Rochester Post-Bulletin coverage of Jan 18th Frac Sand Summit in Winona

"WINONA — When it comes to exposure to silica sand, the tiniest particles are the biggest threat to human health, two experts said Saturday during the Silica Sand Summit in Winona.

Professors from the University of Wisconsin — Eau Claire and West Virginia University said that while silica sand is helping the country become more energy independent, it's also a threat to the health of people working with it and living near it."

http://www.postbulletin.com/business/experts-ultrafine-particles-are-biggest-silica-threat/article_b56264ee-da4a-5185-8bbe-509668447e54.html