Common Words and Abbreviations Found on a Safety Data Sheet (SDS)

Acute Effect - An immediate result usually of short duration caused by exposure to a chemical.  For example, dizziness from exposure to solvent vapors or coughing and throat irritation from exposure to ammonia. 

ACGIH - American Conference of Governmental Industrial Hygienists.  An organization of professional personnel in government agencies or educational institutions engaged in occupational safety and health programs.  ACGIH develops and publishes recommended occupational exposure limits for hundreds of chemical substances and physical agents.

Allergen - Any substance which causes the body to produce antibodies when it contacts the skin or is inhaled or ingested.

Anesthetizer - A chemical which causes loss of feeling in all or part of the body. 

Asphyxiate - A gas which can bring about unconsciousness or death by depriving the body of oxygen.  Examples include carbon dioxide, nitrogen, helium and methane.

Autoignition Point - The minimum temperature required to initiate or sustain combustion in a chemical absent flame or spark.

Boiling Point - The temperature at which a liquid changes to a vapor state (usually expressed in degrees Fahrenheit at sea level pressure - 760 mmHg).  For mixtures, the initial boiling point or a boiling range may be given.  Flammable materials with low boiling points generally present special fire hazards.

Cardiotoxin - A chemical harmful to the heart.

CAS Number - Chemical Abstract Number.  A unique number assigned to a chemical to identify it.

Caution - A key warning word used on labels meant to signify a product that may cause minor injury or irritation if improperly handled.  The lowest level of warning of the three warning words “Danger, Warning, and Caution.”

Ceiling or “C” - The maximum allowable human exposure limit for an airborne substance not to be exceeded even momentarily.

Carcinogen - A substance capable of causing or producing cancer in humans and animals.

Chronic Effect - A delayed result usually of long-lasting or recurring duration caused by exposure to a chemical. 

Combustible - A liquid with a flash point between 100° and 200° Fahrenheit.

Concentration - The amount of a substance in a mixture or solution or in air.  Common methods of stating concentration are percent by weight or volume, parts per million, or milligrams per cubic meter. 

Corrosive - A liquid or solid that causes visible destruction or irreversible damage in human skin at the site of contact.

Danger - A key warning word used on labels meant to signify a product that may cause death if improperly handled.  The highest level of warning of the three warning words, “Danger, Warning, and Caution.”

Dermatitis - An inflammation of the skin.

Dose-Response - Refers to the amount of substance (dose) that will cause an effect (response).  Typically the greater the dose, the greater the effect.

Edema - An abnormal accumulation of fluid in cells, tissue, or cavities of the body.  When chemically induced, it is usually caused by chemicals that strongly irritate the tissue.  The edema results from the body trying to “cushion” the damage, not unlike the formation of a blister from a burn.

Evaporation Rate - The rate at which a particular material will evaporate when compared to the known rate of another material.

Explosive - A chemical that causes an almost instantanious release of gas and heat when subjected to certain conditions.

Hazardous Material - Any substance damaging to the health and well being of a person.

Flash Point - The temperature at which a liquid will give off enough flammable vapor to ignite.

Flammable Liquid - A liquid with a flash point below 100° Fahrenheit.

Hepatoxin - A chemical harmful to the liver.

IARC - International Agency for Research on Cancer.  IARC publishes a reference used by OSHA to classify a chemical as a carcinogen.

IDLH - Immediately Dangerous to Life and Health.  Usually refers to a concentration of a chemical in ppm’s, mg/m³, or percents.

Irritant - A chemical which is not corrosive, that can cause local skin inflammation on immediate, prolonged, or repeated contact with normal skin, eyes, or mucous membranes.

LEL - Lower Explosive Limit.  The lowest concentration of a chemical that will burn or explode if an ignition source is present.  Usually given in percents.

Mg/m³ - Milligrams per cubic meter.  A unit for measuring concentrations of dusts, gases, or mists in air.

Mutagen - A chemical which can alter genetic material in a living cell and cause physical or functional changes in future generations.

Nephrotoxin - A chemical harmful to the kidneys.

Neurotoxin - A chemical harmful to the brain and nervous system.

NFPA - National Fire Protection Association.  An organization which has developed a label for warning about fire and explosion hazards using a diamond divided into four sections.  The blue section represents health hazards.  The red section represents flammability hazards.  The yellow section represents a reactivity hazard.  The white section represents specific hazards, such as water reactive.

NIOSH - National Institute for Occupational Safety and Health, US Department of Health and Human Services.

Odor Threshold - The concentration of a chemical at which most people can smell it.  Some chemicals have odor thresholds that are above their permissible exposure levels (PELs), so that you will be over-exposed before you can smell the chemical.

Oxidizer - A chemical other than an explosive or blasting agent that initiates or promotes combustion in other materials by releasing oxygen or other gases.

PAPR - Powered Air Purifying Respirator.  A kind of respirator that uses a battery powered blower to draw air through a cartridge to purify it.  The blower places the air breathed by the respirator wearer under positive pressure, reducing leakage of the mask and making breathing easier.

PEL - Permissible Exposure Level.  An exposure limit established by OSHA.  Usually a TWA expressed in ppm or mgm³.

pH - A value presenting the acidity or alkalinity of an aqueous solution.

ACIDIC (1)       NEUTRAL (7)       Alkaline (14)

PPE - Personal Protective Equipment.  The last resort, after engineering and administrative controls, of reducing exposure to a chemical.  Includes respirators, gloves, ear plugs, etc.

PPM - Parts Per Million.  A unit for measuring concentrations of vapors or gases in air.

Pulmonary Edema - An abnormal accumulation of fluid in the lungs.  The fluid impairs the ability of the lungs to exchange oxygen and carbon dioxide with blood. 

Pyrophoric - A substance that burns spontaneously in air at a temperature of 130°F or below.

Reactive - A chemical that may polymerize, decompose, or condense under conditions of shock, pressure or temperature releasing large amounts of energy.

Reactives include:

• Explosive Materials
• Organic Peroxides
• Pressure-generating materials
• Water-reactive materials

REL - Recommended Exposure Limit.  An exposure limit for chemicals recommended by the National Institute for Occupational Safety and Health (NIOSH).  The exposure limit is usually more protective than the OSHA PEL or the ACGIH TLV, but is not enforceable.

Routes of Entry - Refers to the methods by which chemicals can enter the body.  Inhalation, skin absorption, and ingestion are the three most common routes.

Sensitizer - A chemical that causes an allergic or photodynamic reaction in normal tissue.

Specific Gravity - The weight of a chemical in relation to the weight of an equal volume of water (water=1).  If the specific gravity of the chemical is greater than 1, the chemical is heavier than water and sinks.  If the specific gravity of the chemical is less than 1, the chemical is lighter than water and will float.

STEL - Short Term Exposure Level.  The maximum concentration to which workers can be exposed for a period of up to 15 minutes continuously without irritation or harm, provided that the daily TWA is not exceeded.

Systemic - Usually used to refer to the effects of chemicals on the systems of the body or the organs.  For example, the circulatory system, nervous system, endocrine system or the heart, liver, lungs, kidneys, or brain.

Teratogen - A chemical which causes physical defects in the developing embryo.

TLV - Threshold Limit Value.  A term used by ACGIH to identify the airborne concentration of a material to which most persons can be exposed day after day without adverse effects.

TWA - Time Weighted Average.  An exposure concentration averaged over an eight hour day.  Used by OSHA and ACGIH.  Most PELs and TLVs are Time Weighted Averages.

UEL - Upper Explosive Level.  The highest concentration of a chemical which will burn or explode if an ignition source is present.  Usually given in percents.

Vapor Density - The relative weight of a chemical’s vapor to the weight of an equal volume of air (air=1).  If the vapor density is greater than 1, the vapor is heavier than air and sinks.  If the vapor density is less than 1, the vapor is lighter than air and rises.

Vapor Pressure - The pressure a liquid’s vapor exerts on air.  The higher the vapor pressure the more easily it will evaporate.  Vapor pressure is expressed in mm of mercury (mmHg); mmHg is equivalent to 14.7 pounds per square inch, the pressure of air at sea level.

Warning - A key warning word used on labels meant to signify a product that may cause permanent harm if improperly handled.  The middle level of warning of the three words, “Danger, Warning, and Caution.”