"The first time Bill Ferullo saw the white plumes drifting from a natural gas fracking site, he got out of his car to take pictures. 'I didn't know what it was,' he recalled. 'But two minutes later my chest was burning. It burned all night.'"
"In the two years since, Ferullo has watched similar dust clouds travel as far as a mile, he estimates, from gas drilling operations around his home in Bradford County, Pa. He has also since learned what hazards they may carry. One component in particular concerns Ferullo, as well as other residents and environmental health experts: silica sand, a long-known cause of debilitating and deadly diseases such as silicosis and lung cancer.
'At frack sites, silica gets into the air and you get these huge plumes of dust that can be breathed in by workers and anybody nearby, downwind,' said Miriam Rotkin-Ellman, scientist at the Natural Resources Defense Council."