VII.      Disposition of Sources of Ionizing Radiation

            All sources of radiation must be strictly accounted for from the time of ordering though purchase or other mode of acquisition until departure from the direct control of the university.  Clearly, there are distinctive differences in approach to the two main types of sources, i.e., radioactive materials and radiation machines.  Hence each type will be treated separately, as will the remaining general category of other (radioactive) equipment associated with the use of sources of radiation.  All three types of source will be discussed under each foreseeable mode of disposition common to all categories.

VII.A.  Transfer

            An acceptable method of disposition of any category of materials or equipment is transfer, provided that the intended recipient is authorized to receive the materials or equipment being transferred.  If the intended recipient is at a non-Pullman location, the Radiation Safety Office will furnish advice and assistance for shipping.

VII.A.1.           Radioactive Materials

            The transfer process has been discussed as a mode of acquisition in Subsection V.B.5. above.  Clearly, the process constitutes a mode of disposition insofar as the transferor is concerned.

VII.A.2.           Radiation Machines

            The transfer of a radiation machine is feasible, along the guidelines given for transfer of radioactive materials, as a mode of disposition.  In this case, however, the Radiation Safety Office may require an exchange of documents such as the Certification of Registration of Radiation Machine Facility (issued by the State of Washington) whenever another organization is involved as the recipient.

VII.A.3.           Other (Radioactive) Equipment

            Additional devices or major items of laboratory equipment will be handled on a case-by-case basis, depending on the level of remnant activation or radioactive contamination, or both, involved.  (Items which can be completely decontaminated may be disposed of in accordance with the rules set forth in SPPM S90.81.)

VII.B.          Radioactive Waste Disposal

VII.B.1.           General

            All radioactive waste or waste materials contaminated with radioactive materials may be disposed of only in accordance with the practices and procedures established by the Radiation Safety Committee and enforced by the Radiation Safety Office.  The specific procedures, which may change with time, will include provision for handling the radioactive wastes as described below.  All disposal (and use) will be conducted in consistency with environmental monitoring requirements that are met by the Radiation Safety Office.

2.         Routine Waste Collection

            The Radiation Safety Office will routinely collect properly packaged and tagged solid and liquid materials from laboratories on campus.  It is the user's responsibility properly to tag the waste container and accurately to estimate the specific radionuclide content in the waste.

3.         Radioactive Waste Storage

            The Radiation Safety Office will accumulate and store properly tagged waste materials in an appropriate location prior to transfer to a permanent, licensed disposal site.

4.         Disposal to Sanitary Sewer System

            Authorized users on the Pullman Campus only may release to the sanitary sewer small quantities of non-alpha emitting radionuclides not to exceed the limits established in WAC 246-221-190 with the approval of the Radiation Safety Office.  In order to ensure that total university releases do not exceed the appropriate limits, individual user release limits may not exceed those listed in the table below.  (Hazardous (chemical) wastes with a radioactive component (officially labeled "Mixed wastes") are subject to additional regulatory control.  Proper disposition of these wastes must be determined by prior consultation with the Radiation Safety Office.)

(User Release Limits)


Release Limit for
One Month in Microcuries

3 H


14 C


For all other isotopes (non- 3 H, non- 14 C, and non-alpha-emitters), 83 microcuries is the limit for each isotope.

No alpha emitting isotopes may be discharged by individual authorized users.

            Authorized users must keep an accurate record of the releases to the sanitary sewer by radionuclide and report them to the Radiation Safety Office on a monthly basis, using the form in the SPPM, S90.80.8 .

VII.B.5.           Release to the Atmosphere

            Authorized users may release small quantities of radioactive gases, fumes and vapors to the atmosphere through hoods or directly in quantities not to exceed the limits established by WAC-246-221-070.  Approval for such releases is required from the Radiation Safety Office and accurate records of the quantities and types of radionuclides released must be maintained by the user and communicated to the Radiation Safety Office on a monthly basis, using the form at this link.

VII.B.6.           Radioactive Waste Incineration

            Disposal of radioactive waste by incineration is governed by extensive and rigorous regulations of the State of Washington Departments of Health and Ecology.  Incineration will be carried out at the WSU Incinerator only as planned and authorized by the Radiation Safety Office.

VII.B.7.           Radioactive Waste Packaging and Labeling

a.         General

            The Radiation Safety Office will collect and dispose of only packaged and labeled radioactive waste materials.  The following paragraphs of this section outline the basic packaging and labeling requirements.

b.         Dry Waste

            Dry waste, such as paper, gloves, and plastics, should be placed in the standard Low Specific Activity box (LSA box) which has been lined with a plastic bag.  No biological waste whatever is allowed in dry waste.  Glass pipettes, broken glass, needles and any other sharp items should be placed in a strong inner package which is placed in the larger box.  Damp material and other waste that will give off vapors or fumes should be contained in small, well-sealed plastic bags or containers before they are placed in the box.  (Animal carcasses, blood and tissue, and larger amounts [10 grams] of waste that will putrefy should be frozen and disposed of according to animal waste procedures given below.)

c.         Liquid Waste

            Liquid waste that cannot be disposed of via the sewer system must be collected and stored in an appropriate container.  Some liquid wastes may be incinerated and some must be absorbed on floor-dry and disposed of as solid waste.  The Radiation Safety Office should be consulted for more specific assistance relating to liquid waste collection.

d.         Liquid Scintillation Fluid Vials

            The waste from liquid scintillation counting deserves special mention because of both the large volume and the fire and toxic-fume hazards from some of the solvents.

(1)       When vials are reused:  The spent cocktail should be emptied into a liquid waste container and treated as liquid (mixed) waste.  Because of strong solvent fumes, this operation should be conducted in an operating fume hood.

(2)       When vials are disposed of with contents:  Liquid scintillation vials with their contents are generally disposed of by incineration.  Vials should be collected in an "egg crate" carton or packed loose in a separate LSA box.  Filled scintillation vials must not be mixed with dry waste.  The Radiation Safety Office should be consulted for more specific assistance as required,

(3)       When empty vials are disposed of:  Empty vials should be placed in a dry waste box.

e.         Animal Carcasses and Other Putrefiable Waste

            Animal carcasses and other putrefiable waste should be sealed in two layers of plastic bags, labeled as radioactive, and stored in an appropriate freezer.  The authorized user must coordinate directly with the RSO to schedule a waste pickup.  Special arrangements should be made for large carcasses and large volumes of waste.

            Certain carcasses and tissue waste may be contaminated with serious infectious and biohazardous micro-organisms.  The normal handling practices with radioactive waste do not assure protection against biological contaminants.  Special arrangements should be made to destroy the biological agents before the waste is transferred to Radiation Safety.  In some instances, such infectious radioactive waste will be disposed of by incineration.

            Carcasses and putrefiable waste must not be added to dry waste containers, nor can this type of waste be kept in the laboratory without freezing.  These boxes are stored for several weeks before final disposal.  Putrid material is extremely unpleasant.  Chronic violators of these procedures may have "ripe" waste returned to them to be properly packaged.  If not packed properly, putrid waste will not be collected.

f.          Records and Labeling

            The university license and state regulations require that inventory and control methods cover all aspects of work with radioactive material.  Therefore, all packages and containers of radioactive waste must be labeled with a radiation symbol and a description of the contents.  The label should indicate the radionuclide, the activity in microcuries (kBq) or millicuries (MBq), and the name of the authorized user.  Containers should be securely closed, both top and bottom, with strong tape or other appropriate devices.  Flaps must not be tucked one under the other; this method is not as strong as properly folded and taped flaps.  Radioactive label tape is not strong.  Both the tops and bottoms of boxes must be secured.  Plastic bags should be tied or taped closed.

            It is especially important to avoid inadvertent collection of radioactive waste by custodians.  This goal will be achieved by proper and

 prominent labeling of radioactive waste containers in the laboratory.

            As waste is being accumulated in a container, a record of each addition should be made.  The record sheet must be summarized and

must accompany the package.