DeKalb CERP Appendices

Appendix A — Glossary

The following list of terms and abbreviations includes many of those that appear in technical documents on chemical safety and emergency management, as well as those used on this website. It is not intended to be a complete list of such terms. Nevertheless, if you find some term that is not listed here, but which you feel needs definition or a brief explanation, feel free to contact the LEPC. Our e–mail address is on the top of our home web page.

Most of the links from within the glossary entries are cross–references to other entries in the glossary. This avoids multiple definitions of terms, and reduces the size of the glossary. If you need to see what a linked word in the definition means, just follow the link, then go back in your browser. When a link is to another website (outside the LEPC's), it is followed by a external link symbol.

The head entries in the glossary are in alphabetical order. The following index will take you to the entries that start with the indicated letter. Either mouse click on the letter, or type "Alt-X Enter", where "X" is the index letter, typed while holding the Alt key down, and "Enter" is the keyboard Enter key. The latter option will work from anywhere on this page.


Abatement: Partial or complete reduction of a polutant.
Absorption: Generally, incorporation of a gas or liquid into a solid by capillary action, osmosis or the like. For a person or an animal, absorption is the process of a gaseous or liquid substance getting into the body through the eyes, skin, stomach, intestines, or lungs. Compare to adsorption.
Acclimatization: Physiological and behavioral adjustments of an organism to changes in its environment.
ACCP: Access Control Coordination Point. The location to which agency representatives are directed so that they can pass through the security perimeter at an incident.
ACGIH: American Conference of Governmental Industrial Hygienists . Organization that develops and publishes BEI ^® and TLV^® values. Despite the name, their members may include "anyone engaged in the occupational hygiene, environmental health, occupational health, or safety professions even if their primary employment is not with a government agency".
Acrid: An irritating, bitter odor.
Action level: The exposure level, as a concentration in air at which OSHA regulations take effect to protect employees. Exposure at or above this level is termed "occupational exposure." It is generally set at one half the PEL concentration.
Active ingredient: A component of a product that directly contributes to the product's function, as opposed to an inert ingredient.
Acute: Of an illness, occurring quickly and for a short time, as opposed to chronic. Acute exposure to a substance is contact with the substance that occurs once or for only a short time (up to 14 days), as opposed to chronic exposure.
Additive: A biologic response to exposure to multiple substances that equals the sum of responses of all the individual substances added together [compare with antagonistic effect and synergistic effect].
ADI: Acceptable Daily Intake. This is the dose of a substance which can be consumed every day for a lifetime in the practical certainty, on the basis of all known facts, that no harm will result. It is typically measured in mg/kg units. See also RfD, and ARfD.
Adsorption: Retention of gas or liquid molecules on the surface of a solid. "Activated charcoal/carbon," which is finely granulated to give it a large surface area, is commonly used to adsorb gases. Compare to absorption.
Aerosol: A suspension of fine solid particles (dust, smoke) or liquid drops (mist, fog) of a substance in air, small enough to remain suspended for an extended period of time.
ALA: Short for δ-aminolevulinic acid, an organic chemical compound whose structure is shown on the right. When detected, it is an indicator of lead exposure.
ALARA: As Low As Reasonably Achievable
Allergy: A condition in which initially symptomless exposure to a substance (called an "allergen") results in later sensitivity to the substance.
ALOHA: Aerial Location of Hazardous Atmospheres. Part of the CAMEO suite of programs that indicates how chemicals spread through the air depending on weather conditions. Developed jointly by the EPA and NOAA.
Ambient: Refers to existing or normal conditions of temperature, humidity, and the like.
Amino acid: An organic chemical compound that has both at least one carboxylic or acid group (COOH) and at least one amine group (usually NH₂) group. They are the basic components of proteins, and otherwise occur naturally (see example ALA) and as artificially manufactured (see example EDTA).
Anemia: A condition in which the blood is deficient in red blood cells, hemoglobin or volume.
Anoxia: A condition in which there is relative lack of oxygen in the blood or tissues.
Antagonistic: A biologic response to exposure to multiple substances that is less than would be expected if the known effects of the individual substances were added together [compare with additive effect and synergistic effect].
Antidote: A remedy used to counteract a poison's toxic effects, by eliminating, absorbing, chelating, or neutralizing the poison.
AOR: Area[s] Of Responsibility.
Apnea: Temporary stoppage of breathing. See also dyspnea.
Aqueous: Having to do with water. An aqueous solution of a substance is one with water as the solvent.
ARES: Amateur Radio Emergency Service. Volunteer organization of amateur radio operators who are trained and equipped to assist with communications in an emergency, as well as for non-emergency public service events. See also RACES.
ARfD: Acute Reference Dose. This is the dose of a substance that can be consumed over a short period of time (usually during one meal or in one day), without an appreciable health risk to the consumer, based on all known facts at the time. See also RfD, and ADI.
Asphyxiant: A gas or vapor that can cause unconsciouness or death by suffocation (anoxia). Simple asphyxiants displace oxygen; chemical asphxiants interfere with the body's ability to intake or use oxygen.
Asthenia: Loss of strength or energy.
ASTM: The American Society for Testing Materials, an organization that develops widely used industry standards.
ATSDR: (HHS) Agency for Toxic Substances and Disease Registry , created by CERCLA. Mission is to serve the public by using the best science, taking responsive public health actions, and providing trusted health information to prevent harmful exposures and disease related to toxic substances. Specific agency functions include public health assessments of waste sites, health consultations concerning specific hazardous substances, health surveillance and registries, and response to emergency releases of hazardous substances.


BEI^®: Biological Exposure Index. Guidance values developed by the ACGIH for assessing biological monitoring results. BEIs^® represent the levels of determinants that are most likely to be observed in specimens collected from healthy workers who have been exposed to chemicals to the same extent as workers with exposure at the Threshold Limit Value (TLV^®). There are currently more than 50 of these. For more details on how this works, see the ACGIH's Introduction to BEI^®.
BLEVE: Boiling Liquid Evaporating Vapor Explosion [pronounced "blevy"]. The explosive release of expanding vapor and boiling liquid following the catastrophic failure of a pressure vessel holding a pressurized liquefied gas such as propane or LPG, especially when exposed to fire. Transportation BLEVE incidents involving hazardous substances may pose significant threats from explosions as well as contamination. A BLEVE does not require a flammable substance to occur, but in the case of flammable vapors, a fireball or fuel-air explosion is likely.
Body burden: The total amount of a substance in the body. Some substances build up in the body because they are stored in fat or bone or because they leave the body very slowly.
Bradycardia: Slowed heart beat, generally meaning less than 60 pulses per minute. Compare to tachycardia.
Buffer: A substance that reduces the change in pH that might otherwise occur when there is an addition of an acid or alkali.
[n–]Butyl acetate: The organic chemical compound, whose molecular structure is shown at the right, and whose name is commonly abbreviated "BuAc". BuAc is used as the standard reference material for determining relative evaporation rate, using the ASTM Standard Test Method D3539–87 (2004).


CAA: The Clean Air Act of 1970, as amended. 40 CFR 50–80. The EPA has enforcement authority.
CAMEO: Computer–Aided Management of Emergency Operations. A suite of programs that assist planners for and responders to chemical release emergencies. Also refers to the database of over 6000 hazardous chemicals that comes with the programs. Other CAMEO components are ALOHA and MARPLOT. See also the CAMEO information on the EPA website. The program is compatible with LandView.
carbon dioxide: See CO₂ .
carbon monoxide: See CO.
Carcinogen: A substance that tends to cause cancers. Carcinogenicity is the degree to which the substance is capable of causing cancers.
CAS: Chemical Abstracts Service, a function of Chemical Abstracts, a scientific journal published by the American Chemical Society (ACS). They index papers published in the journal by the chemicals referenced in them, using a numeric coding system, called "Registry Numbers" (RN). RNs are commonly used to refer briefly and unambiguously to hazardous materials.
Catalyst: A chemical substance that facilitates or increases the rate of a chemical reaction without itself being consumed in the reaction.
CDRG: Catastrophic Disaster Response Group.
CEC: Community Emergency Coordinator. The individual or agency appointed by the LEPC who receives emergency notification of hazardous materials incidents under the provisions of EPCRA.
Ceiling value: The concentration of a substance that must never be exceeded at any time in the workplace, under OSHA regulations.
CEOC: County Emergency Operations Center. See also EOC.
CEPPO: (EPA) Chemical Emergency Preparedness & Prevention Office . Former name of the agency now known as OEPPR.
CERCLA: Comprehensive Environmental Response, Compensation, and Liability Act, 40 CFR 300. Also known as the "Superfund" Act, it provides funds to clean up hazardous materials releases into the environment The EPA has jurisdiction over its provisions.
CERP: Comprehensive Emergency Response Plan. Developed by the LEPC to provide detailed information that would be needed in a chemical release incident. A requirement of EPCRA.
CERT: Community Emergency Response Team. A group of private citizens who have trained and equipped themselves so as to be prepared to help themselves, their families, their neighbors and their communities in case of local emergencies and disasters.
CFR: Code of Federal Regulations. The set of 50 (as of 2005), typically multi–volume, documents that contain the text of all current US government regulations. Available from the National Archives and Records Administration.
Chelating agent: A chemical, such as EDTA or DMSA, that can form a chemical complex with a metal atom or ion, especially one that is toxic, and that is generally hydrophilic. Since the complex is also water soluble, it thus can be more easily eliminated from the body.
CHEMTREC: CHEMical TRansportation Emergency Center . Established by the Chemical Manufacturers Association (CMA) to provide information on materials involved in transportation accidents.
Chronic: Of an illness caused by a hazardous substance: occurs after an extended period of exposure to the substance, and/or continues for an extended time period, as opposed to acute. Of exposure to a substance, occurring over an extended period (typically more than a year).
CO (carbon monoxide): A colorless, odorless, flammable gas resulting from incomplete burning of carbon compounds. A chemical asphyxiant, it severely reduces the blood's ability to carry oxygen by binding strongly to hemoglobin.
CO₂ (carbon dioxide): A dense colorless gas. Though relatively non-toxic and unreactive, it can displace oxygen and thus become a simple asphyxiant or a fire-extinguishing agent.
Concentration: The amount (mass or volume) of a substance in relation to the mass of, or in a specified volume of, the containing substance. For hazardous materials in the air, concentration is typically measured either in micrograms per cubic meter (µg/m³) or in parts per million (ppm) by mass (w/w).
Confined space: Spaces hazardous to an occupant due to limited means of escape combined with other possible hazards, including exposure to air contaminants or asphyxiants.
Corrosive: Causing visible destruction of or irreversible alterations to living tissue by chemical action at the site of contact.
CV: Comparison value. Calculated concentration of a substance in air, water, food, or soil that is unlikely to cause harmful (adverse) health effects in exposed people. The CV is used as a screening level during the public health assessment process. Substances found in concentrations greater than their CVs might be selected for further evaluation in the public health assessment process.
CP: Command Post. See also ICP.
CWA: Clean Water Act of 1972 and as later amended, 40 CFR 100–140, 400–470. Regulates discharge of polutants into surface waters. The EPA and Army Corps of Engineers have jurisdiction.


DC: DeKalb County.
Decon: Decontamination.
Demulcent: A material used to soothe or protect inflamed, irritated mucous membranes.
Denature: With respect to an organic chemical compound, such as a protein, means to change its properties so as to reduce or eliminate its biological function. This can be done by heating, or by treatment with various chemicals. Also used to mean adding a substance to an otherwise edible or drinkable material (particularly alcohol) to make it poisonous or unpalatable.
Dermal: Referring to the skin. For example, dermal absorption means passing through the skin.
Dermatitis: Skin rash; inflammation of the skin.
Detection limit: The lowest concentration of a substance that can reliably be distinguished from a zero concentration.
DFO: (FEMA) Disaster Field Office.
DHS: (US Federal) Department of Homeland Security .
Diaphoresis: Perspiration, especially when profuse.
DMSA: meso-2,3-dimercaptosuccinic acid. An organic chemical compound whose structure is shown at the right. Acts as a chelating agent for most heavy metals, and is thus used as an antidote for poisoning by lead and mercury, among others. See also EDTA.
Dose: The mean mass of a substance incorporated into a living being as a ratio to its body mass. Usually measured in milligrams of substance per kilogram of body mass [mg/kg or parts per million (ppm)] or in micrograms of substance per kilogram of body mass [µg/kg or parts per billion (ppb)]. The concentration of the substance in specific body tissues may vary widely. An "exposure dose" is how much of a substance is encountered in the environment. An "absorbed dose" is the mass of a substance that was actually absorbed into the body.
Dose-response relationship: A mathematical model of the changes in body function or health (response) to the amount of exposure [dose] of a substance.
DOT: (US Federal) Department of Transportation . See some DOT functions relevant to materials safety under the headings PHMSA, the OET and RITA. They provide four-digit numbers used to identify materials for regulation or transportation, under 49 CFR 172.101, which numbers can be seen on diamond-shaped placards attached to vehicles that are transporting these materials.
DRO: (Red Cross) Disaster Relief Operation. An organized activity of the Red Cross, usually conducted in cooperation with other relief agencies, that provides essentials (such as shelter, food, medicines) to victims of a disaster, as well as performing other relief–related functions.
Dyspnea: Difficulty in breathing; shortness of breath. See also apnea.


EAS: The Emergency Alert System. Radio and TV broadcasters and cable TV stations are required by the FCC to have the means to alert their audience when an emergency situation occurs in their area. Usually announced by a loud beep. Tests of the EAS end with the familiar message "If this had been an actual emergency ...."
EC₅₀: Median Effective Concentration. The concentration of a substance in the environment expected to cause a specified biological effect on 50% of exposed animals.
ED₅₀: Median Effective Dose. The dose of a substance expected to cause a specified biological effect on 50% of animals.
Edema: Accumulation of fluid in tissues, leading to swelling or obstruction. Pulmonary edema is associated with pneumonia.
EDTA: Ethylenediaminetetraacetic acid (or ethylenediaminetetraacetate). A synthetic amino acid (or acid salt) that acts as a chelating agent for many divalent metal ions, particularly lead (Pb⁺²). A diagram of the acid's molecular structure is shown to the right. EDTA is used medically as an antidote for lead or other heavy metal poisoning in the form of the di-sodium salt, chelated with calcium: Na₂Ca–EDTA; as a food preservative; and as an anticoagulant for stored blood (chelating Ca⁺²). See also DMSA.
EEGL: Emergency Exposure Guidance Level. An acceptable concentration of a substance for unpredicted, single, short–term exposure of a defined occupational group (such as military personnel) to that substance. Developed by the National Academy of Sciences, NRC.
EFATG: Emergency First Aid Treatment Guide. See Appendix B.
EHS: Extremely Hazardous Substance(s). A term for substances that must be reported if stored in sufficient quantity to be a potential threat. See Appendix B.
Electrolyte: A substance that in aqueous solution conducts electricity. In an animal, these are usually dissolved salts containing sodium or potassium ions. Electrolytes are also called ionic solutes. The concentration of electrolytes in blood affects bodily functions. For example, sodium and potassium ions are vital to the function of nerves, but too much of either is dangerous.
EMA: Emergency Management Agency. A generic term, often used for a local governmental agency responsible for dealing with emergencies of all kinds. Similar in meaning to ESDA.
Emesis / emetic: An emetic is a substance that can cause or induce vomiting (emesis).
EMI: Emergency Management Institute. A training arm of FEMA.
EMS: Emergency Medical Services.
EMT: Emergency Medical Technician.
EOC/EOF: Emergency Operations Center/Facility. In an emergency, agencies responsible for dealing with the situation meet in this area of an ESDA or EMA office to share information and coordinate their activities. See also CEOC and SEOC.
EPA: (US Federal) Environmental Protection Agency . Administers among others, the CAA, CWA, CERCLA, RCRA and TSCA.
EPCRA: US Emergency Planning & Community Right–to–know Act. This is Title III of SARA, under the provisions of which all LEPCs are organized.
Epidemiology: The study of the distribution and determinants of disease or health status in a population; the study of the occurrence and causes of health effects in humans.
ERG2004: Emergency Response Guidebook, 2004 edition. Latest issue of the book issued by DOT, which contains descriptions of the hazardous materials that may be tranported on North American roads, and of the placards that identify the materials.
ESDA: Emergency Services & Disaster Agency. A generic term, often used for a local governmental agency responsible for dealing with emergencies of all kinds. Similar in meaning to EMA. DeKalb County has an ESDA.
Etiologic agent: A material that can cause illness.
Evaporation Rate: In the terms used for MSDS, it is the ratio of the rate at which the substance described in the MSDS evaporates (changes state from a liquid to a gas) to the rate of evaporation of a standard chemical: n-butyl acetate, under standard conditions, as specified by the ASTM as Standard Test Method D3539–87 (2004). Evaporation rate information can be useful in evaluating the health and fire hazards of a material. For example, a substance with a high evaporation rate will readily form a vapor that can be inhaled or that can explode. Since evaporation rate is a ratio of like terms, it has no units. Substances with an evaporation rate greater than 3 are considered "fast" evaporators; those with a rate less than 0.8 are considered "slow". N-butyl acetate itself, whose evaporation rate is by definition 1, is considered "medium".
EVC: Equilibrium Vapor Concentration. The limiting atmospheric concentration of the vapor phase of a substance in contact with the liquid (or solid) phase of the same substance, at a specified temperature (typically "room temperature" — 25 °C).


FAA: US Federal Aviation Authority. Among other things, regulates and controls quantity and packaging of substances sent by air.
FCC: US Federal Communications Commision. The government agency responsible for regulating the broadcast, cable, phone, and other communications media within the US and its possessions.
FEMA: US Federal Emergency Management Agency . FEMA is part of the Department of Homeland Security's Emergency Preparedness and Response Directorate. FEMA works in partnership with other organizations that are part of the nation's emergency management system including state and local emergency management agencies, 27 federal agencies and the American Red Cross. FEMA's mission is to lead the effort to prepare the nation for all hazards and effectively manage federal response and recovery efforts following any national incident. FEMA also initiates proactive mitigation activities, trains first responders, and manages the National Flood Insurance Program and the U.S. Fire Administration.
Fibrosis: Scarring. Pulmonary fibrosis can produce anoxia.
FOIA: Freedom Of Information Act — 5 U.S.C. §552, under which citizens can request certain kinds of information from public agencies. For security reasons, information on Tier II sites in DeKalb County must be requested under FOIA.
FPD: Fire Protection District.
FRP: Federal Response Plan.


GIS: Geographic Information System. A computerized mapping system that divides geographic and statistical data into viewable layers that can be removed or included depending on the user's needs.


Half–life: The period of time required to reduce the concentration of a substance by one half. In the environment, the half–life is the time it takes for half the original amount of a substance to disappear when it is changed to another chemical by bacteria, fungi, sunlight, or other chemical or physical processes. In the human body, the half–life is the time it takes for half the original amount of the substance to disappear, either by being changed to another substance or by leaving the body.
HazCom: Hazard Communication. Required by the OSH Act.
HazMat: Short form for "Hazardous Materials". See details under the heading HM.
HAZWOPER: HAZardous Waste OPerations and Emergency Response. OSHA standard 29CFR1910.120 regulates safety and health of people involved in the clean-up and decontamination response to hazardous materials releases.
HHS: (US Federal) Department of Health and Human Services .
HM: Hazardous Materials. See also "HazMat". A hazardous material includes any substance that is a health or physical hazard as defined by OSHA. OSHA Regulations require that an MSDS be kept on hand for all hazardous materials. Such a substance may harm or injure humans, animals, agriculture, structures, waterways, highways, the environment, or other public or private property.
HMEP: Hazardous Materials Emergency Preparedness.
Homogeneous: Uniform in composition throughout a mass of material, at all relevant measurement scales. Not "lumpy".
Hydrophilic: Generally, "compatible with water." Can mean that a substance easily absorbs, is wetted by, or dissolves in water. As opposed to "hydrophobic".


ICP: Incident Command Post. Location from which an Incident Commander operates under the ICS.
ICS: Incident Command System. The mechanism used to coordinate the activities of multiple agencies responding to a disaster, led by an Incident Commander (IC). For more details on ICS, see this web site: What is the ICS? ICS is widely used today on a local level, but is supplemented by the UCS, and is being replaced on a national level by NIMS.
IDLH: Designates the concentration of a hazardous material that is Immediately Dangerous to Life or Health. Values were determined by NIOSH.
IDNS: Illinois Department of Nuclear Safety.
IEMA: Illinois Emergency Management Agency. IEMA is the SERC for Illinois.
Incidence: The number of new cases of disease in a defined population over a specific time period [contrast with prevalence].
Incompatible: A combination of two or more chemicals that gives an undesired reaction when mixed. This usually refers to a mixture that will react to cause an imminent threat to health and safety through an explosion, fire, and/or formation of toxic materials. The MSDS for a substance is supposed to list its incompatibilities. Be aware that even ordinary household chemicals — notably bleach and ammonia — can be incompatible.
IOMA: Illinois Open Meetings Act . All DeKalb County LEPC meetings are conducted in accordance with this law.
IPC: The Illinois Poison Center. Serves all of Illinois 24 hours a day, 365 days a year. Staffed by nurses, physicians, pharmacists and other poison specialists, the IPC offers free, confidential poison prevention advice and treatment recommendations via a toll–free hot line, 1–800–222–1222. The IPC also has informative and preventative information at their website .
ISFI: Illinois State Fire Institute. Provides training for fire fighters.


JCAHO: Joint Commission on Accreditation of Health–care Organizations . Evaluates and accredits nearly 17 000 health–care organizations and programs in the United States. Focused on improving the quality and safety of care.
JIC: Joint Information Center. Common source for several organizations and agencies to provide coordinated and verified information to the public in the case of an emergency.


Kinetic rate coefficient: A number that describes the rate at which, for example, an air pollutant reacts.
KSA: Knowledge, Skills, and Abilities.


LandView: A GIS from the US Census Bureau that can be used with MARPLOT to estimate the number of people affected by a hazardous materials release. See also CAMEO.
Latency period: The time interval between exposure to a toxic substance and the first manifestation of illness caused by that substance. May range from a few seconds to decades.
LC₅₀: Median Lethal Concentration. The concentration value of a hazardous material at which 50% of animals would be expected to die from its effects; a calculated value.
LCLO: Lethal Concentration LOw. The lowest concentration of a hazardous material at which death occurred.
LD₅₀: Median Lethal Dose. The dose of a hazardous material at which 50% of animals would be expected to die from its effects; a calculated value.
LDLO: Lethal Dose LOw. The lowest dose of a hazardous material at which death occurred.
LEL: Lower Explosive Limit. The atmospheric concentration of a flammable hazardous material below which it lacks sufficient fuel to be subject to explosion. Also known as the Lower Flammable Limit (LFL). See also UEL.
LEPC: Local Emergency Planning Committee. A group responsible for developing plans to deal with release of hazardous materials. In Illinois, there is an LEPC in every county, established by IEMA, the SERC for Illinois. The legal provisions for LEPC organization are part of EPCRA.
Lesion: An abnormal change, injury or damage to a tissue.
LOAFL: Lowest Observed Adverse Effect Level. The lowest tested dose of a substance that has been reported to cause harmful (adverse) health effects in people or animals.
LOC [plume]: Level Of Concern. In the context of hazardous materials releases, the maximum TWA atmospheric concentration of a substance to which members of the general public can be exposed, for a specified period of time (typically 15 minutes). For smoke, for example, the LOC concentration is 150 µg/m³ for up to 1 hour. For hazardous materials, the LOC is usually set at 0.1 times the IDLH value.

An "LOC plume" is the volume of dispersed substance in the air that exceeds the LOC concentration.


MAA: Mutual Aid Agreement.
MABAS: Mutual Aid Box Alarm System . An organization of more than 550 fire-fighting departments in Illinois and southern Wisconsin. Provides a mechanism for fire fighters to get assistance from other FPDs as required. Includes the Cortland, DeKalb City, Genoa-Kingston, Hinckley, Kirkland, Maple Park, Sandwich, Shabbona, Somonauk, Sycamore, and Waterman FPDs, among others.
MARPLOT: Part of CAMEO, jointly developed by the EPA (OEPPR), NOAA, and the US Census Bureau. A GIS that shows areas affected by a HazMat incident on street–level maps. See also LandView.
MERS: Mobile Emergency Response System.
MHI: Material Hazard Index. A number used to rank chemical materials to determine the level of controls necessary for regulation. MHI is determined by dividing the EVC of a material at 25 °C by the LOC value for that material in the same units.
MSDS: Material Safety Data Sheet. One of around 500,000 documents that details the characteristics of a substance sold or used in the US. Both the OSHA Hazard Communication (HazCom) Standard and EPRCA §311 require employers to have an MSDS for each hazardous chemical in their facility. Many of the MSDS can be looked up at this web site: Cornell University MSDS .


Narcosis: A state of drowsiness, stupor, or greatly reduced activity. Often associated with drugs, it can be caused by a number of substances.
NECC: National Emergency Coordination Center of FEMA.
Neurotoxin: A substance whose primary toxic effect is on the central nervous system (CNS).
Neutralize: To make a substance less chemically reactive, or to change the ambient pH to approximately 7.
NFA: National Fire Academy. Run by FEMA's US Fire Administration in Emmitsburg MD.
NFPA: National Fire Protection Association . An international voluntary organization formed to promote and improve fire protection and prevention. Publishes the National Fire Codes, a multi-volume set of standards, recommended practices and manuals.
NIMS: National Incident Management System. Developed and managed by DHS, this is a version of ICS and UCS for use at a national level. As a central part of the NRP, NIMS provides a consistent nationwide template to enable all government, private–sector, and nongovernmental organizations to work together during domestic incidents. This system is expected to be in place by the end of 2006. For further information, see the NIMS website from FEMA, and the on–line course on NIMS offered by the EMI.
NIOSH: National Institute for Occupational Safety and Health . An organization under the US Department of Health and Human Services' Centers for Disease Control & Prevention (CDC). Publishes the RTECS.
NOAA: US National Oceanic & Atmospheric Administration. Runs the National Weather Service (NWS), which provides weather forecasts nationwide, especially through its network of NOAA Weather Radio stations. Co–developer of ALOHA, since weather conditions strongly affect the distribution of hazardous materials in the air.
NOAEL: No Observed Adverse Effect Level.
Noxious: Capable of causing injury, or harmful effects on health. See also "toxic".
NRC: National Research Council of the National Academy of Sciences.
NRC: National Response Center of the EPA. Receives reports of hazardous materials releases.
NRP: National Response Plan. Establishes a comprehensive all-hazards approach to enhance the ability of the United States to manage domestic incidents. The plan incorporates best practices and procedures from incident management disciplines — homeland security, emergency management, law enforcement, firefighting, public works, public health, responder and recovery worker health and safety, emergency medical services, and the private sector — and integrates them into a unified structure. The NRP is predicated on NIMS. Together the NRP and the NIMS provide a nationwide template for working together to prevent or respond to threats and incidents regardless of cause, size, or complexity.
NVOAD: National Voluntary Organizations Active in Disaster. Organization of American national disaster relief agencies with the goal of fostering more effective service to people affected by disaster. The key NVOAD principles are cooperation, coordination, communication, education, mitigation, convening mechanisms, and outreach. There are national members, and also state VOADs.
NWS: National Weather Service. See NOAA.


OEM: Office of Emergency Management.
OEPPR: (EPA) Office of Emergency Prevention, Preparedness & Response . Formerly known as CEPPO (their web site still reflects the older name). Coordinates the EPA's activities in determining how to maintain the quality of life and still manage chemicals safely, and in building programs to respond to and prevent chemical accidents.
OET: The Office of Emergency Transportation of DOT performs coordinated crisis management functions for multimodal transportation emergencies, including natural disasters and technological incidents or accidents.
Organic chemicals/compounds: Naturally occuring (animal– or plant–produced) or synthetic substances containing carbon, plus some combination of hydrogen, oxygen, and nitrogen. Phosphorus and sulfur are also often part of an organic compound. More than 10 million have been identified. The opposite is "inorganic". For examples, see the entries for ALA, n–butyl acetate, DMSA and EDTA.
ORM: Other Regulated Material. A DOT classification of some hazardous materials for labeling during transportation.
OSH Act: US Occupational Safety and Health Act of 1970, 29 CFR 1910 et seq. Administered by OSHA for firms with ten or more employees. The act established the Hazard Communication (HazCom) Rule.
OSHA: US Occupational Safety and Health Administration . Federal agency, part of the Department of Labor, responsible for worker safety and health.
Osmosis: Passage of a fluid through a membrane to equalize a concentration on both sides.
OSWER: Office of Solid Waste & Emergency Response. Part of EPA.
Oxidizer: Abbreviated "OX". The DOT narrowly defines an oxidizer or oxidizing material as a substance that readily yields oxygen to cause or enhance the combustion [burning] of other materials. Some oxidizers, such as chlorine, act only when exposed to other substances. The definition of oxidizer in chemistry is broader.


PDF: Portable Document Format. Developed by Adobe^® Systems, Incorporated, it is a widely used and supported form for distributing documents electronically. Some of the information available from this website is in PDF files. For more information, see the Adobe PDF webpage.
PEL: Permissible Exposure Limit. The maximum or TWA amount or concentration of a substance to which a worker may be exposed, under OSHA regulations. About 470 substances have OSHA PEL's. Exposure can be by inhalation, or by absorbtion through the skin or eyes.
Percutaneous: Through the skin, refering to the absorption of a chemical.
pH: Roughly, a measure of the acidity or alkalinity of a substance. Substances with pH much below 7 are acid; the lower the value, the more acid. Those much above 7 are alkaline; the higher the value, the more alkaline. Those with pH values around 7 are neutral. The chemical definition precisely defines how this number is determined.
PHC: Principal Hazardous Constituent.
PHMSA: The Pipeline and Hazardous Materials Safety Administration of DOT has public responsibilities for safe and secure movement of hazardous materials to industry and consumers by all transportation modes, including the nation's pipelines.
Photophobia: Intolerance to light.
Plume: A volume of a substance that moves from its source to places farther away from the source. Plumes can be described by the volume of air or water they occupy and the direction they move. For example, a plume can be a column of smoke from a chimney or a substance moving with groundwater.
Pneumonia: A disease characterized by inflammation of and accumulation of fluids in the lungs. Although usually thought of as an infectious disease, pneumonia can also be caused by physical and chemical irritants, or inhaled fluids.
POHC: Principal Organic Hazardous Constituent.
PPE: Personal Protective Equipment. Devices or clothing used to help isolate a person from direct exposure to hazardous materials.
ppm / ppb: Designates a concentration expressed in Parts Per Million or in Parts Per Billion (thousand million). Usually this is the ratio by mass ("weight"), often designated by the suffix "w/w", but it is occasionally by volume, designated "v/v".
Prevalence: The number of existing disease cases in a defined population during a specific time period [contrast with incidence].
PRP: Potentially Responsible Party. A company, government, or person legally responsible for cleaning up the pollution at a hazardous waste site under Superfund. There may be more than one PRP for a particular site.
Public health advisory: A statement made by ATSDR to EPA or a state regulatory agency that a release of hazardous substances poses an immediate threat to human health. The advisory includes recommended measures to reduce exposure and reduce the threat to human health.
Pulmonary: Pertaining to the lungs, as in pulmonary fibrosis or pulmonary edema.
Pyrolysis: Chemical decomposition produced by heating, as in a fire.
Pyrophoric: A susbtance that can spontaneously burn when exposed to air. It is not only atmospheric oxygen that ignites them: they may also burn more intensely if a CO₂ fire extinguisher is used on them, or if they are exposed to water (liquid or vapor). Not a household item, but this type of material is often used in chemical manufacturing.


RACES: Radio Amateur Civil Emergency Service. Volunteer organization of amateur radio operators organized under a sponsoring government agency, typically an ESDA or EMA. RACES members are prepared to assist with communications in an emergency, when activated by the sponsoring agency. See also ARES.
RCRA: The Resource Conservation and Recovery Act of 1976. Authorized the EPA to control hazardous waste from "cradle to grave", including its generation, transportation, treatment, storage, and disposal. The corresponding EPA regulations are in 40 CFR 240–299. RCRA also created a framework for management of non–hazardous wastes. In 1984, the Hazardous and Solid Waste Amendments (HSWA) were added to RCRA. This requires phasing out of landfill disposal of hazardous waste.
RfD: Reference Dose. An EPA estimate, with uncertainty or safety factors built in, of the daily lifetime dose of a substance that is unlikely to cause harm in humans. See also ARfD, and ADI.
RITA: The Research and Innovative Technology Administration of DOT was created in 2005 to coordinate and manage the department's research, and to expedite implementation of new technology.
RN: The Registry Number used by CAS to identify chemicals.
RQ: Reportable Quantity. Any release of one or more of the roughly 800 CERCLA or 360 EPCRA hazardous substances that equals or exceeds this quantity (RQ) in any 24–hour period must be reported to the NRC at the EPA. The RQs are adjusted to one of five levels: 1, 10, 100, 1000, or 5000 pounds. EPA bases adjustments to the RQs on the intrinsic characteristics of each hazardous substance, such as the aquatic toxicity, acute and chronic toxicity, ignitability, reactivity, and potential carcinogenicity. An RQ value is established for each of these characteristics of a hazardous substance, with the most stringent RQ value (i.e., the lowest quantity) becoming the final RQ or reporting trigger for that hazardous substance.
RSPA: The research functions of the Research and Special Programs Administration of DOT were replaced in 2005 by RITA. The pipeline safety function was moved to PHMSA. The OET became part of the office of the Secretary.
RTECS: Registry of Toxic Effects of Chemical Substances, published by NIOSH. Has toxicity data on numerous materials, with references to the studies that generated the data.


SARA: Superfund Amendments & Reauthorization Act of 1986. Title III of SARA is EPCRA, under the provisions of which the LEPC was organized.
SEOC: State Emergency Operations Center. See also EOC.
SERC: State Emergency Response Commission. A general term used to designate the state agency responsible under EPCRA for organizing the LEPC and collecting hazardous materials information. In Illinois, the SERC is IEMA.
SIP: Shelter In Place. Remaining in a location where hazardous materials are in the environment, while taking precautions to minimize exposure to those materials. See the SiP section below for details.
SIRT: [IL] State Interagency Response Team.
Solvent / solute / solution / soluble: A solvent is a substance that dissolves another substance or substances to form a solution (a homogeneous mixture). The solvent is the component in the solution that is present in the largest amount, or is the one that determines the state of matter of the solution. Solvents are often, but not always, liquids. They can also be gases or solids. The material dissolved in the solvent is called the "solute". Together, the solvent and solute comprise the "solution". A solute substance that readily dissolves in a particular solvent is said to be "soluble" in that solvent. For example, a substance that dissolves in water is said to be "soluble in water", or more simply "water soluble".
SPEGL: Short–term Public Emergency Guidance Level. An acceptable concentration of a substance for unpredicted, single, short–term exposure of the general public to that substance in emergencies. Developed by National Academy of Sciences, NRC.
Staging area: The location designated by the ICS Liaison Officer or Incident Commander where personnel and equipment not immediately needed for an emergency response are organized and kept ready for use.
State of matter: For our purposes, one of solid, liquid, or gas. Most substances can exist, depending on temperature and pressure, in any one or a combination of these states.
STEL: Short–Term Exposure Limit. The concentration of a substance to which people can be exposed continuously for a "short" period of time without suffering from (a) irritation, (b) chronic or irreversible tissue damage, or (c) narcosis of sufficient degree to increase the likelihood of accidental injury or to impair self–rescue.
Sublime: To change state directly from a solid to gas, without passing through a liquid phase.
Superfund: Set up by the US Congress to fund remediation of hazardous waste conditions. For connections to LEPC, see under headings CERCLA and SARA.
Synergistic: A biologic response to multiple substances where one substance increases the effect of another substance. The combined net effect of the substances acting together is greater than the sum of the effects of the substances acting by themselves [compare additive effect and antagonistic effect].


Tachycardia: Increased heart beat, generally meaning more than 100 pulses per minute. Compare to bradycardia.
TDLO: Toxic Dose LOw; the lowest dose at which toxicity occurred.
Teratogen: A substance that causes defects in development between conception and birth. A teratogen is a substance that causes a structural or functional birth defect.
Tier II Report: The Emergency and Hazardous Chemical Inventory form that must be submitted annually under EPCRA regulations (§312) by any facility that has on hand substantial quantities — as defined by the EPA — of hazardous substances. The form lists the substances and quantities, and provides employee contact information. Copies of this form go to the LEPC, the SERC and the local fire department. A Windows program, tier2submit.exe, allows this report to be created easily.
TIH: Toxic by inhalation. Describes a gaseous material that is toxic when breathed. Some water-reactive materials (WRM) that are TIH produce additional TIH substances when exposed to water (e.g. BrFl₃, SOCl₂).
TLV^®: Threshold Limit Value. The ACGIH guideline for the atmospheric concentration of a substance to which nearly all U.S. workers can be exposed day after day without adverse effect. There are more than 700 of these.
TMDL: Total Maximum Daily Load. The largest amount of a substance that may be added to a waterway in one day under the provisions of the National Clean Water Act. This value is determined by the state, with oversight by the EPA.
Toxic[ity]/Toxin: Toxic means capable of causing harmful effects to living organisms under certain circumstances of exposure. Roughly equivalent to "poisonous". Toxicity is the degree to which a substance is toxic. A toxic substance is often called a "toxin". A substance is considered to be a toxin if there is evidence that it is a health hazard at specified doses, and it is listed in the RTECS.
TPQ: Threshold Planning Quantity (of an EHS.) The maximum amount, in pounds, of an EHS present at any one time at a facility during the year. Depending on the substance, this amount can range from a lower quantity of 1 to 1000 pounds to an upper quantity of 10 000 pounds. If a facility has any EHS present in an amount greater than the established TPQ, the facility must comply with reporting provisions of EPCRA §301, §302, and §303
TRI: Toxics Release Inventory. EPCRA §313. Requires certain facilities to submit a form annually to the EPA and SERC covering releases and waste management of toxic chemicals. The information is available to the public , although it is not up to date: there is around a two year delay in posting of results.
TSCA: Toxic Substances Control Act, 40 CFR 700–799. Gives the EPA jurisdiction to control the use of and exposure to industrial chemicals not subject to other laws.
TWA: Time–Weighted Average. An arithmetic mean value taken over a time period. Multiply each value by the number of time units in which that value occurred, sum the products, and divide the sum by the total number of time units.


UCS: Unified Command Structure. An expanded version of the concept of ICS. It is a system for managing a multi–jurisdictional emergency response situation, made up of key officials from each affected jurisdiction plus the ICS functional departments. A UCS is led by a Unified Commander (UC).
UEL: Upper Explosive Limit. The atmospheric concentration of a flammable hazardous material above which it is too rich in fuel (deficient in oxygen) to be subject to explosion. See also LEL. Note that ventilation of an area which contains a flammable substance above this concentration can bring the concentration into the explosive range, and result in a sudden fire or explosion. Known also as Upper Flammable Limit (UFL).


v/v: A label attached to the concentration value of a substance in percent, ppm, ppb or the like, that indicates the value is concentration "by volume": so many volume units of the substance as a fraction of the total volume of the mixture.
Ventillation: Replacement of contaminated air with air from the surrounding area. Typically, the replacement air will be cleaner and/or contain more oxygen.
VOAD: Voluntary Organizations Active in Disaster. Generally refers to the state affiliates of NVOAD. Illinois has an NVOAD state member.
VOC: Volatile Organic Compounds. Organic compounds with a "fast" evaporation rate into the air. VOCs include substances such as benzene, toluene, methylene chloride, and methyl chloroform.
Volatilization: A general term for the state change of a substance into a gas. It covers both evaporation (from liquid to gas), and sublimation. A substance is "volatile" if it readily undergoes volatilization at ordinary temperatures.


w/w: A label attached to the concentration value of a substance in percent, ppm, ppb or the like, that indicates the value is concentration "by weight": so many mass units of the substance as a fraction of the total mass of the mixture.
WEEL: Workplace Environmental Exposure Level. Guidlines of the American Industrial Hygiene Association for substances that do not currently have a TLV established.
WMD: Water Management District.
WMD: Weapons of Mass Destruction.
WRM: Water-Reactive Material.


Z list: OSHA's Toxic and Hazardous Substances Tables Z-1, Z-2 and Z-3 of air contaminants. These tables give the TWA, STEL and Ceiling values for the listed materials.
Zero air: Air purified to a concentration of less than 0.1 ppm total hydrocarbons.

LEPC Location	LEPC Web Site link (URI)
Chicago	http://www.ci.chi.il.us/LEPC/
Green County WI	http://www.gcemergsvcs.com/news.htm
Jo Daviess County	http://www.roysterclark.com/jdclepc/index3.htm
Kane County	http://www.kcoem.org/lepc/
Lake County IN	http://lepc.co.lake.in.us/
Mason County	http://www.lepc911esda.com/
McHenry County	http://www.co.mchenry.il.us/Common/CountyDpt/Esda/LEPC/lepc.asp
Will County	http://www.lincolnnet.net/users/lrwcoem/http/
Winnebago County	http://www.winn-lepc.org/

CERP Appendices

Appendix A — Glossary

Appendix B — Additional Useful Links

EHS

LEPC web sites around this area

LEPC Nationwide

Illinois Homeland Security

Appendix C — Shelter In Place