Postal shipping restrictions by item category
What item categories each postal carrier prohibits, restricts, or allows, with the conditions that apply. Covers USPS (domestic US) and Royal Mail / Post Office (UK domestic and international).
Records310
Sources2
Verified2026-08-03
Review by2027-08-03
LicenceFacts extracted from public government and postal service web pages; not a reproduction of the original text
7 records where two or more sources state different values. Both sides are reproduced on the record page, each with its own source and quote.
The data
| Item category | Carrier | Restriction type | Scope | Conditions |
|---|---|---|---|---|
| Spare (uninstalled) lithium ion batteries | Airlines (all US carriers) | carry-on only | passenger air travel | Must be in carry-on baggage only; if carry-on is checked at gate or planeside, batteries must be removed and kept with passenger in cabin; battery terminals must be protected from short circuit; size limit 100 Wh per battery (up to 160 Wh with airline approval, max 2 batteries); prohibited if carried for resale/distribution |
| Spare (uninstalled) lithium metal batteries | Airlines (all US carriers) | carry-on only | passenger air travel | Must be in carry-on baggage only; if carry-on is checked at gate or planeside, batteries must be removed and kept with passenger in cabin; battery terminals must be protected from short circuit; size limit 2 grams of lithium content per battery (up to 8 grams with airline approval, max 2 batteries); prohibited if carried for resale/distribution |
| Batteries carried for further sale or distribution | FAA (air transport) | prohibited | aircraft (all baggage) | Batteries carried for further sale or distribution (vendor samples, etc.) are prohibited. |
| Damaged or recalled batteries and battery-powered devices | FAA (air transport) | prohibited | aircraft (all baggage) | Must not be carried aboard an aircraft if likely to create sparks or generate a dangerous evolution of heat. |
| Spare lithium ion batteries (101–160 Wh) | FAA (air transport) | restricted | carry-on baggage | With airline approval only; limited to two spare larger lithium ion batteries exceeding 101–160 Wh. |
| Spare lithium metal batteries (exceeding 2-8 grams) | FAA (air transport) | restricted | carry-on baggage | With airline approval only; limited to two spare Lithium metal batteries exceeding 2-8 grams. |
| Lithium-ion (PI 965) cells or batteries packed alone — Section IA | IATA (air) | restricted | international air transport | Highest restriction tier. Applies to lithium ion cells/batteries packed alone that exceed the Section IB quantity/watt-hour thresholds. Full IATA DGR compliance required including UN specification packaging, all labelling, documentation, and biennial training. No exceptions. |
| Lithium-ion (PI 965) cells or batteries packed alone — Section IB | IATA (air) | restricted | international air transport | Applies to lithium ion cells/batteries at or below threshold watt-hour content and within the quantity limit in Table 965-IB. Full IATA DGR compliance required (including initial and biennial training) EXCEPT that UN specification packaging is not required. Effective March 31, 2022 — Section II was removed. |
| Lithium metal (PI 968) cells or batteries packed alone — Section IB | IATA (air) | restricted | international air transport | Applies to lithium metal cells/batteries at or below lithium content threshold and within quantity limit in Table 968-IB. Full IATA DGR compliance required (biennial training mandatory) EXCEPT UN specification packaging not required. Effective March 31, 2022. |
| Lithium metal (PI 968) cells or batteries packed alone — Section II | IATA (air) | allowed | international air transport | REMOVED effective March 31, 2022. Section II previously exempted small lithium metal cells/batteries packed alone from full regulation (no training, no specification packaging). This exception no longer exists. |
| Lithium ion batteries contained in equipment (UN 3481) — recommended 2025 | IATA air transport | restricted | air transport | IATA DGR recommends state of charge not exceeding 30%, or an indicated battery capacity not exceeding 25%. |
| Lithium ion batteries packed alone (UN 3480) | IATA air transport | restricted | air transport | Must be offered for transport at a state of charge not exceeding 30% of their rated design capacity. |
| Lithium ion batteries packed with equipment (UN 3481) — cells >2.7 Wh | IATA air transport | restricted | air transport | Starting January 1, 2026, must be offered for transport at a state of charge not exceeding 30% of their rated design capacity. |
| Lithium ion batteries packed with equipment (UN 3481) — recommended 2025 | IATA air transport | restricted | air transport | IATA DGR recommends shipments be offered for transport at a state of charge not exceeding 30% of their rated design capacity. |
| Vehicle, lithium ion battery powered (UN 3556) — battery >100 Wh | IATA air transport | restricted | air transport | Starting January 1, 2026, must be offered for transport at a state of charge not exceeding 30% or an indicated battery capacity not exceeding 25%. |
| Batteries | Royal Mail / Post Mail | allowed | UK & International | Batteries must comply with Special Provision 238 of the UN Recommendations on the Transport of Dangerous Goods, Model Regulations (please check with the manufacturer or distributor) |
| Act 1976 (including certain venomous spiders) | Royal Mail / Post Office | prohibited | UK & International | |
| Aerosols | Royal Mail / Post Office | prohibited | International | International – not allowed in the mail |
| Alcohol less than 24% ABV | Royal Mail / Post Office | allowed | UK & International | The sender's name and return address must be clearly visible on the outer packaging |
| Alcoholic beverages and liquids containing less than 24% alcohol by volume | Royal Mail / Post Office | restricted | UK & International | Volume should not exceed 1 litre per item; must wrap in polythene and seal with tape; mark as FRAGILE when sending glass bottles |
| Alcoholic beverages and liquids containing less than 24% alcohol by volume (ABV) | Royal Mail / Post Office | restricted | UK & International | These items must be presented at a Post Office® counter |
| Alcoholic beverages and liquids containing more than 24% but not more than 70% alcohol by volume (ABV) | Royal Mail / Post Office | restricted | UK | These items must be presented at a Post Office® counter |
| Alcoholic beverages and liquids containing more than 70% alcohol by volume (ABV) | Royal Mail / Post Office | prohibited | International | International – not allowed in the mail |
| Ammunition | Royal Mail / Post Office | prohibited | International | not allowed in the mail |
| Asbestos | Royal Mail / Post Office | prohibited | International | not allowed in the mail |
| Balloons filled with non-flammable gases | Royal Mail / Post Office | allowed | UK | ensure adequate cushioning material and place in a suitable rigid outer container |
| Batteries | Royal Mail / Post Office | restricted | UK | The sender's name and return address must be clearly visible on the outer packaging |
| Batteries (dangerous goods, not connected to device) | Royal Mail / Post Office | prohibited | UK & International | Batteries classified as dangerous goods including wet spillable lead acid, used alkaline metal, NiMH, NiCd, zinc-air, solo lithium batteries, power banks and damaged batteries are not allowed |
| Batteries (new alkaline, NiMH, NiCd, zinc-air) | Royal Mail / Post Office | restricted | UK & International | Must be new and sent unopened in their original retail packaging; surround with cushioning material |
| Batteries (new lithium, not with device) | Royal Mail / Post Office | prohibited | UK & International | New and used lithium batteries when not sent with or connected to an electronic device including power banks are not allowed |
| Biological substances (Category B) | Royal Mail / Post Office | restricted | UK | The sender's name and return address must be clearly visible on the outer packaging |
| Bladed items | Royal Mail / Post Office | restricted | UK | Prohibited from all Parcelforce Worldwide services |
| Car parts | Royal Mail / Post Office | restricted | UK | Car parts, panels, doors, bumpers and bonnets are prohibited using Parcelforce Worldwide services |
| Christmas crackers | Royal Mail / Post Office | restricted | UK & International | Can only be sent in their complete made-up form and in their original retail packaging |
| Clinical and medical waste | Royal Mail / Post Office | prohibited | UK | not allowed in the mail |
| Controlled drugs and narcotics | Royal Mail / Post Office | prohibited | UK | not allowed in the mail |
| Corrosives | Royal Mail / Post Office | prohibited | UK | not allowed in the mail |
| Counterfeit currency, bank notes and postage stamps | Royal Mail / Post Office | prohibited | UK & International | except copies of old denominations, which are now obsolete and worthless except for collectable value and cannot be passed as tender |
| Dead insects, sent as collectables | Royal Mail / Post Office | allowed | UK | Dead insects, sent as collectables, are allowed |
| Dry ice | Royal Mail / Post Office | prohibited | UK & International | Not allowed in the mail |
| Electronic devices with lithium batteries (battery connected to device) | Royal Mail / Post Office | restricted | UK & International | No more than four cells or two batteries installed; Wh rating must not exceed 20Wh per cell or 100Wh per battery; must be presented at a Post Office counter |
| Electronic devices with lithium batteries (battery not connected) | Royal Mail / Post Office | restricted | UK | Maximum number of lithium batteries is minimum required to power device plus two spares; Wh rating must not exceed 20Wh per cell or 100Wh per battery; prohibited internationally |
| Environmental Hazardous Substances | Royal Mail / Post Office | restricted | UK | Pack in a leak-proof or sift-proof inner and protect by cushioning material in rigid outer packaging |
| Environmental Waste | Royal Mail / Post Office | prohibited | UK | UK – not allowed in the mail |
| Explosives | Royal Mail / Post Office | prohibited | UK | UK – not allowed in the mail |
| Firearms | Royal Mail / Post Office | restricted | UK | Sender's name and address must be visible on the parcel |
| Flammable liquids | Royal Mail / Post Office | prohibited | UK | not allowed in the mail |
| Flammable solids | Royal Mail / Post Office | prohibited | UK | not allowed in the mail |
| Frozen water | Royal Mail / Post Office | prohibited | UK | not allowed in the mail |
| Frozen water and dry ice | Royal Mail / Post Office | prohibited | UK & International | Must be suitably sealed to prevent leakage or tainting of other items such as in sealed vacuum packs |
| Gases (flammable, non-flammable, toxic, compressed) | Royal Mail / Post Office | prohibited | UK & International | Not allowed in the mail; includes new, used and empty gas cylinders, fire extinguishers, scuba tanks |
| Gases, including flammable, non-flammable, toxic and compressed gases | Royal Mail / Post Office | prohibited | UK | not allowed in the mail |
| Goods made in foreign prisons | Royal Mail / Post Office | prohibited | UK | not allowed in the mail |
| Guns for sporting use | Royal Mail / Post Office | allowed | UK | allowed in the mail, see restrictions and packaging guidelines below |
| Human or animal ashes | Royal Mail / Post Office | restricted | UK & International | The sender's name and return address must be clearly visible on the outer packaging |
| Lighters | Royal Mail / Post Office | restricted | UK & International | Lighters considered to contain residual fuel may be disposed of |
| Lighters and refills containing flammable liquid or gas | Royal Mail / Post Office | prohibited | UK & International | International – not allowed in the mail |
| Lighters (empty, new or unused) | Royal Mail / Post Office | restricted | UK & International | Must be unopened and in their original retail packaging; lighters considered to contain residual fuel may be disposed of |
| Liquids not classified as dangerous goods | Royal Mail / Post Office | restricted | UK | Customers posting via Parcelforce Worldwide, maximum 5 litres per container, must be sent using express48 |
| Liquids under 1 litre | Royal Mail / Post Office | restricted | UK & International | Mark as "FRAGILE" when sending glass bottles |
| Lithium Batteries | Royal Mail / Post Office | restricted | UK & International | The equipment containing cells or batteries must be packed in strong rigid packaging and must be secured against movement within the outer packaging and packed to prevent accidental activation |
| Live creatures, insects and invertebrates | Royal Mail / Post Office | restricted | UK | The sender's name and address must be clearly visible on the outer packaging |
| Lottery tickets | Royal Mail / Post Office | prohibited | UK | UK – not allowed in the mail (except UK lottery tickets) |
| Magnetised material | Royal Mail / Post Office | allowed | UK & International | Should be wrapped in soft packaging at least 2cm thick around each item |
| Matches | Royal Mail / Post Office | prohibited | UK & International | Not allowed in the mail, including safety matches and windproof matches |
| Medicines | Royal Mail / Post Office | restricted | UK & International | Sender's name and address must be visible on the parcel |
| Nail varnish, polish or gel | Royal Mail / Post Office | allowed | UK | These items must be presented at a Post Office® counter |
| Obscene publications and unlawful indecent images | Royal Mail / Post Office | prohibited | UK & International | |
| Oxidising materials or organic peroxides | Royal Mail / Post Office | prohibited | UK & International | |
| Paints (solvent-based) | Royal Mail / Post Office | prohibited | UK & International | Not allowed in the mail |
| Paints (water-based) | Royal Mail / Post Office | restricted | UK & International | Volume per item should not exceed 150ml; must be securely closed and placed in a leak-proof liner |
| Paints, wood varnishes and enamels | Royal Mail / Post Office | prohibited | UK | |
| Perfumes and aftershaves | Royal Mail / Post Office | allowed | UK | These items must be presented at a Post Office® counter |
| Perishable items | Royal Mail / Post Office | allowed | UK | Packages must be clearly labelled "PERISHABLE" |
| Plants and seeds for planting | Royal Mail / Post Office | allowed | UK destinations | UK destinations - Allowed in the mail, with restrictions and packaging guidelines below. Note: from 2 June 2025 plants and seeds are prohibited when sent from Great Britain to Northern Ireland |
| Poisons, toxic liquids, solids and gases | Royal Mail / Post Office | prohibited | UK & International | International – not allowed in the mail |
| Prescription medicines and drugs sent for scientific or medical purposes | Royal Mail / Post Office | allowed | UK & International | May only be sent by, or at the specific request of, a qualified medical practitioner, registered dental practitioner, veterinary surgeon, registered nurse or a recognised laboratory or institution |
| Radioactive materials and samples | Royal Mail / Post Office | allowed | UK & International | The sender's name and return address must be clearly visible on the outer packaging |
| Sharp objects | Royal Mail / Post Office | allowed | International & UK | The sender's name and return address must be clearly visible on the outer packaging |
| Soil samples | Royal Mail / Post Office | allowed | UK | Soil samples sent for analysis are permitted provided they are packaged so that any leaks and spills are contained in the outer packaging |
| substances and injure health | Royal Mail / Post Office | prohibited | UK | |
| Tickets and related advertisements for illegal lotteries | Royal Mail / Post Office | prohibited | UK | UK – not allowed in the mail |
| Vaccines | Royal Mail / Post Office | restricted | UK | The vaccines must be securely closed and placed in a leak-proof liner such as a sealed polythene bag (for liquids) or a sift-proof container (for solids) |
| Water-based paint | Royal Mail / Post Office | prohibited | UK & International | |
| Water-based paints, wood varnishes and enamels | Royal Mail / Post Office | allowed | International & UK | The sender's name and return address must be clearly visible on the outer packaging |
| Weapons | Royal Mail / Post Office | prohibited | UK & International | Weapons (including Section 5 firearms, CS gas and pepper sprays, flick knives and other knives that are banned under UK laws, tasers and stun guns) |
| Lithium batteries (100 watt hours or less) in a device | TSA (air transport screening) | allowed | carry-on bags and checked bags | Carry On Bags: Yes. Checked Bags: Yes (Special Instructions). Lithium ion batteries limited to a rating of 100 watt hours (Wh) per battery. |
| Spare (uninstalled) lithium ion and lithium metal batteries | TSA (air transport screening) | restricted | carry-on baggage only | Must be carried in carry-on baggage only. Lithium metal limited to 2 grams per battery; lithium ion limited to 100 watt hours (Wh) per battery. |
| Acetic acid (UN2790) | USPS | restricted | domestic mail via air or surface transportation | Mailable if meets Limited Quantity requirements, contains less than 80% acid, and does not exceed 1 pint; Packaging Instruction 8A must be followed |
| Acetone (UN1090), Benzene (UN1114), Hexane(s) (UN1208) | USPS | prohibited | all mail | Nonmailable unless diluted with less flammable or nonflammable materials sufficient to raise flashpoint to 20 F or higher |
| Adhesives and cements (UN1133) | USPS | restricted | domestic mail via surface transportation only | Mailable only if qualifies as Limited Quantity surface material and meets conditions; Packaging Instruction 3A or 3B as applicable |
| Aerosol deodorant | USPS | restricted | domestic US | Classified as flammable aerosol. Requires hazmat declaration and rigid outer packaging. $50 noncompliance fee if undeclared, effective July 12, 2026. |
| Aerosol paint products (flammable compressed gas) | USPS | restricted | domestic mail via surface transportation only | Acceptable via surface transportation only if qualifies as Limited Quantity ground material and meets quantity limitations and applicable packaging requirements |
| Aerosol sprays | USPS | hazmat declaration required | online marketplace seller shipments (Poshmark) | 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 |
| Aerosolssources differ | USPS | allowed | domestic | Make sure you read about the specific rules and restrictions for sending mailable gases. |
| Aerosols (all types regardless of contents — hairspray, deodorant, cooking spray, spray paint, dry shampoo, aerosol sunscreen) | USPS | restricted | domestic US | Any aerosol is classified as pressurized container. Requires hazmat declaration. Cannot be shipped in poly mailers. $50 noncompliance fee if undeclared, effective July 12, 2026. |
| Air Bags | USPS | prohibited | domestic | Completely forbidden in the U.S. mail |
| air guns | USPS | allowed | domestic mail | Air guns are not regulated as firearms unless manufactured with frames or receivers of an actual firearm; devices that expel projectiles using compressed air or gas including paintball and pellet guns |
| air guns - high muzzle velocity | USPS | restricted | domestic mail | Air guns with muzzle velocity of 400 or more feet per second must include Adult Signature service; mailers responsible for compliance with all applicable state and local regulations |
| Alcoholic Beverages | USPS | prohibited | domestic | Beer, wine, and liquor may not be sent through the mail, except in limited circumstances. |
| All flammable liquids with flashpoint of 20 F (-7 C) or below | USPS | prohibited | all mail | All flammable liquids with flashpoint at or below 20 F are prohibited from mailing |
| Ammunition | USPS | prohibited | domestic | Completely forbidden in the U.S. mail |
| Articles made from natural or depleted uranium or natural thorium (UN2909) | USPS | restricted | domestic mail via surface transportation | Mailable if activity does not exceed limits in Exhibit 347.22; classified as excepted package per 49 CFR 172.101; must follow Packaging Instruction 7A |
| Audible fire alarm systems powered by compressed gas | USPS | restricted | domestic mail via surface transportation | Acceptable via surface transportation if comply with conditions in Packaging Instruction 2E |
| Batteries with liquid electrolyte (UN2794, UN2795) | USPS | prohibited | all mail | Nonmailable; includes automobile lead acid batteries except for non-spillable type |
| Biological products exceeding 4 liters or 4 kg containing Category A | USPS | prohibited | all mail | Biological products, cultures, or specimens known or suspected to contain Category A infectious substance, or exceeding 4 liters/4 kg limits, are nonmailable |
| Biological products or medical preparations in nonrefillable metal containers | USPS | restricted | domestic surface mail only | Nonflammable solutions accepted for domestic surface mail only if they comply with Packaging Instruction 2F |
| Blood for transfusion containing Category A infectious substance | USPS | prohibited | all mail | Blood collected for transfusion and known or suspected to contain a Category A infectious substance is nonmailable |
| Butane (UN1011) — Division 2.1 flammable gas | USPS | restricted | domestic mail via surface transportation only | Mailable via surface transportation as Limited Quantity material; must comply with quantity limits and Packaging Instruction 2A |
| Candles | USPS | hazmat declaration required | seller shipments (Etsy) | May have special shipping requirements under USPS hazardous materials rules; $50 noncompliance fee for undeclared or improperly prepared hazardous materials effective July 12 2026 |
| Canned heat (Sterno) | USPS | restricted | domestic mail via surface transportation | Mailable if qualifies as Limited Quantity surface material and meets quantity limitations and packaging requirements; Packaging Instruction 3A must be followed |
| Carbonated beverages | USPS | allowed | all domestic mail | Not regulated as hazardous materials; mailable without restriction but must be properly packaged per DMM 601 |
| Category A infectious substances (UN2814, UN2900) | USPS | prohibited | all mail including international | Category A infectious substances (capable of causing permanent disability or life-threatening disease in healthy humans/animals) are nonmailable |
| Category B infectious substances (UN3373) | USPS | restricted | domestic mail and limited international mail | Mailable only when intended for medical, veterinary, research, or public health lab use; must be properly prepared; domestic mailing requires Priority Mail or Priority Mail Express; international requires written approval from director Product Classification |
| Chlorine dioxide hydrate, frozen | USPS | prohibited | all mail | Nonmailable Division 5.1 oxidizing substance |
| Cigarette lighters charged with fuel (NA1057) | USPS | prohibited | all mail | Lighters charged with fuel and having an ignition system are nonmailable; may seek DOT approval number for mailability ruling |
| cigarettes | USPS | restricted | all domestic mail | Any roll of tobacco wrapped in paper or any substance not containing tobacco, or roll of tobacco wrapped in substance containing tobacco likely to be purchased as a cigarette; includes roll-your-own tobacco, excludes cigars |
| Cigarettes, Cigars, & Tobacco | USPS | restricted | domestic | Cigarettes and smokeless tobacco are restricted items and can only be mailed in limited circumstances. Cigars may be mailed domestically. |
| Cleaning agents and solvents (flammable liquid) | USPS | restricted | domestic mail via surface transportation | Mailable if qualifies as Limited Quantity surface material and meets conditions; Packaging Instruction 3A must be followed |
| Combustible liquids — domestic air | USPS | restricted | domestic mail via air transportation | Mailable if qualify as ID8000 materials and meet criteria; Packaging Instruction 3B must be followed |
| Combustible liquids — domestic surface | USPS | restricted | domestic mail via surface transportation | Mailable if qualify as Limited Quantity and consumer commodity materials and meet criteria; Packaging Instruction 3B must be followed |
| Combustible Liquids (Hazard Class 3) | USPS | restricted | Domestic Mail via Air Transportation (as ID8000) or Surface Transportation (as Limited Quantity); prohibited International | Via air, mailable if they qualify as ID8000 materials per 335 and meet criteria in Exhibit 343.22. Via surface, mailable if they qualify as Limited Quantity and consumer commodity materials per 343.22. Prohibited in international mail. |
| Combustible liquids — international mail | USPS | prohibited | international mail | All combustible liquids are prohibited from international mail |
| Common household dry-cell batteries (AA, AAA, C, D, etc.) | USPS | allowed | all mail | Generally not regulated as hazardous materials; mailable subject to DMM 601 packaging requirements |
| Compact fluorescent lamps and similar devices with small amounts of mercury (UN3506) | USPS | restricted | domestic mail via air or surface transportation | Mailable if each device contains 100 mg or less of mercury and each mailpiece contains no more than 1 gram of mercury total; follow Packaging Instruction 8C |
| controlled substances - DEA-registered mailers | USPS | allowed | domestic mail - between DEA-registered parties | Controlled substances are acceptable in domestic mail only when both mailer and addressee are registered with DEA or are exempted from DEA registration such as military, civil defense, and law enforcement personnel performing official duties |
| controlled substances - Schedule I-V | USPS | prohibited | all mail - when distribution is unlawful | If the distribution of a controlled substance is unlawful under 21 U.S.C. Section 801-971 or implementing regulations, mailing is also unlawful under 18 U.S.C. Section 1716 |
| Corrosive liquid mixtures qualifying as Limited Quantity — domestic | USPS | restricted | domestic mail via air or surface transportation | Mailable if 1 pint or less and contains 15% or less corrosive material; must meet Limited Quantity requirements |
| Corrosives (Hazard Class 8) — international mail | USPS | prohibited | international mail | All corrosives are prohibited from international mail |
| covered products (cigarettes, smokeless tobacco, ENDS) - general prohibition | USPS | prohibited | all mail - general public | The Postal Service will not accept, forward, or deliver packages it knows or reasonably believes to contain nonmailable covered products; seized and forfeited nonmailable covered products will be destroyed |
| covered products - seizure and forfeiture | USPS | prohibited | all mail | Nonmailable covered products deposited in the mail are subject to seizure and forfeiture; will be destroyed or retained by the federal government for crime detection, prosecution, or related investigations |
| Cremated Remainssources differ | USPS | allowed | domestic | Other Guidelines on Shipping & Packaging Cremated Remains |
| Damaged, defective, or recalled lithium batteries | USPS | prohibited | all mail | Prohibited unless approved by the director, Product Classification |
| Diesel fuel (NA1993) | USPS | restricted | domestic mail via surface transportation | Mailable if qualifies as Limited Quantity surface material and meets conditions; Packaging Instruction 3B must be followed |
| Division 2.1 Flammable Gases — domestic air | USPS | prohibited | domestic mail via air transportation | Division 2.1 flammable gases are prohibited from domestic air mail |
| Division 2.1 Flammable Gases — domestic surface | USPS | restricted | domestic mail via surface transportation | Generally permitted if qualifies as Limited Quantity surface material and meets quantity limits and packaging requirements |
| Division 2.2 Nonflammable Gases — domestic air | USPS | restricted | domestic mail via air transportation | Generally permitted if qualifies as ID8000 material and meets quantity limits and packaging requirements |
| Division 2.3 Toxic Gases — domestic air | USPS | prohibited | domestic mail via air transportation | Division 2.3 toxic gases are prohibited from domestic air mail |
| Division 2.3 Toxic Gases — domestic surface | USPS | prohibited | domestic mail via surface transportation | Division 2.3 toxic gases are prohibited from domestic surface mail |
| Division 6.1 toxic substances — international mail | USPS | prohibited | international mail | Division 6.1 toxic substances, poisons, and irritating materials are prohibited from international mail |
| Division 6.1 toxic substances qualifying as Limited Quantity/consumer commodity | USPS | restricted | domestic mail via air or surface transportation | Permitted when packaged under applicable requirements per Packaging Instruction 6A |
| Drain cleaner | USPS | restricted | domestic US | Classified as corrosive. Requires hazmat declaration. $50 noncompliance fee if undeclared, effective July 12, 2026. |
| drug paraphernalia | USPS | prohibited | all mail | Mailing drug paraphernalia is illegal under the Controlled Substances Act; any article deemed unlawful under the Controlled Substances Act is prohibited from mailing |
| Dry Ice | USPS | restricted | domestic | Packages containing dry ice must be packed in containers that permit the release of carbon dioxide gas. |
| Dry Ice (carbon dioxide solid) | USPS | restricted | Domestic Mail via Air Transportation (up to 5 pounds per mailpiece) or Surface Transportation; prohibited International | Via air, permitted in quantities of up to 5 pounds per mailpiece. Must comply with Packaging Instruction 9A in Appendix C. Dry ice is prohibited in international mail. |
| Dry ice — domestic air | USPS | restricted | domestic mail via air transportation | Permitted in quantities of up to 5 pounds per mailpiece; must comply with Packaging Instruction 9A |
| Dry ice — domestic surface | USPS | allowed | domestic mail via surface transportation | Dry ice is permitted via surface transportation; must comply with Packaging Instruction 9A |
| Dry ice — international mail | USPS | prohibited | international mail | Dry ice is prohibited from international mail |
| Dyes (UN2801, UN3147) | USPS | restricted | domestic mail via air or surface transportation | Acceptable if dyes qualify as Limited Quantity air or surface; must follow Packaging Instruction 8A |
| Electronic Nicotine Delivery System (ENDS) | USPS | restricted | all domestic mail | Any electronic device that delivers nicotine, flavor, or any other substance through an aerosolized solution; includes e-cigarettes, e-hookahs, e-cigars, vape pens, advanced refillable personal vaporizers, electronic pipes; includes any component, liquid, part, or accessory |
| Electronic tubes charged with gas | USPS | restricted | all mail | Mailable without restriction if volume does not exceed 30 cubic inches and tube is charged with gas at 35 psig or less; must be packed in strong outer containers |
| Electronics with a lithium battery | USPS | hazmat declaration required | commercial package shipments | 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) |
| Electronics with built-in lithium-ion batteries (phones, tablets, smartwatches, drones, cordless tools, toys with coin cells) | USPS | restricted | domestic US | Batteries packed with equipment (UN3481). Requires hazmat declaration at label creation. Cannot use poly mailers or padded envelopes — rigid cardboard packaging required. $7.50 handling fee on Priority Mail, $50 noncompliance fee if undeclared, effective July 12, 2026. |
| Electronics with lithium-ion batteries | USPS | hazmat declaration required | online marketplace seller shipments (Poshmark) | 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 |
| Empty compressed gas containers — unused/new | USPS | allowed | all mail | Mailable without restriction |
| Empty compressed gas containers — used | USPS | restricted | all mail | Mailable under same restrictions as when filled, because residual amounts of hazardous material might remain |
| Essential oils | USPS | hazmat declaration required | commercial package shipments | 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) |
| Ethanol-based flammable liquids or solids | USPS | restricted | domestic mail via air only | Mailable by domestic air only with prior written authorization from director, Product Classification; quantity and packaging limits apply based on ethanol concentration |
| Excessive dry ice — domestic air (over 5 lbs) | USPS | prohibited | domestic mail via air transportation | Dry ice exceeding 5 pounds per mailpiece is prohibited from air transport in domestic mail |
| Exempt human or animal specimens | USPS | restricted | all domestic mail | Not regulated as hazardous materials; must be triple-packaged per 346.327; outer packaging must be marked 'Exempt human specimen' or 'Exempt animal specimen' |
| Explosivessources differ | USPS | prohibited | domestic | Completely forbidden in the U.S. mail |
| Explosives (Hazard Class 1) — domestic air | USPS | prohibited | domestic mail via air transportation | All explosives are prohibited from domestic air mail |
| Explosives (Hazard Class 1) — domestic surface | USPS | prohibited | domestic mail via surface transportation | Generally prohibited; exceptions exist for Division 1.4S toy propellant devices and safety fuses with prior written approval |
| Explosives (Hazard Class 1) — international mail | USPS | prohibited | international mail | All explosives are prohibited from international mail |
| Fire extinguishers containing propellant explosives (UN0275, UN0276, UN0323, UN0381) | USPS | prohibited | all mail | Fire extinguishers that contain propellant explosives are prohibited from mailing |
| Fire Extinguishers (UN1044) — Division 2.2 nonflammable compressed gas | USPS | restricted | domestic mail | Mailable if do not contain methyl bromide gas mixtures, meet DOT container specifications, hold nonflammable/nonpoisonous/noncorrosive gas; only one extinguisher per mailpiece |
| Firearms | USPS | restricted | domestic | Even though unloaded rifles and shotguns are mailable, mailers must comply with applicable regulations. |
| firearms - handguns (including pistols and revolvers) | USPS | restricted | domestic mail | A firearm with a short stock designed to be held and fired by a single hand; includes pistols, revolvers, and firearms capable of being concealed on a person including short-barreled shotguns and short-barreled rifles |
| firearms - short-barreled shotgun or rifle | USPS | restricted | domestic mail | A shotgun with one or more barrels less than 18 inches long or a rifle with one or more barrels less than 16 inches long, or any such weapon modified to have an overall length less than 26 inches |
| Fireworks (Division 1.1, 1.2, 1.3, or 1.4) | USPS | prohibited | all mail | All types of fireworks are prohibited from mailing, including roman candles, skyrockets, firecrackers, and combinations |
| Flammable liquids (Hazard Class 3) — domestic air | USPS | prohibited | domestic mail via air transportation | All flammable liquids are prohibited from domestic air mail |
| Flammable liquids (Hazard Class 3) — international mail | USPS | prohibited | international mail | All flammable liquids are prohibited from international mail |
| Flammable liquids with flashpoint above 20 F — domestic surface | USPS | restricted | domestic mail via surface transportation only | Mailable if qualifies as Limited Quantity surface material and meets criteria; must follow Packaging Instruction 3A |
| Flammable liquids with flashpoint at or below 20 F — domestic surface | USPS | prohibited | domestic mail via surface transportation | Flammable liquids with a flashpoint at or below 20 F (-7 C) are prohibited from domestic surface mail |
| Flammable Nail Polishes | USPS | restricted | domestic | Some nail polishes may only be sent by ground transportation |
| Flammable or Combustible Paint | USPS | restricted | domestic | provided the material can qualify as a consumer commodity material or ORM-D (for surface only), and is sent within the quantity limitations and packaging requirements |
| Flammable solids (Hazard Class 4) — domestic air | USPS | prohibited | domestic mail via air transportation | All flammable solids are prohibited from domestic air mail |
| Flammable solids (Hazard Class 4) — international mail | USPS | prohibited | international mail | All flammable solids are prohibited from international mail |
| Flammable solids qualifying as Limited Quantity surface materials | USPS | restricted | domestic mail via surface transportation | Flammable solids that qualify as Limited Quantity surface materials are permitted in domestic mail via surface transportation |
| Foodstuffs and soaps in pressurized containers | USPS | restricted | domestic mail | Mailable if packaged in accordance with Packaging Instruction 2D |
| Fuel oil (NA1993) | USPS | restricted | domestic mail via surface transportation | Mailable if qualifies as Limited Quantity surface material and meets quantity limitations and packaging requirements; Packaging Instruction 3A or 3B as applicable |
| Fuming and spent sulfuric acids (UN1831, UN1832) | USPS | prohibited | all mail | Nonmailable corrosive |
| Fuses (except safety fuses Division 1.4S) | USPS | prohibited | all mail | All types of fuses except permitted safety fuses are prohibited from mailing |
| Gases (Hazard Class 2) — international mail | USPS | prohibited | international mail | All gases are prohibited from international mail |
| Gasoline | USPS | prohibited | domestic | Completely forbidden in the U.S. mail |
| Gasoline (UN1203) | USPS | prohibited | all mail | Gasoline is nonmailable under any circumstances |
| Glues | USPS | restricted | domestic | Some glues may only be sent by ground transportation. |
| Hairspray | USPS | hazmat declaration required | commercial package shipments | 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) |
| Hairspray (aerosol) | USPS | restricted | domestic US | Classified as flammable aerosol. Requires hazmat declaration and rigid outer packaging. Cannot be shipped in poly mailers or padded envelopes. $50 noncompliance fee if undeclared, effective July 12, 2026. |
| Hand Sanitizersources differ | USPS | restricted | domestic | It is prohibited to send these materials by International Mail including APO/FPO/DPO (military) destinations. |
| handguns - authorized military and law enforcement | USPS | allowed | domestic mail - to authorized military and law enforcement persons | May be mailed by licensed firearm manufacturers, dealers, importers, or authorized government agents only upon filing required affidavit or certificate, addressed to military officers, national guard officers, law enforcement officers, authorized Postal Service employees, or federal enforcement officers for official duties |
| handguns - between licensed FFL dealers | USPS | allowed | domestic mail - between licensed firearm manufacturers, dealers, and importers | Handguns may be mailed between licensed firearm manufacturers, dealers, and importers in customary trade shipments or for repairing or replacing parts |
| handguns - general prohibition | USPS | prohibited | domestic mail - general public | Handguns and other firearms capable of being concealed on the person are nonmailable unless mailed between authorized parties with required affidavit or statement |
| Hazardous Materials (HAZMAT) | USPS | restricted | domestic | Some HAZMAT can only be sent by ground transportation—it can’t go on airplanes. |
| hemp and hemp-based products including CBD | USPS | restricted | domestic mail only - prohibited in international mail | Hemp and hemp-based products with THC concentration not exceeding 0.3 percent are permitted domestically only when mailer complies with all applicable federal, state, and local laws; prohibited in all international mail including APO/FPO/DPO |
| Hemp Products (including CBD) | USPS | restricted | domestic | You cannot send hemp and hemp-derived products to international or military destinations. |
| honeybees | USPS | restricted | continental United States - surface transportation only | Must be free of disease; acceptable to mail only via surface transportation; mailpieces must be plainly marked with 'Live Bees' and 'Surface Only' or 'Surface Mail Only' |
| Hydrochloric acid (UN1789) | USPS | restricted | domestic mail via air or surface transportation | Acceptable only in solutions not exceeding 10% acid that qualify as Limited Quantity air or surface; Packaging Instruction 8A must be followed |
| Hydrofluoric acid (UN1790) | USPS | prohibited | all mail | Nonmailable corrosive |
| Hydrogen peroxide solution (8% or less) | USPS | restricted | all domestic mail | Regulated as hazardous material but must be prepared according to DMM 601.3.4 |
| Hydrogen peroxide solution (more than 20%) | USPS | prohibited | all mail | Nonmailable Division 5.1 oxidizing substance |
| Hydrogen peroxide solution (more than 8% but no more than 20%) | USPS | restricted | domestic mail | Permitted if can qualify as Limited Quantity air or Limited Quantity surface |
| Inks (flammable or combustible liquid) | USPS | restricted | domestic mail via surface transportation | Mailable if qualify as Limited Quantity surface material and meet requirements; primary receptacles must be cushioned with absorbent material; follow Packaging Instruction 3A or 3B as applicable |
| Inks, stains and varnishes | USPS | hazmat declaration required | commercial package shipments | 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) |
| intoxicating liquors | USPS | restricted | all domestic mail | Beverages with alcohol content of 0.5 percent or more by weight are taxable per Chapter 51 of the IRS Code and subject to mailability rules |
| intoxicating liquors - denatured flammable or combustible | USPS | restricted | domestic mail | If denaturing agents such as sodium bisulfate (a corrosive) or mercuric chloride (a poison) are used, substance must meet mailability requirements for Class 8 corrosive or Division 6.1 toxic substance; flammable or combustible contents must meet Class 3 requirements |
| intoxicating liquors - exempt federal/state agency mailings | USPS | allowed | between federal or state agency employees for official use | Intoxicating liquor is exempt from the prohibition when mailed between federal or state agency employees for official use such as testing purposes |
| intoxicating liquors - products not categorized as taxable alcoholic beverages | USPS | allowed | domestic mail | Product must comply with IRS and FDA regulations, not be classified as a taxable alcoholic beverage, not be poisonous, and not be flammable; examples include cold remedies, cooking wine, and mouthwash |
| Irritating materials — all types | USPS | prohibited | all mail | All irritating materials are nonmailable |
| Items containing lithium batteries | USPS | hazmat declaration required | seller shipments (Etsy) | May have special shipping requirements under USPS hazardous materials rules; $50 noncompliance fee for undeclared or improperly prepared hazardous materials effective July 12 2026 |
| knives and sharp instruments - general | USPS | restricted | all domestic mail | Sharp instruments include all sharp-pointed or sharp-edged implements such as knives, tools, ice picks, razor blades, stilettos, or similar devices |
| Laptop / phone batteries | USPS | restricted | domestic US | Lithium batteries packed with equipment require hazmat declaration. Must carry lithium battery mark (Class 9). $50 noncompliance fee if undeclared, effective July 12, 2026. |
| Latex paint and water-based paint (non-flammable, non-combustible) | USPS | allowed | all mail | Unrestricted and not regulated as a hazardous material; package per DMM 601 |
| Lighter fluid | USPS | restricted | domestic mail via surface transportation only | Permitted only via surface transportation if fluid qualifies as Limited Quantity surface material and is within quantity limitations and packaging requirements; Packaging Instruction 3A must be followed |
| Lighters / lighter refills | USPS | restricted | domestic US | Classified as flammable gas. Requires hazmat declaration. $50 noncompliance fee if undeclared, effective July 12, 2026. |
| Lighters with ignition elements containing liquid fuel or flammable gas | USPS | restricted | domestic mail via surface transportation only | Mailable via surface transportation only with DOT certification, PCSC director written authorization, specific packaging and labeling; shipping paper not required |
| Liquid Mercury | USPS | prohibited | US Mail | you must find another carrier |
| Liquid with flashpoint above 200 F (93 C) | USPS | allowed | all mail | Not regulated as hazardous material; mailable subject to general packaging requirements in DMM 601 provided it has no characteristics of another hazard class |
| Lithium Batteries | USPS | restricted | ground only | These devices must be marked on the outer packaging with the text, " Restricted Electronic Device " and " Surface Transportation Only ." |
| Lithium-ion (rechargeable) batteries without equipment (individual batteries) | USPS | prohibited | domestic mail via air transportation (except intra-Alaska) | Individual lithium-ion batteries without equipment are prohibited from domestic air transportation except intra-Alaska; mailable via surface only up to 5 lbs with proper markings |
| Lithium metal (non-rechargeable) batteries without equipment (individual batteries) | USPS | prohibited | domestic mail via air transportation | Individual lithium metal batteries without equipment are prohibited from domestic air transportation; mailable via surface only in sealed packaging up to 5 lbs with proper markings |
| Live Animals | USPS | restricted | domestic | Shipments of live animals, including poultry, reptiles, and bees, have very specific packaging requirements. |
| live day-old poultry - mailable types | USPS | allowed | domestic mail | Mailable types include chickens, ducks, emus, geese, guinea birds, partridges, pheasants (April through August only), quail, turkeys; all other types of live day-old poultry are nonmailable; must be no more than 24 hours old |
| live day-old poultry vaccinated with Newcastle disease (live virus) | USPS | prohibited | all domestic mail | Day-old poultry vaccinated with Newcastle disease (live virus) is nonmailable |
| live scorpions | USPS | restricted | continental United States only - surface transportation only | Scorpions are mailable only when sent for the purposes of medical research or the manufacturing of antivenin; must be sent by surface transportation within continental United States; must be properly packaged in double container system |
| Low-risk radioactive material (UN2910) — limited quantity excepted package | USPS | restricted | domestic mail via surface transportation | Mailable if activity does not exceed limits in Exhibit 347.22; classified as limited quantity excepted package per 49 CFR 172.101; must follow Packaging Instruction 7A |
| Magnetized materials — domestic surface transportation | USPS | allowed | domestic mail via surface transportation | Magnetized materials are not regulated as hazardous when transported via surface transportation |
| Magnetized materials with field strength exceeding 0.00525 gauss at 15 feet | USPS | prohibited | all domestic and international air transportation | Prohibited from air transportation under any circumstances |
| Marijuana | USPS | prohibited | domestic | Medical or otherwise prohibited; hemp/CBD is allowed but restricted |
| Medicines & Prescription Drugs | USPS | restricted | domestic | Prescription medications may only be mailed by Drug Enforcement Administration (DEA) registered distributors. |
| Mercury | USPS | prohibited | US Mail | Liquid mercury in any amount (and devices containing a visible amount of mercury) is prohibited from the US Mail, so you must find another carrier. |
| Mercury and mercury-containing devices (UN2809) | USPS | prohibited | all mail | Nonmailable; includes metallic mercury and thermometers, barometers, sphygmomanometers containing metallic mercury |
| Mercury Vapor Devices | USPS | restricted | domestic | These items are restricted, but mailable |
| Metal mercury (mercury thermometers, barometers, blood pressure monitors) | USPS | prohibited | all mail | USPS never allows metal mercury to be mailed |
| Miscellaneous hazardous materials (Hazard Class 9) — international mail | USPS | prohibited | international mail | All miscellaneous hazardous materials are prohibited internationally except certain magnetized materials and small consumer-type lithium batteries installed in their equipment |
| Model fuel for glow-plug engines | USPS | restricted | domestic mail via surface transportation only | Mailable only if qualifies as Limited Quantity surface material and meets quantity limitations and packaging requirements; Packaging Instruction 3A must be followed |
| Nail Polishsources differ | USPS | restricted | domestic | Flammable nail polishes may be mailed domestically if they are a consumer commodity; some may only be sent by ground |
| Nail polish and nail polish remover | USPS | hazmat declaration required | commercial package shipments | 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) |
| Nail polish remover | USPS | restricted | domestic US | Classified as flammable liquid (acetone). Requires hazmat declaration and compliant packaging. $50 noncompliance fee if undeclared, effective July 12, 2026. |
| Nitric acid (UN2031, UN2032) | USPS | prohibited | all mail | Nonmailable corrosive |
| nonhazardous liquids | USPS | allowed | domestic mail | Liquids that are nonhazardous are mailable provided they are properly packaged |
| nonnarcotic prescription medicines | USPS | restricted | domestic mail | Only a pharmacist, medical practitioner, or other authorized dispenser may mail nonnarcotic prescription medications to patients under their care |
| nonprescription medicines (OTC drugs) | USPS | allowed | domestic mail | OTC drugs that do not contain controlled substances are mailable; mailer must comply with all applicable federal, state, and local laws |
| Nonspillable wet batteries (UN2800) | USPS | restricted | all mail | Acceptable if completely sealed to prevent liquid corrosive from spilling; must follow Packaging Instruction 8B |
| odor-producing materials | USPS | prohibited | all domestic mail | Any matter that is a source of an obnoxious odor is nonmailable |
| Organic peroxides (Division 5.2) not qualifying as Limited Quantity | USPS | prohibited | all mail | Organic peroxides are nonmailable unless they qualify as Limited Quantity air or Limited Quantity surface |
| Oxidizing substances and organic peroxides (Hazard Class 5) — international mail | USPS | prohibited | international mail | All oxidizing substances and organic peroxides are prohibited from international mail |
| Oxidizing substances or organic peroxides qualifying as Limited Quantity | USPS | restricted | domestic mail via air or surface transportation | Permitted if qualify as Limited Quantity air or Limited Quantity surface materials |
| Oxygen, Compressed (UN1072) — Division 2.2 nonflammable gas | USPS | restricted | domestic mail | Mailable if qualifies as Limited Quantity material; must follow applicable packaging instructions |
| Oxygen, Refrigerated Liquid (UN1073) | USPS | prohibited | all mail | Prohibited from mailing under any circumstances |
| Packages with old hazmat markings or stickers (reused boxes) | USPS | hazmat noncompliance fee risk | online marketplace seller shipments (Poshmark) | Reused boxes with old hazmat labels will be flagged even if item inside is not hazardous; seller must remove or fully cover any existing hazmat markings before shipping |
| Paint | USPS | restricted | domestic | Flammable or combustible paint accepted if it qualifies as a consumer commodity; water-based paint is not regulated as hazardous |
| Paint and related items (UN1263) — lacquer, varnish, shellac, etc. | USPS | restricted | domestic mail via surface transportation | Mailable if qualify as Limited Quantity surface material and meet quantity limitations and packaging requirements; Packaging Instruction 3A or 3B as applicable |
| Paint thinner | USPS | restricted | domestic US | Classified as flammable liquid. Requires hazmat declaration. $50 noncompliance fee if undeclared, effective July 12, 2026. |
| Perchloric acid | USPS | prohibited | all mail | Nonmailable Division 5.1 oxidizing substance |
| Perfume | USPS | hazmat declaration required | online marketplace seller shipments (Poshmark) | 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 |
| Perfume / cologne | USPS | restricted | domestic US | Classified as flammable liquid due to alcohol content. Requires hazmat declaration and compliant packaging. $50 noncompliance fee if undeclared, effective July 12, 2026. |
| Perfume containing alcohol | USPS | restricted | domestic | may not be shipped internationally or mailed domestically using air transportation |
| Perfumessources differ | USPS | restricted | domestic, ground only | Perfume containing alcohol may not be shipped internationally or by air; may be shipped domestically by ground transportation |
| Perfumes and colognes | USPS | hazmat declaration required | commercial package shipments | 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) |
| Perishable Items | USPS | restricted | domestic | must be specially packaged and mailed so that they arrive before they begin to deteriorate |
| Pesticides, insecticides, herbicides with oral LD50 greater than 300 mg/kg (nonregulated) | USPS | restricted | all domestic mail | Mailable but must be packaged in rigid outer packaging per 339.4 and able to withstand normal transit; liquids must also follow 451.3(a) |
| Photographic mixtures — corrosive liquid solutions | USPS | restricted | domestic mail via air or surface transportation | Acceptable if qualifies as Limited Quantity air or surface; Packaging Instruction 8A must be followed; may be co-packed with non-hazardous dry chemicals |
| Poisonous drugs and medicines | USPS | restricted | domestic mail | Mailable only from manufacturers or dealers to licensed professionals (physicians, surgeons, dentists, pharmacists, etc.) per 18 U.S.C. 1716 |
| Poisons | USPS | restricted | domestic | Some poisons may be sent by air and ground transport, others only by ground |
| Pool shock / chlorine tabs | USPS | restricted | domestic US | Classified as oxidizer. Requires hazmat declaration. $50 noncompliance fee if undeclared, effective July 12, 2026. |
| Portable chargers / power banks | USPS | restricted | domestic US | Standalone lithium batteries require hazmat declaration at label creation. Must carry lithium battery mark (Class 9). $50 noncompliance fee if undeclared, effective July 12, 2026. |
| Potassium peroxide | USPS | prohibited | all mail | Nonmailable Division 5.1 oxidizing substance |
| powders - dry materials that could cause damage | USPS | restricted | all domestic mail | Powders must be packed in sift-proof containers or other containers that are sealed in durable sift-proof outer containers |
| prescription medications containing controlled substances | USPS | allowed | domestic mail - from authorized dispensers | Prescription medicines containing mailable narcotic drugs (controlled substances) may be mailed only by drug manufacturers or their registered agents, pharmacies, medical practitioners, or other authorized dispensers, as permitted by 21 CFR Section 1307.11 |
| Propane — Division 2.1 flammable gas | USPS | restricted | domestic mail via surface transportation only | Mailable via surface transportation as Limited Quantity material only; air transportation is prohibited |
| queen honeybees | USPS | restricted | domestic mail - air or surface transportation | May be shipped via air or surface transportation; each mailpiece shipped via air is limited to one queen and eight or fewer attendant honeybees; must be plainly marked 'Live Queen Bees' |
| Radioactive instruments and articles (UN2911) — clocks, electronic tubes | USPS | restricted | domestic mail via surface transportation | Mailable if activity does not exceed limits in Exhibit 347.22; classified as excepted package for simplified handling per 49 CFR 172.101; must follow Packaging Instruction 7A |
| Radioactive materials bearing Class 7 labels — international mail | USPS | prohibited | international mail | Radioactive materials bearing or required to bear a Class 7 Radioactive White-I, Yellow-II, or Yellow-III label are prohibited; eligible shipments may only go via First-Class Package International Service with Registered Mail |
| Radioactive materials bearing Class 7 labels or Fissile label — domestic surface | USPS | prohibited | domestic mail via surface transportation | Radioactive materials bearing or required to bear Radioactive White-I, Yellow-II, Yellow-III, or Fissile label are prohibited from domestic surface mail |
| Radioactive materials (Hazard Class 7) — domestic air | USPS | prohibited | domestic mail via air transportation | All radioactive materials are prohibited from domestic air mail |
| Regulated magnetized materials — international mail | USPS | prohibited | international mail | Regulated magnetized materials are prohibited from international mail; only non-regulated materials with field strength below 0.002 gauss at 7 feet may be mailed internationally |
| rifles and shotguns - unloaded, intrastate | USPS | allowed | domestic mail - intrastate shipments | Subject to state regulations; mailpiece must display Return Service Requested endorsement and be shipped using tracking and signature capture service |
| Safety Fuses (UN0105, Division 1.4S) | USPS | restricted | domestic surface transportation only | Mailable only with prior written approval from director, Product Classification; must be prepared per Packaging Instruction 1B; shipping paper required |
| Safety Matches | USPS | prohibited | international | Safety matches must be sent via ground transportation and cannot be mailed internationally. |
| Safety matches (book, card, or strike-on-box) | USPS | restricted | domestic mail via surface transportation only | Permitted only in domestic mail via surface transportation; must follow Packaging Instruction 4B; mailpieces marked 'Surface Only' or 'Surface Mail Only' |
| Sharps and regulated medical waste containing Category B infectious substance (UN3291) | USPS | restricted | domestic mail via USPS Ground Advantage only | Permitted via USPS Returns Service via USPS Ground Advantage only; vendor must obtain prior authorization; strict packaging, testing, labeling requirements apply |
| short-barreled rifles or shotguns - concealable | USPS | prohibited | all domestic mail | Short-barreled rifles or shotguns that can be concealed on the person are nonmailable |
| Shotgun hulls, empty casings, nonmetallic shotgun hulls, or casings without primers | USPS | allowed | all domestic mail | Not classified as explosives or hazardous materials under 49 CFR; mailable subject to applicable mailing rules |
| Small Arms Ammunition regulated as Class 1 explosive | USPS | prohibited | all mail | Ammunition regulated as Class 1 explosive fired from pistol, revolver, rifle, or shotgun; associated primers, blank cartridges, and propellant powder are prohibited |
| Small consumer-type lithium-ion batteries in equipment (up to 20 Wh per cell, 100 Wh per battery) | USPS | restricted | domestic mail via air and surface transportation | Mailable via air and surface; cells not to exceed 20 Wh, batteries not to exceed 100 Wh; up to 8 cells or 2 batteries per mailpiece; must display DOT-approved lithium battery mark |
| Small consumer-type lithium metal batteries in equipment (up to 1g per cell, 2g per battery) | USPS | restricted | domestic mail via air and surface transportation | Mailable via air and surface; cells not to exceed 1g lithium, batteries not to exceed 2g lithium; up to 8 cells or 2 batteries per mailpiece; must display DOT-approved lithium battery mark |
| small harmless cold-blooded animals (except snakes, turtles, turtle eggs) | USPS | allowed | domestic mail | Mailable only when they meet specific requirements including ability to reach destination in good condition, not requiring food or water (except fish), not creating sanitary problems or obnoxious odors; includes baby alligators, chameleons, frogs, lizards, newts, salamanders, tadpoles, goldfish, tropical fish, worms, leeches, snails, and nonpoisonous insects |
| smokeless tobacco | USPS | restricted | all domestic mail | Any finely cut, ground, powdered, or leaf tobacco intended to be placed in the oral or nasal cavity or otherwise consumed without combustion |
| snakes, turtles, and poisonous reptiles | USPS | prohibited | all domestic mail | All snakes, turtles, and poisonous reptiles are nonmailable |
| Sodium chlorite | USPS | prohibited | all mail | Nonmailable Division 5.1 oxidizing substance |
| Spray paint (aerosol) | USPS | restricted | domestic US | Classified as flammable aerosol. Requires hazmat declaration and rigid outer packaging. $50 noncompliance fee if undeclared, effective July 12, 2026. |
| Strike-Anywhere Matchessources differ | USPS | prohibited | domestic | Strike-anywhere matches may not be mailed domestically. |
| Strong magnets (rare-earth, magnetic phone mounts, certain speakers, magnetic toys) | USPS | restricted | domestic US | Classified as hazardous due to magnetic field strength. Requires hazmat declaration. $50 noncompliance fee if undeclared, effective July 12, 2026. |
| Sulfuric acid (UN2796) | USPS | restricted | domestic mail via air or surface transportation | Acceptable only in solutions of 25% or less acid that qualify as Limited Quantity air or surface; Packaging Instruction 8A must be followed |
| switchblade knife | USPS | restricted | all domestic mail | A switchblade knife features a blade that opens automatically by hand pressure applied to a button or other device on the handle, or through inertia, gravity, or both; mailable only to specific government and manufacturer recipients |
| switchblade knife - manufacturer or dealer to authorized recipients | USPS | allowed | domestic mail - from authorized manufacturers or dealers to authorized recipients | Authorized manufacturers or bona fide dealers may mail switchblade knives to government procurement officials or authorized recipients in connection with official procurement or resale |
| switchblade knife - to government procurement officials | USPS | allowed | domestic mail - to government supply or procurement officials only | Mailable only to designated government officers or employees ordering or procuring switchblade knives in connection with government activities, including federal civilian and armed forces, National Guard, Air National Guard, militia, and municipal government supply or procurement officers |
| Tear gas | USPS | prohibited | all mail | Nonmailable irritating material; exceptions may exist for those containing oleoresin capsicum |
| Tetranitromethane | USPS | prohibited | all mail | Nonmailable Division 5.1 oxidizing substance |
| Toxic gases (Division 2.3) | USPS | prohibited | all mail | All Division 2.3 toxic gases are prohibited from mailing |
| Toxic substances with LD50 oral toxicity greater than 5 mg/kg but no more than 50 mg/kg | USPS | restricted | domestic mail | Mailable only when sent between authorized parties (manufacturers, dealers, bona fide research labs, or government employees for official use); for domestic air a Shipper's Declaration for Dangerous Goods is required |
| Toy Propellant Devices (UN0454 or NA0323, Division 1.4S) | USPS | restricted | domestic mail via surface transportation only | Mailable via surface transportation with prior written permission from director, Product Classification; must meet strict requirements on size, design, and packaging; shipping paper required |
| Used, damaged, or defective electronic devices | USPS | prohibited | international mail and domestic air transportation | Prohibited from international mail and domestic air transportation; exceptions for new devices in original packaging or manufacturer-certified new/refurbished devices; surface transport must mark with 'Restricted Electronic Device' and 'Surface Transportation Only' |
| Used health care products (not suspected to contain Category A) | USPS | restricted | domestic mail via Priority Mail or Priority Mail Express only | Mailable with Priority Mail or Priority Mail Express when being returned to manufacturer or manufacturer's designee; must meet specific packaging requirements |
| Used healthcare products containing Category A infectious substance | USPS | prohibited | all mail | Used healthcare products containing a Category A infectious substance are nonmailable |
| warm-blooded animals (cats, dogs, guinea pigs, hamsters, mice, rabbits, rats, squirrels) | USPS | prohibited | all domestic mail | Warm-blooded animals, except for adult birds and specified day-old birds, are not mailable; nonmailable list includes cats or kittens, dogs or puppies, guinea pigs, hamsters, mice, rabbits, rats, squirrels and flying squirrels |
| Waxes and polishes (flammable or combustible liquid) | USPS | restricted | domestic mail via surface transportation | Mailable if qualify as Limited Quantity surface materials and meet conditions; Packaging Instruction 3A or 3B as applicable |
| Wireless earbuds | USPS | restricted | domestic US | Requires hazmat declaration at label creation (Service Type Code), DOT Class 9 hazard label (lithium battery mark), and rigid outer packaging. Cannot be shipped via air modes without proper declaration. $50 noncompliance fee if undeclared, effective July 12, 2026. |
| Zinc ammonium nitrate | USPS | prohibited | all mail | Nonmailable Division 5.1 oxidizing substance |
Where this came from
Every record above links the page it was taken from and quotes the sentence that states it. These are the 2 sources this dataset was assembled from.
- usps.comhttps://www.usps.com/ship/shipping-restrictions.htm
- postoffice.co.ukhttps://www.postoffice.co.uk/mail/what-can-i-send
Machine-readable
- data.jsonThe whole dataset — every record with its source URL and source quote.
- Open Knowledge Format bundleOne file per record, frontmatter plus the quoted span, exactly as it is held here.
- How this is made and checkedWhat "verified against source" does and does not mean.