The University of Iowa

SAFETYmatters - Are You Labeling Your ABSL1 rDNA Animals with the grey cage card?

Article published 03/02/18


Requirements for disposing of ABSL1 waste generated by animals that have been inoculated with rDNA or synthetic nucleic acids that are not exempt from the NIH Guidelines, requires the use of a grey cage card.  This procedure describes waste handling by research and Office of Animal Resources (OAR) staff who change cages, as specified below. 

Please note: These changes do not apply to waste generated by animals inoculated with double-stranded oligos or aptamers, since such work is exempt from the NIH Guidelines.




As a reminder, following is a summary of the requirements: 

  1. All cages/pens must be labeled to indicate that the animals they contain have been inoculated with rDNA or synthetic nucleic acids.
  2. OAR staff will coordinate the processing and disposal of waste generated from these cages/pens.
  3. Animal waste (bedding with feces and urine) must be appropriately decontaminated (see below) prior to disposal until all animals in a cage/pen are euthanized or appropriate testing has determined that the animals no longer shed the rDNA or synthetic nucleic acids with which they were inoculated.  We request that, prior to initiating any shedding studies, a proposed shedding protocol be submitted to for review by biosafety staff and members of the IBC to ensure that the experiments will effectively detect shedding.

Procedures for handling ABSL-1 waste generated by animals that have been inoculated with rDNA or synthetic nucleic acids

  1. Upon initial inoculation, cages/pens must be labeled with a grey “ABSL-1 rDNA or synthetic nucleic acid” card (which may be obtained from OAR staff).
  • Cage card includes the statement: “Waste in this cage must be disposed of in a RED BIOHAZARD BAG.  Waste must not be landfilled.”
  1. Animal cage labels must include:
  • Agent(s) in use
  • Contact name
  • Contact phone number
  1. Waste from cages labeled with a grey card must be placed in a RED BIOHAZARD BAG.
  2. If research staff wish to change the cage prior to the regular husbandry schedule, he/she may do so with the following precautions:
  • To ensure proper waste disposal, a half grey card will be placed face up in the dirty (empty) cage to inform the cage wash caretaker of possible contamination of ABSL-1 rDNA or synthetic nucleic acids in the bedding.
  • Filter tops will be placed on the cage prior to putting them with other dirty caging intended for cage washing.

Standard provisions:

  1. Reconstitution/dilution of rDNA or synthetic nucleic acids is NOT permitted in OAR facilities.
  2. Used contaminated bottles/syringes must be placed in a sharps container.

Please ensure you are following the procedures described above, as appropriate.  For a full description of the ABSL1 handling procedures, refer to EHS’s website at: