Related by context. Frequent words. (Click for all words.) 61 Hydrogen sulfide 57 xylene 57 phosphine 56 hydrogen sulphide 55 carbon tetrachloride 54 harmful contaminants 54 hexane 54 suspected carcinogen 53 chlorinated solvents 53 fracking fluid 53 petroleum distillates 52 carcinogenic chemicals 52 H2S 52 acrolein 52 Methyl 52 naturally occurring radioactive 52 fracking fluids 52 contaminate groundwater 52 methylene chloride 51 solvents 51 toluene 51 perchlorethylene 51 contaminants 51 contaminant 51 Benzene 51 biogenic 51 tetrachlorethylene 50 Triclosan 50 Refrigerant 50 hydrogen sulfide 50 potentially carcinogenic 50 benzene 50 sludges 50 fracking chemicals 50 Coal seam 50 Sulfur dioxide 50 Toluene 50 pollutant 50 corrosives 50 acute toxicity 49 sulphates 49 Hydrochloric acid 49 Dioxins 49 polycyclic aromatic hydrocarbons PAHs 49 trichlorethylene TCE 49 Inhalation 49 PCBs polychlorinated biphenyls 49 mercaptan 49 Sulfate 49 naturally occurring substance 48 colorless liquid 48 hydrofluoric acid 48 Nitrates 48 furans 48 hydrogen chloride 48 disinfection byproducts 48 Acrylamide 48 #,# dioxane 48 gases 48 polychlorinated biphenyls PCBs 48 chemicals 48 carcinogen 48 dispersant chemicals 48 colorless odorless 48 condensate 48 H#O# 48 frac fluid 48 PAHs 48 MtBE 48 Glycol 48 Phenol 48 polybrominated diphenyl ethers 48 hydrocarbons 48 Nitrate 48 lubricating oils 48 contaminating groundwater 48 sulfur 48 dieldrin 47 toxin 47 dissolved solids 47 Ammonium Nitrate 47 Legionella bacteria 47 alkyl 47 radionuclides 47 SF6 47 chemical 47 contaminate drinking 47 Fluorine 47 polycyclic aromatic hydrocarbons 47 legionella bacteria 47 chemical solvents 47 Solvents 47 adsorbent 47 Ethane 47 residues 47 inorganic arsenic 47 kerogen 47 Pollutants 47 Ammonia 47 sulfur hexafluoride 47 carcinogenic substances