# Milport Enterprises, Inc. — Hazardous Materials Safety Interpretation **Citation:** 21-0045 **Type / status:** guidance / guidance **Agency:** Pipeline and Hazardous Materials Safety Administration **Effective:** Not stated **Published:** 2021-06-22 21-0045 response to Milport Enterprises, Inc. concerning 172.101, 173.24a. ## Document text <<>> U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Avenue, SE Washington, DC 20590 June 22, 2021 Mr. Tom Grego Technical Director Milport Enterprises, Inc. 2829 South 5th Court Milwaukee, WI 53207 Reference No. 21-0045 Dear Mr. Grego: This is in response to your April 22, 2021, letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the packaging requirements for “UN2672, Ammonia solution, 8, PG III.” Specifically, you seek clarification on the applicability of special provision 336, which is listed in Column 7 of the § 172.101 Hazardous Materials Table (HMT) for this material. In your letter, you state that your company received a citation for transporting the above hazardous material in a packaging meeting the requirements of §§ 173.24(g) and 173.24a(b)(4), but not in a packaging described in special provision 336. It is your understanding that special provision 336 was added to the HMR in a final rule published on March 18, 2014 [79 FR 15033] under Docket No. PHMSA-2011-0158 (HM-233C), which adopted the terms of Special Permit (SP) DOT-SP 11836 as an alternative packaging method than what is required in §§ 173.24(g) and 173.24a(b)(4). You seek confirmation that it was not the Pipeline and Hazardous Materials Safety Administration’s (PHMSA) intent to require the operational controls in special provision 336 to apply to packagings meeting the requirements of §§ 173.24(g) and 173.24a(b)(4). Your understanding is correct. In the HM-233C final rule, PHMSA adopted DOT-SP 11836 as new special provision 336. As stated in the HM-233C final rule, “DOT-SP 11836 authorizes the transportation of specific ammonia solutions in specification UNIH1 drums, UN3H1 jerricans, and UN6HA1 composite packagings that do not meet the provisions in §§ 173.24(g) and 173.24a(b)(4). Specific operational controls are required in lieu of compliance with these two requirements.” <<>> Therefore, packagings for specific ammonia solutions such as “UN2672, Ammonia solution, 8, PG III” that meet the provisions of §§ 173.24(g) and 173.24a(b)(4) are not required to meet the operational controls of special provision 336. I hope this information is helpful. Please contact us if we can be of further assistance. Sincerely, T. Glenn Foster Chief, Regulatory Review and Reinvention Branch Standards and Rulemaking Division <<>> Edmonson 21-0045 From: INFOCNTR (PHMSA) To: Dodd, Alice (PHMSA) Subject: FW: Interpretation of Special Provision 336 in 172.102 Date: Friday, April 23, 2021 3:46:52 PM Attachments: PHMSA Interpretation request.pdf Hi Alice, Please see the attached interpretation request. Let me know if you need anything else from us. Regards, -Breanna From: Thomas Grego [mailto:Thomas.Grego@milport.com] Sent: Thursday, April 22, 2021 8:01 PM To: PHMSA HM InfoCenter Subject: Interpretation of Special Provision 336 in 172.102 CAUTION: This email originated from outside of the Department of Transportation (DOT). Do not click on links or open attachments unless you recognize the sender and know the content is safe. Please see attached request for a formal interpretation of Special Provision 336. ## Provenance - Official: Yes - Source: - Source ID: `phmsa` - SHA-256: `c1ac335b301a30a552765c25150af68e133da198f40ad214a50ccd2f719a53ea` - Retrieved: 2026-08-20T00:59:31.977Z - Exported: 2026-08-23T03:26:37.843Z - Document slug: `phmsa-interpretation-21-0045` ### Source metadata ```json { "materialSubtype": "interpretation", "interpretationArea": "hazardous_materials", "representation": "full_text_from_official_pdf", "companies": [ "Milport Enterprises, Inc." ], "individuals": [ "Tom Grego" ], "refIds": [ "21-0045" ], "catalogDates": [ "2021-06-22" ], "catalogParts": [ 172, 173 ], "catalogRowCount": 2, "sourceRecordUrls": [ "https://www.phmsa.dot.gov/node/72761" ], "linkedAttachmentUrls": [], "unavailableResponseUrls": [], "duplicateRepresentationUrls": [], "citedSections": [ "172.101", "173.24a", "173.24a(b)(4)", "173.24(g)", "172.102" ], "catalogPageUrls": [ "https://www.phmsa.dot.gov/regulations/title49/section/172101", "https://www.phmsa.dot.gov/regulations/title49/section/17324a" ], "pdfUrls": [ "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/75316/210045.pdf" ], "representations": [ { "viewUrl": "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/75316/210045.pdf", "detailUrl": null, "detailHtmlPath": null, "pdfUrl": "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/75316/210045.pdf", "pdfArtifactPath": "data/sources/phmsa-interpretations/21-0045-621461036d.pdf", "pdfArtifactSha256": "acb5d3b081c615477d23c02f7c7f7e6e7b86d767d086314d6359cde6a316e1bf", "extractedTextPath": "data/sources/phmsa-interpretations/21-0045-621461036d.v2.txt", "extractedTextSha256": "301562c6a314298fb317ec39921976f3921b1277fbd26630edcee13a9d0c4aa2", "pageCount": 3, "extractionVersion": 2 } ], "caveat": "Interpretations apply regulations to the facts presented and do not create independently enforceable requirements.", "jurisdiction": "US" } ```