Get the Facts About Frac Sand:
Understanding Sandstone Mining and Processing
Progressive Rail Incorporated & Wisconsin Northern Railroad | February 9, 2012
Silica Sand & Air Quality
Michael J. McCoy, MS, CIH, CHMM
GZA GeoEnvironmental, Inc.
Quartz is the most common silica crystal and the second most common mineral on the earth’s surface.
Sandstone is comprised of quartz silica sand and is present across the majority of Wisconsin and is present on all of Wisconsin’s beaches. Silica sandstone mining has been ongoing in Wisconsin since the 1800s, and many western Wisconsin companies mine and process sandstone, which consists primarily of crystalline silica.
Only recently has the public become aware that one of the numerous uses for the silica sand mined in Wisconsin is for hydro-fracturing of oil and gas reservoirs; a practice that is as old as the oil and gas industry. When used in the oil and gas industry, the silica sand is referred to as “frac sand”. When used elsewhere silica sand is referred to as “glass sand”, “filter sand”, “texture sand”, “traction sand”, “foundry sand”, “shingle sand”, “play sand”, etc. This specialty industrial sand is also commonly and extensively used in numerous household products, such as cleansers, paint, clays, talcum powders, cat litter, cosmetics, and is a natural component of the soil used every day for gardening and farming. It is present on the beaches in which we recreate and is also present in childrens’ sandboxes. Silica sand is present as a vehicle travels down a gravel road on a dry summer day.
Recently the sand mining industry has been targeted with a barrage of opinions regarding alleged negative impacts of silica sand mining on ambient air quality. Let’s take a moment to look at some facts.
In August 2011, the Wisconsin Department of Natural Resources (WDNR) released a silica sand study in accordance with the Wisconsin Air Toxics rule (Ch. NR 445, Wis. Adm. Code).(1) The WDNR’s silica sand study provided some remarkable facts:
• “Sources of crystalline silica are ubiquitous and include paved and unpaved roads, wind-blownsoil and agricultural activities (e.g., tilling and harvesting.)”
• “Controls for crystalline silica are the same controls typically used for particulate matter (PM).”
• “Wisconsin has regulated PM for 40 years. The controls for PM are the same controls for crystalline silica. This means that for those crystalline silica sources where PM is controlled, crystalline silica emissions are also reduced.”
• “A recurring theme from the literature review and survey is that very little conclusive information exists regarding sources, controls or levels of silica present in ambient air.” (1)
Even more recently, the WDNR denied a citizen group’s request that the WDNR specifically regulate airborne crystalline silica emissions. The WDNR replied, “Because silica emissions are a component of particulate matter emissions, existing regulations that govern fine particulate matter can be used to control these emissions.” Wisconsin’s environmental regulatory framework evaluates crystalline silica as part of the total particulate emissions, of which mining companies much comply with numerous requirements of its WDNR air permits.
The United States Environmental Protection Agency (USEPA) also provides us with some interesting facts about ambient crystalline silica emissions. The USEPA determined that mining contributed only 1% of the PM emissions to the ambient air.(2) The USEPA using its own data on PM emissions collected from its sampling network throughout the United States, estimated the percentage of crystalline silica airborne from various sources as shown to the right:(2)
As an environmental health professional, I have provided the preceding facts about sandstone mining and processing and its impacts on air quality. It is my hope that citizens of Chippewa Valley will take a few moments to understand all there is to know about the true environmental, health and economic impacts of sandstone mining in Western Wisconsin. Then decide for yourself. When you see a report, flyer or bulletin, ask yourself is that a fact or the opinion of an anti-mining activist.
Mr. McCoy is an environmental health consultant, board-certified industrial hygienist and toxicologist. As part of his consulting practice he evaluates and controls exposure to crystalline silica amongst other occupational and environmental agents in order to protect worker and public health.
1. Wisconsin Department of Natural Resources, Report to the Natural Resources Board: Silica Study. August 2011. AM-407, 2011. http://dnr.wi.gov/air/pdf/finalsilicareport.pdf
2. United States Environmental Protection Agency (USEPA). 1996 November. Ambient levels and non-cancer health effects of inhaled crystalline and amorphous silica; health issue assessment (EPA/600/R095/115). Research Triangle Park, NC: National Center for Environmental assessment, Office of Research and Development, USEPA. http://www.epa.gov/NCEA/pdfs/0604.pdf