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OSHA Offers Silica Exposure Guide

Monday, June 1, 2009

The Occupational Safety and Health Administration has just released Controlling Silica Exposures in Construction (OSHA 3362-04), a new publication designed to help employees minimize exposure to respirable dust containing crystalline silica. Crystalline silica is known to cause silicosis, a serious lung disease, and several groups have asked OSHA to ban its use in abrasive blasting.

The 72-page booklet addresses the control of employee exposures to dust containing crystalline silica;

The book is divided into nine sections that cover different construction operations. Eight are for specific equipment or operations: Stationary Masonry Saws, Handheld Masonry Saws, Hand-Operated Grinders, Tuckpointing/Mortar Removal, Jackhammers, Rotary Hammers and Similar Tools, Vehicle-Mounted Rock Drilling Rigs, and Drywall Finishing. The other section addresses general housekeeping operations and dust control through the use of dust suppressants.

The sections include case studies, reference lists and technical notes. They offer information, advice and recommendations on using wet methods, vacuum dust collection (VDC) systems, and work practices to control dust emissions from construction operations.

Quartz is the most common form of crystalline silica. It is present in many materials in the construction industry, such as brick and mortar, concrete, slate, dimensional stone (granite, sandstone), stone aggregate, tile, and sand used for blasting. Other construction materials that contain crystalline silica are asphalt filler, roofing granules, plastic composites, soils, and to a lesser extent, some wallboard joint compounds, paint, plaster, caulking and putty.

OSHA notes that some organizations have recommended lower levels than that agency requires. For example, the National Institute for Occupational Safety and Health (NIOSH) recommends that respirable crystalline silica exposures be limited to 0.05 mg/m3 as a time-weighted average for up to 10 hours (NIOSH, 2002). The American Conference of Government Industrial Hygienists (ACGIH) recommends that respirable crystalline silica exposures be limited to 0.025 as an 8-hour time-weighted average (ACGIH, 2008).

OSHA is reviewing the construction and general industry PELs for silica in its ongoing silica rulemaking.

Meanwhile, the agency encourages employers to conduct periodic exposure monitoring to confirm that engineering and work practice controls are effective and that appropriate respiratory protection is being used where necessary.

For additional information about controlling silica exposures in construction, please see OSHA’s website at http://www.osha.gov/SLTC/constructionsilica/index.html.

On April 28, the International Safety Equipment Association and the Risk and Insurance Management Society petitioned OSHA to prohibit the use of silica in abrasive blasting. The petition asked for an expedited rulemaking to amend regulations and make the use of silica sand in abrasive blasting a prohibited practice.

To download the book, visit www.osha.gov and see New for Workers under In Focus on the home page.