18 USC 1716
TITLE 18 - CRIMES AND CRIMINAL PROCEDURE
PART I - CRIMES
CHAPTER 83 - POSTAL SERVICE
Sec. 1716. Injurious articles as nonmailable
(a) All kinds of poison, and all articles and compositions containing poison, and all poisonous animals, insects, reptiles, and all explosives, hazardous materials, inflammable materials, infernal machines, and mechanical, chemical, or other devices or compositions which may ignite or explode, and all disease germs or scabs, and all other natural or artificial articles, compositions, or material which may kill or injure another, or injure the mails or other property, whether or not sealed as first-class matter, are nonmailable matter and shall not be conveyed in the mails or delivered from any post office or station thereof, nor by any officer or employee of the Postal Service.
(b) The Postal Service may permit the transmission in the mails, under such rules and regulations as it shall prescribe as to preparation and packing, of any such articles which are not outwardly or of their own force dangerous or injurious to life, health, or property.
(c) The Postal Service is authorized and directed to permit the transmission in the mails, under regulations to be prescribed by it, of live scorpions which are to be used for purposes of medical research or for the manufacture of antivenom. Such regulations shall include such provisions with respect to the packaging of such live scorpions for transmission in the mails as the Postal Service deems necessary or desirable for the protection of Postal Service personnel and of the public generally and for ease of handling by such personnel and by any individual connected with such research or manufacture. Nothing contained in this paragraph shall be construed to authorize the transmission in the mails of live scorpions by means of aircraft engaged in the carriage of passengers for compensation or hire.
(d) The transmission in the mails of poisonous drugs and medicines may be limited by the Postal Service to shipments of such articles from the manufacturer thereof or dealer therein to licensed physicians, surgeons, dentists, pharmacists, druggists, cosmetologists, barbers, and veterinarians under such rules and regulations as it shall prescribe.
(e) The transmission in the mails of poisons for scientific use, and which are not outwardly dangerous or of their own force dangerous or injurious to life, health, or property, may be limited by the Postal Service to shipments of such articles between the manufacturers thereof, dealers therein, bona fide research or experimental scientific laboratories, and such other persons who are employees of the Federal, a State, or local government, whose official duties are comprised, in whole or in part, of the use of such poisons, and who are designated by the head of the agency in which they are employed to receive or send such articles, under such rules and regulations as the Postal Service shall prescribe.
(f) All spirituous, vinous, malted, fermented, or other intoxicating liquors of any kind are nonmailable and shall not be deposited in or carried through the mails.
(g) All knives having a blade which opens automatically (1) by hand pressure applied to a button or other device in the handle of the knife, or (2) by operation of inertia, gravity, or both, are nonmailable and shall not be deposited in or carried by the mails or delivered by any officer or employee of the Postal Service. Such knives may be conveyed in the mails, under such regulations as the Postal Service shall prescribe -
(1) to civilian or Armed Forces supply or procurement officers and employees of the Federal Government ordering, procuring, or purchasing such knives in connection with the activities of the Federal Government;
(2) to supply or procurement officers of the National Guard, the Air National Guard, or militia of a State ordering, procuring, or purchasing such knives in connection with the activities of such organizations;
(3) to supply or procurement officers or employees of any State, or any political subdivision of a State or Territory, ordering, procuring, or purchasing such knives in connection with the activities of such government; and
(4) to manufacturers of such knives or bona fide dealers therein in connection with any shipment made pursuant to an order from any person designated in paragraphs (1), (2), and (3). The Postal Service may require, as a condition of conveying any
such knife in the mails, that any person proposing to mail such knife explain in writing to the satisfaction of the Postal Service that the mailing of such knife will not be in violation of this section.
(h) Any advertising, promotional, or sales matter which solicits or induces the mailing of anything declared nonmailable by this section is likewise nonmailable unless such matter contains wrapping or packaging instructions which are in accord with regulations promulgated by the Postal Service.
(i)(1) Any ballistic knife shall be subject to the same restrictions and penalties provided under subsection (g) for knives described in the first sentence of that subsection.
(2) As used in this subsection, the term "ballistic knife" means a knife with a detachable blade that is propelled by a spring- operated mechanism.
(j)(1) Whoever knowingly deposits for mailing or delivery, or knowingly causes to be delivered by mail, according to the direction thereon, or at any place at which it is directed to be delivered by the person to whom it is addressed, anything declared nonmailable by this section, unless in accordance with the rules and regulations authorized to be prescribed by the Postal Service, shall be fined under this title or imprisoned not more than one year, or both.
(2) Whoever knowingly deposits for mailing or delivery, or knowingly causes to be delivered by mail, according to the direction thereon or at any place to which it is directed to be delivered by the person to whom it is addressed, anything declared nonmailable by this section, whether or not transmitted in accordance with the rules and regulations authorized to be prescribed by the Postal Service, with intent to kill or injure another, or injure the mails or other property, shall be fined under this title or imprisoned not more than twenty years, or both.
(3) Whoever is convicted of any crime prohibited by this section, which has resulted in the death of any person, shall be subject also to the death penalty or to imprisonment for life.
(k) For purposes of this section, the term "State" includes a State of the United States, the District of Columbia, and any commonwealth, territory, or possession of the United States.
Source: Office of the Law Revision Counsel, US House of Representatives, "Search the United States Code," www.uscode.house.gov (accessed Sep. 6, 2012)