| Material, Task, Etc. | Year of Study | Title | Summary |
|---|---|---|---|
| Sand Transfer & Loading | 2018 | Dust Suppression Hopper reduces dust liberation during bulk loading: Two case studies | Sand that is being transferred and loaded can release dust into the work environment. For bulk loading of sand into trucks or trains, NIOSH evaluated a Dust Suppression Hopper (DSH) at two industrial sand processing plants. Results showed that the DSH reduced airborne respirable dust levels by 39–88%, depending on the size of the sand being loaded. |
| Sand movers | 2017 | Evaluation of an improved prototype mini-baghouse to control the release of respirable crystalline silica from sand movers | This article described the results of an evaluation of the 3rd generation NIOSH Mini-Baghouse Retrofit Assembly (NMBRA) at a sand mine in Arkansas in 2015. For this study, 168 area air samples were collected at 12 locations on and around a sand mover with and without the NMBRA installed. Analytical results for respirable dust and respirable crystalline silica (RCS) indicated that the use of the NMBRA effectively reduced concentrations of both respirable dust and RCS downwind of the thief hatches. Reductions of airborne respirable dust were estimated at 99+%; reductions in airborne RCS ranged from 98–99%. Use of an improved filter fabric and a larger area of filter cloth led to substantial improvements in filtration and pressures during these trials, as compared to the 2nd generation NMBRA. |
| Sand movers | 2016 | In-Depth Survey Report: Field Evaluation of the NIOSH Mini-Baghouse Assembly Generation 3 for Control of Silica Dust on Sand Movers | This NIOSH report provided detailed results and the completed dataset of the evaluation of the 3 rd generation NIOSH mini-baghouse retrofit assembly (NMBRA) that occurred at Southwestern Energy Sand Company in North Little Rock, Arkansas in 2015. Results indicated that the mini-baghouse retrofit assembly effectively reduced both respirable dust and respirable crystalline silica (RCS) downwind of the thief hatches. Measurements of the static pressure inside the bags remained low throughout the filling of the sand mover, avoiding the need to suspend sand transfer and manually shake filter bags. Analysis of a bulk sample of the dust collected by the baghouse assembly during this trial showed the presence of silicon, silica monoxide and the silica dioxide radicals which are indicators of freshly fractured quartz, a particularly hazardous form of RCS. Design enhancements were proposed to provide weather resistance and ease of clamping for the mini-baghouse. |
| Sand movers | 2016 | The development and testing of a prototype mini-baghouse to control the release of respirable crystalline silica from sand movers | This article described the results of a trial of the 2nd generation NIOSH mini-baghouse at a sand mine in Arkansas in 2013. During the trial, area air samples were collected at 12 locations on and around a sand mover with and without the mini-baghouse control installed. Results for respirable dust and RCS indicated the use of the mini-baghouse effectively reduced both respirable dust and respirable crystalline silica (RCS) downwind of the thief hatches. Reductions of airborne respirable dust ranged from 85–98%; reductions in airborne RCS ranged from 79–99%. The study noted that future design enhancements and trials to determine additional respirable dust and RCS concentration reductions were planned. |
| Fracking | 2013 | Occupational Exposures to Respirable Crystalline Silica During Hydraulic Fracturing | This report described a previously uncharacterized occupational health hazard: work crew exposures to respirable crystalline silica during hydraulic fracturing. Researchers collected 111 personal breathing zone samples at 11 sites in five states to evaluate worker exposures to respirable crystalline silica during hydraulic fracturing. At each of the 11 sites, full-shift samples has exceeded occupational health standards, in some cases, by 10 or more times. Based on these evaluations, an occupational health hazard was determined to exist for workplace exposures to crystalline silica. Seven points of dust generation were identified, including sand handling machinery and dust generated from the work site itself. Recommendations to control exposures included product substitution (when feasible), engineering controls or modifications to sand handling machinery, administrative controls, and the use of personal protective equipment. |
| Fracking | 2012 | Worker Exposure to Crystalline Silica During Hydraulic Fracturing | This NIOSH Science Blog announced a field research effort focused on fracking. NIOSH initiated the NIOSH Field Effort to Assess Chemical Exposures in Oil and Gas Extraction Workers to investigate potential worker health hazards in this rapidly expanding industry and to address the existing lack of information on occupational dust and chemical exposures associated with hydraulic fracturing. Initial hazard assessments identified exposure to crystalline silica during hydraulic fracturing as the most significant known health hazard to workers. |