Hazard Communication Glossary
 

Acute Effect An adverse effect on a human or animal body with severe symptoms which develop rapidly wan will subside after the exposure stops.
Anesthetic A Chemical that causes a total or partial loss of sensation.  Overexposure can cause impaired judgment, dizziness, headache, drowsiness and even death.
Asphyxiant A chemical (vapor or gas) that can cause death or unconsciousness by suffocation.
Boiling Point The temperature at which a liquid changes to a vapor state.
"C" or Ceiling The maximum allowable exposure limit for an airborne substance.  This limit is not to be exceeded even momentarily.
Carcinogen A substance or agent that can cause a growth of abnormal tissue or tumors in humans or animals.
Chronic Effect An adverse effect on a human or animal body that can take months or years to develop after exposure.
Combustible Liquid Those liquids having a false point at or above 100°F.
Compressed Gas Any gas or mixture of gases having, in a container, an absolute pressure exceeding 40 psi at 70°F (21.1°C); or a gas or mixture of gases having, in a container, an absolute pressure exceeding 104 psi at 130°F (54.4°C) regardless of the pressure at 70°F (21.1°C); or a liquid having a vapor pressure exceeding 40 psi at 100°F (37.8°C) as determined by ASTM D-323-82.
Corrosive According to DOT, causes visible destruction or permanent changes in human skin tissue at the site of contact or is highly corrosive to steel.
Decomposition Breakdown of a material or substance (by heat, chemical reaction, decay or other processes) into parts or simpler compounds.
Density The mass (weight) per unit volume of a substance.
DOT Hazard Class A Department of Transportation labeling system used for hazardous material that are being transported.  These classes include corrosive, flammable liquid, organic peroxide poison, etc.
Evaporation Rate The rate at which a material is converted to vapor (evaporates) at a given temperature and pressure when compared to the evaporation rate of a given substance.
Explosive A chemical that causes a sudden almost instantaneous release of pressure gas and heat when subjected to sudden shock, pressure or high temperature.
 
Flammable Liquid Those liquids having a flash point below 100°F.
Flammable Gas A gas that, at ambient temperature and pressure, forms a flammable mixture with air at a concentration of thirteen percent (13%) by volume or less; or a gas that at ambient temperature and pressure, forms a range of flammable mixtures with air, wider than twelve percent (12%) by volume, regardless of the lower limit.
Flammable Solid A solid other than a blasting agent or explosive as defined in 29CFR 1910.109 (a), that is liable to cause fire through friction, absorption or moisture, spontaneous chemical change, or retained heat from manufacturing processing, or which can be ignited readily and when ignited burns so vigorously and persistently as to create a serious hazard.
Flash Point The temperature at which a liquid will give off enough flammable vapor to ignite if an ignition source is present.  There are several flash point test method, and flash points may vary for the same material depending on the method used, so the test method is indicated when  the flash point is given.
General Exhaust A system for exhausting air containing contaminants from a work area, usually accomplished by dilution.
Hazardous Chemical  Any chemical which is a physical hazard or a health hazard.
Hazard Warning Any words, pictures symbols, or combination thereof appearing on label of other appropriate form or warning which convey the hazard of the chemical(s) in the container(s).
Hazardous Decomposition Products Any hazardous material that may-be produced in dangerous amounts of the material reacts with other agents, burns, or is exposed to other processes such as welding.
Hazardous Polymerization Polymerization is a chemical reaction in which one or more small molecules combine to form larger molecules.  The reaction occurs at a rate which realize large amounts of energy.
Health Hazard A chemical for which there is statistically significant evidence based on at least one scientific study that acute or chronic health effects may occur in exposed employees.
Ignition Source A material or energy source that will cause, create, or initiate the minimum temperature at which a substance will continue to burn without the application of external heat.
Immediate Use Means that the hazardous chemical will be under the control of and used only by the person who transfers it from a labeled container only within the work shift in which it is transferred.
Incompatible The term applied to two substances to indicate that one material cannot be mixed with the other without the possibility of a dangerous reaction.
Ingestion The taking in of a substance through the mouth.
Inhalation The breathing in of a substance in the form of a gas, vapor, or particulate.
Insoluble Incapable of being dissolved in a liquid.
Irritant A substance that produces an irritating effect when it contacts skin, eyes, nose or respiratory system.

 
Lethal     Concentration50 (LC50) The concentration of an air contaminant that will kill 50 percent of the test animals in a group during a single exposure.
Lethal Dose50 (LC50) The dose of a substance or chemical that will kill 50 percent of the test animals in a group within the first 30 days following exposure.
Local Exhaust Ventilation A ventilation system that removes contaminants from the air at the point where contaminants are generated.
Lower Explosive Limit (Also known as Lower Flammable Limit.)  The lowest concentration of a substance that will produce a fire or flash when an ignition source is present.
Melting Point The temperature at which a solid changes to a liquid.
Mechanical Exhaust A mechanical device, like a motor-driven fan, that removes contaminants  from a work area.
Mutagen Anything that can alter the genetics make-up of a sperm or egg cell.
Oxidizer A substance that gives up oxygen  easily to stimulate combustion of organic material.
Permissible Exposure Limit (PEL) An exposure limit that is published and enforced by OSHA as a legal standard.
Personal Protective Equipment Any devices or clothing worn by the worker to protect against hazards in the environment.
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 oxidizer, pyrophoric, unstable (reactive) or water-reactive.
Pyrophoric A chemical that is capable of self-ignition when it is exposed to air.
Reactivity A substance’s susceptibility to undergo a chemical reaction or change that may result in dangerous side effects.
Respiratory Protection Consists of air cleaning or air supplying devices that protect your breathing system from contaminants or supply fresh air in toxic/oxygen deficient atmospheres.
Routes of Entry The means by which material may gain access to the body, for example, inhalation, ingestion and skin contact.
Sensitizer A substance that may cause no reaction in a person during initial exposures, but afterwards, further exposures will cause an allergic response to the substance.
Skin Absorption The ability of some hazardous chemicals to pass directly thorough the skin and enter the bloodstream.
Solubility in Water Indicates how much of a substance will dissolve in water.
Specific Gravity The weight of a material compared to the weight of an equal volume of water, and expression of the density of the material.
Target Organ Toxin A toxic substance that attacks a specific organ of the body.
Teratogen A substance that can cause birth defects in the fetus of a pregnant female.
Threshold Limit Value (TLV) Threshold Limit Value; a term used by ACGIH to express the airborne concentration of a material to which nearly all persons can be exposed day after day, without adverse effects.
Time Weighted Average (TWA) The average time, over a given work period (e.g., 8 hour workday) of a person’s exposure to a chemical or an agent.
Toxicity The sum of adverse effects resulting from exposure to a material.
Upper Explosive Limit (UEL) (Also know as Upper Flammable Limit.)  It is the highest concentration of a substance that will burn or explode when an ignition source is present.
UN Number A number required  in shipping documentation and on packaging as a part of the DOT regulations for shipping hazardous materials.
Vapor Density The weight of a vapor or gas compared to the weight of an equal volume of air; an expression of the density of the vapor or gas.