OSH Answers Fact Sheets
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ACGIH stands for American Conference of Governmental Industrial Hygienists.
The Threshold Limit Value (TLV) Committee and Ventilation Committee of the ACGIH publish exposure guidelines which are used worldwide.
An active ingredient is the part of a product which actually does what the product is designed to do. It is not necessarily the largest or most hazardous part of the product. For example, an insecticidal spray may contain less than 1% pyrethrin, the ingredient which actually kills insects. The remaining ingredients are often called inert ingredients.
Active ingredients are often used to determine which products must comply with the national Workplace Hazardous Materials Information System (WHMIS).
Acute means sudden or brief. Acute can be used to describe either an exposure or a health effect. An acute exposure is a short-term exposure. Short-term means lasting for minutes, hours or days. An acute health effect is an effect that develops either immediately or a short time after an exposure. Acute health effects may appear minutes, hours or even days after an exposure. (See also Chronic.)
An aerosol is a collection of very small particles suspended in air. The particles can be liquid (mist) or solid (dust or fume). The term aerosol is also commonly used for a pressurized container (aerosol can) which is designed to release a fine spray of a material such as paint.
Inhalation of aerosols is a common route of exposure to many chemicals. Also, aerosols may be fire hazards.
AIHA stands for American Industrial Hygiene Association.
ANSI stands for the American National Standards Institute.
The auto-ignition temperature is the lowest temperature at which a material begins to burn in air in the absence of a spark or flame. Many chemicals will decompose (break down) when heated. The auto-ignition temperature is the temperature at which the chemicals formed by decomposition begin to burn. Auto-ignition temperatures for a specific material can vary by one hundred degrees Celsius or more, depending on the test method used. Therefore, values listed in documents such as a Material Safety Data Sheet may be rough estimates. To avoid the risk of fire or explosion, materials must be stored and handled at temperatures well below the auto-ignition temperature.
Bioaccumulation describes the process by which a chemical accumulates in a living organism - either from the surrounding environment (air, water or soil) or from other sources, for example by consuming food containing the substance. See also Bioconcentration.
Bioavailability is a measurement of the degree to which a chemical in the environment can be taken up into a living organism. Reduced bioavailability, which can occur if the chemical is bound to something else, means a lower exposure.
Bioconcentration describes the process by which a chemical can build up in a living organism to levels higher than those found in the surrounding environment. For example, a fish will have a higher concentration of a chemical in its body than is present in the water it swims in. Bioconcentration refers to the uptake of the chemical from water only - not all sources of exposure to the chemical. See also Bioaccumulation.
Biodegradation is a measure of the ability of a chemical to be broken down into smaller units by living organisms. Biodegradation is a key process for the natural reduction of hazardous chemicals.
Biomagnification is the accumulation of higher concentrations of a chemical in a living organism at each successive level in the food chain. The chemical is transferred to organisms further up the food chain as they consume organisms lower in the food chain.
This is the process by which living organisms transform chemicals in the environment.
Biohazardous Infectious Material
A biohazardous infectious material is a material that contains organisms which can cause disease in humans or animals. Included in this category are bacteria, viruses, fungi and parasites. Because these organisms can live in body tissues or fluids (blood, or urine), the tissues and fluids are also treated as toxic. For example, a person exposed to a blood sample from someone with hepatitis B may contract the disease.
BOD stands for biological oxygen demand or biochemical oxygen demand. It is used as a method of determining how much contamination has entered a water supply. It is used primarily for waters which receive pollution from sewage and industrial wastes. Refers to the results of the BOD Test.
A test that measures the amount of oxygen that is consumed as microbial life decomposes organic matter in water.
The boiling point is the temperature at which the material changes from a liquid to a gas. Below the boiling point, the liquid can evaporate to form a vapour. As the material approaches the boiling point, the change from liquid to vapour is rapid and vapour concentrations in the air can be extremely high. Airborne gases and vapours may pose fire, explosion and health hazards.
Sometimes, the boiling point of a mixture is given as a range of temperatures. This is because the different ingredients in a mixture can boil at different temperatures.
If the material decomposes (breaks down) without boiling, the temperature at which it decomposes may be given with the abbreviation "dec." Some of the decomposition chemicals may be hazardous. (See also Thermal Decomposition Products.)
The time it takes a sample of solid material to burn a specified distance.
CANUTEC stands for Canadian Transport Emergency Centre, which is part of the Transport Dangerous Goods Directorate of Transport Canada. CANUTEC provides information and communications assistance in case of transportation emergencies involving dangerous goods. It is accessible in Canada by telephone, 24 hours a day, year round at (613) 996-6666 (collect).
Carcinogen, Carcinogenic, Carcinogenicity
A carcinogen is a substance which can cause cancer. Carcinogenic means able to cause cancer. Carcinogenicity is the ability of a substance to cause cancer.
When classifying materials for the workplace, under the Canadian Controlled Products Regulations, materials are identified as carcinogens if they are recognized as carcinogens by the American Conference of Governmental Industrial Hygienists (ACGIH), or the International Agency for Research on Cancer (IARC).
Under the US OSHA Hazard Communication (Hazcom) Standard, materials are identified as carcinogens if they are listed as either carcinogens or potential carcinogens by IARC or the US National Toxicology Program (NTP), if they are regulated as carcinogens by OSHA, or if there is valid scientific evidence in man or animals demonstrating a cancer causing potential.
The lists of carcinogens published by the IARC, ACGIH and NTP include known human carcinogens and some materials which cause cancer in animal experiments. Certain chemicals may be listed as suspect or possible carcinogens if the evidence is limited or so variable that a definite conclusion cannot be made.
CAS Registry Number
The CAS Registry Number is a number assigned to a material by the Chemical Abstracts Service (CAS) of the American Chemical Society (ACS). The CAS number provides a single unique identifier. A unique identifier is necessary because the same material can have many different names. For example, the name given to a specific chemical may vary from one language or country to another. The CAS Registry Number is similar to a telephone number and has no significance in terms of the chemical nature or hazards of the material. The CAS Registry Number can be used to locate additional information on the material, for example, when searching in books or chemical databases.
Depending on the context, CC can stand for closed cup, cubic centimetres or ceiling concentration.
CCC stands for Cleveland closed cup, a standard method of determining flash points.
CCOHS stands for the Canadian Centre for Occupational Health and Safety. CCOHS provides an occupational health and safety information service through answers to inquiries, publications and a computerized information service. The computerized information is available both on the internet and on CD-ROM.
See Exposure Limits for a general explanation.
CEPA stands for Canadian Environmental Protection Act.
CERCLA stands for Comprehensive Environmental Response, Compensation and Liability Act (U.S.).
The chemical family describes the general nature of the chemical. Chemicals belonging to the same family often share certain physical and chemical properties and toxic effects. However, there may also be important differences. For example, toluene and benzene both belong to the aromatic hydrocarbon family. However, benzene is a carcinogen, and toluene is not.
The chemical formula, sometimes called the molecular formula, tells which elements (carbon, hydrogen, oxygen, and so on) make up a chemical. It also gives the number of atoms of each element in one unit or molecule of the chemical. The chemical formula can be used to confirm the identity of ingredients or to indicate the presence of a potentially hazardous element.
For example, zinc yellow has the chemical formula ZnCrO4, which shows that it contains not only zinc (Zn) but also chromium (Cr).
The chemical name is a proper scientific name for an ingredient of a product. For example, the chemical name of the herbicide 2,4-D is 2,4-dichlorophenoxyacetic acid. The chemical name can be used to obtain additional information.
Chemical reactivity is the ability of a material to undergo a chemical change. A chemical reaction may occur under conditions such as heating, burning, contact with other chemicals, or exposure to light. Undesirable effects such as pressure buildup, temperature increase or formation of other hazardous chemicals may result.
(See also Dangerously Reactive Material and Reactive Flammable Material.)
CHEMTREC stands for the Chemical Transportation Emergency Centre. It is a U.S. national center administered by the American Chemistry Council (ACC) to relay pertinent emergency information concerning specific chemicals on requests from individuals. CHEMTREC has a 24-hour toll-free telephone number to help respond to chemical transportation emergencies for companies who have registered with them for this service.
Chronic means long-term or prolonged. It can describe either an exposure or a health effect. A chronic exposure is a long-term exposure. Long-term means lasting for months or years. A chronic health effect is an adverse health effect resulting from long-term exposure or a persistent adverse health effect resulting from a short-term exposure. The Canadian Controlled Products Regulations describe technical criteria for identifying materials which cause chronic health effects. These regulations are part of the Workplace Hazardous Materials Information System (WHMIS). (See also Acute.)
A test procedure used to measure the flash point of a material, using a closed cup, which prevents the vapour from escaping. A closed cup flash point is generally lower than a flash point measured using an open cup method.
CNS stands for central nervous system.
COC stands for Cleveland open cup, a standard method of determining flash points. This open cup method allows the vapours to escape, generally producing a flash point value that is higher than a flash point measured by a closed cup method.
COD stands for chemical oxygen demand. COD is the amount of oxygen used to oxidize reactive chemicals in water. It is a measure of water quality.
Coefficient Of Oil/water Distribution
The coefficient of oil/water distribution, also called the partition coefficient (abbreviated as P), is the ratio of the solubility of a chemical in an oil to its solubility in water. The P value is typically presented as a logarithm of P (log P). It indicates how easily a chemical can be absorbed into or stored in fatty tissues in the body. The P value is also used to help determine the fate of the chemical in the environment through its tendency to partition into the water, soil and living organisms.
Combustible means able to burn. Broadly speaking, a material is combustible if it can catch fire and burn. However, in many jurisdictions, the term combustible is given a specific regulatory meaning. (See Combustible Liquid.)
The terms combustible and flammable both describe the ability of a material to burn. Commonly, combustible materials are less easily ignited than flammable materials.
Under the Canadian Controlled Products Regulations (CPR), a combustible liquid has a flash point from 37.8 to 93.3 degrees C (100 to 200 degrees F) using a closed cup test. The CPR is part of the national Workplace Hazardous Materials Information System (WHMIS). The US OSHA Hazcom Standard uses a similar definition.
This range of flash points is well above normal room temperature. Combustible liquids are, therefore, less of a fire hazard than flammable liquids. If there is a possibility that a combustible liquid will be heated to a temperature near its flash point, appropriate precautions must be taken to prevent a fire or explosion.
A compressed gas is a material which is a gas at normal room temperature and pressure but is packaged as a pressurized gas, pressurized liquid or refrigerated liquid.
The Canadian Controlled Products Regulations [part of the Workplace Hazardous Materials Information System (WHMIS)] and the U.S. Hazcom standard describe technical criteria for identifying materials which are classified as compressed gases.
Regardless of whether a compressed gas is packaged in an aerosol can, a pressurized cylinder or a refrigerated container, it must be stored and handled very carefully. Puncturing or damaging the container or allowing the container to become hot may result in an explosion.
Under the Canadian Products Regulations [part of the Workplace Hazardous Materials Information System (WHMIS)], a controlled product is defined as a material, product or substance which is imported or sold in Canada and meets the criteria for one or more of the following classes:
- Class A - Compressed Gas
- Class B - Flammable and Combustible Material:
- Division 1 - Flammable Gas
- Division 2 - Flammable Liquid
- Division 3 - Combustible Liquid
- Division 4 - Flammable Solid
- Division 5 - Flammable Aerosol
- Division 6 - Reactive Flammable Material
- Class C - Oxidizing Material
- Class D - Poisonous and Infectious Material:
- Division 1 - Material Causing Immediate and Serious Toxic Effects:
- Subdivision A - Very Toxic Material
- Subdivision B - Toxic Material
- Division 2 - Material Causing Other Toxic Effects:
- Subdivision A - Very Toxic Material
- Subdivision B - Toxic Material
- Division 3 - Biohazardous Infectious Material
- Class E - Corrosive Material
- Class F - Dangerously Reactive Material
Controlled Products Regulations (CPR)
The Controlled Products Regulations are Canadian federal regulations developed under the Hazardous Products Act. They are part of the national Workplace Hazardous Materials Information System (WHMIS).
The regulations apply to all suppliers (importers or sellers) in Canada of controlled products intended for use in Canadian workplaces.
The regulations specify the criteria for identification of controlled products. They also specify what information must be included on labels and Material Safety Data Sheets (MSDSs).
A corrosive material can attack (corrode) metals or human tissues such as the skin or eyes. Corrosive materials may cause metal containers or structural materials to become weak and eventually to leak or collapse. Corrosive materials can burn or destroy human tissues on contact and can cause effects such as permanent scarring or blindness.
The Canadian Controlled Products Regulations (part of the Workplace Hazardous Materials Information System (WHMIS) and the US OSHA Hazcom Standard, specify technical criteria for identifying materials which are classified as corrosive materials for the purposes of each regulation. (See also pH.)
Metric unit of volume. Equal to one thousandth of a litre. It is a metric unit of volume equal to 1000 litres.
CU M or CU.M
This stands for cubic metre
Dangerously Reactive Material
The Canadian Controlled Products Regulations (part of the Workplace Hazardous Materials Information System (WHMIS) describes technical criteria for identifying materials which are classified as dangerously reactive. A dangerously reactive material can react vigorously:
- with water to produce a very toxic gas;
- on its own by polymerization or decomposition; or
- under conditions of shock, or an increase in pressure or temperature.
The American National Standards Institute (ANSI) defines a dangerously reactive material as one that is able to undergo a violent self-accelerating exothermic chemical reaction with common materials, or by itself.
A dangerously reactive material may cause a fire, explosion or other hazardous condition. It is very important to know which conditions (such as shock, heating or contact with water) may set off the dangerous reaction so that appropriate preventive measures can be taken.
See also the U.S. OSHA HAZCOM definitions for unstable (reactive) and water reactive.
The density of a material is its weight for a given volume. Density is usually given in units of grams per millilitre (g/mL) or grams per cubic centimetre (g/cc). Density is closely related to specific gravity (relative density). The volume of a material in a container can be calculated from its density and weight.
See General Ventilation.
Domestic Substances List (DSL)
The Domestic Substances List (DSL) was created in accordance with the Canadian Environmental Protection Act (CEPA) by Environment Canada. The DSL defines "existing" substances for the purposes of implementingCEPA and is the sole basis for determining whether a substance is "existing" or "new" to Canada. Substances that are not on the DSL may require notification and assessment before they can be manufactured or imported into Canada.
DOT stands for the U.S. Department of Transportation.
See Domestic Substances List.
An embryo is an organism in the early stages of its development prior to birth. In humans, the embryo is the developing child from conception to the end of the second month of pregnancy. (See also Fetus/Foetus.)
Embryotoxic means harmful to the embryo. Embryotoxicity is the ability of a substance to cause harm to the embryo. The Canadian Controlled Products Regulations describe technical criteria for identifying materials which have teratogenicity and embryotoxicity. They are part of the national Workplace Hazardous Materials Information System (WHMIS). (See also Fetotoxicity and Reproductive Effects.) Under the U.S. OSHA HAZCOM standard, embryotoxic effects are included as Target Organ Effects.
Engineering controls help reduce exposure to potential hazards either by isolating the hazard or by removing it from the work environment. Engineering controls include mechanical ventilation and process enclosure. They are important because they are built into the work process.
Engineering controls are usually preferred to other control measures such as the use of personal protective equipment. Substitution of a less hazardous material or industrial process is the best way to reduce a hazard and is often considered to be a type of engineering control.
The environmental fate of a chemical is a statement of what tends to happen to the chemical when it is released into the environment. Fate depends on properties of the chemical such as solubility, vapour pressure, partition coefficient, stability and reactivity. A chemical may preferentially end up in air, in water, or in soil, and may break down quickly or slowly.
EPA stands for the U.S. Environmental Protection Agency.
EU stands for the European Union, formerly known as the EEC (European Economic Community) and the EC (European Community).
The evaporation rate is a measure of how quickly the material becomes a vapour at normal room temperature. Usually, the evaporation rate is given in comparison to certain chemicals, such as butyl acetate, which evaporate fairly quickly. For example, the rate might be given as "0.5 (butyl acetate=1)." This means that, under specific conditions, 0.5 grams of the material evaporates during the same time that 1 gram of butyl acetate evaporates. Often, the evaporation rate is given only as greater or less than 1, which means the material evaporates faster or slower than the comparison chemical.
In general, a hazardous material with a higher evaporation rate presents a greater hazard than a similar compound with a lower evaporation rate.
Explosion data is information on the explosive properties of a material. Quantitative explosion data is seldom available and is usually given in descriptive terms such as low, moderate or high. The following types of information can be used to describe the explosive hazard of a material:
- Sensitivity to mechanical impact. This information indicates whether or not the material will burn or explode on shock (for example, dropping a package) or friction (for example, scooping up spilled material).
- Sensitivity to static discharge. This information indicates how readily the material can be ignited by an electric spark.
Detailed information is available on the properties of commercial explosives. In Canada, the storage, transportation and handling of commercial explosives are strictly regulated under the Explosives Act and Transport of Dangerous Goods Act. Commercial explosives are not regulated by the Controlled Products Regulations [e.g.,: not part of the Workplace Hazardous Materials Information System (WHMIS)].
Under the U.S. OSHA HAZCOM standard, a chemical is identified as explosive if it causes a sudden, almost instantaneous release of pressure, gas and heat when subjected to sudden shock, pressure or high temperature.
Explosive limits specify the concentration range of a material in air which will burn or explode in the presence of an ignition source (spark or flame). Explosive limits may also be called flammable limits or explosion limits.
The lower explosive limit (LEL), or lower flammable limit (LFL), is the lowest concentration of gas or vapour which will burn or explode if ignited. The upper explosive limit (UEL), or upper flammable limit (UFL), is the highest concentration of gas or vapour which will burn or explode if ignited. From the LEL to the UEL, the mixture is explosive. Below the LEL, the mixture is too lean to burn. Above the UEL, the mixture is too rich to burn. However, concentrations above the UEL are still very dangerous because, if the concentration is lowered (for example, by introducing fresh air), it will enter the explosive range.
In reality, explosive limits for a material vary since they depend on many factors such as air temperature. Therefore, the values given on a Material Safety Data Sheet are approximate.
The explosive limits are usually given as the percent by volume of the material in the air. One percent by volume is 10,000 ppm. For example, gasoline has a LEL of 1.4% and a UEL of 7.6%. This means that gasoline vapours at concentrations of 1.4% to 7.6% (14,000 to 76,000 ppm) are flammable or explosive.
Exposure Limits (or Occupational Exposure Limits (OELs))
An exposure limit is the concentration of a chemical in the workplace air to which most people can be exposed without experiencing harmful effects. Exposure limits should not be taken as sharp dividing lines between safe and unsafe exposures. It is possible for a chemical to cause health effects, in some people, at concentrations lower than the exposure limit.
Exposure limits have different names and different meanings depending on who developed them and whether or not they are legal limits. For example, Threshold Limit Values (TLVs) are exposure guidelines developed by the American Conference of Governmental Industrial Hygienists (ACGIH). They have been adopted by many Canadian governments as their legal limits. Permissible Exposure Limits (PELs) are legal exposure limits in the U.S. Sometimes, a manufacturer will recommend an exposure limit for a material.
Exposure limits have not been set for many chemicals for many different reasons. For example, there may not be enough information available to set an exposure limit. Therefore, the absence of an exposure limit does not necessarily mean the material is not harmful.
There are three different types of exposure limits in common use:
1) Time-weighted average (TWA) exposure limit is the time-weighted average concentration of a chemical in air for a normal 8-hour work day and 40-hour work week to which nearly all workers may be exposed day after day without harmful effects. Time-weighted average means that the average concentration has been calculated using the duration of exposure to different concentrations of the chemical during a specific time period. In this way, higher and lower exposures are averaged over the day or week.
2) Short-term exposure limit (STEL) is the average concentration to which workers can be exposed for a short period (usually 15 minutes) without experiencing irritation, long-term or irreversible tissue damage, or reduced alertness. The number of times the concentration reaches the STEL and the amount of time between these occurrences can also be restricted.
3) Ceiling (C) exposure limit is the concentration which should not be exceeded at any time.
"SKIN" notation (SKIN) means that contact with the skin, eyes and moist tissues (for example, the mouth) can contribute to the overall exposure. The purpose of this notation is to suggest that measures be used to prevent absorption by these routes; for example, the use of protective gloves. If absorption occurs through the skin, then the airborne exposure limits are not relevant.
Extinguishing media are agents which can put out fires involving the material. Common extinguishing agents are water, carbon dioxide, dry chemical, "alcohol" foam, and halogenated gases (Halons). It is important to know which extinguishers can be used so they can be made available at the worksite. It is also important to know which agents cannot be used since an incorrect extinguisher may not work or may create a more hazardous situation. If several materials are involved in a fire, an extinguisher effective for all of the materials should be used.
FDA stands for the Food and Drug Administration (U.S.).
Fetotoxic means the substance is harmful to the fetus/foetus. Fetotoxicity describes the ability of a substance to harm the fetus. (See also Embryotoxicity, Teratogenicity and Reproductive Effects.)
Fetus / Foetus
A fetus is an organism in the later stages of development prior to birth. In humans, it is the unborn child from the end of the second month of pregnancy to birth. (See also Embryo.)
FIFRA stands for Federal Insecticide, Fungicide and Rodenticide Act (U.S.).
First aid is emergency care given immediately to an injured person. The purpose of first aid is to minimize injury and future disability. In serious cases, first aid may be necessary to keep the victim alive.
Flammable means able to ignite and burn readily. Flammability is the ability of a material to ignite and burn readily. (See also Combustible.) Under the Canadian Controlled Products Regulations [ part of Workplace Hazardous Materials Information System (WHMIS)] and the U.S. HAZCOM Standard, there are specific technical criteria for identifying flammable materials. (See Flammable Aerosol, Flammable Gas, Flammable Liquid, Flammable Solid and Reactive Flammable Material.)
There are closely related criteria for the classification of certain flammable materials under the Canadian Transportation of Dangerous Goods (TDG) Regulations and the U.S. Department of Transportation regulations. (See TDG Flammability Classification.) In Canada, local, provincial and national fire codes also classify and regulate the use of flammable materials in workplaces. (See also Combustible.)
Under the Canadian Controlled Products Regulations, a material is identified as a flammable aerosol if it is packaged in an aerosol container which can release a flammable material. A flammable aerosol is hazardous because it may form a torch (explosive ignition of the spray) or because a fire fuelled by the flammable aerosol may flash back.
The Canadian Controlled Products Regulations are part of the national Workplace Hazardous Materials Information System (WHMIS). The U.S. OSHA HAZCOM Standard has a specific definition. Refer to the regulations for detailed information.
Flammable And Combustible Material
Under the Canadian Controlled Products Regulations, a material may be classified as a flammable and combustible material if it meets specific criteria for a flammable gas, flammable liquid, combustible liquid, flammable solid, flammable aerosol or reactive flammable material.
The Canadian Controlled Products Regulations are part of the national Workplace Hazardous Materials Information System (WHMIS).
A flammable gas is a gas which can ignite readily and burn rapidly or explosively. Under the Canadian Controlled Products Regulations and under the US Hazard Communication Standard, there are certain technical criteria for the identification of materials as flammable gases for the purposes of each regulation. Flammable gases can be extremely hazardous in the workplace; for example:
- If the gas accumulates so that its lower explosive limit (LEL) is reached and if there is a source of ignition, an explosion may occur.
- If there is inadequate ventilation, flammable gases can travel a considerable distance to a source of ignition and flash back to the source of the gas.
The Canadian Controlled Products Regulations are part of the national Workplace Hazardous Materials Information System (WHMIS).
See Explosive Limits.
A flammable liquid gives off a vapour which can be readily ignited at normal working temperatures. Under the Canadian Controlled Products Regulations, a flammable liquid is a liquid with a flash point (using a closed cup test) below 37.8 degrees C (100 degrees F). The US Hazard Communication Standard uses a similar, but not identical, definition.
Flammable liquids can be extremely hazardous in the workplace; for example:
- If there is inadequate ventilation, vapours can travel considerable distances to a source of ignition and flash back to the flammable liquid.
- It may be difficult to extinguish a burning flammable liquid with water because water may not be able to cool the liquid below its flash point.
The Canadian Controlled Products Regulations are part of the national Workplace Hazardous Materials Information System (WHMIS).
A flammable solid is a material which can ignite readily and burn vigorously and persistently. There are certain technical criteria in the Canadian Controlled Products Regulations [part of the Workplace Hazardous Materials Information System (WHMIS)] and in the US OSHA Hazard Communication Standard for the identification of flammable solids for the purposes of each regulation. These criteria are based on ease of ignition and rate of burning. Flammable solids may be hazardous because heat from friction (for example, surfaces rubbing together) or heat from processing may cause a fire. Flammable solids in the form of a dust or powder may be particularly hazardous because they may explode if ignited.
Flash back occurs when a trail of flammable gas, vapour or aerosol is ignited by a distant spark, flame or other source of ignition. The flame then travels back along the trail of gas, vapour or aerosol to its source. A serious fire or explosion could result.
The flash point is the lowest temperature at which a liquid or solid gives off enough vapour to form a flammable air-vapour mixture near its surface. The lower the flash point, the greater the fire hazard. The flash point is an approximate value and should not be taken as a sharp dividing line between safe and hazardous conditions. The flash point is determined by a variety of test methods which give different results. Two types of methods are abbreviated as OC (open cup) and CC (closed cup).
FR stands for Federal Register (U.S.).
See Melting Point.
Fumes are very small, airborne, solid particles formed by the cooling of a hot vapour. For example, a hot zinc vapour may form when zinc-coated steel is welded. The vapour then condenses to form fine zinc fume as soon as it contacts the cool surrounding air. Fumes are smaller than dusts and are more easily breathed into the lungs.
A gas is a material without a specific shape or volume. Gases tend to occupy an entire space uniformly at normal room pressure and temperature. The terms vapour and fume are sometimes confused with gas.
As used in a Material Safety Data Sheet, general ventilation, also known as dilution ventilation, is the removal of contaminated air from the general area and the bringing in of clean air. This dilutes the amount of contaminant in the work environment. General ventilation is usually suggested for non-hazardous materials. (See also Mechanical Ventilation, Local Exhaust Ventilation and Ventilation.)
GHS stands for the Globally Harmonized System of Classification and Labelling of Chemicals. It is intended that GHS be adopted worldwide. GHS addresses the classification of chemicals by types of hazard (health, fire, reactivity, environmental) and proposes harmonized hazard communication elements (labels and safety data sheets).
GI stands for gastrointestinal (relating to the stomach and intestines).
Although every effort is made to ensure the accuracy, currency and completeness of the information, CCOHS does not guarantee, warrant, represent or undertake that the information provided is correct, accurate or current. CCOHS is not liable for any loss, claim, or demand arising directly or indirectly from any use or reliance upon the information.