Related by context. Frequent words. (Click for all words.) 59 suspected carcinogen 56 benzene toluene 56 sulfuric 56 carbon tetrachloride 56 PCBs polychlorinated biphenyls 55 carcinogenic chemicals 55 benzene 54 Songhua river 53 toxic pollutants 53 chlorinated solvents 53 pollutants 53 polychlorinated biphenyls PCBs 52 acrylonitrile 52 Hydrogen sulfide 52 Sulfur dioxide 52 toxic chemicals 52 sulfur dioxide 52 vinyl chloride 52 methylene chloride 52 trichlorethylene TCE 51 Residues 51 pollutions 51 sulfur 51 toxic substances 51 hexane 51 nitrobenzene 51 pollutants emitted 51 additive MTBE 51 sulfur oxide 51 sulfur dioxide SO2 51 hydrofluoric acid 51 arsenic mercury 51 pollution 51 ammonia 51 MtBE 51 contaminants 50 pollutant 50 hydrogen sulfide 50 Diesel exhaust 50 heavily polluted 50 Toxic chemicals 50 polluted 50 tetrachlorethylene 50 Phenol 50 #,# dioxane 50 volatile organic compounds 50 VOC emissions 50 frac fluid 50 bromate 49 noxious gases 49 harmful contaminants 49 Hydrochloric acid 49 Pollutants 49 polluted groundwater 49 toxic vapors 49 chemicals 49 trichlorethylene 49 contaminant 49 hazardous chemicals 49 red sludge 49 hydrogen sulphide 49 toxic wastes 49 toxins 49 hydrogen chloride 49 Caustic Soda 49 Toluene 49 furan 49 chlordane 49 colorless liquid 49 dioxins 48 hydrogen fluoride 48 petroleum hydrocarbons 48 radioactive contaminants 48 poisonous chemicals 48 suspended solids 48 sulphates 48 wastewater discharges 48 respiratory irritant 48 methamidophos 48 mercury arsenic 48 disinfection byproducts 48 fecal coliform bacteria 48 potentially carcinogenic 48 contaminating groundwater 48 chemical solvents 48 E coli bacteria 48 flammable vapors 48 chemical vapors 48 dieldrin 48 Glycol 47 highly inflammable 47 fracking fluid 47 benzo pyrene 47 polycyclic aromatic hydrocarbons PAHs 47 sodium carbonate 47 noxious chemicals 47 industrial effluents 47 combustible gases 47 hazardous substances 47 coal tar 47 Seepage