Related by context. Frequent words. (Click for all words.) 68 perc 65 trichlorethylene 58 toxic chemicals 57 solvents 56 vinyl chloride 56 volatile organic compounds 55 TCE 54 MTBE 54 VOCs 53 hexavalent chromium 53 hazardous chemicals 53 arsenic 53 harmful chemicals 52 carcinogens 52 pollutant 52 PCBs 52 pollutants 52 contaminant 52 groundwater contamination 51 carcinogen 51 contaminants 51 chemicals 51 contaminated groundwater 50 polychlorinated biphenyls 50 perchlorate 50 PFOA 50 toxic substances 50 gasoline additive 50 nitrogen oxide 50 phthalate 49 coal tar 49 phthalates 49 toxic pollutants 48 chlorine 48 septic systems 48 radium 48 triclosan 48 hydrogen sulfide 48 PBDEs 47 toxins 47 sulfur dioxide 47 asbestos fibers 47 hydrochloric acid 47 contaminated soil 47 PFCs 47 human carcinogen 47 particulates 47 nitrogen oxides 47 flame retardants 46 ozone 46 particulate emissions 46 PAHs 46 benzene 46 EPA 46 particulate pollution 46 dioxin 46 dioxins 46 chemical additives 46 hazardous substances 46 hazardous waste 46 refrigerants 46 pesticides 46 wastewater discharge 45 diesel exhaust 45 septic tanks 45 chromium 45 additive 45 suspended solids 45 dry cleaners 45 toxics 45 Clean Water Act 45 CFCs 45 groundwater 45 particulate matter 45 pesticide 45 USEPA 45 fecal bacteria 45 Superfund sites 44 Formaldehyde 44 asbestos contamination 44 carcinogenic 44 sulfur dioxide emissions 44 Benzene 44 Pollutants 44 atrazine 44 harmful pollutants 44 nitrates 44 detergents 44 Superfund site 44 Environmental Protection Agency 44 chloride 44 pollution 44 trace amounts 44 polluted 44 chemical 44 pesticide DDT 43 contamination 43 H2S 43 toluene 43 mercury emissions 43 fumigant