# Silverback Consulting Group LLC — Hazardous Materials Safety Interpretation **Citation:** 20-0040 **Type / status:** guidance / guidance **Agency:** Pipeline and Hazardous Materials Safety Administration **Effective:** Not stated **Published:** 2021-03-23 20-0040 response to Silverback Consulting Group LLC concerning 173.315. ## Document text <<>> U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Avenue, SE Washington, DC 20590 March 23, 2021 Mr. Michael Di Giorgio Silverback Consulting Group LLC Propane University 41 Woodside Avenue Hasbrouck Heights, NJ 07604 Reference No. 20-0040 Dear Mr. Di Giorgio: This letter is in response to your May 4, 2020, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the odorization of liquefied petroleum gas in cargo tanks and portable tanks, as required in 49 CFR 173.315(b)(1) and (2). Specifically, you ask several questions concerning the odorization of propane gas. We have paraphrased and answered your questions as provided below: Q1. You ask who would be responsible for ensuring that the amount of odorant (ethyl mercaptan), whether injected manually or automatically into a cargo tank or portable tank of propane, is sufficient as registered by the ethyl mercaptan injection meter. A1. Section 173.315(b)(2) states that for cargo tanks or portable tanks being transported from a refinery, gas plant, or pipeline terminal, the offeror must ensure that enough odorant will remain in the cargo tank or portable tank during the course of transportation and must have procedures to ensure that quantitative testing methods are used to measure the amount of odorant in the liquefied petroleum gas. This requirement would not apply to a secondary or retail shipper. Q2 You ask whether a company should request the calibration records for an odorant meter. A2. There is no requirement in the HMR that would prevent a person from requesting a copy of a calibration record of an odorant meter. However, there is also no requirement in the HMR that compels an offeror to supply such records. <<>> Q3. You ask whether a gas company that offers propane from its plant storage tanks for delivery to the end-user is responsible for performing a quantitative test to verify sufficient odorant is in the propane before it leaves the plant. A3. The answer is no. See Answer A1. Q4. You ask whether the odorant injected at the refinery is intended to last for one leg of transportation (from the refinery to the owner’s storage tank) or for the entire transportation of the propane (from the refinery to the owner’s storage tank to the end- user). A4. Section 173.315(b)(2) is limited to cargo tanks or portable tanks being transplanted from a refinery, gas plant, or pipeline terminal and states that the offeror must ensure that enough odorant will remain in the cargo tank or portable tank during transportation. For purposes of the HMR, transportation begins when a carrier takes physical possession of a hazardous material for the purposes of transporting it and continues until the hazardous material is delivered to the destination indicated on a shipping paper, package marking, or other medium. 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 20-0040 From: Ciccarone, Michael (PHMSA) To: Hazmat Interps Subject: FW: REQUEST FOR INTERPRETATION Date: Wednesday, May 6, 2020 8:59:41 AM Alice/Ikeya, Please log as a request for interp. Thanks, Mike From: DerKinderen, Dirk (PHMSA) Sent: Wednesday, May 6, 2020 8:47 AM To: Ciccarone, Michael (PHMSA) Subject: RE: REQUEST FOR INTERPRETATION Thanks Mike, If you haven’t already done so, have the HMIC forward to Alice/Ikeya for submittal and assignment. Thanks, Dirk Der Kinderen Chief, Standards Development Branch PHMSA 202-366-4460 From: Raynor, T'Mia (PHMSA) Sent: Monday, May 4, 2020 10:59 AM To: DerKinderen, Dirk (PHMSA) Subject: FW: REQUEST FOR INTERPRETATION Hi Dirk, Hope all is well. I received the below email in the webmaster inbox. Would you be able to assist or is there someone I can send these types of emails to? Thanks, T'Mia Raynor Webmaster PHMSA Office of the CIO (PHF-30) Desk: (202) 366-9818 | Mobile: (202) 580-9447 From: Silverback Consulting Propane University [mailto:hazmat1075@silverbackconsultingllc.com] <<>> Sent: Monday, May 4, 2020 8:47 AM To: PHMSA Webmaster Cc: Silverback Consulting Propane University Subject: REQUEST FOR INTERPRETATION To whom it may concern, Please help in our understanding of 173.315 (b)(1) and (2) as it relates to the quantitative testing for odorant in propane. It is my understanding that the regulation applies to the shipper/offeror and we interpret this to be the refinery (initial shipper). According to the regulation, the initial shipper needs to conduct the quantitative testing to ensure that the adequate amount of odorant (Ethyl Mercaptan) was injected into the cargo tank with the propane. This leads me to a few questions: 1. Whether the odorant is injected manually or automatically who is responsible to ensure the proper amount that was registered by the Ethyl Mercaptan injection meter was sufficient; the initial shipper/refinery or the secondary shipper (being the owner of the product) loading their own cargo tanks to fill end user tanks? Or both? In addition, should companies be requesting calibration records for the odorant meter? 2. Does the gas company that becomes the shipper when the propane leaves the plant (from their storage tanks) to be delivered to the end-user have the responsibility to perform a quantitative test to verify sufficient odorant is still in the propane? 3. Is the odorant injected at the refinery intended to last just for one leg of transportation (the refinery to the owner storage tank) or for the entire transportation of the propane from the refinery to owner storage to the end- user? The bottom line is that we all want to be safe and ensure that the odorant is included and effective for transportation to the end-user. We just need clarification on who needs to conduct the quantitative testing and what documentation should be obtained and maintained. Thank you for your help and support. Mike Di Giorgio Silverback Consulting Group LLC Propane University Your Transportation and Safety Leader <<>> Michael DiGiorgio Propane University Silverback Consulting Group 41 Woodside Avenue Hasbrouck Heights NJ 07604 Cell Phone 914 645 9631 Silverback Consulting Propane University hazmat1075@silverbackconsultingllc.com http://www.silverbackconsultingllc.com/ https://www.propaneuniversity.net/ TRAVEL SAFE E-Mail Circulation and or Sharing This E-mail This email is intended solely for the use of the individual to whom it is addressed and may contain information that is privileged, confidential or otherwise exempt from disclosure under applicable law. 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All items of information, documents (including electronically stored documents like email), and materials pertaining to the referenced subject are private and considered confidential. ## Provenance - Official: Yes - Source: - Source ID: `phmsa` - SHA-256: `6cc15e2964894d506141ad773520c21e2282b231645740105cc8d9ad2330ca3f` - Retrieved: 2026-08-20T00:59:31.977Z - Exported: 2026-08-22T14:58:08.760Z - Document slug: `phmsa-interpretation-20-0040` ### Source metadata ```json { "materialSubtype": "interpretation", "interpretationArea": "hazardous_materials", "representation": "full_text_from_official_pdf", "companies": [ "Silverback Consulting Group LLC" ], "individuals": [ "Michael Di Giorgio" ], "refIds": [ "20-0040" ], "catalogDates": [ "2021-03-23" ], "catalogParts": [ 173 ], "catalogRowCount": 1, "sourceRecordUrls": [ "https://www.phmsa.dot.gov/node/72551" ], "linkedAttachmentUrls": [], "unavailableResponseUrls": [], "duplicateRepresentationUrls": [], "citedSections": [ "173.315", "173.315(b)(1)" ], "catalogPageUrls": [ "https://www.phmsa.dot.gov/regulations/title49/section/173315" ], "pdfUrls": [ "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/74811/200040.pdf" ], "representations": [ { "viewUrl": "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/74811/200040.pdf", "detailUrl": null, "detailHtmlPath": null, "pdfUrl": "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/74811/200040.pdf", "pdfArtifactPath": "data/sources/phmsa-interpretations/20-0040-2159b99b02.pdf", "pdfArtifactSha256": "e9b2606c7c89ec0bcd21983a8f054965284daff2afa0646d2a2b36f425326acc", "extractedTextPath": "data/sources/phmsa-interpretations/20-0040-2159b99b02.v2.txt", "extractedTextSha256": "a83dea241d7147f5d17f72d1e87bfa21e2e24cd2f81f611eebfa731c3a323d31", "pageCount": 5, "extractionVersion": 2 } ], "caveat": "Interpretations apply regulations to the facts presented and do not create independently enforceable requirements.", "jurisdiction": "US" } ```