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Safety Using Chemical Reagents

Articles on Lab Safety

Always carefully read:

  • the reagent label and
  • the material safety data sheet (MSDS)

before working with any new and unfamiliar chemical reagent. Issues to research and think carefully about before using a new reagent include the following:

  • Chemical compatibility – Is this reagent known to be incompatible with any other reagents with which you or others in the laboratory might be working?
  • Chemical reactivity – Is the reagent a strong oxidizer? Reductant? Does it react with moisture? Oxygen?
  • Flammability – Is this reagent flammable?
  • Volatility – Is this reagent volatile?
  • Toxicity – Is the reagent toxic? Is it a mutagen? Carcinogen? What are the symptoms of exposure?
  • Handling – What personal protective equipment should one use in working with this reagent? Gloves? What kind of gloves? Safety glasses? Should it be handled in a hood?
  • Accidents – How should this material be cleaned up in case of a spill?
  • Emergencies – What kinds of emergencies could arise from use/misuse of this chemical? Are you prepared to deal with these?

Reagent Labels
Material Safety Data Sheets
Basic Format of an MSDS
Major Sections of MSDS

Reagent Labels

 

Reagent labels provide an extremely useful first means of defense in identifying the potential hazards presented by use of a specific reagent. The Occupational Health & Safety Administration (OSHA) requires all manufacturers to label their products with the name of the material, any relevant hazard warnings, and their name. Always read the label before you plan to use any chemical or biological reagent. Labels can tell you a lot about a reagent: Its name, chemical formula, the name and address of the manufacturer, the reagent’s physical properties, any health hazards associated with its use, and information on how to handle and store the reagent. While reagent labels do provide a lot of useful safety information, it is important to stress that they aren’t intended to serve as a researcher’s sole or even primary means of safety information on a chemical. They are intended to provide an immediate warning sufficient to prompt you, the user, to read more detailed information such as that provided by Material Safety Data Sheets (MSDS’s).

Most labels use a visual labeling system such as that developed by the National Fire Protection Association (NFPA) in order to provide a swift visual means of determining the potential hazards represented by a reagent. In brief, the NFPA system is based on a diamond composed of four color-coded squares each containing an integer ranging between 0 and 4 that represented the intensity of the hazard represented by the reagent in four different categories:

  • health (blue),
  • flammability (red) ,
  • reactivity (yellow), and
  • special hazards (white).

The higher the number the more significant the hazard represented by the chemical in that particular area. So, zero signals that the reagent poses a mimimum hazard while 4 indicates that the reagent poses a severe or potentially life-threatening hazard to the user which means that the reagent should be used only with extreme caution. It is important to stress that just because a reagent may have a zero hazard number in a specific category doesn’t mean that it is harmless. Handle every reagent with due care.

There are a number of different codes used to identify special hazards. These include: ox (oxidant), ACI (acid), ALK (base), COR (corrosive), and a W with a slash through it (water reactive).

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Material Safety Data Sheets

 

Material Safety Data Sheets or MSDSs are intended (the key word here) to provide a comprehensive source of written information about the properties, handling, and transport of chemical reagents. All manufacturers are required to provide users with an MSDS for each reagent that they sell. All employers including academic institutions are required to provide the relevant MSDS to any employee working with that reagent upon request. Although it would be ideal to have a copy of all of the relevant MSDSs in each and every laboratory, it is not very practical. Consequently it is important for you to contact your Office of Environmental Health and Safety in order to determine where MSDSs are kept at your workplace. Also, always consult the most recent version available of an MSDS. Note that you can always call the manufacturer of any chemical you use and request a copy of the MSDS be faxed to you. Many manufacturers including Sigma-Aldrich now provide these MSDSs on their website. There are also a number of excellent websites (see the reference section) that provide a wide range of reagent MSDSs for general use. . In this way, you can obtain and maintain your own set of copies of MSDS’s for the reagents with which you will work in the laboratory.

In practice there are problems with the quality of information on some MSDS’s which has led to recent criticism of MSDS’s by the research community (see Ritter, S.K. C&E News 2004, 83(6), 24-26. “Material Safety Data Sheets Eyed.”) If you are working with hazardous materials, then you are strongly advised to obtain several MSDS’s for these materials and to cross check the information on them before you use that reagent. If you find any inconsistencies or have any concerns about how to use the reagent in question safely in the lab, consult your advisor and your Office of Environmental Health and Safety for advice.

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Basic Format of an MSDS

 

Today most MSDS’s follow a 16-section format recommended by the American National Standards Institute (ANSI) in the early 1990’s and subsequently endorsed by OSHA.

An excellent introduction to the ANSI formatted MSDS is available on-line at:
muextension.missouri.edu/xplor/agguides/agengin/g01913.htm

Oklahoma State Office of Environmental Health and Safety has developed a good set of questions to use when examining a new MSDS that is available on-line at:
www.pp.okstate.edu/ehs/hazcom/hc-msds.htm

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The major sections of an MSDS are:

 

1. Reagent and Company Identification

This section provides the common chemical and trade names for the chemical reagent as well as contact information, useful in case of emergency, for the chemical supplier. This section will also provide the date on which the MSDS was prepared. Whenever possible consult the latest version of an MSDS currently available.

2. Reagent Composition

In the case of reagents that are sold as mixtures, this section provides composition information for any known health hazards that are present and which constitute more than 0.1% of the material. This section also provides information on the safe exposure limits such as the OSHA permissible exposure limit.

3. Identification of Potential Hazards

The third section of the MSDS provides information on major hazards that may be associated with use and handling of reagent such as toxicity and flammability.

4. First Aid Measures

Appropriate measures for treatment of injuries by inhalation, ingestion, and eye and/or skin contact are outlined in this section.

5. Fire Fighting Measures

This section provides information on flammability and/or explosive nature of the reagent and details the appropriate equipment and or measures to take if a fire or explosion takes place involving the reagent.

6. Accidental Release Measures

Procedures and materials that should be used in case of an accidental spill are provided in this section of the MSDS.

7. Reagent Handling and Storage

This section provides useful information regarding the proper methods to use in handling and storing the reagent in the laboratory. Chemical incompatibilities, information about the potential for the formation of peroxides (explosion hazards) upon extended storage, need for a flammable storage cabinet, etc. are detailed here.

8. Exposure Controls and Personal Protection

This section provides information on the types of personal protective equipment that may be required in order to safely handle and work with the reagent.

9. Physical and Chemical Properties

Useful fundamental data regarding the physical and chemical properties of the reagent such as the form, color, odor, melting point, boiling point, solubility in water, vapor pressure, are provided in this section. This information can be extremely helpful in determining how to properly handle and store a reagent.

10. Reagent Stability and Reactivity

If the material is or could become unstable, this section will provide information on any conditions that might produce hazardous reactions and/or decomposition of the reagent.

11. Toxicological Information

Information on the toxicity of the reagent is detailed here. Data usually provided include the LD50 (lethal dose 50; single, usually oral, dose of the reagent that results in the death of 50% of test subjects) and the LC50 (lethal concentration 50; concentration of an inhaled volume of air containing the reagent that produces death in 50% of test subjects).

12. Ecological Information

This section provides any available information concerning the effect that release of the reagent might have on plants and/or animals in the environment.

13. Disposal Considerations

Information on the appropriate methods that may be used to dispose of waste containing the reagent are described in this section of the MSDS.

14. Transport Information

This section provides information on how the reagent may be safely transported.

15. Regulatory Information

Any relevant regulatory information relevant to risks and safe use of the reagent are provided in this section.

16. Additional Information

This section may contain the name of the author of the MSDS, any references that he/she used to prepare the MSDS, and often contains legal disclaimers regarding the use of the MSDS that are intended to protect the manufacturer against liability.

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References