USPS Hazardous, Restricted and Perishable Mail.

Hazardous, Restricted and Perishable Mail

When we think of a mailman having a bad day, we usually imagine an aggressive dog at one of the delivery addresses or a long block, heavy packages, and a heat wave. We don’t usually think of severe bodily injury and hospital stays.

But the Postal Service does.

The USPS spends $101 million annually to screen every piece of first-class mail sent or received by U.S. households and mail sent to federal addresses in Washington.

With tens of thousands of postal facilities to protect, the U.S. Postal Inspection Service has responded to more than 52,000 calls about suspicious mail since 2001. Inspectors respond to about 10 calls daily. Most are false alarms.

The Postal Service now relies on both human checks and machine screenings to track suspicious mail. Shift supervisors receive regular updates on evolving threats. Postal Inspectors practice regularly with local law enforcement agencies in anticipation of an attack.

Employees are trained to be on the lookout for envelopes without a return address, an invalid Zip code, or weird or scribbled jargon. Sharp objects protruding through boxes or dust or liquids leaking from envelopes is also a potential threat. Questionable pieces of mail are supposed to be turned over to inspectors for further screening.

Hazardous, Resticted, Harmful:

To put it simply:

Some Things cannot be sent in the mail.

Those Things fall into one of the above categories: Hazardous/Harmful, Restricted, or Perishable/NonMailable Things.

If you need to send something that falls into the above categories, you need to label it properly. Ask for help to do this, because the labeling and shipping protocols are long and complicated.

If you send a Hazardous, Restricted, or Harmful Thing in the mail without following the correct protocol, you will be slapped with a very large penalty.

Hazardous Material:

A Hazardous Material is any article or substance designated by the U.S. Department of Transportation as being capable of posing an unreasonable risk to health, safety, or property during transportation.


In international commerce, hazardous materials are known as “Dangerous Goods.”


Every hazardous material is assigned to one of these nine hazard classes:


Class 1: Explosives.

Class 2: Gases.

Class 3: Flammable and Combustible Liquids.

Class 4: Flammable Solids.

Class 5: Oxidizing Substances, Organic Peroxides.

Class 6: Toxic Substances and Infectious Substances.

Class 7: Radioactive Materials.

Class 8: Corrosives.

Class 9: Miscellaneous Hazardous Materials.

Some of the nine hazard classes are further separated into divisions based on their physical or chemical properties. For postal purposes, Exhibit 331 summarizes the mailability of hazardous materials by hazard class.



If it can kill or injure another person, it is Hazardous Mail. If it is likely to destroy, deface or otherwise damage the mail, postal equipment or other property, it is Harmful Mail.

Harmful matter includes, but is not limited to:

  1. All types and classes of poisons, such as caustic poisons (acids and alkalis), and oxidizers. Controlled substances are also included in this class.
  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. All explosives, flammable material, infernal machines, and mechanical, chemical, or other devices or compositions that may ignite or explode. Highly flammable liquids, gases or solids, or any material that under conditions that take place during transportation can cause fire 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.


The following descriptions could indicate Dangerous Goods or Hazardous Materials:

Acidic, Caustic, Combustible, Communicable, Corrsoive, Explosive, Flammabe, Compressed gas, Radioactive, Poison. Toxic, Infectious, Volatile.

The USPS and UPS have an updated list of items on their websites.


Restricted Matter:


Restricted matter includes articles on which mailing restrictions have been imposed for reasons other than risk of harm to persons or property involved in moving the mail.


Motor vehicle master keys, abortive and contraceptive devices, odd-shaped items in envelopes, locksmithing devices and intoxicating liquors are examples of restricted items.


Perishable Matter:

Perishable matter is 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.

Examples of perishable matter include mailable types of live animals, food items, and plants.


The Postal Service provides these labels and tags for affixing to the outside of mailpieces containing bees, live animals, or perishable matter:

  1. Label 27, Bee Ware!
  2. Label 28, Live Animals.
  3. Tag 9, Perishable — Do Not Delay.
  4. Label 127, Surface Transportation O

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.


The USPS works with shippers wishing to mail various substances. There is a protocol in place for mailing Hazardous, Harmful, Restricted and Perishable Materials.

Acceptability for mailing hazardous materials depends on many factors, such as: “the container fluid/vapor capacities, the ability of the complete mailpiece to contain the material, and the method of absorbing and containing the material in case of accidental leakage of the primary receptacle.”

Normal conditions for transport should always be taken into consideration. All shippers who offer packages containing liquids, for example, must be trained to understand and apply the stringent standards for vibration, pressure and temperature because of the higher risk and possible dire consequences. This is especially critical when it comes to shipments by air.

To determine mailability of a specific material, a mailer must submit a material safety data sheet (MSDS) (see Appendix D) and the following information to the PCSC (see 213 for address):

  1. Common and proper shipping name of the material, hazard class, and the assigned United Nations (UN) or North American (NA) identification number.
  2. Chemical composition by percentage of weight.
  3. Flashpoint.
  4. Toxic properties.
  5. Irritant action when inhaled, swallowed, or with contact to skin or eyes.
  6. Special precautions necessary to permit handling without harm to USPS employees or damage to property or other mail.
  7. Explanation of warning labels and shipping papers required by local, state, or federal regulations.
  8. Description of the proposed packaging method, including the addressing, required markings, and documentation.
  9. Volume of material per mailpiece, proposed number of pieces to be mailed, class of mail, and post office(s) of mailing.


Full responsibility rests with the mailer to comply with all Postal Service and non–Postal Service laws and regulations in the mailing of hazardous material. Anyone who mails, or causes to be mailed, a nonmailable or improperly packaged hazardous material can be subject to legal penalties (i.e., fines and/or imprisonment), including but not limited to, those specified in 18 U.S.C. The transport of hazardous materials prior to entry as U.S. Mail and after receipt from the Postal Service is subject to DOT regulations.


Civil penalties are assessed for knowingly violating a hazardous material transportation law or a regulation, order, special permit, or approval issued under that law. The following updated civil penalties apply to violations occurring on or after October 1, 2012:

    • The maximum civil penalty is increased from $55,000 to $75,000 for knowingly violating federal hazardous material transportation law.


  • The maximum civil penalty for knowingly violating laws and regulations that result in death, serious illness, severe injury to any person, or substantial destruction of property is increased from $110,000 to $175,000.


  • The $250 minimum civil penalty has been eliminated.
  • The civil penalty for violations related to training has reverted to $450.

When someone breaks the rules, it puts us all at risk. The consequences for doing so should be substantial enough to discourage misconduct.”PHMSA administrator Cynthia Quarterman, Inc.—fined $91,000

Amazon improperly shipped a package containing flammable liquid adhesive by air via FedEx. FedEx employees discovered a gallon container of the adhesive that was leaking. The adhesive is classified as a hazardous material under the DOT regulations. Amazon offered the shipment without the requisite shipping papers or emergency response information, and did not mark, label or properly package the shipment. Amazon also failed to properly train its employees in preparing hazmat packages for shipment by air.

Alfa Chemistry—proposed fine $325,000 (still to be settled; imagine the legal costs)


Although the Postal Service makes every effort to inform its customers of the mailability of particular harmful matter via the DMM standards and the information in this and other publications, it is the responsibility of the mailer to fully meet all requirements prior to mailing. See 212 for more complete information on the responsibilities of mailers.





All the stuff you can’t mail

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