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343 Flammable and Combustible Liquids
(Hazard Class 3)

343.1 Definition

The terms used in the standards that apply to Hazard Class 3 are defined as follows:

  1. Flammable Liquid means a liquid that has a flashpoint of not more than 141° F (60.5° C), or any material in a liquid phase that has a flashpoint at or above 100° F (38° C).
  2. Combustible Liquid means any liquid that does not meet the definition of any other hazard class and has a flashpoint above 141° F (60.5° C) and below 200° F (93° C). A flammable liquid with a flashpoint at or above 100° F (38° C) that does not meet the definition of any other hazard class may be reclassified as a combustible liquid per 49 CFR 173.120(b).
  3. Note: A liquid with a flashpoint above 200° F (93° C) is not regulated as a hazardous material and may be mailed subject to the general packaging requirements in DMM 601.1-7, provided it possesses no characteristics of another hazard class.

343.2 Mailability and Packaging

343.21 Requirements for Flammable Liquids

The following conditions apply:

  1. International Mail. Flammable liquid is prohibited.
  2. Domestic Mail via Air Transportation. Flammable liquid is prohibited.
  3. Domestic Mail via Surface Transportation. Flammable liquid with a flashpoint of 20° F (–7° C) or below is prohibited. Other flammable liquid is permitted if the material can qualify as an ORM–D material and meet the criteria in Exhibit 343.21. A mailable flammable liquid must be prepared according to Packaging Instruction 3A in Appendix C, as applicable.

Exhibit 343.21 

Flammable Liquids

 

Flashpoint

Mailability

20° F (–7° C) or below

Not acceptable for mailing.

Above 20° F (–7° C)
but not more than 73° F (23° C)

Acceptable (with restrictions) for domestic mail via surface transportation only. Follow requirements for Packaging Instruction 3A in Appendix C, as applicable.

Above 73° F (23° C)
but less than 100° F (38° C)

Acceptable (with restrictions) for domestic mail via surface transportation only. Follow requirements for Packaging Instruction 3A in Appendix C, as applicable.

100° F (38° C) and up
to 141° F (60.5° C)

Acceptable (with restrictions) for domestic mail via surface transportation only. Follow requirements for Packaging Instruction 3A or 3B in Appendix C, as applicable.

Note: If the flashpoint is between 100° F (38° C)
and 141° F (60.5° C), the liquid may be eligible to
be reclassed as a combustible liquid.

Over 141° F (60.5° C)

See combustible liquids in 343.22. Follow requirements for Packaging Instruction 3A in
Appendix C.

343.22 Requirements for Combustible Liquids

The following conditions apply:

  1. International Mail. Combustible liquid is prohibited.
  2. Domestic Mail via Air Transportation. Combustible liquid is permitted if the material can qualify as a consumer commodity material and meet the criteria in Exhibit 343.22. Packaging Instruction 3B in Appendix C must be followed, as applicable.
  3. Domestic Mail via Surface Transportation. Combustible liquid is permitted if the material can qualify as a consumer commodity material (for air or surface), or ORM-D (for surface only), and meet the criteria in Exhibit 343.22. Packaging Instruction 3B in Appendix C must be followed, as applicable.

Exhibit 343.22 

Combustible Liquids

 

Flashpoint

Mailability

Below 100° F (38° C)

Not a combustible liquid. See flammable liquids in 343.21.

100° F (38° C) but not more than 141° F (60.5° C)

A flammable liquid that may be eligible to be reclassified as a combustible liquid under
49 CFR 173.120(b). See 343.1. Acceptable (with restrictions) in domestic mail via surface transportation only. Follow requirements for Packaging Instruction 3B in Appendix C, as applicable.

Above 141° F (60.5° C)
but not more than
200° F (93° C)

Acceptable (with restrictions) for domestic mail via air transportation or surface transportation. Follow requirements for Packaging Instruction 3B in Appendix C, as applicable.

Above 200°F (93°C)

The material is not regulated as a hazardous material. Such nonregulated materials must be properly and securely packaged to prevent leakage under the general packaging requirements in DMM 601.2.0.

343.23 Nonmailable Flammable and Combustible Liquids

When flammable liquids and combustible liquids that are nonmailable under 343.21 or 343.22 are found in the mailstream, the procedures in POM 139.117 must be followed if the materials present an immediate threat to persons or property.

The following materials are nonmailable:

  1. All flammable liquids having a flashpoint of 20° F (–7° C) or below are prohibited from mailing.
  2. Gasoline (UN1203) is a flammable liquid that normally has a flashpoint of –50° F. Gasoline is nonmailable under any circumstances.
343.24 Mailable Flammable and Combustible Liquids

The following are mailable:

  1. Paint or a related item (UN1263) classified as a flammable or combustible liquid is generally acceptable for mailing 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 stated in 343.21 or 343.22, as applicable. Also see 343.26. Mailpieces must be prepared following Packaging Instruction 3A or 3B in Appendix C, as applicable.
  2. Latex Paint or a similar water–based paint product that is not flammable or combustible is not regulated as a hazardous material, and therefore is not restricted. Also see 343.26. Mailpieces must be properly packaged under DMM 601.1-7.
  3. Canned Heat (Sterno) is a flammable liquid that normally has a flashpoint from 40° F (4° C) to 80° F (27° C). It is permitted if 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 stated in 343.21. Mailpieces must be prepared following Packaging Instruction 3A in Appendix C.
  4. Cigarette Lighter Fluid is a flammable liquid that normally has a flashpoint between 20° F (–7° C) and 55° F (13° C). It is permitted only in domestic mail via surface transportation provided the fluid can qualify as a consumer commodity material or ORM-D, and is sent within the quantity limitations and packaging requirements stated in 343.21. Mailpieces must be prepared following Packaging Instruction 3A in Appendix C.
  5. Diesel Fuel (NA1993) is a combustible liquid that normally has a flashpoint between 110° F (43° C) and 190° F (88° C). It is acceptable for mailing provided the fluid can qualify as a consumer commodity material or ORM-D (for surface only), and the liquid is sent within the conditions in 343.22. Mailpieces must be prepared following Packaging Instruction 3B in Appendix C.
  6. Fuel Oil (NA1993) is a flammable liquid that normally has a flashpoint below 100° F (38° C). The specific flashpoint must be accurately identified by the mailer before a mailability determination can be made. Fuel oil is acceptable if the material can qualify as a consumer commodity material or ORM-D, and is sent within the quantity limitations and packaging requirements stated in 343.21 or 343.22, as applicable. Mailpieces must be prepared following Packaging Instruction 3A in Appendix C.
  7. Adhesives and Cements (UN1133) that are classified as flammable or combustible liquids are mailable only if the material can qualify as a consumer commodity material or ORM-D (for surface only), and the applicable conditions in 343.21 or 343.22 are met. Mailpieces must be prepared following Packaging Instruction 3A or 3B in Appendix C, as applicable.
  8. Note: Some adhesives and cements are extremely toxic and may be classified as Division 6.1 toxic substances. Division 6.1 materials are mailable only as permitted in 346.21.

  9. Cleaning Agents and Solvents that are classified as flammable liquids are mailable only if the material can qualify as a consumer commodity material or ORM-D (for surface only), and the applicable conditions in 343.21 can be met. Mailpieces must be prepared following Packaging Instruction 3A in Appendix C.
  10. Note: Some cleaning agents and solvents are extremely toxic or corrosive and may be classified as either a Division 6.1 toxic substance or a Class 8 corrosive. Division 6.1 toxic materials and Class 8 corrosives are permitted only within the conditions of 346.21 and 348.2 respectively.

  11. Model Fuel (for glow–plug engines) is a flammable liquid that has a flashpoint ranging from 65° F to 75° F. It is acceptable if the material can qualify as a consumer commodity material or ORM-D (for surface only), is sent within the quantity limitations, and meets the packaging requirements stated in 343.21. Mailpieces must be prepared following Packaging Instruction 3A in Appendix C.
  12. Waxes and Polishes have a wide range of flashpoints. The flashpoint and toxicity must be accurately identified by the mailer before mailability can be determined. Any waxes or polishes that are flammable or combustible liquids are permitted to be mailed, provided the material can qualify as a consumer commodity material or ORM-D (for surface only) and the applicable conditions in 343.21 and 343.22 are met. Mailpieces must be prepared following Packaging Instruction 3A or 3B in Appendix C, as applicable.
343.25 Cigarette Lighters

A cigarette lighter equipped with an ignition element and containing fuel is classified as a Class 3 flammable liquid. A cigarette lighter containing a flammable gas is classed as a Division 2.1 flammable gas. A cigarette lighter that contains either flammable liquid or flammable gas is permitted only in the domestic mail via surface transportation with prior written approval and within these conditions:

  1. The design of the lighter and its packaging are approved by the DOT Associate Administrator for Hazardous Materials Safety, per 49 CFR 173.21(i) and 173.308, and a DOT Approval Number (LAA****) is issued.
  2. The prospective mailer of the lighter submits to the PCSC manager a written request for authorization to mail the lighter, accompanied by a legible photocopy of the official DOT notice conveying the approval described in 343.25a, along with a specimen of the actual lighter, the packaging materials in which each lighter is to be mailed, and the number of mailpieces and mailing location; the mailer receives from the PCSC manager a letter approving the requested authorization for mailing.
  3. The packaging must be designed to protect the lighter’s sparking mechanism from accidental ignition caused by friction or external pressure during transport. Packaging Instruction 3C in Appendix C must be followed.
  4. When presented for mailing, the address side of the mailpiece must prominently display the proper shipping name “Lighter(s)” or “Lighter(s) for Cigarette” followed by the DOT Approval Number (LAA****) and the marking “Surface Only” or “Surface Mail Only,” all preparation and packaging requirements in the PCSC manager’s approval letter must be met. A legible photocopy of the PCSC manager’s approval must accompany the mailing at the time of deposit.
  5. A shipper’s declaration for dangerous goods is not required.
343.26 Paints, Paint–Related Materials, and Inks

The following definitions apply:

  1. Paint (UN1263) is the proper shipping name and description for paint, lacquer, enamel, stain, shellac, varnish, liquid aluminum, liquid bronze, liquid gold, liquid wood filler, and liquid lacquer base. Paintrelated material (UN1263) is the proper shipping name and description for a paint–thinning, paint–drying, paint–reducing, or paint–removing compound. See 343.24a and 343.24b for mailability.
  2. Inks are defined as colored liquids used for writing, drawing, etc., and liquids and pastes used in printing. Printing inks usually are mixtures of finely divided pigments, such as carbon black suspended in a drying oil. Inks having hazardous characteristics are generally classified as combustible or flammable liquids and are mailable, provided they can qualify as a consumer commodity material or ORM-D (for surface only), and meet the applicable requirements in 343.21 or 343.22. Mailpieces must be prepared using Packaging Instruction 3A or 3B in Appendix C, as applicable. In addition, the following conditions apply:
    1. Regardless of the size or type of container, the primary receptacle(s) containing inks must be cushioned with sufficient absorbent material to take up all liquid contents in case of leakage.
    2. The primary receptacle(s) and the absorbent cushioning material must be packed within a sealed, leakproof outer packaging.
    3. Inks that are flammable or combustible liquids must meet the quantity restrictions, packaging requirements, and air or surface transportation conditions that apply under 343.2.

    Note: Inks that do not possess any hazardous characteristics are not regulated as hazardous materials and are mailable if properly prepared under the requirements for packaging liquids in DMM 601.1-7.

343.27 DOT Special Permit Authorization (SP 9275)

On April 17, 2014, the Department of Transportation, Pipeline and Hazardous Materials Safety Administration division removed, via Federal Register final rule (March 18, 2014 79 FR 15033-15046), the requirement to apply for Special Permit 9275 (DOT-SP 9275) when shipping products containing ethyl alcohol.

Manufacturers and distributors currently holding approved permits in accordance with DOT Special Permit 9275 (DOT-SP 9275), and current authorization from the USPS manager, Product Classification, may continue to mail under these approvals until further notice. This allows the mailer to use Priority Mail, First-Class Mail, First-Class Package Service, or Parcel Select service for shipping in compliance with all DOT regulations in DOT-SP 9275 and the following mailing requirements:

  1. Once approved, the mailer must present a copy of its approval letter from the manager, Product Classification (to be kept on file at the office of mailing) at the time of its first mailing at any given Postal Service facility. The Postal Service has the right to refuse mailings not supported by a DOT authorization letter.
  2. The mailer will enter parcels using Priority Mail, First-Class Mail, First-Class Package Service, or Parcel Select service via a Postal Service authorized manifest mailing system (MMS) (see DMM 705.2.0).
  3. The mailer must label each parcel on the address side with “USPS Approved DOT-SP 9275” using at least 14-point type.
  4. The mailer must tender only parcels weighing 10 pounds or less. Each inner package (receptacle) may not exceed 16 ounces of flammable liquid or 1 pound of solids containing flammable liquid.
  5. The mailer must ensure that the addressee of each parcel is notified that the addressee is not authorized to remail the contents of the parcel via the Postal Service under DOT-SP 9275. The mailer must include the following notice:
  6. Flammable liquids contained in these packages may be mailed only by consumers (the addressee) via surface transportation in accordance with USPS Publication 52, section 343. Full responsibility rests with the mailer to comply with all postal and nonpostal statutes and regulations regarding mail. Information regarding postal statutes, regulations, and mailing requirements is available from your local Postmaster or district manager, Business Mail Entry, and at the Postal Service’s mailing standards website at pe.usps.com.

  7. The mailer must comply with the warning and labeling requirements set forth in 21 CFR 700, 740.1, and 701.3 when mailing each parcel.

343.3 Marking and Documentation

Parcels containing mailable flammable or combustible liquids must be marked as follows:

  1. For air transportation, parcels containing mailable Class 3 materials must bear the DOT square-on-point marking. The top and bottom portions of the square-on-point and the border forming the square-on-point must be black, and the center must be white or of a suitable contrasting background. The symbol “Y” must be black, located in the center of the square-on-point, and clearly visible. Mailpieces must also be marked with the proper shipping name “Consumer Commodity” and identification number “ID8000.” Each mailpiece must also bear an approved DOT Class 9 hazardous material warning label (see
    Exhibit 325.2b). A properly completed shipper’s declaration for dangerous goods prepared in triplicate must be affixed to the outside of the mailpiece.
  2. For surface transportation, parcels containing mailable Class 3 materials must be plainly and durably marked on the address side with “Surface Only” or “Surface Mail Only” and “ORM-D,” immediately following or below the proper shipping name (e.g., Consumer Commodity). Optionally, mailpieces may be marked with an approved DOT limited quantity square-on-point marking (see Exhibit 325.2a). The top and bottom portions of the square-on-point and the border forming the square-on-point must be black, and the center must be white or of a suitable contrasting background. Surface shipments containing qualifying ORM-D material bearing the square-on-point limited quantity marking are not required to be marked with the shipping name and identification number. A shipper’s declaration for dangerous goods is not required for mailable Class 3 materials sent via surface transportation.
  3. Markings must be durable, legible, and readily visible, and must be applied on at least one side or one end of the outer packaging. The border forming the square-on-point must be at least 2 mm in width, and the minimum dimension of each side must be 100 mm, unless the package size requires a reduced size marking of no less than 50 mm on each side.
  4. Cigarette lighters must be marked as specified in 343.25.
  5. Flammable liquids mailed under DOT-SP 9275 must be marked as specified in 343.27.