That fine, breathable silica particles can threaten workers' health has been known for a long time. And we know that the silica used in hydraulic fracturing of tight oil and gas formations can also endanger workers — because the National Institute of Occupational Safety and Health (NIOSH) has done studies showing this.
But a Freedom of Information Act request seeking to know the sites where workers had been endangered has met with no response, independent journalist and SEJ member Elizabeth Grossman reports. Grossman FOIA'd specifics behind studies done in 2010 and 2011 by NIOSH and the Centers for Disease Prevention and Control (CDC) — but has yet to get any information 13 months after she filed the request in June 2012. She was writing about fracking sand for The Pump Handle, a public health blog.
NIOSH and CDC studied eleven fracking sites in five states, finding that unsafe levels of breathable silica were common. The results caused NIOSH and the Occupational Safety and Health Administration (OSHA) to issue a "Hazard Alert" in June 2012. Sources have suggested to Grossman that disclosure would discourage companies from cooperating with research to assess the threats of occupational exposure.
- "Frac Sand Exposure Study FOIA: 13 Months and Still No Response from CDC,"  The Pump Handle, July 10, 2013, by Elizabeth Grossman.