March/April 1995

Chemical Waste Forms

When filling out Chemical Waste forms, please note that more than one container can be listed on each form. You do not need a separate form for each bottle of waste.

Confusion has arisen because of differing protocols for chemical and radioactive waste. Each bottle of radioactive waste--separated by isotope--ultimately gets consolidated into an appropriate drum; each bottle, therefore, must be accompanied at all stages of the disposal process by a Waste Disposal Sheet.

However, with chemical waste this procedure is not necessary; everything can be listed on one sheet. Each item must be properly itemized. Even if the waste items are duplicates; for example, three one-gallon jugs of ethanol, they must be listed as three separate items. In addition, Hazardous Waste Tags listing chemical constituents and their respective percentages should be attached to each bottle of waste.

Please be sure to have your waste ready before you send in the pink copy of your Waste Disposal Sheet. If the waste is not fully and properly organized for disposal, we will not pick it up until the labeling is correct.

Disposal of Empty Chemical Containers

Empty chemical containers, whether glass, plastic or metal, must be properly prepared for disposal before they can be set out in the hallway for nightly pick-up.

Empty 5-gallon containers, the size usually disposed of in this manner, cannot merely be set out in the hallway after they are empty. They must first be rinsed, the lids must be removed, the labels defaced, and the word "empty" or "MT" written on them. Glass bottles must then be placed inside cardboard boxes as non contaminated sharps (see related article on sharps disposal, beginning on page 1). Empty cans or plastic containers can be set out in the hallway for pick-up only after these preparatory procedures have been done.

Housekeeping cannot pick up any containers under any other circumstances. If the proper procedures are not followed, the containers must be roped off and technicians from Safety Services must dispose of them the next day.

In order to save us from performing what is normally an unnecessary procedure, please take the time to do these simple steps. Call Safety Services at x2907 with any questions.

pH Testing: Your Liquid Waste Needs It

DOES technicians have found many liquid waste bottles that are not within acceptable pH ranges. When preparing radioactive liquid waste for disposal, test the waste's pH balance with pH paper. DOES technicians will later verify that the liquid waste is pH neutral.

Often buffers are added during an experiment to neutralize the solution, bringing its pH to a desirable level. However, it cannot be assumed that the pH will stay at that level by the time the solution is prepared for disposal. Trichloroacetic acid (TCA), for example, is a common offender; it is frequently added to experiments but very often does not get completely neutralized by the buffer. We have tested waste that is vastly out of the acceptable range because of remaining TCA.

If tissue culture media containing a pH indicator is used in your experiment, you can use the color to determine the solution's pH. Part of the media serves as an indicator; it should remain pink. If it turns yellowish-orange, the pH needs to be neutralized.

It is vital, therefore, that you check your liquid waste's pH. If it is not neutral, the waste will not be picked up or will be returned for neutralization.

Radioactive Isotope Requisition Forms

In order to process isotope request forms more efficiently, all necessary information must be present. If required information is not listed, we cannot process your request.

Each form must identify:

  • name of the Authorized User and an authorized signature for isotope purchases (the AU or an approved designee as indicated on Form 5, page 9 of the Radiation Safety Manual).
  • delivery location, room number, and phone number of the lab.
  • the vendor from which the material is being ordered.
  • the catalog number of the isotope ordered.
  • the quantity and activity, given in uCi or mCi.
  • the isotope i.e., 32P, 35S, or 3H and the chemical compound.

The Radiation Safety Office approves 3000 to 4000 requests for radioactive materials annually. Despite the large volume, we process all orders on the day they are received, provided that requisition forms arrive at our office before 4:00 pm. Requisition forms are processed in the order they arrive, and we fax them on to Purchasing as soon as possible.

Fax or mail your request forms to our office only; do not send one to Purchasing, as all orders must first be approved by our office.

The procedure is different when ordering replacement materials (see related article). If you have questions concerning how to fill out the forms or what information is needed, please feel free to call our office and ask. The information for this article was taken from pages 18 through 20 in the Radiation Safety Manual. Please refer to this section if you have further questions, or call our office and ask. Our fax number is 368-2236; our phone number is 368-2906.

Ordering Replacement Radioactive Isotopes

Occasionally there may be a problem with a radioactive material shipment that requires the vendor replace your order. Regardless of the problem, the replacement shipment must be placed through Purchasing and the Radiation Safety Office. Do not call the vendor or company directly.

If there is a problem with any radioactive isotopes received and a replacement order is needed, two procedures need to be followed:

  1. Call Charlene in Purchasing (x2560) and she will process the order--our office does not deal with vendors themselves and can only re-route your call to Purchasing.
  2. Send Purchasing a requisition form for that replacement material, just like you would for a regular order. When filling out the requisition form, write on it "Replacement" and the original requisition number of the material it is replacing. If there is no charge for the material, write "No Charge." Purchasing will then send the requisition form on to us so we have a copy of the order on file.

Again, do not call the vendor to replace your material. ALL shipments of radioactive materials must be inspected and approved by our department before Shipping and Receiving can deliver it to each lab (see chart below). The order will not arrive at a lab any sooner by calling the vendor rather than calling Purchasing and sending a requisition form. Conversely, it ends up taking much longer, since the package will be held until the order can be verified and approved.

The above procedures must be followed for replacement orders ONLY. With a regular order, simply fax or mail requisition forms to the Radiation Safety Office (see related article, page 4). We will fax them on to Purchasing as soon as possible after they have been approved, usually the same day.


Sharps, whether they are contaminated or not, cannot be disposed of in trash bags as regular waste. They must be disposed of in either the red SHARPS containers or in cardboard boxes.

All contaminated or biohazardous sharps must be disposed of in the red SHARPS container. Also, any syringes, needles, cannulas, and scalpels, whether or not they are contaminated, must be disposed of in the red SHARPS container. All other perceived sharps that are not contaminated broken glass, coverslips, pipettes, microscope slides--must be disposed of in cardboard boxes. Even if these sharps are not contaminated in any way, they cannot be placed in bags for general lab waste. Instead, lay them flat in a cardboard box so that nothing sticks out and close the container completely, taping it shut. You may wish to place the sharps in a bag first and then put the bag in the box as an extra precaution in case the box breaks. Do not overstuff these cardboard boxes or the red SHARPS containers.

Though non-biohazardous sharps do not pose a threat via contamination, they still can cause cuts or puncture wounds and are therefore dangerous to all handlers, including researchers and housekeeping staff. Housekeeping will not pick up waste designated as regular trash if they perceive that a "sharp" is present; while each specific researcher may know that his or her\ waste is uncontaminated, housekeeping staff has no way of determining this and therefore must assume for their own safety that it is contaminated.

If you have further questions about sharps disposal or other waste disposal issues, call Safety Services at x2907.

What Constitutes Liquid Waste?

As a reminder, there should be nothing solid in wastes demarcated as "liquid." Though it seems obvious, we have had problems with items like pipette tips and eppendorf tubes being present in liquid waste.

Solids cannot be mixed in with liquid waste for two reasons. First, we pour smaller bottles of liquid waste into 5-gallon containers for storage for decay. Pipette tips in the smaller waste bottles make spillage during the transfer much more likely. Secondly, after the waste has sufficiently decayed, it can be poured down the sanitary sewer. However, even if we do manage to pour eppendorf tubes into the 5-gallon storage containers, we definitely cannot manage to pour them down the sink. The sinks, as can be expected, get clogged by these and other small items.

Therefore, please be sure that nothing else is present in your liquid waste except liquid. If you have further questions on this or other disposal issues, call Radiation Safety at x2906.

Radiation Survey Documentation: What is Needed

Direct probe readings and wipe tests must be done for a radiation survey. Documentation of the survey must be recorded and kept on file so it is available for inspection by regulatory agencies.

First, probe with a survey meter the entire area where radiation was used the entire room or lab including the floors. Use of a probe is non-specific. It indicates contamination but it does not indicate the isotope nor does it indicate whether it is fixed or removable. Therefore, more specific wipe tests must be done.

Perform wipe tests using either filter papers or smears on areas such as entranceways, phones, benches, desks, floors, and hoods. Count the wipes with an appropriate counter: for beta emitters use a liquid scintillation counter, and for gamma emitters, use a gamma counter.

Documentation of the survey is imperative and must be kept on file and be available for inspection. To document a survey:

  • Mark both the places where direct probe readings and wipe tests were performed on the map of your lab or area (see sample map below).
  • Attach to the map the wipe test results and metering results.
  • Express results in terms of activity (i.e., DPM or uCi) and not CPM.
  • For areas where no contamination was found, indicate that the results are indistinguishable from background.
  • List the survey meter's make, model, serial number, and probe type.

At least one survey must be done in any month where RAM was used. If you open a container with more than 200 uCi, you must do either a post experiment survey (of the area where you worked) or a weekly survey (of the entire laboratory) NO MATTER HOW MUCH WAS ACTUALLY USED in the experiment. These surveys must include wipe tests and must be documented.

Information for this article was taken from pages 38-41 in the Radiation Safety Manual. If you have questions concerning proper documentation of your survey, check this section of the manual or call Radiation Safety (x2906).