Related by context. Frequent words. (Click for all words.) 55 salt caverns 54 geological formations 54 potent greenhouse gas 53 carbon dioxide 53 Arctic permafrost 53 carbon dioxide CO2 52 clathrates 52 kerogen 52 sequester carbon dioxide 52 underground caverns 52 geologic formations 51 combustible gases 51 deplete oxygen 51 SF6 51 CO2 50 flue gases 50 underground salt caverns 50 reinjected 50 radioactive byproducts 49 groundwater aquifers 49 salt domes 49 methane hydrates 49 combustion gases 48 methane 48 pentane 48 shale formations 48 absorbs carbon dioxide 48 CO -2 48 odorless colorless gas 48 heat trapping carbon dioxide 48 Sulfuric acid 47 Yucca Mountain Nev. 47 aquifers 47 hydrocarbons 47 methane hydrate 47 injection wells 47 hydrocarbon gases 47 elemental sulfur 47 liquid hydrocarbons 47 gases 47 Carbon sequestration 47 underground aquifers 47 Billion Cubic Feet 47 BTEX 47 Radioactive waste 47 sulfur dioxide SO2 47 reinjection 47 benzene toluene 47 DAILY PRODUCTION 46 atmospheric pollutants 46 Contaminated soil 46 gas hydrates 46 regasification terminals 46 Reverse osmosis 46 reactor fuel rods 46 hydroxyl radicals 46 elemental mercury 46 Nitrogen oxides 46 Sulfur dioxide 46 emit CO2 46 peat bogs 46 fracturing fluids 46 Carbon dioxide 46 Permian basin 46 harmless nitrogen 46 miscible 46 distributes atmospheric 46 oxidising 46 storage caverns 46 reverse osmosis desalination 46 Volatile organic compounds 46 gaseous hydrogen 46 metal hydride 46 adipic acid 46 Hydraulic fracturing 46 lubricating oils 45 adsorbent 45 carbonic acid 45 volcanic vents 45 sulfur oxide 45 propane butane 45 poison gases 45 Aquifers 45 sulfur hexafluoride 45 shale deposits 45 gaseous fuels 45 nitrogen trifluoride 45 nitrogen oxide NOx emissions 45 gasified 45 Barnett Shale formation 45 Plasma Converter System 45 sludges 45 liquid hydrocarbon 45 suspected carcinogen 45 superheated steam 45 argon gas 45 exhaust gases 44 Highly radioactive 44 nitrous oxides 44 evaporation ponds 44 By Julian Pecquet