Related by context. Frequent words. (Click for all words.) 71 fracking fluids 70 fracking fluid 64 fracking chemicals 60 hydraulic fracturing 60 MtBE 58 petroleum distillates 57 fracking 56 chemical additives 55 carcinogenic chemicals 55 frac fluid 55 Hydrogen sulfide 54 hexane 54 coalbed methane wells 54 Fracking 54 contaminating groundwater 54 methylene chloride 54 elemental sulfur 53 harmful contaminants 53 polluted groundwater 53 suspected carcinogen 53 carbon tetrachloride 53 fracing 53 Hydraulic fracturing 52 additive MTBE 52 corrosion inhibitor 51 dissolved solids 50 trichlorethylene TCE 50 hydrofracking 50 ethylbenzene 50 perchlorethylene 50 hydrofluoric acid 50 toxic chemicals 50 Hydrochloric acid 50 contaminants 50 Diesel exhaust 49 hydrogen sulfide 49 total dissolved solids 49 Carcinogens 49 Marcellus wells 49 chemicals 49 disinfection byproducts 49 phosphine 49 furan 49 sodium dichromate 49 groundwater contamination 49 kerogen 49 chlorinated solvents 49 Safe Drinking Water 49 corrosives 49 shale formations 49 methane hydrates 49 additives 48 engineered nanomaterials 48 contaminate groundwater 48 contaminant 48 tetrachlorethylene 48 livestock manure 48 mercaptan 47 flame retardant chemicals 47 PCBs polychlorinated biphenyls 47 polycyclic aromatic hydrocarbons PAHs 47 reinjection 47 #,# dioxane 47 hydrogen chloride 47 inorganic arsenic 47 benzene 47 chloramine 47 potassium permanganate 47 toxic substances 47 naturally occurring radioactive 47 chemical composition 47 COGCC 47 carcinogens 47 Aquifers 47 tritium leaks 47 solvents 47 carcinogenic substances 47 sulfur hexafluoride 47 xylene 47 Horizontal drilling 47 Toxic Chemicals 47 H2S 47 Sulfur dioxide 47 MTBE 47 Toxic Release Inventory 47 toxicants 46 contaminate drinking 46 groundwater 46 adulterants 46 methane 46 flammable vapors 46 drilling fluids 46 biogenic 46 engineered nanoparticles 46 ash ponds 46 SF6 46 gasoline additive 46 americium 46 arsenic mercury 46 Sulfate 46 contaminated groundwater