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Glossary

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Acute or Chronic Toxins or Poisons damage or interfere with the metabolism of living tissue.

Acutely toxic substances inflict their damage as a result of a single exposure or exposure of short duration. The Minnesota Pollution Control Agency (MPCA) defines the following as acutely toxic:

Oral LD50 (rat) < 50 mg/kg

Inhalation LC50 (rat) < 2mg/L

Dermal LD50 (rabbit) <200 mg/kg.

Allergen/Sensitizer produces skin or lung hypersensitivity. Common examples include formaldehyde, dichromates, and certain phenols. A

Bonding is a procedure which eliminates static electrical charge differences between two or more objects. It does not eliminate the static charge, but equalizes the potential between the objects bonded so that a spark will not occur between them.

Carcinogens promote or initiate the development of malignant or benign growths in living tissue. Carcinogens can be listed as "known," "suspected," or "potential." Common examples include formaldehyde, benzene, and colchicine.

Chronically toxic substances cause damage after repeated exposures or lower dose exposures of a longer duration. Also associated with some chronic toxins are long latency period in which the cumulative effects of the substance are not evident for many years. All carcinogens, and many metals and their derivatives (arsenic, cadmium, lead, mercury and nickel) are chronically toxic substances.

Combustible liquid means any liquid having a flashpoint at or above 100 0F (37.8 0C) but below 2000F (93.3 0C ), except any mixture having components with flashpoint of 200 0F (93.3 0C) or higher, the total volume of which make up 99% or more of the total volume of the mixture.

Compressed gas means a gas or mixture of gases having, in a container, an absolute pressure exceeding 40 psi at 700F (21.1 0C) or exceeding 130 0F (54.4 0C) regardless of the pressure at 700F (21.1C). It also refers to a liquid having a vapor pressure exceeding 40 psi at 1000F (93.3 0C) as determined by ASTM D-323-72.

Corrosives visibly erode and irreversibly alter living tissue, and are especially damaging to the eyes. Severe bronchial irritation occurs from the inhalation of the vapors or mists of these types of chemicals. Corrosives are subdivided into three categories:

Strong acids such as nitric, hydrochloric, sulfuric and phosphoric.

Strong bases such as ammonium, potassium hydroxide, and sodium hydroxide.

Dehydrating agents such as concentrated sulfuric acid and sodium hydroxide.

Cutaneous hazards are caused by target organ substances that affect the dermal layer of the body.

Embryotoxins are poisonous to the embryo without necessarily affecting the mother

Flash point is the lowest temperature at which the vapor above the liquid will ignite if an ignition source is present. The flash point for ethyl ether is -49 0 C

Grounding is a procedure which eliminates a potential difference between an object and the ground (earth). An adequate ground continuously discharges a charged conductive body.

Hepatotoxins are target organ substances that produce liver damage.

Ignition/Autoignition temperature is the minimum temperature required to initiate or cause self-sustained combustion which is independent of a spark or flame source.

Irritants cause reversible inflammation of living tissue. Examples include sodium chloride, and magnesium hydroxide.

Lethal Dose (LD50) is the quantity of material that when ingested, injected or applied to the skin as a single dose will cause the death of 50% of the test animals.

Limits of flammability describe the range of concentrations in mixtures with air that will propagate flame and explode. They include the following:

LEL or lower flammable limit/lower explosive limit: the percent by volume concentration below which the mixture is too lean to burn.

UEL or upper flammable limit/upper explosive limit: the percent by volume concentration below which the mixture is too rich to burn.

The flammable range (explosive range) consists of all the concentrations between these two limits.

Mutagens induce changes in DNA and living cells.

Nephrotoxins are target organ substances that produce kidney damage.

Neurotoxins are target organ substances that produce toxic effects on the nervous system.

Permissible Exposure Limits (PELs) are OSHA-regulated values which define the legal air contaminant concentrations in the workplace. PELs are expressed in ppm (parts of vapor or gas per million parts of air by volume at room temperature and atmospheric pressure) or mg/m3 (milligrams of particulate per cubic meter of air.

Reproductive Toxins exhibit harmful effects in either the male or female reproductive system or in the developing fetus. Reproductive toxins can be categorized as either embryotoxins, mutagens or terotagens.

Select Carcinogens refers to the carcinogens that are either regulated by OSHA as a carcinogen; or listed as "known to be carcinogens in the Annual Report on Carcinogens published by the National Toxicology Program (NTP) latest edition ( or listed under Group 1 "carcinogenic to humans" by the International Agency for Research Cancer Monographs (IARC) latest editions; or listed by IARC in Group 2A or 2B or listed as "reasonably anticipated to be carcinogens" by NTP.

Spontaneous combustion or ignition takes place when, without application of an external heat source, a substance reaches its ignition

Target Organ Substances exert a toxic effect on one or more of the various organs or systems of the human body. Target organ substances include hepatotoxins, nephrotoxins, cutaneous hazards, eye hazards, agents that act on the blood or hematopoietic system by decreasing hemoglobin function, respiratory hazards, and acute or chronic toxins or poisons.

Terotagens cause physical or functional defects in the developing embryo. Compromised survivability or birth defects result from significant exposure.

Threshold Limit Values (TLVs) refer to airborne concentrations of substances and represent conditions under which it is believed that nearly all workers can be repeatedly exposed day after day without adverse health effects. TLVs have been determined by the American Conference of Governmental Industrial Hygienists, ACGIH. In general, the lower the LD50, PEL, or TLV, the more hazardous the material. TLVs are subclassified as:

Time-weighted average (TLV-TWA) is the time-weighted average concentration for a normal 8-hour workday and a 40-hour work week.

Short-Term Exposure Limit (TLV-STEL) is the concentration to which persons can be exposed for a period of up to 15 minutes continuously without suffering irritation, chronic or irreversible tissue change or necrosis.