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Section §173.4: Small quantities for highway and rail

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 173.4 on the ECFR website

Interpretation Responses

Ref ID Date Company Name Individual Name Response Document
18-0018 BCB International Ltd Paul Ames View
18-0013 Environmental Resource Center Kristie Absher View
18-0011 Currie Associates Barbara Konrad View
17-0105 HAMATEAM, Inc Paul Dambek View
17-0070 Entegris Mr. Quentin Yarbrough View
17-0138 Labelmaster Jim Shimko View
15-0140 Inmark Packaging Mr. Jay Johnson View
11-0165R Thermofisher Ms. Melissa Russell View
15-0140 Inmark Packaging Mr. Jay Jonson
11-0165R Thermofisher Ms. Melissa Russell View
09-0113 Murphy Industries Ms. Alecia Rice View
02-0092 SENSIDYNE Ron Roberson View
08-0195 LaMotte Co. Ms. Irene Penfield View
05-0283 Transportation Development Group Mr. Jim Powell View
08-0002 Kajuligan Corporation Mr. Clifford E. Croft View
15-0075 Dexsil Corporation Mr. Andrew Lynn View
02-0237 Remel Inc. Ramsey Division Richard Sher View
15-0050 URS Corporation Mr. Andrew Romach View
00-0044 Photographic Solutions, Inc. Mr. David M. Stone View
01-0184 Statlab Medical Product Mr. John Bickel View
01-0106 Antimicrobial Division Mr. James P. Ringo View
98-0111 Department of Environmental Quality Mr. Daniel Schultz View
12-0128 SGS North America Mr. Terry M. Thompson View
12-0047 Robertshaw Industrial Products Ms. Natalie Pike View
98-0502 Department of the Army Ms. Marcia C. Davies, Ph.D View
08-0223 High Q LLC Mr. Scott Bischoff View
99-0001 Sharp Microelectronics Technology, Inc. Ms. Lesa L. Grant View
06-0269 Inmark, Inc. Mr. Junius "Jay" Johnson  View
09-0094 Roche Molecular Systems, Inc. Ms. Julie Park View
98-0310 Law Offices of F. Michael Friedman Mr. F. Michael Friedman View
03-0256 The RxFire Company Mr. Peter Nopper View
08-0182 ACCO Brands Corporation Mr. Darren Lenox View
01-0101 BD Preanalytical Solutions Ms. M. Wendy Bosshardt View
06-0241 LND, Inc. Mr. Spencer B. Neyland View
09-0266 Argonne National Laboratory Mr. John Pearson View
09-0175 California Department of Fish and Game Mr. Charles R. Todd View
99-0116 Stored Energy Concepts, Inc. Mr. Richard E. Lisowski View
02-0256 Keller and Heckman, LLP Terrence D. Jones, Esq View
07-0079 National Institute of Standards and Technology Mr. Larry Lucas  View
07-0160 Charkit Chemical Corporation Mr. Steve J. Catania View
09-0069 Thermo Fisher Scientific Mr. Gene Sanders View
04-0189 Retrotec Inc. Mr. Carl Piehl View
09-0259 Revance Therapeutics, Inc. Mr. Philip Perotti View
04-0040 University of California, Irvine
Environmental Health and Safety
Mr. Younghans-Haug View
11-0068 P&G Mr. Alvin J. Bernstein View
07-0054 FedEx Express Mr. Marvin A. Sudduth View
16-0096 Mr. Douglas Shaw View
09-0042 Thermo Fisher Scientific, Customer Channels Group Mr. Gene Sanders View
13-0056 UPS Mr. Matthew Maslanka View
08-0163 ACCO Brands Corporation Mr. Darren Lenox View
06-0247 DelValCo Consultants Mr. George M. Thorpe View
10-0072 Transportation Development Group Mr. Jim Powell View
06-0239 Severn Trent Laboratories, Inc. Mr. William J. Geibel View