dust

A study by the National Institute of Occupational Safety found that workers involved with hydraulic fracturing are often exposed to dangerously high levels of silica.

Silica sand is used in fracking fluid, and breathing dust from the material can cause lung diseases and cancer.

The sites that were monitored for the study were all outside Wyoming, but John Robitaille with the Petroleum Association of Wyoming says companies here still need to take the matter seriously.