"Learn more about workplace solutions for controlling exposures to Respirable Crystalline Silica in construction and hydraulic fracturing. Save lives and prevent new cases of silicosis, a severe lung disease. Understand the occupational exposure limits to keep workers safe from breathing hazardous silica dust.Approximately 2.3 million workers are exposed to respirable crystalline silica (RCS) in the workplace, including 2 million workers in construction and 300,000 workers in general industry, maritime and hydraulic fracturing. As early as 1974, NIOSH researchers had proposed a recommended exposure limit (REL) of 50 micrograms per cubic meter (50 µg/m3) for inhalation of dust containing RCS, as a time-weighted average for up to a 10-hour workday as part of a 40-hour workweek. NIOSH research into engineering control methods to reduce RCS exposures in the workplace are ongoing, helping employers to safeguard the health of their employees..."