OSHA Alert On Silica Exposure During Fracing Operations

The Occupational Safety & Health Administration (OSHA) has issued a hazard alert regarding potential overexposure to silica as a health hazard to workers conducting hydraulic fracturing operations. As noted in the alert, respirable silica is a hazard common to many industries and industrial processes.

Since large quantities of silica sand are used during hydraulic fracturing, NIOSH began a cooperative effort in January 2010 to collect data regarding silica exposure at hydraulic fracturing operations. Working in cooperation with oil and gas industry partners to sample the air at 11 sites in five states where hydraulic fracturing operations were taking place, NIOSH identified seven primary sources of silica dust exposure during fracturing operations:

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

It also found that workers downwind of sand mover and blender operations, especially during hot loading, had the highest silica exposures. Transporting, moving, and refilling silica sand into and through sand movers as well as along transfer belts and into blender hoppers, can also release dust into the air containing up to 99% silica that workers breathe.

The alert describes how a combination of engineering controls, work practices, protective equipment and product substitution, where feasible, along with worker training, can protect workers who are exposed to silica. According to OSHA, engineering controls and work practices provide the best protection for workers.


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