Researchers working for the National Institute of Occupational Safety and Health published a study with disturbing findings concerning silica levels at drilling sites and workers' exposure.
The NIOSH study took 111 samples at 11 sites in 5 states, including Pennsylvania. The results find that silica levels at all drilling sites exceeded safe levels and were as much as 10 times the safe level at some locations. These results should cause an immediate effort by regulators and companies to sharply reduce silica in the air at drilling sites and warrant more research. Here is the key NIOSH finding:
"At each of the 11 sites, full-shift samples exceeded occupational health criteria (e.g., the Occupational Safety and Health Administration calculated permissible exposure limit, the NIOSH recommended exposure limit, or the ACGIH threshold limit value), in some cases, by 10 or more times the occupational health criteria. Based on these evaluations, an occupational health hazard was determined to exist for workplace exposures to crystalline silica."