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Understanding Material Safety Data Sheets

by schmidy last modified Apr 10, 2007 03:42 PM

The federal Occupational Safety and Health Administration (OSHA) Hazard Communication Standard requires manufacturers or distributors of hazardous materials to assess the physical and health hazards of the chemical or product. This information must be included in the Material Safety Data Sheet (MSDS), which must be provided to the purchaser. The Hazard Communication Standard requires that MSDSs be obtained and maintained for every chemical used in the workplace. The Laboratory Standard requires laboratories to keep MSDSs that are received from the manufacturer. The MSDSs must be accessible to personnel during all work hours.


Understanding MSDS information


The following sections are required on all material safety data sheets:

* Product Identification
* Hazardous Ingredients Mixture
* Physical Data
* Fire and Explosion Data
* Health Hazard Data
* Emergency and First Aid Procedures
* Reactivity Data
* Spill, Leak, and Disposal Procedures
* Personal Protection Information




Product Identification


This section lists the name and address of the manufacturer and an emergency phone number where questions can be directed. In addition you will find the following information:


Product Name: Commercial or marketing name
Synonym: Approved chemical name and/or synonyms
Chemical Family: Group of chemicals with related physical and chemical properties
Formula: Chemical formula, if applicable; i.e., the conventional scientific definition for a material
CAS Number: Number assigned to chemicals or materials by the Chemical Abstracts Service




Hazardous Ingredients Of Mixtures


This section describes the percent composition of the substance, listing hazardous chemicals in the product. Each hazardous component comprising 1% or more of the product must be listed. Carcinogens must be listed if they comprise at least 0.1% of the product.


Exposure limits, if available, are also provided for each hazardous component. 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 short term exposure limit STEL may be listed. The STEL is a 15 minute TWA which should not be exceeded. A ceiling limit (C), 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


This section outlines the physical properties of the material. This information may be used to determine conditions for exposure. For example, one can determine whether or not a chemical will form a vapor (vapor pressure), whether this vapor will rise or fall (vapor density), and what the vapor should smell like (appearance and odor). The following information is usually included:

  • Boiling Point (BP): temperature at which liquid changes to vapor state
  • Melting Point (MO): temperature at which a solid begins to change to liquid
  • Vapor Pressure (VP): expressed in mmHg. As a rule of thumb, higher vapor pressure materials evaporate more quickly.
  • Vapor Density: weight of a gas or vapor compared to weight of an equal volume of air (air =1). 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: ratio of volume weight of material to equal volume weight of water (water=1).
  • Solubility in Water: percentage of material that will dissolve in water.
  • Appearance/Odor: provides a brief description of the appearance and odor of the product.
  • % Volatile by Volume: Percentage of a liquid or solid, by volume, that evaporates at a temperature of 70 degrees F.
  • Evaporation Rate: the rate at which a material evaporates when compared to a known material's evaporation rate.
  • Viscosity: measurement of the flow properties of a material.
  • Other Pertinent Physical Data: information such as freezing point is given, as appropriate.



Fire And Explosion Hazard Data


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 is present.
  • Autoignition Temperature: the lowest temperature at which a flammable gas-air mixture will ignite without spark or flame.
  • 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.
  • Extinguishing Media: appropriate fire 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 which may cause fire or explosions.



Health Hazard Data


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 and route of entry may also be presented. Results of animal studies are most often given. i.e. LD50 (mouse)=250 mg/kg. Health hazard information may also distinguish the effects of acute (short term) and chronic (long-term) exposure.




Emergency And First Aid Procedures


Based on the toxicity of the product, degree of exposure and route of contact (eye, skin, inhalation, ingestion, injection), emergency and first aid procedures are recommended in this section.




Reactivity Data


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, or mechanical shocks. Rapid decomposition produces heat and may cause fire or explosion. Conditions to avoid are listed in this section.
  • Incompatibility: certain chemicals, when mixed may create hazardous conditions. Incompatible chemicals should not be stored together.
  • Hazardous Decomposition Products: chemical substances which 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


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


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 and use of the material. Personal protective equipment includes:

  • Eye Protection
  • Skin Protection
  • Respiratory Protection
  • Ventilation
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