**Item category:** Phosphorus tribromide

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN1808, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Phosphorus tribromide 8 UN1808 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Phosphorus tribromide — Postal shipping restrictions by item category


**Item category:** Phosphorus trichloride

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN1809, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Phosphorus trichloride 6.1 UN1809 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Phosphorus trichloride — Postal shipping restrictions by item category


**Item category:** Phosphorus trioxide

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN2578, packing group III; domestic mail air: 8A; domestic mail surface: 8A

> Phosphorus trioxide 8 UN2578 III 8A 8A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Phosphorus trioxide — Postal shipping restrictions by item category


**Item category:** Phosphorus trisulfide, free from yellow or white phosphorus

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.1, UN1343, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Phosphorus trisulfide, free from yellow or white phosphorus 4.1 UN1343 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Phosphorus trisulfide, free from yellow or white phosphorus — Postal shipping restrictions by item category


**Item category:** Phosphorus, white dry or Phosphorus, white, under water or Phosphorus white, in solution or Phosphorus, yellow dry or Phosphorus, yellow, under water or Phosphorus, yellow, in solution

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN1381, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Phosphorus, white dry or Phosphorus, white, under water or Phosphorus white, in solution or Phosphorus, yellow dry or Phosphorus, yellow, under water or Phosphorus, yellow, in solution 4.2 UN1381 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Phosphorus, white dry or Phosphorus, white, under water or Phosphorus white, in solution or Phosphorus, yellow dry or Phosphorus, yellow, under water or Phosphorus, yellow, in solution — Postal shipping restrictions by item category


**Item category:** Phosphorus white, molten

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN2447, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Phosphorus white, molten 4.2 UN2447 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Phosphorus white, molten — Postal shipping restrictions by item category


**Item category:** Phosphorus (white or red) and a chlorate, mixtures of

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Listed as Forbidden in the Pub 52 Appendix A mailability guide; Prohibited in domestic mail by air and by surface.

> Phosphorus (white or red) and a chlorate, mixtures of Forbidden Prohibited Prohibited Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Phosphorus (white or red) and a chlorate, mixtures of — Postal shipping restrictions by item category


**Item category:** Photographic mixtures — corrosive liquid solutions

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail via air or surface transportation

**Conditions:** Acceptable if qualifies as Limited Quantity air or surface; Packaging Instruction 8A must be followed; may be co-packed with non-hazardous dry chemicals

> Photographic Mixtures: Acceptable if the corrosive liquid solutions for preparing photographic processing mixtures can qualify as a Limited Quantity air or Limited Quantity surface material.

Source: <https://pe.usps.com/text/pub52/pub52c3_027.htm>

Photographic mixtures — corrosive liquid solutions — Postal shipping restrictions by item category


**Item category:** Phthalic anhydride with more than .05 percent maleic anhydride

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN2214, packing group III; domestic mail air: 8A; domestic mail surface: 8A

> Phthalic anhydride with more than .05 percent maleic anhydride 8 UN2214 III 8A 8A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Phthalic anhydride with more than .05 percent maleic anhydride — Postal shipping restrictions by item category


**Item category:** Picolines

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 3, UN2313, packing group III; domestic mail air: Prohibited; domestic mail surface: 3A

> Picolines 3 UN2313 III Prohibited 3A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Picolines — Postal shipping restrictions by item category


**Item category:** Pine oil

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 3, UN1272, packing group III; domestic mail air: Prohibited; domestic mail surface: 3A

> Pine oil 3 UN1272 III Prohibited 3A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Pine oil — Postal shipping restrictions by item category


**Item category:** Piperazine

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN2579, packing group III; domestic mail air: 8A; domestic mail surface: 8A

> Piperazine 8 UN2579 III 8A 8A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Piperazine — Postal shipping restrictions by item category


**Item category:** Piperidine

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN2401, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Piperidine 8 UN2401 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Piperidine — Postal shipping restrictions by item category


**Item category:** Plastic molding compound in dough, sheet, or extruded rope form evolving flammable vapor

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 9, UN3314, packing group III; domestic mail air: Prohibited; domestic mail surface: 9C

> Plastic molding compound in dough, sheet, or extruded rope form evolving flammable vapor 9 UN3314 III Prohibited 9C

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Plastic molding compound in dough, sheet, or extruded rope form evolving flammable vapor — Postal shipping restrictions by item category


**Item category:** Plastics, nitrocellulose-based, self- heating, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN2006, packing group III; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Plastics, nitrocellulose-based, self- heating, n.o.s. 4.2 UN2006 III Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Plastics, nitrocellulose-based, self- heating, n.o.s. — Postal shipping restrictions by item category


**Item category:** Poisonous drugs and medicines

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail

**Conditions:** Mailable only from manufacturers or dealers to licensed professionals (physicians, surgeons, dentists, pharmacists, etc.) per 18 U.S.C. 1716

> Poisonous Drugs and Medicines: Poisonous drugs and medicines may be sent only from manufacturers or dealers to licensed professionals, including physicians, surgeons, dentists, pharmacists, druggists, cosmetologists, barbers, and veterinarians

Source: <https://pe.usps.com/text/pub52/pub52c3_025.htm>

Poisonous drugs and medicines — Postal shipping restrictions by item category


**Item category:** Poisons

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic

**Conditions:** Some poisons may be sent by air and ground transport, others only by ground

> Some poisons may be sent by air and ground transport, others only by ground.

Source: <https://www.usps.com/ship/shipping-restrictions.htm>

Poisons — Postal shipping restrictions by item category


**Item category:** Polychlorinated biphenyls, liquid

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 9, UN2315, packing group II; domestic mail air: Prohibited; domestic mail surface: 9C

> Polychlorinated biphenyls, liquid 9 UN2315 II Prohibited 9C

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Polychlorinated biphenyls, liquid — Postal shipping restrictions by item category


**Item category:** Polychlorinated biphenyls, solid

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 9, UN3432, packing group II; domestic mail air: Prohibited; domestic mail surface: 9C

> Polychlorinated biphenyls, solid 9 UN3432 II Prohibited 9C

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Polychlorinated biphenyls, solid — Postal shipping restrictions by item category


**Item category:** Polyester resin kit

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 3, UN3269, packing group n/a; domestic mail air: Prohibited; domestic mail surface: 3A

> Polyester resin kit 3 UN3269 n/a Prohibited 3A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Polyester resin kit — Postal shipping restrictions by item category


**Item category:** Polyhalogenated biphenyls, liquid or Polyhalogenated terphenyls, liquid

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 9, UN3151, packing group II; domestic mail air: Prohibited; domestic mail surface: 9C

> Polyhalogenated biphenyls, liquid or Polyhalogenated terphenyls, liquid 9 UN3151 II Prohibited 9C

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Polyhalogenated biphenyls, liquid or Polyhalogenated terphenyls, liquid — Postal shipping restrictions by item category


**Item category:** Polyhalogenated biphenyls, solid or Polyhalogenated terphenyls, solid

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 9, UN3152, packing group II; domestic mail air: Prohibited; domestic mail surface: 9C

> Polyhalogenated biphenyls, solid or Polyhalogenated terphenyls, solid 9 UN3152 II Prohibited 9C

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Polyhalogenated biphenyls, solid or Polyhalogenated terphenyls, solid — Postal shipping restrictions by item category


**Item category:** Polymeric beads, expandable, evolving flammable vapor

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 9, UN2211, packing group III; domestic mail air: Prohibited; domestic mail surface: 9C

> Polymeric beads, expandable, evolving flammable vapor 9 UN2211 III Prohibited 9C

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Polymeric beads, expandable, evolving flammable vapor — Postal shipping restrictions by item category


**Item category:** Pool shock / chlorine tabs

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic US

**Conditions:** Classified as oxidizer. Requires hazmat declaration. $50 noncompliance fee if undeclared, effective July 12, 2026.

> Pool shock / chlorine tabs | Oxidizer | UN1748

Source: <https://selleressentials.com/usps-hazmat-noncompliance-fee-2026/>

Pool shock / chlorine tabs — Postal shipping restrictions by item category

carrier, conditions, restriction_type, scope


**Item category:** Portable chargers / power banks

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic US

**Conditions:** Standalone lithium batteries require hazmat declaration at label creation. Must carry lithium battery mark (Class 9). $50 noncompliance fee if undeclared, effective July 12, 2026.

> Portable chargers / power banks | Lithium battery (standalone) | UN3480

Source: <https://selleressentials.com/usps-hazmat-noncompliance-fee-2026/>

Portable chargers / power banks — Postal shipping restrictions by item category


**Item category:** Potassium arsenate

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN1677, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium arsenate 6.1 UN1677 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium arsenate — Postal shipping restrictions by item category


**Item category:** Potassium arsenite

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN1678, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium arsenite 6.1 UN1678 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium arsenite — Postal shipping restrictions by item category


**Item category:** Potassium borohydride

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.3, UN1870, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium borohydride 4.3 UN1870 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium borohydride — Postal shipping restrictions by item category


**Item category:** Potassium bromate

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 5.1, UN1484, packing group II; domestic mail air: 5A; domestic mail surface: 5A

> Potassium bromate 5.1 UN1484 II 5A 5A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium bromate — Postal shipping restrictions by item category


**Item category:** Potassium carbonyl

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Listed as Forbidden in the Pub 52 Appendix A mailability guide; Prohibited in domestic mail by air and by surface.

> Potassium carbonyl Forbidden Prohibited Prohibited Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium carbonyl — Postal shipping restrictions by item category


**Item category:** Potassium chlorate, aqueous solution

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 5.1, UN2427, packing group II, III; domestic mail air: 5A; domestic mail surface: 5A

> Potassium chlorate, aqueous solution 5.1 UN2427 II, III 5A 5A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium chlorate, aqueous solution — Postal shipping restrictions by item category


**Item category:** Potassium chlorate

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 5.1, UN1485, packing group II; domestic mail air: 5A; domestic mail surface: 5A

> Potassium chlorate 5.1 UN1485 II 5A 5A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium chlorate — Postal shipping restrictions by item category


**Item category:** Potassium cuprocyanide

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN1679, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium cuprocyanide 6.1 UN1679 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium cuprocyanide — Postal shipping restrictions by item category


**Item category:** Potassium cyanide, solid

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN1680, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium cyanide, solid 6.1 UN1680 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium cyanide, solid — Postal shipping restrictions by item category


**Item category:** Potassium cyanide solution

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN3413, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium cyanide solution 6.1 UN3413 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium cyanide solution — Postal shipping restrictions by item category


**Item category:** Potassium fluoride, solid

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN1812, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> Potassium fluoride, solid 6.1 UN1812 III 6A 6A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium fluoride, solid — Postal shipping restrictions by item category


**Item category:** Potassium fluoride solution

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN3422, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> Potassium fluoride solution 6.1 UN3422 III 6A 6A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium fluoride solution — Postal shipping restrictions by item category


**Item category:** Potassium fluoroacetate

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN2628, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium fluoroacetate 6.1 UN2628 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium fluoroacetate — Postal shipping restrictions by item category


**Item category:** Potassium fluorosilicate

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN2655, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> Potassium fluorosilicate 6.1 UN2655 III 6A 6A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium fluorosilicate — Postal shipping restrictions by item category


**Item category:** Potassium hydrogen sulfate

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN2509, packing group II; domestic mail air: 8A; domestic mail surface: 8A

> Potassium hydrogen sulfate 8 UN2509 II 8A 8A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium hydrogen sulfate — Postal shipping restrictions by item category


**Item category:** Potassium hydrogendifluoride, solid

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN1811, packing group II; domestic mail air: 8A; domestic mail surface: 8A

> Potassium hydrogendifluoride, solid 8 UN1811 II 8A 8A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium hydrogendifluoride, solid — Postal shipping restrictions by item category


**Item category:** Potassium hydrogendifluoride, solution

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN3421, packing group II; domestic mail air: 8A; domestic mail surface: 8A

> Potassium hydrogendifluoride, solution 8 UN3421 II 8A 8A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium hydrogendifluoride, solution — Postal shipping restrictions by item category


**Item category:** Potassium hydroxide, solid

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN1813, packing group II; domestic mail air: 8A; domestic mail surface: 8A

> Potassium hydroxide, solid 8 UN1813 II 8A 8A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium hydroxide, solid — Postal shipping restrictions by item category


**Item category:** Potassium hydroxide, solution

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN1814, packing group II, III; domestic mail air: 8A; domestic mail surface: 8A

> Potassium hydroxide, solution 8 UN1814 II, III 8A 8A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium hydroxide, solution — Postal shipping restrictions by item category


**Item category:** Potassium, metal alloys, liquid

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 4.3, UN1420, packing group I; domestic mail air: Prohibited; domestic mail surface: 4A

> Potassium, metal alloys, liquid 4.3 UN1420 I Prohibited 4A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium, metal alloys, liquid — Postal shipping restrictions by item category


**Item category:** Potassium, metal alloys, solid

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.3, UN3403, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium, metal alloys, solid 4.3 UN3403 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium, metal alloys, solid — Postal shipping restrictions by item category


**Item category:** Potassium metavanadate

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN2864, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium metavanadate 6.1 UN2864 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium metavanadate — Postal shipping restrictions by item category


**Item category:** Potassium monoxide

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN2033, packing group II; domestic mail air: 8A; domestic mail surface: 8A

> Potassium monoxide 8 UN2033 II 8A 8A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium monoxide — Postal shipping restrictions by item category


**Item category:** Potassium nitrate and sodium nitrite mixtures

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 5.1, UN1487, packing group II; domestic mail air: 5A; domestic mail surface: 5A

> Potassium nitrate and sodium nitrite mixtures 5.1 UN1487 II 5A 5A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium nitrate and sodium nitrite mixtures — Postal shipping restrictions by item category


**Item category:** Potassium nitrate

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 5.1, UN1486, packing group III; domestic mail air: 5A; domestic mail surface: 5A

> Potassium nitrate 5.1 UN1486 III 5A 5A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium nitrate — Postal shipping restrictions by item category


**Item category:** Potassium nitrite

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 5.1, UN1488, packing group II; domestic mail air: 5A; domestic mail surface: 5A

> Potassium nitrite 5.1 UN1488 II 5A 5A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium nitrite — Postal shipping restrictions by item category


**Item category:** Potassium perchlorate

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 5.1, UN1489, packing group II; domestic mail air: 5A; domestic mail surface: 5A

> Potassium perchlorate 5.1 UN1489 II 5A 5A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium perchlorate — Postal shipping restrictions by item category


**Item category:** Potassium permanganate

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 5.1, UN1490, packing group II; domestic mail air: 5A; domestic mail surface: 5A

> Potassium permanganate 5.1 UN1490 II 5A 5A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium permanganate — Postal shipping restrictions by item category


**Item category:** Potassium peroxide

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 5.1, UN1491, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium peroxide 5.1 UN1491 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium peroxide — Postal shipping restrictions by item category


**Item category:** Potassium peroxide

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** all mail

**Conditions:** Nonmailable Division 5.1 oxidizing substance

> Potassium peroxide.

Source: <https://pe.usps.com/text/pub52/pub52c3_024.htm>


**Item category:** Potassium persulfate

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 5.1, UN1492, packing group III; domestic mail air: 5A; domestic mail surface: 5A

> Potassium persulfate 5.1 UN1492 III 5A 5A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium persulfate — Postal shipping restrictions by item category


**Item category:** Potassium phosphide

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.3, UN2012, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium phosphide 4.3 UN2012 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium phosphide — Postal shipping restrictions by item category


**Item category:** Potassium sodium alloys, liquid

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.3, UN1422, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium sodium alloys, liquid 4.3 UN1422 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium sodium alloys, liquid — Postal shipping restrictions by item category


**Item category:** Potassium sodium alloys, solid

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.3, UN3404, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium sodium alloys, solid 4.3 UN3404 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium sodium alloys, solid — Postal shipping restrictions by item category


**Item category:** Potassium sulfide, anhydrous or Potassium sulfide with less than 30 percent water of crystallization

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN1382, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium sulfide, anhydrous or Potassium sulfide with less than 30 percent water of crystallization 4.2 UN1382 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium sulfide, anhydrous or Potassium sulfide with less than 30 percent water of crystallization — Postal shipping restrictions by item category


**Item category:** Potassium sulfide, hydrated with not less than 30 percent water of crystallization

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN1847, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium sulfide, hydrated with not less than 30 percent water of crystallization 8 UN1847 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium sulfide, hydrated with not less than 30 percent water of crystallization — Postal shipping restrictions by item category


**Item category:** Potassium superoxide

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 5.1, UN2466, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium superoxide 5.1 UN2466 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium superoxide — Postal shipping restrictions by item category


**Item category:** Potassium

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.3, UN2257, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Potassium 4.3 UN2257 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Potassium — Postal shipping restrictions by item category


**Item category:** Powder cake, wetted or Powder paste, wetted with not less than 17 percent alcohol by mass

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.1C, UN0433, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Powder cake, wetted or Powder paste, wetted with not less than 17 percent alcohol by mass 1.1C UN0433 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Powder cake, wetted or Powder paste, wetted with not less than 17 percent alcohol by mass — Postal shipping restrictions by item category


**Item category:** Powder cake, wetted or Powder paste, wetted with not less than 25 percent water, by mass

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.3C, UN0159, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Powder cake, wetted or Powder paste, wetted with not less than 25 percent water, by mass 1.3C UN0159 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Powder cake, wetted or Powder paste, wetted with not less than 25 percent water, by mass — Postal shipping restrictions by item category


**Item category:** Powder, smokeless

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.3C, UN0161, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Powder, smokeless 1.3C UN0161 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Powder, smokeless — Postal shipping restrictions by item category


**Item category:** powders - dry materials that could cause damage

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** all domestic mail

**Conditions:** Powders must be packed in sift-proof containers or other containers that are sealed in durable sift-proof outer containers

> Powders must be packed in sift-proof containers or other containers that are sealed in durable sift-proof outer containers.

Source: <https://pe.usps.com/text/pub52/pub52c4_018.htm>

powders - dry materials that could cause damage — Postal shipping restrictions by item category


**Item category:** prescription medications containing controlled substances

**Carrier:** USPS

**Restriction type:** allowed

**Scope:** domestic mail - from authorized dispensers

**Conditions:** Prescription medicines containing mailable narcotic drugs (controlled substances) may be mailed only by drug manufacturers or their registered agents, pharmacies, medical practitioners, or other authorized dispensers, as permitted by 21 CFR Section 1307.11

> Prescription medicines containing mailable narcotic drugs (controlled substances), when mailed by drug manufacturers or their registered agents, pharmacies, medical practitioners, or other authorized dispensers

Source: <https://pe.usps.com/text/pub52/pub52c4_020.htm>

prescription medications containing controlled substances — Postal shipping restrictions by item category

carrier, conditions, item_category, restriction_type


**Item category:** Primers, cap type

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.1B, UN0377, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Primers, cap type 1.1B UN0377 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Primers, cap type — Postal shipping restrictions by item category


**Item category:** Primers, tubular

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.3G, UN0319, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Primers, tubular 1.3G UN0319 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Primers, tubular — Postal shipping restrictions by item category


**Item category:** Printing ink, flammable or Printing ink related material (including printing ink thinning or reducing compound), flammable

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 3, UN1210, packing group I, II,; domestic mail air: Prohibited; domestic mail surface: 3A

> Printing ink, flammable or Printing ink related material (including printing ink thinning or reducing compound), flammable 3 UN1210 I, II, II Prohibited 3A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Printing ink, flammable or Printing ink related material (including printing ink thinning or reducing compound), flammable — Postal shipping restrictions by item category


**Item category:** Prohibited Prohibited Prohibited Prohibited Prohibited Nickel carbonyl

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN1259, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Prohibited Prohibited Prohibited Prohibited Prohibited Nickel carbonyl 6.1 UN1259 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Prohibited Prohibited Prohibited Prohibited Prohibited Nickel carbonyl — Postal shipping restrictions by item category


**Item category:** Projectiles, inert with tracer

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.4G, UN0425, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Projectiles, inert with tracer 1.4G UN0425 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Projectiles, inert with tracer — Postal shipping restrictions by item category


**Item category:** Projectiles, with burster or expelling charge

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.2D, UN0346, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Projectiles, with burster or expelling charge 1.2D UN0346 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Projectiles, with burster or expelling charge — Postal shipping restrictions by item category


**Item category:** Projectiles, with bursting charge

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.1D, UN0168, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Projectiles, with bursting charge 1.1D UN0168 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Projectiles, with bursting charge — Postal shipping restrictions by item category


**Item category:** Propadiene, stabilized

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 2.1, UN2200, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Propadiene, stabilized 2.1 UN2200 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propadiene, stabilized — Postal shipping restrictions by item category


**Item category:** Propane — Division 2.1 flammable gas

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail via surface transportation only

**Conditions:** Mailable via surface transportation as Limited Quantity material only; air transportation is prohibited

> Propane: Division 2.1 flammable gas. Propane is mailable via surface transportation as a Limited Quantity material only. Air transportation is prohibited.

Source: <https://pe.usps.com/text/pub52/pub52c3_021.htm>

Propane — Division 2.1 flammable gas — Postal shipping restrictions by item category


**Item category:** Propanethiols

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 3, UN2402, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Propanethiols 3 UN2402 II Prohibited 3A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propanethiols — Postal shipping restrictions by item category


**Item category:** Propellant, liquid

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.1C, UN0497, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Propellant, liquid 1.1C UN0497 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propellant, liquid — Postal shipping restrictions by item category


**Item category:** Propellant, solid

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.1C, UN0498, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Propellant, solid 1.1C UN0498 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propellant, solid — Postal shipping restrictions by item category


**Item category:** Properly declared hazardous packages (USPS HazMat Handling Fee)

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** Priority Mail Express, Priority Mail, Ground Advantage, Parcel Select (from July 12, 2026)

**Conditions:** A HazMat Handling Fee applies to properly declared hazardous packages: $7.50 each on Priority Mail Express and Priority Mail, and $0 initially on USPS Ground Advantage and Parcel Select; the $50 noncompliance fee applies per package when hazmat is detected undeclared.

> A companion fee — the HazMat Handling Fee — also applies to properly declared hazardous packages: $7.50 each on Priority Mail Express and Priority Mail, and $0 initially on USPS Ground Advantage and Parcel Select, with the option for USPS to raise the ground-class fee in the future.

Source: <https://selleressentials.com/usps-hazmat-noncompliance-fee-2026/>

Properly declared hazardous packages (USPS HazMat Handling Fee) — Postal shipping restrictions by item category


**Item category:** Propionaldehyde

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 3, UN1275, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Propionaldehyde 3 UN1275 II Prohibited 3A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propionaldehyde — Postal shipping restrictions by item category


**Item category:** Propionic acid with not less than 10 percent and less than 90 percent acid by mass

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN1848, packing group III; domestic mail air: 8A; domestic mail surface: 8A

> Propionic acid with not less than 10 percent and less than 90 percent acid by mass 8 UN1848 III 8A 8A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propionic acid with not less than 10 percent and less than 90 percent acid by mass — Postal shipping restrictions by item category


**Item category:** Propionic acid with not less than 90 percent acid by mass

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 8, UN3463, packing group II; domestic mail air: Prohibited; domestic mail surface: 8A

> Propionic acid with not less than 90 percent acid by mass 8 UN3463 II Prohibited 8A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propionic acid with not less than 90 percent acid by mass — Postal shipping restrictions by item category


**Item category:** Propionic anhydride

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN2496, packing group III; domestic mail air: 8A; domestic mail surface: 8A

> Propionic anhydride 8 UN2496 III 8A 8A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propionic anhydride — Postal shipping restrictions by item category


**Item category:** Propionitrile

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 3, UN2404, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Propionitrile 3 UN2404 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propionitrile — Postal shipping restrictions by item category


**Item category:** Propionyl chloride

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 3, UN1815, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Propionyl chloride 3 UN1815 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propionyl chloride — Postal shipping restrictions by item category


**Item category:** Propyl formates

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 3, UN1281, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Propyl formates 3 UN1281 II Prohibited 3A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propyl formates — Postal shipping restrictions by item category


**Item category:** Propylamine

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 3, UN1277, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Propylamine 3 UN1277 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propylamine — Postal shipping restrictions by item category


**Item category:** Propylene chlorohydrin

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN2611, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Propylene chlorohydrin 6.1 UN2611 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propylene chlorohydrin — Postal shipping restrictions by item category


**Item category:** Propylene oxide

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 3, UN1280, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Propylene oxide 3 UN1280 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propylene oxide — Postal shipping restrictions by item category


**Item category:** Propylene tetramer

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 3, UN2850, packing group III; domestic mail air: Prohibited; domestic mail surface: 3A

> Propylene tetramer 3 UN2850 III Prohibited 3A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propylene tetramer — Postal shipping restrictions by item category


**Item category:** Propyleneimine, stabilized

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 3, UN1921, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Propyleneimine, stabilized 3 UN1921 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propyleneimine, stabilized — Postal shipping restrictions by item category


**Item category:** Propyltrichlorosilane

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN1816, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Propyltrichlorosilane 8 UN1816 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Propyltrichlorosilane — Postal shipping restrictions by item category


**Item category:** Pyrethroid pesticide, liquid, flammable, toxic, flashpoint less than 23° C

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN3351, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Pyrethroid pesticide, liquid, flammable, toxic, flashpoint less than 23° C 6.1 UN3351 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Pyrethroid pesticide, liquid, flammable, toxic, flashpoint less than 23° C — Postal shipping restrictions by item category


**Item category:** Pyrethroid pesticide, liquid, toxic

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN3352, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Pyrethroid pesticide, liquid, toxic 6.1 UN3352 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Pyrethroid pesticide, liquid, toxic — Postal shipping restrictions by item category


**Item category:** Pyrethroid pesticide, solid, toxic

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN3349, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Pyrethroid pesticide, solid, toxic 6.1 UN3349 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Pyrethroid pesticide, solid, toxic — Postal shipping restrictions by item category


**Item category:** Pyridine perchlorate

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Listed as Forbidden in the Pub 52 Appendix A mailability guide; Prohibited in domestic mail by air and by surface.

> Pyridine perchlorate Forbidden Prohibited Prohibited Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Pyridine perchlorate — Postal shipping restrictions by item category


**Item category:** Pyridine

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 3, UN1282, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Pyridine 3 UN1282 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Pyridine — Postal shipping restrictions by item category


**Item category:** Pyrophoric liquid, inorganic, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN3194, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Pyrophoric liquid, inorganic, n.o.s. 4.2 UN3194 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Pyrophoric liquid, inorganic, n.o.s. — Postal shipping restrictions by item category


**Item category:** Pyrophoric liquids, organic, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN2845, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Pyrophoric liquids, organic, n.o.s. 4.2 UN2845 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Pyrophoric liquids, organic, n.o.s. — Postal shipping restrictions by item category


**Item category:** Pyrophoric metals, n.o.s. or Pyrophoric alloys, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN1383, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Pyrophoric metals, n.o.s. or Pyrophoric alloys, n.o.s. 4.2 UN1383 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Pyrophoric metals, n.o.s. or Pyrophoric alloys, n.o.s. — Postal shipping restrictions by item category


**Item category:** Pyrophoric solid, inorganic, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN3200, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Pyrophoric solid, inorganic, n.o.s. 4.2 UN3200 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Pyrophoric solid, inorganic, n.o.s. — Postal shipping restrictions by item category


**Item category:** Pyrophoric solids, organic, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN2846, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Pyrophoric solids, organic, n.o.s. 4.2 UN2846 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Pyrophoric solids, organic, n.o.s. — Postal shipping restrictions by item category


**Item category:** Pyrosulfuryl chloride

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN1817, packing group II; domestic mail air: 8A; domestic mail surface: 8A

> Pyrosulfuryl chloride 8 UN1817 II 8A 8A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Pyrosulfuryl chloride — Postal shipping restrictions by item category


**Item category:** Pyrrolidine

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 3, UN1922, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Pyrrolidine 3 UN1922 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Pyrrolidine — Postal shipping restrictions by item category


**Item category:** Quebrachitol pentanitrate

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Listed as Forbidden in the Pub 52 Appendix A mailability guide; Prohibited in domestic mail by air and by surface.

> Quebrachitol pentanitrate Forbidden Prohibited Prohibited Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Quebrachitol pentanitrate — Postal shipping restrictions by item category


**Item category:** queen honeybees

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail - air or surface transportation

**Conditions:** May be shipped via air or surface transportation; each mailpiece shipped via air is limited to one queen and eight or fewer attendant honeybees; must be plainly marked 'Live Queen Bees'

> Queen Honeybees: May be shipped via air or surface transportation. Each mailpiece shipped via air transportation is limited to one queen and eight or less attendant honeybees.

Source: <https://pe.usps.com/text/pub52/pub52c5_009.htm>

queen honeybees — Postal shipping restrictions by item category


**Item category:** Quinoline

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN2656, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> Quinoline 6.1 UN2656 III 6A 6A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Quinoline — Postal shipping restrictions by item category


**Item category:** R 125

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 2.2, UN3220, packing group n/a; domestic mail air: 2B; domestic mail surface: 2B

> R 125 2.2 UN3220 n/a 2B 2B

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

R 125 — Postal shipping restrictions by item category


**Item category:** Radioactive instruments and articles (UN2911) — clocks, electronic tubes

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail via surface transportation

**Conditions:** Mailable if activity does not exceed limits in Exhibit 347.22; classified as excepted package for simplified handling per 49 CFR 172.101; must follow Packaging Instruction 7A

> UN2911: Low-risk items like clocks, electronic tubes, or similar devices with radioactive materials in gas or solid form, classified as "excepted package" for simplified handling under 49 CFR § 172.101.

Source: <https://pe.usps.com/text/pub52/pub52c3_026.htm>

Radioactive instruments and articles (UN2911) — clocks, electronic tubes — Postal shipping restrictions by item category


**Item category:** Radioactive material, excepted package-empty packaging

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN2908, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, excepted package-empty packaging 7 UN2908 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, excepted package-empty packaging — Postal shipping restrictions by item category


**Item category:** Radioactive material, excepted package-instruments or articles

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 7, UN2911, packing group n/a; domestic mail air: Prohibited; domestic mail surface: 7A

> Radioactive material, excepted package-instruments or articles 7 UN2911 n/a Prohibited 7A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, excepted package-instruments or articles — Postal shipping restrictions by item category


**Item category:** Radioactive material, excepted package-limited quantity of material

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 7, UN2910, packing group n/a; domestic mail air: Prohibited; domestic mail surface: 7A

> Radioactive material, excepted package-limited quantity of material 7 UN2910 n/a Prohibited 7A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, excepted package-limited quantity of material — Postal shipping restrictions by item category


**Item category:** Radioactive material, low specific activity (LSA-I), non fissile or fissile- excepted.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN2912, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, low specific activity (LSA-I), non fissile or fissile- excepted. 7 UN2912 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, low specific activity (LSA-I), non fissile or fissile- excepted. — Postal shipping restrictions by item category


**Item category:** Radioactive material, low specific activity (LSA-II), non fissile or fissile- excepted.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN3321, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, low specific activity (LSA-II), non fissile or fissile- excepted. 7 UN3321 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, low specific activity (LSA-II), non fissile or fissile- excepted. — Postal shipping restrictions by item category


**Item category:** Radioactive material, low specific activity (LSA-III), non fissile or fissile- excepted.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN3322, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, low specific activity (LSA-III), non fissile or fissile- excepted. 7 UN3322 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, low specific activity (LSA-III), non fissile or fissile- excepted. — Postal shipping restrictions by item category


**Item category:** Radioactive material, surface contaminated objects (SCO-I or SCO-II) non fissile or fissile- excepted

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN2913, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, surface contaminated objects (SCO-I or SCO-II) non fissile or fissile- excepted 7 UN2913 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, surface contaminated objects (SCO-I or SCO-II) non fissile or fissile- excepted — Postal shipping restrictions by item category


**Item category:** Radioactive material, transported under special arrangement, fissile

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN3331, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, transported under special arrangement, fissile 7 UN3331 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, transported under special arrangement, fissile — Postal shipping restrictions by item category


**Item category:** Radioactive material, transported under special arrangement, non fissile or fissile excepted

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN2919, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, transported under special arrangement, non fissile or fissile excepted 7 UN2919 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, transported under special arrangement, non fissile or fissile excepted — Postal shipping restrictions by item category


**Item category:** Radioactive material, Type A package, fissile non-special form, non fissile or fissile-excepted

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN2915, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, Type A package, fissile non-special form, non fissile or fissile-excepted 7 UN2915 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, Type A package, fissile non-special form, non fissile or fissile-excepted — Postal shipping restrictions by item category


**Item category:** Radioactive material, Type A package, fissile non-special form

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN3327, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, Type A package, fissile non-special form 7 UN3327 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, Type A package, fissile non-special form — Postal shipping restrictions by item category


**Item category:** Radioactive material, Type A package, non fissile or fissile- excepted

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN3332, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, Type A package, non fissile or fissile- excepted 7 UN3332 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, Type A package, non fissile or fissile- excepted — Postal shipping restrictions by item category


**Item category:** Radioactive material, Type A package, special form, fissile

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN3333, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, Type A package, special form, fissile 7 UN3333 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, Type A package, special form, fissile — Postal shipping restrictions by item category


**Item category:** Radioactive material, Type B(M) package, fissile

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN3329, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, Type B(M) package, fissile 7 UN3329 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, Type B(M) package, fissile — Postal shipping restrictions by item category


**Item category:** Radioactive material, Type B(M) package non fissile or fissile- excepted

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN2917, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, Type B(M) package non fissile or fissile- excepted 7 UN2917 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, Type B(M) package non fissile or fissile- excepted — Postal shipping restrictions by item category


**Item category:** Radioactive material, Type B(U) package, fissile

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN3328, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, Type B(U) package, fissile 7 UN3328 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, Type B(U) package, fissile — Postal shipping restrictions by item category


**Item category:** Radioactive material, Type B(U) package non fissile or fissile- excepted

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN2916, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, Type B(U) package non fissile or fissile- excepted 7 UN2916 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, Type B(U) package non fissile or fissile- excepted — Postal shipping restrictions by item category


**Item category:** Radioactive material, uranium hexafluoride fissile

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN2977, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, uranium hexafluoride fissile 7 UN2977 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, uranium hexafluoride fissile — Postal shipping restrictions by item category


**Item category:** Radioactive material, uranium hexafluoride non fissile or fissile- excepted

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 7, UN2978, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Radioactive material, uranium hexafluoride non fissile or fissile- excepted 7 UN2978 n/a Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Radioactive material, uranium hexafluoride non fissile or fissile- excepted — Postal shipping restrictions by item category


**Item category:** Radioactive materials bearing Class 7 labels — international mail

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** international mail

**Conditions:** Radioactive materials bearing or required to bear a Class 7 Radioactive White-I, Yellow-II, or Yellow-III label are prohibited; eligible shipments may only go via First-Class Package International Service with Registered Mail

> International Mail: Radioactive materials bearing or required to bear a Class 7 Radioactive White-I, Radioactive Yellow-II, or Radioactive Yellow-III hazardous materials warning label

Source: <https://pe.usps.com/text/pub52/pub52c3_026.htm>

Radioactive materials bearing Class 7 labels — international mail — Postal shipping restrictions by item category


**Item category:** Radioactive materials bearing Class 7 labels or Fissile label — domestic surface

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail via surface transportation

**Conditions:** Radioactive materials bearing or required to bear Radioactive White-I, Yellow-II, Yellow-III, or Fissile label are prohibited from domestic surface mail

> Domestic Mail via Surface Transportation: Radioactive materials bearing or required to bear a Class 7 Radioactive White-I, Radioactive Yellow-II, Radioactive Yellow-III hazardous materials warning label, or the Fissile label

Source: <https://pe.usps.com/text/pub52/pub52c3_026.htm>

Radioactive materials bearing Class 7 labels or Fissile label — domestic surface — Postal shipping restrictions by item category


**Item category:** Radioactive materials (Hazard Class 7) — domestic air

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail via air transportation

**Conditions:** All radioactive materials are prohibited from domestic air mail

> Domestic Mail via Air Transportation: All radioactive materials are prohibited.

Source: <https://pe.usps.com/text/pub52/pub52c3_026.htm>

Radioactive materials (Hazard Class 7) — domestic air — Postal shipping restrictions by item category


**Item category:** Rags, oily

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN1856, packing group III; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Rags, oily 4.2 UN1856 III Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Rags, oily — Postal shipping restrictions by item category


**Item category:** Receptacles, small, containing gas or gas cartridges (nonflammable) without release device, not refillable and not exceeding 1 L capacity

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 2.2, UN2037, packing group n/a; domestic mail air: 2B; domestic mail surface: 2B

> Receptacles, small, containing gas or gas cartridges (nonflammable) without release device, not refillable and not exceeding 1 L capacity 2.2 UN2037 n/a 2B 2B

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Receptacles, small, containing gas or gas cartridges (nonflammable) without release device, not refillable and not exceeding 1 L capacity — Postal shipping restrictions by item category


**Item category:** Receptacles, small, containing gas or gas cartridges (oxidizing) without release device, not refillable and not exceeding 1 L capacity

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 2.2, UN2037, packing group n/a; domestic mail air: Prohibited; domestic mail surface: 2B

> Receptacles, small, containing gas or gas cartridges (oxidizing) without release device, not refillable and not exceeding 1 L capacity 2.2 UN2037 n/a Prohibited 2B

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Receptacles, small, containing gas or gas cartridges (oxidizing) without release device, not refillable and not exceeding 1 L capacity — Postal shipping restrictions by item category


**Item category:** Refrigerant gas R 404A

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 2.2, UN3337, packing group n/a; domestic mail air: 2B; domestic mail surface: 2B

> Refrigerant gas R 404A 2.2 UN3337 n/a 2B 2B

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Refrigerant gas R 404A — Postal shipping restrictions by item category


**Item category:** Refrigerant gas R 407A

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 2.2, UN3338, packing group n/a; domestic mail air: 2B; domestic mail surface: 2B

> Refrigerant gas R 407A 2.2 UN3338 n/a 2B 2B

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Refrigerant gas R 407A — Postal shipping restrictions by item category


**Item category:** Refrigerant gas R 407B

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 2.2, UN3339, packing group n/a; domestic mail air: 2B; domestic mail surface: 2B

> Refrigerant gas R 407B 2.2 UN3339 n/a 2B 2B

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Refrigerant gas R 407B — Postal shipping restrictions by item category


**Item category:** Refrigerant gas R 407C

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 2.2, UN3340, packing group n/a; domestic mail air: 2B; domestic mail surface: 2B

> Refrigerant gas R 407C 2.2 UN3340 n/a 2B 2B

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Refrigerant gas R 407C — Postal shipping restrictions by item category


**Item category:** Refrigerant gases, n.o.s., or Dispersant gases, n.o.s.

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 2.1, NA1954, packing group n/a; domestic mail air: Prohibited; domestic mail surface: 2A

> Refrigerant gases, n.o.s., or Dispersant gases, n.o.s. 2.1 NA1954 n/a Prohibited 2A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Refrigerant gases, n.o.s., or Dispersant gases, n.o.s. — Postal shipping restrictions by item category


**Item category:** Refrigerant gases, n.o.s.

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 2.2, UN1078, packing group n/a; domestic mail air: 2B; domestic mail surface: 2B

> Refrigerant gases, n.o.s. 2.2 UN1078 n/a 2B 2B

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Refrigerant gases, n.o.s. — Postal shipping restrictions by item category


**Item category:** Refrigerating machines, containing flammable, non-toxic, liquified gas

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 2.1, UN3358, packing group n/a; domestic mail air: Prohibited; domestic mail surface: 2A

> Refrigerating machines, containing flammable, non-toxic, liquified gas 2.1 UN3358 n/a Prohibited 2A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Refrigerating machines, containing flammable, non-toxic, liquified gas — Postal shipping restrictions by item category


**Item category:** Refrigerating machines, containing non-flammable, non-toxic, or ammonia solution (UN2672)

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 2.2, UN2857, packing group n/a; domestic mail air: 2B; domestic mail surface: 2B

> Refrigerating machines, containing non-flammable, non-toxic, or ammonia solution (UN2672) 2.2 UN2857 n/a 2B 2B

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Refrigerating machines, containing non-flammable, non-toxic, or ammonia solution (UN2672) — Postal shipping restrictions by item category


**Item category:** Regulated magnetized materials — international mail

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** international mail

**Conditions:** Regulated magnetized materials are prohibited from international mail; only non-regulated materials with field strength below 0.002 gauss at 7 feet may be mailed internationally

> International Mail: Only non-regulated magnetized materials with a magnetic field strength below 0.002 gauss at a distance of 7 feet may be mailed internationally. Regulated magnetized materials are prohibited

Source: <https://pe.usps.com/text/pub52/pub52c3_028.htm>

Regulated magnetized materials — international mail — Postal shipping restrictions by item category


**Item category:** Regulated medical waste (nonsharps), n.o.s. or Clinical waste, unspecified, n.o.s. or (BIO) Medical waste, n.o.s. or Biomedical waste, n.o.s. or Medical waste, n.o.s.

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 6.2, UN3291, packing group II; domestic mail air: Prohibited; domestic mail surface: 6E

> Regulated medical waste (nonsharps), n.o.s. or Clinical waste, unspecified, n.o.s. or (BIO) Medical waste, n.o.s. or Biomedical waste, n.o.s. or Medical waste, n.o.s. 6.2 UN3291 II Prohibited 6E

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Regulated medical waste (nonsharps), n.o.s. or Clinical waste, unspecified, n.o.s. or (BIO) Medical waste, n.o.s. or Biomedical waste, n.o.s. or Medical waste, n.o.s. — Postal shipping restrictions by item category


**Item category:** Regulated medical waste (sharps), n.o.s. or Clinical waste, unspecified, n.o.s. or (BIO) Medical waste, n.o.s. or Biomedical waste, n.o.s. or Medical waste, n.o.s.

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 6.2, UN3291, packing group II; domestic mail air: Prohibited; domestic mail surface: 6D

> Regulated medical waste (sharps), n.o.s. or Clinical waste, unspecified, n.o.s. or (BIO) Medical waste, n.o.s. or Biomedical waste, n.o.s. or Medical waste, n.o.s. 6.2 UN3291 II Prohibited 6D

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Regulated medical waste (sharps), n.o.s. or Clinical waste, unspecified, n.o.s. or (BIO) Medical waste, n.o.s. or Biomedical waste, n.o.s. or Medical waste, n.o.s. — Postal shipping restrictions by item category


**Item category:** Release devices, explosive

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.4S, UN0173, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Release devices, explosive 1.4S UN0173 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Release devices, explosive — Postal shipping restrictions by item category


**Item category:** Resin solution, flammable

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 3, UN1866, packing group I, II, III; domestic mail air: Prohibited; domestic mail surface: 3A

> Resin solution, flammable 3 UN1866 I, II, III Prohibited 3A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Resin solution, flammable — Postal shipping restrictions by item category


**Item category:** Resorcinol

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN2876, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> Resorcinol 6.1 UN2876 III 6A 6A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Resorcinol — Postal shipping restrictions by item category


**Item category:** rifles and shotguns - unloaded, intrastate

**Carrier:** USPS

**Restriction type:** allowed

**Scope:** domestic mail - intrastate shipments

**Conditions:** Subject to state regulations; mailpiece must display Return Service Requested endorsement and be shipped using tracking and signature capture service

> unloaded rifles and shotguns are mailable. Mailers must comply with the rules and regulations per 27 CFR, Part 478, as well as state and local laws.

Source: <https://pe.usps.com/text/pub52/pub52c4_010.htm>

rifles and shotguns - unloaded, intrastate — Postal shipping restrictions by item category


**Item category:** Rivets, explosive

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.4S, UN0174, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Rivets, explosive 1.4S UN0174 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Rivets, explosive — Postal shipping restrictions by item category


**Item category:** Rocket motors, liquid fueled

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.2J, UN0395, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Rocket motors, liquid fueled 1.2J UN0395 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Rocket motors, liquid fueled — Postal shipping restrictions by item category


**Item category:** Rocket motors with hypergolic liquids with or without an expelling charge

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.3L, UN0250, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Rocket motors with hypergolic liquids with or without an expelling charge 1.3L UN0250 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Rocket motors with hypergolic liquids with or without an expelling charge — Postal shipping restrictions by item category


**Item category:** Rocket motors

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.1C, UN0280, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Rocket motors 1.1C UN0280 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Rocket motors — Postal shipping restrictions by item category


**Item category:** Rockets, line-throwing

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.2G, UN0238, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Rockets, line-throwing 1.2G UN0238 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Rockets, line-throwing — Postal shipping restrictions by item category


**Item category:** Rockets, liquid fueled with bursting charge

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.1J, UN0397, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Rockets, liquid fueled with bursting charge 1.1J UN0397 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Rockets, liquid fueled with bursting charge — Postal shipping restrictions by item category


**Item category:** Rockets, with bursting charge

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.1E, UN0181, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Rockets, with bursting charge 1.1E UN0181 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Rockets, with bursting charge — Postal shipping restrictions by item category


**Item category:** Rockets, with expelling charge

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.2C, UN0436, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Rockets, with expelling charge 1.2C UN0436 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Rockets, with expelling charge — Postal shipping restrictions by item category


**Item category:** Rockets, with inert head

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 1.3C, UN0183, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Rockets, with inert head 1.3C UN0183 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Rockets, with inert head — Postal shipping restrictions by item category


**Item category:** Rosin oil

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 3, UN1286, packing group II, III; domestic mail air: Prohibited; domestic mail surface: 3A

> Rosin oil 3 UN1286 II, III Prohibited 3A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Rosin oil — Postal shipping restrictions by item category


**Item category:** Rubber scrap or shoddy, powdered or granulated, not exceeding 840 microns and rubber contend exceeding 45 percent

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.1, UN1345, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Rubber scrap or shoddy, powdered or granulated, not exceeding 840 microns and rubber contend exceeding 45 percent 4.1 UN1345 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Rubber scrap or shoddy, powdered or granulated, not exceeding 840 microns and rubber contend exceeding 45 percent — Postal shipping restrictions by item category


**Item category:** Rubber solution

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail: surface only (air prohibited)

**Conditions:** Hazard class 3, UN1287, packing group II, III; domestic mail air: Prohibited; domestic mail surface: 3A

> Rubber solution 3 UN1287 II, III Prohibited 3A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Rubber solution — Postal shipping restrictions by item category


**Item category:** Rubidium hydroxide solution

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN2677, packing group II, III; domestic mail air: 8A; domestic mail surface: 8A

> Rubidium hydroxide solution 8 UN2677 II, III 8A 8A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Rubidium hydroxide solution — Postal shipping restrictions by item category


**Item category:** Rubidium hydroxide

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN2678, packing group II; domestic mail air: 8A; domestic mail surface: 8A

> Rubidium hydroxide 8 UN2678 II 8A 8A

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Rubidium hydroxide — Postal shipping restrictions by item category


**Item category:** Rubidium

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.3, UN1423, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Rubidium 4.3 UN1423 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Rubidium — Postal shipping restrictions by item category


**Item category:** Safety Fuses (UN0105, Division 1.4S)

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic surface transportation only

**Conditions:** Mailable only with prior written approval from director, Product Classification; must be prepared per Packaging Instruction 1B; shipping paper required

> Safety Fuses (UN0105): Consists of a black powder core over-spun with yarns, waterproofing compounds, and/or tapes. Safety fuses identified as UN0105 and classified as Division 1.4S are mailable only when prior written approval has been granted by the director, Product Classification

Source: <https://pe.usps.com/text/pub52/pub52c3_020.htm>

Safety Fuses (UN0105, Division 1.4S) — Postal shipping restrictions by item category

carrier, conditions, item_category, scope


**Item category:** Safety matches (book, card, or strike-on-box)

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail via surface transportation only

**Conditions:** Permitted only in domestic mail via surface transportation; must follow Packaging Instruction 4B; mailpieces marked 'Surface Only' or 'Surface Mail Only'

> Safety matches: Book, card, or strike-on-box safety matches are permitted only in domestic mail via surface transportation.

Source: <https://pe.usps.com/text/pub52/pub52c3_023.htm>

Safety matches (book, card, or strike-on-box) — Postal shipping restrictions by item category


**Item category:** Safety Matches

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** international

**Conditions:** Safety matches must be sent via ground transportation and cannot be mailed internationally.

> Safety matches must be sent via ground transportation and cannot be mailed internationally.

Source: <https://www.usps.com/ship/shipping-restrictions.htm>

Safety Matches — Postal shipping restrictions by item category


**Item category:** secButyl chloroformate

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, NA2742, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> secButyl chloroformate 6.1 NA2742 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

secButyl chloroformate — Postal shipping restrictions by item category


**Item category:** Seed cake, containing vegetable oil solvent extractions and expelled seeds, with not more than 10 percent of oil and when the amount of moisture is higher than 11 percent, with not more than 20 percent of oil and moisture combined

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN1386, packing group III; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Seed cake, containing vegetable oil solvent extractions and expelled seeds, with not more than 10 percent of oil and when the amount of moisture is higher than 11 percent, with not more than 20 percent of oil and moisture combined 4.2 UN1386 III Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Seed cake, containing vegetable oil solvent extractions and expelled seeds, with not more than 10 percent of oil and when the amount of moisture is higher than 11 percent, with not more than 20 percent of oil and moisture combined — Postal shipping restrictions by item category


**Item category:** Seed cake with more than 1.5 percent oil and not more than 11 percent moisture

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN1386, packing group III; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Seed cake with more than 1.5 percent oil and not more than 11 percent moisture 4.2 UN1386 III Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Seed cake with more than 1.5 percent oil and not more than 11 percent moisture — Postal shipping restrictions by item category


**Item category:** Seed cake with not more than 1.5 percent oil and not more than 11 percent moisture

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN2217, packing group III; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Seed cake with not more than 1.5 percent oil and not more than 11 percent moisture 4.2 UN2217 III Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Seed cake with not more than 1.5 percent oil and not more than 11 percent moisture — Postal shipping restrictions by item category


**Item category:** Selenates or Selenites

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN2630, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Selenates or Selenites 6.1 UN2630 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Selenates or Selenites — Postal shipping restrictions by item category


**Item category:** Selenic acid

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN1905, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Selenic acid 8 UN1905 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Selenic acid — Postal shipping restrictions by item category


**Item category:** Selenium compound, liquid, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN3440, packing group I, II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Selenium compound, liquid, n.o.s. 6.1 UN3440 I, II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Selenium compound, liquid, n.o.s. — Postal shipping restrictions by item category


**Item category:** Selenium compound, solid, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN3283, packing group I, II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Selenium compound, solid, n.o.s. 6.1 UN3283 I, II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Selenium compound, solid, n.o.s. — Postal shipping restrictions by item category


**Item category:** Selenium disulfide

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 6.1, UN2657, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Selenium disulfide 6.1 UN2657 II Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Selenium disulfide — Postal shipping restrictions by item category


**Item category:** Selenium hexafluoride

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 2.3, UN2194, packing group not stated; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Selenium hexafluoride 2.3 UN2194 Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Selenium hexafluoride — Postal shipping restrictions by item category


**Item category:** Selenium nitride

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Listed as Forbidden in the Pub 52 Appendix A mailability guide; Prohibited in domestic mail by air and by surface.

> Selenium nitride Forbidden Prohibited Prohibited Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Selenium nitride — Postal shipping restrictions by item category


**Item category:** Selenium oxychloride

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 8, UN2879, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Selenium oxychloride 8 UN2879 I Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Selenium oxychloride — Postal shipping restrictions by item category


**Item category:** Self-heating liquid, corrosive, inorganic, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN3188, packing group II, III; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Self-heating liquid, corrosive, inorganic, n.o.s. 4.2 UN3188 II, III Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Self-heating liquid, corrosive, inorganic, n.o.s. — Postal shipping restrictions by item category


**Item category:** Self-heating liquid, corrosive, organic, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN3185, packing group II, III; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Self-heating liquid, corrosive, organic, n.o.s. 4.2 UN3185 II, III Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Self-heating liquid, corrosive, organic, n.o.s. — Postal shipping restrictions by item category


**Item category:** Self-heating liquid, inorganic, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN3186, packing group II, III; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Self-heating liquid, inorganic, n.o.s. 4.2 UN3186 II, III Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Self-heating liquid, inorganic, n.o.s. — Postal shipping restrictions by item category


**Item category:** Self-heating liquid, organic, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN3183, packing group II, III; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Self-heating liquid, organic, n.o.s. 4.2 UN3183 II, III Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Self-heating liquid, organic, n.o.s. — Postal shipping restrictions by item category


**Item category:** Self-heating liquid, toxic, inorganic, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN3187, packing group II, III; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Self-heating liquid, toxic, inorganic, n.o.s. 4.2 UN3187 II, III Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Self-heating liquid, toxic, inorganic, n.o.s. — Postal shipping restrictions by item category


**Item category:** Self-heating liquid, toxic, organic, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN3184, packing group II, III; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Self-heating liquid, toxic, organic, n.o.s. 4.2 UN3184 II, III Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Self-heating liquid, toxic, organic, n.o.s. — Postal shipping restrictions by item category


**Item category:** Self-heating solid, corrosive, inorganic, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN3192, packing group II, III; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Self-heating solid, corrosive, inorganic, n.o.s. 4.2 UN3192 II, III Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Self-heating solid, corrosive, inorganic, n.o.s. — Postal shipping restrictions by item category


**Item category:** Self-heating solid, corrosive, organic, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** domestic mail (air and surface)

**Conditions:** Hazard class 4.2, UN3126, packing group II, III; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Self-heating solid, corrosive, organic, n.o.s. 4.2 UN3126 II, III Prohibited Prohibited

Source: <https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf>

Self-heating solid, corrosive, organic, n.o.s. — Postal shipping restrictions by item category