Biological agents include infectious agents of humans, plants, and animals, as well as the toxins that may be produced by microbes and by genetic material potentially hazardous by itself or when introduced into a suitable vector. The generalized “triple” packaging (primary receptacle, watertight secondary packaging, and durable outer packaging) is required for a biological agent of human disease or materials that are known or suspected of containing them. This packaging requires the “Infectious Substance” label on the outside of the package, and must be certified to meet rigorous performance tests as outlined in Federal regulations. Clinical specimens with a low probability of containing an infectious agent are also required to be "triple packaged," but performance tests require only that the package shall not leak after a four-foot drop test. Regulations on the transportation of biological agents aim to ensure that the public and the workers in the transportation chain are protected from exposure to any agent that might be in the package. Protection is achieved through the requirements for rigorous packaging that will withstand rough handling and contain all liquid material within the package without leakage to the outside. Appropriate labeling of the package is required with the biohazard symbol and other labels to alert the workers in the transportation chain to the hazardous contents of the package. Documentation of the hazardous contents of the package is required should such information be necessary in an emergency situation. Workers in the transportation chain should be trained to familiarize them with the hazardous contents enabling response to emergency situations. Biological agents and the materials that are known or suspected to contain them are recognized by Federal and State governments as hazardous materials and their transportation and transfer is subject to regulatory control. Regulations on the transfer of biological agents are aimed at ensuring that the change in possession of biological materials is within the best interests of the public and of the Nation.