The National Institute for Occupational Safety and Health (NIOSH) in the US has identified exposure to airborne silica as a health hazard to workers conducting some hydraulic fracturing (or ‘fracking’) operations during recent field studies.
Fracking involves pumping large volumes of water and sand into a well at high pressure to fracture shale and and gain access to natural gas.
NIOSH’s field studies show that workers may be exposed to dust with high levels of respirable crystalline silica during hydraulic fracturing.
NIOSH collected 116 air samples at 11 different hydraulic fracturing sites in five different states to evaluate worker exposure to crystalline silica. At each of the 11 sites, full-shift personal-breathing-zone (PBZ) exposures to respirable crystalline silica consistently exceeded relevant occupational health criteria.
Inhalation of fine dusts of respirable crystalline silica can cause silicosis. Silicosis is an incurable but preventable lung disease.
A NIOSH blog post about the study notes,
To date, most of the attention on the safety and health implications of hydraulic fracturing has been related to impacts on the environment, primarily the potential for ground water contamination by hydraulic fracturing fluids. Although worker safety hazards in the oil and gas extraction industry are well known, there is very little data regarding occupational health hazards during hydraulic fracturing operations; for example, whether workers are exposed to toxic chemicals at hazardous concentrations. To investigate potential worker health hazards in this rapidly expanding industry and address the existing lack of information on occupational dust and chemical exposures associated with hydraulic fracturing, NIOSH initiated the NIOSH Field Effort to Assess Chemical Exposures in Oil and Gas Extraction Workers . Initial hazard assessments identified exposure to crystalline silica during hydraulic fracturing as the most significant known health hazard to workers and this has been the focus of the NIOSH study to date.
The NIOSH report makes a variety of recommendations for industry to improve worker safety. These range from more traning for workers to using a less hazardous non-silica proppant (e.g., ceramic) where feasible.