
Exposures to respirable dust and silica were investigated among 36 construction sites in the USA. Personal measurements (n = 151) were analyzed from 80 workers in four trades, namely bricklayers, painters (while abrasive blasting), operating engineers and laborers. Painters had the highest exposures (median values for respirable dust and silica: 13.5 and 1.28 mg/m(3), respectively), followed by laborers (2.46 and 0.350 mg/m(3)), bricklayers (2.13 and 3.20 mg/m(3)) and operating engineers (0.720 and 0.075 mg/m(3)). Mixed models were fitted to the log-transformed air levels to estimate the means and within- and between-worker variance components of the distributions in each trade. We refer to the likelihood that a typical worker from a given trade would be exposed, on average, above the occupational exposure limit (OEL) as the probability of overexposure. Given US OELs of 0.05 mg/m(3) for respirable silica and 3 mg/m(3) for respirable dust, we estimated probabilities of overexposure as between 64.5 and 100 percent for silica and between 8.2 and 89.2 percent for dust; in no instance could it be inferred with certainty that this probability was less than 10 percent. This indicates that silica exposures are grossly unacceptable in the US construction industry. While engineering and administrative interventions are needed to reduce overall air levels, the heterogeneous exposures among members of each trade suggest that controls should focus, in part, upon the individual sites, activities and equipment involved. The effects of current controls and workplace characteristics upon silica exposures were investigated among operating engineers and laborers. Silica exposures were significantly reduced by wet dust suppression (approximately 3-fold for laborers) and use of ventilated cabs (approximately 6-fold for operating engineers) and were significantly increased indoors (about 4-fold for laborers). It is concluded that urgent action is required to reduce silica exposures in the US construction industry.
Quartz-dust; Silica-dusts; Respirable-dust; Dust-control; Dust-control-equipment; Dust-exposure; Dust-particles; Dusts; Control-technology; Control-methods; Engineering-controls; Construction; Construction-equipment; Construction-industry; Construction-materials; Construction-workers; Particulate-dust; Concretes; Cements; Sampling; Air-samples; Employee-exposure; Exposure-assessment; Machine-operators; Equipment-operators; Exposure-levels; Exposure-limits; Permissible-limits;
Author Keywords: construction industry; controls; dust; mixed models; overexposure; silica; variance components
S.M. Rappaport, School of Public Health, University of North Carolina, Chapel Hill, NC 27599-7431, USA
Cooperative Agreement; Construction; Grant
Annals of Occupational Hygiene
The Center to Protect Workers' Rights