IADN— Integrated Atmospheric
IAP— Incentive Awards Program. Indoor
IAQ— Indoor Air Quality
IARC— International Agency for Research
IATDB— Interim Air Toxics Data Base
IBSIN— Innovations in Building Sustainable
IBT— Industrial Biotest Laboratory
IC— Internal Combustion
ICAIR— Interdisciplinary Planning and
ICAP— Inductively Coupled Argon Plasma
ICB— Information Collection Budget
ICBN— International Commission on the
Biological Effects of Noise
ICCP— International Climate Change Partnership
ICE— Industrial Combustion Emissions
Model. Internal Combustion Engine
ICP— Inductively Coupled Plasma
ICR— Information Collection Request
ICRE— Ignitability, Corrosivity, Reactivity,
ICRP— International Commission on Radiological
ICRU— International Commission of Radiological
Units and Measurements
ICS— Incident Command System. Institute
for Chemical Studies; Intermittent Control
Strategies.; Intermittent Control System
ICWM— Institute for Chemical Waste Management
IDLH— Immediately Dangerous to Life
IEB— International Environment Bureau
IEMP— Integrated Environmental Management
IES— Institute for Environmental Studies
IFB— Invitation for Bid
IFCAM— Industrial Fuel Choice Analysis
IFCS— International Forum on Chemical
IFIS— Industry File Information System
IFMS— Integrated Financial Management
IFPP— Industrial Fugitive Process Particulate
IGCC— Integrated Gasification Combined
IGCI— Industrial Gas Cleaning Institute
IIS— Inflationary Impact Statement
IINERT— In-Place Inactivation and Natural
IJC— International Joint Commission
(on Great Lakes)
IMM— Intersection Midblock Model
IMPACT— Integrated Model of Plumes and
Atmosphere in Complex Terrain
IMPROVE— Interagency Monitoring of Protected
INPUFF— Gaussian Puff Dispersion Model
IOB— Iron Ore Beneficiation
IOU— Input/Output Unit
IPCS— International Program on Chemical
IP— Inhalable Particles
IPM— Inhalable Particulate Matter. Integrated
IPP— Implementation Planning Program.
Integrated Plotting Package; Inter-media Priority
Pollutant (document); Independent Power Producer
IPCC— Intergovernmental Panel on Climate
IPM— Integrated Pest Management
IRG— Interagency Review Group
IRLG— Interagency Regulatory Liaison
Group (Composed of EPA, CPSC, FDA, and OSHA)
IRIS— Instructional Resources Information
System. Integrated Risk Information System
IRM— Intermediate Remedial Measures
IRMC— Inter-Regulatory Risk Management
IRP— Installation Restoration Program
IRPTC— International Register of Potentially
IRR— Institute of Resource Recovery
IRS— International Referral Systems
IS— Interim Status
ISAM— Indexed Sequential File Access
ISC— Industrial Source Complex
ISCL— Interim Status Compliance Letter
ISCLT— Industrial Source Complex Long
ISCST— Industrial Source Complex Short
ISD— Interim Status Document
ISE— Ion-specific electrode
ISMAP— Indirect Source Model for Air
ISO— International Organization for
ISPF— (IBM) Interactive System Productivity
ISS— Interim Status Standards
ITC—Innovative Technology Council
ITC— Interagency Testing Committee
ITRC— Interstate Technology Regulatory
ITRD— Innovative Treatment Remediation
IUP— Intended Use Plan
IUR— Inventory Update Rule
IWC— In-Stream Waste Concentration
IWS— Ionizing Wet Scrubber
Identification Code or EPA I.D.
Number— The unique code assigned to
each generator, transporter, and treatment,
storage, or disposal facility by regulating
agencies to facilitate identification and
tracking of chemicals or hazardous waste.
Ignitable— Capable of
burning or causing a fire.
IM240— A high-tech, transient
dynamometer automobile emissions test that
takes up to 240 seconds.
Imhoff Cone— A clear,
cone-shaped container used to measure the
volume of settleable solids in a specific
volume of water.
Immediately Dangerous to Life
and Health (IDLH)— The maximum level
to which a healthy individual can be exposed
to a chemical for 30 minutes and escape without
suffering irreversible health effects or impairing
symptoms. Used as a “level of concern.”
Imminent Hazard— One that
would likely result in unreasonable adverse
effects on humans or the environment or risk
unreasonable hazard to an endangered species
during the time required for a pesticide registration
Imminent Threat— A high
probability that exposure is occurring.
Immiscibility— The inability
of two or more substances or liquids to readily
dissolve into one another, such as soil and
water. Immiscibility The inability of two
or more substances or liquids to readily dissolve
into one another, such as soil and water.
Impermeable— Not easily
penetrated. The property of a material or
soil that does not allow, or allows only with
great difficulty, the movement or passage
Imports— Municipal solid
waste and recyclables that have been transported
to a state or locality for processing or final
disposition (but that did not originate in
that state or locality).
Impoundment— A body of
water or sludge confined by a dam, dike, floodgate,
or other barrier.
In Situ— In its original
place; unmoved unexcavated; remaining at the
site or in the subsurface.
In-Line Filtration— Pre-treattment
method in which chemicals are mixed by the
flowing water; commonly used in pressure filtration
installations. Eliminates need for flocculation
In-Situ Flushing— Introduction
of large volumes of water, at times supplemented
with cleaning compounds, into soil, waste,
or ground water to flush hazardous contaminants
from a site.
In-Situ Oxidation— Technology
that oxidizes contaminants dissolved in ground
water, converting them into insoluble compounds.
In-Situ Stripping— Treatment
system that removes or “strips”
volatile organic compounds from contaminated
ground or surface water by forcing an airstream
through the water and causing the compounds
Technology that treats contaminated soil in
place at extremely high temperatures, at or
more than 3000 degrees Fahrenheit.
In Vitro— Testing or
action outside an organism (e.g. inside a
test tube or culture dish.)
In Vivo— Testing or action
inside an organism.
Incident Command Post—
A facility located at a safe distance from
an emergency site, where the incident commander,
key staff, and technical representatives can
make decisions and deploy emergency manpower
Incident Command System (ICS)—
The organizational arrangement wherein one
person, normally the Fire Chief of the impacted
district, is in charge of an integrated, comprehensive
emergency response organization and the emergency
incident site, backed by an Emergency Operations
Center staff with resources, information,
Incineration— A treatment
technology involving destruction of waste
by controlled burning at high temperatures;
e.g., burning sludge to remove the water and
reduce the remaining residues to a safe, non-burnable
ash that can be disposed of safely on land,
in some waters, or in underground locations.
Incineration at Sea—
Disposal of waste by burning at sea on specially-designed
Incinerator— A furnace
for burning waste under controlled conditions.
Incompatible Waste— A
waste unsuitable for mixing with another waste
or material because it may react to form a
Indemnification— In the
pesticide program, legal requirement that
EPA pay certain end-users, dealers, and distributors
for the cost of stock on hand at the time
a pesticide registration is suspended.
Indicator— In biology,
any biological entity or processes, or community
whose characteristics show the presence of
specific environmental conditions. 2. In chemistry,
a substance that shows a visible change, usually
of color, at a desired point in a chemical
reaction. 3.A device that indicates the result
of a measurement; e.g. a pressure gauge or
a moveable scale.
Indirect Discharge— Introduction
of pollutants from a non-domestic source into
a publicly owned waste-treatment system. Indirect
dischargers can be commercial or industrial
facilities whose wastes enter local sewers.
Indirect Source— Any
facility or building, property, road or parking
area that attracts motor vehicle traffic and,
indirectly, causes pollution.
Indoor Air— The breathable
air inside a habitable structure or conveyance.
Indoor Air Pollution—
Chemical, physical, or biological contaminants
in indoor air.
Indoor Climate— Temperature,
humidity, lighting, air flow and noise levels
in a habitable structure or conveyance. Indoor
climate can affect indoor air pollution.
Industrial Pollution Prevention—
Combination of industrial source reduction
and toxic chemical use substitution.
Industrial Process Waste—
Residues produced during manufacturing operations.
Industrial Sludge— Semi-liquid
residue or slurry remaining from treatment
of industrial water and wastewater.
Industrial Source Reduction—
Practices that reduce the amount of any hazardous
substance, pollutant, or contaminant entering
any waste stream or otherwise released into
the environment. Also reduces the threat to
public health and the environment associated
with such releases. Term includes equipment
or technology modifications, substitution
of raw materials, and improvements in housekeeping,
maintenance, training or inventory control.
Industrial Waste— Unwanted
materials from an industrial operation; may
be liquid, sludge, solid, or hazardous waste.
Inert Ingredient— Pesticide
components such as solvents, carriers, dispersants,
and surfactants that are not active against
target pests. Not all inert ingredients are
Inertial Separator— A
device that uses centrifugal force to separate
Infectious Agent— Any
organism, such as a pathogenic virus, parasite,
or or bacterium, that is capable of invading
body tissues, multiplying, and causing disease.
Infectious Waste— Hazardous
waste capable of causing infections in humans,
including— contaminated animal waste;
human blood and blood products; isolation
waste, pathological waste; and discarded sharps
(needles, scalpels or broken medical instruments).
Infiltration— 1. The
penetration of water through the ground surface
into sub-surface soil or the penetration of
water from the soil into sewer or other pipes
through defective joints, connections, or
manhole walls. 2. The technique of applying
large volumes of waste water to land to penetrate
the surface and percolate through the underlying
A sub-surface groundwater collection system,
typically shallow in depth, constructed with
open-jointed or perforated pipes that discharge
collected water into a watertight chamber
from which the water is pumped to treatment
facilities and into the distribution system.
Usually located close to streams or ponds.
Infiltration Rate— The
quantity of water that can enter the soil
in a specified time interval.
Inflow— Entry of extraneous
rain water into a sewer system from sources
other than infiltration, such as basement
drains, manholes, storm drains, and street
Influent— Water, wastewater,
or other liquid flowing into a reservoir,
basin, or treatment plant.
Information Collection Request
(ICR)— A description of information
to be gathered in connection with rules, proposed
rules, surveys, and guidance documents that
contain information-gathering requirements.
The ICR describes what information is needed,
why it is needed, how it will be collected,
and how much collecting it will cost. The
ICR is submitted by the EPA to the Office
of Management and Budget (OMB) for approval.
Information File— In
the Superfund program, a file that contains
accurate, up-to-date documents on a Superfund
site. The file is usually located in a public
building (school, library, or city hall) convenient
for local residents.
All dust capable of entering the human respiratory
Initial Compliance Period (Water)—
The first full three-year compliance period
which begins at least 18 months after promulgation.
Injection Well— A well
into which fluids are injected for purposes
such as waste disposal, improving the recovery
of crude oil, or solution mining.
Injection Zone— A geological
formation receiving fluids through a well.
New or inventive methods to treat effectively
hazardous waste and reduce risks to human
health and the environment.
Innovative Treatment Technologies—
Technologies whose routine use is inhibited
by lack of data on performance and cost.
Inoculum— 1. Bacteria
or fungi injected into compost to start biological
action. 2. A medium containing organisms,
usually bacteria or a virus, that is introduced
into cultures or living organisms.
Chemical substances of mineral origin, not
of basically carbon structure.
Insecticide— A pesticide
compound specifically used to kill or prevent
the growth of insects.
Inspection and Maintenance
(I/M)— 1. Activities to ensure that
vehicles’ emission controls work properly.
2. Also applies to wastewater treatment plants
and other anti-pollution facilities and processes.
Waste generated at institutions such as schools,
libraries, hospitals, prisons, etc.
Instream Use— Water use
taking place within a stream channel; e.g.,
hydro-electric power generation, navigation,
water quality improvement, fish propagation,
Integrated Exposure Assessment—
Cumulative summation (over time) of the magnitude
of exposure to a toxic chemical in all media.
Integrated Pest Management
(IPM)— A mixture of chemical and other,
non-pesticide, methods to control pests.
Integrated Waste Management—
Using a variety of practices to handle municipal
solid waste; can include source reduction,
recycling, incineration, and landfilling.
Interceptor Sewers— Large
sewer lines that, in a combined system, control
the flow of sewage to the treatment plant.
In a storm, they allow some of the sewage
to flow directly into a receiving stream,
thus keeping it from overflowing onto the
streets. Also used in separate systems to
collect the flows from main and trunk sewers
and carry them to treatment points.
Interface— The common
boundary between two substances such as a
water and a solid, water and a gas, or two
liquids such as water and oil.
The strength of the film separating two immiscible
fluids (e.g. oil and water) measured in dynes
per, or millidynes per centimeter.
Interim (Permit) Status—
Period during which treatment, storage and
disposal facilities coming under RCRA in 1980
are temporarily permitted to operate while
awaiting a permanent permit. Permits issued
under these circumstances are usually called
“Part A” or “Part B”
Internal Dose— In exposure
assessment, the amount of a substance penetrating
the absorption barriers (e.g. skin, lung tissue,
gastrointestinal tract) of an organism through
either physical or biological processes.
Interstate Carrier Water Supply—
A source of water for drinking and sanitary
use on planes, buses, trains, and ships operating
in more than one state. These sources are
Interstate Commerce Clause—
A clause of the U.S. Constitution which reserves
to the federal government the right to regulate
the conduct of business across state lines.
Under this clause, for example, the U.S. Supreme
Court has ruled that states may not inequitably
restrict the disposal of out-of-state wastes
in their jurisdictions.
Interstate Waters— Waters
that flow across or form part of state or
international boundaries; e.g. the Great Lakes,
the Mississippi River, or coastal waters.
The continuous surveillance of the space between
the walls of an underground storage tank.
Intrastate Product— Pesticide
products once registered by states for sale
and use only in the state. All intrastate
products have been converted to full federal
registration or canceled.
Inventory (TSCA)— Inventory
of chemicals produced pursuant to Section
8 (b) of the Toxic Substances Control Act.
Inversion— A layer of
warm air that prevents the rise of cooling
air and traps pollutants beneath it; can cause
an air pollution episode.
Ion— An electrically
charged atom or group of atoms.
Ion Exchange Treatment—
A common water-softening method often found
on a large scale at water purification plants
that remove some organics and radium by adding
calcium oxide or calcium hydroxide to increase
the pH to a level where the metals will precipitate
Ionization Chamber— A
device that measures the intensity of ionizing
Ionizing Radiation— Radiation
that can strip electrons from atoms; e.g.
alpha, beta, and gamma radiation.
IRIS— EPA’s Integrated
Risk Information System, an electronic data
base containing the Agency’s latest
descriptive and quantitative regulatory information
on chemical constituents.
Irradiated Food— Food
subject to brief radioactivity, usually gamma
rays, to kill insects, bacteria, and mold,
and to permit storage without refrigeration.
to radiation of wavelengths shorter than those
of visible light (gamma, x-ray, or ultra-
violet), for medical purposes, to sterilize
milk or other foodstuffs, or to induce polymerization
of monomers or vulcanization of rubber.
Effect characterized by the inability of the
body to partially or fully repair injury caused
by a toxic agent.
water or wastewater to land areas to supply
the water and nutrient needs of plants.
The amount of water stored in the crop root
zone compared to the amount of irrigation
Irrigation Return Flow—
Surface and subsurface water which leaves
the field following application of irrigation
Irritant— A substance
that can cause irritation of the skin, eyes,
or respiratory system. Effects may be acute
from a single high level exposure, or chronic
from repeated low-level exposures to such
compounds as chlorine, nitrogen dioxide, and
than one sample point exhibiting the same
Isopleth— The line or
area represented by an isoconcentration.
Isotope— A variation
of an element that has the same atomic number
of protons but a different weight because
of the number of neutrons. Various isotopes
of the same element may have different radioactive
behaviors, some are highly unstable.
Isotropy— The condition
in which the hydraulic or other properties
of an aquifer are the same in all directions.