LEGALLY SPEAKING New OSHA Standards on Respirable Silica to Take Effect Health Risks Defining Respirable Crystalline Silica Crystalline silica is a common mineral found in construction materials, including sand, soil, abrasives, concrete and filter aids. Crystalline silica only becomes hazardous when it becomes airborne (known as respirable crystalline silica). Respirable crystalline silica is created when workers drill, chip, grind or mix minerals containing crystalline silica, thus releasing tiny particles of silica into the air. In the construction industry, the most severe exposure occurs during abrasive sandblasting, jackham- mering, drilling, saw cutting, concrete/grout mixing and grinding materials. For deep foundation contractors, this respirable silica can be produced when drilling rock, batching concrete or grout on site, or chip- ping or core drilling drilled shaft foundations. The United States Occupational Safety and Health Administration (OSHA) estimates that silica dust exposure kills over 600 workers a year in the U.S. alone, and places many more at risk for developing lung cancer, respiratory illnesses, such as chronic obstructive pulmonary disease, kidney disease and silicosis. The World Health Organization’s (WHO’s) International Agency for Research on Cancer and the National Institutes of Health’s (NIH’s) National Toxicology Program have performed numerous studies on crystalline silica and, because of these studies, have designated crystalline silica as a known human carcinogen. The National Cancer Institute’s (NCI’s) website contains the following information about respirable crystalline silica: “Exposure of workers to Jeanne Harrison, Associate and Brian Wood, Attorney Of Counsel, Smith, Currie and Hancock respirable crystalline silica is associated with elevated rates of lung cancer. The strongest link between human lung cancer and exposure to respirable crystalline silica has been seen in studies of quarry and granite workers and workers involved in ceramic, pottery, refractory brick and certain earth industries.” In total, OSHA estimates that approxi- mately 2.3 million workers are exposed to respirable crystalline silica in the work- place, including approximately 2 million construction workers who drill, chip, grind, crush or cut silica containing material, and 300,000 workers in general industry operations such as brick manufacturing and fracking. New Silica Standards On March 25, 2016, OSHA published new standards regulating workplace exposure to respirable crystalline silica. Under the new standards, which become effective for the construction industry on June 23, 2017, employers are responsible for the following: • Limiting employee exposure to respirable crystalline silica. Under the new regulations, the personal exposure limit (PEL) for respirable crystalline silica is reduced from 250 µg/cu m to 50 µg/cu m, (191 µg/cu yd to 38 µg/cu yd), as an eight-hour time-weighted average (TWA). If the PEL exceeds 50 µg/cu m (38 µg/cu yd), then engineering con- trols (detailed in the regulation) must be utilized. By way of comparison, the DEEP FOUNDATIONS • MAR/APR 2017 • 113
