Absorption: a process by which a substance may be incorporated or taken into the body (e.g. through the skin).

Acceptability/Tolerability of Risk: a willingness to live with a risk, in order to secure certain benefits.

Accident: any unplanned, sudden event which causes or is liable to cause injury to people or damage to buildings, plant, material or the environment.

Accumulate: increase, build up.

acfm: actual cubic feet per minute of gas flowing at existing temperature and pressure. (See also scfm.)

ACH AC/H (air changes per hour): the number of times air is replaced in an hour.

Acquired immune deficiency syndrome (AIDS): a fatal disease caused by a virus that destroys the immune system's ability to fight off infection

Acrosome reaction: a chemical change that enables a sperm to penetrate an egg

Acrosome: the packet of enzymes in a sperm's head that allows the sperm to dissolve a hole in the coating around the egg, which allows the sperm to penetrate and fertilize the egg

Acute disease: a disease of short duration that often has sudden severe symptoms.

Acute effect: an immediate, obvious response, usually short-term and often reversible.

Acute hazard: hazard to which a single exposure may cause harm, but which is unlikely to lead to permanent damage.

Acute toxicity: the short-term toxicity of a product in a single dose. Can be divided into oral, cutaneous, and respiratory toxicities.

Administrative controls: controls designed to limit the amount of time a worker spends at a potentially hazardous job.

Adrenal glands: the endocrine gland on top of each kidney

Adsorption: adsorption is a surface phenomenon that some products exhibit, whereby they form a physicochemical bond with substances. Not to be confused with absorption.

Adverse Health Effect: abnormal or harmful effect to an organism (e.g., a person) caused by exposure to a chemical. It includes results such as death, other illnesses, altered body and organ weights, altered enzyme levels, etc.

Aerobic bacteria: the bacterial organisms that require relatively high concentrations of oxygen to survive and reporduce

Aerosol spray: a means of atomizing liquids by propelling them from a pressurized container by a soluble gas.

Affiliates: enterprises in which another enterprise has minority voting rights without effective operational control.

Agglutination: clumping together, as of sperm, often due to infection, inflammation, or antibodies

AIDS (acquired immunodeficiency syndrome): a disease caused by infection with HIV (human immunodeficiency virus) that damages the body's immune system.

Air density: the weight of air in lbs per cubic foot. Dry standard air at T=68 degrees F (20 degrees C) and BP = 29.92 in Hg (760 mm Hg) has a density of 0.075 lb/cu ft.

Air monitoring: the sampling and measuring of pollutants in the air.

Alcohols: a series of hydrocarbon derivatives with at least one hydrogen atom replaced by an -OH group. The simplest alcohols (methanol, ethanol, n-propanol, and isopropanol) are good solvents for some organic soils, notably rosin, but are flammable and can form explosive mixtures with air: their use requires caution and well-designed equipment.

Allergic contact dermatitis: is a type of skin hypersensitivity. Its onset may be delayed by several days to as much as several years, for weaker sensitizers. Once sensitized, fresh exposure to the sensitizing material can trigger itching and dermatitis within a few hours.

Ambient: surrounding, as in the surrounding environment. The medium surrounding or contacting an organism (e.g., a person), such as outdoor air, indoor air, water, or soil, through which chemicals or pollutants can be carried and can reach the organism.

Amenorrhea: absence of menstruation

Ames Test: used to assess whether a chemical might be a carcinogen. It assumes that carcinogens possess mutagenic activity, and uses bacteria and mammalian microsomes to determine whether a chemical is a mutagen. Approximately 85% of known carcinogens are mutagens. The Ames test, therefore, is a helpful but not perfect predictor of carcinogenic potential.

Amniocentesis: the aspiration of amniotic fluid from the uterus, usually performed at three to three and one-half months of pregnancy, to test the fetus for genetic abnormalities

Anaerobic bacteria: bacterial organisms that survive in relatively low oxygen concentrations

Androgens: male sex hormones

Andrologist: a specialist who treats sperm problems

Anemometer: a device that measures the velocity of air. Common types include the swinging vane and the hot-wire anemometer.

Anion: a negatively charged ion.

Anovulation: the absence of ovulation

Antagonism (chemical): when the adverse effect or risk from two or more chemicals interacting with each other is less than what it would be if each chemical was acting separately.

Anthropometrics: the study of human measurements among individuals, the sexes, different generations and different ages, especially on a comparative basis.

Antibodies: substances (proteins) that are produced by the body's immune system as part of its response in fighting infections.

Antibody: a protective agent produced by the body's immune system in response to a foreign substance

Antigen: any substnace that induces the formation of an antibody

Antisperm antibodies: antibodies that can attach to sperm and inhibit movement of sperm or fertilization

Aqueous cleaning: cleaning parts with water to which may be added suitable detergents, saponifiers, or other additives.

Argyria or argyrism: an irreversible blueish-black discolouration of the skin, mucous membranes or internal organs caused by ingestion of, or contact with, various silver compounds.

Artificial insemination (AI): placement of a sperm sample inside the female reproductive tract (See also intracervical insemination, intrauterine insemination, intratubal insemination

Aspiration: suctioning of fluid, as from a follicle

Asymptomatic: without any symptoms

Authoritative Scientific or Regulatory Organization: organizations that either have regulatory authority over a subject (such as control of certain chemicals in certain contexts) or are widely recognized as using the best available scientific practices and peer review processes in developing their policies and recommendations about that subject.

Autoantibodies: antibodies formed against one's own tissues

Autoimmunity: an immune reaction against one's own tissues

Azeotrope: a mixture of chemicals is azeotropic if the vapor composition is identical to that of the liquid phase. This means that the distillate of an azeotrope is theoretically identical to the solvents from which it is distilled. In practice, the presence of contaminants in the solvent slightly upsets the azeotropy.

Azoospermia: absence of sperm

Bacteria: microscopic, single-celled organisms that can cause infections of the genital tract

Basal body temperature (BBT): the temperature taken at its lowest point in the day, usually in the morning before getting out of bed

Bioaccumulation: bioaccumulation is the process by which chemicals concentrate in an organism. For example, DDT concentrates in fish and birds that eat fish. This concentration effect is expressed as the ratio of the concentration of the chemical in an organism (like a fish) to its concentration in the surrounding medium (usually water). Bioaccumulation refers to the uptake of chemicals both from water (bioconcentration) and from ingested food and sediment.  

Biocide: an additive that destroys biological contaminants.

Biodegradable: products in wastewater that can easily be broken down or digested by, for example, sewage treatment.

Biological monitoring: usually consists of blood and urine tests performed to look for traces of chemicals and biological indicators of chemical exposure.

Biomechanics: application of physical laws and engineering concepts to an understanding of how the human body acts and reacts to motion and external forces.

Biopsy: a fragment of tissue removed for study under the microscope

Blood-testis barrier: the barrier that separates sperm from the bloodstream

BOD: biochemical oxygen demand, the amount of oxygen consumed by bacteria and other microorganisms.

Boiling point: the temperature in degrees Fahrenheit or Celsius at which a liquid boils.

Break down: weaken.

Bromocryptine (Parlodel): a drug that reduces levels of the pituitary hormone prolactin

Buffer (solvents): a solution that minimizes changes in hydrogen ion concentration that would otherwise occur as a result of a chemical reaction.

Buffering agent (solvents): drives an acidic or alkaline solution to neutral.

Cancer: cancer is a group of more than 100 different diseases that occur when a cell, or group of cells, grows in an unchecked, uncontrolled, or unregulated manner. It can involve any tissue of the body and can have many different forms in each body area. Most cancers are named for the type of cell or the organ in which they begin, such as leukemia or lung cancer.

Cancer Potency Estimate: an estimate of a chemical's likelihood to cause cancer, generally derived from animal studies and extrapolated to humans.

Cancer Risk Score: how a chemical's estimated cancer risk compares with the cancer risk from other chemicals, after being converted into a common unit of comparison.

Cannula: a hollow tube used, for example, to inseminate sperm artificially

Canopy hood: (receiving Hood). A one-or two-sided overhead hood that receives rising hot air or gas.

Capacitation: the process by which sperm become capable of fertilizing an egg

Capture velocity:. the velocity of air induced by a hood to capture emitted contaminants external to the hood.

Carbon tetrachloride: a chlorocarbon solvent with a high ODP (about 1.1) used primarily as a base material for the production of other chemicals. It is also considered toxic and is a probable human carcinogen (classified as a B2 carcinogen by US EPA). Its use is strictly regulated in most countries.

Carcinogen: a chemical known or believed to cause cancer in humans. The number of known carcinogens is comparatively small, but many more chemicals are suspected to be carcinogenic.

Cardiovascular and Blood Toxicity: the adverse effects on the heart or blood systems which result from exposure to toxic chemicals.

Carpal Tunnel Syndrome: a narrow passageway on the palmar side of the hand through which tendons, nerves, and blood vessels pass. Compression of the median nerve in the carpal tunnel can be caused by swollen tendons, excessive bending of the wrist and items which bend into the palm or wrist. This may result in Carpal Tunnel Syndrome (CTS). CTS can cause pain, numbness, tingling or burning in the thumb and first 2 1/2 fingers. It can be mild or quite debilitating, sometimes requiring surgery.

CAS Registry number: a unique number assigned to a chemical; by the Chemical Abstracts Service.

Catheter: a flexible tube used for aspirating or injecting fluids

Cathode Ray Tube (CRT): the glass picture tube of the VDT (video display terminal).

Cation: a positively charged ion.

Cauterize: to destroy tissue with heat, cold, or caustic substances usually to seal off blood vessels or ducts

Ceiling limit: indicates the maximum concentration of a material that must never be exceeded, not even for an instant. In some countries these are required by law.

Cervical spine: the area of the spine where the neck is.

Cervicitis: inflammation of the cervix

Cervix: the lower portion of the uterus that opens into the vigina

CFC: chlorofluorocarbon.

Chelation: chelation is the solubilization of a metal salt by forming a chemical complex or sequestering. One way of doing this is with ethylenediaminetetra-acetic acid (EDTA) salts, which have a multidentate spiral ligand form that can surround metallic and other ions.

Chemical Carcinogenesis: cancer caused by exposure to a chemical or chemicals.  

Chemical Engineering: chemical Engineering is the study of, design for, and analysis of the composition of substances and materials. In other words, the chemical engineer is trained to understand the components that make up composites and the interactions between these components.

Chemical Industry: enterprises which produce, formulate and/or sell chemical substances, including petrochemicals.

Chemical Interaction: when two or more chemicals interact with each other, resulting in either antagonistic or synergistic effects.  

Chlamydia: a type of bacteria that is frequently transmitted sexually between partners or from an infected mother to her newborn child; the most common sexually transmitted bacterial disease

Chlorocarbon: an organic chemical composed of chlorine and carbon, e.g., carbon tetrachloride.

Chlorofluorocarbon: an organic chemical composed of chlorine, fluorine, and carbon atoms, usually characterized by high stability contributing to a high ODP.

Chorionic villus sampling (CVS): taking a biopsy of the placenta, usually at the end of the second month of pregnancy, to test the fetus for genetic abnormalities

Chromosome: threads of DNA in a cell's nucleus that transmit hereditary information

Chronic disease: a disease lasting a long time, or recurring often.

Chronic effect: an effect that usually appears a long time after the exposure occurred and persists over time.

Chronic hazard: a chemical which has the potential to cause long-term damage to health, often as a consequence of repeated or prolonged exposure to it.

Chronic toxicity: the long-term toxicity of a product in small, repeated doses. Chronic toxicity can often take many years to determine.

Chrysiasis: is the development of a blue-grey pigmentation in skin and mucous membranes. May be caused by exposure to gold compounds.

Civil Engineering: the study of, design for, and analysis of artificial physical structures. Included as a subdiscipline is environmental engineering which deals with water quality and water-based systems. Primarily civil engineers are concerned with stresses, strengths, pressures, and fatigue (of materials and substances).

Cleaning: the removal of soil or unwanted matter from a surface to which it clings.

Clomiphene citrate (Clomid, Serophene): a fertility pill that stimulates ovulation through release of gonadotropins from the pituitary gland

Closed cup (CC): a method used to determine the flashpoint of a liquid or volatile solid.

COD: chemical oxygen demand, a test that measures the potential capacity for a microorganism to react with oxygen.

Code of Practice: a document prepared for the purpose of providing practical advice on preventive strategies. It may contain explanatory information. The preventative strategies outlined in a code of practice do not represent the only acceptable means of achieving a standard to which a code refers.

Colloid: a substance that remains suspended in a solution or fails to settle out of solution.

Colposcopy: examination of the cervix through a magnifying telescope to detect abnormal cells

Comply: obey (in the case of laws).

Composite: a resin combined with another material such as glass fiber in such a way that the resulting product has improved physical properties.

Concentration: the weight of a substance in a given weight or volume of material.

Conception: the moment at which an ovum is fertilized by a sperm and beings to grow; the beginning of a new life; the beginning of a pregnancy.

Condom: a latex (rubber) device that fits over the penis to prevent pregnancy and sexually transmitted infections

Conformal coating: a protective material applied in a thin, uniform layer to all surfaces of a printed wiring assembly including components.

Congenital defect: a birth defect

Congenital: describes a problem present or occurring at birth.

Conization: surgical removal of a cone-shaped portion of the cervix, usually as a treatment for a precancerous condition

Connective Tissue: one of the four basic types of tissue in the body; a material consisting of fibers (e.g., tendons or ligaments) that form a framework to support other body tissues (e.g., muscles).  

Consequence: result of a specific event.

Contact dermatitis: a type of reaction (usually to a chemical substance) resembling an allergy which occurs every time the sensitized worker comes into contact with the irritating substance. Characteristic symptoms are red, blistered, itchy or flaky skin. The reaction is not necessarily confined to the place where the substance touches the skin: the symptoms can occur in other parts of the body as well. (See dermatitis.)

Contaminant: any substance or material in a system (the environment, the human body, food, etc.) where it is not normally found; or, a substance in a system where it is naturally occurring , but found in an unusually high concentration.  

Contractors: includes all contractors and subcontractors.

Contraindication: a reason not to use a particular drug or treatment

Corpus luteum: ("yellow body") formed in the ovary following ovulation, it produces progesterone

Corrosive substance: material that can burn or destroy human tissue on contact and can cause permanent scarring or blindness. A corrosive substance may cause metal containers to weaken and eventually leak or collapse. Both acids and alkaline substances are very corrosive.

Cryocautery: cautery by freezing

Cryptorchidism: failure of one or both testicles to descend into the scrotum

Cul-de-sac: pouch located at the bottom of the abdominal cavity between the uterus and rectum

Culdoscopy: examination of the internal female pelvic organs through an incision in the vigina

Cumulative Drauma Disorder (CTD): a chronic soft tissue problem of the musculoskeletal and peripheral nerve system which develops over a long period of time as a result of repeated physical stresses which have a wear-and-tear effect on body structures (tendons, muscles, etc.).

Cutaneous hazard: a chemical which may cause harm to the skin, such as defatting, irritation, skin rashes or dermatitis.

Cyst: a sac filled with fluid

Danazol: (Danocrine) a synthetic androgen frequently prescribed for endometriosis

De Quervain's Disease: one of the most common tendon disorders of the hand. It develops when the tendons on the side of the wrist and base of the thumb become irritated from repetitive bending of the wrist. Symptoms include pain or tensing of the tendons on the side of the wrist.

Decibels, dB or dB(A): the units in which the intensity of sound is measured.

Defence system: the body's natural defences which help to protect people against many hazards, and help the body heal itself.

Defluxing: the removal of flux residues after a soldering operation. Defluxing is a part of most high-reliability electronics production.

Deoxyribonucleic acid (DNA): the combination of amino acids in the cell's nucleus that make up the chromosomes, which transmit hereditary characteristics

Dermal: referring to the skin. Dermal absorption means absorption through the skin.  

Dermatitis: damage to the skin resulting from any irritating substances. Characteristic symptoms are red, blistered, itchy or flaky skin which usually disappear when the worker stops having contact with the irritating substance. (See contact dermatitis.)

Detergency: lifting soil from a surface by displacing it with surface active materials that have a greater affinity for the surface than they do for the soil.

Detergent: a product designed to render, for example, oils and greases soluble in water, usually made from synthetic surfactants.

Developmental Toxicity: adverse effects on the developing child which result from exposure to toxic chemicals or other toxic substances. Adverse effects can include birth defects, low birth weight, and functional or behavioral weaknesses that show up as the child develops.

Diethylstilbestrol (DES): a synthetic estrogen (originally prescribed to prevent miscarriage) that caused malformations of the reproductive organs in some who were exposed to the drug during fetal development

Dilatation and curettage (D&C): an operaton that involves stretching the cervical opening to scrape out the uterus

Dilution ventilation: (General Exhaust Ventilation). A form of exposure control that involves providing enough air in the workplace to dilute the concentration of airborne contaminants to acceptable levels.

Disease incidence: the rate of new occurrences of a disease.  

Donor insemination: artificial insemination with donor sperm

Dose: the amount of a substance that is actually taken in by the worker's body. The dose depends on how much of the substance the worker is exposed to and how long he or she is exposed.

Dose-Response Assessment/Relationship: the amount of a chemical that an organism (such as a person) is exposed to is called the dose, and the severity of the effect of that exposure is called the response. A dose-response assessment is a scientific study to determine the relationship between dose and response, and how much dose is correlated with how much response.  

Dry cleaning: a common term for cleaning garments in organic solvents as opposed to water.

Dynamic excertion: a muscular action which involves a movement,as opposed to a static (fixed posture) exertion.

Dysfunction: abnormal function

Ear protection: hearing protection, usually ear plugs or ear muffs.

Ecological Health Ranking: how a chemical's adverse effect on plants and animals compares with that of other chemicals in a relative ranking system.  

Ecological Risk Assessment: a process used to estimate how likely it is that there will adverse effects on plants or animals from exposure to chemicals (or to other potential stress, such as the draining of a wetland). The process includes problem formulation, characterization of exposure, characterization of ecological effects, and risk characterization.  

Ecotoxicity: being poisonous or harmful to plants or animals in some degree.  

Ectopic pregnancy: pregnancy located outside of the uterus, most commonly in a fallopian tube

ED50: (Effective Dose 50): the amount of material required to produce a specified effect in 50% of an animal population. (See qualification in the definition of LD50).

Egg donation: donation of an egg by one woman to another who attempts to become pregnant by in vitro fertilization

Egg(ovum): the female reproductive cell

Ejaculate: the sperm-containing fluid released at orgasm

Ejaculatory ducts: the male ducts that contract with orgasm to cause ejaculation

Electrical Engineering: the study of, design for, and analysis of how systems that use or depend upon electrical energy work. This form of engineering has evolved in the past few decades to embrace the evolving realm of high technology computing and hence is sometime referred to as electronic engineering.

Electrocautery: cauterization using electircal current

Electroejaculation: controlled electrical stimulation to induce ejaculation in a man with damage to the nerves that control ejaculation

Electrolytes: compounds that conduct an electric current by the movement of ions.

Electromagnetic radiation: electromagnetic energy which moves through space as waves. VDT's can generate various kinds of electromagnetic radiation. Ionizing radiation, which includes x-rays (high frequency electromagnetic waves), is generated when the electron beam hits the screen. Non-ionizing radiation, which includes very low frequency (VLF) and extremely low frequency (ELF) waves, is generated by the electronic components within the monitor's flyback transformer and the horizontal deflection system (the system that moves the beam back and forth and up and down.)

Elimination: getting rid of (a specific hazard).

Embryo transfer: placing a laboratory-fertilized egg into the uterus

Embryo: an unborn child from the time of conception until the end of its eighth week of growth in the womb, after which time it is called a foetus until the time of its birth.

Embryologist: a specialist in embryo development

Embryotoxins: retard the growth or affect the development of the unborn child. In serious cases they can cause deformities or death. Mercury compounds and certain heavy metals, aflatoxin, formamide and radiation are known embryotoxins.

Emergency Preparedness Plan (or) Emergency Plan: a formal written plan which, on the basis of identified potential accidents together with their consequences, describes how such accidents and their consequences should be handled either on-site or off-site.

Employee: a person who is under a contract of employment with an enterprise, including management.

Emulsifier: a chemical that holds one insoluble liquid in suspension in another, such as oil and water.

Endocrine gland: an organ that produces hormones

Endocrine toxicity: any adverse structural and/or functional changes to the endocrine system (the system that controls hormones in the body) which may result from exposure to chemicals. Endocrine toxicity can harm human and animal reproduction and development.

Endometrial biopsy: removal of a fragment of the lining of the uterus for study under the microscope

Endometriosis: growth of endometrial tissue outside of its normal location in the uterus

Endometritis: inflammation of the endometrium

Endometrium: the inner lining of the uterus

Engineering controls: common control measures including isolation, enclosure and ventilation.

Enterprise: a company or corporation (including transnational corporations) which has operations involving the production, processing, handling, storage, use or disposal of hazardous substances.

Environmental Fate: where a substance ends up after it is released into the environment. Environmental fate depends on many factors, including transport (e.g., wind, runoff) and transformation processes (e.g., degradation).  

Epididymis: the tightly coiled, thin-walled tube that conducts sperm from the testicles to the vas deferens

Epididymitis: inflammation of the epididymis

Epithelial Tissue: one of the four basic tissues of the body. The cell linings covering most of the internal and external surface of the body and its organs, e.g. stomach lining.  

Ergonomics: ergonomics is the study of, design for, and analysis of how systems interact with human beings. The basic objective of ergonomics is to optimize human-system performance without causing undue stress or strain on the human beings involved and without any undue risk of injury or illness. Sometimes called human factors, human factors engineering, and human engineering, this discipline is comprised of safety engineers, industrial engineers, and behavioral psychologists.

Estradiol: the principal estrogen produced by the ovary

Estrogens: female sex hormones

Eutrophication: the enrichment of water with nutrients that increase plant growth.

Evaporate: form a vapour.

Event Tree Analysis: one of several methods of hazard analysis involving inductive determination of pathways of disturbances having led to a hazardous situation.

Event: the realisation of a hazard.

Excessive: above the level of comfort.

Exertion: there are two types: STATIC EXERTION: a muscular action which involves maintaining some part of the body in a fixed posture. For example, when you use a hammer, the muscles in your forearm perform a static exertion to maintain your grip, while your upper arm muscles perform a dynamic exertion to raise and lower the hand and forearm. STATIC WORK: work involving prolonged sitting or standing, or work which requires static exertions (certain limbs or joints are kept in fixed positions for a long time).

Exposure Assessment: identifying the ways in which chemicals may reach individuals (e.g., by breathing); estimating how much of a chemical an individual is likely to be exposed to; and estimating the number of individuals likely to be exposed.

Exposure Potential: an estimate of the total dose of a chemical received by an exposed organism (e.g., a person) or by a population, not just via one pathway or medium but from all likely pathways.  

Exposure: coming into contact with an infectious agent (such as bacteria, fungi, viruses, etc.) or toxic substance (chemicals, etc.).

Facility Planning: (sometimes called Facility Layout) is the study, design, and analysis of the layout of production facilities. The basic principal is to achieve efficient layouts that minimize the amount of ineffective and non-productive movement and handling of materials, equipment, and products.

Fallopian tubes: ducts that pick up the egg from the ovary; where a sperm normally meets the egg to fertilize it

Fan: a mechanical device that moves air and creates static pressure.

Fate and Exposure Modeling: the scientific process used to predict where chemicals "end up" after being released into the environment. For example: a chemical may be emitted into the air, but most of it might end up in groundwater, because of the chemical's particular physical properties.  

Fatigue: there are two types: LOCALIZED FATIGUE: the result of excessive demand on some part of the body. The sensations of localized fatigue include: trembling, weakness and pain, and are frequently caused by sustained static exertions. WHOLE-BODY FATIGUE: the result of excessive movements by many muscle groups during physical activity. The sensations include shortness of breath, rapid heart and overall tiredness.

Fatty acids: the principal part of many vegetable and animal oils and greases, also known as carboxylic acids which embrace a wider definition. These are common contaminants that solvents are used to remove. They are also used to activate fluxes.

Fault Tree Analysis: one of several methods of hazard analysis, involving deductive description of events leading from failures of components to a hazardous situation.

Fecundability: the ability to become pregnant

Fertilization: union of the male gamete (sperm) with the female gamete (egg)

Fetus: the developing baby from the second month of pregnancy until birth

Fibroid (myoma or leiomyoma): a benign tumor of the uterine muscle and connective tissue.

Fimbria: the finger-like projections at the end of the fallopian tube nearest the ovary that capture the egg and deliver it into the tube

Fimbrioplasty: plastic surgery on the fimbria of a damaged or blocked fallopian tube

Flammable liquids — LEL (lower explosive limit) and UEL (upper explosive limit): the lower and upper limits of vapour and air concentration, given as a percentage that can cause an explosion.

Flammable: anything that will ignite easily and burn rapidly. The National Fire Protection Association and the Department of Transportation (DOT) define flammable liquids as those having a flash point less than 100 F and a vapor pressure of not over 40 psia at 100 F.

Flash point of a chemical: the lowest temperature at which a flame will propagate through the vapour of a combustible material to the liquid surface. It should be noted that the source of ignition need not be an open flame, but could equally be, for example, the surface of a hot plate, or a steam pipe.

Fluoroscope: an imaging device that uses X-rays to view internal body structures on a screen

Flux: an essential chemical employed in the soldering process to facilitate the production of a solder joint. It is usually a liquid or solid material, frequently based on rosin.

Foetus (or fetus): the term used to describe the developing human baby from the second month after conception until birth.

Follicle stimulating hormone (FSH): the pituitary hormone that stimulates follicle growth in women and sperm formation in men

Follicle: a fluid-filled sac in the ovary that releases an egg at ovulation

Follicular phase: the pre-ovulatory phase of a woman's cycle during which the follicle grows and high estrogen levels cause the uterine lining to proliferate

Foot candle: the unit of measurement for the amount of light falling upon a surface, A table below a four-bulb fluorescent light will receive about 50-60 foot candles of light. As a rule of thumb, with VDT work, the general workplace light may be best at about 20-30 ft. c. (foot candles) and the task lighting would be best at about 50-70 ft. c.

Frequency: the number of times an action is performed in a given period of time.

Fructose: produced by the seminal vesicles, the sugar that sperm use for energy

Gamete Intra Fallopian Transfer (GIFT): combining eggs and sperm outside of the body and immediately placing them into the fallopian tubes to achieve fertilization

Gamete: a reproductive cell; the sperm in men, the egg in women

Ganglionic Cysts: the tendon linings swell with fluid causing a bump under the skin; this is caused by excessive bending of wrist or other joint.

Gardnerella: a bacteria that may cause a vaginal infection

Gene: a sequence of "DNA" which, as a single functional unit, carries a specific code which determines how a cell grows. Thus it is the genes of each cell which transmit hereditary characteristics or "traits". Genes can be damaged (mutated) or destroyed by certain chemicals and by ionizing forms of radiation.

General ventilation: ventilation designed to keep the workplace comfortable.

Genotoxicity: the adverse health effect a chemical has on genes and chromosomes, primarily gene mutations, chromosome aberrations and changes in chromosome number. Genotoxicity may be indicative of cancer-causing chemicals.  

Gestation sac: the fluid-filled sac in which the fetus develops, visible by an ultrasound exam

GIFT: see Gamete Intra Fallopian Transfer

Gland: an organ that produces and secretes essential body fluids or substances, such as hormones

Glare: unwanted light. It is experienced as a distracting light reflected or given off directly by a light source which can make it difficult to read the screen.

Golfer's elbow (or MEDIAL EPICONDYLITIS): an irritation of the tendon attachments of the finger flexor muscles on the outside of the elbow. It is associated with work requiring repeated or forceful rotation of the forearm and bending of the wrist at the same time.

Gonadotropin releasing hormone (GnRH): the hormone produced and released by the hypothalamus that controls the pituitary gland's production and release of gonadotropins

Gonadotropins: the hormones produced by the pituitary gland that control reproductive function follicle stimulating hormone (FSH) and luteinizing hormone (LH)

Gonads: organs that produce the sex cells and sex hormones; testicles in men and ovaries in women

Gonorrhea: a sexually transmitted infection caused by bacteria Neisseria gonococcus that can lead to infertility

Granuloma: a ball of inflamed tissue, commonly formed after vasectomy due to sperm leaking from the vas deferens

Greenhouse effect: a thermodynamic effect whereby energy absorbed at the earth's surface, which is normally able to radiate back into space in the form of long-wave infrared radiation, is retained by gases in the atmosphere, causing a rise in temperature. The gases in question are partially natural, but manmade pollution is thought to increasingly contribute to the effect. The same CFCs that cause ozone depletion are known to be "greenhouse gases," with a single CFC molecule having the same estimated effect as 10,000 carbon dioxide molecules.

Half-life: the time in which the concentration of a chemical in the environment is reduced by half.  

Halons:fire-extinguishing agents with high ODPs.

Hazard Analysis: identification of individual hazards of a system, determination of the mechanisms by which they could give rise to undesired events, and evaluation of the consequences of these events.

Hazard and Operability Study (HAZOP): one of several methods of hazard analysis carried out by application of guide words to engineering and instrument drawings to identify all deviations from design intent with undesirable effects for safety or operability, with the aim of identifying potential hazards.

Hazard Identification: the first step in the risk assessment process. This step includes the identification of a chemical of concern and its potential adverse effects.

Hazard Indicator: a quantitative measurement of a chemical's hazard. Scorecard includes hazard indicators for numerous endpoints, including human health, ecological health, and combined human and ecological health. These are based on different combinations of factors, such as toxicity, persistence, and exposure potential.  

Hazard Ranking: how a chemical's adverse effects compare with other chemicals in a ranking system.  

Hazard: an inherent property of a substance, agent, source of energy or situation having the potential of causing undesirable consequences.

Hazardous Installation: a fixed industrial plant/site at which hazardous substances are produced, processed, handled, stored, used or disposed of in such a form and quantity that there is a risk of a major accident involving hazardous substance(s) which could cause serious harm to human health or damage to the environment, including property.

Hazardous Substance: an element, compound, mixture or preparation which, by virtue of its chemical, physical or (eco)toxicological properties, constitutes a hazard.

HBV: hepatitis B virus

HCFC: Hydrochlorofluorocarbon.

Health effects: indicators having to do with physical conditions or injuries brought about by exposure to stressful working conditions.

Health Hazard: adverse effects to a living organism.  

Healthy carriers: people who have micro-organisms in their body (such as bacteria, viruses, etc.) but do not show any signs of disease and are healthy. However, they may transmit the micro-organism to other people. In the case of HIV/AIDS, this term is inappropriate to describe persons who have the virus but who are in apparently good health, since some (or perhaps all) of these people will later develop the disease and therefore cannot be considered to be perfectly healthy. It is more accurate to use the term "asymptomatic carrier" (literally meaning "without symptoms") for these people. This means that they carry the micro-organism - which they can transmit to others - but do not show any signs of the disease.

Hematopoietic agent: a chemical which interfers with the blood system by decreasing the oxygen-carrying ability of haemoglobin. This can lead to cyanosis and unconsiousness. Carbon monoxide is one such agent, familiar to smokers.

Hepatitis B: a viral infection that damages the liver. Effects can range from inflammation to cirrhosis of the liver, and death.

hepatotoxin: a chemical capable of causing liver damage.

HFC: Hydrofluorocarbon.

High-risk groups: refers to individuals at greatest risk of developing a particular disease. In the case of HIV/AIDS, the high-risk groups are male homosexuals with multiple partners, injecting drug users, haemophiliacs, prostitutes, sexual partners of any of these groups, and children born to seropositive mothers. (See also seropositive.)

HIV (human immunodeficiency virus): the name of the virus that causes AIDS.

HIV-positive: a person who has been tested and is found to be infected with HIV.

Homosexuality: sexual attraction for individuals of the same sex. Homosexuality may be occasional or exclusive.

Hood: a device that encloses, captures, or receives emitted contaminants.

Hormone: a substance, produced by an endocrine gland, that travels through the bloodstream to a specific organ, where it exerts its effect

Host uterus procedure: a woman carries to term a pregnancy produced by an infertile couple through in vitro fertilization

Hostile mucus: cervical mucus that impedes the natural progress of sperm through the cervical canal

Housekeeping: keeping the workplace clean and organized.

Human chorionic gonadotropin(hCG): the hormone produced early in pregnancy to keep the corpus luteum producing progesterone; may be injected to stimulate ovulation and progesterone production

Human Health Ranking: how a chemical's adverse health effects on humans compare with the same effects from other chemicals, in a ranking system.  

HVAC (Heating, Ventilation and Air Conditioning) Systems: ventilating systems designed primarily to control temperature, humidity, odors, and air quality.

Hydrocarbon/surfactant blend: a mixture of low-volatility hydrocarbon solvents with surfactants, allowing the use of a two-phase cleaning process. The first phase is solvent cleaning in the blend and the second phase is water cleaning to remove the residues of the blend and any other water-soluble soils. The surfactant ensures the water-solubility of the otherwise insoluble hydrocarbon. Terpenes are often used in this application.

Hydrocarbon: an organic chemical composed only of hydrogen and carbon. Gaseous or volatile hydrocarbons are flammable.

Hydrochlorocarbon: an organic chemical composed of hydrogen, chlorine and carbon, e.g., trichloroethylene.

Hydrochlorofluorocarbon: an organic chemical composed of hydrogen, chlorine, fluorine, and carbon atoms. These chemicals are less stable than pure CFCs, thereby having generally lower ODPs.

Hydrolysis: a chemical reaction of a substance with water, leading to decomposition or other change of substance.

Hydrophilic: water loving or having a strong affinity for water.

Hydrophobic: water hating or having a strong aversion to water.

Hydrotubation: injection of fluid, often into the fallopian tubes to determine if they are open

Hygiene: the practice of principles that maintain health, e.g. cleanliness.

Hyperandrogenism: excessive production of androgens in women, frequently a cause of hirsutism and also associated with polycystic ovarian disease (PCOD)

Hyperprolactinemia: excessive prolactin in the blood

Hyperstimulation: excessive stimulation of the ovaries that can cause them to become enlarged

Hypothalamus: the endocrine gland at the center of the brain that produces gonadotropin releasing hormone and controls pituitary function

Hypothyroidism: underactivity of the thyroid gland

Hypoxia: a condition defined by a low supply of oxygen.

Hysterectomy: surgical removal of the uterus

Hysterosalpingogram(HSG): an X-ray examination of the uterus and fallopian tubes

Hysteroscopy: examination of the inner cavity of the uterus through a fiberoptic telescope inserted through the vagina and cervical canal

IDLH (Immediately dangerous to life or health): description of an environment that is very hazardous due to a high concentration of toxic chemicals or insufficient oxygen, or both.

ILO Convention: an international labour standard developed through the ILO tripartite system. ILO Conventions are comparable to multilateral international treaties — they are open to ratification by member States and, once ratified, create specific binding obligations. A member State that has ratified a Convention is expected to apply its provisions by legislation or other appropriate means as indicated in the text of the Convention. The government of the member State is required to report regularly on the application of ratified Conventions; the extent of compliance is subject to examination and public comment by ILO machinery; complaints about alleged non-compliance may be made by the governments of other ratifying States or by employers' or workers' organizations. Procedures exist for investigating and acting upon such complaints. Conventions that have not been ratified have the same value as Recommendations (see ILO Recommendation below).

ILO Recommendation: ILO Recommendations are intended to offer guidelines for action by member States. Often, a particular Recommendation will elaborate upon the provisions of a Convention on the same subject. Member States have certain important procedural obligations in respect of Recommendations — namely to submit the texts to their legislative bodies and to report occasionally at the request of the ILO Governing Body on the measures taken or envisaged to give effect to the provisions. Recommendations have no legal obligations.

Immiscible: incapable of mixing or obtaining homogeneity.

Immune system: the body's defense against any injury or invasion by a foreign substance or organism

Immunoglobulins: a class of proteins endowed with antibody activity; antibodies

Immunosuppressive drug: a drug that interferes with the normal immune response

Immunotherapy: a medical treatment for an immune system disorder that involves transfusing donor white blood cells into a woman who has had recurrent miscarriages

Immunotoxicity: adverse effects on the normal functioning of the immune system, caused by exposure to a toxic chemical. Changes in immune function could produce higher rates of infectious diseases or cancer, or more severe cases of those diseases. Immunotoxic chemicals can also cause auto-immune disease or allergic reactions.

Implantation: attachment of the fertilized egg to the uterine lining, usually occurring five to seven days after ovulation

Impotence: inability of a man to achieve an erection or ejaculation

Impulse noise: usually a very loud noise that occurs only once.

In utero: while in the uterus during early development

In vitro fertilization (IVF): (literally, "in glass") fertilization outside of the body in a laboratory; the term "test tube baby" is inaccurate since fertilization occurs in a small circular dish, not a test tube

Incidents: accidents and/or near-misses.

Incompetent cervix: cervix with the inability to remain closed throughout an entire pregnancy; a frequent cause of premature birth

Indicators: the various effects of jobs which are not designed ergonomically. These indicators serve as clues as to which aspect of jobs need to be analyzed and corrected. There are two main categories:

Indirect lightning: lighting which is directed upwards from the operator and the screen. This is sometimes recommended for rooms with VDT's.

Industrial Engineering: industrial Engineering is one of the six major disciplines of engineering (aeronautical, chemical, civil, electrical, and mechanical being the other five). It is the study of, design for, and analysis of productivity, efficiency, cost-effectiveness, optimal decision making, and human-system performance. Subdisciplines include operations research, work measurement, quality control, probability and statistics, human factors engineering, engineering economy, reliability, facility planning, production and inventory control, and manufacturing.

Industrial hygiene: the recognition, measurement and control of workplace hazards.

Industrial Sector: standard Industrial Classification (SIC) codes are a system of numerical codes that categorize industrial facilities by the type of activity in which they are engaged. For example, SIC code 2911 refers to petroleum refineries. Each code number represents an industrial sector.

Industrial ventilation: (IV). the equipment or operation associated with the supply or exhaust of air by natural or mechanical means to control occupational hazards in the industrial setting.

Inert gas soldering: a soldering process done in a relatively oxygen-free atmosphere. The process greatly reduces oxidation of the solder, so that less flux is required, thereby easing or eliminating the need for cleaning.

Infection: an invasion of the body (entry) by a disease-causing organism.

Infertility: inability of a couple to achieve a pregnancy or to carry a pregnancy to term after one year of unprotected intercourse

Inflammation: a response to some type of injury such as infection, characterized by increased blood flow, heat, redness, swelling, and pain

Information: facts or data or other knowledge which can be provided by any means including, for example, electronic, print, audio or visual.

Ingestion: swallowing (such as eating or drinking). Chemicals can get into or onto food, drink, utensils, cigarettes, or hands where they can then be ingested.  

Ingestion: the process of taking a substance into the body through the mouth.

Inhalation: breathing in. Once inhaled, contaminants can be deposited in the lungs, taken into the blood, or both.  

Integrated Health Ranking: how a chemical's adverse human and ecological health effects compare with those of other chemicals, in a relative ranking system.  

Intensity of noise: loudness of noise.

Intermittent noise: noise that is periodic at regular intervals but not continuous.

Intracervical insemination (ICI): artificial insemination of sperm into the cervical canal Intracytoplasmic sperm injection (ICSI) direct injection of a single sperm into an egg

Intratubal insemination (ITI): artificial insemination of sperm, which have been washed free of seminal fluid, into the fallopian tubes

Intrauterine insemination (IUI): artificial insemination of sperm, which have been washed free of seminal fluid, into the uterine cavity

Ion: an atom or group of atoms that is not electrically neutral but instead carries a positive or negative electric charge.

Irritant: a chemical which may cause reversible inflammation on contact.

Isolation: an engineering control in which a hazardous job is moved to a place where fewer people will be exposed, or a worker is moved to a place where he or she will not be exposed at all.

Isopropanol: also known as isopropyl alcohol.

Job design: defines how to carry out a job. It includes the types of tasks that are done, how many and how these tasks should be done, the order in which they are completed and the type of equipment needed to do the work. Job design partially determines the variety of mental, physical activities, and work/rest schedules the worker experiences.

Job stressor: any feature of a job which can have a possible harmful effect on the worker.

Joint: the location where two or more bones meet, and where movement can occur.

Kidney Toxicity: adverse effects on the kidney, urethra or bladder caused by exposure to a toxic chemical. Some such chemicals can cause acute injury to the kidney; others can produce chronic changes that can lead to kidney failure or cancer.

Land-use Planning: consists of various procedures to achieve both general zoning/physical planning as well as case-by-case decisionmaking concerning the siting of an installation or of other developments.

Laparoscopy: examination of the pelvic organs through a small telescope called a laparoscope

Laparotomy: a surgical opening of the abdomen

Latency period: the time period between the exposure and the first signs of disease.

Latent infection: infection from microbes which does not have any clinical signs in the patient. The patient is referred to as a "healthy carrier". However, in the case of HIV infection, it is preferable to use the term "asymptomatic carrier". (See also healthy carriers.)

LC50: (Lethal Concentration 50): is the concentration of a chemical which kills 50% of a sample population. (See also LD50).

LD50: (Lethal Dose 50): is the dose of a chemical which kills 50% of a sample population. In full reporting, the dose, treatment and observation period should be given. Further, LD50, LC50, ED50 and similar figures are strictly only comparable when the age, sex and nutritional state of the animals is specified. Nevertheless, such values are widely reported and used as an effective measure of the potential toxicity of chemicals.

LDLO: Lethal Dose Low.

Leaded surface mount: a surface mount component (SMC) whose external component connection consists of formed leads.

Leadless surface: a surface mount component (SMC) whose external mount component connection consists of metallized terminations that are an integral part of the component body.

Leiomyoma (fibroid): a benign tumor of the uterus

Leukemia: any of several cancers of blood-forming organs (usually bone marrow cells) which cause the uncontrolled production of abnormal white blood cells (leukocytes).  

Leydig cells: the cells in the testicles that make testosterone

LH surge: the sudden release of luteinizing hormone (LH) that causes the follicle to release a mature egg

Ligament: tough fibrous tissue in the body which supports a joint, and prevents unwanted movement.

Liver and Gastrointestinal Toxicity: adverse effects to the structure and/or function of the liver, gall bladder or gastrointestinal tract caused by exposure to a toxic chemical. The liver is frequently subject to chemical-induced injury because of its role as the body's principal site of metabolism. Chemicals that damage the liver can cause diseases such as hepatitis, jaundice, cirrhosis and cancer

Load: an object or weight handled.

Local effect: an effect on the part of the body where a hazardous substance comes into contact with or enters the body.

Local exhaust ventilation: an industrial ventilation system that captures and removes emitted contaminants before dilution into the ambient air of the workplace.

Low-solids flux: a flux that contains little solid matter, thereby easing or eliminating the need for cleaning. See no-clean flux.

Lumbar spine: the lower back region, often referred to as the "small of the back".

Luteal phase defect (LPH): inadequate function of the corpus luteum that may prevent a fertilized egg from implanting in the uterus or may lead to early pregnancy loss

Luteal phase: post-ovulatory phase of a woman's cycle; the corpus luteum produces progesterone, which in turn causes the uterine lining to secrete substances to support the implantation and growth of the early embryo

Luteinized Unruptured Follicle (LUF) syndrome: the failure of a follicle to release the egg even though a corpus luteum has formed

Luteinizing hormone (LH): the pituitary hormone that causes the testicles in men and ovaries in women to manufacture sex hormones

Lyophilic or lypophilic: oil loving. Marked by a strong affinity between a dispersed phase and the liquid in which it is dispersed.

Macroergonomics: macroergonomics is a major subdiscipline of ergonomics or human factors engineering. Where ergonomics focuses on the human element in a human-system combination, macroergonomics takes into consideration the larger environment of the humans in the system. In other words, the human is not an isolated element in systems. Rather the human being is an integrated whole made up of training, experience, education, management, supervision, teamwork, etc. The professional ergonomist is better able to optimize system design when these other interrelated factors are considered as design considerations.

Major Accident: any unplanned, sudden event which causes or is liable to cause serious injury to people or damage to buildings, plant, material or the environment.

Management: employees at, or owners of, a hazardous installation who have the responsibility and authority to take decisions concerning the operation of an installation, including decisions relevant to safety and, where appropriate, employees at a corporate level in the enterprise having such authority.

Manual handling: any activity requiring the use of force exerted by a person to lift, lower, push, pull, carry or otherwise move, hold or restrain a person, animal or thing.

Material safety data sheet: (same as hazard data sheet and chemical safety data sheet) detailed information sheet on chemicals, generally prepared and made available by chemical manufacturers or projects such as the International Programme on Chemical Safety.

MEA: monoethanolamine.

Mechanical Engineering: mechanical Engineering is the study of, design for, and analysis of how mechanical devices work. This form of engineering relies heavily on calculus and physics. Subdisciplines include thermodynamics, mechanics of materials, fluid dynamics, and statics.

Medical surveillance programme: medical programme including pre - employment and periodic examinations which helps to identify early warning signs of occupational diseases.

MEL (Maximum Exposure Limit): is the maximum permitted concentration of a chemical to which a worker may be exposed over an extended period of time. Typically, MELs are quoted in ppm for an 8-hour reference period, though shorter periods may be quoted for some materials. MELs are, in many countries, enforceable by law.

Menarche: the time when a woman has her first menstual period

Menopause: the time when a woman stops having menstrual periods

Menstrual cycle: a fertility cycle lasting on the average 28 days and controlled by secretion of certain hormones in a woman's body. The cycle begins with a two- to five-day period of menstruation (discharge of blood and uterine lining) followed on the 14th day (midpoint) by the release of an egg (ovulation) which travels from one of the ovaries along the fallopian tube to the womb (uterus) where it remains for about a week. If the ovum has not been fertilized by a man's sperm during the few days following ovulation, hormone changes bring about menstruation and a new cycle.

Metal cleaning: general cleaning or degreasing of metallic components or assemblies.

Micro-organisms: germs.

Microsurgery: reconstructive surgery performed under magnification using delicate instruments and precise techniques

Milligrams per cubic metre of air (mg/m3): this is the weight of the substance in a known volume of air. This expression is used for dusts, vapours and gases.

Miscarriage: spontaneous abortion

Miscible: capable of being mixed in any ratio without separation of two phases.

Monitor (or) Monitoring: use of checks, inspections, tours, visits, sampling and measurements, surveys, reviews or audits to measure compliance with relevant laws, regulations, standards, codes, procedures and/or practices; includes activities of public authorities, industry and independent bodies.

Monoethanolamine: a saponifier capable of eliminating rosin fluxes and (MEA) fatty acids.

Morphology: the study of form, such as assessing the shape of sperm during semen analysis

Motility: mothion, such as the forward swimming motion of health sperm

Mucus: secretion from a gland that can be watery, gel-like, stretchy, sticky or dry; fertile mucus is watery and stretchy

Musculoskeletal system: the system of muscles, bones and related structures in the human body which give us form, provide motion and enable us to exert force.

Musculoskeletal Toxicity: adverse effects to the structure and/or function of the muscles, bones and joints caused by exposure to a toxic chemical. Exposures to coal dust and cadmium, for example, have been shown to cause adverse changes to the musculoskeletal system. Examples of musculoskeletal diseases which can be caused by exposure to toxic chemicals include the bone disorders arthritis, fluorosis, and osteomalacia.

Mutagen: an agent that changes the hereditary genetic material which is a part of every living cell. Such a mutation is probably an early step in the sequence of events that ultimately leads to the development of cancer.

Mutagenicity: a change in the genetic material of a living organism, usually in a single gene, which can be passed on to future generations.  

Mutation: an irreversible change in a chromosome or a gene structure in a cell caused by a foreign chemical substance or ionizing radiation. This change usually has a negative effect on cell growth and function. Sex cells (sperm or ova) damaged by a mutagen can transmit undesired traits to offspring for an indefinite number of generations.

Mycoplasm: an infectious agent that falls structurally between a virus and a bacterium

Myomectomy: surgical removal of a uterine fibroid tumor

Near-miss: any unplanned, sudden event which, but for the mitigation effects of safety systems or procedures, could have caused serious injury to people or serious damage to buildings, plant, material or the environment or could have involved a loss of containment possibly giving rise to significant adverse effects.

Nephrotoxicity: same as kidney toxicity.  

Nephrotoxin: a chemical which may cause kidney damage. Common examples include antimony compounds, dimethyl sulphoxide, dimethylformamide and tetrahydrofuran.

Neurotoxicity: adverse effects on the structure or function of the central and/or peripheral nervous system caused by exposure to a toxic chemical. Symptoms of neurotoxicity include muscle weakness, loss of sensation and motor control, tremors, cognitive alterations and autonomic nervous system dysfunction.

Neurotoxin: a chemical whose primary action is on the CNS (Central Nervous System). Many neurotoxins, such as some mercury compounds, are highly toxic, and must only be used unbder carefully-controlled conditions.

No-clean flux: a flux whose residues do not have to be removed from an electronics assembly, therefore no cleaning is necessary. This type of flux is usually characterized by low quantities of residues.

Noncancer Risk Score: how a chemical's non-cancer risk compares with the non-cancer risk from other chemicals, after being converted into a common unit of comparison.

Notification: a requirement to provide specified information related to a hazardous installation in an appropriate manner to competent authorities.

Obstetrician-gynecologist (Ob-gyn): a physician who specializes in the treatment of female disorders and pregnancy

Occupational disease: any disease caused by exposures in the workplace.

Occupational Overuse Syndrome (OOS): injuries arising from overuse of muscles and tendons, most commonly affecting the hands, arms, shoulder and neck. The condition was formerly known as repetitive strain injury (RSI).

Occupational: related to the workplace.

OECD-based Enterprise: enterprise whose corporate headquarters or effective operational control is located in an OECD Member country.

OEL (Occupational Exposure Limit): a (generally legally-enforcable) limit on the amount or concentration of a chemical to which workers may be exposed.

Oligomenorrhea: infrequent and irregular menstrual cycles

Oligospermia: a low sperm count

Operational effects: indicators related to production, quality and performance of work.

Organic acid (OA): see water-soluble flux.

Ova: female reproductive cells present at birth and normally released one at a time monthly by the ovaries; "eggs"; singular, "ovum".

Ovarian cyst: a fluid-containig enlargement of the ovary

Ovarian wedge resection: surgical removal of a portion of a polycystic ovary to produce ovulation

Ovary: the female gonad; produces eggs and female hormones
Ovulation: release of an egg from the ovary

Ozone Depleting Substance: ozone in the stratospheric layer of the Earth's atmosphere keeps 95-99% of the Sun's ultraviolet radiation from striking the Earth. Various chemicals deplete the ozone layer by accelerating processes that destroy ozone, increasing the amount of ultraviolet radiation that reach the surface. This radiation can cause genetic damage, eye damage and damage to marine life.

Ozone depletion potential (ODP): a relative index indicating the extent to which a chemical product may cause ozone depletion. The reference level of 1 is the potential of CFC-11 and CFC-12 to cause ozone depletion. If a product has an ozone depletion potential of 0.5, a given weight of the product in the atmosphere would, in time, deplete half the ozone that the same weight of CFC-11 would deplete. The ozone depletion potentials are calculated with mathematical models that take into account factors such as the stability of the product, the rate of diffusion, the quantity of depleting atoms per molecule, and the effect of ultraviolet light and other radiation on the molecules.

Ozone depletion: accelerated chemical destruction of the stratospheric ozone layer by the presence of substances produced mostly by human activities. The most depleting species for the ozone layer are the chlorine and bromine free radicals generated from relatively stable chlorinated, fluorinated, and brominated products by ultraviolet radiation.

Ozone layer: a layer in the stratosphere, at an altitude of approximately 10 to 50 km, where a relatively strong concentration of ozone shields the earth from excessive ultraviolet radiation.

Ozone: a gas formed when oxygen is ionized by, for example, the action of ultraviolet light or a strong electric field. It has the property of blocking the passage of dangerous wavelengths of ultraviolet light. Although it is a desirable gas in the stratosphere, it is toxic to living organisms at ground level

Pandemic: (disease) prevalent over the whole of a country or over the whole world.

Pap smear: removal of cells from the surface of the cervix to study microscopically

Parts per million (ppm): another expression for the amount of substance in a volume of air or liquid. The concentration of the toxic substance is measured per 1 million parts of air or liquid. (To understand how much 1 ppm is, imagine one drop of blue dye in a pool of a million drops of water.)

PEL: Permissible Exposure Limit.

Pelvic cavity: the area surrounded by the pelvic bone that contains the uterus, fallopian tubes, and ovaries in women, and the prostate gland and seminal vesicles in men

Pelvic imflammatory disease (PID): inflammation of any of the female pelvic organs, usually due to infection from a sexually transmitted disease

Penis: the male organ of sexual intercourse

Pentafluoropropanol: a fluorinated alcohol.

Perchloroethylene: a perhalogenated chlorocarbon solvent used extensively in industrial degreasing and in dry cleaning.

Perhalogenation: an organic molecule is perhalogenated if all the parent hydrogen atoms in a hydrocarbon are replaced with halogen atoms (astatine, bromine, chlorine, fluorine or iodine). For example, carbon tetrachloride (CCl4) is perchlorinated methane (CH4). Chloroform (CHC13) is an example of a simple chlorinated methane, where only three of the hydrogen atoms have been replaced.

Permanent hearing loss: hearing loss that cannot be repaired.

Permissible exposure limit (PEL): an eight-hour time-weighted average (TWA) concentration of a contaminant that must not be exceeded; PELs are established so that "nearly all" workers are safe if the exposure is not greater than the PEL. This means that some workers might suffer health damage;  many PELs are designed to prevent acute health effects but do not adequately take into account chronic effects. PELs are required by law in some countries. PELs can be expressed in two different ways:

Peroxidizable materials: can form peroxides in storage, generally when in contact with the air. These peroxides present their most serious risk when the peroxide-contaminated material is heated or distilled, but they may also be sensitive to mechanical shock. The quantity of peroxides in a sample may be determined using a simple peroxide test strip.

Persistent Organic Pollutants (POPs): persistent Organic Pollutants (POPs) are chemicals, chiefly compounds of carbon, that persist in the environment, bioaccumulate through the food chain, and pose a risk of causing adverse effects to human health and the environment.

Personal hygiene: the practice of principles that maintain personal health, e.g. personal cleanliness.

Personal protective equipment: equipment a worker wears as a barrier between himself or herself and the hazardous agent(s).

Photoallergic contact dermatitis: is a skin condition brought on by exposure to light following skin contact with certain types of chemicals, such as sulphonamides.

Photochemical reaction: a chemical reaction caused by light or ultraviolet radiation.

Photoresist: a photomechanical product, in the form of a liquid or a laminated dry film, used in the manufacture of printed circuits. Certain types require the use of large quantities of ozone-depleting hydrochlorocarbon solvents, mostly 1,1,1-trichloroethane and methylene chloride, for their processing.

Photosensitization: sensitization or heightened reactivity of the skin to sunlight, usually due to the action of certain drugs.  

Pickling: the removal of oxides (rust) with acidic materials.

Pituitary gland: the endocrine gland at the base of the brain that produces the gonadotropin luteinizing hormone and follicle stimulating hormone, which in turn stimulate the gonads to produce sex cells and hormones

Pollution Prevention: an approach that avoids creating toxic chemical emissions and waste in the first place; it reduces the amount of toxic chemicals that businesses need to use in their operations.

Polycystic ovarian disease (PCOD): a condition found among women who do not ovulate, characterized by multiple ovarian cysts and increased androgen production

Polymers: compounds of very high molecular weights that are made up of a large number of simple molecules which have reacted with one another.

Polyp: a growth or tumor on an internal surface, usually benign

Post-coital test (PCT): microscopic examination of a woman's cervical mucus at the fertile time of the cycle to determine the number and motility of sperm following intercourse

Postnatal: occurring sometime after birth, with reference to the newborn infant.  

Posture: maintenance of the three spinal curves in the cervical, thoracic and lumbar regions.

Potential hazard: something that may be hazardous.

POTW: publicly owned treatment works, local water/sewage treatment facility.

PPM: parts per million.

Precision cleaning: cleaning of high-precision mechanical parts and electronic sensory devices, as opposed to general metal cleaning. This is usually done under controlled atmospheres, notably in clean-rooms with low particle contamination.

Pre-embryo: a fertilized egg in the early stage of development prior to cell division

Prenatal: preceding birth, with reference to the fetus.  

Preservative: see condom.

Printed circuit: a printed circuit is an electronic component designed for interconnecting the other components. It usually consists of a metallic conductor pattern on an organic insulating substrate. After fabrication, it is known as a printed circuit board (PCB); after assembly where components are added, it is known as a printed wiring assembly (PWA).

Probability: the likelihood that a considered occurrence will take place.

Product Stewardship: a system of managing products through all stages of their life cycle including customer use and disposal (with the objective of continuously improving safety for health and the environment).

Progesterone: the female hormone, produced by the corpus luteum after ovulation, that prepares the uterine lining for implantation of a fertilized egg and helps maintain the pregnancy

Prolactin: the pituitary hormone that in high amounts stimulates milk production

Prolonged: the excessive length of time spent doing an action, or holding a posture.

Prostaglandins: a group of hormone-like chemicals that have various effects on reproductive organs; so named because they were first discovered in the prostate gland.

Prostate gland: the male gland encircling the urethra that produces one third of the fluid in the ejaculate

Public Authorities: government bodies at national, regional, local and international level with the authority to issue licenses, regulations, standards or other instructions having the force of law.

Pyrophoric materials: ignite spontaneously in air. Since a wide variety of chemicals will burn if heated sufficiently, it is usual to define a pyrophoric material as one which will ignite spontaneously at temperatures below about 45 C.

Reasonably Practicable: all which is possible subject to the qualification that the costs of the measures involved are not grossly disproportionate to the value of the benefits obtained from these measures.

Recognized Human Health Hazard: authoritative national and international scientific and regulatory agencies have identified some chemicals that cause specific adverse health effects with enough certainty to consider the effect a recognized hazard of the chemical. To date, such efforts have been focused on cancer, reproductive toxicity, and developmental toxicity.

Reference Concentration (RfC): an estimate of the daily inhalation dose, expressed in terms of an ambient concentration, that can be taken daily over a lifetime without appreciable risk

Reference Dose (RfD): an estimate of the daily ingestion dose, expressed in terms of amount per unit of body weight, that can be taken daily over a lifetime without appreciable risk

Reflow soldering: a method of electronics soldering commonly used with surface mount technology, whereby a paste formed of solder powder and flux suspended in an organic vehicle is melted by the application of external heat.

Repetitive strain injury: another term for Cumulative Trauma Disorder.

Replacement air: (also, Compensating Air, Make-Up Air). Air supplied to a space to replace exhausted air.

Reproductive endocrinologist: an ob-gyn who specializes in the treatment of hormonal disorders that affect reproductive function

Reproductive surgeon: an ob-gyn or urologist who specializes in the surgical correction of anatomical disorders that impair reproductive function

Reproductive Toxicity: adverse effects on the male and/or female reproductive systems caused by exposure to a toxic chemical. Reproductive toxicity may be expressed as alterations in sexual behavior, decreases in fertility or fetal loss during pregnancy. Some official definitions of reproductive toxicity, for example in California's Proposition 65, include developmental toxicity as part of reproductive toxicity.

Reproductive toxin: a chemical which may cause birth defects or sterility.

Residual risk: the risk still remaining after the implementation of risk management practices.

Respiratory hazards: hazards to the body's breathing system.

Respiratory toxicity: adverse effects on the structure or function of the respiratory system caused by exposure to a toxic chemical. Respiratory toxicants can produce a variety of acute and chronic pulmonary conditions, including local irritation, bronchitis, pulmonary edema, emphysema and cancer.

Retrograde ejaculation: ejaculation backwards into the bladder instead of forward through the urethra.

Return air: air that is returned from the primary space to the fan for recirculation.

Risk assessment value: risk assessment values are numbers that help define the level of health risk, both cancer and noncancer, posed by a toxic chemical. They are derived from dose-response assessments of animal or human studies that indicate a chemical can cause an adverse health effect

Risk assessment: an organized process used to describe and estimate the amount of risk of adverse human health effects from exposure to a toxic chemical (how likely or unlikely it is that the adverse effect will occur). How reliable and accurate this process is depends on the quantity and quality of the information that goes into the process. The four steps in a risk assessment of a toxic chemical are hazard identification, dose-response assessment, exposure assessment, and risk characterization.

Risk characterization: an organized process used to evaluate, summarize, and communicate information about the likelihood of adverse health or ecological effects from particular exposures to a toxic chemical in the environment, i.e. how individuals or populations may be affected. It includes discussion of the kind of evidence it uses and how strong that evidence is. Risk characterization is the final step in the process of risk assessment.

Risk management: actions taken to achieve or improve the safety of an installation and its operation.

Risk: the probability that damage to life, health, and/or the environment will occur as a result of a given hazard (such as exposure to a toxic chemical). Some risks can be measured or estimated in numerical terms (e.g., one chance in a hundred).  

Rosin flux: a flux whose main constituent is rosin. There are several categories of rosin flux, often designated by the codes R (pure rosin), RMA (rosin, mild activation), RA (rosin, activated usually with free chloride ions), RSA (rosin, super activated), SA (synthetic resin, activated).

Rosin: a solid resin obtained from pine trees which, in a pure form and usually with additives, is frequently used as a flux.

Route of exposure: the avenue by which a chemical comes into contact with an organism (such as a person). Possible routes include inhalation, ingestion, and dermal contact.  

Routes of entry: the different ways hazardous agents can get into the body.

Safe levels: levels of exposure to substances below which there will not be a health risk to workers.

Safety assessment: the process of evaluating the safety (or lack of safety) of a chemical in the environment based upon its toxicity and current levels of human exposure.

Safety audit: a methodical in-depth examination of all or part of a total operating system with relevance to safety.

Safety report: the written presentation of the technical, management and operational information concerning the hazards of a hazardous installation and their control in support of a justification for the safety of the installation.

Safety: a situation without unacceptable risks. For purposes of this text, "safety" embraces health, safety and environmental protection, including protection of property.

Salpingectomy: surgical removal of the fallopian tubes

Salpingitis isthmica nodosa: an abnormal condition of the fallopian tube where it attaches to the uterus, characterized by nodules

Salpingitis: inflamation of one or both fallopian tubes

Salpingostomy: an incision in a fallopian tube, such as to remove an ectopic pregnancy

Salpingotomy: an operation to open a blocked fallopian

Saponification: the breaking down of oils into very fine droplets called colloids; to hydrolyze a fat with alkali to form a soap and glycerol.

Saponifier: a chemical designed to react with organic fatty acids, such as rosin, some oils and greases, to form a water-soluble soap. This is a solvent-free method of defluxing and degreasing many parts. Saponifiers are usually alkaline and may be mineral (based on sodium hydroxide or potassium hydroxide) or organic (based on water solutions of monoethanolamine).

scfm: standard cubic feet per minute. A measure of air flow at standard conditions, i.e., dry air at 29.92 in Hg (760 mm Hg) (gauge), 68 degrees F (20 degrees C).

Screening level : screening level information about a chemical's toxicity or exposure potential is derived from readily available information using methods that do not require extensive analyses to support preliminary evaluations of chemical safety. Screening level information is useful and necessary for ranking potential problems, directing more detailed investigations, and taking preventative action.  

Screening risk assessment: a risk assessment performed using available data and many assumptions to identify toxic chemical releases that have a higher probability of posing health risks. If potential health risks are identified, further investigation or risk reducing actions may be warranted.

Scrotum: the sac containing the testicles, epididymis, and vas deferens

Semen analysis: laboratory examination of semen to check the quality and quantity of sperm

Semen: fluid produced by the seminal vesicles and the prostate gland in men which contains the sperm. In infected males, semen also contains cells infected with HIV and is therefore able to transmit the infection to sexual partners.

Seminal vesicles: the paired glands at the base of the baldder that produce seminal fluid and fructose

Seminiferous tubules: in the testicles, the network of tubes where sperm are formed

Sensitizer: is a chemical which may lead to the development of allergic reactions after repeated exposure.

Septum: a wall that divides a cavity in half, such as a uterine septum

Seroconversion: the appearance of antibodies in the serum (the liquid part of the blood) so that a person who was previously antibody-negative becomes antibody-positive. With HIV, seroconversion (the appearance of antibodies to HIV) usually occurs 4 to 12 weeks after a person becomes infected.

Serological test for HIV: blood test that allows the presence of antibodies to HIV in the body to be detected.

Seropositive: in the case of HIV/AIDS, a person with a positive screening test for antibodies directed against HIV. This person has been in contact with the virus and should be considered as capable of transmitting the virus to others. When the test does not detect antibodies, the person is said to be "seronegative".

Sertoli cells: the cells in the testicles that provide nourshment to the early sperm cells

Sexually transmitted disease (STD): a disease caused by an infectious agent transmitted during sex

Short-term exposure limit (STEL): the maximum concentration that must not be exceeded for a continuous 15-minute exposure period. STELS are required by law in some countries.

SIDS: the Screening Information Data Set created by the member countries of the Organization for Economic Cooperation and Development (OECD) in 1990, for purposes of screening high-production-volume chemicals used in those countries. The purpose of the SIDS program is to complete initial screening tests on those chemicals to identify their potential hazards to human health and the environment, so that risk assessments can then be done for the chemicals with sufficient hazard potential. The data set is a list of the tests and other information about a chemical that OECD considers to be the necessary minimum for purposes of this preliminary screening.  

Skin and Sense Organ Toxicity: adverse effects on the skin or sensory organs caused by exposure to a toxic chemical. Sense organs include eyes, ears, etc.

SMC: surface mount component.

SMD: surface mount device.

Solvent containment: means of preventing or reducing the emission of CFC or other solvents into the environment. This technique usually involves improving the design of the equipment in which the solvent is used and preventing losses.

Solvent: a product (aqueous or organic) designed to clean a component or assembly by dissolving the contaminants present on its surface.

Sperm bank: a place where sperm are kept frozen in lizuid nitrogen for later use in artificial insemination

Sperm count: the number of sperm in the ejaculate (when given as the number of sperm per millileter it is more accurately known as the sperm concentration or sperm density)

Sperm: male gamete or reproductive cell

Spermicide: an agent that kills sperm

Sprain or Strain: trauma to a joint, ligament or muscle which causes pain.

Stack: a device on the end of a ventilation system that disperses exhaust contaminants for dilution by the atmosphere.

Static: referring to muscle action, without movement of a part of the body. The opposite to dynamic. Muscles which work statically fatigue rapidly.

STD: abbreviation for sexually transmitted disease. STDs are diseases that can be contracted by means of sexual relations. AIDS is essentially a sexually transmitted disease.

STEL (Short Term Exposure Limit): the maximum permissible concentration of a material, generally expressed in ppm in air, for a defined short period of time (typically 5 minutes). These values, which may differ from country to country, are often backed up by regulation and therefore may be legally enforceable.

Sterilization reversal: a surgical procedure used to undo a previous sterilization operation and restore fertility

Sterilization: a surgical procedure (such as tubal ligation or vasedtomy) designed to produce infertility

Storage Facilities: warehouses, tank farms and other facilities where hazardous substances are held.

Subsidiaries: enterprises in which another enterprise has majority voting rights and/or effective operational control.

Substitution: replacing particularly hazardous chemicals or work processes by safer ones.

Superovulation: stimulation of multiple ovulation with fertility drugs; also known as controlled ovarian hyperstimulation (COH)

Surface mount component (device): a component (device) capable of being attached to a PCB by surface mount technology. The device may be either leaded or leadless.

Surface mount technology (SMT): a technique of assembling SMDs or SMCs on the surface of PCBs and PWAs, as opposed to wiring them through holes. Surface mount technology offers a number of important advantages, but also some disadvantages, such as difficulty in defluxing under certain types of SMD.

Surfactant: a product designed to reduce the surface tension of water. Also referred to as tensio-active agents/tensides. Detergents are made up principally from surfactants.

Surrogate mother: a woman who becomes artificially inseminated with a man's sperm and carries the pregnancy for an infertile couple, who adopt the baby after its birth (the man being the biological father of the child)

Susceptible: open to hazards, germs, etc.

Suspected human health hazard: these are hazards to human health from a chemical that are indicated by some scientific evidence, but that have not been conclusively determined by an authoritative scientific or regulatory organization. Scorecard uses numerous reports in the scientific or regulatory literature, and information abstracted from major toxicological databases, as its sources for identifying chemicals with suspected human health hazards of different kinds. Inclusion of a chemical on a "suspected" list should be viewed as a preliminary indication that the chemical may cause this effect, rather than a definitive finding that it does.

Symptomatic HIV infection: this condition has commonly been referred to as AIDS-related complex (ARC). Signs and symptoms that HIV-infected persons may exhibit during the symptomatic stage of infection include generalized lymphadenopathy (swollen lymph glands), oral lesions and non-specific health complaints such as persistent diarrhoea. The symptoms are not as severe as those that define AIDS. (It is more accurate to describe a patient's condition with a description of symptoms, which may cover a wide range of conditions, and laboratory evidence of HIV infection rather than using the term "ARC".)

Synergism (chemical): when the adverse effect or risk from two or more chemicals interacting with each other is greater than what it would be if each chemical was acting separately.  

Systemic effect: an effect that occurs anywhere in the body once an agent hazardous to health has entered.

Target organs: those parts of the body that particular chemicals always affect. For example, lead affects the central nervous system (brain and spinal cord) but is stored in the bones where it accumulates with further exposures. Therefore, the target organs for lead are both the central nervous system and the bones. Other target organs for different toxic substances include the heart, lungs, kidneys and liver.

Temporary hearing loss: short-term hearing loss, usually characterized by ringing in the ears and a feeling of deafness.

Temporary threshold shift: an effect producing temporary hearing loss that can result from short-term noise exposure.

Tendinitis (or TENDONITIS): a form of tendon inflammation when a muscle/tendon unit is repeatedly tensed. With further exertion, some fibers of the tendon can fray or tear apart. The tendon becomes thick, bumpy and irregular. Without time to rest and time to heal, the tendon may be permanently weakened.

Tennis elbow (or LATERAL EPICONDYLITIS): when strained or subjected to overuse, the tendons become irritated and radiate pain from the elbow down to the forearm.

Tenosynovitis: a condition in which the tendon sheath becomes inflamed (excessive synovial fluid is produced) from either excessive pull, excessive back and forth motions, or a direct blow to the tendon. When it occurs in the tendons of the wrist, tenosynovitis may cause another condition called Carpal Tunnel Syndrome.

Teratogen: a chemical which may cause genetic mutations or malformations in the developing foetus.

Terpenes: any of many homocyclic hydrocarbons with the empirical formula C10H16 and a characteristic odor. Turpentine is mainly a mixture of terpenes. Other common terpenes are pinene and limonene

Testicle: the male gonad; produces sperm and male sex hormones

Testicular biopsy: the removal of a fragment of a testicle for examination under the microscope

Testosterone: the primary male sex hormone

Thoracic outlet syndronme: a condition caused by the pinching or squeezing of the nerves and blood vessels between the neck and shoulder. It can cause shoulder and/or wrist pain. This can happen when work tasks require repeated reaching above the shoulder.

Thoracic spine: the area of the spine where the ribs are located.

Threshold limit value (TLV): an eight-hour time-weighted average (TWA) concentration of a contaminant that should not be exceeded in an eight-hour work shift (i.e. the maximum amount of a substance someone can be safely exposed to over an eight-hour day); usually issued by private industrial hygiene research organizations; based on toxicity, type of health effect, human health data, industrial use data and technological feasibility (whether it is possible to work at that level with the existing technology); intended to protect nearly all healthy or average workers for a lifetime exposure; recent studies suggest that many TLVs are set too high to protect workers' health, therefore it is best to keep the concentration of pollutants as far below the TLVs as possible; updated every two years;  TLVs are only recommended limits. TLVs can be expressed in two different ways:

1. Milligrams per cubic metre of air (mg/m3): This is the weight of the substance in a known volume of air. This expression is used for dusts, vapours and gases.

2. Parts per million (ppm): Another expression for the amount of a substance in a volume of air. The concentration of the toxic substance is measured per 1 million parts of air. (To understand how much 1 ppm is, imagine one drop of blue dye in a pool of a million drops of water.)

Substances with high TLVs, such as freon, are not very toxic. Substances with low TLVs, such as ozone, are very dangerous in even small amounts.

Threshold: a level of chemical exposure below which there is no adverse effect and above which there is a significant toxicological effect.  

Thyroid gland: the endocrine gland in the front of the neck that produces thyroid hormones, which regulate the body's metabolism

Time-weighted average (TWA): exposure levels for an eight-hour work shift are calculated using time-weighted averages. Using the TWA system, if an employer exposes workers to levels below the PEL for part of the day, it is legal to expose those workers to levels above the PELs for the remainder of the day provided the time-weighted average is below the limit.

TLV (Threshold Limit Value): the maximum permissible concentration of a material, generally expressed in parts per million in air for some defined period of time (often 8 hours). These values, which may differ from country to country, are often backed up by regulation and therefore may be legally enforceable.

Tocolytic: a drug that relaxes smooth muscles and therefore interferes with uterine contractions; frequently used to stop premature labor

Torque: the tendency of a force to produce rotation around an axis.

Total effective sperm count: an estimate of the number of sperm in an ejaculate capable of fertilization; total sperm count X percent motility X percent forward progressive motility X percent normal morphology

Total hazard value: a quantitative value representing the total hazard of a chemical substance, derived by integrating the chemical's human health effects, ecological effects, and exposure potential.  

Toxic equivalency potentials: how a chemical's adverse human health effects compare with those of other chemicals, after being converted into a common unit of comparison (Scorecard uses benzene-equivalents for carcinogens and toluene-equivalents for non-carcinogens).

Toxic substance: a poisonous substance that can destroy life or injure health.

Toxicity weight: how a chemical's toxicity - either chronic, acute, or both - compares with other chemicals in a relative ranking system.

Toxicity: the extent, quality, or degree of being poisonous or harmful to humans or other living organisms.  

Toxin: a poison produced by a living organism, such as by some bacteria

Transfer of technology: the movement of process and other safety-related technology from one country to another, embracing not only the actual transfer but also the application of the technology as well as the operation of the plant.

Transfrontier damage: any serious damage to human health or the environment, including property, in the event of an accident suffered by a country other than the country where the accident originated.

Trigger finger (or STENOSING TENOSYNOVITIS CREPITANS): when the tendon sheath of a finger is swollen so that the tendon becomes locked in the sheath, and attempts to move that finger causes a snapping and jerking movement. The palm side of the fingers is the usual sight for trigger finger. This disorder is often associated with using tools that have handles with hard or sharp edges.

Tubal ligation: surgical sterilization of a woman by obstructing or "tying" the fallopian tubes

Tuboplasty: plastic or reconstructive surgery on the fallopian tubes to correct abnormalities that cause infertility

Tumor: an abnormal growth of tissue that can be benign or malignant (cancerous)

TWA (Time Weighted Average): this term is used in the specification of Occupational Exposure Limits (OELs) to define the average concentration of a chemical to which it is permissible to expose a worker over a period of time, typically 8 hours.

Ultrasound (US): use of high-frequency sound waves for creating an image of internal body parts

Upper extremeties: the hands, arms and shoulders of the human body.

Ureaplasma: a microorganism similar to mycoplasma

Urethra: the tube through which urine from the bladder is expelled

Urologist: a physician who specializes in the surgical treatment of disorders of the uniary tract and male reproductive tract

Uterus: the womb; female reproductive organ that noursishes the fetus until birth

Vagina: the female organ of sexual intercourse; the birth canal

Vaginituis: inflammation of the vigina

Vapor phase cleaning: a cleaning process, usually with CFC-113 solvent or hydrochlorocarbon solvents, in which the final rinse of the parts being cleaned is achieved by condensing solvent vapors on the parts.

Vapor pressure: total gas pressure at equilibrium due to a specific compound present as liquid and gas. For example, the pressure due to the evaporation of a solvent when as much has evaporated as the air can hold under current conditions.

Vapour density: the relative density or weight of a vapour or gas compared with an equal volume of air. If the vapour density of a substance is less than one, it will tend to rise in air; if the vapour density is greater than one, it will fall in air. Substances with high vapour densities will collect in the bottom of tanks.

Vapour pressure: a high vapour pressure indicates that a liquid will evaporate easily. Materials with high vapour pressures can be especially hazardous when they are being used in an enclosed area or in an area with poor circulation.

Vapour: tiny droplets of liquid suspended in the air.

Varicocele: varicose veins in the scrotum

Vas deferens: the tubes that conduct sperm and testicular fluid to the ejaculatory ducts

Vasectomy reversal: surgical repair of a previous vasectomy for a man who wants to regain his fertility

Vasectomy: surgical sterilization of a man by interrupting both vas deferens

Vasogram: an X-ray study of the vas deferens

Velocity (V):. the time rate of movement of air; usually expressed as feet per minute.

Venereal disease: see sexually transmitted deseases (STD)

Vertebrae: the small bones making up the spine.

Vibration white fingers (or REYNAUD'S SYNDROME): condition caused by damage from vibration on the blood vessels. The fingers whiten and become numb. This condition, like Carpal Tunnel Syndrome, can be mild or quite severe and disabling.

Virus: a microscipic infectious organism that reproduces inside living cells

VOCs: Volatile Organic Compounds.

Volatile organic compound (VOC): the environmental or legislated definition: Constituents that will evaporate at their temperature of use and which, by a photochemical reaction, will cause atmospheric oxygen to be converted into potential smog-promoting tropospheric ozone under favorable climatic conditions. Some areas classify a substance to be a VOC based on its vapor pressure. Scientific definition: Any hydrocarbon, except methane and ethane, with a vapor pressure equal to or greater than 0.1 mm Hg.

Volatile: a term often used to describe a liquid that evaporates or vaporizes easily. This is important to know because air concentrations can build up quickly when the material is used in its liquid form.

Warehousekeeper: the person responsible for a storage facility, whether on the site of a hazardous installation or off-site.

Water-soluble flux: a flux, which itself may be free from water, but whose residues after soldering may be entirely eliminated by a water wash. Such fluxes are usually very active so adequate defluxing is an essential part of their use. They are also known as organic acid (OA) fluxes or inorganic acid fluxes.

Wave soldering: also known as flow soldering, a method of mass soldering electronics assemblies by passing them, after fluxing, through a wave of molten solder.

Weight of evidence: the evaluation of published information about a chemical's toxicity and exposure potential that leads to a conclusion about that chemical's safety or hazard. Important factors include the adequacy and number of available studies; the consistency of results across studies; and the biological plausibility of dose-response relationships.  

Wet-method: spraying water over a dusty surface to keep dust down, or mixing water with the material used to prevent dust from being created.

Wetting agents: another name for surfactants.

Wetting: the action by which a cleaner penetrates and loosens the substrate-soil bond by lowering surface and interfacial tension.

Work environment: physical conditions such as lighting, temperature, humidity, space and noise level. It can also include social relations and psychological factors at work.

Work Measurement: work measurement is the study and analysis of the human element in work situations and is a major subdiscipline of Industrial Engineering. The professional industrial engineer can conduct time studies, perform work sampling exercises, and execute line balancing calculations. The fundamental purpose of work measurement is to determine the most optimal performance and output that is feasible and possible from a particular work configuration involving facilities, equipment, materials, and human beings.

Work Sampling: a key technique of industrial engineering, work sampling is a method of analyzing systems and operations using statistically valid sampling or random selections or observations. This technique is a tremendous time saver and enables meaningful analyses to be performed simply, quickly, and at low cost.

Workstation: the workspace occupied by a specific worker. It includes all fixtures such as fixed machines and equipment, the worktable or bench, stools, chairs, and any supply and output containers or conveyors.

Zeolite: a natural or synthetic hydrated aluminosilicate with an open three-dimensional crystal structure in which water molecules are held; often called molecular sieves.

Zona pellucida: the protective coating surrounding the egg

Zygote Intra Fallopian transfer (ZIFT): in vitro fertilization with a transfer of the zygote into the fallopian tube; a combination of in vitro fertilization and gamete intrafallopian transfer

Zygote: an egg that has been fertilized but not yet divided