Per an Industry Alert from the USPS® on March 18, 2019:
The Postal Service published a notice of proposed rulemaking on July 9, 2018, (83 FR 31712-31713) requesting public feedback on potential changes to DMM 601.3.4.
The July 9, 2018 proposed rule consisted of two components. The first component was the clarification of existing language that specified packaging and markings for mailpieces containing liquids. The second component was a proposal to extend the requirement to triple-package breakable primary containers with a volume of four (4) ounces or less. Current mailing standards require triple packaging only for breakable primary containers over 4 ounces.
The Postal Service will move forward with the proposed clarification language and incorporate some additional changes that were proposed by mailers during the comment period.
With regard to extending the requirement to triple-package breakable primary containers with a volume of 4 ounces or less, the Postal Service will not move forward with this proposal at this time. The Postal Service will continue to monitor the frequency and impact of spills originating for these smaller containers, and make a determination at a future date regarding mailing standards revisions relating to smaller containers of liquids.
For further information, contact Mary Collins at 202-268-55551 or Wm. Kevin Gunther at 202-268-7208.