 Hazardous substances are those that, following worker exposure, can have an adverse effect on health. Examples of hazardous substances include poisons, substances that cause burns or skin and eye irritation, and substances that may cause cancer. Many hazardous substances are also classified as dangerous goods.

 A substance is deemed to be a hazardous substance if it meets the classification criteria specified in the Approved Criteria for Classifying Hazardous Substances [NOHSC:1008(2004] (Approved Criteria).Approved Criteria for Classifying Hazardous Substances [NOHSC:1008(2004]  Substances that have been classified according to the Approved Criteria are provided in the online database called the Hazardous Substances Information System (HSIS).Hazardous Substances Information System

 Dangerous goods are substances, mixtures or articles that, because of their physical, chemical (physicochemical) or acute toxicity properties, present an immediate hazard to people, property or the environment. Types of substances classified as dangerous goods include explosives, flammable liquids and gases, corrosives, chemically reactive or acutely (highly) toxic substances.

 The criteria used to determine whether substances are classified as dangerous goods are contained in the Australian Code for the Transport of Dangerous Goods by Road and Rail (ADG Code). The ADG Code contains a list of substances classified as dangerous goods.

 State and territory workplace dangerous goods storage and handling laws also capture combustible liquids. The criteria for classifying combustible liquids are contained in Australian Standard AS1940 (The Storage and Handling of Flammable and Combustible Liquids).  Many dangerous goods are also classed as hazardous substances.

 This is the study of the effects of chemical substances on living organisms. A poison or toxin is any substance that above a certain minimum dose or level causes harm to the body. The main routes for entry of substances - inhalation through the lung, absorption through the skin (dermal) and intake through the mouth (gastrointestinal)

 These could include illness, death, asthma, lung damage and cancer, burns, rashes and dermatitis, allergies, headache, dizziness etc.

 A number of factors influence the response of an individual to a particular poisonous substance. These include: 1. The response of the individual - the body’s individual response to the substance. This is done through large scale studies using animals. These studies produce two values that are used in toxicity studies.

 LD 50 refers to the dose of poison required to kill 50% of the population. It is used as a quantitative estimation of how poisonous a substance will be if it is taken or injected into the body. Very poisonous substances have a low LD 50 ( e.g the insecticide parathion 5mg/kg ) whilst less poisonous substances have a much higher LD 50 ( e.g. alcohol 5000mg/kg )  LC 50 is similar to LD 50 except that it refers to the concentration of poison in the body required to kill 50% of the population

2. The dose The amount of poison taken into the body. It is generally expressed in mg/ kg. Time is another important consideration, for the body may be able to cope with a small dose of a substance over a period of time but by increasing the dose or shortening the time of exposure, e.g- with alcohol in binge drinking, the body may not cope resulting in death. 3. Exposure Here you must consider the period of exposure, the frequency of exposure, and the persistence of the substance or how long a substance remains in a particular place.

 In many cases poisoning occurs over a long period of time with the poison being absorbed from the environment. In this case it is the time that the individual spends in the toxic environment that determines the dose that the individual may receive.

 There are four common ways of expressing exposure standards -  1. TWA (Time Weighted Average) - this is the average concentration of a poisonous substance allowed in the air of the working environment over an eight hour day and a five day working week, which will not cause any undesirable health effects in the majority of workers.   2.TLV (Threshold Limit Values.) - similar to the TWA Basically, the larger the TWA or TLV, the less poisonous a substance is by exposure. 

 3. STEL (Short Term Exposure Limit.) - this is a fifteen minute TWA exposure limit which should not be exceeded at any time - even if the eight hour limit is within the exposure standard.   4. Peak Value - is the maximum concentration of a poisonous substance allowed in the atmosphere at any one time. This is particularly important for irritants such as ammonia or chlorine which produce pronounced acute effects.  In the absence of an exposure standard, enforce the lowest practical standard possible.

A chemical that causes visible destruction of, or irreversible alterations in, living tissue by chemical action at the site of contact.chemical A corrosive material is a highly reactive substance that causes obvious damage to living tissue. Corrosives act either directly, by chemically destroying the part (oxidation), or indirectly by causing inflammation. Acids and bases are common corrosive materials. Corrosives such as these are also sometimes referred to as caustics.chemicallyoxidationinflammationAcidsbases Typical examples of acidic corrosives are hydrochloric (muriatic) acid and sulfuric acid. Typical examples of basic corrosives are sodium hydroxide and lye.

The lowest temperature at which a liquid can form an ignitable mixture in air near the surface of the liquid. The lower the flash point, the easier it is to ignite the material.mixtureair For example, gasoline has a flash point of approximately -40 degrees C (-40 F) and is more flammable than ethylene glycol (antifreeze) which has a flash point of 111 degrees C (232 F) in closed cup tests (see below).degrees C (-40 F) flammable A closely related and less common term is fire point, the temperature at which the flame becomes self-sustained so as to continue burning the liquid (at the flash point, the flame does not need to be sustained). The fire point is usually a few degrees above the flash point.

Toxic is defined by OSHA 29 CFR App A as a chemical which falls in any of these three categories:29 CFR App A chemical 1. A chemical that has a median lethal dose (LD 50 ) of more than 50 milligrams per kilogram but not more than 500 milligrams per kilogram of body weight when administered orally to albino rats weighing between 200 and 300 grams each.chemicalLD 50milligramskilogramgrams 2. A chemical that has a median lethal dose (LD 50 ) of more than 200 milligrams per kilogram but not more than 1,000 milligrams per kilogram of body weight when administered by continuous contact for 24 hours (or less if death occurs within 24 hours) with the bare skin of albino rabbits weighing between two and three kilograms each.chemicalLD A chemical that has a median lethal concentration (LC 50 ) in air of more than 200 parts per million but not more than 2,000 parts per million by volume of gas or vapor, or more than two milligrams per liter but not more than 20 milligrams per liter of mist, fume, or dust, when administered by continuous inhalation for one hour (or less if death occurs within one hour) to albino rats weighing between 200 and 300 grams each.chemicalLC 50airparts per millionmistfumedust inhalation

A carcinogen is a substance that causes cancer (or is believed to cause cancer).cancer

A mutagen is a substance or agent that causes an increase in the rate of change in genes (subsections of the DNA of the body's cells). These mutations (changes) can be passed along as the cell reproduces, sometimes leading to defective cells or cancer. Examples of mutagens include certain biological and chemical agents as well exposure to ultraviolet light or ionizing radiation. chemical

A teratogen is an agent that can cause malformations of an embryo or fetus. This can be a chemical substance, a virus or ionizing radiation.chemical This is closely related to a fetotoxin, an agent that causes poisoning effects on a developing fetus.fetotoxinpoisoning Both fetotoxins and teratogens are reproductive toxins, substances which cause damage to one's reproductive and/or endocrine system and/or a developing fetus. reproductive toxins

A chemical, which is not corrosive, but which causes a reversible inflammatory effect on living tissue by chemical action at the site of contact.chemical corrosiveinflammatory

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