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Prudent Practices in the Laboratory: Handling and Disposal of Chemicals
The cornerstone of a sound program for prudent laboratory practices is a process designed to comprehensively review the operations and potential hazards associated with each experiment1 over its life cycle. This review should take place before any work is conducted. The diverse nature of research and development activities makes it advisable to have such a process in place as part of the scientific method of experimentation. In laboratories where this preliminary survey is routinely practiced, it has proved to be useful in both the maintenance of safe laboratory operations and the minimization of chemical exposure and waste generation. Because of the diversity of types of researchers and laboratory work, such processes—both formal and informal—can help individuals associated with new, modified, or unfamiliar experiments or procedures to plan and work safely, responsibly, and productively. By first evaluating the work area, materials, equipment, and procedures in depth, hidden hazards may be identified and addressed. The pre-experiment review process can also help to ensure that every experiment and laboratory operation complies with all applicable laws, regulations, and other policies. Moreover, by addressing all relevant health, safety, and environmental issues when an experiment is first conceived, further research, scale-up, or development based on it can be made safer and more effective.
In this chapter the concept of experiment planning is addressed as the first step in ensuring that prudence is exercised in conducting laboratory operations. Because of the diversity in experiments, laboratory workers, facilities, and hazards, experiment planning can be a complex process for which it is impractical to structure rules. The committee's approach has been to consider the likely steps involved in conducting any chemical experiment. These range from developing a clear understanding of the goals and objectives of the project to providing for the acquisition and handling of materials and equipment all the way to the storage and ultimate disposal of all chemicals, both desired products and waste.
The steps to be considered in planning an experiment can be described by a flowchart such as the one depicted in Figure 1.2. (section 1.G), which shows the individual steps in a laboratory experiment. These steps, in turn, correspond to the different chapters of this book. For the experienced laboratory worker, these steps are understood intuitively, and the pre-experiment review is primarily a thought process, with perhaps a brief written description of the experiment plan. For others, the review of some or all steps on such a flowchart (and the corresponding chapters in this book), along with a more formal documentation process, is in order.
2.BLEVELS OF FORMALITY IN EXPERIMENT PLANNING
As mentioned above, the types of laboratory experiments are diverse and may be conducted by a wide range of practitioners whose skills and backgrounds may be enormously varied, even within a single discipline or institution. Thus, the degree of formality and documentation necessary for prudent planning is a matter of judgment. Decisions to be made in experiment planning will be affected by the knowledge and skills of the personnel, the scale of the experiments, the particular hazards of the materials or operations being contemplated, the institution's policies for planning and conducting experiments, and the regulatory environment in which the experiments are to be performed.
Because of this diversity among practitioners, what may pose a significant and unfamiliar challenge to one laboratory worker may be second nature to another. For example, the very limited skills of high school or undergraduate chemistry students may demand that extensive written planning of basic laboratory procedures take place before an experiment is attempted. For graduate students or seasoned research chemists, those same operations may be sufficiently familiar that pre-experiment review of an informal "mental checklist" and a single line entry in a laboratory notebook may, in such a circumstance, be entirely prudent in laboratory practice. Similarly, what may be a straightforward distillation of organic solvent to a Ph.D. graduate student in synthetic organic chemistry may be an unfamiliar and, thus, rather more hazardous procedure for even an experienced professor of theoretical chemistry.
To allow for these differences in level of experience, many institutions have established general guidelines for several different levels of formality, which are scaled according to the estimated risks. Depending on the situation, these might include (1) simple mental evaluation of hazards for straightforward experiments
Throughout this book the term experiment includes the entire range of laboratory operations from science classes to large-scale experimental programs involving many people over a considerable period of time, all of which require some degree of forethought.