Glossary

Absorption

A process by which a substance may be incorporated or taken into the body (e.g. through the skin). Penetration of a substance into another substance.

Accumulate:

Increase, build up.

ACGIH:

Abbreviation for American Conference of Governmental Industrial Hygienists.

Acid:

A chemical which has the ability to neutralise an alkali to form a salt. Certain acids react vigorously with metals, releasing hydrogen gas. Acids may also be corrosive to the skin, eyes and mucous membranes, especially in concentrated form. Acid turns blue litmus paper red. Sulphuric, hydrochloric and nitric acid are common examples.

Acidosis:

Acid poisoning in the blood.

Acute effect:

An adverse effect on a human or animal, following a single dose or short exposure with symptoms developing rapidly.

Acute toxicity:

The toxic effects resulting from a single dose or short exposure to a substance.

ADN/ADNR:

ADN - Accord relatif au transport de marchandises Dangereuses par voies de Navigation intérieures (European Provisions concerning the International Carriage of Dangerous Goods by Inland Waterways). ADNR - Accord relatif au transport de marchandises Dangereuses par voies de Navigation intérieures sur le Rhin (Provision concerning the Carriage of Dangerous Goods on the Rhine).

ADR:

An Agreement drawn up by the United Nations Economic Commission for Europe in Geneva, whereby most States in Europe have agreed common rules for the movement of dangerous goods by road across their frontiers and through their territories. The abbreviated name "ADR" comes from key words in the French title Accord européen relatif au transport international des marchandises Dangereuses par Route (European Agreement concerning the international carriage of dangerous goods by road).

Administrative controls:

Controls designed to limit the amount of time a worker spends at a potentially hazardous job.

Adsorption:

Condensation of gases, liquids or dissolved substances on the surfaces of solids.

Adverse effect (response:

Any change from an organism’s normal state. Producing a toxic adverse effect depends on the concentration of the active compound at the target site. Some of these changes may be short-lived, functional and relatively reversible at low dosages and become chronic and irreversible at higher dosages.

Aerobes:

Micro-organisms that survive in the presence of oxygen (air).

Aerosol:

An airborne mist of a solid or liquid substance.

Air monitoring:

Air monitoring means monitoring of the concentrations of airborne hazardous chemical substances. The sampling and measuring of pollutants in the air.

Alcohol resistant foam:

Medium to fight fires of highly flammable, water soluble substances. It has less mechanical strength than other foams.

Aliphatics:

Refers to an open-chain or fatty series of hydrocarbons. Usually applied to petroleum products derived from a paraffin or olefin base and having a straight or branched chain molecular structure. Substances such as ethane and ethylene are typical aliphatic hydrocarbons. Also see "Aromatic".

Alkali:

A compound that has the ability to neutralize an acid to form a salt. A substance which is somewhat irritating or corrosive to the skin, eyes and mucous membranes. Turns red litmus paper to blue. Common strong alkalis are sodium and potassium hydroxide.

Allergic reaction:

An abnormal physiological response in a person who has become hypersensitive to a specific substance. Some forms of dermatitis and asthma may be caused by allergic reactions to chemicals.

Anaerobe:

Micro-organisms that survive without oxygen (air).

Anaesthetic effect:

The temporary loss of feeling which reduces the ability to feel pain and/or other sensations.

Antidote:

An agent that neutralizes or counteracts the effects of a poison.

Approved inspection authority:

Defined in the Occupational Safety Act: An inspection authority approved by the chief inspector: Provided that an inspection authority approved by the chief inspector with respect to any particular service shall be an approved inspection authority with respect to that service only.

Aromatic:

The name "aromatics" is derived from their rather pleasant odour. The chemical may, however, be carcinogenic. Refers to petroleum products which have a ring molecular structure. Aromatics tend to burn with black, smoky flames. Benzene, toluene and xylene are the principal aromatics.

Asphyxiant:

A vapour or gas which can cause unconsciousness or death by suffocation (lack of oxygen).

Aspiration hazard:

The danger of drawing a fluid into the lungs and causing chemical pneumonia or other inflammatory response.

Association:

The relationship between two or more events, characteristics, or other variables, often quantified in statistical terms. Synonyms are correlation, statistical dependence and relationship. A (numerical) relationship between 2 or more events, characteristics, or other variables.

ASTM:

American Society for Testing Materials.

Attenuation:

Attenuation means the proven capability of hearing protectors to reduce the equivalent noise level to which the wearer thereof is exposed.

Auto-ignition temperature:

The approximate lowest temperature at which a flammable gas or vapour-air mixture will spontaneously ignite without spark or flame.

Bar:

A non SI unit of pressure. Normal atmospheric pressure = 1.013 bar (= 1013 mbar).

BEI:

Abbreviation for Biological Exposure Index. The Biological Exposure Index (BEI) is a reference value intended as a guideline for the evaluation of potential health hazards.

Bias:

A systematic deviation from the truth. Any trend in the collection, analysis, interpretation, publication, or review of data that can lead to conclusions that are systematically different from the truth. We understand bias as either selection or information bias. See confounding.
Selection bias. This occurs where there are systematic differences in characteristics between those in the population selected for study and those that are not.
Information bias. This occurs where there are systematic errors in measurement, recording, management, analysis or reporting of data. Most often, information bias is an error due to different quality or accuracy of information between groups compared. It refers to measurement of exposure or of effect.

Bioaccumulation:

The process in and by which chemical substances are accumulated in living organisms.

Bioavailability:

The medium a substance is found in, its physical and chemical properties, shape, size, reactivity and solubility, determine how readily it enters the body, how it distributes within the body, and the rate of its excretion. The activity of toxicity of a given substance may be dramatically decreased by the chemical species, protein binding or environmental matrix.

Biodegradation:

Natural decomposition of a substance via biological processes.

Biological monitoring:

Usually consists of blood and urine tests performed to look for traces of chemicals and biological indicators of chemical exposure.

Biolmarkers

Biomarkers fall into three principal categories: exposure, susceptibility and effect. Exposure assessments have traditionally depended almost exclusively on measurements or model predictions of concentrations of chemical pollutants in relevant environmental media such as air, water, food and soil. An example of a biomarker of exposure is a measurement of a substance or its metabolite and provides an indication of degree of exposure. A biomarker of effect is a measurable biochemical, physiologic or other alteration within an organism that, depending on magnitude can indicate potential or established disease (DNA adducts, specific enzyme activity etc.). A biomarker of susceptibility is an indicator of an inherent or acquired variation in an organism's ability to tolerate a specific substance. Susceptibility may vary due to combinations of environmental characteristics, genetic predisposition, age, gender, diet, lifestyle factors, comorbidity and other factors. Optimally a biomarker should be an indicator of both dose and effect.

Body burden:

A concept related to bioavailability reflecting the total amount of a substance within the body at a point in time and depends upon total dosage, metabolism and elimination or excretion.

Boiling point:

The temperature at which a liquid changes to a vapour state, at a given pressure. For mixtures, the initial "boiling point" or the "boiling range" may be given.

Burns:

An injury to skin tissue caused by heat, chemicals, electricity or irradiation.

Carcinogen:

A substance or agent capable of causing cancer.

CAS number:

A number assigned to specific chemicals by the Chemical Abstracts Service. (An organization operated by the American Chemical Society which indexes chemical information). The CAS number is a concise, unique means of chemical identification.

Caustic:

A compound that strongly irritates, burns, corrodes or destroys living tissue.

cc:

An abbreviation for "cubic centimeter" (cm³. 1 cc = 1 ml (millilitre).

ºC:

Degrees Celsius or Centigrade.

Chemical pneumonitis:

Inflammation of the lungs, caused by inhalation or aspiration of an irritating substance.

Chronic effect:

An effect that usually appears a long time after the exposure occurred and persists over time.

CL:

The maximum allowable human exposure limit for an airborne substance; not to be exceeded, even momentarily. Also see "PEL" and "TLV.

COC:

Material which potentiates the effect of a carcinogen.

Cocarcinogen:

Cleveland Open Cup: a flash point test method.

Coma:

A state of deep unconsciousness from which one cannot be aroused, even by powerful stimulation.

Combustible:

A substance capable of fuelling a fire.

Compatibility:

Ability of two or more substances to mix without objectionable changes in their physical or chemical properties.

Condensation:

Change in physical state of a substance from vapour to liquid (or solid) form.

Confounding:

This occurs where the effects of two concurrent or simultaneous processes in causing an outcome are not explicitly separated. (Risk factor 1 seemingly causes an outcome, but in reality another risk factor 2 is mixed-in with risk factor 1 and distorts the apparent contribution of risk factor 1, by having an impact on the outcome.) See bias.

Container:

Any bag, barrel, bottle, box, can, drum, reaction vessel, storage tank, road- or rail-tanker, or the like that contains a hazardous chemical. Pipes or piping systems are not considered to be containers.

Corneal conjunctivitis:

Burns to the transparent membrane covering the eyeball and lining of the eyelids.

Corrosive:

A material that causes visible destruction or irreversible alterations in tissue at the site of contact.

Cutaneous:

Of or relating to skin.

Danger:

A danger is anything which may cause injury to persons or damage to property.

Dangerous to the environment:

Descriptive of a substance or preparation that presents an acute or a chronic danger to one or more components of the environment

dB(A):

dB(A) is the unit of measurement of sound pressure level.

Decomposition:

Breakdown of a material or substance (by heat, chemical reaction, electrolysis, decay or other processes).

Defatting:

The removal of natural oils from the skin by a fat-dissolving solvent.

Deflagration:

To burn rapidly with intense heat and sparks being given off.

Dehydration:

The removal of water from a substance. A condition that results from an excessive loss of body fluids. Abnormal depletion of bodily water.

Denominator:

The lower portion of a fraction. Epidemiologists use fractions to calculate rates, or ratios. The denominator is usually the population at risk, although it may also be a measure, such as person-time, that quantifies the population's exposure.

Dermal:

Of or pertaining to the skin.

Dermal toxicity:

Toxic effects resulting from skin exposure to a substance.

Dermal sensitisation:

A hypersensitivity response of the skin resulting from repeated contact with an allergenic substance.

Dermatitis:

Inflammation of the skin often characterised by oozing, redness and itching.

Detonation:

To explode with sudden force.

Disability/Disablement:

The term "disability" refers to an impairment, which prevents the person from accomplishing certain tasks, or from performing an occupation, thereby impacting on his/her ability to live a normal life, or to earn an income.

Distribution:

The complete summary of the frequency and pattern of the values or categories of a measurement. In epidemiology, distribution is the frequency and pattern of health-related characteristics and events in a population. Classically described in terms of time place and person/ population.

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. Units of measure for dosage may vary but are usually given as milligrams of chemical per kilogram of body weight (mg/kg) or milligrams per meter square so that dosages can be compared. The quantitative dosage as well as temporal patterns, (schedule, duration and frequency), and how the route by which the dose is administered are all important parameters in predicting toxic effect.

Downwind:

In the direction toward which the wind is blowing in relation to the object or area in question. See also upwind.

Dry chemical powder:

A powdered fire extinguishing agent.

Dusts:

Solid particles suspended in air generated by a mechanical process such as crushing, grinding, abrasion or blasting.

Employee Assistance Programme (EAP):

This is the delivery of support services for employees that are functioning sub-optimally due to physical, psychological and social problems, and include counselling, training, rehabilitation, and the mobilisation of statutory bodies where necessary.

Employee Benefits & Curative Care:

This includes matters such as pension or provident fund provision, statutory entitlements, such as sick leave, perinatal leave, medical aid, hospital insurance and other negotiated benefits.

EEC Hazard classification:

Hazard and safety information as provided on the label (symbols and R & S phrases). Symbol - Pictogram appearing on user labels for packaged goods, also characterised by a letter (e.g. picture of flame and F+: very flammable substance).

EINECS:

The European Inventory of Existing Chemical Substances. A list of chemical substances identified by CAS and EINECS numbers that were marketed in the European Community between January 11971 and September 18, 1981

ELINICS:

A list of approximately 400 chemicals identified by EINECS numbers, established with the European Community from September 18, 1981 to June 30,1990. The list was published on May 29, 1991 and is a supplement to EINECS. Additional supplements will be added as necessary.

Elimination:

Getting rid of (a specific hazard).

Engineering control measures:

Engineering control measures are control measures that remove or reduce exposure of persons at the workplace by means of engineering measures, suc as isolation, enclosure and ventilation.

Epidemic:

The occurrence of more cases of a particular type of disease, chronic condition, or injury than expected in a given area, or among a specific group of people, over a particular period of time. (Think miles, many people, and months). An Outbreak is a confined epidemic, in time, place, and population. In the public's mind, "epidemic" has a far more serious connotation than "outbreak." A Pandemic is an epidemic occurring over a very wide area (several countries or continents) and usually affecting a large proportion of the population. An endemic health condition is a disease, chronic condition, or type of injury that is constantly present in a given geographic area or group.

Epidemiology:

The study of the distribution and determinants of health conditions or events in populations, and the application of this study to control health problems. The study of disease occurrence and causes in human populations. Occupational epidemiology is the study of the distribution and determinants of health in working humans. ( Analytic Epidemiology. The aspect of epidemiology concerned with why and how a health problem occurs. Analytic epidemiology uses comparison groups to provide baseline data so that associations between exposures outcomes can be quantified and hypotheses about the cause of the problem can be tested. (Descriptive epidemiology. The aspect of epidemiology concerned with gathering, organizing, and summarizing data on "person" (Who is ill?), "time" (When did they become ill?), and "place" (Where could they have been exposed to the illness?). This information is then used to conduct analytic epidemiology.

Eschar:

A thick crusting or scabbing on the skin.

Evaluation:

Systematic and objective examination of activities to determine how relevant and effective they are.

Explosive:

A chemical that causes a sudden, almost instantaneous release of pressure, gas and heat when subjected to sudden shock, pressure or high temperature.

Explosive limits:

The range of concentration of a flammable gas or vapour (percent by volume in air) in which explosion can occur if an ignition source is present.

Exposure:

The process of being exposed to something that is around; exposure can affect people in a number of different ways

Exposure limits:

Limit set to minimise occupational exposure to a hazardous substance.

Extinguishing agent:

Media suitable for controlling or putting out a fire, when properly applied.

Extremely flammable gas:

A gaseous substance or preparation that is flammable when in contact with air at ambient temperature and pressure.

Extremely flammable liquid:

A flammable liquid substance or preparation that has an initial boiling point not exceeding 35 °C.

ºF:

Degrees Fahrenheit: T(°C) = [T(°F)-32] x 5/9

Fatal:

Causing death; deadly.

Fibrosis:

A condition marked by the abnormal increase in the amount of fibrous connective tissue in an organ or tissue.

Fire point:

The lowest temperature at which a material can evolve vapours fast enough to support continuous combustion.

First degree burn:

A mild burn, characterized by pain and reddening of the skin.

Fit for work:

The term "medically fit for work" means that the person has been medically assessed and found to be suitable for the occupation’s Occupational Risk Exposure Profile (OREP), and that the person meets the relevant medical requirements, as recorded in the linked Worker Allocated Surveillance Programme (WASP).

Flammable:

Said of a material which is easily ignited.

Flammable liquid:

A liquid substance or preparation that has a closed-cup flash point not exceeding 60,5 ºC and a boiling point not exceeding 35 ºC.

Flash point:

The minimum temperature at which a liquid gives off sufficient vapour to form an ignitable mixture with air.

Foetal:

Of or pertaining to a foetus. The unborn young of an animal while still in the uterus.

Freezing point:

The temperature at which a liquid substance changes to a solid state.

Frost bite:

Damage to tissues resulting from exposure to extreme cold or contact with extremely cold liquids or objects.

Frothing:

Bubbles formed on or in a liquid; foaming.

Fumes:

Fumes are formed by processes such as sublimation or condensation and is the term generally applied to particles condensed from the gaseous state (e.g. metal fumes, polymer fumes).

Gas:

A substance which may be compressed, liquefied or dissolved under pressure.

Gastric lavage:

The irrigation or washing out of the stomach by means of a gastric tube.

Gastrointestinal disturbances:

A general term used to describe any symptoms referrable to the stomach or intestines such as nausea, vomiting, cramping and/or diarrhoea.

General ventilation:

Ventilation designed to keep the workplace comfortable.

g/kg:

Grams per kilogram. An expression of dosage used in toxicology testing, to indicate the grams of substance dosed per kilogram of animal body weight.

Harmful:

A substance or preparation capable of causing death or acute or chronic damage to health if inhaled or ingested or absorbed through the skin

Hazard:

A physical, chemical, biological, ergonomic or psychosocial agent that can cause disease or ill-health. Related words are: ( Agent. A factor that is essential for a disease, chronic conditions, or injury to occur. In occupational health we divide classify these into the five hazard classes. In theory, agents can cause a health problem by being introduced, being present in excess, or being present at deficient levels. ( Determinant. Any factor that brings about change in a health condition or in other defined characteristics. ( Environmental factor. An extrinsic factor, such as geology, climate, insects, sanitation, or health services, which affect an agent and the opportunity for exposure. ( Exposure. Coming into contact with a cause of, or possessing a characteristic that is a determinant of, a particular health problem. ( Exposed group. A group whose members have had contact with a cause of, or possess a characteristic that is a determinant of, a particular health problem. ( Host factor. An intrinsic factor (e.g., age, race, sex, behaviours) that influences an individual's exposure, susceptibility, or response to an agent. ( Risk factor. An aspect of personal behaviour or lifestyle, an environmental exposure, or a hereditary characteristic that is associated with an increase in the occurrence of a particular disease, chronic condition, or injury. A protective factor is one which decreases the occurrence of the outcome.

Hazard identification:

The identification of the inherent adverse effects of a substance or preparation.

Hazardous Chemical Substance (HCS):

Hazardous chemical substance is any toxic, harmful, corrosive, irritant or asphyxiant substance, or a mixture of such substances for which an occupational exposure limit is prescribed or which creates a hazard to health.

Hazard warning:

Any words, pictures, symbols, or combination thereof appearing on a label or other appropriate form of warning which convey the hazards of the chemical(s) in the container(s).

Health:

A state of complete physical, mental, and social well-being and not merely the absence of disease or other infirmity. Health indicator. Any of a variety of measures (e.g., mortality rate) that indicates the state of health of people in a defined population.

Health hazard:

A chemical for which there is statistically significant evidence based on at least one study conducted in accordance with established scientific principles that acute or chronic health effects may occur in exposed employees.

Health Promotion and Wellness (HP&W) Programme:

This is the term which describes the coordinated activities that aim for a state of health that exceeds the absence of disease, and seeks to achieve optimal mental, social and physical function.

Hearing protectors:

Hearing protectors are ear muffs or earplugs of a type approved by the Chief Inspector.

Highly flammable liquid:

A liquid substance or preparation that has a closed-cup flash point of less than 23 ºC and a boiling point exceeding 35 ºC.

Hydrocarbon:

Compounds composed solely of carbon and hydrogen.

Hygiene:

The principles and practice of maintaining health. "Occupational Hygiene is the discipline of anticipating, recognising, evaluating and controlling health hazards in the working environment with the objective of protecting worker health and well-being and safeguarding the community at large" (IOHA definition). These hazards may be physical, chemical, biological, ergonomic or psychosocial, and may cause injury, illness, impairment, or affect the well-being of workers and members of the community.

Hygroscopic:

Said of a substance which has a capacity to absorb water from the atmosphere.

IATA-DGR and ICAO-TI:

International Air Transport Association (IATA) Dangerous Goods Regulations (DGR) and UN International Civil Aviation Organization (ICAO) Technical Instructions for the Safe Transport of Dangerous Goods by Air (TI). The IATA Dangerous Goods Regulations is a "field manual" version of the ICAO Technical Instructions. Written and edited by airline dangerous goods experts, the Dangerous Goods Regulations presents the requirements for shipping dangerous goods by air in a user friendly, easy to interpret format. It also includes additional information which can assist shippers in making sure their consignments are in compliance and will be accepted quickly and easily by the airlines.

IATA class:

A number corresponding to one of the nine classes of cargo defined in the IATA Dangerous Goods Regulations.

IATA subsidiary risk(s):

The code for any subsidiary risk (i.e. risk which is secondary but classifiable).
For example, Ammonium Polysulphide Solution (UN number 2818) is listed as a Class 8 substance. This classification denotes a corrosive substance. Ammonium Polysulphide also has a subsidiary hazard: Class 6.1 which tells you that it is toxic. Appropriate labels for both hazards should be displayed on the package.
To deal with goods having multiple risks a `subsidiary risk' classification is used together with the principal hazard classification.

IATA shipping name:

The proper shipping name of the substance, material or article, and any known and commonly used alternative names (synonyms).

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.

Ignition source:

Anything that provides beat, spark or flame sufficient to cause combustion and/or explosion.

IMO/IMDG:

First published in 1965, the International Maritime Dangerous Goods Code (IMDG Code) published by the International Maritime Organization (IMO) has become the standard guide to all aspects of handling dangerous goods and marine pollutants in sea transport. The Code is designed to assist in compliance with legal requirements regarding the carriage of dangerous goods by sea of the International Convention for the Safety of Life at Sea (SOLAS Convention).

IMDG class number:

A number corresponding to one of the nine classes of cargo defined in the IMO International Maritime Dangerous Goods Code (IMDG Code).

IMDG EMS number:

Emergency Procedures for Ships Carrying Dangerous Goods (EMS), a supplement to the IMDG Code.

IMDG MFAG table number:

Medical First Aid Guide for use in accidents involving dangerous goods. It is intended to provide advice necessary for diagnosis and treatment of chemical poisoning.

IMDG marine pollutants:

Materials harmful to the marine environment are designated as MARINE POLLUTANT in the Code.

IMDG packaging group:

The principle of dividing dangerous goods into three packaging groups according to the degree of danger they present,i.e.Packaging group I: goods presenting great danger;Packaging group II: goods presenting medium danger; and Packaging group III: goods presenting minor danger.

IMDG shipping name:

The proper shipping name of the substance, material or article, and any known and commonly used alternative names (synonyms).

Impairment:

The term "impairment" refers to any loss or abnormality of psychological physiological or anatomical structure or function. I PREFER THIS : WHO ICDIH definition of impairment -. link

Incidence:

A rate that measures the frequency with which a health problem, such as a new injury or case of illness, occurs in a population.
Incidence proportion: The number of new cases occurring in a population during a given period of time, divided by the total population at risk during that time.
Incidence rate: The number of new cases occurring in a population, divided by the person-time at risk.

Illuminance:

Illuminance is the intensity of light falling on a surface, measured in lux.

Illuminance meter:

An instrument used for measuring illuminance.

Impervious:

Said of a material which is incapable of being penetrated by a substance.

Ingestion:

The process of taking a substance into the body through the mouth.

Inhalation:

The process of breathing in.

Inhibitor:

A substance which is added to another substance to prevent an unwanted chemical reaction from occurring.

Irritant:

A substance which will cause an inflammatory response or reaction of the eye, skin or respiratory system.

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.

Latency period:

The time period between the exposure and the first signs of disease.

LC50:

Lethal Concentration 50%; the concentration of a material in air which on the basis of laboratory tests, is expected to cause 50% mortality in a group of test animals when administered as a single exposure.

LD50:

Lethal Dose 50%; a single dose of material which, on the basis of laboratory tests, is expected to cause 50% mortality in a group of test animals when administered as a single exposure.

Leq:

Leq (equivalent noise level) is the value of the equivalent continuous sound level which would deliver the same amount of sound energy as the actual fluctuating sound, measured over the same time period.

LEL or LFL:

Lowest Explosive Limit or Lower Flammable Limit.

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:

Suction - based ventilation system designed to remove pollutants from the air at source.

luminaire:

A luminaire is a light fitting which supports a lamp and provides it with electrical connections.

lux:

The lux, (lx) is the SI unit of illuminance.

lux meter:

An instrument used to measure the amount of light falling on a surface.

Material Safety Data Sheets:

Material Safety Data Sheets (MSDS) are documents used to convey information about safe use of substances to the user. MSDS contains information on the identity, chemical and physical properties, potential health effects, and precautions for the safe use and handling of substances.

Medically unfit:

The term "medically unfit" refers to the failure to meet the specific inherent requirements of an occupation due to the presence of a medical condition that is an exclusion for the relevant occupation, or due to a lack in the capacity (physical or mental) to perform the work, to the required standard.

Medical surveillance program:

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

Melting point:

The temperature at which a solid substance changes to a liquid state.

mg/kg:

Milligrams per kilogram. An expression of toxicological dose.

mg/m³:

Milligrams per cubic metre; a unit for measuring concentrations of particulates or gases in the air (a weight per unit volume).

mist:

Liquid droplets suspended in the air.

mm Hg:

Millimetres (mm) of mercury (Hg). Unit of pressure. Normal atmospheric pressure = 760 mm Hg.

Mortality rate:

A measure of the frequency of occurrence of death in a defined population during a specified time interval. Mortality rates can be given as age-adjusted, age-specific, cause-specific, or crude. The crude mortality rate is a population's mortality rate from all causes of death.

Mucous membrane:

A thin layer of mucous-secreting tissue covering a body surface or lining an organ. For example: the nose, stomach, intestines and bronchial tubes.

Mutagen:

A substance or agent capable of altering the genetic material of a living cell.

Nausea:

An unpleasant sensation, often culminating in vomiting.

Natural history of disease:

The course of a disease from the time it begins until it is resolved.

Neutralize:

To render chemically neutral or harmless; neither acid nor base.

Noise zone:

A noise zone is an area where the equivalent noise level is equal to or exceeds 85 dB(A).

Non combustible:

A material which will not ignite, burn, support combustion or release flammable vapours when subjected to heat or fire.

N.O.S.:

Abbreviation for "Not Otherwise Specified". Used as a collective entry in transport regulations to which substances may be assigned if they are not mentioned by name.

Notifiable disease:

A disease that, by law, must be reported to public health authorities upon diagnosis. Lung cancer is one such disease in occupational health.

Numerator:

The upper portion of a fraction. Typically the number of people with disease.

Occupational:

Related to the workplace.

Occupational disease:

Any disease caused by exposures in the workplace.

Occupational Health Nurse Practitioner:

This means a registered nurse who holds a qualification in occupational health, recognised as such by the South African Nursing Council as referred to in the Nursing Act, 1978 (Act No. 50 of 1978).

Occupational Health (OH) Programme:

This is the science of work-related injury and illness prevention, incorporating the disciplines of Occupational Hygiene, Safety and Medicine, through various strategies, including risk assessment and risk control by means of engineering away hazards, and monitoring for early signs of failure of these controls.

Occupational Hygiene Assistant:

This means a person with suitable training that will conduct the activities required of an Occupational Hygiene Programme, under the supervision and guidance of an Occupational Hygienist.

Occupational Hygienist:

This means a person who holds a qualification in occupational health recognised as such by the South African Occupational Hygiene Association, and who meets the requirements of an approved Inspection Authority, as prescribed by South African Law.

Occupational Medical Practitioner:

This means a medical practitioner as defined in the Medical, Dental and Supplementary Health Service Professions Act, 1974 (Act No. 56 of 1974), who holds a qualification in occupational medicine or an equivalent qualification which qualification or equivalent is recognised as such by the South African Medical and Dental Council referred to in the said Act.

Occupational Exposure Limit:

The Occupational Exposure Limit (OEL) is a limit value set by the Minister of Labour for a stress factor in the workplace as revised from time to time by notice in the Government Gazette.

OEL-CL:

Abbreviation for Occupational Exposure Limits - Control Limits.

OEL-RL:

Abbreviation for Occupational Exposure Limits - Recommended Limits.

Occupational hygiene:

Occupational hygiene means the anticipation, recognition, evaluation and control of conditions arising in or from the workplace, which may cause illness or adverse health effect to persons.

Ocular:

Affecting the eye.

Odds ratio:

A measure of association used in comparative studies to quantify the relationship between an exposure and a health outcome; also known as the cross-product ratio.

Oedema:

The presence of abnormally large amounts of fluid in the tissue spaces of the body. May be visible as swelling of a body part such as the legs or face.

Olfactory:

Relating to the sense of smell.

Oral:

Relating to the mouth.

Oral LD50:

Oral Lethal Dose 50%; the concentration of a substance, orally administered which will produce 50 percent mortality in the animals tested.

Oral toxicity:

Adverse effects which result from taking a substance into the body via the mouth.

Oxidizing agent:

A chemical other than a blasting agent or explosive that initiates or promotes oxidation in other materials, possibly causing fire either of itself or through the release of oxygen or other gases.

Outcome, or disease, or disease outcome:

Injury, illness, impairment, or changes in the well-being of workers. Any or all of the possible results that may stem from exposure to a causal factor or from preventive or therapeutic interventions. All identified changes in health status that result from the handling of a health problem.

Pa (Pascal):

The SI unit of pressure. The normal atmospheric pressure = 101.3 kPa

Paralysis:

Partial or complete loss of function of a sense (such as smell) or partial or complete loss of motor function of a part of the body.

Partition Coefficient (n-octanol/water):

Distribution coefficient used to evaluate the harm the substance can cause to environment. Higher values indicate higher chance of accumulation of the substance in biological material.

Pathological changes:

Abnormal structural and/or functional changes in a body caused by a diseased state or exposure to a toxic chemical.

PEL:

Permissible Exposure Limit. May be a Time Weighted Average (TWA limit) or a "ceiling" concentration exposure limit.

Personal hygiene:

The practice of principles that maintain personal health, e.g. personal cleanliness.

pH:

Numerical logarithmic scale from 0 to 14 indicating whether a product is acid (pH < 7), alkaline (pH > 7) or neutral (pH = 7).

Primary Health Care (PHC) Programme:

The Primary Health Care (PHC) Programme is the delivery of first-level medical interventions, including curative as well as preventive, for injured and ill employees at work, and is implied to be an on-site activity.

Physical hazard:

A chemical for which there is scientifically valid evidence that it is: a combustible liquid, a compressed gas, explosive, flammable, an organic peroxide, an oxidising agent, pyrophoric, unstable (reactive) or water-reactive substance.

PMCC:

Pensky Martens Closed Cup: a flash point test method.

Polymer:

A high molecular weight material formed by chemically joining together five or more molecules (monomers).

Polymerisation:

A chemical reaction in which a large number of relatively simple molecules (monomers) combine to form a large chainlike molecule. A hazardous polymerisation is a reaction which takes place at a rate which releases large amounts of energy.

Polymerisation:

Polynuclear aromatic hydrocarbons:

Organic compounds usually composed of three or more aromatic rings. Some of these compounds (esp. 4-6 ring compounds) are capable of causing skin tumour formation. Also known as PNA's or PAH's.

Population:

The total number of inhabitants of a given area or country. In sampling, the population may refer to the units from which the sample is drawn, not necessarily the total population of people. A population can be a particular group at risk, such as everyone who is engaged in a certain occupation. A population need not be human, eg. farms, households, folders. A group sharing certain common characteristics, about whom inferences can be made.

Potential hazard:

Something that may be hazardous.

Pour point:

The lowest temperature at which a liquid will flow or pour.

ppb:

Parts per billion : a unit for measuring the concentration of a gas or vapour in air; parts (by volume) of the gas or vapour in a billion parts of air. Also used to indicate the concentration of a particular substance in a solution or solid.

PPE:

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

ppm:

Parts per million; a unit for measuring the concentration of a gas or vapour in air; parts (by volume) of the gas or vapour in a million parts of air. Concentration of a particular substance in a liquid or solid.

Preparation:

A mixture or solution composed of two or more substances.

Prevalence:

The number or proportion of cases or events or conditions in a given population, as measured at a point in time, e.g. if measured now, the number or proportion of people now who have diabetes.

Proportion:

A ratio in which the numerator is included in the denominator; the ratio of a part to the whole, expressed as a decimal fraction (e.g. 0.2), a fraction (1/5), or a percentage (20%). It is a special ratio, where the value is between 0 and 1.

Protective clothing:

Clothing designed to provide protection to the wearer against contamination from chemical, biological, radiation or physical hazards.

psi:

Pounds per square inch. An obsolete unit of pressure. Normal atmospheric pressure = 14.7 psi = 101.3 kPa

Pulmonary oedema:

The abnormal accumulation of fluid in the tissue and air spaces of the lungs.

Pyrolysis:

The breaking apart of complex molecules into simpler units by the use of heat, as in the pyrolysis of heavy oil into gasoline.

Pyrophoric:

A chemical that will ignite spontaneously in air.

Radioactive:

The property of an isotope or element which is characterised by giving off radiant energy in particles or rays by the disintegration of atomic nuclei.

Rate:

A ratio with an implicit time-element, often multiplied by 10n.

Ratio:

The value obtained by dividing any one quantity by another, e.g. female: male ratio. Percentages, proportions and rates are all ratios.

Reactivity:

The tendency of a substance to undergo a chemical change with the release of energy. Undesirable effects (pressure build-up, temperature increase, formation of noxious, toxic or corrosive by-products) may occur because of a reaction to heating, burning, direct contact with other materials or other conditions when in use or in storage.

Reducing agent:

A material which is oxidised or which allows easy oxidation.

Reproductive chemical hazard:

A substance or preparation that, if inhaled or ingested or absorbed through the skin, produces or increases the incidence of non-heritable. adverse effects in the progency, or an impairment of male or female reproductive functions or capacities (or any combination of these).

Respiratory hazard:

Hazards to the body's breathing system.

Respiratory protection:

Devices for use in conditions exceeding the exposure levels, which when properly selected, maintained, and operated by the user, will protect the user's respiratory system from exposure to airborne contaminants by inhalation. Respiratory protective equipment are devices which are worn over at least the mouth and nose to prevent the inhalation of air which is not safe.

Respiratory system:

The breathing system; includes the lungs and the air passages (trachea or windpipe, larynx, mouth and nose) to the air supply outside the body.

RID:

Règlement concernant le transport International ferroviaire des marchandises Dangereuses (Regulations concerning the International Carriage of Dangerous Goods by Rail) by the Organisation Intergouvernementale pour les Transports Internationaux Ferroviaires (OTIF) - Intergovernmental Organisation for International Carriage by Rail

Risk:

(i) The probability that an individual will be affected by, or die from, an illness or injury within a stated time or age span, or that serious damage to property will occur. (ii) In risk assessment it is often used to refer to likelihood of exposure multiplied by severity of impact. The answer is often categorical: negligible, low, medium, high, etc. (iii) In epidemiology, it has the meaning of incidence proportion, i.e. the proportion of a cohort of workers affected when they are followed up over time.

Routes of entry:

The different ways hazardous agents can get into the body.

R phrases:

Risk phrases : a set of numbered standard sentences which appear on user labels for packaged goods (e.g. R23: Toxic by inhalation).

SACAA:

South African Civil Aviation Authority.

SA-CATS-DG:

South African Civil Aviation Technical Standards Relating to the Conveyance of Dangerous Goods

SETA:

Setaflash Closed Tester; a flash point test method.

"Safe" levels:

Levels of exposure to substances below which there will not be a health risk to workers.

Sample:

A selected subset of a population. A sample may be random or non-random and representative or non-representative.

Second degree burns:

A burn that is more severe than a first degree burn, and is often characterized by blistering, reddening of the skin, oedema and destruction of the superficial tissue.

Short-term OEL-RL

The concentration of airborne dust, fumes or vapours to which workers can be exposed continuously for a short period without suffering from irritation, chronic or irreversible tissue damage or narcosis of sufficient degree to increase the likelihood of accidental injury, impair self-rescue or materially reduce work efficiency.

Simple asphyxiant:

A substance which induces a deficiency in the supply of oxygen. Nitrogen, methane and acetylene are examples.

Skin lesion:

An abnormal change in the structure of the skin due to injury or disease.

Solubility in water:

The percentage of a material (by weight) that will dissolve in water at a specified temperature.
negligible or nil - less than 0.1 %
slight - 0.1 to 1.0%
moderate - 1 to 10%
appreciable - more than 10%
complete - soluble in all proportions.

Solution

Uniformly dispersed mixture. All solutions are composed of a solvent (water or other fluid) and the dissolved substance, called the "solute".

S phrases:

Safety phrases : a set of numbered standard sentences which appear on user labels for packaged goods (e.g. S 15: Keep away from heat).

Specific gravity (S.G.):

The ratio of the weight of material to be weight of an equal volume of water usually at 20 ºC, unless otherwise specified. Specific gravity of water = 1.

STEL:

Abbreviation for Short Term Exposure Limits.

Storage depot:

A storage depot is a site or tissue which sequesters a toxin without a deleterious effect. Examples include sequestration of lead into the calcium hydroxyapatite matrix of bone cortex and DDT or other organochlorines entry and storage in fatty tissues. Such storage depots allow for decreased bioavailabity of a sequestered toxin, biologic persistence with chronic low level exposure, (equilibrium between the storage depot and blood stream), decreased excretion and biologic persistence.

Study:

An epidemiological study often compares two groups of people who are alike except for one factor such as exposure to a chemical or the presence of a health effect. The investigators try to determine if the factor is associated with the health effect.
Analytic study: A study examining associations between groups, typically looking for causality. The common types of analytic study are cross-sectional, case-control and cohort studies.
Descriptive study:. A study describing the existing distribution of variables, without regard to causal or other hypotheses. Classically, there is no comparison group. Examples are case studies, case series, and descriptive cross-sectional studies.
Interventional study: An analytical study where the investigators systematically and intentionally change the exposure status of the subjects, by e.g. giving therapy, or removing a risk factor.
Observational study:. An analytic epidemiologic study in which there is no intervention. Changes or differences in one characteristic are studied in relation to changes or differences in others.
Case-control study: An analytic observational study where cases (with the disease or outcome) are compared with suitable controls (without the disease or outcome), by looking at their (historical or current) exposures. The starting point occurs after the onset of the disease or outcome, and looks back to find postulated causal factors. It's like taking snapshots of some sick and some healthy family members, and then paging through the family album looking for previous snapshots of those same family members, looking for clues as to why they got sick or not. A study in which people with a disease (cases) are compared to people without the disease (controls) to see if their past exposures to chemicals or other risk factors were different.
Cohort study: An analytic observational study where a well-defined group of disease free people who have had a common experience or exposure are followed up through time, looking for disease outcomes. The starting point occurs before the onset of the disease or outcome, having already identified postulated causal factors. It's like a number of snapshots taken at periodically of all family members who could be present, looking for clues as to why some got sick. A study in which a group of people with a past exposure to chemicals or other risk factors are followed over time and their disease experience compared to that of a group of people without the exposure.
Cross-sectional study: (Prevalence study.) A study that examines the relationship between exposures and outcomes prevalent in a defined population, at a defined point in time. The start and endpoint are the same, and disease and postulated causal factors are measured simultaneously. It's like a single snapshot of everyone in the family who could be gathered for the photo, looking for clues as to why some are sick.

Substance (chemical):

Chemical elements and their compound, either in the natural state or obtained by a production process, including any additive necessary to preserve the stability of the product and any impurity derived inevitably from the process used, but excluding any solvents that can be separated without affecting the stability of the substance or changing its composition.

Substance identity number:

The substance identification numbers are identical with the UN Numbers, except for those in the 7000 series. These are specific to the UK and are used where there is no suitable UN number.

Substance identity number:

Replacing particularly hazardous chemicals or work processes by safer ones.

Symbol:

Pictogram appearing on user labels for packaged goods, also characterised by a letter (e.g. picture of flame and F+: very flammable substance).

Symptom:

Abnormality in the body which is noticeable only to the person experiencing it and may indicate poisoning or disease.

Synergism:

The term used when exposure to two chemicals at the same time produces a much more harmful effect than the sum of the effects of exposure to the individual chemicals.

Systemic toxicity:

The adverse effects caused by a substance, affecting the body in a general rather than a local manner.

Target organs/site:

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. The target site refers to the location(s) at which adverse effects occur. Toxicity may be relatively specific to an organ system or even cell type therein but generally toxicity will occur at several sites. Patterns of physiologic response, (syndromes), may give clues as to toxic etiologies. An example would be lead which at very low dosages causes subtle neuropsychiatric effects which with ongoing exposure become permanent and which as dose increases will affect bone marrow hemoglobin production and renal function.

TCC:

Tag (Tagliabue) Closed Cup: a flash point test method.

Teratogen:

A substance that upon exposure to the parent causes malformations and/or alterations in the appearance or function of the foetus.

TLV:

Threshold Limit Value: a term used to express the airborne concentration of a material to which nearly all persons can be exposed day after day, without adverse effects.
TLC-C: Ceiling Exposure Limit, the concentration that should not be exceeded, even momentarily.
TLV-STEL: Short Term Exposure Limit, or maximum concentration for a continuous 15-minute exposure period (maximum of four such periods per day, with at least 60 minutes between exposure periods, and provided that the daily TLV-TWA is not exceeded).
TLV-Skin: (Listed substance followed by the designation "skin"): The skin designation refers to the potential contribution to the overall exposure by the cutaneous route, including mucous membranes and the eye. Exposure can be either by airborne or direct contact with the substance. This "attention calling" designation suggests appropriate measures be taken to prevent skin absorption. The TLV is not invalidated.
TLV-TWA: The allowable Time Weighted Average concentration for a normal eight hour workday or 40 hour work week. May also be adjusted for extended work shifts.

TOCC:

Tag (Tagliabue) Open Cup: a flash point test method.

Toxicant, or poison:

Any agent capable of producing a deleterious effect in a biological system. As per Paracelsus’ axiom, all substances are potentially poisonous, it is the dosage that determines the toxicity.

Toxicity:

Inherent capacity to produce injury. Adverse effects resulting from overexposure to a material, generally via the mouth, skin, eyes or respiratory tract. It is thus the potential to cause damage to humans and experimental animals.

Toxicodynamics:

The study of the relationship between the dose of the toxic substance that enters the body and the measured response or adverse effect.

Toxicokinetics:

The study of the movement of toxic substance within the body. It refers to the absorption, distribution, metabolism and excretion of xenobiotics (substances "foreign" to the body). Toxicokinetics takes into consideration differences in susceptibility among individuals. The factors to consider in these processes are those of (1) bioavailability, (2) absorption, (3) distribution, (4) metabolism and (5) excretion and how they may be affected by genomic or environmental factors or combinations thereof. It also encompasses the relationship between the dose that enters the body and the level of the toxic substance in any biological sample.

Toxicology:

The study of the adverse effects of a toxicant on living organisms. Toxicology is an applied science that incorporates biology, chemistry, physiology, pathology, physics, statistics, and sometimes immunology or ecology to help solve problems in forensic medicine, public health, industrial hygiene, veterinary medicine, pharmacy and pharmacology, as well as giving basic insight into how an organism functions. It includes an evaluation of safety associated with exposure to various agents.

Toxic substance or preparation:

A substance or preparation that is capable, in small quantities, of causing dealth or acute or chronic damage to health if inhaled or ingested or absorbed through the skin.

Toxic substance or preparation:

Short in duration.

Transport Emergency Card (Tremcard):

Instructions on how to deal with emergencies involving hazardous chemicals, transported by road.

Tumour:

Abnormal mass of tissue.

Time Weighted Average:

The time-weighted average (TWA) is the average of a number of representative measurements that are taken over a period of time and that are calculated as follows:
TWA = (x₁t₁ + x₂t₂ + ... + x_nt_n) / (t₁ + t₂ + ... + t_n)
where x₁, x₂, etc. are the observed measurements during corresponding periods t₁, t₂, etc.

TWA OE-REL:

The time-weighted average concentration of airborne dust, fumes or vapours for a conventional 8 hour workday and a 40 hour workweek, to which it is believed that nearly all workers can be repeatedly exposed, day after day, without adverse effect.

Two-by-two table:

A table with 4 cells, which is the basic numerical method used to compare occurrence of disease in different groups. The groups are simply divided into those with and without exposure and those with and without disease. The 4 cells are labeled a, b, c and d. Cell a contains those with both exposure and disease, and cell d contains those free of both exposure and disease.

Ulcer:

A lesion (wound/injury) on the surface of the skin or mucous surface.

Unconscious:

Not conscious : incapable of responding to sensory stimuli.

UN number:

United Nations substance numbers are four-digit numbers, which have been assigned by the United Nations Committee of Experts on the Transport of Dangerous Goods, to individual substances (e.g. sulphuric acid) or groups of similar substances (e.g. carbamate pesticides). The numbers are primarily intended to facilitate the identification of substances without the need for a knowledge of the language in which the chemical name is printed. They have also proved to be of great value for emergency services in the correct relaying of long or complex names of substances, thus allowing error-free identification.

Unstable:

Tending toward decomposition or other unwanted chemical change during normal handling or storage.

Unstable (Reactive):

A chemical which in the pure state, or as produced or transported, will vigorously polymerise, decompose, condense, or will become self-reactive under conditions or shocks, pressure or temperature.

Upper Flammable Limit (UFL):

The highest concentration of a flammable vapour or gas in air (usually expressed in percent by volume) above which propagation of a flame will not occur in the presence of an ignition source. Also called upper explosive limit or UEL.

Upwind:

In the direction from which the wind is blowing. Also see downwind.

Vapour density:

The relative weight of a vapour compared to an equal volume of air (indicates whether vapours will rise or sink). 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:

Pressure of saturated vapour above liquids or solids (usually provided at 20 ºC). The higher the vapour pressure, the higher the concentration will be in unventilated spaces.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.

Variable:

Any characteristic or attribute that can be measured and can have different values.

Very toxic substance or preparation:

A substance or preparation that is capable, in very low concentrations, of causing death or acute or chronic damage to health if inhaled or ingested or absorbed through the skin.

Viscous:

Having resistance to flow.

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.

Waste, chemical:

Unusable products from chemical and metal processing operations, that contain dangerous or polluting materials that pose a threat to humans or animals or the environment if improperly disposed of.

Water reactive:

A chemical that reacts with water to release a gas that is either flammable or presents a health hazard.

Wet bulb globe temperature (WBGT):

The wet bulb globe temperature (WBGT) index is a number which characterises the thermal conditions in the environment to which that number applies.

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.

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GLOSSARY