**Item category:** Methyl isobutyl ketone

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN1245, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Methyl isobutyl ketone 3 UN1245 II Prohibited 3A

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

Methyl isobutyl ketone — Postal shipping restrictions by item category


**Item category:** Methyl isocyanate

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN2480, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Methyl isocyanate 6.1 UN2480 I Prohibited Prohibited

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

Methyl isocyanate — Postal shipping restrictions by item category


**Item category:** Methyl isopropenyl ketone, inhibited

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN1246, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Methyl isopropenyl ketone, inhibited 3 UN1246 II Prohibited 3A

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

Methyl isopropenyl ketone, inhibited — Postal shipping restrictions by item category


**Item category:** Methyl isothiocyanate

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN2477, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Methyl isothiocyanate 6.1 UN2477 I Prohibited Prohibited

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

Methyl isothiocyanate — Postal shipping restrictions by item category


**Item category:** Methyl isovalerate

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2400, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Methyl isovalerate 3 UN2400 II Prohibited 3A

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

Methyl isovalerate — Postal shipping restrictions by item category


**Item category:** Methyl magnesium bromide, in ethyl ether

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 4.3, UN1928, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Methyl magnesium bromide, in ethyl ether 4.3 UN1928 I Prohibited Prohibited

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

Methyl magnesium bromide, in ethyl ether — Postal shipping restrictions by item category


**Item category:** Methyl mercaptan

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 2.3, UN1064, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Methyl mercaptan 2.3 UN1064 n/a Prohibited Prohibited

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

Methyl mercaptan — Postal shipping restrictions by item category


**Item category:** Methyl methacrylate monomer, stabilized

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN1247, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Methyl methacrylate monomer, stabilized 3 UN1247 II Prohibited 3A

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

Methyl methacrylate monomer, stabilized — Postal shipping restrictions by item category


**Item category:** Methyl nitramine (dry)

**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.

> Methyl nitramine (dry) Forbidden Prohibited Prohibited Prohibited Prohibited

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

Methyl nitramine (dry) — Postal shipping restrictions by item category


**Item category:** Methyl nitrate

**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.

> Methyl nitrate Forbidden Prohibited Prohibited Prohibited Prohibited

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

Methyl nitrate — Postal shipping restrictions by item category


**Item category:** Methyl nitrite

**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.

> Methyl nitrite Forbidden Prohibited Prohibited Prohibited Prohibited

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

Methyl nitrite — Postal shipping restrictions by item category


**Item category:** Methyl orthosilicate

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN2606, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Methyl orthosilicate 6.1 UN2606 I Prohibited Prohibited

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

Methyl orthosilicate — Postal shipping restrictions by item category


**Item category:** Methyl phosphonic dichloride

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, NA9206, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Methyl phosphonic dichloride 6.1 NA9206 I Prohibited Prohibited

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

Methyl phosphonic dichloride — Postal shipping restrictions by item category


**Item category:** Methyl phosphonous dichloride, pyrophoric liquid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, NA2845, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Methyl phosphonous dichloride, pyrophoric liquid 6.1 NA2845 I Prohibited Prohibited

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

Methyl phosphonous dichloride, pyrophoric liquid — Postal shipping restrictions by item category


**Item category:** Methyl picric acid (heavy metal salts 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.

> Methyl picric acid (heavy metal salts of) Forbidden Prohibited Prohibited Prohibited Prohibited

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

Methyl picric acid (heavy metal salts of) — Postal shipping restrictions by item category


**Item category:** Methyl propionate

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN1248, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Methyl propionate 3 UN1248 II Prohibited 3A

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

Methyl propionate — Postal shipping restrictions by item category


**Item category:** Methyl propyl ether

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2612, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Methyl propyl ether 3 UN2612 II Prohibited 3A

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

Methyl propyl ether — Postal shipping restrictions by item category


**Item category:** Methyl propyl ketone

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN1249, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Methyl propyl ketone 3 UN1249 II Prohibited 3A

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

Methyl propyl ketone — Postal shipping restrictions by item category


**Item category:** Methyl tertbutyl ether

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2398, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Methyl tertbutyl ether 3 UN2398 II Prohibited 3A

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

Methyl tertbutyl ether — Postal shipping restrictions by item category


**Item category:** Methyl trichloroacetate

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 6.1, UN2533, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> Methyl trichloroacetate 6.1 UN2533 III 6A 6A

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

Methyl trichloroacetate — Postal shipping restrictions by item category


**Item category:** Methyl trimethylol methane trinitrate

**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.

> Methyl trimethylol methane trinitrate Forbidden Prohibited Prohibited Prohibited Prohibited

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

Methyl trimethylol methane trinitrate — Postal shipping restrictions by item category


**Item category:** Methyl vinyl ketone, stabilized

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN1251, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Methyl vinyl ketone, stabilized 6.1 UN1251 I Prohibited Prohibited

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

Methyl vinyl ketone, stabilized — Postal shipping restrictions by item category


**Item category:** Methylal

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 3, UN1234, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Methylal 3 UN1234 II Prohibited Prohibited

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

Methylal — Postal shipping restrictions by item category


**Item category:** Methylamine, anhydrous

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 2.1, UN1061, packing group n/a; domestic mail air: Prohibited; domestic mail surface: 2A

> Methylamine, anhydrous 2.1 UN1061 n/a Prohibited 2A

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

Methylamine, anhydrous — Postal shipping restrictions by item category


**Item category:** Methylamine, aqueous solution

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN1235, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Methylamine, aqueous solution 3 UN1235 II Prohibited 3A

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

Methylamine, aqueous solution — Postal shipping restrictions by item category


**Item category:** Methylamine dinitramine and dry salts thereof

**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.

> Methylamine dinitramine and dry salts thereof Forbidden Prohibited Prohibited Prohibited Prohibited

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

Methylamine dinitramine and dry salts thereof — Postal shipping restrictions by item category


**Item category:** Methylamine nitroform

**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.

> Methylamine nitroform Forbidden Prohibited Prohibited Prohibited Prohibited

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

Methylamine nitroform — Postal shipping restrictions by item category


**Item category:** Methylamine perchlorate (dry)

**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.

> Methylamine perchlorate (dry) Forbidden Prohibited Prohibited Prohibited Prohibited

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

Methylamine perchlorate (dry) — Postal shipping restrictions by item category


**Item category:** Methylamyl acetate

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN1233, packing group III; domestic mail air: Prohibited; domestic mail surface: 3A

> Methylamyl acetate 3 UN1233 III Prohibited 3A

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

Methylamyl acetate — Postal shipping restrictions by item category


**Item category:** Methylchlorosilane

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 2.3, UN2534, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Methylchlorosilane 2.3 UN2534 n/a Prohibited Prohibited

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

Methylchlorosilane — Postal shipping restrictions by item category


**Item category:** Methylcyclohexane

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2296, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Methylcyclohexane 3 UN2296 II Prohibited 3A

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

Methylcyclohexane — Postal shipping restrictions by item category


**Item category:** Methylcyclohexanols, flammable

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2617, packing group III; domestic mail air: Prohibited; domestic mail surface: 3A

> Methylcyclohexanols, flammable 3 UN2617 III Prohibited 3A

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

Methylcyclohexanols, flammable — Postal shipping restrictions by item category


**Item category:** Methylcyclohexanone

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2297, packing group III; domestic mail air: Prohibited; domestic mail surface: 3A

> Methylcyclohexanone 3 UN2297 III Prohibited 3A

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

Methylcyclohexanone — Postal shipping restrictions by item category


**Item category:** Methylcyclopentane

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2298, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Methylcyclopentane 3 UN2298 II Prohibited 3A

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

Methylcyclopentane — Postal shipping restrictions by item category


**Item category:** Methyldichloroarsine

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, NA1556, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Methyldichloroarsine 6.1 NA1556 I Prohibited Prohibited

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

Methyldichloroarsine — Postal shipping restrictions by item category


**Item category:** Methyldichlorosilane

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 4.3, UN1242, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Methyldichlorosilane 4.3 UN1242 I Prohibited Prohibited

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

Methyldichlorosilane — Postal shipping restrictions by item category


**Item category:** Methylene glycol dinitrate

**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.

> Methylene glycol dinitrate Forbidden Prohibited Prohibited Prohibited Prohibited

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

Methylene glycol dinitrate — Postal shipping restrictions by item category


**Item category:** Methylhydrazine

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN1244, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Methylhydrazine 6.1 UN1244 I Prohibited Prohibited

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

Methylhydrazine — Postal shipping restrictions by item category


**Item category:** Methylpentadienes

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2461, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Methylpentadienes 3 UN2461 II Prohibited 3A

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

Methylpentadienes — Postal shipping restrictions by item category


**Item category:** Methylphenyldichlorosilane

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 8, UN2437, packing group II; domestic mail air: 8A; domestic mail surface: 8A

> Methylphenyldichlorosilane 8 UN2437 II 8A 8A

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

Methylphenyldichlorosilane — Postal shipping restrictions by item category


**Item category:** Methyltetrahydrofuran

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2536, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Methyltetrahydrofuran 3 UN2536 II Prohibited 3A

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

Methyltetrahydrofuran — Postal shipping restrictions by item category


**Item category:** Methyltrichlorosilane

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 3, UN1250, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Methyltrichlorosilane 3 UN1250 I Prohibited Prohibited

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

Methyltrichlorosilane — Postal shipping restrictions by item category


**Item category:** Mines with bursting charge

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 1.1D, UN0137, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Mines with bursting charge 1.1D UN0137 II Prohibited Prohibited

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

Mines with bursting charge — Postal shipping restrictions by item category


**Item category:** Miscellaneous hazardous materials (Hazard Class 9) — international mail

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** international mail

**Conditions:** All miscellaneous hazardous materials are prohibited internationally except certain magnetized materials and small consumer-type lithium batteries installed in their equipment

> International Mail: All miscellaneous hazardous materials are prohibited, except for certain magnetized materials as permitted in 349.242 (a) and IMM 136.1g, and small consumer-type lithium batteries (installed in the equipment they operate)

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

Miscellaneous hazardous materials (Hazard Class 9) — international mail — Postal shipping restrictions by item category


**Item category:** Model fuel for glow-plug engines

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Mailable only if qualifies as Limited Quantity surface material and meets quantity limitations and packaging requirements; Packaging Instruction 3A must be followed

> Model Fuel (for Glow-Plug Engines): A flammable liquid with a flashpoint ranging from 65° F to 75° F. It is mailable only if it qualifies as a Limited Quantity surface material

Source: <https://pe.usps.com/text/pub52/pub52c3_022.htm>

Model fuel for glow-plug engines — Postal shipping restrictions by item category


**Item category:** Model rocket motor

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 1.4C, NA0276, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Model rocket motor 1.4C NA0276 II Prohibited Prohibited

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

Model rocket motor — Postal shipping restrictions by item category


**Item category:** Molybdenum pentachloride

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 8, UN2508, packing group III; domestic mail air: 8A; domestic mail surface: 8A

> Molybdenum pentachloride 8 UN2508 III 8A 8A

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

Molybdenum pentachloride — Postal shipping restrictions by item category


**Item category:** Monochloroacetone (unstabilized)

**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.

> Monochloroacetone (unstabilized) Forbidden Prohibited Prohibited Prohibited Prohibited

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

Monochloroacetone (unstabilized) — Postal shipping restrictions by item category


**Item category:** Morpholine

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2054, packing group III; domestic mail air: Prohibited; domestic mail surface: 3A

> Morpholine 3 UN2054 III Prohibited 3A

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

Morpholine — Postal shipping restrictions by item category


**Item category:** Motor fuel anti-knock mixture, flammable

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN3483, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Motor fuel anti-knock mixture, flammable 6.1 UN3483 I Prohibited Prohibited

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

Motor fuel anti-knock mixture, flammable — Postal shipping restrictions by item category


**Item category:** Motor fuel anti-knock mixtures

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN1649, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Motor fuel anti-knock mixtures 6.1 UN1649 I Prohibited Prohibited

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

Motor fuel anti-knock mixtures — Postal shipping restrictions by item category


**Item category:** N-Aminoethylpiperazine

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 8, UN2815, packing group III; domestic mail air: 8A; domestic mail surface: 8A

> N-Aminoethylpiperazine 8 UN2815 III 8A 8A

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

N-Aminoethylpiperazine — Postal shipping restrictions by item category


**Item category:** n-Amyl methyl ketone

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN1110, packing group III; domestic mail air: Prohibited; domestic mail surface: 3A

> n-Amyl methyl ketone 3 UN1110 III Prohibited 3A

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

n-Amyl methyl ketone — Postal shipping restrictions by item category


**Item category:** n-Butyl isocyanate

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN2485, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> n-Butyl isocyanate 6.1 UN2485 I Prohibited Prohibited

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

n-Butyl isocyanate — Postal shipping restrictions by item category


**Item category:** n-Butyl methacrylate, stabilized

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2227, packing group III; domestic mail air: Prohibited; domestic mail surface: 3A

> n-Butyl methacrylate, stabilized 3 UN2227 III Prohibited 3A

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

n-Butyl methacrylate, stabilized — Postal shipping restrictions by item category


**Item category:** n-Butyl peroxydicarbonate, with more than 52 percent in solution

**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.

> n-Butyl peroxydicarbonate, with more than 52 percent in solution Forbidden Prohibited Prohibited Prohibited Prohibited

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

n-Butyl peroxydicarbonate, with more than 52 percent in solution — Postal shipping restrictions by item category


**Item category:** n-Butylamine

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 3, UN1125, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> n-Butylamine 3 UN1125 II Prohibited Prohibited

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

n-Butylamine — Postal shipping restrictions by item category


**Item category:** N-Butylaniline

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN2378, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> N-Butylaniline 6.1 UN2378 II Prohibited Prohibited

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

N-Butylaniline — Postal shipping restrictions by item category


**Item category:** n-Decane

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2247, packing group III; domestic mail air: Prohibited; domestic mail surface: 3A

> n-Decane 3 UN2247 III Prohibited 3A

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

n-Decane — Postal shipping restrictions by item category


**Item category:** N-Ethyl-N-benzylaniline

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 6.1, UN2274, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> N-Ethyl-N-benzylaniline 6.1 UN2274 III 6A 6A

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

N-Ethyl-N-benzylaniline — Postal shipping restrictions by item category


**Item category:** N-Ethylaniline

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 6.1, UN2272, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> N-Ethylaniline 6.1 UN2272 III 6A 6A

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

N-Ethylaniline — Postal shipping restrictions by item category


**Item category:** N-Ethylbenzyltoluidines liquid

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 6.1, UN2753, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> N-Ethylbenzyltoluidines liquid 6.1 UN2753 III 6A 6A

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

N-Ethylbenzyltoluidines liquid — Postal shipping restrictions by item category


**Item category:** N-Ethylbenzyltoluidines, solid

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 6.1, UN3460, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> N-Ethylbenzyltoluidines, solid 6.1 UN3460 III 6A 6A

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

N-Ethylbenzyltoluidines, solid — Postal shipping restrictions by item category


**Item category:** N-Ethyltoluidines

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN2754, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> N-Ethyltoluidines 6.1 UN2754 II Prohibited Prohibited

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

N-Ethyltoluidines — Postal shipping restrictions by item category


**Item category:** n-Heptaldehyde

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN3056, packing group III; domestic mail air: Prohibited; domestic mail surface: 3A

> n-Heptaldehyde 3 UN3056 III Prohibited 3A

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

n-Heptaldehyde — Postal shipping restrictions by item category


**Item category:** n-Heptane

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2278, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> n-Heptane 3 UN2278 II Prohibited 3A

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

n-Heptane — Postal shipping restrictions by item category


**Item category:** N-Methylaniline

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 6.1, UN2294, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> N-Methylaniline 6.1 UN2294 III 6A 6A

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

N-Methylaniline — Postal shipping restrictions by item category


**Item category:** N-Methylbutylamine

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 3, UN2945, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> N-Methylbutylamine 3 UN2945 II Prohibited Prohibited

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

N-Methylbutylamine — Postal shipping restrictions by item category


**Item category:** N-n-Butyl imidazole

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN2690, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> N-n-Butyl imidazole 6.1 UN2690 II Prohibited Prohibited

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

N-n-Butyl imidazole — Postal shipping restrictions by item category


**Item category:** N,N’-Dichlorazodicarbonamidine (salts of) (dry)

**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.

> N,N’-Dichlorazodicarbonamidine (salts of) (dry) Forbidden Prohibited Prohibited Prohibited Prohibited

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

N,N’-Dichlorazodicarbonamidine (salts of) (dry) — Postal shipping restrictions by item category


**Item category:** N,N-Diethylaniline

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 6.1, UN2432, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> N,N-Diethylaniline 6.1 UN2432 III 6A 6A

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

N,N-Diethylaniline — Postal shipping restrictions by item category


**Item category:** N,N-Diethylethylenediamine

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 8, UN2685, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> N,N-Diethylethylenediamine 8 UN2685 II Prohibited Prohibited

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

N,N-Diethylethylenediamine — Postal shipping restrictions by item category


**Item category:** N,N-Dimethylaniline

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN2253, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> N,N-Dimethylaniline 6.1 UN2253 II Prohibited Prohibited

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

N,N-Dimethylaniline — Postal shipping restrictions by item category


**Item category:** N,N-Dimethylcyclohexlamine

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 8, UN2264, packing group II; domestic mail air: 8A; domestic mail surface: 8A

> N,N-Dimethylcyclohexlamine 8 UN2264 II 8A 8A

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

N,N-Dimethylcyclohexlamine — Postal shipping restrictions by item category


**Item category:** N,N-Dimethylformamide

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2265, packing group III; domestic mail air: Prohibited; domestic mail surface: 3A

> N,N-Dimethylformamide 3 UN2265 III Prohibited 3A

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

N,N-Dimethylformamide — Postal shipping restrictions by item category


**Item category:** N,N’-(hexanitrodiphenyl) ethylene dinitramine (dry)

**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.

> N,N’-(hexanitrodiphenyl) ethylene dinitramine (dry) Forbidden Prohibited Prohibited Prohibited Prohibited

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

N,N’-(hexanitrodiphenyl) ethylene dinitramine (dry) — Postal shipping restrictions by item category


**Item category:** N-Nitro-N-methylglycolamide nitrate

**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.

> N-Nitro-N-methylglycolamide nitrate Forbidden Prohibited Prohibited Prohibited Prohibited

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

N-Nitro-N-methylglycolamide nitrate — Postal shipping restrictions by item category


**Item category:** N-Nitroaniline

**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.

> N-Nitroaniline Forbidden Prohibited Prohibited Prohibited Prohibited

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

N-Nitroaniline — Postal shipping restrictions by item category


**Item category:** n-Propanol or Propyl alcohol, normal

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN1274, packing group II, III; domestic mail air: Prohibited; domestic mail surface: 3A

> n-Propanol or Propyl alcohol, normal 3 UN1274 II, III Prohibited 3A

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

n-Propanol or Propyl alcohol, normal — Postal shipping restrictions by item category


**Item category:** n-Propyl acetate

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN1276, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> n-Propyl acetate 3 UN1276 II Prohibited 3A

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

n-Propyl acetate — Postal shipping restrictions by item category


**Item category:** Nail polish

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic US

**Conditions:** Classified as flammable liquid. Requires hazmat declaration and compliant packaging. $50 noncompliance fee if undeclared, effective July 12, 2026.

> Nail polish | Flammable liquid | UN1263

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

Nail polish — Postal shipping restrictions by item category


**Item category:** Nail polish

**Carrier:** USPS

**Restriction type:** hazmat declaration required

**Scope:** online marketplace seller shipments (Poshmark)

**Conditions:** Subject to USPS hazmat requirements and Poshmark Terms of Service; $50 USPS noncompliance fee applies if improperly declared/labeled; Poshmark absorbs $45 of fee after August 1 2026, seller pays $5

> regulated contents (perfume, nail polish, aerosol sprays, electronics with lithium-ion batteries)

Source: <https://blog.poshmark.com/2026/07/09/59935/>

carrier, conditions, restriction_type, scope


**Item category:** Nail polish

**Carrier:** USPS

**Restriction type:** hazmat declaration required

**Scope:** seller shipments (Etsy)

**Conditions:** May have special shipping requirements under USPS hazardous materials rules; $50 noncompliance fee for undeclared or improperly prepared hazardous materials effective July 12 2026

> Some items, such as certain candles, perfumes, aerosols, nail polish, or items containing lithium batteries, may have special shipping requirements.

Source: <https://www.valueaddedresource.net/poshmark-cover-usps-hazardous-non-compliance-fee/>


**Item category:** Nail polish and nail polish remover

**Carrier:** USPS

**Restriction type:** hazmat declaration required

**Scope:** commercial package shipments

**Conditions:** Listed by the Department of Transportation as posing a significant safety risk while being transported; $7.50 hazmat handling fee for Priority Mail; $50 noncompliance fee for packages not properly declared and labeled across all commercial packages including Ground Advantage (effective July 12 2026)

> Essential oils, nail polish (and nail polish remover), perfumes and colognes, hand sanitizer, inks, stains and varnishes, hairspray, and electronics with a lithium battery are among the products listed by the Department of Transportation as posing a significant safety risk while being transported.

Source: <https://www.ecommercebytes.com/2026/07/05/new-usps-noncompliance-fee-could-take-sellers-by-surprise/>

Nail polish and nail polish remover — Postal shipping restrictions by item category


**Item category:** Nail polish remover

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic US

**Conditions:** Classified as flammable liquid (acetone). Requires hazmat declaration and compliant packaging. $50 noncompliance fee if undeclared, effective July 12, 2026.

> Nail polish remover | Flammable liquid (acetone) | UN1090

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

Nail polish remover — Postal shipping restrictions by item category


**Item category:** Nail Polish

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic

**Conditions:** Flammable nail polishes may be mailed domestically if they are a consumer commodity; some may only be sent by ground

> If the nail polish you want to mail is flammable, you are responsible for knowing its flashpoint and toxicity. Flammable nail polishes may be mailed domestically if they are a consumer commodity. Some nail polishes may only be sent by ground transportation.

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

Nail Polish — Postal shipping restrictions by item category


**Item category:** Naphthalene, crude or Naphthalene, refined

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 4.1, UN1334, packing group III; domestic mail air: Prohibited; domestic mail surface: 4A

> Naphthalene, crude or Naphthalene, refined 4.1 UN1334 III Prohibited 4A

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

Naphthalene, crude or Naphthalene, refined — Postal shipping restrictions by item category


**Item category:** Naphthalene diozonide

**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.

> Naphthalene diozonide Forbidden Prohibited Prohibited Prohibited Prohibited

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

Naphthalene diozonide — Postal shipping restrictions by item category


**Item category:** Naphthalene, molten

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 4.1, UN2304, packing group III; domestic mail air: Prohibited; domestic mail surface: 4A

> Naphthalene, molten 4.1 UN2304 III Prohibited 4A

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

Naphthalene, molten — Postal shipping restrictions by item category


**Item category:** Naphthylamineperchlorate

**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.

> Naphthylamineperchlorate Forbidden Prohibited Prohibited Prohibited Prohibited

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

Naphthylamineperchlorate — Postal shipping restrictions by item category


**Item category:** Naphthylthiourea

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN1651, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Naphthylthiourea 6.1 UN1651 II Prohibited Prohibited

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

Naphthylthiourea — Postal shipping restrictions by item category


**Item category:** Naphthylurea

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN1652, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Naphthylurea 6.1 UN1652 II Prohibited Prohibited

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

Naphthylurea — Postal shipping restrictions by item category


**Item category:** Neon, compressed

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 2.2, UN1065, packing group n/a; domestic mail air: 2B; domestic mail surface: 2B

> Neon, compressed 2.2 UN1065 n/a 2B 2B

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

Neon, compressed — Postal shipping restrictions by item category


**Item category:** Neon, refrigerated liquid (cryogenic liquid)

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 2.2, UN1913, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Neon, refrigerated liquid (cryogenic liquid) 2.2 UN1913 n/a Prohibited Prohibited

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

Neon, refrigerated liquid (cryogenic liquid) — Postal shipping restrictions by item category


**Item category:** Nickel cyanide

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN1653, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nickel cyanide 6.1 UN1653 II Prohibited Prohibited

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

Nickel cyanide — Postal shipping restrictions by item category


**Item category:** Nickel nitrate

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 5.1, UN2725, packing group III; domestic mail air: 5A; domestic mail surface: 5A

> Nickel nitrate 5.1 UN2725 III 5A 5A

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

Nickel nitrate — Postal shipping restrictions by item category


**Item category:** Nickel nitrite

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 5.1, UN2726, packing group III; domestic mail air: 5A; domestic mail surface: 5A

> Nickel nitrite 5.1 UN2726 III 5A 5A

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

Nickel nitrite — Postal shipping restrictions by item category


**Item category:** Nickel picrate

**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.

> Nickel picrate Forbidden Prohibited Prohibited Prohibited Prohibited

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

Nickel picrate — Postal shipping restrictions by item category


**Item category:** Nicotine compounds, liquid, n.o.s. or Nicotine preparations, liquid, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN3144, packing group I, II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nicotine compounds, liquid, n.o.s. or Nicotine preparations, liquid, n.o.s. 6.1 UN3144 I, II Prohibited Prohibited

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

Nicotine compounds, liquid, n.o.s. or Nicotine preparations, liquid, n.o.s. — Postal shipping restrictions by item category


**Item category:** Nicotine compounds, solid, n.o.s. or Nicotine preparations, solid, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN1655, packing group I, II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nicotine compounds, solid, n.o.s. or Nicotine preparations, solid, n.o.s. 6.1 UN1655 I, II Prohibited Prohibited

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

Nicotine compounds, solid, n.o.s. or Nicotine preparations, solid, n.o.s. — Postal shipping restrictions by item category


**Item category:** Nicotine hydrochloride liquid or solution

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN1656, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nicotine hydrochloride liquid or solution 6.1 UN1656 II Prohibited Prohibited

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

Nicotine hydrochloride liquid or solution — Postal shipping restrictions by item category


**Item category:** Nicotine hydrochloride, solid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN3444, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nicotine hydrochloride, solid 6.1 UN3444 II Prohibited Prohibited

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

Nicotine hydrochloride, solid — Postal shipping restrictions by item category


**Item category:** Nicotine salicylate

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN1657, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nicotine salicylate 6.1 UN1657 II Prohibited Prohibited

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

Nicotine salicylate — Postal shipping restrictions by item category


**Item category:** Nicotine sulfate, solid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN3445, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nicotine sulfate, solid 6.1 UN3445 II Prohibited Prohibited

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

Nicotine sulfate, solid — Postal shipping restrictions by item category


**Item category:** Nicotine sulfate, solution

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN1658, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nicotine sulfate, solution 6.1 UN1658 II Prohibited Prohibited

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

Nicotine sulfate, solution — Postal shipping restrictions by item category


**Item category:** Nicotine tartrate

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN1659, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nicotine tartrate 6.1 UN1659 II Prohibited Prohibited

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

Nicotine tartrate — Postal shipping restrictions by item category


**Item category:** Nicotine

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN1654, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nicotine 6.1 UN1654 II Prohibited Prohibited

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

Nicotine — Postal shipping restrictions by item category


**Item category:** Nitophenols (o-; m-; p-;)

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 6.1, UN1663, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> Nitophenols (o-; m-; p-;) 6.1 UN1663 III 6A 6A

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

Nitophenols (o-; m-; p-;) — Postal shipping restrictions by item category


**Item category:** Nitrated paper (unstable)

**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.

> Nitrated paper (unstable) Forbidden Prohibited Prohibited Prohibited Prohibited

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

Nitrated paper (unstable) — Postal shipping restrictions by item category


**Item category:** Nitrates, inorganic, aqueous solution, n.o.s.

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 5.1, UN3218, packing group II, III; domestic mail air: 5A; domestic mail surface: 5A

> Nitrates, inorganic, aqueous solution, n.o.s. 5.1 UN3218 II, III 5A 5A

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

Nitrates, inorganic, aqueous solution, n.o.s. — Postal shipping restrictions by item category


**Item category:** Nitrates, inorganic, n.o.s.

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 5.1, UN1477, packing group II, III; domestic mail air: 5A; domestic mail surface: 5A

> Nitrates, inorganic, n.o.s. 5.1 UN1477 II, III 5A 5A

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

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


**Item category:** Nitrates of diazonium compounds

**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.

> Nitrates of diazonium compounds Forbidden Prohibited Prohibited Prohibited Prohibited

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

Nitrates of diazonium compounds — Postal shipping restrictions by item category


**Item category:** Nitrating acid mixtures, spent with more than 50 percent nitric acid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 8, UN1826, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrating acid mixtures, spent with more than 50 percent nitric acid 8 UN1826 I Prohibited Prohibited

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

Nitrating acid mixtures, spent with more than 50 percent nitric acid — Postal shipping restrictions by item category


**Item category:** Nitrating acid mixtures, spent with not more than 50 percent nitric acid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 8, UN1826, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrating acid mixtures, spent with not more than 50 percent nitric acid 8 UN1826 II Prohibited Prohibited

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

Nitrating acid mixtures, spent with not more than 50 percent nitric acid — Postal shipping restrictions by item category


**Item category:** Nitrating acid mixtures, with more than 50 percent nitric acid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 8, UN1796, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrating acid mixtures, with more than 50 percent nitric acid 8 UN1796 I Prohibited Prohibited

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

Nitrating acid mixtures, with more than 50 percent nitric acid — Postal shipping restrictions by item category


**Item category:** Nitrating acid mixtures, with not more than 50 percent nitric acid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 8, UN1796, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrating acid mixtures, with not more than 50 percent nitric acid 8 UN1796 II Prohibited Prohibited

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

Nitrating acid mixtures, with not more than 50 percent nitric acid — Postal shipping restrictions by item category


**Item category:** Nitric acid other than red fuming, with more than 70 percent nitric acid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 8, UN2031, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitric acid other than red fuming, with more than 70 percent nitric acid 8 UN2031 I Prohibited Prohibited

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

Nitric acid other than red fuming, with more than 70 percent nitric acid — Postal shipping restrictions by item category


**Item category:** Nitric acid other than red fuming, with not more than 70 percent nitric acid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 8, UN2031, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitric acid other than red fuming, with not more than 70 percent nitric acid 8 UN2031 II Prohibited Prohibited

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

Nitric acid other than red fuming, with not more than 70 percent nitric acid — Postal shipping restrictions by item category


**Item category:** Nitric acid, red fuming

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 8, UN2032, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitric acid, red fuming 8 UN2032 I Prohibited Prohibited

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

Nitric acid, red fuming — Postal shipping restrictions by item category


**Item category:** Nitric acid (UN2031, UN2032)

**Carrier:** USPS

**Restriction type:** prohibited

**Scope:** all mail

**Conditions:** Nonmailable corrosive

> Nitric Acid (UN2031, UN2032).

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

Nitric acid (UN2031, UN2032) — Postal shipping restrictions by item category


**Item category:** Nitric oxide and dinitrogen tetroxide mixtures or Nitric oxide and nitrogen dioxide mixtures

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 2.3, UN1975, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitric oxide and dinitrogen tetroxide mixtures or Nitric oxide and nitrogen dioxide mixtures 2.3 UN1975 n/a Prohibited Prohibited

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

Nitric oxide and dinitrogen tetroxide mixtures or Nitric oxide and nitrogen dioxide mixtures — Postal shipping restrictions by item category


**Item category:** Nitric oxide, compressed

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 2.3, UN1660, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitric oxide, compressed 2.3 UN1660 n/a Prohibited Prohibited

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

Nitric oxide, compressed — Postal shipping restrictions by item category


**Item category:** Nitriles, flammable, toxic, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 3, UN3273, packing group I, II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitriles, flammable, toxic, n.o.s. 3 UN3273 I, II Prohibited Prohibited

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

Nitriles, flammable, toxic, n.o.s. — Postal shipping restrictions by item category


**Item category:** Nitriles, toxic, flammable, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN3275, packing group I, II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitriles, toxic, flammable, n.o.s. 6.1 UN3275 I, II Prohibited Prohibited

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

Nitriles, toxic, flammable, n.o.s. — Postal shipping restrictions by item category


**Item category:** Nitriles, toxic, liquid, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN3276, packing group I, II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitriles, toxic, liquid, n.o.s. 6.1 UN3276 I, II Prohibited Prohibited

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

Nitriles, toxic, liquid, n.o.s. — Postal shipping restrictions by item category


**Item category:** Nitriles, toxic, solid, n.o.s.

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN3439, packing group I, II,; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitriles, toxic, solid, n.o.s. 6.1 UN3439 I, II, Prohibited Prohibited

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

Nitriles, toxic, solid, n.o.s. — Postal shipping restrictions by item category


**Item category:** Nitrites, inorganic, aqueous solution, n.o.s.

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 5.1, UN3219, packing group II, III; domestic mail air: 5A; domestic mail surface: 5A

> Nitrites, inorganic, aqueous solution, n.o.s. 5.1 UN3219 II, III 5A 5A

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

Nitrites, inorganic, aqueous solution, n.o.s. — Postal shipping restrictions by item category


**Item category:** Nitrites, inorganic, n.o.s.

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 5.1, UN2627, packing group II; domestic mail air: 5A; domestic mail surface: 5A

> Nitrites, inorganic, n.o.s. 5.1 UN2627 II 5A 5A

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

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


**Item category:** Nitro isobutane triol trinitrate

**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.

> 5.1 UN2627 II 5A 5A 3-Nitro-4-chlorobenzotrifluoride 6.1 UN2307 II Prohibited Prohibited Nitro isobutane triol trinitrate

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

Nitro isobutane triol trinitrate — Postal shipping restrictions by item category


**Item category:** Nitro urea

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 1.1D, UN0147, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitro urea 1.1D UN0147 II Prohibited Prohibited

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

Nitro urea — Postal shipping restrictions by item category


**Item category:** Nitroanilines (o-; m-; p-;) 6.1 Prohibited Prohibited Prohibited Prohibited Nitroanisole, liquid

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 6.1, UN2730, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> Nitroanilines (o-; m-; p-;) 6.1 Prohibited Prohibited Prohibited Prohibited Nitroanisole, liquid 6.1 UN2730 III 6A 6A

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

Nitroanilines (o-; m-; p-;) 6.1 Prohibited Prohibited Prohibited Prohibited Nitroanisole, liquid — Postal shipping restrictions by item category


**Item category:** Nitroanisole, solid

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 6.1, UN3458, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> Nitroanisole, solid 6.1 UN3458 III 6A 6A

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

Nitroanisole, solid — Postal shipping restrictions by item category


**Item category:** Nitrobenzene

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN1662, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrobenzene 6.1 UN1662 II Prohibited Prohibited

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

Nitrobenzene — Postal shipping restrictions by item category


**Item category:** Nitrobenzenesulfonic acid

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 8, UN2305, packing group II; domestic mail air: 8A; domestic mail surface: 8A

> Nitrobenzenesulfonic acid 8 UN2305 II 8A 8A

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

Nitrobenzenesulfonic acid — Postal shipping restrictions by item category


**Item category:** Nitrobenzotrifluorides, liquid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN2306, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrobenzotrifluorides, liquid 6.1 UN2306 II Prohibited Prohibited

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

Nitrobenzotrifluorides, liquid — Postal shipping restrictions by item category


**Item category:** Nitrobenzotrifluorides, solid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN3431, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrobenzotrifluorides, solid 6.1 UN3431 II Prohibited Prohibited

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

Nitrobenzotrifluorides, solid — Postal shipping restrictions by item category


**Item category:** Nitrobromobenzenes liquid

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 6.1, UN2732, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> Nitrobromobenzenes liquid 6.1 UN2732 III 6A 6A

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

Nitrobromobenzenes liquid — Postal shipping restrictions by item category


**Item category:** Nitrobromobenzenes solid

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 6.1, UN3459, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> Nitrobromobenzenes solid 6.1 UN3459 III 6A 6A

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

Nitrobromobenzenes solid — Postal shipping restrictions by item category


**Item category:** Nitrocellulose, dry or wetted with less than 25 percent water (or alcohol), by mass

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 1.1D, UN0340, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrocellulose, dry or wetted with less than 25 percent water (or alcohol), by mass 1.1D UN0340 II Prohibited Prohibited

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

Nitrocellulose, dry or wetted with less than 25 percent water (or alcohol), by mass — Postal shipping restrictions by item category


**Item category:** Nitrocellulose membrane filters, with not more than 12.6 percent nitrogen, by dry mass

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 4.1, UN3270, packing group II; domestic mail air: Prohibited; domestic mail surface: 4A

> Nitrocellulose membrane filters, with not more than 12.6 percent nitrogen, by dry mass 4.1 UN3270 II Prohibited 4A

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

Nitrocellulose membrane filters, with not more than 12.6 percent nitrogen, by dry mass — Postal shipping restrictions by item category


**Item category:** Nitrocellulose, plasticized with not less than 18 percent plasticizing substance, by mass

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 1.3C, UN0343, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrocellulose, plasticized with not less than 18 percent plasticizing substance, by mass 1.3C UN0343 II Prohibited Prohibited

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

Nitrocellulose, plasticized with not less than 18 percent plasticizing substance, by mass — Postal shipping restrictions by item category


**Item category:** Nitrocellulose, solution, flammable with not more than 12.6 percent nitrogen, by mass, and not more than 55 percent nitrocellulose

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2059, packing group II, III; domestic mail air: Prohibited; domestic mail surface: 3A

> Nitrocellulose, solution, flammable with not more than 12.6 percent nitrogen, by mass, and not more than 55 percent nitrocellulose 3 UN2059 II, III Prohibited 3A

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

Nitrocellulose, solution, flammable with not more than 12.6 percent nitrogen, by mass, and not more than 55 percent nitrocellulose — Postal shipping restrictions by item category


**Item category:** Nitrocellulose, unmodified or plasticized with less than 18 percent plasticizing substance, by mass

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 1.1D, UN0341, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrocellulose, unmodified or plasticized with less than 18 percent plasticizing substance, by mass 1.1D UN0341 II Prohibited Prohibited

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

Nitrocellulose, unmodified or plasticized with less than 18 percent plasticizing substance, by mass — Postal shipping restrictions by item category


**Item category:** Nitrocellulose, wetted with not less than 25 percent alcohol, by mass

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 1.3C, UN0342, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrocellulose, wetted with not less than 25 percent alcohol, by mass 1.3C UN0342 II Prohibited Prohibited

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

Nitrocellulose, wetted with not less than 25 percent alcohol, by mass — Postal shipping restrictions by item category


**Item category:** Nitrocellulose, with alcohol with not less than 25 percent alcohol, by mass, and with not more than 12.6 percent nitrogen, by dry mass

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 4.1, UN2556, packing group II; domestic mail air: Prohibited; domestic mail surface: 4A

> Nitrocellulose, with alcohol with not less than 25 percent alcohol, by mass, and with not more than 12.6 percent nitrogen, by dry mass 4.1 UN2556 II Prohibited 4A

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

Nitrocellulose, with alcohol with not less than 25 percent alcohol, by mass, and with not more than 12.6 percent nitrogen, by dry mass — Postal shipping restrictions by item category


**Item category:** Nitrocellulose, with not more than 12.6 percent, by dry mass mixture with or without plasticizer, with or without pigment

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 4.1, UN2557, packing group II; domestic mail air: Prohibited; domestic mail surface: 4A

> Nitrocellulose, with not more than 12.6 percent, by dry mass mixture with or without plasticizer, with or without pigment 4.1 UN2557 II Prohibited 4A

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

Nitrocellulose, with not more than 12.6 percent, by dry mass mixture with or without plasticizer, with or without pigment — Postal shipping restrictions by item category


**Item category:** Nitrocellulose with water with not less than 25 percent water, by mass

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 4.1, UN2555, packing group II; domestic mail air: Prohibited; domestic mail surface: 4A

> Nitrocellulose with water with not less than 25 percent water, by mass 4.1 UN2555 II Prohibited 4A

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

Nitrocellulose with water with not less than 25 percent water, by mass — Postal shipping restrictions by item category


**Item category:** Nitrocresols, liquid

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 6.1, UN3434, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> Nitrocresols, liquid 6.1 UN3434 III 6A 6A

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

Nitrocresols, liquid — Postal shipping restrictions by item category


**Item category:** Nitroethane

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2842, packing group III; domestic mail air: Prohibited; domestic mail surface: 3A

> Nitroethane 3 UN2842 III Prohibited 3A

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

Nitroethane — Postal shipping restrictions by item category


**Item category:** Nitroethyl nitrate

**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.

> Nitroethyl nitrate Forbidden Prohibited Prohibited Prohibited Prohibited

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

Nitroethyl nitrate — Postal shipping restrictions by item category


**Item category:** Nitroethylene polymer

**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.

> Nitroethylene polymer Forbidden Prohibited Prohibited Prohibited Prohibited

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

Nitroethylene polymer — Postal shipping restrictions by item category


**Item category:** Nitrogen, compressed

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 2.2, UN1066, packing group n/a; domestic mail air: 2B; domestic mail surface: 2B

> Nitrogen, compressed 2.2 UN1066 n/a 2B 2B

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

Nitrogen, compressed — Postal shipping restrictions by item category


**Item category:** Nitrogen, refrigerated liquid cryogenic liquid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 2.2, UN1977, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrogen, refrigerated liquid cryogenic liquid 2.2 UN1977 n/a Prohibited Prohibited

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

Nitrogen, refrigerated liquid cryogenic liquid — Postal shipping restrictions by item category


**Item category:** Nitrogen trichloride

**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.

> Nitrogen trichloride Forbidden Prohibited Prohibited Prohibited Prohibited

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

Nitrogen trichloride — Postal shipping restrictions by item category


**Item category:** Nitrogen trifluoride,

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 2.2, UN2451, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrogen trifluoride, 2.2 UN2451 n/a Prohibited Prohibited

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

Nitrogen trifluoride, — Postal shipping restrictions by item category


**Item category:** Nitrogen triiodide monoamine

**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.

> Nitrogen triiodide monoamine Forbidden Prohibited Prohibited Prohibited Prohibited

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

Nitrogen triiodide monoamine — Postal shipping restrictions by item category


**Item category:** Nitrogen triiodide

**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.

> Nitrogen triiodide Forbidden Prohibited Prohibited Prohibited Prohibited

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

Nitrogen triiodide — Postal shipping restrictions by item category


**Item category:** Nitrogen trioxide

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 2.3, UN2421, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrogen trioxide 2.3 UN2421 n/a Prohibited Prohibited

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

Nitrogen trioxide — Postal shipping restrictions by item category


**Item category:** Nitroglycerin, desensitized with not less than 40 percent non-volatile water insoluble phlegmatizer, by mass

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 1.1D, UN0143, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitroglycerin, desensitized with not less than 40 percent non-volatile water insoluble phlegmatizer, by mass 1.1D UN0143 II Prohibited Prohibited

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

Nitroglycerin, desensitized with not less than 40 percent non-volatile water insoluble phlegmatizer, by mass — Postal shipping restrictions by item category


**Item category:** Nitroglycerin, liquid, not desensitized

**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.

> Nitroglycerin, liquid, not desensitized Forbidden Prohibited Prohibited Prohibited Prohibited

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

Nitroglycerin, liquid, not desensitized — Postal shipping restrictions by item category


**Item category:** Nitroglycerin mixture, desensitized, liquid, flammable, n.o.s. with not more than 30 percent nitroglycerin, by mass

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 3, UN3343, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitroglycerin mixture, desensitized, liquid, flammable, n.o.s. with not more than 30 percent nitroglycerin, by mass 3 UN3343 n/a Prohibited Prohibited

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

Nitroglycerin mixture, desensitized, liquid, flammable, n.o.s. with not more than 30 percent nitroglycerin, by mass — Postal shipping restrictions by item category


**Item category:** Nitroglycerin mixture, desensitized, liquid, n.o.s. with not more than 30 percent nitroglycerin, by mass

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 3, UN3357, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitroglycerin mixture, desensitized, liquid, n.o.s. with not more than 30 percent nitroglycerin, by mass 3 UN3357 II Prohibited Prohibited

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

Nitroglycerin mixture, desensitized, liquid, n.o.s. with not more than 30 percent nitroglycerin, by mass — Postal shipping restrictions by item category


**Item category:** Nitroglycerin mixture, desensitized, solid, n.o.s. with more than 2 percent but not more than 10 percent nitroglycerin, by mass

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 4.1, UN3319, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitroglycerin mixture, desensitized, solid, n.o.s. with more than 2 percent but not more than 10 percent nitroglycerin, by mass 4.1 UN3319 II Prohibited Prohibited

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

Nitroglycerin mixture, desensitized, solid, n.o.s. with more than 2 percent but not more than 10 percent nitroglycerin, by mass — Postal shipping restrictions by item category


**Item category:** Nitroglycerin, solution in alcohol, with more than 1 percent but not more than 10 percent nitroglycerin

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 1.1D, UN0144, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitroglycerin, solution in alcohol, with more than 1 percent but not more than 10 percent nitroglycerin 1.1D UN0144 II Prohibited Prohibited

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

Nitroglycerin, solution in alcohol, with more than 1 percent but not more than 10 percent nitroglycerin — Postal shipping restrictions by item category


**Item category:** Nitroglycerin, solution in alcohol, with more than 1 percent but not more than 5 percent nitroglycerin

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 3, UN3064, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitroglycerin, solution in alcohol, with more than 1 percent but not more than 5 percent nitroglycerin 3 UN3064 II Prohibited Prohibited

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

Nitroglycerin, solution in alcohol, with more than 1 percent but not more than 5 percent nitroglycerin — Postal shipping restrictions by item category


**Item category:** Nitroglycerin, solution in alcohol, with not more than 1 percent nitroglycerin

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 3, UN1204, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitroglycerin, solution in alcohol, with not more than 1 percent nitroglycerin 3 UN1204 II Prohibited Prohibited

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

Nitroglycerin, solution in alcohol, with not more than 1 percent nitroglycerin — Postal shipping restrictions by item category


**Item category:** Nitroguanidine nitrate

**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.

> Nitroguanidine nitrate Forbidden Prohibited Prohibited Prohibited Prohibited

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

Nitroguanidine nitrate — Postal shipping restrictions by item category


**Item category:** Nitroguanidine or Picrite, dry or wetted with less than 20 percent water, by mass

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 1.1D, UN0282, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitroguanidine or Picrite, dry or wetted with less than 20 percent water, by mass 1.1D UN0282 II Prohibited Prohibited

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

Nitroguanidine or Picrite, dry or wetted with less than 20 percent water, by mass — Postal shipping restrictions by item category


**Item category:** Nitroguanidine, wetted or Picrite, wetted with not less than 20 percent water, by mass

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 4.1, UN1336, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitroguanidine, wetted or Picrite, wetted with not less than 20 percent water, by mass 4.1 UN1336 I Prohibited Prohibited

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

Nitroguanidine, wetted or Picrite, wetted with not less than 20 percent water, by mass — Postal shipping restrictions by item category


**Item category:** Nitrohydrochloric acid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 8, UN1798, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrohydrochloric acid 8 UN1798 I Prohibited Prohibited

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

Nitrohydrochloric acid — Postal shipping restrictions by item category


**Item category:** Nitromannite (dry)

**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.

> Nitromannite (dry) Forbidden Prohibited Prohibited Prohibited Prohibited

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

Nitromannite (dry) — Postal shipping restrictions by item category


**Item category:** Nitronaphthalene

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 4.1, UN2538, packing group III; domestic mail air: Prohibited; domestic mail surface: 4A

> Nitronaphthalene 4.1 UN2538 III Prohibited 4A

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

Nitronaphthalene — Postal shipping restrictions by item category


**Item category:** Nitropropanes

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2608, packing group III; domestic mail air: Prohibited; domestic mail surface: 3A

> Nitropropanes 3 UN2608 III Prohibited 3A

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

Nitropropanes — Postal shipping restrictions by item category


**Item category:** Nitrostarch, dry or wetted with less than 20 percent water, by mass

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 1.1D, UN0146, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrostarch, dry or wetted with less than 20 percent water, by mass 1.1D UN0146 II Prohibited Prohibited

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

Nitrostarch, dry or wetted with less than 20 percent water, by mass — Postal shipping restrictions by item category


**Item category:** Nitrostarch, wetted with not less than 20 percent water, by mass

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 4.1, UN1337, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrostarch, wetted with not less than 20 percent water, by mass 4.1 UN1337 I Prohibited Prohibited

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

Nitrostarch, wetted with not less than 20 percent water, by mass — Postal shipping restrictions by item category


**Item category:** Nitrosugars (dry)

**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.

> Nitrosugars (dry) Forbidden Prohibited Prohibited Prohibited Prohibited

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

Nitrosugars (dry) — Postal shipping restrictions by item category


**Item category:** Nitrosyl chloride

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 2.3, UN1069, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrosyl chloride 2.3 UN1069 n/a Prohibited Prohibited

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

Nitrosyl chloride — Postal shipping restrictions by item category


**Item category:** Nitrosylsulfuric acid, liquid

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 8, UN2308, packing group II; domestic mail air: 8A; domestic mail surface: 8A

> Nitrosylsulfuric acid, liquid 8 UN2308 II 8A 8A

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

Nitrosylsulfuric acid, liquid — Postal shipping restrictions by item category


**Item category:** Nitrosylsulfuric acid, solid

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 8, UN3456, packing group II; domestic mail air: 8A; domestic mail surface: 8A

> Nitrosylsulfuric acid, solid 8 UN3456 II 8A 8A

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

Nitrosylsulfuric acid, solid — Postal shipping restrictions by item category


**Item category:** Nitrotoluenes, liquid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN1664, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrotoluenes, liquid 6.1 UN1664 II Prohibited Prohibited

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

Nitrotoluenes, liquid — Postal shipping restrictions by item category


**Item category:** Nitrotoluenes, solid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN3446, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrotoluenes, solid 6.1 UN3446 II Prohibited Prohibited

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

Nitrotoluenes, solid — Postal shipping restrictions by item category


**Item category:** Nitrotoluidines (mono)

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 6.1, UN2660, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> Nitrotoluidines (mono) 6.1 UN2660 III 6A 6A

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

Nitrotoluidines (mono) — Postal shipping restrictions by item category


**Item category:** Nitrotriazolone or NTO

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 1.1D, UN0490, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrotriazolone or NTO 1.1D UN0490 II Prohibited Prohibited

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

Nitrotriazolone or NTO — Postal shipping restrictions by item category


**Item category:** Nitrous oxide, refrigerated liquid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 2.2, UN2201, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitrous oxide, refrigerated liquid 2.2 UN2201 n/a Prohibited Prohibited

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

Nitrous oxide, refrigerated liquid — Postal shipping restrictions by item category


**Item category:** Nitrous oxide

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 2.2, UN1070, packing group n/a; domestic mail air: 2B; domestic mail surface: 2B

> Nitrous oxide 2.2 UN1070 n/a 2B 2B

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

Nitrous oxide — Postal shipping restrictions by item category


**Item category:** Nitroxylenes, liquid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN1665, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitroxylenes, liquid 6.1 UN1665 II Prohibited Prohibited

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

Nitroxylenes, liquid — Postal shipping restrictions by item category


**Item category:** Nitroxylenes, solid

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 6.1, UN3447, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nitroxylenes, solid 6.1 UN3447 II Prohibited Prohibited

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

Nitroxylenes, solid — Postal shipping restrictions by item category


**Item category:** Nonanes

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN1920, packing group III; domestic mail air: Prohibited; domestic mail surface: 3A

> Nonanes 3 UN1920 III Prohibited 3A

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

Nonanes — Postal shipping restrictions by item category


**Item category:** nonhazardous liquids

**Carrier:** USPS

**Restriction type:** allowed

**Scope:** domestic mail

**Conditions:** Liquids that are nonhazardous are mailable provided they are properly packaged

> Liquids that are nonhazardous (i.e., not regulated as hazardous materials) are mailable provided they are properly packaged as specified in 451.3

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

nonhazardous liquids — Postal shipping restrictions by item category


**Item category:** nonnarcotic prescription medicines

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** domestic mail

**Conditions:** Only a pharmacist, medical practitioner, or other authorized dispenser may mail nonnarcotic prescription medications to patients under their care

> Only a pharmacists, medical practitioners, or other authorized dispensers may mail nonnarcotic prescription medications to patients under their care.

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

nonnarcotic prescription medicines — Postal shipping restrictions by item category


**Item category:** nonprescription medicines (OTC drugs)

**Carrier:** USPS

**Restriction type:** allowed

**Scope:** domestic mail

**Conditions:** OTC drugs that do not contain controlled substances are mailable; mailer must comply with all applicable federal, state, and local laws

> Over-the-Counter (OTC) Drugs: Medicines that can be obtained without a prescription, such as patent medicines, aspirin, antiseptics, cold remedies, diet pills, and cosmetic medicines that do not contain a controlled substance and are not poisonous drugs or medicines.

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

nonprescription medicines (OTC drugs) — Postal shipping restrictions by item category

carrier, conditions, item_category, scope


**Item category:** Nonspillable wet batteries (UN2800)

**Carrier:** USPS

**Restriction type:** restricted

**Scope:** all mail

**Conditions:** Acceptable if completely sealed to prevent liquid corrosive from spilling; must follow Packaging Instruction 8B

> Nonspillable Wet Batteries (UN2800): Acceptable if completely sealed to prevent the liquid corrosive from spilling during handling

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

Nonspillable wet batteries (UN2800) — Postal shipping restrictions by item category


**Item category:** Nonyltrichlorosilane

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 8, UN1799, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Nonyltrichlorosilane 8 UN1799 II Prohibited Prohibited

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

Nonyltrichlorosilane — Postal shipping restrictions by item category


**Item category:** o-Dichlorobenzene

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 6.1, UN1591, packing group III; domestic mail air: 6A; domestic mail surface: 6A

> o-Dichlorobenzene 6.1 UN1591 III 6A 6A

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

o-Dichlorobenzene — Postal shipping restrictions by item category


**Item category:** Octadecyltrichlorosilane

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 8, UN1800, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Octadecyltrichlorosilane 8 UN1800 II Prohibited Prohibited

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

Octadecyltrichlorosilane — Postal shipping restrictions by item category


**Item category:** Octadiene

**Carrier:** USPS

**Restriction type:** restricted

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

**Conditions:** Hazard class 3, UN2309, packing group II; domestic mail air: Prohibited; domestic mail surface: 3A

> Octadiene 3 UN2309 II Prohibited 3A

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

Octadiene — Postal shipping restrictions by item category


**Item category:** Octafluorobut-2-ene or Refrigerant gas R 1318

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 2.2, UN2422, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Octafluorobut-2-ene or Refrigerant gas R 1318 2.2 UN2422 n/a Prohibited Prohibited

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

Octafluorobut-2-ene or Refrigerant gas R 1318 — Postal shipping restrictions by item category


**Item category:** Octafluorocyclobutane, or Refrigerant gas RC 318

**Carrier:** USPS

**Restriction type:** prohibited

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

**Conditions:** Hazard class 2.2, UN1976, packing group n/a; domestic mail air: Prohibited; domestic mail surface: Prohibited

> Octafluorocyclobutane, or Refrigerant gas RC 318 2.2 UN1976 n/a Prohibited Prohibited

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

Octafluorocyclobutane, or Refrigerant gas RC 318 — Postal shipping restrictions by item category