Glossary of Terms


A   B   C   D   E   F   G   H   I        L   M   N
O   P      R   S   T   U   V      X  

  A   

Acetone:  see PDF

Active: A site is designated as active when the person or business located at the site is generating and/or handling regulated waste subject to hazardous waste, universal waste, or used oil management regulations under the Montana Hazardous Waste Act.

Acute hazardous waste-Extremely dangerous hazardous waste:  Typically these have a "P" waste code and are listed in 40 CFR 261.33. Generators who generate or accumulate more than 2.2 pounds of acute hazardous waste are subject to increased regulation.

Aerate:  Adding air or oxygen.

Air Sparge:  Injecting air or oxygen into groundwater to strip or flush volatile contaminants up through the groundwater as air bubbles and capture them with a vapor extraction system.

Alternate Concentration Limit (ACL):  see PDF

Anthracene:  see PDF

Aquifer:  An underground geological formation, or group of formations, containing water. Are sources of groundwater for wells and springs.

Area of Concern (AOC):  A term used in conjunction with facility-wide corrective action at hazardous waste management facilities. Any area at a facility having a probable release of a hazardous waste or hazardous constituent which may or may not be from a solid waste management unit (SWMU) and is determined by the Department of Environmental Quality to pose a current or potential threat to human health or the environment. AOCs include areas that have been contaminated by routine and systematic releases of hazardous waste or hazardous constituents, excluding one-time accidental spills that are immediately remediated and cannot be linked to solid waste management activities. AOCs are considered equivalent to SWMUs for the purposes of facility-wide corrective action.

Arsenic:  see PDF

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  B   

Benzene:  see PDF

Beryllium:  see PDF

Bioremediation:  Any process that uses microorganisms, fungi, green plants or their enzymes to return the natural environment altered by contaminants to its original condition.

BTEX:  Acronym for Benzene, Toluene, Ethylbenzene, and Xylene.

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  C   

Carcinogen:  A cancer-causing agent.

Cathode Ray Tube (CRT):  A vacuum tube, composed primarily of glass, which is the visual or video display component of an electronic device. A used, intact CRT means a CRT whose vacuum has not been released. A used, broken CRT means glass removed from its housing or casing whose vacuum has been released.

Chlorinated Hydrocarbons:  Chemical compounds containing hydrogen, carbon, oxygen, and chlorine.

Chrysene:  see PDF

Closed:  A site is designated as closed when the business located at the site is out of operation and regulated wastes subject to hazardous waste, universal waste, or used oil management regulations under the Montana Hazardous Waste Act are no longer generated and/or handled.  This is a Montana-specific classification.

Commercial Hazardous Waste Transfer Facility:  A transfer facility owned or operated by a commercial for-hire transporter and in which the major purpose of the commercial transfer facility is the collection, storage, and transfer of hazardous waste; that is, over 50% of the materials moved through the commercial transfer facility are hazardous wastes, or greater than 100 tons of material moved through the commercial transfer facility are hazardous waste.

Conditionally Exempt Small Quantity Generator:  A hazardous waste generator who never generates more than 220 pounds of non-acute hazardous waste or 2.2 pounds of acute hazardous waste in any month. They may not accumulate more than 2.2 pounds of acute hazardous waste at any time.

Controlled Groundwater Use Area:  An area that has additional management controls applied to groundwater. The new controls may prohibit further well drilling or groundwater use. The controlled groundwater area is pursuant to regulations in Montana Code Annotated, 85-2-506 through 85-2-508.

Corrective Action Management Unit (CAMU):  Physically distinct geographic areas within a facility designated for managing remediation wastes generated by corrective action or cleanup at the facility. CAMU rules are set forth in 40 CFR 264.552, as incorporated by reference in the Administrative Rules of Montana (ARM) 17.53.801.

Corrective Action Process:  The corrective action process generally comprises six activities. These activities are not always undertaken as a linear progression towards final facility cleanup, but can be implemented flexibly to most effectively meet site-specific corrective action needs.

Corrective Measures Implementation (CMI):  Once a remedy has been selected, the facility enters the CMI phase of corrective action. During the CMI, the owner/operator of the facility implements the chosen remedy.

Corrective Measures Study (CMS):  The purpose of the CMS is to identify and evaluate cleanup alternatives, called corrective measures, for releases at the facility. The recommended measures are reviewed by the regulatory agency.

Corrosive Waste:  see 40 CFR 261.22

Creosote:  see PDF

Cross Gradient:  Perpendicular to the direction that groundwater flows; similar to "cross stream" for surface water.

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  D   

Dense Non-Aqueous Phase Liquid (DNAPL):  Non-aqueous phase liquids such as chlorinated hydrocarbon solvents or petroleum fractions with a specific gravity greater than 1.0 that sink through the water column until they reach a confining layer.  Because they are at the bottom of aquifers instead of floating on the water table, typical monitoring wells do not indicate their presence.

Dichlorophenoxyacetic Acid (2,4-D):  see PDF

Down Gradient:  The direction that groundwater flows; similar to "downstream" for surface water.

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  E   

Ecological Risk Assessment:  The application of a formalframework, analytical process, or model to estimate the effects of human actions(s) on a natural resource and to interpret the significance of those effects in light of the uncertainties identified in each component of the assessment process. Such analysis includes initial hazard identification, exposure and dose-response assessments, and risk characterization.

Electronic Waste (E-waste):  E-waste includes a wide variety of items such as: cell phones, computers, keyboards, and printers. Many of these items include small bits and pieces of heavy metals. Those metals may cause the e-waste to be regulated as hazardous waste if the items are disposed.

Environmental Indicator:  A measurement, statistic or value that provides an approximate gauge or evidence of the effects of environmental management programs or of the state or condition of the environment.

Ethylbenzene:  see PDF

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  F   

Flocculation:  Process by which clumps of solids in water or sewage aggregate through biological or chemical action so they can be separated from water or sewage.

Fly Ash:  Non-combustible residual particles expelled by flue gas.

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  G   

Groundwater:  The supply of fresh water found beneath the Earth's surface, usually in aquifers, which supply wells and springs. Because ground water is a major source of drinking water, there is growing concern over contamination from leaching agricultural or industrial pollutants or leaking underground storage tanks.

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  H   

Halogenated Solvent:  Often referred to a chlorinated solvent. All these solvents contain chlorine as part of the solvent make-up (not as part of the propellant). Examples are: Methylene Chloride, Trichloroethylene, Perchloroethylene.

Halogenated Solvent User:  Anyone who sells, buys, or uses more than 20 gallons of halogenated solvent in any year must register as a Halogenated Solvent User.  A registration form must be completed and submitted to the Montana Department of Environmental Quality.  There is no registration fee.  For more information about halogenated solvents, click on Halogenated Solvents Users Registration Act.

Hazardous and Solid Waste Amendments of 1984 (HSWA):  Amendments to RCRA, enacted in 1984. The HSWA amendments include the requirement that all facilities permitted under RCRA must address releases of hazardous constituents on a facility-wide basis.

Hazardous Waste Generator:  Any person, by site, whose act or process produces hazardous waste identified or listed in 40 CFR 261.

Hazardous Waste Management Facility (HWMF):  HWMF means all contiguous land and structures, other appurtenances, and improvements on the land used for treating, storing, or disposing of hazardous waste. A facility may consist of several treatment, storage, or disposal operational units.

Hazardous Waste Permit:  A negotiated document which allows for the treatment, storage, and/or disposal of hazardous waste under very strict conditions.

Hazardous Waste Transfer Facility:  Any transportation-related facility, including loading docks, parking areas, storage areas, and other similar areas where shipments of hazardous waste are held during the normal course of business. The waste may not be held for more than 10 days at a transfer facility.

Hazardous Waste Transporter:  A person engaged in the off-site transportation of hazardous waste by air, rail, highway, or water.

Herbicide:  A chemical pesticide designed to control or destroy plants, weeds, or grasses.

Human Health Risk:  The likelihood that a given exposure or series of exposures may have damaged or will damage the health of individuals.

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  I   

Ignitable Waste:  see 40 CFR 261.21

In-situ:  In place.

Inactive:  A site is designated as inactive when the business located at the site is not generating and/or handling regulated waste subject to hazardous waste, universal waste, or used oil management regulations under the Montana Hazardous Waste Act.  This is a Montana-specific classification.

Inorganics:  Chemical compounds that do not contain Hydrogen, Oxygen and Carbon.

Institutional Controls:  Non-engineered instruments, such as administrative and legal controls, that help minimize the potential for human exposure to contamination and/or protect the integrity of the remedy.

Interim Measures (IM):  Short-term actions taken to mitigate the actual release or the threat of a potential release of hazardous waste or hazardous waste constituents from a facility. Generally, interim measures are conducted while developing a long-term comprehensive corrective action strategy.

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  J   

  K   

  L   

Land Treatment Unit (LTU):  A disposal area in which hazardous waste deposited on or in the soil is degraded naturally by microbes.

Large Quantity Generator:  Person or facility generating more than 2200 pounds of non-acute hazardous waste or 2.2 pounds of acute hazardous waste in any month, or who accumulate more than 2.2 pounds of acute hazardous waste.

Large Quantity Handler of Universal Waste (LQHUW):  Receives UW from other handlers and sends it to other UW facilities, and accumulates more than 5,000 kilograms of UW at any time.

Lead:  see PDF

Light Non-Aqueous Phase Liquid (LNAPL):  A non-aqueous phase liquid with a specific gravity less than 1.0.  Because the specific gravity of water is 1.0, most LNAPLs float on top of the water table. Most common petroleum hydrocarbon fuels and lubricating oils are LNAPLs.

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  M   

Mercury:  see PDF

2-Methyl-4-Chlorophenoxyacetic Acid (MCPA):  see PDF

2-(2-Methyl-4-Chlorophenoxy)Propionic Acid (MCPP):  see PDF

Methylene Chloride:  see PDF

Methyl Ethyl Ketone (MEK):  see PDF

Monitored Natural Attenuation:  Reliance on natural attenuation processes (within the context of a carefully controlled and monitored site cleanup approach) to achieve site-specific remediation objectives within a time frame that is reasonable compared to that offered by other more active methods. The 'natural attenuation processes' that are at work in such a remediation approach include a variety of physical, chemical, or biological processes that, under favorable conditions, act without human intervention to reduce the mass, toxicity, mobility, volume, or concentration of contaminants in soil or groundwater.

Montana Hazardous Waste Act (MHWA):  Montana statute that allows MT DEQ to adopt, administer, and enforce the state’s hazardous waste program pursuant to federal Resource Conservation and Recovery Act.

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  N   

Napthalene:  see PDF

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  O   

Organic:  1. Referring to or derived from living organisms.  2. In chemistry, any compound containing carbon, hydrogen, and oxygen.

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  P   

Perchloroethylene (see Tetrachloroethylene):  see PDF

Phenanthrene:  see PDF

Phenols:  see PDF

Phytoremediation:  The treatment of environmental problems through the use of plants which mitigate the environmental problem.

Polycyclic Aromatic Hydrocarbons (PAHs):  Chemical compounds that are formed by incomplete combustion of carbon-containing fuels such as wood, coal, diesel, fat, or tobacco. Many of them are known or suspected carcinogens. see PDF

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  Q   

  R   

Resource Conservation and Recovery Act (RCRA):  A federal law intended to protect human health and the environment from the potential hazards of waste disposal, conserve energy and natural resources, reduce the amount of waste generated, and ensure that wastes are managed in an environmentally sound manner.

RCRA Facility Assessment (RFA):  The objective of the RFA is to identify potential and actual releases from SWMUs/AOCs and make preliminary determinations about releases, the need for corrective action, and interim measures.

RCRA Facility Investigation (RFI):  The RFI takes place when releases, or potential releases, have been identified and further investigation is necessary. The purpose of the RFI is to gather enough data to fully characterize the nature, extent, and rate of migration of contaminants to determine the appropriate response action.

Reactive Waste:  see 40 CFR 261.23

Risk Assessment:  Qualitative and quantitative evaluation of the risk posed to human health and/or the environment by the actual or potential presence and/or use of specific pollutants

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  S   

Saline Seep:  An expanse of salt crystals forming when underground salty water reaches the soil surface and evaporates.

Sedimentation:  The action or process of depositing sedimentation that is suspended in a liquid.

Semi-volatiles:  Any organic compounds which have a boiling point higher than water and which may vaporize when exposed to temperatures above room temperature. Semi-volatile organic compounds include phenols and polynuclear aromatic hydrocarbons (PAH).

Small Quantity Generator:  Persons or enterprises that produce 220-2200 pounds per month of non-acute hazardous waste.

Small Quantity Handler of Universal Waste (SQHUW):  Receives UW from other handlers and sends it to other UW facilities, and never accumulates more than 5,000 kilograms of UW at any time.

Solid Waste Management Unit (SWMU):  A term used in conjunction with facility-wide corrective action at hazardous waste management facilities. Any discernible unit at which solid waste has been placed at any time, irrespective of whether the unit was intended for the management of solid or hazardous waste. Such units include any area at a facility at which solid wastes have been routinely and systematically released.

Specification Used Oil:  Used oil that has been proven to meet the specifications set forth in 40 CFR 279.11.

Stoddard Solvent:  see PDF

Surface Impoundment:  Treatment, storage, or disposal of liquid hazardous wastes in ponds.

Surface Water:  All water naturally open to the atmosphere (rivers, lakes, reservoirs, ponds, streams, impoundments, seas, estuaries, etc.)

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  T   

Tetrachloroethylene (aka Perchloroethylene) :  see PDF

Toluene:  see PDF

Toxicity Waste:  see 40 CFR 261.24

Trichloroethane:  see PDF

Trichloroethylene:  see PDF

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  U   

Uniform Hazardous Waste Manifest:  A shipping document designed to track the movement of hazardous waste from its generator to its final resting place (cradle-to-grave).

Universal Waste:  A subset of hazardous wastes which are subject to reduced regulations if they are recycled. This includes: batteries, pesticides, lamps, and mercury-containing devices.

Up Gradient:  Opposite of the direction that groundwater flows; similar to “upstream” for surface water.

Used Oil:  Any oil that has been refined from crude oil, or any synthetic oil, which has been used and as a result of such use is contaminated by physical or chemical impurities.

Used Oil Aggregation Point:  Any site or facility that accepts, aggregates, and/or stores used oil collected only from other used oil generation sites owned or operated by the owner or operator of the aggregation point, from which used oil is transported to the aggregation point in shipments of no more that 55 gallons.

Used Oil Collection Center:  Any site or facility that accepts/aggregates and stores used oil collected only from household do-it-yourselfers.

Used Oil Generator:  Any business, by site, whose act or process produces used oil or whose act first causes used oil to become subject to regulation.

Used Oil Marketer:  Any person who directs a shipment of off-specification used oil from their facility to a used oil burner, or who first claims that the used oil that is to be burned for energy recovery meets the used oil fuel specifications in 40 CFR 279.11.

Used Oil Processor/Re-Refiner:  Any chemical or physical operation designed to produce: fuel oils, lubricants or other used oil derived products, from used oil.

Used Oil Transporter:  Persons who transport used oil, persons who collect used oil from more than one generator and transport the collected used oil, and owners and operators of used oil transfer facilities.

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  V   

Vadose Zone:  Also termed the unsaturated zone, is the portion of Earth between the land surface or zone of saturation. It extends from the top of the ground surface to the water table.

Volatiles:  Liquids which easily vaporize or evaporate at room temperature.

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  W   

  X   

Xylene:  see PDF

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  Y   

  Z