122 Definitions

Matter is nonmailable when it does not meet the Postal Service mailability standards provided in this publication, the DMM, IMM, Postal Bulletin, and non-Postal regulations, which includes, but is not limited to, quantity, labeling and packaging, illegible, incorrect, or insufficient address, or when it does not meet Postal Service standards for mail preparation, classification, postage prices, size, or weight.

Except as provided in this publication, any article, composition, or material is nonmailable if it can kill or injure another or injure the mail or other property. Harmful matter includes, but is not limited to:

1. All types and classes of poisons, including controlled substances.
2. All poisonous animals except scorpions mailed for medical research purposes or for the manufacture of anti-venom (or antivenin or antivenene); all poisonous insects; all poisonous reptiles; and all types of snakes, turtles, and spiders.
3. All disease germs or scabs.
4. Explosives, flammable material, infernal machines, and mechanical, chemical, or other devices or compositions that may ignite or explode.

The definitions of hazardous materials, restricted matter, and perishable matter are as follows:

1. Hazardous Material (HAZMAT): Items or substances likely to harm Postal Service employees or to destroy, deface, or otherwise damage mail or postal equipment. This includes materials such as caustic poisons (acids and alkalis), oxidizers, or highly flammable liquids, gases, or solids; or materials that are likely, under conditions incident to transportation, to cause fires through friction, absorption of moisture, or spontaneous chemical changes or from retained heat from manufacturing or processing, including explosives or containers previously used for shipping high explosives with a liquid ingredient (such as dynamite), ammunition, fireworks, radioactive materials, matches, or articles emitting obnoxious odors.

Note: In international commerce, hazardous materials are referred to as "dangerous goods" (DG).

2. Restricted Matter: Articles or substances prohibited or limited by Title 18, U.S. Code (liquors, abortive and contraceptive devices, odd-shaped items in envelopes, motor vehicle master keys, and locksmithing devices). It also includes matter not otherwise described in this publication that is restricted by 18 U.S.C. § 1716(a) because it may, under conditions encountered in the mail, be injurious to life, health, or property (obnoxious odors, liquids, powders, and battery-powered devices). Restricted matter includes intoxicating liquors, firearms, construction materials, certain liquids, powders, controlled substances, hemp products, sharp objects, tobacco products, and unsolicited promotional items.
3. Perishable Matter: Anything that can deteriorate in the mail and thereby lose value, create a health hazard, or cause an obnoxious odor, nuisance, or disturbance, under ordinary mailing conditions. Mailable perishable matter may be sent at the mailer‘s own risk when it is packaged as required and when it can be delivered within appropriate and reasonable time limits to prevent deterioration. Perishable matter includes mailable dead animals, live animals, meat products, and plants.