SAFETY IN THE LABORATORY

Safety First

The concern for laboratory safety can never be overemphasized. Most students who are involved in biochemistry laboratory activities have progressed through several years of college lab work without even a minor accident. This record is, indeed, something to be proud of; however, it should not lead to overconfidence.

You must always be aware that chemicals used in the laboratory are potentially toxic, irritating, and flammable. However, such chemicals are a hazard only when they are mishandled or improperly disposed of. It is my experience as a lab instructor for 30 years that accidents happen least often to those who come to each lab session mentally prepared and with a complete understanding of the experimental procedures to be followed. Because dangerous situations can develop unexpectedly, though, you must be familiar with general safety practices, facilities, and emergency actions. When we work in the lab, we must also have a special concern for the safety of lab mates. Carelessness on the part of one person can often cause injury to others.

Material Safety Data Sheets

The procedures in this book are designed and described with an emphasis on safety. However, no amount of planning or pretesting of procedures substitutes for awareness and common sense on the part of the student. All chemicals usedin the procedures outlined here must be handled with care and respect. The useof chemicals in all U.S. workplaces, including academic research and teaching labs, is regulated by the Federal Hazard Communication Standard, a document Chapter 1 • Introduction to the Biochemistry Laboratory 3 written by the Occupational Safety and Health Administration (OSHA).1 Specifically, the OSHA standard requires all workplaces where chemicals are used to do the following: (1) develop a written hazard communication program; (2) maintain files of Material Safety Data Sheets (MSDS)on all chemicals used in that workplace (an MSDS is a detailed description of the properties of a chemical substance, the potential health hazards, and the safety precautions that must be taken when handling it); (3) label all chemicals with information regarding

hazardous properties and procedures for handling; and (4) train employees in th proper use of these chemicals. Several states have passed “right-to-know” legislation that amends and expands the federal OSHA standard. If you have an interest in or concern about any chemical used in the laboratory, the MSDS may be obtained from your instructor or laboratory director or from the Internet (www.sigma-aldrich.com, for example). The actual form of an MSDS for a chemical may vary, but certain specific information must be present. Figure 1.1 is a partial copy of the MSDS for glacial acetic acid, a reagent often used in biochemical research. All chemical reagent bottles in a workplace, lab, or stockroom must be labeled to identify potential hazardous materials and to specify personal protection necessary for handling. One standard hazard communication system used for this

purpose is the Hazardous Materials Identification System (HMIS® III Wall Chart containing an HMIS® III Label in the lower left-hand corner is shown in Figure 1.2). The health, flammability, physical hazard, and personal protection codes for the chemical reagent are summarized on the bottle label for quick identification.

Safe Practices in the Biochemistry Laboratory

It is easy to overlook some of the potential hazards of working in a biochemistry laboratory. Students often have the impression that they are working less with chemicals and more with natural biomolecules; therefore, there is less need for caution. However, this is not true; many reagents used are flammable and toxic. In addition, materials such as fragile glass (disposable pipets), sharp objects (needles, razor blades, etc.), and potentially infectious biological materials (blood, bacteria, viruses) must be used and disposed of with caution. The extensive use of electrical equipment, including hot plates, stirring motors, and high-voltage power supplies for electrophoresis, presents special hazards.

Proper disposal of all waste chemicals, sharp objects, and infectious agents is essential not only to maintain safe laboratory working conditions, but also toprotect the general public and your local environment. Some of the liquid chemical reagents and reaction mixtures from experiments are relatively safe and may be disposed of in the laboratory drainage system without causing environmental damage. However, special procedures must be followed for the use and disposal of most reagents and materials. Often this means that your instructor will provide detailed information on proper use procedures. In some cases, proper\

FIGURE 1.1 Partial MSDS for glacial acetic acid. MSDS information is subject to change. For the most current version, contact SigmaAldrich. Courtesy of Sigma-Aldrich Corp., St. Louis, MO;www.sigmaaldrich.com.

FIGURE 1.2 HMIS®III Wall Chart containing an HMIS®III label (lower left-hand corner) for glacial acetic acid displaying the hazard indices for the chemical. HMIS®III is a registered trademark of the National Paint & Coatings Association, Inc. (NPCA).It is used with permission and may not be further reproduced. NPCA has granted anexclusive license to produce and distribute HMIS®III materials to J. J. Keller & Associates, Inc. Those wishing to utilize the HMIS®III system should contact J. J. Keller at 1-800-327-6868 or www.jjkeller.com

disposal will require the collection of waste materials from each laboratory worker, and the institution will be responsible for removal. For each procedure described in this book, appropriate handling of all reagents, materials, and equipment will be recommended.

It is essential that all students be aware of the potential hazards of working in a biochemistry laboratory. A set of rules is an appropriate way to communicate the importance of practicing safe science. The general rules outlined in Figure 1.3 serve as guidelines. Your institution and instructor may have their own list of rules or may want to add guidelines for specific activities. Rules of laboratory safety and chemical handling are not designed to impede productivity, nor should they instill a fear of chemicals or of laboratory procedures. Rather, their purpose is to create a healthy awareness of potential laboratory hazards, to improve the efficiency of each student worker, and to protect the general public and the environment from waste contamination. The list of references at the end of this chapter includes books, journal articles, manuals, and Web sites describing proper and detailed safety procedures.

FIGURE 1.3 Guidelines for safety in the biochemistry laboratory.