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Section §173.31: Use of tank cars

Below are the available interpretations and guidance for the given section. To return to the list of parts, use the Parts link above. If you do not see any guidance or interpretation information below, that means there is none available for the given part/section. Return to the search page to browse additional regulations sections.

PHMSA has published several Frequently Asked Questions (FAQ) documents on regulatory topics. Please review our FAQ documents below:

Additionally PHMSA has Hazardous Materials FAQs based on letters of interpretation on the following topics:

This section of the website provides the ability to find regulations information including regulations parts, content of sections, and interpretations for regulations sections. Below is a list of parts, identified by the part number and subject. 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.

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: 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.

The regulations text of the section can be found on the eCFR website. To view the regulations text, use the link below. For assistance, please send an email to

View section 173.31 on the ECFR website

Interpretation Responses

Ref ID Date Company Name Individual Name Response Document
22-0138 AllTranstek, L.L.C. Mike Tait View
19-0117 Railway Supply Institute (RSI) Mr. E. Michael O'Malley View
18-0032 INEOS Phenol David Rodgers View
99-0313 Chemical Manufacturers Association Mr. Randy Speight View
07-0136 Bolds & Associates, LLC Mr. James J. Bolds      View
13-0202 Midland Rail Services, LLC Mr. Allen Maty View
10-0104 Wacker Polymers Mr. Edwin McIntyre View
14-0206 Port of Tucson Mr. Bryan Slagle View
15-0031R Mr. Joe Connelly View
15-0031 Specialty Transportation and Regulatory Services Mr. Joe Connelly View
14-0175 Linde Mr. John P. Smith PE View
15-0139 A.I.D. Inc. Mr. Donald Brittingham View
08-0127 Ecolab, Inc. Mr. Stephen V. Schulte View
00-0066 Allied Universal Corp. Ms. Robin J. Eddy View
06-0058 Ferreilgas Mr. Ross Warnell View
99-0249 FMC Corporation Mr. Ralph J. Mikida View
99-0066 Transportation Safety Degussa Corporation Mr. John Foglio View
99-0166 Albemarle Corporation Jack E. Helms, Ph.D, P.E View
09-0064 C & N Companies Mr. Jon Bjornstad View
04-0008 Koch Mineral Services, LLC Mr. Stephen P. Nowicki View
05-0014 Mr. Richard Daley Borden Chemical, Inc. View
14-0092 Mr. Ben Sweat View
05-0109 GATX Rail Mr. Doug Mullins View
99-0196 Solvay Interox, Inc. Mark A. Feldman, Ph.D., CQ Mgr View
13-0055 Health, Environment, and Safety Arkema Ms. Christina Kurtz View
06-0198 DuPont Global Logistics Mr. Kevin M. Greene View