Policies, Procedures, and Forms Updates


DMM Revision: New Mailing Standards for Mailpieces Containing Liquids

Effective March 28, 2019, the Postal Service™ is revising Mailing Standards of the United States Postal Service, Domestic Mail Manual (DMM®), section 601.3.4, to clarify mailing standards for packaging and marking mailpieces containing nonhazardous liquids.

On July 9, 2018, the Postal Service published a Federal Register proposed rule (83 FR 31712-31713), titled “New Mailing Standards for Mailpieces Containing Liquids.” In this proposed rule, the Postal Service announced its intent to revise DMM 601.3.4 relating to mailpieces containing nonhazardous liquids, and to similarly revise Publication 52, Hazardous, Restricted, and Perishable Mail, to align with the wording and requirements in DMM 601.3.4.

Following feedback received on its proposed rule, on March 18, 2019, the Postal Service published a final rule (84 FR 9716-9719), also titled “New Mailing Standards for Mailpieces Containing Liquids.” In the final rule or planned revision, the Postal Service moved forward with the proposed clarification wording and incorporated additional changes that mailers suggested during the comment period for the proposed revision. Specifically, the Postal Service will remove ambiguity in the meaning of “breakable container” as defined in the rule, in addition to clarifying packaging requirements for those containers.

The Postal Service expects these revisions to improve compliance by reducing confusion about the definition and rule—consequently limiting the frequency of noncompliant mailers.

Also, for convenience and simplicity, in addition to including wording and rules in Publication 52 similar to those in revised section 601.3.4, the Postal Service will consolidate requirements for packaging liquids from Publication 52 into revised section 601.3.4, adding a reference to Publication 52, section 226, regarding requiring package orientation markings for mailing liquids and other spillable materials.

In its July 9, 2018, proposed rule, the Postal Service stated that mailpieces containing liquids are often not marked on the outer mailing container as required in DMM 601.3.4. In these cases, the Postal Service often finds that leaking mailpieces contain plastic primary receptacles. Mailers frequently related that they do not consider plastic primary receptacles to be breakable, and, therefore, do not cushion primary receptacles with absorbent material and include secondary containers as specified in DMM 601.3.4.

The proposed rule consisted of two components:

1. Clarification of existing language that specified packaging and markings for mailpieces containing liquids.

2. A proposal to extend the requirement to triple-package breakable primary containers with volumes of 4 ounces or less.

Current mailing standards require triple packaging only for breakable primary containers over 4 ounces.

The Postal Service received 20 responses to the July 9, 2018, published proposed rule, with some responders providing multiple comments. Some commenters supported the proposed revision, and some opposed it. Commenters included trade groups representing shippers of hazardous materials, individual mailers, mailer organizations, pharmaceutical mailers, technical and professional service providers, and Postal Service employees.

As a result of concerns that commenters voiced to the proposed rule, the Postal Service will not move forward at this time with its proposal to require triple-packaging of breakable primary containers with a volume of 4 ounces or less. The Postal Service will continue to monitor the frequency and impact of spills originating from these smaller containers, and determine at a future date revised mailing standards relating to smaller containers of liquids.

Although the Postal Service will not publish these revisions in the DMM until June 23, 2019, the standards are effective immediately.

Mailing Standards of the United States Postal Service, Domestic Mail Manual (DMM)

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600 Basic Standards For All Mailing Services

601 Mailability

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3.0 Packaging

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3.4 Liquids

[Revise 3.4 to read as follows:]

Mailers must mark the outer container of a mailpiece containing liquid to indicate the nature of the contents (i.e., liquid), and include orientation arrows in accordance with Publication 52, section 226. Mailers must package and mail liquids according to the following requirements:

a. Use screw-on caps (with a minimum of one and one-half turns), soldering, clips, or similar means to close primary containers containing liquids. Do not use containers with friction-top closures (push-down tops) except as provided in 3.4c. The use of locking rings or similar devices are encouraged when mailing containers with friction-top closures (push-down tops).

b. Liquids in steel pails and drums with positive closures, such as locking rings or recessed spouts under screw-cap closures, may be mailed without additional packaging.

c. Breakable containers including, but not limited to, those made of glass, plastic, porcelain, and earthenware, and metal containers with pull-tabs (pop-tops) or friction-top closures, having a capacity of more than 4 fluid ounces must be triple-packaged according to the following requirements:

1. Cushion the primary container(s) with absorbent material capable of absorbing all of the liquid in the container(s) in case of breakage;

2. Place the primary container inside another sealed, leakproof container (secondary container), such as a watertight can or plastic bag; and

3. Use a strong and securely sealed outer mailing container durable enough to protect the contents and withstand normal processing in Postal Service networks.

d. As an alternative to 3.4c, mailers may use containers certified under the International Safe Transit Association (ISTA) Test Procedure 3A. Mailers must, upon request, provide written test results verifying that sample mailpieces passed each test outlined in the standard and that no liquids were released.

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Although effective on March 28, 2019, the Postal Service will incorporate these revisions into the next edition of the online DMM, which is available via Postal Explorer® at pe.usps.com.