On September 23, The U.S. Department of Labor’s Occupational Safety and Health Administration began enforcing updated regulations regarding workers’ exposure to respirable silica dust.
The permissible exposure limit has been lowered to 50 micrograms per cubic meter of air, averaged over an 8-hour shift. Acceptable levels in the past were either 100 micrograms or 250 micrograms, depending on the industry.
Crystalline silica is a natural mineral found in sand, concrete, mortar, brick and stone. When these materials are cut or crushed, crystalline silica dust is released into the air and inhaled into workers’ lungs. This exposure can lead to a host of medical problems, including lung cancer, kidney disease and chronic bronchitis.
The previous exposure limits were established in 1971, but studies have shown that those levels were still dangerous.
