The Occupational Safety and Health Administration (OSHA) has issued a final rule addressing protections for workers exposed to respirable silica dust. The final rule, Occupational Exposure to Respirable Crystalline Silica, published in the Federal Register on March 25, and an OSHA Fact Sheet, a summary document of the rule, are posted on the OSHA website.
OSHA's premise is that "employees exposed to respirable crystalline silica at the previous permissible exposure limits face a significant risk of material impairment to their health". The agency indicates that "workers exposed to respirable crystalline silica are at increased risk of developing silicosis and other non-malignant respiratory diseases, lung cancer, and kidney disease".
The final rule includes standards for general industry and maritime, as well as standards for construction. Crystalline silica is a common mineral found in materials that we see every day in roads, buildings, and sidewalks. It is a common component of sand, stone, rock, concrete, brick, block, and mortar. The greatest exposure is expected from operations involving "cutting, sawing, drilling, and crushing of concrete, brick, block, rock, and stone products (such as construction tasks), and operations using sand products (such as in glass manufacturing, foundries, sand blasting, and hydraulic fracturing)", indicated in the OSHA Fact Sheet. OSHA identifies the following industries as those most affected: construction, glass manufacturing, pottery products, structural clay products, concrete products, foundaries, dental laboratories, paintings and coatings, jewelry production, refractory products, ready-mix concrete, cut stone and stone products, abrasive blasting in maritime, construction, and general industry, refractory furnace installation and repair, railroad transportation, and oil and gas.
Workers in the LBM sector may have exposure resulting from gravel dust in yards and construction sites; however, the permissible exposure limit set by the final rule is 50 micrograms of respirable crystalline silica per cubic meter of air (50 μg/m3) as an 8-hour weighted average. Where applicable, the rule establishes requirements for exposure assessment, methods for controlling exposure, respirable protection, medical surveillance, hazard communication, and recordkeeping. The rule relies on the hierarchy of controls whereby the employer subject to the rule will be expected to employe engineering controls and workplace practices before relying on respiratory protection through the use of personal protective equipment.
As part of the final rule, OSHA made a determination to exclude exposures in general industry and maritime where the employer has objective data demonstrating that employee exposure to respirable crystalline silica will remain below 25 μg/m3 as an 8-hour TWA under any foreseeable conditions. OSHA is also excluding exposures in construction where employee exposure to respirable crystalline silica will remain below 25 μg/m3 as an 8-hour TWA under any foreseeable conditions.