A small town of 700 in North Dakota has closed one of its two ballparks dues to risks associated with its gravel.  Residents of Killdeer are skeptical of the park's closing, but Steve Way of the Environmental Protection Agency says its best to be wary.  The gravel in the ballpark is made of erionite, a substance mined close to Killdeer.  Though erionite is not regulated by the EPA, preliminary tests indicate that the material causes cancer in rats.

In Turkey, a variety of erionite has been linked to mesothelioma.  However erionite there is sodium-based, and in Killdeer is it calcium-based.  Studies are being conducted to evaluate the risks of Killdeer's erionite.  Find the full article here.