Environment terminology · MLC-0121

Environment terms: O (859)

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• O HorizonSoil horizon which has a high percentage of organic matter in various stages of decomposition
• O₃While ozone in the stratosphere can help protect us from ultraviolet rays, ground-level ozone poses health...
• OahuThe drainage on the island of Oahu; and associated waters. Hawaii. Area = 630 sq.mi.
• oak openingA savannah on rich, mesic soils with mostly bur or white oak.
• Oak SavannaA transitional community between prairie and forest, sustained by fires, characterized by scattered...
• Obesity1. Having a high amount of body fat (body mass index [BMI] of 30 or more).
• Object Oriented PlatformA type of user interface that models systems using a collection of cooperating “objects.” These objects are...
• ObjectiveSpecific results or effects of a program's activities that must be achieved in pursuing the program's...
• Objective, environmentalOverall environmental goal, arising from the environmental policy, that an organization sets itself to...
• Objective FunctionChoice of function that is optimized for maximum likelihood estimation.
• Objectivity1. One of three main components of quality in EPA's Information Quality Guidelines. Objectivity includes...
• Object-Oriented PlatformsType of user interface that models systems using a collection of cooperating "objects." These objects are...
• Obligate AerobeOrganisms that require the presence of molecular oxygen (0₂) for their metabolism.
• obligate aerobesOrganisms that require the presence of molecular oxygen (0₂) for their metabolism.
• Obligate AnaerobeOrganisms for which the presence of molecular oxygen is toxic. These organisms derive the oxygen needed for...
• obligate anaerobesOrganisms for which the presence of molecular oxygen is toxic. These organisms derive the oxygen needed for...
• Obligate Anaerobic RespirerMicroorganisms which metabolize energy anaerobically and can't live in areas with atmospherically-normal...
• Obligate FermenterMicroorganisms that produce their energy only by fermentation
• Obligate ParasiteA microorganism that cannot live without its host
• ObligatedWhen awarding funding, the U.S. government enters a binding agreement called an obligation. The government...
• Obligated PartyRefiner that produces gasoline or diesel fuel within the covered location, or any importer that imports...
• ObligationWhen awarding funding, the U.S. government enters a binding agreement called an obligation. The government...
• OBLIGATIONSThe amounts of orders placed, contracts and grants/subgrants awarded, goods and services received and similar...
• Observation1. A data collection strategy in which the activities of subjects are visually examined. The observer...
• Observation Result UncertaintyThe measure of uncertainty of an observation result. Numerical value(s) indicating the reliability of the...
• observational epidemiologic study1. A study in which the investigators do not manipulate the use of, or deliver, an intervention (e.g., do not...
• Observational Research1. Human research that does not meet the definition of research involving intentional exposure of a human...
• Observational RunObservation of visible emissions from topside port lids, offtake systems, coke oven doors, or the charging of...
• observational study1. A study in which the investigators do not manipulate the use of, or deliver, an intervention (e.g., do not...
• Observational TechniquesData collection strategies which use observation of subjects as a means to collect data. These techniques...
• Observationally Based MethodMethod of research where the research is conducted by systematically viewing and recording behaviors of...
• Observed ContaminationObserved contamination is established for the soil exposure pathway only by chemical analysis. The minimum...
• Observed ReleaseAn observed release is established for the ground water, surface water, or air migration pathway either by...
• Observed/Expected Ratio of Taxa LossA ratio comparing the number of taxa expected (E) to exist at a site to the number that are actually observed...
• Obsolete Control Measure1. A class of control measure that may exist on some historical installations but is not likely to be used...
• Obsolete ScrapMetal containing objects that have finished their useful lives, but which can be melted down, and their...
• occludeTo cause to become obstructed or closed and thus prevent passage either into or from.
• Occluded FrontA composite of two fronts, formed as a cold front overtakes a warm or quasi-stationary front. Two types of...
• Occupant Emergency PlanA document to establish a crisis management program in the event of emergencies that may arise at the...
• Occupational CarcinogenCarcinogens encountered through occupational exposure. The carcinogens can be of any type: chemicals...
• Occupational DermatitisA recurrent contact dermatitis caused by substances found in the work place. (MSH2003_2003_05_12)
• Occupational ExposureContact with a substance by swallowing, breathing, or touching the skin or eyes done while working
• Occupational GroupA group of related occupations; examples: sales occupations and service occupations.
• Occupational Health and SafetyConditions and factors that affect, or could affect, the health and safety of employees or other workers...
• Occupational Health and Safety Assessment Series 18001:2007The Occupational Health and Safety Assessment Series (OHSAS) standard developed by the British Standards...
• Occupational Illness1. Any abnormal condition or disorder, other than one resulting from an occupational injury, caused by...
• Occupational InjuryAny injury such as a cut, fracture, sprain, amputation, etc., which results from a work-related event or from...
• Occupational mobility1. An indicator of the frequency at which workers change from one occupation to another.
• Occupational Safety & Health ActTo assure safe and healthful working conditions for working men and women, by authorizing enforcement of the...
• Occupational Safety and Health Act of 1970(0-shuh) The Williams-Steiger Occupational Safety and Health Act of 1970 (OSHA) is a law designed to protect...
• Occupational Safety and Health AdministrationThe Occupational Safety and Health Administration, since its inception in 1971, aims to ensure employee...
• Occupational Safety and Health Administration's Permissible Exposure LimitOccupational Safety and Health Administration's permissible exposure limit expressed as a time-weighted...
• Occupational tenureThe cumulative number of years a person worked in his or her current occupation, regardless of number of...
• Occupied SpaceThe space within a building or structure that is normally occupied by people, and that may be conditioned...
• Occupied ZoneThe region within an occupied space between planes 3 and 72 in. (75 and 1800 mm) above the floor and more...
• OccurrenceAn event that results in an insured loss.
• Occurrence Based CoverageThe trigger of insurance coverage is the occurrence, not the claim; therefore, the claim can be made anytime...
• OceanLarge unenclosed waterbody that is farther than one nautical mile from a baseline defined by the land points...
• Ocean Acidification1. Increased concentrations of carbon dioxide in sea water causing a measurable increase in acidity (i.e., a...
• Ocean Bank/PlateauA mound-like or ridge-like elevated area on the seafloor; it may have a modest-to-substantial extent...
• Ocean Biogeochemical ComponentDefines the water column by identifying factors including constituent composition (e.g., chlorophyll maximum...
• Ocean Current1. Broadly, currents in the ocean - tidal or nontidal, permanent or seasonal, horizontal or vertical -...
• Ocean Discharge WaiverA variance from Clean Water Act requirements for discharges into marine waters.
• Ocean Disposal SiteFinally approved and precise geographical area within which ocean dumping of wastes is permitted under...
• Ocean Drilling RigLarge structures built to house workers and machinery needed to drill wells in the ocean bed in order to...
• Ocean DumpingDisposition of material: Provided, That it does not mean a disposition of any effluent from any outfall...
• Ocean Dumping Adverse Effects MinimizationThere are many actions which can be undertaken in response to § 203.10(d) to minimize the adverse effects of...
• Ocean Dumping Ban ActTo amend the Marine Protection, Research, and Sanctuaries Act of 1972 to provide for termination of ocean...
• Ocean IceFrozen form of water, which is less dense than liquid water; ice floats on the surface of liquid water...
• Ocean MixingProcesses that involve rates of advection, upwelling/ downwelling, and eddy diffusion and that determine how...
• Ocean Origin AerosolAerosol consisting of ocean materials, particularly sea salt
• Ocean Shore HabitatThe natural environment provided by the ocean shore in which animals and plants live
• Ocean StackA rocky subaerial landform consisting of a steep (and often vertical) column or columns of rock in the sea...
• Ocean TankerSelf or non-self-propelled vessel constructed or adapted to transport liquid, solid or gaseous commodities or...
• Ocean Waters1. Those coastal waters landward of the baseline of the territorial seas, the deep waters of the territorial...
• Ocean-Going VesselVessels that are equipped with engines meeting the definition of “Category 3” in 40 CFR 1042.901.
• Ocean-Going Vessel FuelAny marine residual fuel (whether burned in ocean waters, Great Lakes, or other internal waters); Emission...
• Oceanic BankAn elevated area above the surrounding seafloor that rises near the surface. Banks generally are low-relief...
• Oceanic BasinGeneral term for an area of the seafloor or land surface that lies below the surrounding bottom or terrain...
• Oceanic Boundary LayerLayer formed at the interface between water and another water mass (or solid interface) where frictional...
• Oceanic CaveA natural passage extending beneath the Earth’s oceanic surface.
• Oceanic ChannelA general term for a linear or sinuous depression on an otherwise more flat area (for example, a valley- or...
• Oceanic Cone1. A type of submarine, fan-shaped deposit - especially a deep-sea fan associated with a major active delta...
• Oceanic CrustThe relatively thin, dense crust that forms the ocean basins.
• Oceanic FrontLinear features formed at the conjunction of two or more water masses with different properties. Fronts are...
• Oceanic GeoformPhysical, coastal and seafloor structures.
• Oceanic ImpactIncreased concentrations of carbon dioxide in sea water causing a measurable increase in acidity (i.e., a...
• Oceanic LedgeBedding planes that are exposed (either on the surface or at depth) often form ledges that have a high...
• Oceanic PassagewayA generally narrow passage way, open on both ends, through a shoal. In coral reef settings this feature...
• Oceanic PlateauA mound-like or ridge-like elevated area on the seafloor; it may have a modest-to-substantial extent...
• Oceanic Spreading RidgeAn oceanic spreading ridge is the fracture zone along the ocean bottom where molten mantle material comes to...
• OceanographyThe science that deals with the ocean and its phenomena. (Webster, 3d ed)
• OcellusAn eye-like spot, usually surrounded with a ring of a lighter color, e.g. the ocellus toward the caudal...
• OchlockoneeThe coastal drainage and associated waters from the Aucilla River Basin boundary to and including the...
• Ochratoxin AProduced by Aspergillus sp. (A. ochraceus) and Penicillium sp. (P. viridicatum) Highest levels usually found...
• Ocimum spp.Basil (Ocimum basilicum L.); Basil, American (Ocimum americanum L.); Basil, Greek (Ocimum minimum L.); Basil...
• Octanol/air partition coefficient (Kₒₐ)Kₒₐ describes partitioning between air and aerosol particles, air and foliage, and air and soil and is an...
• Octanol-air partition coefficient (log value)Ratio of a chemical that has reached equilibrium in adjacent fractions of octanol and air. This ratio is used...
• octanol/water partition coefficientA coefficient representing the ratio of the solubility of a compound in octanol (a non-polar solvent) to its...
• Octanol/water partition coefficient (K(ow))Partitioning of organic chemicals between octanol (a nonaqueous, nonpolar solvent and reasonable surrogate...
• Octanol-water partition coefficient (log value)Ratio of a chemical that has reached equilibrium in adjacent fractions of octanol and water. This ratio is...
• Octave Band AttenuationAmount of sound reduction determined according to the measurement procedure of § 211.206 for one-third octave...
• Octyl MethoxycinnamateEster that is a uv filter used in sunscreens
• Octylphenolp-(1,1,3,3-tetramethylbutyl)phenol. An alkylphenol surfactant used in household products
• OcularPertaining to or affecting the eye
• Odds Ratio1. A relative measure of the difference in exposure between the diseased (cases) and not diseased (controls)...
• OdorA quality of gases, liquids, or particles that stimulates the olfactory organ or sense of smell.
• Odor Character or QualityThe property of the odor sensation that permits a person to distinguish odors of different substances based...
• Odor ControlEliminating of offensive odors.
• Odor DescriptorAdjective given to an odor such as "floral," "caramel," "putrid."
• Odor PervasivenessThe rate of decrease of odor perception associated with the decrease in odorant concentration.
• Odor Threshold1. The lowest concentration of a substance in air that can be smelled. Odor thresholds are highly variable...
• OdorantA substance that stimulates the olfactory receptors.
• OdorimetryMeasurement of olfactory sensations.
• OECD Council DecisionA multilateral agreement by the Organization for Economic Cooperation and Development that establishes...
• OECD GuidelinesTesting guidelines prepared by the Organization of Economic and Cooperative Development of the United...
• OFFERA term formerly used to describe the act of requesting NARA's one-time approval of the immediate transfer of...
• off-gas treatment systemRefers to the unit operations used to treat (i.e. condense, collect, or destroy) contaminants in the purge...
• Off-GassingThe production of gases from the chemical deterioration of a substance over time, and the release of gases...
• Off-Grid SystemEnergy-generating systems that are not interconnected directly into an electrical grid. Energy produced in...
• Off-Highway Motorcycle1. Meaning given in 40 CFR 1051.801. (Note: highway motorcycles are regulated under 40 CFR part 86.)
• OFFICE AUTOMATIONThe use of automated or electronic equipment, such as computers, for office operations.
• Office BuildingCommercial building where at least 50 percent of the floor space is used for administrative or bureaucratic...
• Office FurnitureFurniture typically used in offices, including seating, desks, storage units, file cabinets, tables, and...
• Office of Air and RadiationSee http://www.epa.gov/oar/. EPA's Office of Air and Radiation (OAR) deals with issues that affect the...
• Office of Air Quality Planning and StandardsOffice of Air Quality Planning and Standards (of EPA's Office of Air, located in RTP, NC). Develops national...
• Office of Civil RightsDirector of the Office of Civil Rights, EPA Headquarters or his/her designated representative.
• Office of Enforcement and Compliance AssuranceSee http://www.epa.gov/enforcement/index.html. The Office of Enforcement and Compliance Assurance (OECA) is...
• Office of General CouncilThis EPA Office provides legal advice and service to all organizational elements of EPA, including the Office...
• Office of Modeling, Monitoring Systems, and Quality AssuranceThe office within EPA's Office of Research and Development responsible for EMAP management within the Agency.
• Office of Pesticide Programs1. This EPA Office registers and regulates pesticides.
• Office of Pollution Prevention and ToxicsSee http://www.epa.gov/opptintr. The Office of Pollution Prevention and Toxics (OPPT), formerly the Office of...
• Office of Prevention, Pesticides and Toxic SubstancesSee http://www.epa.gov/oppts/. EPA's Office of Prevention, Pesticides and Toxic Substance (OPPTS) plays an...
• Office of Research and DevelopmentSee http://www.epa.gov/ORD/. The Office of Research and Development (ORD) is the scientific and technological...
• Office of Science Coordination and PolicySee http://www.epa.gov/oscpmont/. The Office of Science Coordination and Policy (OSCP), newly created in...
• Office of Solid WasteSee http://www.epa.gov/aboutepa/oswer.html. The Office of Solid waste (OSW) operates under authority of the...
• Office of Solid Waste and Emergency ResponseSee http://www.epa.gov/oswer/. The Office of the Assistant Administrator for Solid Waste and Emergency...
• Office of Superfund Remediation and Technology InnovationSee http://www.epa.gov/superfund/partners/osrti/index.htm. Office of Superfund Remediation and Technology...
• Office of Transportation and Air QualityOffice of Transportation and Air Quality (of EPA's Office of Air, located in Ann Arbor, MI). Responsible for...
• Office Paper1. Refers to high-grade papers such as copier paper, computer printout, and stationery. These papers are...
• Official Emission Result1. Measured emission rate for an emission-data unit.
• OFFICIAL FILEThe administrative file for each assistance agreement (or each application or unsolicited proposal) that is...
• Official Information DisseminationOfficial Information Dissemination includes all efforts to provide official government information to...
• Official submissionThe current data values for a given inventory cycle that an S/L/T has submitted to the EIS Production...
• Official version of the State statutes and regulationsThe version of the state's statutes and regulations that is acknowledged by the state as legally enforceable...
• OFF-LINENot under the direct control of a computer. Refers to data on a medium, such as a magnetic tape, not directly...
• Off-Line EquipmentUnwind or feed section, which may include more than one unwind or feed station (such as on a laminator); a...
• Off-Line StorageA type of storage that requires detention facilities (basins or tunnels) and facilities for pumping storm...
• Off-Road MotorcycleAny motorcycle that is not a street motorcycle or competition motorcycle.
• Offroad Utility VehicleNonroad vehicle that has four or more wheels, seating for two or more persons, is designed for operation over...
• Off-Road Vehicle EmissionEmissions from vehicles that are not intended to be safely driven on roads or highways
• Offset1. The difference between the actual value and the desired value (or set point); characteristic of...
• Offset PlanPlan pursuant to part 77 of this chapter for offsetting excess emissions of sulfur dioxide that have occurred...
• Offset printingThe most commonly used printing method, where the printed material does not receive ink directly from a...
• Offset WellAn existing wellbore close to a proposed well that provides information for planning the proposed well.
• Offset wellsAn existing wellbore close to a proposed well that provides information for planning the proposed well.
• OffsetsA concept whereby emissions from proposed new or modified stationary sources are balanced by reductions from...
• Offshore1. In beach terminology, the comparatively flat zone of variable width, extending from the shoreface to the...
• Offshore facility1. Any facility located in, on, or under any of the navigable waters of the United States, which is not a...
• Offshore Liquefied Natural Gas Import TerminalAny facility located in waters defined in 40 CFR 435.10 or 40 CFR 435.40 that liquefies, re-gasifies...
• Offshore oil drilling, production, or workover facilitiesMay include all drilling or workover equipment, wells, flowlines, gathering lines, platforms, and auxiliary...
• Offshore (Open) Waters(1) The waters extending from 5 miles to the midpoint of the Great Lakes. (2) That portion of the oceans...
• Offshore Platform Gas TurbineAny stationary gas turbine located on a platform in an ocean.
• Off-site1. Off-site facilities (or receiving facilities) receive transfers of chemicals from TRI on-site (or...
• OffsiteAreas beyond the property boundary of the stationary source, and areas within the property boundary to which...
• Offsite DisposalSending used organic HAP solvent or coatings outside of the facility boundaries for disposal.
• Off-Site Facility1. A hazardous waste treatment, storage or disposal area that is located away from the generating site.
• Off-Site MaterialMaterial that meets all of the criteria specified in paragraph § 63.680(b)(1) of this subpart but is not one...
• Off-Site Material Management UnitTank, container, surface impoundment, oil-water separator, organic-water separator, or transfer system used...
• Off-Site Material ServiceAny time when a pump, compressor, agitator, pressure relief device, sampling connection system, open-ended...
• Off-Site Material StreamOff-site material produced or generated by a particular process or source such that the composition and form...
• OFF-SITE STORAGEA facility other than an agency's normal place of business where vital records are stored for protection.
• Off-SpecificationPaint or coating material that does not meet quality or customer specifications.
• Off-Specification Used OilUsed oil that is tested and does not meet given parameters for arsenic, cadmium, chromium, flash point, lead...
• Offstream UseWater withdrawn from surface or groundwater sources for use at another place.
• Offstream UsesWater withdrawn from surface or ground water sources for use at another place.
• Ogeechee-SavannahThe coastal drainage and associated waters from and including the Savannah River Basin to the Altamaha River...
• Ohio RegionThe drainage of the Ohio River Basin, excluding the Tennessee River Basin. Includes parts of Illinois...
• Ohm1. The unit of electrical resistance. The resistance of a conductor in which one volt produces a current of...
• Ohm-meterUnit of electrical resistivity; the resistivity of 1 m3 of material, which has a resistance of 1 ohm when...
• OH&S Management SystemPart of an organization's management system used to develop and implement its OH&S policy and manage its OH&S...
• OH&S ObjectiveOH&S goal, in terms of OH&S performance, that an organization sets itself to achieve. Note: May also be...
• OH&S PerformanceMeasureable results of an organization's management of its OH&S risks. OH&S performance measurement includes...
• OH&S PolicyOverall intentions and direction of an organization related to its OH&S performance as formally expressed by...
• Oidium sppPlant pathogens causing powdery mildew diseases.
• Oil1. Oil, a liquid fossil fuel, is formed from layers of buried plants and animals that have been subjected to...
• Oil & Gas ExtractionThis industry comprises establishments primarily engaged in operating and/or developing oil and gas field...
• Oil and Gas FieldOil and gas fields identified in the United States as defined by the Energy Information Administration Oil...
• Oil and Gas ProductionThe lifting of oil and gas to the surface and gathering, treating, field processing (as in the case of...
• Oil and Gas Production ChemicalSubstances used in the production of oil or natural gas
• Oil and Gas Production WasteGas and oil drilling muds, oil production brines, and other waste associated with exploration for, or...
• Oil and Gas Waste1. Refers to gas and oil drilling muds, oil production brines, and other wastes associated with the...
• Oil and Grease1. Total recoverable oil and grease (n-hexane extractable material).
• Oil and Grease as HEM1. Total recoverable oil & grease measured as n-hexane extractable materials.
• Oil and Natural Gas Production FacilityAll of the air pollution emitting units and activities located on or integrally connected to one or more oil...
• Oil and Natural Gas WellSingle well that extracts subsurface reservoir fluids containing a mixture of oil, natural gas, and water.
• Oil by UseVarious types of oils commercially available categorized by application.
• OIL DatabaseEPA's OIL database contains information on Spill Prevention, Control and Countermeasure (SPCC) and Facility...
• Oil DesulfurizationWidely used precombustion method for reducing sulfur dioxide emissions from oil-burning power plants. The oil...
• Oil Discharge ClassificationThe following size classes of oil discharges which are provided as guidance to the OSC and serve as the...
• Oil Discharge Cleanup1. Cleanup of a discharge of oil into or upon the navigable waters of the United States or adjoining...
• Oil Discharge Clean-up TechnologyTechnologies and devices which are used in cleaning up oil spills on bodies of water.
• Oil Discharge EmergencyOccurs when oil has been released. These releases can be the result of intentional actions or unintentional...
• Oil Discharge Size ClassThe following size classes of oil discharges which are provided as guidance to the OSC and serve as the...
• Oil Discharge Size ClassificationThe following size classes of oil discharges which are provided as guidance to the OSC and serve as the...
• Oil DispersantThe active ingredients are solvents and emulsifiers which are used to split oil drops in water into smaller...
• Oil FieldArea where petroleum is or was removed from the Earth.
• Oil Field Disposal Well UIC Class 1Well with a UIC Class I permit that meets the definition in 40 CFR 144.6(a)(2) and receives eligible fluids...
• Oil Field Disposal Well UIC Class 2Well with a UIC Class II permit where wastewater resulting from oil and natural gas production operations is...
• Oil Field ResearchA field with a GOR less than 20,000 (in cubic feet/barrel).
• Oil FingerprintingA method that identifies sources of oil and allows spills to be traced to their source.
• Oil Fired Boiler SubcategoryAny boiler that burns any liquid fuel and is not in either the biomass or coal subcategories. Gas-fired...
• Oil Injection Metering SystemPart of the engine fuel system which includes components involved in the transport, metering, and mixture of...
• Oil Pollution Act1. To protect navigation from obstruction and injury by preventing the discharge of oil into the coastal...
• Oil Production Facility1. Any mobile or fixed, onshore or offshore building, property, parcel, lease, structure, installation...
• Oil Removal1. Removal of the oil from the water and shorelines or the taking of such other actions as may be necessary...
• Oil Removal Contingency PlanWhen it is determined that the installation of diversionary structures and equipment listed in 40 CFR Part...
• Oil Reservoir1. An underground pool of liquid consisting of hydrocarbons, sulfur, oxygen, and nitrogen trapped within a...
• Oil sandA naturally occurring mixture of sand, clay, silt, rocks, other minerals and bitumen, also known as tar sands...
• Oil SandsCombination of clay, sand, water, and bitumen, a heavy black viscous oil. Oil sands can be mined and...
• Oil SeparatorMechanism which removes at least 50 percent of the oil entrained in the oil/refrigerant mixture exiting the...
• Oil shale1. Underground formation of a fine-grained sedimentary rock containing varying amounts of kerogen, a solid...
• Oil SolidifierSubstances that through a chemical reaction cause oil to become a cohesive mass, preventing oil from...
• Oil SpillAn accidental or intentional discharge of oil which reaches bodies of water. Can be controlled by chemical...
• Oil Spill Liability Trust FundThe fund established under section 9509 of the Internal Revenue Code of 1986 (26 U.S.C. 9509). [40 CFR 300.5...
• Oil Spill Removal OperationEntity that provides oil spill response resources, and includes any for-profit or not-for-profit contractor...
• Oil TankStationary unit that is constructed primarily of nonearthen materials (such as wood, concrete, steel...
• Oil Well1. A well completed for the production of crude oil from at least one oil zone or reservoir.
• Oil-Based Drilling FluidContinuous phase of the drilling fluid consists of diesel oil, mineral oil, or some other oil, but contains...
• Oilfield Brake BlocksFriction brake blocks component in drawworks used in the hoisting mechanism for oil well drilling rigs.
• Oilfield BrineWastewater produced along with crude oil and natural gas from oilfield operations.
• Oil-Filled Operational EquipmentEquipment that includes an oil storage container (or multiple containers) in which the oil is present solely...
• Oil-Fired BoilerFurnace or boiler used for combusting fuel oil for the primary purpose of producing steam or hot water by...
• Oil-Fired Electric Utility Steam Generating Unit1. Electric utility steam generating unit meeting the definition of “fossil fuel-fired” that is not a...
• Oil-Fired Steam Generating UnitElectric utility steam generating unit meeting the definition of “fossil fuel-fired” that is not a coal-fired...
• Oil-Fired Unit1. Stationary combustion unit that derives more than 50 percent of its annual heat input from the combustion...
• Oil/Gas Production TurbineAny stationary gas turbine used to provide power to extract crude oil/natural gas from the earth or to move...
• Oil/Gas Transportation TurbineAny stationary gas turbine used to provide power to extract crude oil/natural gas from the earth or to move...
• OilingForm surface is treated with a release agent to keep concrete from bonding with the form.
• OilseedFollowing agricultural products: corn germ, cottonseed, flax, peanut, rapeseed (for example, canola)...
• Oilseed CropPrimarily soybeans, and other crops such as peanuts, cottonseed, sunflower seed, flaxseed, safflower seed...
• Oilseed Solvent Loss FactorRatio expressed as gallons of solvent loss per ton of oilseed processed. The solvent loss factors are...
• Oil/Water Separation (API Separator, Skimming)Removal of gross quantities of oil and suspended solids by skimming and collecting oil from the surface of...
• Oil/Water Separation, OtherRemoval of oil and suspended solids by a process not classified as an API separator, as skimming, or as a...
• Oil-Water Separator1. Wastewater treatment equipment used to separate oil from water consisting of a separation tank, which also...
• Oily Absorbent RecyclingProcess of recycling oil-soaked or contaminated disposable rags, paper, or pads for the purpose of...
• Oily OperationOne or more of the following: abrasive blasting; adhesive bonding; alkaline cleaning for oil removal...
• Oily WasteWastes and/or used materials that contain oil and grease (generally at or in excess of 100 mg/L) from...
• Oily WastewaterWastewater generated during the refinery process which contains oil, emulsified oil, or other hydrocarbons...
• Ointment BaseVarious mixtures of fats, waxes, animal and plant oils and solid and liquid hydrocarbons; vehicles for...
• Oklahoma Tribal Statistical Areas Joint-Use AreasAs applied to OTSAs by the Census Bureau...
• Old Chemical Registration ReviewReview of an application for registration of a new product containing active ingredients and uses which are...
• Old Corrugated ContainersRefers to corrugated containers made from unbleached, unwaxed paper with a ruffled (corrugated) inner liner...
• Old EPA Basin CodeA concatenation of the two digit EPA Major Basin Code, the two digit EPA Minor Basin Code, and the two digit...
• Old MagazinesRefers to dry, coated magazines, catalogues, and similar printed materials. (Institute of Scrap Recycling...
• Old NewspaperRefers to periodicals printed on newsprint. Includes groundwood inserts (advertisements). Examples of...
• Older adultsIn many studies, older adults are defined as ages 65 years and older due to age definitions provided in...
• Oleaginous FungusFungus that produces lipids sufficient to be harvested as a biofuel
• Olfactory Fatigue(oh-FAK-tore-ee) A condition in which a person's nose, after exposure to certain odors, is no longer able to...
• Oligohaline1. Brackish waters with low salinities that range from 0.5 to 5 parts per thousand (ppt).
• Oligohaline WaterBrackish waters with low salinities that range from 0.5 to 5 parts per thousand (ppt).
• Oligomer1. Polymer molecule consisting of only a few monomer units (dimer, trimer, tetramer)
• Oligonucleotides1. A short segment of single stranded nucleic acid or a short sequence of nucleotides (e.g., PCR primers and...
• OligosaccharidesCarbohydrates consisting of between two (disaccharies) and ten monosaccharides connected by either an alpha-...
• Oligotrophic1. (AH-lig-o-TRO-flck) Reservoirs and lakes which are nutrient poor and contain little aquatic plant or...
• Oligotrophic LakeDeep lakes that have a low supply of nutrients and thus contain little organic matter. Such lakes are...
• Oligotrophic Lakes1. Deep lakes that have a low supply of nutrients and thus contain little organic matter. Such lakes are...
• Oligotrophic Water BodyA water body or habitat with low concentrations of nutrients.
• OliguriaSecretion of a diminished amount of urine in relation to fluid intake
• Olive ProcessingProcessing of olives into the following product styles: Canned, all varieties, fresh and stored, green ripe...
• O&M PlanOperation and maintenance plan developed by Astaris-Idaho and submitted to EPA in accordance with paragraph...
• OMB CIRCULAR NO. A-130, MANAGEMENT OF FEDERAL INFORMATION RESOURCESA policy statement issued by the Office of Management and Budget regarding the management of Federal...
• OmbudsmanAn appointee within each of EPA's ten Regions who serves as a direct point of contact for the public on...
• OmeprazoleA 4-methoxy-3,5-dimethylpyridyl, 5-methoxybenzimidazole derivative of timoprazole that is used in the therapy...
• Omics1. Refers to a broad field of study in biology, ending in the suffix "-omics" such as genomics, proteomics...
• Omnibus ProvisionThe authority which allows EPA to add conditions to a TSDF permit that are not specifically addressed by the...
• OmnivoreAn organism that will eat both plants and animals.
• OmnivorousAn omnivorous animal is one that eats both plants and other animals.
• omnivorous fishFish, such as carp, that eat both plants and animals and are tolerant of poor water conditions.
• OMSAPC(in 68-W3-0030 contract)
• On Board Aerospace Fire SuppressionUse of a regulated substance in fire suppression equipment used on board commercial and general aviation...
• On Ground TankDevice meeting the definition of “tank” in § 260.10 and that is situated in such a way that the bottom of the...
• On Scene CoordinatorsThe federal official responsible for the coordination of a hazardous materials response action, as specified...
• on siteOn the same, or adjacent, property.
• Onboard ChargerTakes the incoming AC electricity supplied via the charge port and converts it to DC power for charging the...
• Onboard ControlsDevices placed on vehicles to capture gasoline vapor during refueling and route it to the engines when the...
• Onboard Diagnostics GroupCombination of engines, engine families, or engine ratings that use the same OBD strategies and similar...
• On-Board Emissions MonitorContinuously measures the concentration of various gaseous components of vehicles.
• Once-Through Cooling Water1. Water passed through the main cooling condensers in one or two passes for the purpose of removing waste...
• Once-Through Cooling Water SystemSystem designed to withdraw water from a natural or other water source, use it at the facility to support...
• Oncogene1. A gene that normally directs cell growth. If altered, an oncogene can promote or allow the uncontrolled...
• Oncogene Activation ProcessAny DNA sequence alteration process occurring in a proto-oncogene, resulting in loss of regulation of the...
• OncogenicResulting from a gene that can induce neoplastic transformations in the cell in which it occurs or into which...
• OncoLogicComputer software program developed by EPA's Office of Chemical Safety and Pollution Prevention designed to...
• OncologyStudy of cancer.
• OnconogenicityThe capacity to induce cancer.
• OncosisA cellular process characteristic of necrotic cell death, resulting in swelling of the cell body.
• On-demand hot water systemsTankless or instantaneous water heaters that provide hot water only as it is needed. On-demand water heaters...
• On-Demand Self-ServiceA consumer can unilaterally provision computing capabilities, such as server time and network storage, as...
• On-dock RailyardA railyard connected directly to a dock.
• One and Two-Piece Draw and Iron CanSteel or aluminum can manufactured by the draw and iron process. Includes two-piece beverage cans, two-piece...
• One call systemCentralized and integrated phone-based system for obtaining information from a single phone call on...
• One Day MaximumApplied to BPT, BCT and BAT effluent limitations and NSPS for oil and grease in produced water means the...
• One Hit ModelA dose-response model based on a mechanistic argument that there is a response after a target site has been...
• One Record per LineA type of emissions inventory format used as input to SMOKE that has one record / pollutant per line instead...
• One-Dimensional ModelA mathematical model defined along one spatial coordinate of a natural water system. Typically 1-D models are...
• One-Dimensional Monte Carlo AnalysisA method of simulating a distribution for an endpoint of concern as a function of probability distributions...
• One-group DesignsResearch designs which study a single program with no comparison or control group.
• One-Minute AverageAverage of detector responses calculated at least every 60 seconds from responses obtained at least every 15...
• One-Piece Aerosol CanAerosol can formed by the draw and iron process to which no ends are attached and a valve is placed directly...
• One-shot Case StudyThe one-shot case study involves the measurement of an identified "outcome" after a treatment or program has...
• One-Sided Confidence IntervalInterval below the estimated upper confidence limit, or interval above the estimated lower confidence limit...
• One-Time Expansion Device1. An appliance that relies on the one-time release of its refrigerant charge to the environment in order to...
• One-Way ValveValve that is designed and constructed to allow virtually unrestricted flow in one direction and no flow in...
• On-frame dataData acquired by a sampling approach that provides a probability sample.
• Ongoing Precision and Recovery Standard1. A method blank spiked with known quantities of analytes. Its purpose is to assure that the results...
• Onion Yellows(Phytoplasma infection of onions.) Symptoms that are characteristic of diseases caused by phytoplasmas...
• ON-LINEUnder the direct control of a computer. Refers to data on a medium, usually a disk, directly accessible for...
• Online AttackAn attack against an authentication protocol where the Attacker either assumes the role of a Claimant with a...
• Online Decision ToolWeb-based tool for information gathering that supports decision making for a specific purpose, such as health...
• Online MonitoringAn automated means for recording the emission or parameter being measured, detected, or analyzed.
• On/Off ReachFlag indicating if a station is on an indexed search.
• Onopordum acanthiumCrowds out native species and crops.
• On-Road Mobile Source1. Mobile sources used on roads and highways for transportation of passengers or freight. On-road sources...
• Onroad Mobile SourceAny mobile source of air pollution such as cars, trucks, motorcycles, and buses that travels on roads and...
• Onroad Mobile Source EmissionsEmission from any mobile source of air pollution such as cars, trucks, motorcycles, and buses that travels on...
• On-road Mobile SourcesMobile sources used on roads and highways for transportation of passengers or freight. On-road sources...
• On-Road Motor Vehicle EmissionEmission from vehicles that are meant to travel safely on roads and highways
• On-Road Pollution Source EmissionEmission from a vehicle which is designed to be safely drive on roads and highways
• Onroad sourcesVehicles used on roads for transportation of passengers or freight, also called "on-highway."
• On-Scene Coordinator1. The federal official responsible for the coordination of a hazardous materials response action, as...
• Onshore Area1. Coastal area designated as an attainment, nonattainment, or unclassifiable area by EPA in accordance with...
• Onshore Facility1. As defined by section 311(a)(10) of the CWA, means any facility (including, but not limited to, motor...
• Onshore Land1. All land areas landward of the inner boundary of the territorial seas as defined in 40 CFR 125.1(gg).
• Onshore Natural Gas Production FacilityFor purposes of reporting under this subpart and for the corresponding subpart A requirements means all...
• Onshore Oil Storage FacilityAny facility (excluding motor vehicles and rolling stock) of any kind located in, on, or under, any land...
• Onshore Petroleum and Natural Gas Production OperatorPerson or entity who holds the permit to operate petroleum and natural gas wells on the drilling permit or an...
• Onshore Petroleum and Natural Gas Production OwnerPerson or entity who holds the permit to operate petroleum and natural gas wells on the drilling permit or an...
• Onshore Petroleum Production FacilityFor purposes of reporting under this subpart and for the corresponding subpart A requirements means all...
• Onsite Coating Mix Preparation EquipmentPieces of coating mix preparation equipment located at the same plant as the coating operation they serve.
• Onsite Collected WaterWater sources generated within or surrounding a building, residence, or district. Other terms referring to...
• Onsite collected watersWater sources generated within or surrounding a building, residence, or district. Other terms referring to...
• On-Site Compliance Paperwork1. Data or information retained in the offices of the facility which supports the initial and periodic...
• On-Site Facility1. A hazardous waste treatment, storage or disposal area that is located on the generating site.
• Onsite non-potable water reuse1. The use of treated onsite collected waters for non-potable purposes at the single-building or district...
• On-Site Record Storage1. With respect to records required to be maintained by this subpart or required by another subpart...
• Onsite Record Storage1. With respect to records required to be maintained by this subpart or required by another subpart...
• Onsite Release to the EnvironmentOn-site releases to the environment include emissions to the air, discharges to surface waters, and releases...
• Onsite Releases to the EnvironmentOn-site releases to the environment include emissions to the air, discharges to surface waters, and releases...
• On-Site Renewable Electricity GenerationElectricity generated by renewable resources using a system or device located at the site where the power is...
• Onsite Renewable Energy GenerationElectricity generated by renewable resources using a system or device located at the site where the power is...
• On-Site Renewable GenerationElectricity generated by renewable resources using a system or device located at the site where the power is...
• Onsite Service ProviderA person who provides onsite system services. Providers include (but are not limited to) designers...
• On-Site SystemA wastewater treatment system relying on natural processes or mechanical components or both to collect and...
• Onsite Wastewater Treatment SystemA system relying on natural processes and/or mechanical components to collect, treat, and disperse or reclaim...
• On-Specification Lime ProductLime product that has been sufficiently calcined to meet end use requirements.
• On-Specification Used OilUsed oil that meets all the given parameters for arsenic, cadmium, chromium, flash point, lead, and total...
• OntologyAn ontology is a controlled vocabulary that seeks to show how certain terms are related to one another.
• OosporaOne of the most common molds most often found on meat and poultry.
• OosporeA thick-walled spore which develops from an oospherc through either fertilization or parthenogenesis
• Opacity1. The amount of light obscured by particulate pollution in the air; clear window glass has zero opacity, a...
• Opacity Action LevelLevel of opacity of emissions from a source requiring the owner or operator of the Astaris-Idaho facility to...
• Opacity Emission Standard and Control MeasureNo owner or operator shall discharge or cause the discharge of emissions from the stacks of Units 4 and 5...
• Opaque CoatingNot allowing light to pass through, so that the substrate is concealed from view.
• OPCumRiskA computer program developed at ORD's NHEERL to determine relative potency estimates and PoDs for the index...
• Open BarnOpen spaced shelter in which cattle are free to move about or rest wherever they might prefer, usually on a...
• Open BarnsOpen spaced shelter in which cattle are free to move about or rest wherever they might prefer, usually on a...
• Open Biological Treatment ProcessBiological treatment process that is not a closed biological treatment process as defined in this section...
• Open Burning1. Uncontrolled fires in an open dump.
• Open Channel FlowFluid flow where the bottom and sides of the flow are confined by solid surfaces and the upper surface is in...
• Open Circulatory SystemA circulatory system, characteristic of some invertebrates, e.g., arthropods, in which blood flows through an...
• Open CombustionBasic oxygen furnace steelmaking wet air cleaning systems which are designed to allow excess air to enter the...
• Open Crankcase EmissionsAny flow from an engine's crankcase that is emitted directly into the environment. Crankcase emissions are...
• Open Cut MineAny form of recovery of ore from the earth except by a dredge.
• Open CycleThese systems use the tropical oceans' warm surface water to make electricity. When warm seawater is placed...
• Open Dump1. An uncovered site used for disposal of waste without environmental controls.
• Open DumpsSolid waste disposal facilities that fail to comply with the Subtitle D criteria.
• Open Dumps InventoryInventory required under section 4005(b) and is defined as the list published by EPA of those disposal...
• Open holeUncased intervals of a drill hole.
• Open Path AnalyzerAutomated analytical method that measures the average atmospheric pollutant concentration in situ along one...
• Open Path Analyzer Monitoring PathActual path in space between two geographical locations over which the pollutant concentration is measured...
• Open Path Analyzer Monitoring Path LengthLength of the monitoring path in the atmosphere over which the average pollutant concentration measurement...
• Open PitPit which is any mine, quarry, or excavation area worked by the open-cut method to obtain material of value.
• Open Pit MiningA form of operation designed to extract minerals that lie near the surface. Waste, or overburden, is first...
• Open SiteArea that is essentially free of large sound-reflecting objects, such as barriers, walls, board fences...
• Open spaceAn area of land that is valued for natural processes and wildlife, agricultural and sylvan production, active...
• Open Space PlanA plan that identifies needs and actions to develop and/or protect areas for recreation, green spaces, such...
• Open Storage PileAny facility, including storage area, that is not enclosed that is used to store coal, including the...
• Open Submerged Arc FurnaceElectric submerged arc furnace that is equipped with a canopy hood above the furnace to collect primary...
• Open Surface Hard Chromium Electroplating TankChromium electroplating tank that is ventilated at a rate consistent with good ventilation practices for open...
• Open SystemThis means that energy or mass can move into or out of the system.
• Open URL LinkingWhen link resolvers automatically direct users to a URL where they can access their library's holdings when...
• Open Waters of the Great LakesAll of the waters within Lake Erie, Lake Huron (including Lake St. Clair), Lake Michigan, Lake Ontario, and...
• Open-Access GoodsGoods which become rival in consumption and nonexclusive.
• Open-Access Journal ArticleArticle that publishers allow free, unrestricted online public access to, without the need for a...
• Open-Access Journal ArticlesAn article that publishers allow free, unrestricted online public access to, without the need for a...
• Open-Cut MiningA form of operation designed to extract minerals that lie near the surface. Waste, or overburden, is first...
• Open-ended InterviewAn interview in which, after an initial or lead question, subsequent questions are determined by topics...
• Open-Ended ValveAny valve, except safety relief valves, having one side of the valve seat in contact with process fluid and...
• OpeningAny service, maintenance, or repair on an appliance that would release Class I or Class II refrigerant from...
• Opening an Appliance1. Any service, maintenance, repair, or disposal of an appliance that would release refrigerant from the...
• Open-Loop Geothermal Heat Pump SystemOpen-loop (also known as "direct") systems circulate water drawn from a ground or surface water source. Once...
• Open-Loop Recycling1. A recycling process in which materials from old products are made into new products in a manner that...
• OpennessThe ethical obligation to share the results of scientific research, including data and methods. [NIH National...
• Open-pit Uranium MiningThe mining process that involves stripping away or excavating the topsoil and rock that lie above the uranium...
• Open-Top CupolaCupola that is open to the outside air and operates with an air flow rate that is unrestricted and at low...
• Open-Top Vapor Cleaning MachineBatch solvent cleaning machine that has its upper surface open to the air and boils solvent to create solvent...
• Operable ControlsA component of a product that requires physical contact for normal operation. Operable controls include, but...
• Operable Unit1. Term for each of a number of separate activities undertaken as part of a Superfund site cleanup. A typical...
• Operant ConditioningA learning process where an animal learns by connecting its own behavior with a response from its environment.
• Operating and Maintenance CostThe costs associated with operation and maintenance of a control measure. These costs are annual and...
• Operating AreaRivers and Canals, Inland, Nearshore, and Great Lakes geographic location(s) in which a facility is handling...
• Operating Basis EarthquakeThe earthquakes for which the structure is designed to resist and remain operational. It reflects the level...
• Operating Combustion Source1. With regard to a unit under §§ 97.22(d)(2) and 97.80, having documented heat input for more than 876 hours...
• Operating ConditionsConditions specified in a RCRA permit that dictate how an incinerator must operate as it burns different...
• Operating costsRecurring expenditures associated with the operation and maintenance of equipment, including salaries and...
• Operating ExpensesTotal annual cost of operating and maintaining the water or wastewater utility service. This does not include...
• Operating ImpoundmentAn impoundment is being used for the continued placement of uranium byproduct material or tailings or is in...
• Operating MannerThe manner in which a model operates. Models can be designed to represent phenomena in different modes...
• Operating Parameter Value1. Minimum or maximum value established for a control device or process parameter that, if achieved by itself...
• Operating Permit1. A renewable and revocable permit to operate and maintain an onsite or clustered treatment system in...
• Operating port1. A port where the port authority builds the wharves, owns the cranes and cargo-handling equipment, and...
• Operating PressureContainment pressure that characterizes the normal state of gas or liquid inside a particular process...
• Operating Process Source1. When referring to a combustion or process source seeking entry into the Opt-in Program, means that the...
• Operating Ratio1. Operating Ratio = Operating Revenue / Operating Expense
• Operating RecordDocumentation retained at the facility for ready inspection by authorized officials of all information...
• Operating RequirementOperating terms or conditions, limits, or operating parameter limits developed under this subpart that ensure...
• Operating RequirementsParameters established by a facility and written into a permit that will ensure a combustion unit meets...
• Operating Scenario1. For the purposes of reporting and recordkeeping, a description of a PAI process unit, including...
• Operating SourceEngaged in activity related to the primary design function of the source.
• Operating status1. The conditions under which the facility site or the emissions unit was operating during the time emissions...
• OPERATING SYSTEMIn electronic records, software directing a computer's operation.
• Operating VoltageThe voltage level by which an electrical system is designated and to which certain operating characteristics...
• Operating VolumeThe volume of the lagoon needed to hold and treat the manure influent and the rain-evap volume.
• Operation and Maintenance1. Activities conducted after a Superfund site action is completed to ensure that the action is effective.
• Operation and Maintenance CostsThe ongoing, repetitive costs of operating a water system; for example, employee wages and costs for...
• Operation and Maintenance PlanOperation and maintenance plan developed by Astaris-Idaho and submitted to EPA in accordance with paragraph...
• Operational & FunctionalThe point in time that EPA declares the remedy associated with a site is functioning properly and is...
• Operational ChangeFor purposes of § 98.3(b), a change in the type of feedstock or fuel used, a change in operating hours, or a...
• Operational ControlsBroadly defined to include engineering (e.g., water reclamation tanks), physical (e.g., dikes and berms), and...
• Operational Cost1. Refer to costs incurred during the operating lives of processes, products, systems, and facilities, as...
• Operational DefinitionDetailed description of how a concept or variable will be measured and how values will be assigned.
• Operational MeasureModification to any operation at a facility that serves to minimize impact to fish and shellfish from the...
• Operational PlanA tactical statement of when and what critical milestones must be passed to attain objectives programmed for...
• OperationalizeTo define a concept in a way that can be measured. In evaluation research, to translate program inputs...
• operations1. All activities and facilities involved in management, access, exploration, extraction, beneficiation...
• Operations and Maintenance1. The activities related to the performance of routine, preventive, predictive, scheduled, and unscheduled...
• Operations and maintenance program1. A program of work practices to maintain friable ACBM in good condition, ensures cleanup of asbestos fibers...
• operations managerThe Operations Manager is independent of the QAM. In some organizations this individual may also be referred...
• OperativeMost jobs in this category include intermediate skilled occupations and include workers who operate machines...
• Operator1. The owner or operator of any facility or activity subject to the UIC regulations.
• Operator CertificationCertification of operators of community and nontransient noncommunity water systems, asbestos specialists...
• Operator Demand1. Meaning given in 40 CFR 1065.1001.
• Operator Service ProviderA common carrier that provides services from public phones, including payphones and those in hotels/motels.
• Operator/OwnerFor the purpose of the 2003 Construction General Permit and in the context of stormwater associated with...
• Operculum1. A lid or flap covering an aperture, such as the gill cover in most bony fishes; the gill cover; also the...
• OphthalmicPertaining to the eye
• OpinionA time-bound judgment or speculation that fluctuates unpredictably. In contrast to beliefs (i.e., tenaciously...
• Opioid Receptor BindingA process that involves the non-covalent binding of opioids to one of four opioid receptors. These...
• OpportunisticAble to exploit newly available habitats or resources.
• Opportunistic FeederA species adapted for utilizing variable, unpredictable or transient environments to obtain food.
• Opportunistic InfectionsInfection caused by an organism which is capable of causing disease in immunocompromised patients only...
• Opportunistic Microorganism1. Refers to potential to cause adverse human outcomes under certain environmental and health conditions...
• opportunity cost1. The value of a foregone opportunity that cannot be pursued because resources are taken up by a chosen...
• Opportunity Costs1. The value of opportunities forgone because of an intervention program.
• Optical Anti-Reflection CoatingCoating with a low reflectance in the infrared and visible wavelength ranges, which is used for...
• OPTICAL CHARACTER RECOGNITIONA method of entering data into a computer by using an optical scanning device to read the contents of...
• Optical Density (Of The Atmosphere)The optical density of a material relates to the tendency of its atoms to retain the absorbed energy of an...
• Optical DiscCompact disc (CD) or digital video disc (DVD).
• OPTICAL DISKA noncontact, random-access disk typically tracked by optical laser beams and used for mass storage and...
• Optical Gas ImagingDifferent ways of setting up an optical gas imaging (OGI) camera that affect its detection capability...
• Optical Gas Imaging CameraField portable instrumentation that makes visible emissions that may otherwise be invisible to the naked eye.
• Optical Gas Imaging Camera OperatorSomeone who has completed the training required in Section 10 and passed the final survey test in Section...
• Optical Open-Path MonitorUsed to evaluate emissions or ambient levels of volatile organic or inorganic chemicals. These monitors rely...
• Optically Detected Magnetic ResonanceImaging method in which the usual magnetic resonance signal is transferred to optical frequencies to enhance...
• Optimal Corrosion Control Treatment1. The corrosion control treatment that minimizes the lead and copper concentrations at users' taps while...
• Optimal DecisionThe decision regarding a problem which leads to the best/most favorable result.
• Optimum offsetSeismic reflection technique employing optimum window.
• Optimum value engineeringLumber layout and usage techniques that minimize the amount of lumber used to construct a house without...
• Opt-in AreaArea which becomes a covered area under §80.70 pursuant to section 211(k)(6) of the Clean Air Act.
• Opt-in PermitLegally binding written document that is contained within the Acid Rain permit and sets forth the...
• Opt-in SourceCombustion source or process source that has elected to become an affected unit under the Acid Rain Program...
• Opt-In Source Replacement UnitAffected unit replacing the thermal energy provided by an opt-in source, where both the affected unit and the...
• OptionUnilateral right in a contract by which, for a specified time, the Government may elect to purchase...
• Option Value1. Value to know something will exist for use in the future.
• OPTIONAL FORMA form developed by a Federal agency for use by two or more agencies and approved by GSA for nonmandatory use...
• OPTIONAL FORM 11, REFERENCE REQUEST--FEDERAL RECORDS CENTERSA form that an agency may use to obtain reference service involving records it has stored in a Federal...
• OralOf the mouth; through or by the mouth.
• Oral Cancer Slope FactorAn upper bound, approximating a 95% confidence limit, on the increased cancer risk from a lifetime exposure...
• Oral Cavity1. The cavity located at the upper end of the alimentary canal, behind the teeth and gums that is bounded on...
• Oral Cleft DefectsAn abnormal opening in a structure around the mouth and face. Clefts may occur in the lip, the roof of the...
• ORAL HISTORY MATERIALSAll documents, regardless of media, relating to interviews conducted expressly for historical purposes by, or...
• Oral Reference DoseAn estimate (with uncertainty spanning perhaps an order of magnitude) of a daily oral exposure of a chemical...
• Oral Slope Factor1. An upper bound, approximating a 95% confidence limit, on the increased cancer risk from a lifetime oral...
• Oral ToxicityAbility of a pesticide to cause injury when ingested.
• Orbital ForcingTheory that proposes large scale climate changes are due in part to the variations in precession...
• ORCID IDPersistent digital identifier attached to a researcher's name that elimniates the chance that similar names...
• Order1. Any order issued by the Administrator under section 309 of the Act; any order issued by a State to secure...
• Order BiasA skewing of results caused by the order in which questions are placed in a survey.
• Order (Generic)Action used to describe any combination of specific enforcement related orders.

859 of 30,736 terms in Environment terminology (MLC-0121). Request the full dataset.