Letters of Interpretation

PHMSA has published several Frequently Asked Questions (FAQs) documents on programmatic topics. Please review these documents here at: https://www.phmsa.dot.gov/about-phmsa/phmsa-faqs.

Additionally, Office of Hazardous Materials Safety has published Hazardous Materials FAQs based on letters of interpretation on the following topics:

Office of Hazardous Materials Safety: For questions about transporting hazardous materials, needing clarifications of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180), or requesting a formal letter of interpretation, please go to the Hazardous Materials Information Center (HMIC) page for contact information (phone and email address). Pending interpretation letters that are under review by the Office of Hazardous Materials Safety can be found at Pending Hazardous Materials (Hazmat) Interpretations.

Office of Pipeline Safety: A written regulatory interpretation, response to a question, or an opinion concerning a pipeline safety issue may be obtained by submitting a written request to the Office of Pipeline Safety (PHP–30), PHMSA, U.S. Department of Transportation, 1200 New Jersey Avenue SE., Washington, DC 20590–0001 or at the email address: pipeline_interp_submittal@dot.gov. In addition to email address, the requestor must include his or her return address and should also include a daytime telephone number. Requests should be submitted at least 120 days before the time the requestor needs a response. Note: electronic submission is provided as alternative to the 49 CFR Part 190.11(b) mail-in requirement.

Interpretation letters under review are available at the Office of Pipeline Safety’s Interpretation Review page. To submit comments on an interpretation under review, proceed to the Interpretation Review page, locate the interpretation to comment on, and click the appropriate link to submit a comment on the corresponding interpretation. Comment submissions will be accepted for 30-days after the interpretation letter is posted.

This section of the website below provides the ability to find regulations information including regulations parts, content of sections, and interpretations for regulations sections. A list of parts, identified by the part number and subject is also provided. To browse sections by part, click on the subject link below. You will be taken to the eCFR website to view sections for a part.

The eCFR is also searchable by keyword and other available options on the eCFR website. To search and browse regulations using the eCFR website, use the link below. For assistance, please send an email to PHMSA.Webmaster@dot.gov.

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Interpretations Reference #

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Only Chief Counsel Responses

Ref ID:	Date Sort ascending	Company Name	Individual Name	Response Document
PI-95-006	03/02/1995	Memo: Internal		View
PI-95-004	01/30/1995		D. R. Linger	View
PI-95-005	01/30/1995	U.S. Oil Company, Inc.	Thomas J. Sullivan	View
PI-95-003	01/23/1995	Memo: Internal		View
PI-95-002	01/20/1995	Memo: Internal		View
PI-95-001	01/13/1995	Memo: Internal		View
PI-94-037	12/05/1994	Shell Pipe Line Corporation	R.C. McMahan	View
PI-94-036	12/02/1994	Gullett & Associates, Inc.	Raymond J. Barone	View
PI-94-035	10/24/1994	Conoco Pipe Line Company	Dwight D. Jackson	View
PI-94-034	10/24/1994	Memo: Internal		View
PI-94-033	10/18/1994	Public Utilities Commission of Ohio	Edward M. Steele	View
PI-94-031	10/17/1994	Central Plastics Company	Jim Inhofe	View
PI-94-032	10/17/1994	BP Oil Pipeline Company	L. S. Abraham	View
PI-94-030	10/11/1994	BP Exploration (Alaska), Inc.	Barney V. Dotson	View
CHI-94-005	09/26/1994	California Environmental Projection Agency	Michael Shepard	View
CHI-94-009	08/09/1994	Electrochemical Products, Inc.		View
PI-94-027	08/04/1994	Central Plastics Company	Jim Inhofe	View
PI-94-023	06/07/1994	59 FR 29379		View
PI-94-024	06/07/1994	Railroad Commission of Texas	Mary L. McDaniel, P.E.	View
CHI-94-004	06/02/1994	Nebraska Public Power District	David G. Dales	View
PI-94-022	05/31/1994			View
PI-94-021	05/24/1994	Enron Corporation	Stanley C. Horton	View
PI-94-020	05/11/1994	Memo: Internal		View
PI-94-019	05/02/1994	Public Utilities Commission of Ohio	Edward M. Steele	View
PI-94-018	04/29/1994			View
CHI-94-003	04/19/1994	California Department of Justice	Sandra Goldberg	View
CHI-94-002	04/18/1994	Bechtel Petroleum Operations, Inc.	Steve Shire	View
PI-94-017	04/12/1994	Memo: Internal		View
PI-94-016	03/18/1994	Northern Natural Gas Company	Louis P. Soldano	View
PI-94-014	03/08/1994	BP Oil Pipeline Company	L. S. Abraham	View
PI-94-013	02/25/1994			View
CHI-94-001	02/23/1994	Swidler & Berlin	Lawrence W. Bierlein	View
PI-94-011	02/23/1994	Westpac Utilities	Anne Radomski	View
PI-94-012	02/23/1994			View
PI-94-010	02/18/1994	Memo: Internal		View
PI-94-009	02/16/1994	M. E. B. Technology	Lance Loesberg	View
PI-94-008	02/09/1994			View
PI-94-007	02/08/1994			View
PI-94-005	02/04/1994	California Public Utilities Commission	Russell W. Copeland	View
PI-94-006	02/04/1994	Alyeska Pipeline Service Company	John S. Dayton	View
PI-94-004	02/01/1994	Railroad Commission of Texas	Mary L. McDaniel, P.E	View
PI-94-003	01/26/1994			View
CHI-94-006	01/24/1994	Michigan State Police		View
CHI-94-007	01/24/1994	Minnesota Department of Transportation		View
PI-94-002	01/11/1994			View
PI-93-067	12/30/1993			View
PI-93-066	12/30/1993			View
PI-93-068	12/30/1993			View
PI-93-065	12/21/1993	Palmer Biezup & Henderson	Richard S. Tweedie	View
PI-93-064	12/07/1993	Memo: External	Department of Health and Human Services	View

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Letters of Interpretation