The Compliance Center (ICC)

PHMSA Proposes Changes to Air Packaging in HM-231A


The Pipelines and Hazardous Materials Safety Administration (PHMSA) has released a proposed rulemaking to the Hazardous Materials Regulations (HMR) designed to reduce the number of spills of liquid hazardous materials during air transportation. This Notice of Proposed Rulemaking (NPRM), HM-231A, responds to a number of studies on packaging failures by introducing new design requirements, as well as new testing procedures for proving that packagings can survive pressure changes in air transport.

 Recent studies of spills during air transport have shown packaging failure to be a common problem. For example, one study concluded that out of 1,583 air incidents studied, a failure of the inner packagings inside outer packagings (a typical “combination” package design) contributed to 333 incidents of spillage. Further studies have found that here has been little improvement in packaging performance over the past decade. Often, the failures are due to closures (caps, bungs, etc.) that loosen during air transport.

 PHSMA declares in the NPRM that “air transportation of hazardous materials requires clear standards, exceptional diligence, and attention to detail.” Steps proposed to remedy typical problems include:


  • Adoption of revised packaging instructions from the International Civil Aviation Organization (ICAO). This involves requirements for leakproof liners inside combination packaging, and secondary means of positive closure, such as taping or wiring.

  • Establishing an enhanced pressure differential capability standard. Currently, the HMR does not have very precise standards for how to verify that a receptacle for liquids can withstand an appropriate pressure differential. HM-231A will add an appendix to Part 173 referencing appropriate pressure test protocols from the American Society for Testing and Materials (ASTM), as well as a new standard for pressure-testing flexible containers such as plastic bags.


A full text of this Notice of Proposed Rulemaking may be found at


Comments must be received by July 13, 2010. Submissions identified by docket number PHMSA-07-29364 (HM-231A) may be sent to PHMS by the Federal eRulemaking Portal at, by fax to 1-202-493-2251, or by mail to:


            Docket Operations,

U.S. Department of Transportation,

            West Building, Ground Floor, Room W12-140, Routing Symbol M-30,

            1200 New Jersey Avenue, SE,

            Washington, DC 20590


If you have further questions on this NPRM, please feel free to contact us here at ICC The Compliance Center for more information.

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