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C:

Centigrade, a unit of temperature.

CALORIE:

Standard unit of heat. A calorie is the amount of heat required to raise 1 gram of water 1 degree C.

CARBON DIOXIDE:

(CO2) heavy, colorless gas produced by combustion and decomposition of organic substances and as by-product of chemical processes. Will not burn, relatively non-toxic, and unreactive. Can cause oxygen deficient environments in large concentrations. Is useful as fire-extinguishing agent to block oxygen and smother fire.

CARBON MONOXIDE:

CO) colorless, odorless, flammable, and very toxic gas produced by the incomplete combustion of carbon compounds and as a by-product of many chemical processes. A chemical asphyxiant, it reduces the blood's ability to carry oxygen.

CARCINOGEN:

Substance or agent capable of causing or producing cancer in mammals.

CARCINOMA:

Malignant tumor or cancer; a new growth made up of epithelial cells tending to grow rapidly, infiltrate other cells, and give rise to metastasis (spreading).

(CAS) CHEMICAL ABSTRACTS SERVICE NUMBER:

An assigned number used to identify a chemical. CAS stands for Chemical Abstracts Service, an organization that indexes information published in Chemical Abstracts by the American Chemical Society and that provides index guides by which information about particular substances may be located in the abstracts. Sequentially assigned CAS numbers identify specific chemicals, except when followed by an asterisk(*) which signifies a compound (often naturally occurring) of variable composition. the numbers have no chemical significance. The CAS number is a concise, unique means of material identification.

CATALYST:

Substance that modifies a chemical reaction (makes it faster or slower) without being consumed.

CATARACT:

Loss of transparency of the crystalline lens of the eye or its capsule.

CAUSTIC:

See Alkali.

CC:

Closed cup. Identifies one of the methods used to measure flash points of flammable liquids.

cc, cm3

Cubic centimeter.

CEILING:

Maximum allowable human exposure limit for airborne substances; not to be exceeded even momentarily.

CENTIPOISE:

cgs unit of the measure of viscosity equal to 1/100 poise. Viscosity of water at 20C is approximately 1 centipose.

CENTIMETER, cm:

1/100 meter. A cm = approximately 0.4 in.

CERCLA:

Comprehensive Environmental Response, Compensation, and Liability Act. The Superfund Law, Public Law PL 96-510, found at 40 CFR 300. The EPA has jurisdiction.

CFC:

Chlorofluorocarbon. Associated with damage to the Earth's ozone layer.

CFR:

Code of Federal Regulations. A collection of the regulations established by law.

cgs:

Metric units of measure based upon centimeter, gram, and second.

CHELATIING AGENT:

Chemical compound capable of forming multiple chemical bonds to a metal ion. Used to treat metal poisoning.

CHEMICAL:

Any element, chemical compound, or mixture of elements and/or compounds.

CHEMICAL CARTRIDGE RESPIRATOR:

Respirator using various chemical substances to purify inhaled air of certain contaminative gases or vapors. Typically effective for concentrations no more than 10 times the TLV of the contaminant if it has warning properties (odor or irritation) below the TLV.

CHEMICAL FAMILY:

Group of single elements or compounds with a common general name.

CHEMICAL FORMULA:

Gives the number and kinds of atoms that comprise a molecule of a material.

CHEMICAL NAME:

Scientific designation of name that clearly identifies chemical for hazard evaluation purposes.

CHEMICAL PNEUMONITIS:

Inflammation of the lungs caused by accumulation of fluids due to chemical irritation.

CHEMICAL REACTIVITY:

Ability of a material to chemically change. Undesirable and dangerous effects such as heat, explosions, or the production of noxious substances can result.

CHEMTREC:

24-hour toll free telephone number (800-424-9300), intended primarily for use by those who respond to chemical transportation emergencies. Established by the Chemical Manufacturer's Association.

CHEMILUMINESCENCE:

Emission of light during a non-combustible chemical reaction.

CHLORACNE:

Acne-like eruption caused by excessive contact with certain compounds.

CHEMICAL HYGIENE PLAN (CHP):

Per 29 CFR 1910.1450, OSHA standard; "Occupational Exposures to Hazardous Chemicals in Laboratories." Effective 5/1/90. A written plan that includes specific work practices, standard operating procedures, equipment, engineering controls, and policies to ensure that employees are protected from hazardous exposure levels to all potentially hazardous chemicals in use in their work areas. The OSHA standard provides for training, employee access to information, medical consultations, examinations, hazard identification procedures, respirator use, and record keeping practices.

CHRONIC EFFECT:

Adverse effect on a human or animal body with symptoms that develop slowly over a long period of time or that recur frequently.

CHRONIC EXPOSURE:

Long-term contact with a substance.

CHRONIC TOXICITY:

Adverse effects resulting from repeated doses of or exposures to a material over a relatively prolonged period of time. Ordinarily used to denote effects noted in experimental animals.

CNS:

Central Nervous System, the brain and spinal cord.

COEFFICIENT OF WATER/OIL DISTRIBUTION:

Also called the partition coefficient, it is the ratio of the solubility of a chemical in water to its solubility in oil. Used to indicate how easily human or other organisms can absorb or store a material. Sometimes abbreviated Ko/w; may also be expressed as its logarithm, log Ko/w.

COMBUSTIBLE LIQUIDS:

Term used by NFPA and DOT to classify certain liquids that will burn, on the basis of flash points. NFPA and DOT generally define "combustible liquids" as having a flash point of 100F or higher. They do not ignite as easily as flammable liquids; however, they can be ignited under certain conditions, and must be handled with caution.

COMMON NAME:

Designation for material other than chemical name, such as code, trade, brand, or generic name.

COMPRESSED GAS:

Material contained under pressure (dissolved gas, liquefied by compression or refrigeration).

CONCENTRATION:

Relative amount of a substance when combined or mixed with other substances.

CONDITIONS TO AVOID:

Conditions encountered during handling or storage that could cause a substance to become unstable.

CONFINED SPACE:

Any area that has limited openings for entry and exit that would make escape difficult in an emergency, has a lack of ventilation, contains known and potential hazards, and is not intended nor designated for continuous human occupancy.

CONJUNCTIVITIS:

Inflammation of conjunctiva, the delicate membrane that lines eyelid and covers the eyeball.

CONTAINER:

Any bag, barrel, bottle, box, can, cylinder, drum, reaction vessel, storage tank, or the like that contains a hazardous chemical. Under the Hazard Communication Standard pipes or piping systems, and engines, fuel tanks, or other operating systems in a vehicle are not considered to be containers.

CORNEA:

Transparent structure of the external layer of the eyeball.

CORROSION RATE:

Expressed in inches per year; accompanied by temperature.

CORROSIVE:

Liquid or solid that causes visible destruction or irreversible alterations in skin tissue at site of contact, or, in the case of leakage from its packaging, liquid that has severe corrosion rate on steel.

CRITICAL PRESSURE/TEMPERATURE:

Temperature above which a gas cannot be liquefied by pressure. The critical pressure is that pressure required to liquefy a gas at its critical temperature.

CRYOGENIC:

Relating to extremely low temperature as for refrigerated gases.

cu ft, ft3:

Cubic foot. Cu ft is more usual.

cu m, m3:

Cubic meter. m3 is preferred.

CURETTAGE:

Cleansing of a diseased surface.

CUTANEOUS:

Pertaining to the skin.

CYANOSIS:

Dark purplish coloration of skin and mucous membrane caused by deficient oxygenation of the blood.

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D  (Return to Top)

DANGEROUSLY REACTIVE MATERIAL:

Material that can react by itself or with water/air producing hazardous condition.

DECOMPOSITION:

Breakdown of a material or substance into parts or elements or simpler compounds.

DEFATTING:

Removal of natural oils from the skin by fat-dissolving solvents or other chemicals.

DELIQUESCENT:

Water soluble salts (usually powdered) absorb moisture from air and to soften or dissolve as a result.

DEMULCENT:

Material capable of soothing or protecting inflamed, irritated mucous membranes.

DENSITY:

Ratio of weight to volume of a material, usually in grams per cubic centimeter.

DEPRESSANT:

A substance that reduces a bodily functional activity or an instinctive desire, such as appetite.

DERMAL:

Used on or applied to the skin.

DERMAL TOXICITY:

Ratings corresponding to the following definitions are derived from data obtained from the test methods as described in 16 CFR 1500.40 and categories of toxicity as described in 16 CFR 1500.3.

NON-TOXIC:

The probable lethal dose of undiluted product to 50% of the test animals determined from dermal toxicity studies (LD50) is greater than 2 grams per kilogram of body weight.

TOXIC:

The probable lethal dose of undiluted product to 50% of the test animals determined from dermal toxicity studies (LD50) is greater than 200 milligrams and less than or equal to 2 grams per kilogram of body weight.

HIGHLY TOXIC:

The probable lethal dose of undiluted product to 50% of the test animals determined from dermal toxicity studies (LD50) is less than or equal to 200 milligrams per kilogram of body weight.

DERMATITIS:

Inflammation of the skin.

DESIGNATED REPRESENTATIVE:

Any individual or organization to whom an employee gives written authorization to exercise such employee's rights under the Hazard Communication Standard.

DESIGNATED AREA:

An area of (or device within) a lab to be used for work with "select carcinogens", reproductive toxins, and other materials which have a high degree of acute toxicity. An administrative control intended to minimize the potential for employee exposure to hazardous chemicals.

DIAPHORESIS:

Perspiration, especially profuse.

DIKE:

A barrier constructed to control or confine hazardous substances and prevent them from entering sewers, ditches, streams, or other flowing waters.

DILUTION VENTILATION:

Air flow designed to dilute contaminants to acceptable levels.

DISTRIBUTOR:

A business, other than a chemical manufacturer or importer, which supplies hazardous chemicals to other distributors or to employers.

DRY CHEMICAL:

Powdered fire extinguishing agent, usually composed of sodium bicarbonate, potassium bicarbonate, etc.

DUST:

Solid particles suspended in air produced by some mechanical process, such as crushing, grinding, abrading, or blasting. Most dusts are an inhalation, fire, and dust explosion hazard.

DYSPLASIA:

An abnormality of development.

DYSPNEA:

Sense of difficulty in breathing; shortness of breath.

DYSURIA:

Difficult or painful urination.

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E  (Return to top)

EDEMA:

Abnormal accumulation of clear, watery fluid in body tissue.

EFFECTIVE CONCENTRATION (EC50):

Concentration of a material in water, a single dose which is expected to cause a biological effect on 50% of a group of test animals.

ELECTROLYTE:

Non-metallic substance that conducts electric current in solution by moving ions rather than electrons.

EMBOLISM:

Obstruction of a blood vessel by a transported clot, a mass of bacteria, etc.

EMBRYO:

Organism in the early stages of development before birth.

EMBRYOTOXIN:

Material harmful to a developing embryo at a concentration that has no adverse effect on the pregnant female.

EMETIC:

Agent that induces vomiting.

EMPHYSEMA:

Irreversibly diseased lung condition in which the alveolar walls have lost their resiliency, resulting in an excessive reduction in the lungs' capacity.

EMPLOYEE:

A worker who may be exposed to hazardous chemicals under normal operating conditions or in foreseeable emergencies.

EMPLOYER:

A person engaged in a business where chemicals are either used, distributed, or are produced for use or distribution, including a contractor or subcontractor.

ENDOTHERMIC:

A chemical reaction that absorbs heat.

ENGINEERING CONTROLS:

Systems that reduce potential hazards by isolating the worker from the hazard or by removing the hazard from the work environment. Methods include ventilation, isolation, and enclosure.

EPIDEMIOLOGY:

Science that deals with the study of disease in a general population.

EPIPHORA:

Excessive flow of tears.

EPISTAXIS:

Nosebleed.

ERGONOMICS:

Study of human characteristics for the appropriate design of living and work environments.

ERYTHEMA:

Abnormally red skin from capillary congestion.

ETIOLOGY:

All of the factors that contribute to the cause of a disease or an abnormal condition.

EVAPORATION RATE:

Rate at which a particular material will vaporize when compared to the rate of vaporization of a known material. Evaporation rate can be useful in evaluating the health and fire hazards of a material.

EXPLOSIVE:

Material that produces a sudden, almost instantaneous release of pressure, gas, and heat when subjected to abrupt shock, pressure, or high temperature.

EXPOSURE OR EXPOSED:

State of being open and vulnerable to a hazardous chemical by inhalation, ingestion, skin contact, absorption, or any other course; includes potential (accidental or possible) exposure.

EXPOSURE LIMITS:

Concentration in air of a chemical that is thought to be acceptable.

EXTINGUISHING MEDIA:

Fire extinguisher or extinguishing method appropriate for use on specific material.

EYE IRRITATION:

Ratings corresponding to the following definitions are derived from data obtained from test methods described in the 16 CFR 1500.42 graded pursuant to the Draize Scale for scoring ocular lesions and temporal reversibility criteria as set forth in NAS Publication 1138.

1. PRACTICALLY NON-IRRITATING:
   The undiluted product, when instilled into the eyes of rabbits produces no noticeable irritation, or slight transient conjunctiva irritation. (Average Draize score 0.00-15.0).
2. SLIGHTLY IRRITATING:
   The undiluted product, when instilled into the eyes of rabbits, produces slight to moderate conjunctiva irritation, slight corneal involvement, and/or slight iritis. (Average Draize score 15.1-25.0).
3. MODERATELY IRRITATING:
   The undiluted product, when instilled into the eyes of rabbits, produces moderate corneal involvement with or without severe iritis. (Average Draize score range 25.1-50.0). The effects clear within 21 days.
4. SEVERELY IRRITATING (OR CORROSIVE):
   The undiluted product, when instilled into the eyes of rabbits, produces severe corneal involvement with or without severe iritis. (Average Draize score range 50.1-110.0). The effects persist for 21 days or more.

Glossary--continued