Silica Exposure During Fracking-March 2013

Monthly Round Up of Important Ideas and Standards in
Industrial Hygiene and Safety 

March 2013

IN THIS ISSUE: Silica Exposure During Fracking

Hydraulic fracturing (“fracking”) is a significant source of silica exposure for workers. Long a part of oil production, the use of fracking has increased significantly in recent years. New horizontal drilling and multi-stage fracking have improved the ability to capture oil and natural gas.  Silica, a basic component of soil, sand, granite, and many other minerals, is a lung carcinogen that becomes respirable when workers chip, cut, drill, or grind objects that contain crystalline silica.  Silica dust enters the lungs and causes scar tissue to form, thus reducing the lungs’ ability to take in oxygen.  The National Institute of Safety and Health (NIOSH) studies fracking and has recognized silica as a significant hazard.

Regulation of silica exposure by the government has been lagging. OSHA has an outdated Permissible Exposure Limit, and efforts to reduce the limits have been stuck in Congress. However, the American Conference of Governmental Industrial Hygienists (ACGIH) has adopted the 8-hour time weighted average concentration for silica quartz and silica cristobalite of 0.025 milligrams/cubic meter that is well below OSHA’s limits. Industries hygienists rely on ACGIH methods to provide the best protection.

NIOSH is currently developing best practices to protect workers who conduct hydraulic fracturing.  During fracking, large volumes of water and sand under high pressure are used to break up well formations. Sand is transferred from sand bins, mixed with water and chemicals, and injected by a series of pumper trucks. Along the way open belts and conveyors generate dust. OSHA and NIOSH have identified seven areas of concern for workers during fracking: 

  1. Dust ejected from thief hatches (access ports) on top of the sand movers during refilling operations while the machines are running (hot loading).
  2. Dust ejected and pulsed through open side fill ports on the sand movers during refilling operations.
  3. Dust generated by on-site vehicle traffic.
  4. Dust released from the transfer belt under the sand movers.
  5. Dust created as sand drops into, or is agitated in, the blender hopper and on transfer belts.
  6. Dust released from operations of transfer belts between the sand mover and the blender.
  7. Dust released from the top of the end of the sand transfer belt (dragon’s tail) on sand movers.

Go to for further discussion and best practices on this issue. For more information on this topic and to discuss your company’s safety and industrial hygiene needs call OccuSafe at (214) 662-6005 or visit us at

OccuSafe Environmental and Safety, Inc. provides skills and expertise to recognize, evaluate and control hazards and injuries in the areas of industrial hygiene, occupational safety and health.   OccuSafe services companies of all sizes in a range of industries.

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