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September 2000

Basic Safety and Health Terms, Definitions and Key Web Sites

This article is the second in a series of articles dedicated to the novice health and safety professional.  Here you will find a helpful glossary of the basic terms used in the health and safety field.  This profession has a very complex language associated with it.  Our goal is to help you better understand the technical terminology. 

The following glossary defines words and terms commonly used by health and safety professionals.  In addition, at the end of the glossary, you will find references to many useful health and safety web sites.


Acclimatization.  The process of becoming accustomed to new conditions (i.e., heat).

ACGIH.  The American Conference of Governmental Industrial Hygienists. 

Action level.  Term used by OSHA and NIOSH to express the level of toxicant which requires medical surveillance, usually one half the PEL.

Acute.  Health effects which show up a short length of time after exposure.

Administrative controls.  Methods of controlling employee exposures by job rotation, work assignment or time periods away from the hazard.

AIHA.  The American Industrial Hygiene Association.

Air-purifying respirator.  Respirators that use filters or sorbents to remove harmful substances from the air.

Air-supplied respirator.  Respirator that provides a supply of breathable air from a clean source outside of the contaminated work area.

Alkali.  A compound that has the ability to neutralize an acid and forma salt (i.e., NaOH or sodium hydroxide referred to as caustic soda or lye).

Amorphous.  Noncrystalline.

ANSI.  The American National Standards Institute develops consensus standards nationally for a wide variety of devices and procedures.

Asbestosis.  A disease of the lungs caused by the inhalation of fine airborne fibers of asbestos.

Asphyxia.  Suffocation from the lack of oxygen.

Atmospheric pressure.  The pressure exerted in all directions by the atmosphere.  At sea level, mean atmospheric pressure is 29.92 inches of mercury (Hg), 14.7 psi or 407 inches of water gage.

Audible range.  The frequency range over which normal ears hear - approximately 20Hz through 20,000 Hz.

Audiogram.  A record of hearing loss of hearing level measured at several different frequencies, usually 500 to 6,000 Hz.

Autoignition temperature.  The lowest temperature at which flammable gas or vapor air mixture will ignite from without the use of a spark or flame.

Benign.  Not malignant.

Benzene.  A major organic intermediate and solvent derived from coal or petroleum.  The simplest member of the aromatic series of hydrocarbons.

Berylliosis.  Chronic beryllium intoxication.

Biohazard.  Biological hazard.  Organisms or products of organisms that present a risk to humans, i.e., blood, body fluids.

Body burden.  The amount of noxious materials in the body at a given time.

Boiling point.  The temperature at which the vapor pressure of a liquid equals atmospheric pressure.

Breathing zone sample.  An air-sample collected in the breathing zone of workers to assess their exposure to airborne contaminants.

Carcinogenic.  Cancer producing

Carpal tunnel.  A passage in the wrist through which the median nerve and many tendons pass to the hand from the forearm.

CAS number.  Identifies a particular chemical, a unique number for that chemical.

Catalyst.  A substance which changes the speed of a chemical reaction but undergoes no permanent change itself.

Caustic.  Something that strongly irritates, burns, corrodes or destroys living tissue. 

Ceiling limit (C).  An airborne concentration of a toxic substance in the work environment, which should never be exceeded.

CFR.  Code of Federal Regulations.  The rules promulgated under U.S. law and published in the Federal Register

Chemical cartridge.  The type of absorption unit used with a respirator for removal of low concentrations of specific vapors and gases.

Chronic.  Persistent, prolonged, repeated.

CNS.  Central nervous system.

Combustible liquids.  Those liquids having a flash point at or above 37.8C (100F).

Confined Space.  An enclosure that is difficult to get out of and limited or no ventilation.  Examples are storage tanks, boilers, sewers and tank cars.

Corrosive.  A substance that causes visible destruction or permanent changes in human skin tissue at the site of contact.

Curie.  A measure of the rate at which a radioactive material decays.

Cyanosis.  Blue appearance of the skin, especially on the face and extremities indicating a lack of sufficient oxygen.

Decibel (dB).  A unit used to express sound power level.

Decontaminate. To make safe by eliminating poisonous or otherwise harmful substances.

Density.  The ratio of the mass to volume.

Dermatitis.  Inflammation of the skin from any cause.

Dosimeter.  An instrument used to determine the full-shift exposure a person has received to a physical hazard.

Dyspnea.  Shortness of breath, difficult or labored breathing.

EAP.  Employee Assistance Program.

Eczema.  A skin disease or disorder.  Dermatitis.

Edema.  A swelling of body tissues as a result of being water-logged with fluid.

Electron.  A minute atomic particle possessing a negative electric charge.

Engineering Controls. Methods of controlling employee exposures by modifying the source or reducing the quantity of contaminants released into the workroom environment.

EPA.  Environmental Protection Agency.

Filter. HEPA.  High efficiency particulate air filter that is at least 99.97 percent efficient in removing particles with a diameter of 0.3 microns(u).

Flammable limits.  The lower flammable limit (LFL or LEL) is the minimum concentration below which propagation of a flame does not occur.  The upper flammable limit (UFL or UEL) is the maximum concentration above which propagation of a flame does not occur.  Usually expressed in percents.

Flammable liquid.  Any liquid having a flash point below 37.8C (100F).

Flash point.  The lowest temperature at which a liquid gives off enough vapor to form an ignitable mixture with air and produce a flame in the presence of an ignition source.

Foot candle.  A unit of illumination.

Fume.  Airborne particulate formed by the evaporation of solid materials, i.e., metal fume emitted during welding.

Fume Fever.  Metal fume fever is an acute condition caused by a brief high exposure to the freshly generated fumes of metals, such as zinc or magnesium or their oxides.

Gage pressure.  Pressure measured with respect to atmospheric pressure.

Galvanizing.  An old but still used method of providing a protective coating for metals by dipping them in a bath of molten zinc,

Grab sample.  A sample which is taken within a very short time period.  The sample is taken to determine the constituents at a specific time.

Hazardous material.  Any substance or compound that has the capability of producing adverse effects on the health and safety of humans.

Hearing conservation.  The prevention or minimizing of noise induced deafness through the use of hearing protection and control methods.

Heat stress.  Relative amount of thermal strain from the environment.

Hepatitis.  Inflammation of the liver.

Hydrocarbons.  Organic compounds composed solely of carbon and hydrogen.

IARC.  International Agency for Research on Cancer.

IDLH.  Immediately Dangerous to Life or Health.

Inert.  Not having active (chemical) properties.

Inorganic.  Term used to designate compounds that generally do not contain carbon.

Jaundice.  Icterus.  A serious symptom of disease that causes the skin and the whites of the eyes to turn yellow.

Latent period.  The time that elapses between exposure and the first manifestation of damage.

LC50.  Lethal concentration that will kill 50 percent of the test animals.

LD50.  The dose required to produce death in 50 percent of the exposed species within a specified time.

Local exhaust ventilation.  A ventilation system that captures and removes the contaminants at the point they are being produced before they escape into the workroom air.

MAC.  Maximum allowable concentration.

Makeup air.  Clean, tempered outdoor air supplied to a work space to replace air removed by exhaust ventilation or some industrial process.

Manometer.  An instrument used to measure pressure.

Melting point.  The transition point between the solid and the liquid state. Expressed as temperature at which this change occurs.

Microbe.  A microscopic organism.

Milligram (mg).  A unit of weight in the metric system.  One thousand milligrams equal one gram.

Milligrams per cubic meter (mg/m3).  Unit used to measure air concentrations of dusts, gases, mists, etc.

Milliliter (mL).  A metric unit used to measure volume.

Mixture.  A combination of two or more substances that may be separated by mechanical means.

MSHA.  The Mine Safety and Health Administration. A federal agency that regulates the mining industry in regards to safety and health.

MSDS.  Material Safety Data Sheet.

Nephrotoxin.  Chemicals that produce kidney damage.

Neurotoxin.  Chemicals which produce their primary effect on the nervous system.

NFPA.  National Fire Protection Association.

NIOSH.  The National Institute for Occupational Safety and Health is a federal agency.  It conducts research on health and safety concerns and trains occupational health and safety professionals.

NRC.  Nuclear Regulatory Commission of the U.S. Department of Energy.

NTP.  National Toxicology Program.

OSHA.  U.S. Occupational Safety and Health Administration.

Particulate.  A small discrete mass of solid or liquid matter.

Pathogen.  Any microorganism capable of causing disease.

PEL. Permissible Exposure Limit.  An exposure limit that is published and enforced by OSHA as a legal standard.

Personal Protective Equipment (PPE).  Devices worn by the worker to protect against hazards in the environment (respirators, gloves, hearing protection).

pH.  Means used to express the degree of acidity or alkalinity of a solution with neutrality measured at seven.

PPB.  Parts per billion.  i.e., 1 drop in 14,000 gallons.

PPM.  Parts per million.  i.e., 1 inch in 16 miles.

Presbycusis.  Hearing loss due to age.

Pulmonary.  Pertaining to the lungs.

Radioactivity.  Emission of energy in the form of alpha, beta or gamma radiation from the nucleus of an atom. 

Reactivity.  A chemical substance's susceptibility to undergoing a chemical reaction or change that may result in dangerous side effects.

Renal.  Having to do with the kidneys.

Respirator.  A device to protect the wearer from inhalation of harmful contaminants.

Routes of entry.  The paths by which chemicals can enter the body.  The three main routes are inhalation, ingestion and skin absorption.

Safety can.  An approved container, of not more than 19L (5 gal) capacity, having a spring closing lid and spout cover, and so designed that it will safely relieve internal pressure when subjected to fire exposure.

Salt.  A product of the reaction between an acid and a base.

Sandblasting.  A process for cleaning metal castings and other surfaces with sand by a high pressure air stream.

SCBA.  Self contained breathing apparatus.

Semicircular canals.  The special organs of balance that are closely associated with the hearing mechanism and the eighth cranial nerve.

Sensitization.  The process of rendering an individual sensitive to the action of a chemical.

Sensitizer.  A material that can cause allergic reactions of the skin or respiratory system.

Shakes.  Workers' name for "metal fume fever".

Shielding. Interposed material (like a wall) that protects workers from harmful radiation released by radioactive materials.

Shock.  Primarily, the rapid fall in blood pressure following injury, operation, or the administration of anesthesia.

Silicosis.  A disease of the lungs caused by the inhalation of silica dust.

Short term exposure limit (STEL).  ACGIH recommended exposure limit.  Maximum concentration to which workers can be exposed for a short period of time (15 minutes) for only 4 times throughout the day with at least one hour between exposures.

Solder.  A material used for joining metal surfaces together by filling a joint or covering a junction.

Solvent.  A substance that dissolves another substance.  Usually refers to organic solvents.

Source.  Any substance that emits radiation.  Usually refers to a piece of radioactive material.

Standard Industrial Classification (SIC) Code.  Classification system for places of employment according to major type of activity.

Sterile.  Free of living organisms.

Suspect carcinogen.  A material which is believed to be capable of causing cancer but for which there is limited scientific evidence.

Symptom.  Any bit of evidence from a patient indicating illness; the subjective feelings of the patient.

Syncope.  Fainting spell.

Systemic.  Spread throughout the body, affecting all body systems and organs, not localized in one spot or area.

Temporary threshold shift (TTS).  The hearing loss suffered as the result of noise exposure, all or part of which is recovered during a time when one is removed from the noise.

Teratogen.  An agent or substance that may cause physical defects in the developing embryo or fetus when a pregnant female is exposed to that substance.

Threshold.  The level where the first effects occur.

Time weighted average concentration (TWA).  Refers to concentrations of airborne toxic materials which have been weighted for a certain time duration, usually 8 hours.

Tinnitus.  A ringing sound in the ears.

TLV. Threshold Limit Value.  A time weighted average concentration under which most people can work consistently for 8 hours a day, day after day, with no harmful effects.

Toxemia.  Poisoning by the way of the blood stream.

Toxicant.  A poison or poisonous agent.

Toxin.  A poisonous substance that is derived from an organism.

Turbidity.  Cloudiness; disturbances of solids (sediments) in a solution, so that it is not clear.

Ulcer.  The destruction of an area of skin or mucous membrane.

Urticaria.  Hives

Vapors.  The gaseous form of substances that are normally in the solid or liquid state (at room temperature and pressure). 

Velometer.  A device for measuring air velocity.

Ventilation.  One of the principal methods to control health hazards, may be defined as "causing fresh air to circulate to replace foul air simultaneously removed".

Vertigo.  Dizziness.

Viable.  Living.

Volatility.  The tendency or ability of a liquid to vaporize. 

Wavelength.  The distance in the line of advance of a wave from any point to a like point on the next wave.

Welding rod.  A rod or heavy wire that is melted and fused into metals in arc welding.

Wet-bulb globe temperature index.  An index of the heat stress in humans when work is being performed in a hot environment.

X-ray.  Highly penetrating radiation similar to gamma rays.  When these rays pass through an object they give a shadow picture of the denser portions.

Key Health and Safety Web Sites

Government Departments and Agencies You Need to Know About

Agency for Toxic Substance and Disease Registry
Access to 120 government agencies
Bureau of Labor Statistics
Centers for Disease Control and Prevention, CDC
Chemical Safety and Hazard Investigation Board
Code of Federal Regulations
Congressional Legislation
DOE Worker Health and Safety Site
Environmental Protection Agency
Federal Aviation Administration
Federal Register
Federal OSHA
Manitoba Workplace Safety and Health Division
Mine Safety Administration
Nat'l Inst. For Occ. Safety & Health
NIOSH - National Institute for Occupational Safety and Health
Nat'l Institute of Health
National Toxicology Program Center
NSSN A National Resource for Global Standards
OSHA Home Page
OSHA Regulations and Compliance Links
U.S. Department of Labor
U.S. Department of Labor-Bureau of Labor Statistics
U.S. DOL Women's Bureau
U.S. Department of Energy- Office of Environmental Safety and Health
U.S. National Library of Medicine

American National Standards (ANSI)
American Society of Heating, Refrigeration and Air Conditioning Engineer (ASHRAE)
Consumer Product Safety Commission
National Fire Protection Association
National Safety Council
National Technical Information Sys.
U.S. Government Bookstores
World Health Organization
Safety Research and Related Resource Information

Health Organizations

American Academy of Physician Assistants in Occupational Medicine
American Association of Occupational Health Nurses
American College of Occupational and Environmental Medicine (ACOEM)
American Conference of Governmental Industrial Hygienists(ACGIH)
American Industrial Hygiene Association
American Red Cross
American Society of Safety Engineers
Canadian Centre for Occupational Health and Safety
National Safety Council
NIOSH - National Institute for Occupational Safety and Health
Society for Women's Health Research
University of California San Diego
Women's Health Issues

Chemical Information
Agency for Toxic Substance and Disease Registry
Environmental Protection Agency Safe Drinking Water
Canadian Center for Occupational Safety and Health
Cornell University MSDS Archive
Material Safety Data Sheets
New Jersey Hazardous Substance Fact Sheets
NIOSH Pocket Guide to Chemical Hazards
NIOSH - National Institute for Occupational Safety and Health
Operation Safe Site an online booklet on Personal Protective Equipment

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