ELKADER — Airborne silica particles resulting from the proposed expansion of the Pattison sand mine pose a “low risk to human health,” University of Iowa professor Patrick O’Shaughnessy said Thursday night at a meeting of the committee studying potential impacts of the expansion.
O’Shaughnessy, who specializes in occupational and environmental health and safety, spoke at a packed meeting of the Mine Reserve Expansion Study Committee, a five-member panel established by the Board of Supervisors to determine the environmental, economic and aesthetic impacts of Pattison’s proposed expansion.
Several Clayton County landowners have requested that 746 acres near Pattison’s mine along the Mississippi River be rezoned from agricultural to heavy industry to facilitate underground mining of the silica sand used in the hydraulic fracturing process of extracting oil and natural gas.
O’Shaughnessy said silica crystals small enough to be inhaled deep into the lungs present the greatest airborne health threat associated with the mining of frack sand.
Occupational exposure to respirable crystalline silica is associated with the development of silicosis, lung cancer, pulmonary tuberculosis and airway diseases, according to the National Institute for Occupational Safety and Health.
Only particles smaller than 10 microns (which are invisible to the human eye) can penetrate deeply enough into the lungs to cause pulmonary ailments, O’Shaughnessy said.
In recent studies near Wisconsin sand mines, O’Shaughnessy and colleagues detected respirable crystalline silica but at levels well below standards and guidelines set by the Environmental Protection Agency and the Occupational Safety and Health Administration.
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They concluded that “health risks from inhaling particles from sand mining are likely to be low.”
O’Shaughnessy advised the committee that ventilation shafts from the underground mine should be set back a safe distance from nearby homes.
“A half mile would be a good conservative distance,” he said.
The committee is charged with developing recommendations to the Planning and Zoning Commission, which will rule on the zoning change petition.