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Occupational exposures to silica associated with hydraulic fracturing: National Institute for Occupational Safety and Health (NIOSH) field operations.

Authors
Weston-A
Source
Environ Mol Mutagen 2013 Sep; 54(S1):S14
Link
http://dx.doi.org/10.1002/em.21814
NIOSHTIC No.
20043153
Abstract
Throughout the Institute's history, NIOSH has engaged in occupational safety and health research in extraction industries (e.g., mining), but only since 2005 has NIOSH focused on upstream oil and gas extraction. During initial site visits at oil and gas wells, it was observed that notable amounts of silica-containing proppant, or frac-sand, are used during hydraulic fracturing operations. This observation led to research of workers' exposures to silica at 11 sites in 5 states. In 2010-2011, full shift (typically 12 hours) personal breathing zone samples for respirable silica were collected from workers in 15 job categories who participated voluntarily. Sample analyses were performed by an accredited laboratory, using validated NIOSH methods. Time-weighted average concentrations of respirable crystalline silica were calculated for comparisons with the Occupational Safety and Health Administration permissible exposure limit (PEL), the NIOSH recommended exposure limit (REL), and the American Conference of Governmental Industrial Hygienists threshold limit value (TLV). Of a total of 111 individual samples collected, 93 (83.8%) exceeded the TLV, 76 (68.5%) exceeded the REL, and 57 (51.4%) exceeded a calculated PEL, in some cases by more than 10-fold the PEL, REL, or TLV. By job category, sand mover and transport belt operators had the highest exposures. Risks for silica exposures are significant during hydraulic fracturing due to the quantity of sand used and the way it is handled. Seven primary points of dust generation were identified in this study along with recommendations for controls.
Keywords
Mining-industry; Oils; Oil-industry; Oil-refineries; Gases; Gas-industry; Silicates; Silica-dusts; Workers; Exposure-levels; Risk-factors; Breathing-zone; Sampling; Humans; Men; Analytical-processes; Statistical-analysis; Dusts; Dust-particles
CODEN
EMMUEG
CAS No.
7631-86-9; 14808-60-7; 14808-60-7
Publication Date
20130901
Document Type
Abstract
Fiscal Year
2013
Identifying No.
M102013
ISSN
0893-6692
NIOSH Division
DRDS
Source Name
Environmental and Molecular Mutagenesis
State
WV
Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division