Question: What OSHA Standards cover silica exposure and hydraulic fracturing?

Answer: The OSHA Permissible Exposure Limit (PEL) for silica is outlined in the OSHA Air Contaminants standard (29 CFR 1910.1000 Table Z-3.) The PEL for quartz, the common form of crystalline silica found in sand, is an 8-hour time-weighted average exposure to respirable dust calculated from the following formula: PEL = 10 / [(% Silica) + 2] The PEL is approximately equal to 0.1 mg/m3 for pure quartz silica. If other forms of crystalline silica are present, the PEL calculation must be modified per Table Z-3. Additionally, OSHA Directive CPL 03-00-007 National Emphasis Program – Crystalline Silica, has detailed information on silica hazards, guidelines for air sampling, guidance on calculating PELs for dust containing silica, and other compliance information. Several OSHA standards and directives also cover operations that may expose workers to silica, including: Hazard Communication (29 CFR 1910.1200) Respiratory Protection (29 CFR 1910.134) In addition to silica hazards, workers may be exposed to other worksite health hazards that can include exposure to diesel particulate and exhaust gases from equipment, high or low temperature extremes, high noise levels, and overexertion leading to sprains and strains. In addition, fatigue may be a concern due to long working hours. See OSHA's Oil and Gas Well Drilling and Servicing eTool website for more information about the standards that cover safety and health hazards at oil and gas extraction sites.