The Journal of Petroleum Technology has an interesting article on how the latest safety regulations require companies to reduce the level of dust on frac sites:

Airborne Dust Limits Finalized for Sand Use in Hydraulic Fracturing

The good news is that Propell has already developed technology with silica dust reduction in mind – independent testing of the Sandstorm system showed a maximum exposure of 0.014mg/m3 of total respirable particulates, well below the 0.05 mg/m3 limit of respirable silica alone.