{"operation":"document","citation":"25-0163","title":"Catawba Corps — Hazardous Materials Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"2026-06-25","effective_on":null,"summary":"25-0163 response to Catawba Corps concerning 173.453.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-25-0163.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-25-0163.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-25-0163","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/2026-06/25-0163.pdf","body":"<<<PAGE 1>>>\n\nU.S. Department\nof Transportation\nPipeline and Hazardous\nMaterials Safety\nAdministration\nJune 25, 2026\nJohn B. Woodbury\nPackaging Management Council Coordinator\nCatawba Corps\n3533 15th Street E\nLewiston, ID 83501\nReference No. 25-0163\nDear Mr. Woodbury:\nThis letter is in response to your December 15, 2025 email requesting clarification of the\nHazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to fissile materials.\nSpecifically, you ask whether a liquid payload can qualify for the fissile exceptions in\n§ 173.453(b).\nYes. In order to qualify for the fissile material exceptions in § 173.453(b), the packaging must\ncontain “15 grams or less of fissile material provided the package has at least 200 grams of solid\nnonfissile material for every gram of fissile material.” While the nonfissile material in this\ncalculation must be solid, § 173.453(b) does not require that the fissile material be solid.\nI hope this information is helpful. Please contact us if we can be of further assistance.\nSincerely,\n1200 New Jersey Avenue, SE\nWashington, DC 20590\nAlexander Wolcott\nActing Chief, Regulatory Review and Reinvention Branch\nStandards and Rulemaking Division\n\n<<<PAGE 2>>>\n\nJacobson, N.\n25-0163\nFrom: INFOCNTR (PHMSA)\nTo: Baker, Yul (PHMSA)\nCc: Hazmat Interps\nSubject: FW: LOI 24-0124 Clarification\nDate: Tuesday, December 16, 2025 11:49:32\nGood morning,\nMr. Woodbury requested and received letter of interpretation #24-0124 early this year. He had a\nfollow question to clarify the guidance in that letter. I reached out Mr. Noah Jacobson, received\nguidance, and relayed it to Mr. Woodbury.\nMr. Woodbury wanted the response in writing, so I am submitting this new LOI request on his behalf.\nPlease let me know if you need anything.\nBest,\nAminah\nFrom: John Woodbury <John.Woodbury@catawbacorps.com>\nSent: Monday, December 15, 2025 4:21 PM\nTo: INFOCNTR (PHMSA) <INFOCNTR.INFOCNTR@dot.gov>\nSubject: LOI 24-0124 Clarification\nCAUTION: This email originated from outside of the Department of Transportation (DOT). Do\nnot click on links or open attachments unless you recognize the sender and know the content\nis safe.\nYour response is greatly appreciated. However, the response to my letter does not fully\naddress my question. The most important part concerns whether 49 CFR 173.453(b) includes\nliquid as the payload.\n49 CFR 173.453(b) states:\nAn individual or bulk packaging containing 15 grams or less of fissile material provided the\npackage has at least 200 grams of solid nonfissile material for every gram of fissile material.\nLead, beryllium, graphite, and hydrogenous material enriched in deuterium may be present in\nthe package but must not be included in determining the required mass for solid nonfissile\nmaterial.\nYour response indicates that the packaging mass can be used to fulfill the solid nonfissile\nmaterial requirement. Please clarify if 49 CFR 173.453(b) can have a liquid payload.\n\n<<<PAGE 3>>>\n\nThanks,\nJohn B. “Woody” Woodbury\nPackaging Management Council Coordinator\n(509) 438-6342\nJohn.woodbury@catawbacorps.com","truncated":false,"body_characters":3068}