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Research AdministrationBiohazards and Lab Safety:
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Hazard Potential |
Reactivity Hazard Rating |
Flammability Hazard Rating |
Health Hazard Rating |
0 = Minimal or insignificant |
Normally stable, even under fire conditions; will not react with water |
Materials that are normally stable; will not burn unless heated |
No significant risk to health |
1 = Slight |
Normally stable but can become unstable at high temperatures/pressures; may react mildly with water |
Materials that must be preheated before ignition will occur (liquids with flashpoints ³ 200° F) |
Irritation or minor reversible injury possible |
2 = Moderate |
Normally unstable; reacts violently with water; will readily undergo chemical change but will not detonate |
Materials that must be moderately heated before ignition will occur (liquids with flashpoints ³ 100° F and < 200° F) |
Temporary or minor injury may occur |
3 = Serious or high |
Capable of strong detonation/explosive reaction only in the presence of a strong initiating source (i.e., heat under confinement); reacts violently with water |
Materials capable of ignition under almost all normal temperature conditions (flashpoints £ 73° F and 100° F, boiling point ³ 100° F) |
Major injury likely unless prompt action and medical treatment are given |
4 = Sever or extreme |
Readily capable of detonation or explosive decomposition at normal temperatures and pressures |
Very flammable gases or very volatile flammable liquids (flashpoint £ 73° F, boiling point £ 100° F) |
Life-threatening; major or permanent damage may result from single or repeated exposure |
Material Safety Data Sheet information should be stored in an orderly fashion and must be readily available to all employees at all times. The MSDS information is useful for establishing parameters for a safe workplace and is invaluable if emergencies involving the chemical occur.
American National Standard Institute (ANSI) - A private, nonprofit organization that administers and coordinates U.S. efforts to establish business safety standards and guidelines
Code of Federal Regulations (CFR)- A codification of the rules published in the Federal Register by executive departments and agencies of the federal government
Chemical Abstracts service (CAS) - An index of chemical information provided by the American Chemical Society; the CAS number identifies specific chemicals indexed by the CAS
Combustible liquid - Any liquid having a flashpoint at or above 100° F (37.8° C); exception: any mixture of components with flashpoints of 200° F or higher if the total volume of that component makes up 99% of the mixture
Flammable liquids: lower explosive limit (LEL) and upper explosive limit (UEL) - The lower and upper limits of vapor and air concentration that can cause an explosion; these are reported as percentage
Flashpoint - The lowest temperature at which a liquid gives off enough vapor to be ignitable
Hazardous decomposition products - Products released upon exposure to aging, heating, burning, oxidation, or reaction; the shelf life should also be listed when applicable
National Fire Protection Association (NFPA) - Label system used to designate health, flammability, and reactivity risks associated with a product (uses a vertical line for scoring data)
Permissible exposure limit (PEL) - The minimum quantity (measured in parts per million [ppm] of chemical exposure before protective measures must be instituted; set by OSHA
Percent volatile by volume - Percentage of a liquid or solid that evaporates at room temperature; the higher the percentage, the faster the substance will evaporate
Specific gravity (SG) - Ratio of the weight of a volume of liquid to the weight of an equal volume of water at a specified temperature; if the SG is > 1.0, the liquid will sink in water, if the SG <1.0, the liquid will float in water
Threshold limit value (TLV) - An atmospheric concentration of a contaminant to which nearly all workers may be repeatedly exposed after a working lifetime, without adverse effect; a TLV < 10 indicates a very hazardous material
Threshold limit value - ceiling limit (TLV-C) - The amount of concentration that should not be exceeded, even for brief periods
Threshold limit value - short term exposure (TLV -STEL) - Maximum concentration for a continuous 15 minute exposure period; the most allowed are four such periods in a workday, with at least 60 minutes between exposure periods, as long as the allowable time-weighted average is not exceeded
Threshold limit value - time weighted average (TLV-TWA) - The allowable time-weighted average concentration for a normal 8-hour workday or 40-hour workweek
Vapor density (VD) - Relative density or weight of a vapor or gas compared with an equal volume of air; if VD is < 1.0, the vapor or gas will tend to rise in the air; if VD is >1.0, the vapor or gas will fall in the air; substances with high VD will collect in the bottom of tanks
Vapor Pressure (VP) - A measure of the pressure exerted by a saturated vapor above its liquid phase in a closed container (a high VP indicates that a liquid will evaporate easily)
Volatile - Used to describe a liquid that readily evaporates