Wisconsin's Public Liberal Arts College

Material Safety Data Sheet Glossary


Environmental Health and Safety

Material Safety Data Sheet Glossary


A - B - C - D - E - F - G - H - I - J - K - L - M
N - O - P - Q - R - S - T - U - V - W - X - Y - Z

A

AAOHN - American Association of Occupational Health Nurses

ABIH - American Board of Industrial Hygiene

ABSORPTION - The uptake of fluids or other substances by the body.

ACGIH - American Conference of Governmental Industrial Hygienists. One of the important activities conducted by the ACGIH is the research of the health effects of exposure to toxic substances and physical agents to establish Threshold Limit Values.

ACID - A compound consisting of hydrogen plus one or more other elements which readily releases hydrogen when mixed with water or some solvents. Acids have pH values between 0 - 7. When an acid reacts with a base (alkali), a salt is formed. Acids act as corrosives, unless highly diluted.

ACRID A harsh, irritating odor or taste.

ACS - American Chemical Society

ACTION LEVEL (AL) - The concentration of contaminants in air at which certain regulations established by OSHA must be implemented to protect the employee. Action levels exist for only a few air contaminants, such as lead, cadmium and benzene. At air concentrations above the action level, the employer must implement certain requirements of the regulation, such as medical monitoring and training, to further protect the employee.

ACUTE TOXICITY - The adverse effects resulting from a short duration, excessive exposure to a substance.

ACUTE EFFECT - An effect with a rapid onset after a short period of exposure.

AEROSOL - A fine suspension of liquid or dust particles in air that can remain suspended in air for a period of time. Aerosols have particle diameters of 0.01 to 100 micrometers.

AESTHESIA - Loss of sensation or feeling.

AIHA - American Industrial Hygiene Association

AL - See Action Level

ALIPHATIC - A carbon-based organic compound derived from a paraffin base, often petroleum, that has a straight or branched chain, and has a saturated or unsaturated molecular structure. Examples: hexane, naphtha, mineral spirits.

ALKALI - A basic compound with a pH between 7 - 14. Alkalis or bases are capable of neutralizing an acid and form a salt. Alkalis act as corrosives, unless highly diluted.

ALOPECIA - Loss of hair.

AMA - American Medical Association

AMBIENT - Typical surrounding conditions.

ANALGESIA - Loss of sensitivity to pain.

ANAPHYLAXIS - A severe, life-threatening allergic-type reaction to a substance resulting from sensitization to the substance. Prior contact with the substance is necessary.

ANEMIA - A reduction in red blood cells or hemoglobin.

ANHYDRIDE - An oxide or compound which produces an acid or base when combined with water.

ANHYDROUS - Does not contain water.

ANOMALY - A malformation.

ANOREXIA - Loss of appetite.

ANOSMIA - Loss of sense of smell.

ANOXIA - Lack of oxygen from inspired air.

ANSI - American National Standards Institute

ANTAGONISTIC EFFECT - The resulting effect of two or more substances that is less than the expected effect of either substance.

APNEA - Normal breathing is momentarily interrupted or stops.

AQUEOUS - Water-based solution.

ARGYRIA - Local or generalized impregnation of the body tissues with silver giving the skin a blue-gray color.

AROMATIC - Fragrant or a marked odor. A group of hydrocarbons and their derivatives characterized by the presence of one or more six-carbon rings. Examples are: toluene, benzene, xylene.

ASPHYXIA - Suffocation or unconsciousness as a result of poor oxygenation of the blood.

ASPHYXIATION - A condition that causes asphyxia, suffocation.

ASTHMA - A disease characterized by recurring attacks of difficulty breathing, wheezing and cough, due to spasmodic contractions of the bronchioles.

ASTM - American Society of Testing and Materials

ATAXIA - Loss of muscular coordination due to nervous system disorders.

ATM - See Atmosphere

ATMOSPHERE - A measurement of air pressure. The pressure exerted by air at sea level that will support a column of mercury 760 mm high. One atm equals 14.7 lbs/square inch.

ATROPHY - A wasting or shrinking in the size of a part of the body.

AUTO-IGNITION TEMPERATURE - The lowest temperature at which a flammable gas- or vapor-air mixture will ignite from its own heat source or a contacted heated surface without the presence of a spark or flame.

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B

BARRIER CREAM - A cream for use on the skin to protect against injury from contact with specific types of harmful substances.

BASE - An alkali; a compound with a pH value between 7.0 and 14. Bases react with acids to form a salt. Usually acts as a corrosive, unless it is highly diluted.

BIOHAZARD - A combination of the words "biological hazard" and is used to describe infectious agents presenting a risk or potential risk to the well-being of man or animals, either directly through infection or indirectly through disruption of the environment.

BIOLOGICAL HALF-LIFE - The time required for a given species, organ, or tissue to eliminate half of a substance which it takes in.

BLS - Bureau of Labor Statistics

BODY BURDEN - The total amount of toxic material that has entered a body through inhalation, ingestion, absorption through the skin or injection over time. Body burdens are often expressed as mg/kg of body weight.

BOILING POINT - The temperature at which a substance will boil. The point at which the vapor pressure of a liquid is equal to atmospheric pressure.

BP - See Boiling Point

BRADYCARDIA - A slow heartbeat in which the pulse rate falls below 60.

BREATHING ZONE - The area of the ambient environment in which a person breathes. Usually considered to be within 2 feet of the person's head.

BRONCHITIS - Inflammation of the bronchial tubes.

BUFFER - A substance that reduces the change in pH which otherwise would result from adding acids or bases.

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C

°C - Temperature in degrees Celsius or centigrade.

ca - (circa) about

CARCINOGEN - Cancer-causing chemical.

CARCINOGENIC - Cancer-producing.

CARCINOMA - A form of cancer.

CARDIOVASCULAR SYSTEM - The heart and circulatory system. The effects caused by toxic substances on the cardiovascular system can include irregular heart beats or cardiomyopathy.

CAS - See Chemical Abstract Service Registry Number

CASRN - See Chemical Abstract Service Registry Number

CATALYST - A substance which causes a chemical reaction to proceed faster without being consumed by the reaction.

CATARACT - A loss of transparency of the lens of the eye or of its capsule.

CAUSTIC - A substance which strongly irritates, burns or destroys tissues, usually refers to an alkali or base.

cc - cubic centimeter

CC - Closed Cup, a specific method used for determining the flashpoint of a volatile substance.

CEILING LIMIT (C) - The maximum air contaminant concentration an employee may be exposed to during any time during a work period.

CELSIUS (°C) - A temperature scale in which 0 øC is the freezing point of water (32 øF), and 100 øC is the boiling point of water (212 °F). Celsius and centigrade are the same temperature scale.

CENTIGRADE - See Celsius.

CENTRAL NERVOUS SYSTEM (CNS) - The central nervous system includes the sensory and motor nerves, spinal column and brain. The effects caused by toxic substances on the CNS include headaches, tremors, dizziness, narcosis, irritability, memory loss, difficulties in concentrating, sleep disturbances, nervousness, and fatigue.

CFM - Cubic Feet Per Minute

CFR - Code of Federal Regulations. Rules established by the Federal Government are incorporated into a written code.

CHEMICAL ABSTRACT SERVICE REGISTRY NUMBER (CAS OR CASRN) - A unique number assigned to identify a specific chemical or material.

CHEMICAL HYGIENE OFFICER - The appointed individual(s) responsible for administering the chemical hygiene plan.

CHEMICAL HYGIENE PLAN - A detailed written plan designed to protect employees from chemical and physical hazards in the laboratories.

CHLORACNE - An acne-like eruption from contact with substances containing chlorine.

CHO - See Chemical Hygiene Officer.

CHP - See Chemical Hygiene Plan.

CHROMOSOME - A structure in all cells that contain the genes (genetic material).

CHRONIC TOXICITY - An adverse effect on a human or animal with symptoms that develop slowly over an extended period of time or that recur frequently.

CHRONIC EFFECT - An adverse effect on a human or animal with symptoms that develop slowly over an extended period of time or that recur frequently.

CHRONIC - Persistent, prolonged, and/or repeated effects which are the result of repeated exposure to low concentrations of a chemical substance over a long period of time.

CNS - see Central Nervous System

COMBUSTIBLE LIQUID - Any liquid with a flash point above 100 degrees F.

COMBUSTIBLE - A substance with a flash point of 100 øF (38 øC) or higher. Also see the description of Flammable.

CONC -See concentration

CONCENTRATION - The amount of a substance in a given amount of air or water.

CONJUNCTIVITIS - Inflammation of the conjunctiva, the delicate membrane that lines the eyelids and covers most of the eyeball.

CONTACT DERMATITIS - A skin disease or condition caused by contact with an irritant.

CORNEA - The transparent structure of the external layer of the eyeball.

CORROSIVE - Any material that causes visible destruction of, or irreversible alterations in, animal or human skin tissues at the site of contact.

CUBIC METER (M3) - A unit of volume in the metric system. One cubic meter is equal to 1000 liters or 35.3 cubic feet.

CUTANEOUS HAZARDS - Chemicals that irritate or otherwise damage the skin.

CVA - See Cardio Vascular System.

CYANOSIS - Blueness of the skin, generally caused by lack of oxygen.

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D

DEBILITATING - Causing weakness.

DECOMP - decomposition

DECOMPOSITION - Breakdown.

DEPARTMENT OF COMMERCE - Safety Division. The Wisconsin state agency responsible for the health and safety of public sector employees.

DERMAL - Used on or applied to the skin.

DERMAL TOXICITY - Adverse effects on the skin.

DERMATITIS - Inflammation of the skin. There are two types of skin reactions: primary irritation from an irritant or corrosive and sensitization dermatitis from a sensitizer.

DEVELOPMENTAL TOXIN - See REPRODUCTIVE TOXIN.

DHHS - U.S. Department of Health and Human Services

DILHR - Department of Industry, Labor and Human Relations. The former regulatory body in the State of Wisconsin for health and safety for public employees. This is now a function of the Department of Commerce-Safety Division.

DOL - U.S. Department of Labor, of which OSHA is a part.

DOSE - The term used to express the amount of a substance absorbed in a unit volume of an organ or individual.

DOT - U.S. Department of Transportation

DYSFUNCTION - Any abnormality or impairment of an organ.

DYSPNEA - Labored or difficult breathing.

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E

ECZEMA - A skin disease; one specific type of dermatitis.

EDEMA - An abnormal accumulation of clear, watery fluid in the tissues; swelling.

EFFUSION - The escape of fluid into a part.

ELEMENT - A substance composed entirely of one kind of atom.

EMBRYO - The early stage of development of an organism. In humans, the embryo stage lasts from conception through the eighth week after conception.

EMBRYOTOXIC - See REPRODUCTIVE TOXIN

EMPHYSEMA - A lung disease in which the presence of air in the connective tissues of the lungs causes swelling or inflammation. The walls of the air sacs (alveoli) have been damaged beyond repair making the intake of oxygen into the blood and the release of carbon dioxide from the blood difficult.

EPA - Environmental Protection Agency

EPISTAXIS - Nosebleed.

ERYTHROCYTES - Red blood cells.

EVAPORATION RATE - The time required for a given amount of material to completely vaporize (evaporate) when compared to an equal amount of a reference material.

EXPLOSIVE LIMITS - Those concentrations of a vapor in air below or above which a flame or explosion does not occur on contact with a source of ignition. See also UEL and LEL.

EXPOSURE LIMIT - The time weighted average air contaminant concentration most workers may be exposed to for an 8 hour day, 40 hour work week without suffering adverse health effects.

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F-G-H

FIBROSIS - Formation of scar tissue.

FLAMMABLE (EXPLOSIVE) LIMITS - Those concentrations of a vapor in air below or above which a flame or explosion does not occur on contact with a source of ignition. See also UEL and LEL.

FLAMMABLE - Any substance that is easily ignited, burns intensely, or has a rapid rate of flame spread. A substance with a flashpoint below 100 øF is considered flammable. See COMBUSTIBLE.

FLASH POINT - The lowest temperature at which a liquid produces enough vapor to form an ignitable mixture with the air.

FR - Federal Register

FUME - Finely divided particles created when volatilized solids condense in cool air, such as a heated process like welding. (Fumes are technically not vapors or gases.) Fumes have particle sizes of one micrometer or less.

FUME FEVER - An acute condition caused by a brief high exposure to the freshly generated fumes of metals.

G, g or gm - gram. A metric unit of weight or mass. One ounce equals 28.4 grams. The following conversion units may be useful:

1000 Grams = 1 Kilogram
1000 milligrams (mg) = 1 Gram
1,000,000 micrograms (ug) = 1 Gram


GANGRENE - Death of tissue combined with putrefaction.

GAS - Substances that are not solid or liquid at normal temperatures and pressure.

GASTROENTERITIS - Inflammation of the stomach and intestines.

GENERAL (DILUTION) VENTILATION - A ventilation system consisting of mechanical air movement to mix with and dilute the contaminants in the space and exhaust them to the outside. NOTE: this is not the type of ventilation that is designed to maintain normal ventilation and thermal comfort in a space. General ventilation is not designed to control highly toxic materials or large quantities of air contaminants.

GI - Gastrointestinal

HEMATOLOGIC - Pertaining to the blood.

HEMATOPOIETIC SYSTEM - The blood forming tissues of the body, such as the bone marrow.

HEMATURIA - The presence of blood in the urine.

HEPA FILTER - High Efficiency Particulate Air Filter. A filter material that removes 99.97% or more of particles of 0.3 micrometer or larger. Used in applications where toxic dusts must be carefully controlled.

HEPATIC SYSTEM - Relating to the liver.

HEPATOTOXIN - Substances which produce liver damage.

HYDROCARBON - A substance composed of carbon and hydrogen.

HYDROPHOBIC - Repelled or repulsed by water.

HYGROSCOPIC - Readily absorbs or retains moisture.

HYPER- (prefix) - Over, above, increased.

HYPERPLASIA - Excessive formation of tissue.

HYPO- (prefix) - Under, less, decreased.

HYPOXIA - Insufficient oxygen.

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I

IARC - International Agency For Research on Cancer

IDLH - See Immediately Dangerous to Life and Health

IGNITABLE - The ability to be ignited, a substance having a flash point of 140 øF or less.

IMMEDIATELY DANGEROUS TO LIFE AND HEALTH (IDLH) - The concentration of an air contaminant that would cause an immediate threat of loss of life, severe injuries or irreversible adverse health effects during escape from the hazardous atmosphere.

IMMISCIBLE -Liquids which will not mix with each other, but will form two separate layers or will result in cloudiness.

INCOMPATIBLE - Materials that could cause dangerous reactions as a result of direct contact with one another.

INERT - The substance is so stable, it will not react with other materials.

INFLAMMATION - A tissue reaction to infection or trauma produced by an injury, irritant, corrosive or other chemical or physical agent. An inflammation is characterized by redness, heat and swelling.

INGESTION - The taking in of a substance by mouth.

INHALATION - The act of breathing in, the most common route of entry for chemicals.

INHIBITOR - An agent which arrests or slows a chemical reaction.

INJECTION - The entry of chemicals into the body by means of penetrating the skin.

INORGANIC - Compounds that do not contain carbon.

INSOLUBLE - A substance that is incapable of being dissolved.

INTER- (prefix) - Between.

INTOXICATION - Drunkenness or poisoning.

INTRA- (prefix) - Within.

IRRITANT - A substance that causes an irritating reversible effect on the skin, eyes and mucous membranes.

ISCHEMIA - Loss of blood supply to a portion of the body.

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J-K-L

KETOSIS - Elevated levels of "ketone bodies" in the body tissues.

kg or Kg - kilogram. See the definition under G, grams.

L - See Liter.

LACRIMATION - An excessive production of tears.

LATENT PERIOD - The time between exposure and the first indication of damage.

LAVAGE - The washing of a hollow organ, such as the stomach.

LC or LC50- See Lethal Concentration

LD or LD50 - See Lethal Dose

LEL - See Lower explosive limit.

LESION - Injury, damage or abnormal change to body tissue or organs.

LETHAL DOSE 50 - LD50 - The amount of a substance that will kill 50% of the test animals in a population.

LETHAL DOSE (LD) - The amount of a substance that will kill a test animal.

LETHAL CONCENTRATION (LC) - The concentration of a substance that is sufficient to kill a test animal.

LETHAL CONCENTRATION 50 - LC50 - The concentration of a substance that will kill 50% of the test animals in a population.

LEUKEMIA - Cancer of the blood.

LEUKOCYTES - White blood cells.

LITER - A measure of volume in the metric system. One liter equals 1.056 quarts.The following conversion units may be useful:

1 Liter = 1000 Grams
1 Liter = 1000 Milliliters
1 Milliliter = 1 Cubic Centimeter (cc)
1 Liters = 1,000,000 Microliters (ul)


LOCAL EXHAUST VENTILATION - A ventilation system designed to capture air contaminants at the point of generation. Local exhaust is required for moderate to highly toxic air contaminants.

LOWER EXPLOSIVE LIMIT (LEL) The lowest concentration (percentage) of a gas or vapor in air that will cause an explosion or support combustion with an ignition source.

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M

M - See Meter.


M3 or cu m - cubic meter

MALAISE - A feeling of general discomfort, distress or uneasiness.

MELTING POINT - The temperature at which a solid becomes a liquid.

METASTASIS - Transfer of a disease-producing body from the site of disease to another part of the body; a secondary growth of a malignant tumor.

METER - A unit of distance measurement in the metric system. One meter equals 39.37 inches. The following conversion units may be useful:

1000 Meters (M) = 1 Kilometer (Km)
100 centimeters (cm) = 1 Meter (M)
1000 millimeters (mm) = 1 Meter (M)
1,000,000 micrometers (ul) = 1 Meter (M)


mg/M3 - milligrams of substance per cubic meter of air

MG or mg or mG - milligrams. See discussion under G or grams.

MICRO (u ) (prefix) - one millionith of a unit.

MISCIBLE - Capable of being mixed.

MIST - Finely divided liquid droplets suspended in air.

MIXTURE - A combination of two or more substances which may be separated by mechanical means.

ml - milliliter. See the description under Liter

mm Hg - millimeters of mercury, a unit of atmospheric pressure.

MOLECULAR WEIGHT (MW) - The sum of the atomic weights of the constituents of a substance.

MP - See melting point.

mppcf - millions of particles per cubic feet of air

MSDS - Material Safety Data Sheet

MSHA - Mine Safety and Health Act.

MUTAGEN - A chemical which causes a defect in sperm or egg cells, prior to conception.

MW - See molecular weight

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N

NARCOSIS - Stupor or unconsciousness produced by some narcotic drug or chemical.

NAUSEA - Tendency to vomit, feeling of sickness of the stomach.

NECROSIS - Local death of tissue.

NEPHRITIS - Inflammation of the kidneys.

NEPHROTOXIN - A chemical which produces kidney disease.

NEURITIS - An inflammation of a nerve.

NEUROTOXIN - A chemical which affects the nervous system.

NFPA - National Fire Protection Association

NIOSH - National Institute of Occupational Safety and Health

NTP - National Toxicity Program of the EPA.

NYSTAGMUS - Spasmic, involuntary motion of the eyeballs.

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O

ODOR THRESHOLD - The lowest concentration that can be detected by the sense of smell.

ODOR - The property of a substance that gives it a smell.

OLFACTORY - Pertaining to the sense of smell.

OLIGURIA - Scanty or low volume of urine.

OPAQUE - Impervious to light rays.

ORAL TOXICITY - Adverse effects resulting from taking a substance into the body through the mouth.

ORAL - Through the mouth.

ORGANIC PEROXIDES - Organic compounds that are highly reactive; some are unstable and may act as an explosive or oxidizer especially upon standing or exposure to air.

ORGANIC - Chemicals that contain carbon.

OSHA - Occupational Safety and Health Administration

OXIDIZER - A chemical, other than a blasting agent, or an explosive, which contains oxygen and may start or assist combustion of other materials.

OXIDIZING AGENT - A material which gives off oxygen during a chemical reaction.

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P-Q-R

PCB - Polychlorinated Biphenyls

PEL - See Permissible Exposure Limit

PERFORATION - A hole.

PERICARDIAL - Concerning the membrane (pericardium) which surrounds the heart.

PERMISSIBLE EXPOSURE LIMIT - An exposure limit established by OSHA as a legal limit of employee exposure. The 8 hour time weighted average concentration most employee's may be exposed to without causing serious adverse effects.

pH - A measure of the level of acidity or alkalinity. Strong acids have a pH near 1, strong bases near 13, and a pH of 7 indicates neutrality.

PLEURAL - Concerns the membrane (pleura) which surrounds the lungs.

PNEUMONOCONIOSIS - Lung disease resulting from continued inhalation of dust.

POLYCYTHEMIA - Excess red blood cells.

POLYMERIZATION - A chemical reaction in which two or more small molecules form a larger different material accompanied by a release of energy.

PPB or ppb - parts of contaminant per billion parts of air or water.

PPE Personal protective equipment.

PPM or ppm - parts of contaminant per million parts of air or water.

PULMONARY EDEMA - Excessive fluid in the lungs.

PYROPHORIC - A type of chemical that will ignite spontaneously and burn when exposed to air temperatures below 130 degrees F.

REACTIVE - The ability to react vigorously, decompose or condense under conditions of shock, pressure or temperature.

REACTIVITY - The ability of a material to undergo chemical reaction with the release of energy or heat.

REDUCING AGENT - A material which accepts oxygen in a reaction.

REPRODUCTIVE TOXINS - Chemicals which have a negative effect on the ability to produce normal offspring.

RESPIRATORY - Pertaining to the ability to breathe and to exchange gases in the lungs.

ROE - See Route of entry.

ROUTE OF ENTRY (ROE) - The pathways a chemical or biological hazard may use to enter the body. Generally speaking, the most common ROEs are inhalation, ingestion, absorption, and injection.

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S

STEL - See Short Term Exposure Limit

SCBA - Self-contained breathing apparatus. A respirator.

SENSITIZER - A substance that can cause an allergic reaction of the skin or respiratory system.

SENSITIZATION - An allergic response that increases in severity with repeated exposure.

SHORT TERM EXPOSURE LIMIT (STEL) - The air contaminant concentration an employee may be exposed to for a 15 minute TWA without suffering from serious adverse health effects. STELs should occur no more than 4 times per day with 60 minutes between STELs.

SIDEROSIS - Lung condition resulting from inhalation of dust or fumes which contain iron.

SOLUBILITY IN WATER - The percentage of a material (by weight) that will dissolve in water at ambient temperature. Terms used to express solubility are:

Neglible Less than 0.1%
Slight 0.1 - 1.0%
Moderate 1 - 10%
Appreciable More than 10%
Complete Soluble in All Proportions


SOLUBLE - Capable of being dissolved.

SPASM - An involuntary, convulsive muscular contraction.

SPECIFIC GRAVITY - A measurement used to quantify the weight of a substance by comparing the weight of a given volume of material to the same volume of water. Material with a specific gravity of greater than 1 is heavier than water.

SPONTANEOUS COMBUSTION - Combustion resulting from chemical reaction with the slow generation of heat from oxidation of organic compounds until the ignition temperature of the material is reached.

STABILITY - The tendency of a material to resist chemical changes during storage or transportation.

STEL - See Short Term Exposure Limit.

STP - Standard Temperature and Pressure

STUPOR - Partial or nearly complete unconsciousness.

SYNERGISTIC - The effect of two or more substances is greater than the anticipated sum of the effects of the individual substances.

SYS - See systemic effects

SYSTEMIC - Spread throughout the body and affecting all body systems and organs; not localized to one area.

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T

TACHYCARDIA - Excessively rapid heartbeat.

TARGET ORGAN (TO) - Primary organ in the body affected by a chemical.

TCC - Tag Closed Cup - a measurement made to determine flash point.

TEMP - temperature

TERATOGENS - Chemicals that cause birth defects to occur in a developing embryo or fetus when a pregnant female is exposed to the chemical.

THERMAL DECOMPOSITION - The breakdown of a material, when heated.

THRESHOLD LIMIT VALUE (TLV or TLV-TWA) - The ACGIH-recommended time weighted average air contaminant concentration that most workers may be exposed to for an 8 hour day, 40 hour work week without suffering adverse health effects. TLV's may be expressed as: TLV-TWA, TLV-Ceiling, TLV-STEL. This is an advisory limit and not enforceable by law.

TIME WEIGHTED AVERAGE (TWA) - A weighted airborne concentration averaged over a time period, usually 8 hours.

TINNITUS - Ringing in the ears.

TLV or TLV-TWA - See Threshold Limit Value

TORR- a unit of air pressure. See atmosphere. One Torr equals 1 mm mercury.

TOXEMIA - Poisoning by way of the blood stream.

TOXICITY - The degree of injury or illness caused by a toxic material.

TRANSIENT - Not permanent.

TWA - See Time-Weighted Average

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U-V-W-X-Y-Z

u - see Micro (prefix) or Gram, Liter or Meter.

UEL - See Upper Explosive Limit

UNSTABLE - Reactive. The ability to react vigorously, decompose or condense under conditions of shock, pressure or temperature.

UPPER EXPLOSIVE LIMIT (UEL) - The highest concentration (percentage) in air that will support combustion or cause an explosion with an ignition source. See Flammable Explosive Limits.

URTICARIA - Itching skin rash.

VAPOR PRESSURE (VP) - A measure of how readily a material will evaporate. The lower the vapor pressure, the slower it evaporates.

VAPOR DENSITY - A measure of how heavy a vapor is compared to air, which has a vapor density of 1.

VAPORS - The gaseous form of substances that are normally solids or liquids at room temperature. (Vapors and gases are not fumes.)

VERTIGO - A feeling of revolving in space, dizziness.

VISCOSITY - Resistance to flow exhibited by a liquid.

VOLATILITY - The tendency or ability of a liquid to evaporate.

VP - See Vapor Pressure

WATER REACTIVE - A chemical that reacts vigorously with water.


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