| E0 | E0 gasoline |
| E10 | E10 gasoline |
| E15 | E15 gasoline |
| E85 | E85 fuel |
| EA | Endangerment assessment; Enterprise architecture; Environmental assessment; Environmental audit |
| EAB | Environmental Appeals Board |
| EAF | Electric arc furnace |
| EAF Steelmaking Facility | Electric arc furnace steelmaking facility |
| EBCDIC | Extended binary coded decimal interchange code |
| EBCR | Eastern bituminous coal refuse |
| EBDCs | Ethylenebisdithiocarbamic acid, salts and esters (1.0) |
| EBM | Energy balance model |
| EBS | Emergency broadcasting system |
| EC | Earth coverage; Escherichia coli |
| EC50 | Median effective concentration |
| ECA | Emission control area |
| ECC | ECMS coordination committee |
| ECD | Electron capture detector |
| ECEL | Existing chemical exposure limit |
| ECEL Action Level | Existing chemical exposure limit action level |
| ECF Process | Elemental chlorine-free process |
| ECG | Electrocardiogram test |
| ECM | Electronic control module; Enterprise content management |
| ECMS | Enterprise content management system |
| ECNIMS | Electron capture negative ion mass spectrometry |
| ECO | Extended cookout |
| ED₁₀ | Effective dose |
| EDB | Ethylene dibromide |
| EDC | Enterprise data catalog |
| EDD | Enforcement decision document |
| EDF | Empirical distribution function |
| EDG | Environmental dataset gateway |
| EDI | Electronic Data Interchange |
| EDL | Estimated detection limit |
| EDO | Environmental data operations |
| EDP | Electrodeposition |
| EDR | Environmental data registry |
| EDS | Engine dynamometer schedule |
| EE | Environmental equity |
| EEC | Estimated environmental concentration |
| EECIP | E-Enterprise Community Inventory Platform |
| EED | Estimated exposure dose |
| EEG | Evaporative emission generator |
| EEPS | Energy efficiency portfolio standards |
| EF | Emission factor; Exposure frequency |
| EFR | External floating roof |
| EFR Failure | External floating roof failure |
| EFT | Electronic funds transfer |
| EFX | Effects |
| E.G.L. | Energy grade line |
| EGR | Exhaust gas recirculation |
| EGU | Electric generating unit |
| EH | Redox potential |
| EHS | Extremely hazardous substance |
| EI | Emission inventory; Erodibility index |
| EIA | Economic impact analysis; Energy Information Administration; Environmental impact assessment |
| EIAG | Emission inventory and analysis group |
| EIAPP Certificate | Engine International Air Pollution Prevention under Annex VI certificate |
| EID | Emerging infectious disease; Environmental information document |
| EIL Policies | Environmental impairment liability policies |
| EIP | Economic incentive program |
| EIS | Emission inventory system; Emissions inventory system; Environmental impact statement; Environmental indicator |
| E&IT | Electronic and information technology |
| EJ | Environmental justice |
| EJ Index | Environmental justice index |
| EL | Emission limitation; Exposure level |
| ELAB | Environmental Laboratory Advisory Board |
| ELG | Effluent limitation guideline; Effluent limitations guideline |
| ELGs | Effluent limitation guidelines and standards |
| ELISA | Enzyme-linked immunosorbent assay |
| ELWK | Equivalent live weight killed |
| EM | Emission table |
| EM Geophysics | Electromagnetic geophysics |
| EM Induction | Electromagnetic induction |
| E-MAIL | Electronic mail |
| E-Manifest | Electronic manifest |
| E-Manifest System | Electronic manifest system |
| EMAP | Environmental Monitoring and Assessment Program |
| Emergency Stationary RICE | Emergency stationary reciprocal internal combustion engine |
| E.M.F. | Electromotive force |
| EMF | Ectomycorrhizal fungus; Emissions modeling framework |
| EMI Coating | Electromagnetic interference coating |
| EMMC process | Entrapped mixed microbial cells process |
| EMPACT | Environmental monitoring for public access and community tracking |
| EMR | Electromagnetic radiation |
| EMR Hazard | Electromagnetic radiation hazard |
| EMS | Electromagnetic spectrum; Environmental management systems |
| EMT | Emerging technology |
| EMTS | EPA moderated transaction system |
| EN | Environmental information exchange network |
| ENDS | Exchange network discovery services |
| Enhanced I&M | Enhanced inspection and maintenance |
| EnPPA | Environmental performance partnership |
| ENR | Enhanced nutrient removal technology |
| ENSC | Exchange network services center |
| ENSO | El Niño - Southern Oscillation |
| EO | Ethylene oxide; Executive Order |
| E.O. 12873 | Executive Order 12873 |
| E.O. 13101 | Executive Order 13101 |
| E.O. 13423 | Executive Order 13423 |
| EOR | Enhanced oil recovery |
| EOX | Extractable organic halide |
| EP | Emergency Preparedness; Emission process table; End-use product; Extraction procedure |
| EPA | United States Environmental Protection Agency |
| EPA Reg. No | EPA registration number |
| EPA TSCA Title VI Laboratory AB | EPA TSCA Title VI laboratory accreditation body |
| EPA TSCA Title VI Product AB | EPA TSCA Title VI product accreditation body |
| EPA TSCA Title VI TPC | EPA TSCA Title VI third-party certifier |
| EPA-505/2-90-001 | Technical support document water quality-based toxics control |
| EPC | Exposure point concentration |
| EPCRA | Emergency Planning & Community Right-to-Know Act |
| EPD® | Environmental product declaration |
| EPF | Ecological production function |
| EPID | Epidemiological studies |
| epi-triad | Epidemiology triad |
| EPP | Environmentally preferable purchasing |
| EPPU | Elastomer product process unit |
| EPS | Encapsulated PostScript; Expandable polystyrene |
| EPS Resin | Expandable polystyrene resin |
| EQIP | Environmental Quality Incentives Program |
| Equipment in GHG Service | Equipment in fluorinated greenhouse gas service |
| Equipment in HAP ABA Service | Equipment in hazardous air pollutant auxiliary blowing agent service |
| Equipment In HAP Service | Equipment in hazardous air pollutant service |
| Equipment in Metal HAP Service | Equipment in metal hazardous air pollutant service |
| Equipment in Organic HAP Service | Equipment in organic hazardous air pollutant service |
| Equipment in Target HAP Service | Equipment in target hazardous air pollutant service equipment |
| Equipment in VHAP Service | Equipment in volatile hazardous air pollutant service |
| Equipment in VOC Service | Equipment in volatile organic compound service |
| ER | Electrical resistivity; Emergency Response; Emission release table; Extra risk; Extrarespiratory |
| ERA | Environmental risk assessment |
| ERAGS | Ecological risk assessment guidance for Superfund |
| ERNS | Emergency response notification system |
| ERP | Emergency response plan |
| ERS Exclusion | Eligible response site exclusion |
| ERT | Environmental Response Team |
| E.S. | Effective size |
| ESA | Endangered Species Act; Environmental site assessment |
| ESD | Explanation of significant differences |
| ESI | Enforcement sensitive information; Expanded site inspection |
| ESP | Electrostatic precipitator |
| ESPF | Ecosystem service production function |
| ESR Spectroscopy | Electron spin resonance spectroscopy |
| Essential MDI | Essential metered dose inhaler |
| Essential-Use CFCs | Essential-use chlorofluorocarbons |
| EST | Eastern Standard Time; Expressed sequence tag |
| ESU | Evolutionarily significant unit |
| ET | Ecotox thresholds; Emissions trading; Exposure time |
| ET-AAS | Electrothermal atomic absorption spectroscopy |
| ETAM | Ecotoxicological assessment |
| ETBE | Ethyl tertiary Butyl Ether |
| ETI | Evapotranspiration/Infiltration Process |
| ETL | Extract, transform, load |
| ETS | Environmental tobacco smoke |
| EU | Electric utility; Emission unit table |
| EUPs | Experimental use permit |
| EV | Electric Vehicle; Electron volt |
| EVE | Exchange value equivalent |
| EVOI | Expected value of information |
| EVR | Effective ventilation rate |
| Excess Lifetime Cancer Risk | Cancer risk |
| Existing CCR Land | Existing coal combustion residuals landfill |
| Existing HWM Facility | Existing hazardous waste management facility |
| Existing MSWLF Unit | Existing municipal solid waste landfill unit |
| Existing OCS Source | Existing outer continental shelf source |
| Exosphere | Atmosphere vertical layer |
| Exploratory OCS Source | Exploratory outer continental shelf source |
| EZVI | Emulsified zero-valent iron |