requirements and to ensure that it can be handled and disposed of safely. The information needed to characterize a waste also depends on the method of ultimate disposal. (See the discussion of disposal methods in sections 8.B.6 to 8.B.7, below.)

8.B.3.4 Empty Containers

The rules for disposal of empty hazardous waste containers, and cleaning the empty containers, are complex. A container or inner liner of a container that contained hazardous waste is “empty” under federal regulations if all waste has been removed by standard practice and no more than 2.5 cm (1 in.) of residue, or 3% by weight of containers less than 110 gal, remains. If the container held acute hazardous waste, triple rinsing or equivalent measures are required before the container is “empty” within the federal regulations. The rinsate must be collected and handled as acutely hazardous waste. “Empty” containers are no longer subject to federal regulation.

These are minimum standards. If empty containers are to be recycled or disposed of in the normal trash, it is recommended that labels be removed from empty hazardous waste containers, and that they be emptied as much as possible. Consider rinsing emptied containers with water or a detergent solution. Resulting rinsate from containers previously holding acutely hazardous waste are hazardous waste and must be disposed of accordingly. Rinsate resulting from cleaning of other hazardous waste containers is hazardous waste if it exhibits EPA’s hazardous waste characteristics of ignitability, corrosivity, reactivity, or toxicity. It is prudent to follow these guidelines for disposing of empty containers of nonhazardous and nonregulated laboratory chemicals.

Properly cleaning containers as described above, and recycling or disposing of them with the normal trash, reduces costs as well as the volume of hazardous waste generated. Alternatively, some firms and institutions decide that it is more convenient to handle all empty chemical containers from laboratories as hazardous waste and dispose of them accordingly. This especially makes sense if the rinsate is hazardous.

8.B.4 Collection and Storage of Waste

8.B.4.1 Accumulation of Waste at the Location of Generation

Laboratory experiments generate a great variety of waste, including used disposable laboratory ware, filter media and similar materials, aqueous solutions, and hazardous and nonhazardous chemicals. As stated in the introduction to this chapter, begin no activity unless a plan for disposal of all waste, hazardous and nonhazardous, has been formulated.

The accumulation and temporary storage of waste in the laboratory is called satellite accumulation. The legal standards for satellite accumulation are included in this section; they are also good practices for the management of nonregulated waste. To ensure security and management oversight, chemical waste should be accumulated at or near the point of generation, and under control of laboratory personnel. Note that there is an optional alternative federal standard for the accumulation of waste within laboratories of colleges, universities, teaching hospitals, and certain nonprofit research facilities associated with colleges or universities. This is described in section 8.B.4.3, below.

Each category of waste has certain precautions and appropriate disposal methods. Below is a list of requirements and good practices for accumulating chemical waste in the laboratory:

   Collect hazardous or flammable waste solvents in an appropriate container pending transfer to the institution’s central facility or satellite site for chemical waste handling or pickup by commercial disposal firm. Often, different kinds of waste are accumulated within a common container.

   Take care not to mix incompatible waste. This is a special concern with commingled waste solvents, which must be chemically compatible to ensure that heat generation, gas evolution, or another reaction does not occur. (See the discussion of commingling in section 8.B.4.2, below.) For example, waste solvents can usually be mixed for disposal, with due regard for the compatibility of the components.

   Keep wastes segregated by how they will be managed. For example, because nonhalogenated solvents are more suitable for fuel blending, many laboratories collect halogenated and nonhalogenated solvent wastes separately.

   Collect waste in dependable containers that are compatible with their contents. Keep containers closed except when adding or subtracting waste. Separate containers of incompatible materials physically or otherwise stored in a protective manner. (See Chapter 5, section 5.E.2, for storing chemicals according to their compatibility.)

   Use an appropriate container for the collection of liquid waste. Glass bottles are impervious to most chemicals but present a breakage hazard, and narrow-neck bottles are difficult to empty. The use of plastic (e.g., polyethylene jerry cans) or metal (galvanized or stainless steel) safety containers for the collection of liquid waste is strongly encouraged. Note that flame arresters in safety

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