APPENDIX D: Explanation Of Material
Safety Data Sheet Information
Per the federal Occupational Safety and
Health Administration (OSHA) Laboratory Standard, laboratories are
required to keep Material Safety Data Sheets (MSDSs) that are received
from the manufacturer and maintain them in such a way that they are accessible
to laboratory personnel. A system should be in place to catalogue MSDSs
when received. If an MSDS is not received with a shipment, it may easily
be obtained by requesting one from the manufacturer. In many cases, the
MSDS may have been sent to the “Safety Officer”, and may have
been received by the Chemical Hygiene Officer or EHS. Several chemical
distributors have MSDSs available through the internet. The EHS web page
has pointers to many of these sites at http://www.princeton.edu/~ehs.
In addition, the Office of Environmental Health and Safety has a database
of over 40,000 MSDSs. Contact EHS at 8-5294 for assistance.
Following is an explanation that is provided to help you interpret the
information found on manufacturer’s MSDSs. While the format of these
data sheets varies from manufacturer to manufacturer, certain components
appear on each sheet.
Product Identification (top)
This section gives the name and address of the manufacturer and an
emergency phone number where questions about toxicity and chemical hazards
can be directed.
||Commercial or marketing name
||Approved chemical name and/or synonyms
||Group of chemicals with related physical and chemical properties
||Chemical formula, if applicable; i.e., the conventional scientific
definition for a material.
||Number assigned to chemicals or materials by the Chemical Abstracts
Service, where applicable
Hazardous Ingredients Of Mixtures (top)
This section describes the percent composition of the substance, listing
chemicals present in the mixture. If it was tested as a mixture, lists
chemicals that contribute to its hazardous nature. Otherwise, lists
ingredients making up more than 1% and all carcinogens.
The OSHA permissible exposure limit (PEL),
National Institute for Occupational Safety and Health (NIOSH) recommended
exposure limit (REL), and/or the American Conference of Governmental
Industrial Hygienists (ACGIH) threshold limit value
(TLV) will also be listed, if appropriate. The OSHA PEL is the
regulated standard, while the others are recommended limits. The PEL
is usually expressed in parts per million parts of air (ppm) or milligrams
of dust or vapor per cubic meter of air (mg/m3). It is usually a time
weighted average (TWA) - concentration averaged over an eight-hour
day. Sometimes, a STEL or short
term exposure limit may be listed. The STEL is a 15-minute TWA
which should not be exceeded. A ceiling limit,
is a concentration which may not be exceeded at any time. A skin
notation means that skin exposure is significant in contributing to
the overall exposure.
Physical Data (top)
This section outlines the physical properties of the material. The information
may be used to determine conditions for exposure. The following information
is usually included:
Boiling Point: temperature at which liquid
changes to vapor state
Melting Point: temperature at which a solid
begins to change to liquid.
Vapor Pressure: a measure of how volatile
a substance is and how quickly it evaporates. For comparison, the VP
of water (at 20o C) is 17.5 mm Hg, Vaseline (non-volatile) is close
to 0 mm Hg, and diethyl ether (very volatile) is 440 mm Hg.
Vapor Density (air=1):
weight of a gas or vapor compared to weight of an equal volume of air.
Density greater than 1 indicates it is heavier than air; less than 1
indicates it is lighter than air. Vapors heavier than air can flow along
just above ground, where they may pose a fire or explosion hazard.
Specific Gravity (water=1): ratio of volume
weight of material to equal volume weight of water.
Solubility in Water: percentage of material
that will dissolve in water, usually at ambient temperature. Since the
much of the human body is made of water, water-soluble substances more
readily absorb and distribute.
Appearance/Odor: color, physical state at
room temperature, size of particles, consistency, odor, as compared
to common substances. Odor threshold refers to the concentration required
in the air before vapors are detected or recognized.
% Volatile by Volume: Percentage of a liquid
or solid, by volume, that evaporates at a temperature of 70oF.
Evaporation Rate: usually expressed as a
time ratio with ethyl ether = 1, unless otherwise specified.
Viscosity: internal resistance to flow exhibited
by a fluid, normally measured in centiStoke time or Saybolt Universal
Other Pertinent Physical Data: information
such as freezing point is given, as appropriate.
Fire And Explosion Hazard Data (top)
This section includes information regarding the flammability of the
material and information for fighting fires involving the material.
Flashpoint: the lowest temperature at which
a liquid gives off enough vapor to ignite when a source of ignition
Autoignition Temperature: the approximate
temperature at which a flammable gas-air mixture will ignite without
spark or flame. Vapors and gases will spontaneously ignite at lower
temperatures in oxygen than in air.
Flammable Limits: the lower explosive limit
(LEL) and upper explosive limit (UEL) define the range of concentration
of a gas or vapor in air at which combustion can occur. For instance,
an automobile carburetor controls this mixture - too lean (not enough
chemical) or too rich (not enough air, as when you flood your engine),
will not ignite.
Extinguishing Media: appropriate extinguishing
agent(s) for the material.
Fire-fighting Procedures: Appropriate equipment
and methods are indicated for limiting hazards encountered in fire situations.
Fire or Explosion Hazards: Hazards and/or
conditions that may cause fire or explosions are defined.
Health Hazard Data (top)
This section defines the medical signs and symptoms that may be encountered
with normal exposure or overexposure to this material or its components.
Information on the toxicity of the substance may also be presented.
Results of animal studies are most often given. i.e. LD50 (mouse)=250
mg/kg. Usually expressed in weight of chemical per kg of body
weight. LD50 or lethal dose 50 is the dose of a substance that
will cause the death of half the experimental animals. LC50 is the concentration
of the substance in air that will cause the death of half the experimental
Health hazard information may also distinguish the effects of acute
(short term) and chronic (long-term) exposure.
Emergency And First Aid Procedures (top)
Based on the toxicity of the product, degree of exposure and route of
contact (eye, skin, inhalation, ingestion, and injection), emergency
and first aid procedures are recommended in this section.
Additional cautionary statements, i.e., Note to Physician,
for first aid procedures, when necessary, will also appear here.
Reactivity Data (top)
This section includes information regarding the stability of the material
and any special storage or use considerations.
Stability: “unstable” indicates
that a chemical may decompose spontaneously under normal temperatures,
pressures, and mechanical shocks. Rapid decomposition produces heat
and may cause fire or explosion. Conditions to avoid are listed in this
Incompatibility: certain chemicals, when
mixed may create hazardous conditions. Incompatible chemicals should
not be stored together.
Hazardous Decomposition Products: chemical
substances that may be created when the chemical decomposes or burns.
Hazardous Polymerization: rapid polymerization
may produce enough heat to cause containers to explode. Conditions to
avoid are listed in this section.
Spill, Leak And Disposal Procedures (top)
This section outlines general procedures, precautions and methods for
cleanup of spills. Appropriate waste disposal methods are provided for
safety and environmental protection.
Personal Protection Information (top)
This section includes general information about appropriate personal
protective equipment for handling this material. Many times, this section
of the MSDS is written for large-scale use of the material. Appropriate
personal protection may be determined by considering the amount of the
material being used and the actual manipulations to be performed.
Eye Protection: recommendations are dependent
upon the irritancy, corrosivity, and special handling procedures.
Skin Protection: describes the particular
types of protective garments and appropriate glove materials to provide
Respiratory Protection: appropriate respirators
for conditions exceeding the recommended occupational exposure limits.
Ventilation: airflow schemes (general, local)
are listed to limit hazardous substances in the atmosphere.