Of the more than 200 compounds used in hydraulic fracturing fluids, eight are toxic to mammals and the
A Marcellus Shale fracking operation
health risks of roughly one-third are unknown, according to researchers at Lawrence Berkeley National Lab. Hydraulic fracturing, also known as fracking, is a drilling technique that releases natural gas and oil by injecting fluids with chemical additives deep into rock formations. The research team tracked down substances commonly used as fracking additives and found they include gelling agents to thicken the fluids, biocides to inhibit microbial growth, and compounds to prevent pipe corrosion. The industry claims the additives are non-toxic and food-grade, and while that is true in some cases, the researchers note, most fracking compounds require treatment before they can be safely released into the environment. Moreover, a number of chemicals that could pose health risks, such as corrosion inhibitors and biocides, are used in reasonably high concentrations in fracking fluids, the researchers note.