Evaluation of dry and wet block cutting and recommendation for a masonry company.
Appl Occup Environ Hyg 2003 Mar; 18(3):145-150
On March 13, 2000, the safety manager representing a masonry company contacted the National Institute for Occupational Safety and Health (NIOSH) to discuss a dust control problem. The company had received an Occupational Safety and Health Administration (OSHA) citation for overexposure of workers to crystalline silica during the dry cutting of brick. The company was cited under the OSHA Permissible Exposure Limit (PEL) for dusts containing crystalline silica. This OSHA PEL is calculated using a formula that reflects the combination of two components: I) level of respirable dust (i.e., dust small enough to penetrate to the air exchange regions of the lung where clearance and detoxification are difficult), and 2) the percentage and type of (e.g., quartz or cristobalite) crystalline silica in the dust. The company had purchased several brick!block cutoff saws equipped with water dust suppression, but was required by OSHA to enroll the operators in a respiratory protection program (fit testing and use of half-mask, cartridge respirators) until they could show that exposures were adequately controlled. On April 3, 2000, NIOSH received a request from the company to conduct a Health Hazard Evaluation (HHE) to assess the effectiveness of wet dust suppression during the cutting of brick and block. On May 8, 2000, NIOSH investigators met with company representatives and discussed the scope of the investigation, reviewed existing environmental and administrative controls, conducted a walk-through ofthe facilities, and examined the equipment. Airborne respirable dust samples using wet and dry cutting methods were collected on May 9 and 10,2000. This article presents the results of this assessment. The effectiveness of using wet dust suppression while cutting brick and block is addressed. Recommendations for preventing exposure to crystalline silica are included.
Masons; Dust-control; Construction-industry; Construction-workers; Exposure-levels; Occupational-exposure; Silica-dusts; Exposure-limits; Respirable-dust; Quartz-dust; Tools; Respirators; Respiratory-protection; Personal-protective-equipment; Sampling
Daniel J. Yereb, National Institute for Occupational Safety and Health, Division of Respiratory Disease Studies, Field Studies Branch, 1095 Willowdale Road, Morgantown, WV 26505
Applied Occupational and Environmental Hygiene