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Prudent Practices in the Laboratory: Handling and Disposal of Chemicals
This chapter organizes the discussion of managing laboratory chemicals into five main topics: source reduction, acquisition, inventory and tracking, storage in stockrooms and laboratories, and recycling of chemicals and laboratory materials. As Chapter 1 makes clear, the concept of prudence in these areas requires knowledge of the hazards posed by laboratory chemicals and the formulation of reasonable measures to control and minimize the risks associated with their handling and disposal. It is not possible to eliminate risk altogether, but through informed risk assessment and careful risk management, laboratory safety can be greatly enhanced.
Laboratory workers, laboratory supervisors, and individuals who handle chemicals all will find essential information in this chapter. Each of these people has an important role to play in a chemical's life cycle at an institution, and each one of them should be aware that the wise management of that life cycle can not only minimize risks to humans and to the environment, but also decrease costs.
Prudent management of chemicals in laboratories must begin long before the actual arrival of the chemicals. When experiments have been carefully planned, laboratory workers can be confident that they have chosen the procedures for working with chemicals that meet the following goals:
to minimize quantities of chemicals to be used,
to minimize disposal of hazardous materials, and
to minimize risks.
Strategies for achieving the first three goals generally also are effective in achieving a fourth:
to minimize exposure of laboratory workers and storeroom and receiving personnel to hazardous materials.
4.B.1Importance of Minimizing Chemical Orders
In order to cut costs, manufacturing firms are increasingly asking for "just-in-time" delivery of raw materials. Laboratories might well borrow this strategy. A quantity of hazardous chemical not ordered is one to which workers are not exposed, for which appropriate storage need not be found, which need not be tracked in an inventory control system, and which will not end up requiring costly disposal when it becomes a waste.
In acquiring a chemical, it is important to do a life cycle analysis. All costs associated with the progress of each chemical through its lifetime at an institution must be considered. The purchase cost is only the beginning; the handling costs, human as well as financial, and the disposal costs must be taken into account as well. Without close attention to this aspect of managing chemicals in laboratories, orders are not likely to be minimized and unused chemicals can become a significant fraction of the laboratory's hazardous waste.
Institutions also need to minimize the amount of chemical accepted as a gift or as part of a research contract. More than one laboratory has been burdened with the cost of disposing of a donated chemical that was not needed. A "free" material can become a significant liability. The American Chemical Society's booklet Less Is Better: Laboratory Chemical Management for Waste Reduction (ACS, 1993) gives several reasons for ordering chemicals in smaller containers, even if that means using several containers of a material for a single experiment:
The risk of breakage is substantially reduced for small package sizes.
The risk of accident and exposure to the hazardous material is less when handling smaller containers.
Storeroom space needs are reduced when only a single size is inventoried.
Containers are emptied faster, resulting in less chance for decomposition of reactive compounds.
The large "economy size" often dictates a need for other equipment, such as smaller transfer containers, funnels, pumps, and labels. Added labor to subdivide the larger quantities into smaller containers, as well as additional personal protective equipment for the hazards involved, also may be needed.
If unused hazardous material must be disposed
Donated material can easily become a liability. A chemical engineering researcher accepted a 55-gallon drum of an experimental diisocyanate as part of a research contract. The ensuing research project used less than 1 gallon of the material, and the grantor would not take the material back for disposal No commercial incinerator would handle the material in its bulk form. The remaining material had to be transferred to 1-liter containers and sent as Lab Packs for disposal, at a cost of $4,000 to $5,000.