BOX 6. FOCUS ON SILICA DUST AND SHALE DEVELOPMENT OPERATIONS
As silica sand is commonly used as a proppant during the hydraulic fracturing of shale deposits – requiring up to 10,000 tons of sand for the fracturing and re-fracturing of a single well 1 – the mining of silica sand for shale development operations has increased dramatically in recent years. Much of this silica is mined and processed in western Wisconsin, where the number of active silica sand facilities increased from 7 in 2010 to 85 in 2015. Illinois, Texas, and Minnesota also have significant silica sand facilities. 2, 3 This boom in the production of silica sand has led to concerns about increased exposures for workers and residents near sand mining and shale development operations.
What are the health concerns with silica dust?
Silica dust, officially known as respirable crystalline silica, is composed of microscopic particles about 100 times smaller than ordinary beach or playground sand. It has long been known that silica dust creates health risks for employees working in certain industries, including during the mining of this naturally occurring mineral. Health risks from exposure include respiratory problems like bronchitis and asthma; chronic obstructive pulmonary disease (COPD); silicosis, which is a permanent scarring and chronic inflammation of lung tissue; lung cancer; and kidney disease. Exposure has also been associated with some autoimmune disorders like rheumatoid arthritis and lupus, as well as with heart disease. 4
What is workers’ exposure to silica?
In June 2012, the Occupational Safety and Health Administration (OSHA) disseminated a hazard alert for workers in the oil and gas industry, based on air samples taken at shale development sites. 5, 6 Many samples showed potential exposure levels above those considered safe, and some sites had levels ten times or more above the current permissible exposure limit (PEL). In September 2013, based on new research and analysis, the OSHA proposed more stringent standards for silica exposure. 7 If adopted, the new regulations would limit worker exposure to a PEL of 50 micrograms of respirable crystalline silica per cubic meter of air, averaged over an 8-hour workday. In addition, OSHA suggested provisions for measuring exposures and for reducing or mitigating risk. The National Industrial Sand Association (NISA), an industry group, has also developed a program for eliminating the adverse health effects of inhaled respirable silica through a program of careful monitoring and management of exposures. 8
What is the community’s exposure to silica?
The risks to communities in proximity to sand mining and shale development operations are currently not well understood. Community members near sand mining sites have voiced concerns about the local air quality and potential water contamination due to both the silica dust around the sites and the chemicals used in processing the sand. Silica dust could also affect residents living near rail lines transporting silica sand. In addition, some have pointed out that agricultural soils around mining sites may be compromised as the dust blows across farmland. 9
To better understand the risks to communities near silica sand mines, in September 2013 the National Institutes of Health (NIH) approved a grant to the University of Iowa to study the impact of mines on respirable crystalline silica levels in nearby communities. 10 The researchers plan to take air samples from nearby homes, as well as to assess silica sand migration during rail transport.
What can be done to address health concerns?
Operators: The OSHA-NIOSH hazard alert and the NISA program contain the following recommendations that companies should undertake to protect workers:
Groups concerned about the effects on communities have also made suggestions for improving public safety, such as installing air monitors every 1,000 feet around the perimeter of sand mining facilities and using closed-car rail transport when possible. 12
- Zahra Hirji, “’Frac Sand’ Mining Boom: Health Hazard Feared,” Inside Climate News, November 5, 2013. ↩
- Zahra Hirji, “‘Frac Sand’ Mining Boom.” ↩
- Wisconsin Department of Natural Resources, “Locations of Industrial Sand Mines and Processing Plants in Wisconsin,” last revised September 8, 2015 ↩
- Centers for Disease Control and Prevention, “Workplace Safety and Health Tips: Silica” (July 2013). ↩
- Occupational Safety & Health Administration (OSHA), “OSHA-NIOSH Hazard Alert: Worker Exposure to Silica during Hydraulic Fracturing,” accessed December 6, 2014. ↩
- Eric Esswein, Max Kiefer, John Snawder, and Michael Breitenstein, “Worker Exposure to Crystalline Silica During Hydraulic Fracturing,” NIOSH Science Blog (May 23, 2012). ↩
- OSHA, “OSHA’s Proposed Crystalline Silica Rule: Overview” (September 2013). ↩
- National Industrial Sand Association, “Occupational Health Program for Exposure to Crystalline Silica in the Industrial Sand Industry” (2011). ↩
- Wisconsin League of Conservation Voters, “Frac Sand Mining,” accessed December 6, 2014. ↩
- University of Iowa, Environmental Health Sciences Research Center, “Exposure Assessment and Outreach to Engage the Public on Health Issues from Frac Sand Mining,” accessed December 6, 2014 ↩
- OSHA, “OSHA-NIOSH Hazard Alert: Worker Exposure to Silica.” ↩
- Wayne Feyereisn, “Potential-Public-Health-Risks-of-Silica-Sand-Mining-and-Processing,” slide show, available as a PowerPoint presentation through The Sand Point Times, accessed December 7, 2014. ↩