Labor groups are working to get more attention paid to the risks of silica exposure in hydraulic fracturing or fracking in the shale gas industry.
The labor group has been writing letters to federal agencies, pointing out that a two-year federal assessment found that among workers exposed, 79 percent of silica samples exceeded recommended federal exposure limits.
The letters are signed by the AFL-CIO, plus the United Mine Workers of America and the United Steelworkers.
Chesapeake Energy Corp,the Oklahoma-based firm is the No. 1 driller in Ohio.
Rig Count Interactive Map by Baker Hughes, an energy services company.
Shale Sheet Fracking, a Youngstown Vindicator blog.
The Ohio Environmental Council, a statewide eco-group based in Columbus.
Earthjustice, a national eco-group.
People's Oil and Gas Collaborative-Ohio, a grass-roots group in Northeast Ohio.
Concerned Citizens of Medina County, a grass-roots group.
No Frack Ohio, a Columbus-based grass-roots group.
Fracking: Gas Drilling's Environmental Threat by ProPublica, an online journalism site.
Pipeline, blog from Pittsburgh Post-Gazette on Marcellus shale drilling.
Allegheny Front, environmental public radio for Western Pennsylvania.