Today is Tuesday, Nov. 13, 2018

Department of Environmental Health

Training Programs

Glossary and List of Acronyms



Absorption – materials may be taken into the body (absorbed) through the skin or lungs.

Acid – any chemical with lower than 7 pH (see also pH).                                             

Acute effect – a health effect which develops rapidly. Exposure to carbon monoxide may cause a person to pass out, an acute effect.

Additive effect – one in which the combined effect of two chemicals is equal to the sum of the agents acting alone.

Administrative controls – policies and practices written before work begins to minimize exposure to chemical and physical hazards.

Adsorption – when a chemical becomes attached to another material, for example, soil.

Aerosol – Liquid or solid particles in the air. Aerosols include dust, mists, fog, and fumes.

Air Purifying Respirator (APR) – protective mask which filters air and toxic materials through filters.

Alkali – any chemical with a high pH that in water solution is irritating or caustic to the skin. Strong alkalies in solution are corrosive to the skin and mucous membranes (See also pH.)

Alpha – positively charged radiation particle capable of traveling only a few inches in air.

Alveoli – the small air spaces deep in the lung where oxygen goes into the blood.

Ambient Temperature – Temperature of the surrounding air or other medium.

American Conference of Governmental Industrial Hygienists (ACGIH) – An organization of professional personnel in governmental agencies or educational institutions engaged in occupational safety and health programs.  ACGIH develops and publishes recommended occupational exposure programs.  ACGIH develops and publishes recommended occupational exposure limits (See TLV) for chemical substances and physical agents.

Anhydrous – free from water.

Antagonism – the situation in which two chemicals, when introduced interfere with each other’s actions or when one chemical interferes with the action of the other.

Asphyxiant – a vapor or gas which can cause unconsciousness or death by suffocation (lack of oxygen). Asphyxiation is one of the principal potential hazards of working in confined spaces.

Atmosphere – Thin layer of gases that covers the Earth’s surface.

Atmospheric Transport – The transport of pollutants away from their source through the atmosphere. Both local and long-range transport is observed. Distance depends on characteristics of chemical, source emissions, and weather patterns.

Atmospheric Deposition – The transport of pollutants away from their source through the atmosphere. Both local and long-range transport is observed. Distance depends on characteristics of chemical, source emissions, and weather patterns.



Base – A liquid or solid which has pH greater than 7.

Beta – a negatively charged radiation particle.

Bioaccumulative – Substances that increase in concentration in living organisms as they take in contaminated air, water or food because the substances are veryslowly metabolized or excreted.

Biological Magnification – Refers to the process whereby certain substance such as pesticides or heavy metals move up the food chain, work their way into rivers or lakes, and are eaten by aquatic organisms such as fish, which in turn are eaten by large birds, animals or humans. The substance becomes concentrated in tissues or internal organs as they move up the chain.

Biosphere – All living organisms on the earth.

Boiling point – temperature at which a liquid changes to a vapor. Flammable materials with low boiling points generally present special fire hazards.

Boiling Point – Temperature at which a liquid changes to a vapor. Flammable materials with low boiling points generally present special fire hazards.

BPA – bis-Phenol A , a synthetic estrogen, and a component of polycarbonate.

Buddy system – a work practice in which workers team up in pairs during work activities.

Bung – the cap or plug that fits into the holes in a drum.



Carcinogen – a substance which can cause cancer.

CAS Number – a unique number assigned to a chemical by the Chemical Abstract Service.

Catalyst – a substance that speeds up a chemical reaction.

cc – cubic centimeter, a metric measurement about the size of a sugar cube.

Ceiling (C) – the maximum allowable exposure limit for an airborne substance, not to be

exceeded during the shift.

Central Nervous System (CNS) – the part of the nervous system protected by the skull and the spinal column.

Chemical cartridge – a filtering device which is attached to an air-purifying respirator.

Chemical hazard – Any chemical, chemical compound, or mixture of compounds that as a result of its chemical properties poses a danger to living organisms and materials in the environment.

Chemical resistance – material which prevents chemicals from permeation.

Chemical treatment – treating waste to reduce its toxicity in preparation for disposal.

Chronic effect – a health effect which develops slowly over a long period of time.

Compustible Liquids – A term used by the National Fire Protection Association (NFPA), the Department of Transportation (DOT), and others to classify certain liquids that will burn, on the basis of flash points. BothNFPA and DOT generally define combustible liquids as having a flash point of 100oF (37.8oC) or higher. They do not ignite as easily as flammable liquids; however, they can be ignited under certain circumstances and must be handled with caution.

Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) – authorized government money for clean-up of abandoned hazardous waste sites, clean-up and emergency response to transportation incidents involving chemical releases, payment to injured or diseased citizens, etc. It was amended in 1986.

Concentration – the amount of one material in another.

Confined space – any area not intended for human occupancy that can be entered and has limited natural ventilation, making it easier for gases or vapors to accumulate.

Contaminant – A substance present in an environment, which causes some deviation from the normal composition of the environment.

Corrosive – a liquid or solid that eats away another material or substance with which it comes in contact.

cu m (or m3) – cubic meter.



Decibels (dB) – a unit of measurement to detect noise levels.

Decomposition – the breakdown of a material (by heat, chemical reaction, decay, or other processes).

Decontamination – the chemical or physical process of reducing and preventing the  spread of contamination from persons and equipment used at a hazardous materials  incident.

Decontamination line – a line set up with stations for decontamination procedures between the Exclusion Zone and the Support Zone.

Degradation – method of decontamination in which the chemical structure of the hazardous material is altered by mixing with another reactive chemical to lessen the danger of the hazardous material.

Demand regulator – reduces tank pressure to provide air when the wearer inhales.

Density – A measure of how heavy a specific volume of a solid, liquid or gas is in comparison to water.

Department of Transportation (DOT) – regulates shipments and transfer of hazardous materials.

Dermal toxicity – Adverse effects resulting from skin exposure to a substance.

Dermatitis – redness or irritation of the skin.

Dilution – method of reducing the concentration of a contaminant to a safe level.

Dose – the quantity of a chemical taken into the body.

Dose response – the relationship between the amount of the chemical and the amount of response in humans or animals.

Dose response curve – a graph that shows how much of the chemical dose causes an observed effect.

Drum grappler – a device designed to be attached to mechanical equipment for the purpose of enabling the equipment to be used for drum handling.

Dust – Solid particles in the air generated by handling, crushing, or grinding.

Dyspnea – Shortness of breath.



Ecology – of the relationships between living organisms and their physical environment.

Ecosystems – An assembly of interacting organisms and their environment in which materials are interchanged in a largely cyclical manner. An ecosystem has chemical, physical, and biological components.

Emergency – an unexpected or unplanned event requiring remedial action.

Emergency response plan – written descriptions of planned actions and personnel respon­sibilities for emergency response actions.

Engineering control – substitution, isolation, and ventilation methods used to reduce the level of the containment at the source.

Environmental justice – Fair treatment and equitable application and enforcement of environmental laws, regulations, and policies to all people and their communities. It includes effective protection from environmental hazards and public health hazards for all people regardless of race, color, national, tribal, or ethnic origin; or income.

Environmental Protection Agency (EPA) – federal agency concerned with environmental air, water, and land quality,

Evaporation rate – how fast a liquid enters the air when compared with a known material. The evaporation rate can be useful in the evaluation of the health and fire hazards of a material. The known material is usually butyl acetate, with a vaporization rate designated as 1.0. Vaporization rates of other solvents or materials are then classified as:

  • FAST – evaporating if greater than 3.0.
  • MEDIUM – evaporating if 0.8 to 3.0.
  • SLOW – evaporating if less than 0.8.

Exclusion zone (Hot Zone) – the area where the hazard is present-contaminated area.

Exposure – the concentration of a material in the air to which a worker can come into contact. Usually, exposure is measured near the nose of the worker.

Exposure assessment – Determination of how much of each chemical to which people may be exposed.



Flammable – a liquid with a flash point below 100 oF (37.8 oC) – Class I A: those having flash points below 73 oF and having a boiling point below 100 oF; Class I B: those having flash points below 73 oF and having a boiling point at or above 100 oF; Class I C: those having flash points at or above 73 oF and below 100 oF.

Flash Point – the temperature at which a liquid will give off enough flammable vapor to burn. There are several flash point test methods, and flash points may vary for the same mate­rial depending on the method used; so the test method is indicated when the flash point is given.



Generic name – The name used to identify a material, regardless of which company manufactures it. For example, crank case oil.

Geosphere – Consists of the solid earth, including the soil.

Gram (gm) – a metric unit of weight. One U.S. ounce is about 28.4 grams.

Green Chemistry – A program to promote the reduction or elimination of the use or generation of hazardous substances during the manufacture of chemicals.



Hazardous material – to be considered hazardous, a waste must be on the list of specific hazardous waste streams or chemicals, or else it must exhibit one or more of certain specific characteristics including flammability, corrosivity, reactivity, and toxicity. The definition excludes household waste, agricultural waste returned to the soil, and mining overburden returned to the mine site. It also excludes all wastewater returned directly or indirectly to surface waters. However, hazardous waste may physically be in the liquid state.

Hazardous substance – A material that my pose a danger to living organisms, materials, structures or the environment by explosion or fire hazards, corrosion, toxicity to organisms or other detrimental effects.

Hazardous waste – A legal term. (To be considered hazardous, a waste must be on the list of specific hazardous waste streams or chemicals; otherwise it must exhibit one or more of certain specific characteristics including ignitability, corrosivity, reactivity, and toxicity. The definition excludes household waste, agricultural waste returned to the soil, and mining overburden returned to the mine site. It also excludes all wastewater returned directly or indirectly to surface waters. However, hazardous waste may physically be in the liquid state.)

Hazardous waste operations and emergency response (HAZWOPER) – OSHA standard which was developed to protect hazardous waste personnel and emergency response personnel.

Hazards – the inherent characteristics of a material that may cause incapacitation, injury or mortality by contact, inhalation, or ingestion.

HAZCOM (1910.1200) – OSHA hazard communication standard.

Heat exhaustion – prolonged exposure to intense heat exceeds the body’s ability to cool down, causing excessive sweating and sodium deficiency.

Heat stroke – a life-threatening condition during prolonged exposure to intense heat when the body is unable to sweat; extremely high body temperature and collapse may result.

Heavy metals – the major toxic metals.

Hematotoxin – toxic to the blood or organs where blood is made.

Hepatotoxin – toxic to the liver.

Hydrosphere – Contains the earth’s water.



Immediately Dangerous to Life and Health (IDLH) – any condition which may result in dam­age to health which cannot be repaired. IDLH situations include explosive and oxygen-deficient environments and the presence of Class A poisons or substances which can be absorbed through the skin.

Impervious – Incapable of being penetrated. Used to describe a material which a chemical cannot go through. Frequently used to describe gloves.

Incident commander – person in charge of on-site management of all activities at a hazard­ous materials emergency.

Incident Management System (IMS) – an organized system of personnel and delegation of responsibilities which controls the response to an emergency.

Incompatible – materials which could cause dangerous reactions from direct contact with one another.

Incompatible chemicals – chemicals which produce a negative reaction when mixed.

Ingestion – taking a substance in through the mouth.

Inhalation – Breathing in through the mouth or nose a substance in the form of a gas, vapor, fume, mist, or dust.

Irritant – a substance which causes an inflammatory response when brought into contact with the eyes, skin, or respiratory system.

Isolation – method of decontamination in which contaminated equipment and materials are bagged or covered and set aside, usually for subsequent shipment to an approved landfill for disposal.






Kg – Kilogram; a metric unit of weight equal to 1000 grams, about 2.2 U.S. pounds.



Latency – the time interval between exposure to and the development of a disease.

Leachate – liquid released into soil from a land disposal facility. Leachate is generated when water enters a landfill, migrates through it picking up soluble materials, and seeps into the soil.

Led poisoning – Primary sources of lead exposure for most children are:

  • Deteriorating lead-based paint
  • Lead contaminated dust
  • Lead contaminated residential soil

Lethal – causing death.

Lock-out – a procedure to prevent use of any equipment which should not be used, generally tagged and locked closed or off.

Lower explosive limit – the lowest concentration (lowest percentage of the substance in air) that will produce a flash of fire when an ignition source (heat, arc, flame) is present.



M – meter; a metric unit of length equal to about 39 inches

Main-line valve – controls air flow to the regulator on supplied-air respirators.

Manifest form – required by EPA to track hazardous wastes.

Material Safety Data Sheet (MSDS) – informational sheet which is sent with hazardous ma­terials. Lists: chemical properties, emergency response, reactivity data, control measures, safe handling procedures, and manufacturer.  In the 2012 update to the OShA Hazard Communication Standard, MSDS was changed to SDS, with specification that the information was a specific order.

Melting point – the temperature at which a solid substance changes to a liquid state. For mixtures, a melting range may be given.

Metabolism – the chemical reactions that go on in the body to maintain life.

Microorganisms – Bacteria, fungi, protozoa, and algae- are living catalysts that enable a vast number of chemical processes to occur in water and soil.

Milligrams per cubic meter (mg/m3) – unit of measurement generally used to weigh fibers. One U.S. gram is about 1,000 milligrams.

Monitoring – measuring concentrations of substances in the workplace.

Morbidity – non-fatal disease from an exposure.

Mortality – death from an exposure.

Mutagen – a substance which can change the genetic material in a living cell.



National Fire Protection Association (NFPA) – produces many standards, including the four-color diamond used on labels to indicate hazard. Health, fire, and instability hazards are rated from 0 (none) to 4 (extreme). The Health rating is in the blue section, Fire in red, and Instability in yellow. The white section is reserved for other Special Hazards (for example, radiation: do not use water, or fire.)

National Institute for Environmental Health Sciences (NIEHS) – a federal agency respon­sible for issues related to the environment.

National Institute for Occupational Safety and Health (NIOSH) – a federal research agency responsible for issues related to occupational safety and health.

Nephrotoxin – A substance which is toxic to the kidney.

Neurotoxin – toxic to the brain and nerves.

Nuclear Regulatory Commission – responsible for community and worker protection from radiation hazards.



Occupational Safety and Health Administration (OSHA) – a federal agency  responsible for creating and enforcing laws related to occupational safety and health.

Olfactory—relating to the nose or sense of smell.

Oral – taken into the body through the mouth.

Oral toxicity – adverse effects resulting from taking a substance into the body through the mouth.

Oxidation – a reaction in which a substance combines with oxygen, the oxygen being provided by an oxidizer or oxidizing agent.

Oxidizer – a substance that gives up oxygen readily to stimulate the combustion of organic matter.

Oxygen deficient – air which contains less than 19.5% oxygen.

Oxygen enriched – atmosphere containing more than 23.5% oxygen.



Particulates – Tiny solid or liquid particles suspended in air (pollutants can either be adsorbed on the surface or absorbed by the particle); diesel engines are a source of particulates.

Parts per million (ppm) – a unit used to measure particulates.

Penetration – the flow of a chemical through zippers, stitched seams, pores, or imperfections in the material.

Percutaneous absorption – absorption into the skin.

Permeation – process by which a chemical dissolves in or moves through a protective cloth­ing material on a molecular level.

Permissible Exposure Limit (PEL) – the highest level of a substance to which a person can be exposed.

Persistent – Refers to the length of time a compound stays in the environment, once introduced. A compound may persist less than a second or indefinitely.

Personal Protection Equipment (PPE) – Clothing and equipment worn by pesticide mixers, loaders and applicators and re-entry workers, hazmat emergency responders, workers cleaning up, superfund sites (which are worn to reduce their exposure to potentially hazardous chemicals and other pollutants).

Pesticide – A chemical that kills fungi, rodents, weeds, or insects.

pH – applies to liquids. A pH of less than 7 is acid. A pH of 7 is neutral, and a pH of greater than 7 is alkaline or base. A value that represents the acidity or alkalinity of a water solution.

Physical agent – heat, noise, radiation, vibration.

Pollutant – A substance present in greater than natural concentrations as a result of human activity that has a net damaging effect on the environment.

Pollution prevention – Focuses on reducing the generation of pollution and waste by changing or modifying procedures, processes or raw materials.

Polymerization – A chemical reaction in which one or more small molecules combine to form larger molecules.

Pulmonary toxin – toxic to the lungs.



Qualitative fit-test – measures effectiveness of a respirator by exposing wearer to a test atmosphere containing an irritating or smelly substance. Wearer should not be able to detect the substance.

Quantitative fit-test – measures effectiveness of a respirator in preventing substance from entering the facepiece while wearer is in a test chamber. Actual amount of Concentration of substance is measured inside the facepiece of the respirator.



Rad – A measure of radiation energy absorbed by the body.                                

Reactivity – a description of the tendency of a substance to undergo chemical reaction with the release of energy. Undesirable effects such as pressure build-up, temperature increase, or formation of noxious, toxic, or corrosive by-products may occur because of the reactivity of a substance to heating, burning, direct contact with other material, or other conditions found in use or in storage.

Relative Gas Density –  the weight of a vapor or gas compared to the weight of an equal volume of air; an expression of the density of the vapor or gas. Materials lighter than air have vapor densities less than 1.0. Materials heavier than air have vapor densities greater than 1.0.

REM – a measure of radiation dose from Roentgen Equivalent Man.                                     

Renal – pertaining to the kidney.                                                                           

Residual volume (RV) – the amount of air remaining in the lung after maximum expiratory effort.

Resources Conservation and Recovery Act (RCRA) – a federal law which regulates man­agement and disposal of hazardous materials and wastes.                          

Risk – exposure to the chance of injury or loss.

Risk assessment – A four-part process that estimates the chance that contact with chemicals from a site or other source will harm people now or in the future. This includes data collection and evaluation, exposure assessment, toxicity assessment and risk characterization. This process tells how great (or small) the risks may be.

Risk characterization – Reveals which chemicals are posing the risks and what the health risks are.

Route of Entry – how material gets into the body: inhaled, ingested, via the skin(dermal) or eye(s), and injection.

Route of exposure – The avenue by which a chemical comes into contact with an organism – e.g., inhalation, ingestion, dermal contact, injection.



Sediments – The layers of relatively finely divided matter covering the bottoms of rivers, streams, lakes, reservoirs, bays estuaries and oceans.


Safety Data Sheets (SDS) – Chemical properties, hazards and exposure controls for materials used at the facility are described in a Safety Data Sheet (SDS, formerly known as the Material Safety Data Sheet, or MSDS). SDSs are required by the OSHA Hazard Communication Standard (29 CFR 1910.1200). To make this safety information more useful, the SDS consists of 16 required sections as shown in the OSHA Quick Card: Hazard Communication Safety Data Sheets, on the next page. Regardless of supplier or manufacturer, the order of the information must be as listed.

Self-contained breathing apparatus (SCBA) – a supplied-air respirator consisting of an oxygen tank, carrying assembly, gauge, safety valve, and full facepiece for use when exposures are unknown or particularly toxic.

Sensitizer – a substance which on first exposure causes little or no reaction but which on repeated exposure may cause a marked response not necessarily limited to the contact site. Skin sensitization is the most common form of sensitization in the industrial setting.

Short-Term Exposure Limit (STEL) – an exposure limit set by ACGIH that sets the maximum concentration that a worker can be exposed to during a 15-minute period.

Solubility – The amount of mass of a compound that will dissolve in a unit volume solution.

Solubility in water – a measure of how much of a material will dissolve in a given volume of water.

Specific gravity – the weight of material compared to the weight of an equal volume of water; an expression of the density (or heaviness) of the material. Insoluble materials with specific gravity of less than 1.0 will float in water; insoluble materials with specific gravity greater than 1.0 will sink in water.

Stability – an expression of the ability of a material to remain unchanged. For MSDS purposes, a material is stable if it remains in the same form under expected and reasonable conditions of storage or use. Conditions which may cause instability (dangerous change) are stated. Examples are temperatures above 150° F or shock from dropping.

Standard Operating Procedures (SOP) – written descriptions of tasks and activities to be followed during work.

Support zone (cold zone)- area where administrative and support functions not requiring respiratory protective equipment are performed.

Synergistic Effect – a combined effect of two or more substances which is greater than the sum of the effect of each.

Systemic – relating to the whole body rather than its individual parts.



Teratogen – a substance or agent to which exposure of a pregnant female can result in changes in the fetus.

Threshold – the lowest dose or exposure to a chemical at which a specific effect is observed.

Threshold Limit Value (TLV) – A term used by the ACGIH to express the airborne concentration of a material to which nearly all persons can be exposed day after day without adverse effects. The ACGIH expresses TLVs in three ways:

(1) TLV-TWA – the allowable time weighted average concentration for a normal 8-hour work-day.

(2) TLV-STEL – the short-term exposure limit, or maximum concentration for a continuous 15-minute exposure period (maximum of four-such periods a day, with at least 60 minutes between exposure periods and provided that the daily TLV-TWA is not exceeded.

(3) TLV-C – The ceiling exposure limit or “the concentration that should not be exceeded during any part of the working exposure . . . a 15-minute period except for those substances which may cause immediate irritation . . .”.

Time-Weighted Average (TWA) – measurement to determine the worker’s average exposure to a substance over a typical 8-hour work shift. The actual exposure is then compared to OSHA standards or professional guidelines.

Toxicity – The adverse effects from exposure.

Toxicity assessment – is how we learn about which illnesses or other health effects may be caused by exposure to chemicals.

Toxic Release Inventory – Database of annual toxic releases from industrial facilities in the United States. It is required by law and compiled and published by the EPA. It includes information regarding toxic chemicals being used, manufactured, treated, transported off site, or released into the environment.

Toxic Substances Control Act (TSCA) – a list of reviewed harmful substances that require precautions and safe work practices by the community as well as the industrial population. effects from exposure.



United Nations Identification Number (UN Number) – A number used internationally to identify a hazardous material.

United States Coast Guard (USCG) – concerned with the transportation of hazardous ma­terials across navigable waterways and other bodies of water.

Unstable – Tending to undergo unwanted chemical changes during normal handling or storage.

Upper Explosive Limit or Upper Flammable Limit (UEL/UFL) – pertaining to a vapor or gas. The highest concentration (highest percentage of the substance in air) that will produce a flash of fire when an ignition source (heat, arc, or fame) is present. At higher concentra­tion, the mixture is too “rich” to burn. Also see “LEL.”

μgm – Microgram; one millionth of a gram.



Vapor – gaseous form of a substance normally in the liquid or solid state at room tempera­ture.

Vapor density – the weight of a vapor or gas compared to the weight of an equal volume of air; an expression of the density of the vapor or gas. Materials lighter than air have vapor densities less than 1.0. Materials heavier than air have vapor densities greater than 1.0.

Vapor pressure – indicates the tendency of a liquid to evaporate into the air.

Ventilation – a form of engineering control that removes airborne contaminants.

Viscosity – the property of liquid; resistance to flow.



Waste profile sheet – a document which is provided by the laboratory that conducted the analysis of the hazardous waste. Describes the physical and chemical properties of the waste sample.