Minnesota Dept of Health on frac sand mining health hazards

The Minnesota Department of Health just published information about the health risks associated with frac sand mining.  Click HERE to download the PDF.

Frac Sand Mining in Minnesota

Hydraulic fracturing, or fracking, is used to increase the flow in an oil and gas well by using hydraulic pressure to force cracks in bedrock. A fluid containing frac sand is forced through the rock and the sand helps to keep the enlarged cracks open so the oil or gas can flow more quickly to the well. This type of oil and gas extraction is not being done in Minnesota, but because of Minnesota’s geologic history, the high quality sand used for fracking is plentiful in parts of the state and easily available for mining.

How are people exposed to frac sand and is there a health concern?

Crystalline silica is a substance of concern for human health. Dust sized silica particles, invisible to the naked eye, are generated during the mining process and can be breathed into the body where they reach deep into the lungs and can then pass from the lungs to other organs in the body through the blood stream.

People who work in the fracking or mining industry can be exposed to crystalline silica during the course of their work. These exposures can range from low to high concentrations.

People living downwind of frac sand mining, processing or hauling operations could be exposed to low concentrations of airborne crystalline silica.

What are the possible health concerns from exposure to crystalline silica?

Diseases associated with crystalline silica exposure include:

  • Diseases of the lungs including silicosis, emphysema, chronic obstructive pulmonary disease, tuberculosis, and lung cancer.
  • Immune system diseases

Disease risk is related to both the levels and duration of crystalline silica exposure. The onset of disease may occur long after the exposure has stopped.

At high concentrations in the air: The effect of crystalline silica in humans has been well studied. The US Occupational Safety and Health Administration have set a permissible exposure limit for crystalline silica for occupational exposures. The National Institute for Occupational Safety and Health also has a recommended exposure limit. There is research which suggests the current occupational limits may not be protective enough.

At lower concentrations in the air: We do not currently know what impacts silica has at lower concentrations such as those typically found in ambient air. This is an area of on-going research.

What are other possible health concerns from frac sand mining?

Because frac sand mining operations operate for many hours a day, there may be an increase in health and nuisance issues including:

  • truck traffic, dust, noise, risk of accidents and increased levels of engine exhaust.
  • emissions from the mining process (blasting, digging equipment and fixed machinery) can result in more dust and chemicals being released into the air.

Health Impact Assessment (HIA) is a process that could lead to a more complete evaluation of all of the risks associated with the frac sand mining process. For more information about Health Impact Assessments, see http://www.health.state.mn.us/divs/hia/

Will frac sand mining or processing affect the drinking water?

  • Any mine may create a pathway for chemicals and/or bacteria to more easily reach the groundwater.
  • The risks to drinking water depend on how close the mining operations are to the
    water table, the use of heavy equipment, leaks and spills of fuel, engine oil or
    other chemicals, and runoff from contaminant sources or illegally dumped waste in the mine.
  • Groundwater near frac sand mines may become slightly more acidic (lower in pH). This may cause minerals (like iron and manganese) to more easily dissolve into the water. These minerals can cause water to have unpleasant taste and odor and may cause staining. MDH recommends that pH be included in the water monitoring list for groundwater near frac sand mining operations.
  • Some frac sand mines use products called flocculants to remove silt and clay in the sand washing process. These products are generally considered to be environmentally safe; however, they often contain low concentrations of chemicals (acrylamide and DADMAC) which are of potential concern. MDH recommends monitoring of the groundwater at facilities where these chemicals are to be used to ensure safe drinking water levels are not exceeded.

Will frac sand mining affect well water?

Mining can remove large volumes of groundwater and has the potential to impact nearby wells. Impacts could include the lowering of water levels, possibly even causing a nearby well to go dry.

The Minnesota DNR reviews large water removal activities to ensure that groundwater use will not harm wells in the area.

MDH evaluates whether there are any potential risks to community water supply wells.

MDH recommends a number of actions to prevent or reduce the potential for pollutants to enter the groundwater and water quality monitoring to protect nearby drinking water wells. For more information, see “Wellhead Protection Issues Related to Mining Activities” at http://www.health.state.mn.us/divs/eh/water/swp/mining.pdf

Contact with questions or for more information:

MDH – Site Assessment and Consultation Unit
Phone: 651-201-4897 or toll-free 1-800-657-3908 and press “4” to leave a message Email: health.hazard@state.mn.us or visit: http://www.health.state.mn.us/divs/eh/hazardous/index.html

September 2012 Frac Sand Mining in Minnesota – English

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