Absorption - Taking in toxic material by contact with the skin.

Acids - A class of compounds that can be corrosive when concentrated. Weak acids, such as vinegar and citric acid, are common in foods. Strong acids, such as muriatic (or hydrochloric), sulfuric and nitric acid have many industrial uses, and can be dangerous to those not familiar to handling them. Acids are chemical "opposites" to bases, in that they can neutralize each other.

Acute Hazards - Hazards associated with short-term exposure to relatively large amounts of toxic substances.

Alkaline - Having the properties of a base, a pH greater than 7. Usually used as an adjective, i.e. "alkaline soil".

Alpha particle - A positively-charged particle emitted by radioactive atoms.Alpha particles travel less than one inch in the air and a thin sheet of paper will stop them. The main danger from alpha particles lies in ingesting the atoms which emit them. Body cells next to the atom can then be irradiated over an extended period of time, which may be prolonged if the atoms are taken up in bone, for instance.

Ambient Temperature - The normal temperature of the environment.

Bases - A class of compounds that are "opposite" to acids, in that they neutralize acids. Weak bases are used in cooking (baking soda) and cleaners. Strong bases can be corrosive, or "caustic". Examples of strong bases that are common around the house are drain cleaners, oven cleaners and other heavy duty cleaning products. Strong bases can be very dangerous to tissue, especially the eyes and mouth.

Beta Particals - Very high-energy particle identical to an electron, emitted by some radioactive elements. Depending on their energy, they penetrate a few centimeters of tissue.

Bill of Lading - The shipping papers prepared by the shipper for over the road travel. Usually found at drivers side of the cab.

B.L.E.V.E. - Boiling Liquid Expanding Vapor Explosion. A container failure with a release of energy, often rapidly and violently, accompanied by release of gas to the atmosphere, followed by ignition.

Boilover - The violent expulsion of oil and froth from a tank due to the rapid expansion of water into steam when the heat wave in the oil reaches the water layer, usually suspended toward the bottom of the tank of heavy or unrefined oil.

Catalyst - A substance that accelerates chemical change yet is not permanently affected by the reaction

Caustic - The common name for sodium hydroxide, a strong base. Also used as an adjective to describe highly corrosive bases.

Chemtrec - The Chemical Transportation Emergency Center , a telephone hot-line for chemical information and emergency notifications. (1-800-424-9300)

Code of Federal Regulations - (CFR) - The formal name given to those books or documents that contain the specific regulations provided for by the law.

Confinement - Those procedures taken to keep a material in a defined or local area.

Consignee - The person who is to receive a shipment.

Container - Any bag, barrel, bottle, box, can, cylinder, drum, reaction vessel, storage tank, or the like that contains a hazardous material.

Containment - Those procedures taken to keep a material in its container.

Contaminate/Contamination - A substance which poses a threat to life, health, or environment.

Control - The procedure, techniques, and methods used in the mitigation of a hazardous materials incident.

Control Zones - The designation of areas at a hazardous material incident based upon safety and the degree of hazard. For purposes of this document, these zones shall be defined as the hot, warm, and cold zones.

Corrosivity - A characteristic of acidic and basic hazardous wastes. The characteristic is defined by a waste's pH and its ability to corrode steel. A waste is corrosive if it has a pH less than or equal to 2.0 or greater than or equal to 12.5. See pH, acids, bases

Cumulative Impact - The term cumulative impact is used in several ways: as the effect of exposure to more than one compound; as the effect of exposure to emissions from more than one facility; the combined effects of a facility and surrounding facilities or projects on the environment; or some combination of these.

Decontamination (Contamination Reduction) - The chemical and or physical process of reducing and preventing the spread of contamination from persons and equipment used at a hazardous materials incident.

Deflagration - Burning which takes place at a speed below the velocity of sound.

Degradation - A chemical action involving the molecular breakdown of a protective clothing material due to contact with a chemical. The term degradation may also refer to molecular breakdown of the spilled or released material to render it less hazardous.

Emergency - A sudden and unexpected event calling for immediate action.

Emulsifiers - Substances that help in mixing liquids that don't normally mix; e.g., oil and water.

Environment Hazard - A condition capable of posing an unreasonable risk to air, soil quality, and to plants or wildlife.

Flash Point - The lowest temperature at which a liquid generates enough vapor to ignite in air.

Frothover - A steady, slow frothing over the rim of a tank without the sudden violent action that occurs in a boilover.

Fusible Plugs - A safety relief device in the form of a plug of low melting metal. The plugs close the safety relief device channel under normal conditions, and are intended to yield or melt at a set temperature to permit the escape of gas.

Gamma Radiation - A high-energy photon (ray) emitted from the nucleus of certain radioactive atoms. Gamma rays are the most penetrating of the three common types of radiation (the other two are alpha particles and beta particles) and are best stopped by dense materials such as lead.

Half-life - The amount of time that is required for a radioactive substance to lose one-half its activity. Each radioactive substance has a unique half-life. It is also used to describe: the time for a pollutant to lose one half of its concentration, as through biological action; and the time for elimination of one half a total dose of a drug from a body.

Hazard/Hazardous - Capable of posing an unreasonable risk to health and safety (DOT). Capable of doing harm.

Haz-Mat Branch - That branch of an overall Incident Management System (IMS) that deals with the technical aspect of the incident.

Haz-Mat Branch Officer - The person responsible for the management of the Haz-Mat Branch.

Hazardous Material - A substance (gas,liquid, or solid) capable of creating harm to people, people, property, and the environment.

Hazardous Material Classification - The general grouping of hazardous materials into nine categories identified by the United Nations Hazard Class Number System, including;

1. Explosives

2. Gases ( Compressed, Liquefied, Dissolved )

3. Flammable Liquids

4. Flammable Solids

5. Oxidizers/Organic Peroxides

6. Poisonous Materials

7. Radioactive Materials

8. Corrosive Materials

9. Dangerous Substances - ORMs

(Other Regulated Substances)

Heavy Metals - A group of elements (such as chromium, lead, copper and zinc) that can be toxic at relatively low concentrations and tend to accumulate in the food chain

IDLH - Immediately Dangerous to Life and Health. The maximum level of concentration from which one could escape within thirty minutes without any impairing symptoms or irreversible health effects.

Incident - The release or potential release of a hazardous material into the environment.

Incident Management System - An organized system of roles, responsibilities, and standard operating guidelines used to manage and direct emergency operations.

Incident Commander - The Incident Commander (IC) is the designated officer of the jurisdictional fire department responsible for all decisions relating to the management of the incident. The IC is in charge of the incident.

Ingestion - The taking in of toxic materials through the digestive tract.

Inhalation - The taking in of toxic materials by breathing through the nose or mouth.

Irritant - A chemical that can cause temporary irritation at the site of contact.

Labels - Rectangle or diamond shaped labels required on individual shipping containers that are smaller than 640 cu. ft.

Material Safety Data Sheets (MSDS ) - Provided by manufacturers and compounders (blenders) of chemicals, with minimum information about chemical composition, physical and chemical properties, health and safety hazards, emergency response, and waste disposal of the material as required by OSHA 29 CFR 1910.120.

Mitigation - Actions taken to prevent or reduce product loss, property damage, human injury or death, and environmental damage due to the release or potential release of hazardous materials.

Monitoring Equipment - Instruments and devices used to identify and quantify contaminates in order to determine the level of personal protection needed.

N.O.S. - Not Otherwise Stated or Not Otherwise Specified.

O.R.M. - (Other Regulated Material) Materials that do not meet the definitions of hazardous materials, but posses enough hazardous characteristics that they require some regulation.

Overpacking - Process used for isolating waste by jacketing or encapsulating waste-holding containers to prevent further spread or leakage of contaminating materials. Leaking drums may be contained within oversized ones as an interim measure prior to removal and final disposal.

Particulates - Small solid or liquid particles, especially those in the emission gases of incinerators, boilers, industrial furnaces or in exhaust from diesel and gasoline engines. Particles below 10 microns (10 one-millionths of a meter, 0.0004 inch) in diameter are considered potential health risks because, when inhaled, they are taken deep into the lungs. Regulations require that an incinerator emit no more than 180 milligrams of total particulates per dry standard cubic meter per minute.

Penetration - The movement of a material through a suit's closures, such as zippers, buttonholes, seams, flaps, or other design features of chemical protective clothing, and through punctures, cuts, and tears.

Permeation - A chemical action involving the movement of chemicals, on a molecular level, through intact material.

pH - A convenient way of describing the strength of an acidic or basic aqueous solution. The values range from 0 to 14, with a pH of 7 corresponding to neutral. As the pH number becomes smaller by one unit, the acidity increases by a factor of 10 (for 2 units, it changes by 100, and so on). Likewise, as the pH number increases by one unit, the alkalinity (basic property) increases by a factor of 10, etc.; tap water may lie in a region from above 6 to below 8. Strongly acidic waste solutions (pH less than 2) and strongly basic ones (pH greater than 12.5) are defined as hazardous wastes because of their corrosive effect on metals and on skin.

Placards - 10 3/4" square diamond markers required on the transporting vehicle such as a truck or tank car, or a freight container 640 cu. ft. or larger.

Plume - A body of contaminate flowing from a specific source. The movement of the groundwater is influenced by such factors as local groundwater flow patterns, the character of the aquifer in which the groundwater is contained, and the density of contaminants. A plume may also be a cloud of smoke or vapor. It defines the area where exposure would be dangerous. 

Protective Clothing - See Hazardous Materials Guidelines.

Radiation - The process of emitting energy in the form of energetic particles (such as alpha particles or gamma radiation), light or heat.

Reactive - A class of compounds which are normally unstable and readily undergo violent change, react violently with water, can produce toxic gases with water, or possess other similar properties.

Resources - All of the immediate or supportive assistance available to help control an incident; including personnel equipment, control agents, agencies, and printed emergency guides.

Response - That portion of emergency management in which personnel are involved in directly dealing with control of a hazardous materials incident.

Sampling - Sampling is the process of collecting a representative amount of air, water, soil, product, chemical or hazardous material for analytical purposes.

Secondary Containment - A structure designed to capture spills or leaks, as from a container or tank. For containers and aboveground tanks, it is usually a bermed area of coated concrete. For underground tanks, it may be a second, outer, wall or a vault.

Solidification - Mixing additives, such as fly ash or cement, with soil containing hazardous chemicals, especially metals, to make it more stable.

Solubility - A measure of the amount of a substance that will dissolve in another substance. Water solubility means a substance will dissolve in water.

Specific Gravity - The weight of a substance as compared to the weight of an equal volume of water (for solids and liquids) or an equal volume of air (for gases).

Stabilization - The period of an incident where the adverse behavior of the hazardous material is controlled.

Standard Transportation Commodity Code - ("STCC NUMBER") - A listing of code numbers for categories of articles being shipped, in general use by carriers. (Rail Only)

TLV - (Threshould Limit Value) Public health exposure level set by the National Institute for Occupational Safety and Health for worker safety. It is the level above which a worker should not be exposed for the course of an eight-hour day, due to possible adverse health effects.

Toxicity - The ability of a substance to cause injury to biologic tissue.

Toxic Materials - Substances that can be poisonous if inhaled, swallowed, or absorbed into the body through cuts or breaks in the skin.

Vapor - Gas given off, with or without the aid of heat, by substances that under ordinary circumstances are either solid or liquid.

Vapor Density - A measurement of the relative density of a vapor as compared with air. A figure of less than 1 indicates a vapor that is lighter than air. A figure that is more than 1 indicates a vapor that is heavier than air.

Vaporization - The process of changing from liquid to vapor.

Vapor Pressure - The pressure exerted by a liquid vaporizing in a closed container. This pressure will vary with different liquids and will vary depending upon temperature.

Vapor Space - Space left empty inside a tank containing liquefied gas to allow for expansion of the gas due to normal changes in temperature.

Viscosity - The flow resistance of a liquid. This characteristic increases or decreases with the temperature of the liquid. Low viscosity liquids have little adhesive qualities and hence flow freely.

Volatile - Describes substances that readily evaporate at normal temperatures and pressures.

Water Reactive Substances - Generally flammable solids, that will react in varying degrees when mixed with water or when they come in contact with humid air.

Water Solubility - The ability of liquid or solid to mix with or dissolve in water.

Waybill - The shipping paper prepared by the railroad from a bill of lading. Waybills generally accompany a shipment and are carried by the conductor. Also a consist and wheel report are available on a rail car shipment.

Weak Seam - In oil tanks, a special roof-to-shell seam attachment that is designed to give way under extreme pressure and release vapor from the vapor space.