The study of silica: Part one

The federal government's strict silica regulation has pushed NRCA into action

Editor's note: The following article is part one of a two-part series. Part two will be published in the March issue and address roofing exposures to silica in more detail.

The Occupational Safety and Health Administration (OSHA) began fully enforcing its new regulation regarding worker exposure to respirable crystalline silica (RCS) Oct. 23, 2017. In December 2017, a three-judge panel of the U.S. Court of Appeals for the D.C. Circuit rejected oral arguments from industry groups that had filed suit against OSHA to stop the RCS rule from being implemented. As a result, OSHA's enforcement remains in full swing.

According to OSHA, about 2.3 million workers are exposed to RCS in their workplaces. The at-risk workforce comprises about 2 million construction workers who drill, cut, crush and/or grind silica-containing materials such as concrete and stone. OSHA claims the final rule will save more than 640 lives and prevent more than 900 new cases of silicosis each year though some industry groups, including NRCA, dispute these projections.

Silica is the chemical compound silicon dioxide (SiO2). Sand, a key component in many building products such as mortar, clay and concrete tiles, pavers and brick, mainly is composed of silica in the form of quartz. Hazards develop when materials containing silica are cut, drilled and/or ground in a way that produces RCS. This most often is done with powered saws or grinders with diamond blades or silicon carbide-cut wheels that produce inhalable airborne particles.