# The Hartford Steam Boiler Inspection and Insurance Co. — Hazardous Materials Safety Interpretation **Citation:** 24-0118 **Type / status:** guidance / guidance **Agency:** Pipeline and Hazardous Materials Safety Administration **Effective:** Not stated **Published:** 2025-04-21 24-0118 response to The Hartford Steam Boiler Inspection and Insurance Co. concerning 180.205, 180.212. ## Document text <<>> U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Avenue, SE Washington, DC 20590 April 21, 2025 Timothy J. Nuoffer Field Services Manager The Hartford Steam Boiler Inspection and Insurance Co. One State Street P.O. Box 5024 Hartford, CT 06102-5024 Reference No. 24-0118 Dear Mr. Nuoffer: This letter is in response to your November 27, 2024 letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to rethreading of DOT 3-series specification cylinders. Specifically, you ask about re-tapping (also known as rethreading) in accordance with §§ 180.205(f)(7) and 180.212, respectively. We have paraphrased and answered your questions as follows: Q1. Does letter of interpretation (LOI) Reference No. 09-0111 allow repair facilities with an approval in accordance with § 107.805 to rethread DOT 3-series specification cylinders? A1. PHMSA’s Office of Hazardous Materials Safety provides written clarifications of the HMR in the form of LOIs, in accordance with 49 CFR 105.20(a). These letters reflect the agency’s current application of the regulations to the specific facts presented by the person requesting the clarification. LOIs are not generally applicable, do not create legally-enforceable rights or obligations, and are provided to help the specific requestor understand how to comply with the regulations in their specific circumstances. Section 180.212(a) requires a repair facility to hold an approval issued under the provisions of § 107.805 to repair a DOT 3-series or a seamless United Nations (UN) pressure receptacle, which includes rethreading a DOT 3-series specification cylinder. Q2. Is the cylinder manufacturer—permitted to perform rethreading of DOT 3-series specification cylinders under the exception in § 180.212(b)(2)—required to be the original cylinder manufacturer? <<>> A2. No. The rethreading of a DOT 3-series specification cylinder is not required to be performed by the original manufacturer. However, please note the cylinder manufacturer performing rethreading must be a manufacturer of the specific cylinder type for which the rethreading is being performed. PHMSA recognizes that § 180.205(f)(7) states re- tapping of cylinder threads is not permitted, except by the original manufacturer, as provided in § 180.212. In an earlier rulemaking1, PHMSA revised the wording in § 180.212(b)(2) to clarify that the rethreading of cylinders may be performed by a manufacturer of the type of cylinder being rethreaded instead of limiting the work to the original manufacturer, who may no longer be in business. PHMSA may consider a similar revision to § 180.205(f)(7) in a future rulemaking. I hope this information is helpful. Please contact us if we can be of further assistance. Sincerely, Dirk Der Kinderen Chief, Standards Development Branch Standards and Rulemaking Division 1 “Hazardous Materials: Editorial Corrections and Clarifications (RRR)”, 70 FR 55678 (Oct. 1, 2007). <<>> 24-0118 Roundtree Jones, Jessie Jane (PHMSA) From: Cardez, Eugenio (PHMSA) Sent: Wednesday, November 27, 2024 1:17 PM To: Hazmat Interps Subject: FW: Request for Interpretation Regarding Rethreading and Interp 09-0111 Attachments: Rethread Interp09-0111_Interp11202024.pdf Follow Up Flag: Follow up Flag Status: Flagged Hey Alice and Jessie, please add to interp q. Thanks, Eugenio From: Cassidy, Duane (PHMSA) Sent: Wednesday, November 27, 2024 12:15 PM To: Cardez, Eugenio (PHMSA) Subject: FW: Request for Interpretation Regarding Rethreading and Interp 09-0111 Please take a look regarding a question to an interp received to approvals@dot.gov. Duane M. Cassidy Chief, Pressure Vessels Branch (PHH-25) Sciences and Engineering Division Office of Hazardous Materials Safety US Department of Transportation Pipeline and Hazardous Materials Safety Administration E21-301, 1200 New Jersey Ave SE, Washington, DC 20590 Office/Mobile: 202.596.0583 PHMSA Home | LinkedIn | Twitter | HAZMAT | OPS From: Nuoffer Timothy - Hartford-Remote-HSB Sent: Wednesday, November 27, 2024 12:08 PM To: INFOCNTR (PHMSA) Cc: Cassidy, Duane (PHMSA) Subject: Request for Interpretation Regarding Rethreading and Interp 09-0111 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 the attached request for interpretation regarding rethreading of DOT 3-series cylinders and DOT interpretation 09-0111. 1 <<>> Regards, Timothy Nuoffer Field Services Manager- Transportation Services The Hartford Steam Boiler Inspection and Insurance Company One State Street P.O. Box 5024 Hartford, CT 06102-5024 Telephone: +1 (618) 444-7628 Timothy_Nuoffer@hsb.com hsb.com IMPORTANT NOTICE: This email (including any attachments) contains confidential and proprietary information that is intended only for the individual or entity designated above. If you are not the intended recipient, please be aware that any use, review, distribution, reproduction, copying, or action taken in reliance upon this email is strictly prohibited. If you received this email in error, please notify the sender immediately, and permanently delete and destroy this email and any hard and electronic copies thereof. Although we have taken reasonable precautions to reduce the risk of transmitting software viruses, it is the responsibility of the recipient to ensure that this email is virus-free. The Hartford Steam Boiler Inspection and Insurance Company (including its subsidiaries and affiliates) disclaims any and all liability for any loss or damage caused by this email whether due to viruses, interference, interception, data corruption, unapproved access, misrepresentation, or otherwise. IMPORTANT NOTICE: This email (including any attachments) contains confidential and proprietary information that is intended only for the individual or entity designated above. If you are not the intended recipient, please be aware that any use, review, distribution, reproduction, copying, or action taken in reliance upon this email is strictly prohibited. If you received this email in error, please notify the sender immediately, and permanently delete and destroy this email and any hard and electronic copies thereof. Although we have taken reasonable precautions to reduce the risk of transmitting software viruses, it is the responsibility of the recipient to ensure that this email is virus-free. The Hartford Steam Boiler Inspection and Insurance Company (including its subsidiaries and affiliates) disclaims any and all liability for any loss or damage caused by this email whether due to viruses, interference, interception, data corruption, unapproved access, misrepresentation, or otherwise. 2 <<>> Standards and Rulemaking Division Pipeline and Hazardous Materials Safety Administration Attn: PHH-10 US Department of Transportation East Building 1200 New Jersey Avenue, SE Washington, DC 20590-0001 To whom it may concern: 180.205(f)(7) Rethreading and Interpretation 09-0111 I have the following inquiry concerning the validity of US DOT interpretation 09-0111 and paragraphs 49CFR180.205(f)(7) and 49CFR180.212(b)(2) regarding who can rethread DOT 3-series cylinders. Background: Paragraph 180.205(f)(7) allows the re-tapping of threads to only be performed by the original manufacturer in accordance with 180.212. It appears this requirement was added in the 10/1/2021 edition of the HMR. Paragraph 49CFR180.212(a)(1) allows repairs of DOT-3 series cylinders to be performed by a repair facility that holds an approval issued under 49CFR107.805 or the repairs are performed under an approval issued under subpart H of part 107 or by a facility registered by Transport Canada. In addition, paragraph 49CFR180.212(b)(2) allows for the cylinder manufacturer to rethread cylinders without prior approval. The words in the 180.212 paragraphs appear to be the same words at the time of interpretation 09-0111 was issued. Interpretation 09-0111 date of issue was 12/03/2012. Answer number 2 of the interpretation allows repair facilities to rethread DOT 3-series cylinders. Question #1: Is interpretation 09-0111, which allows repair facilities that have approval per 49CFR107.805 to rethread DOT-3 series cylinders? Answer #1: Yes. Paragraph 49CFR180.212(a)(1) provides an exception to the 49CFR180.205(f)(7) requirement of re-tapping of threads can only be performed by the original cylinder manufacturer. DOT-3 series rethreading may be performed by a repair facility that has approval per 49CFR107.805. 27 November 2024 Timothy J. Nuoffer Field Services Manager Codes & Standards Tel.: (618) 444-7628 Timothy_Nuoffer@hsb.com The Hartford Steam Boiler Inspection and Insurance Co. One State Street P.O. Box 5024 Hartford, CT 06102-5024 www.munichre.com/HSB <<>> Page 2 27 November 2024 Question #2: Paragraph 49CFR180.212(b)(2) allows the rethreading of DOT-3 series cylinders to be performed without prior approval by a manufacturer of DOT-3 series cylinders. Must this manufacturer be the original cylinder manufacturer? Timothy J. Nuoffer Field Services Manager Codes & Standards Tel.: (618) 444-7628 Timothy_Nuoffer@hsb.com Answer #2: No A reply as soon as possible would be greatly appreciated. Should you have additional questions or need to discuss, please call 618-444-7628. Sincerely, The Hartford Steam Boiler Inspection and Insurance Co. ## Provenance - Official: Yes - Source: - Source ID: `phmsa` - SHA-256: `27f7e2b8d96301a63bd217985aab7df52e6a25d227813ce18bf7b7c1c836d593` - Retrieved: 2026-08-20T00:59:31.977Z - Exported: 2026-08-23T09:44:54.731Z - Document slug: `phmsa-interpretation-24-0118` ### Source metadata ```json { "materialSubtype": "interpretation", "interpretationArea": "hazardous_materials", "representation": "full_text_from_official_pdf", "companies": [ "The Hartford Steam Boiler Inspection and Insurance Co." ], "individuals": [ "Timothy J. 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