A biohazard warning label would not be found on which of the following?

A biohazard warning label is typically used to indicate the presence of biological materials that pose a risk to health and safety, such as infectious agents. In the context of the given options, the presence of such labels is especially relevant for containers and receptacles that deal with potentially infectious materials.

A unit of blood released for clinical use does not require a biohazard warning label because it has already undergone screening for infectious diseases and is considered safe for transfusion purposes. Therefore, it is not classified as containing biohazardous material in the same way as the other options, which are more directly involved in handling or containing materials that are known or presumed to be infectious.

On the other hand, containers like contaminated sharps containers, refrigerators with infectious material, and receptacles for contaminated laundry are all used to manage and contain waste or materials that could be hazardous to health. These items need to be labeled appropriately to ensure that all personnel are aware of the potential risks involved when handling them.