# 49 C.F.R. § 105.20 (2026): Guidance and interpretations

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/CFR_T49_P105_S105_20

## Section

- **Citation:** 49 C.F.R. § 105.20 (2026)
- **Heading:** Guidance and interpretations
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** Title 49 CFR: Transportation / Chapter I: PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION / Part 105: HAZARDOUS MATERIALS PROGRAM DEFINITIONS AND GENERAL PROCEDURES / Subpart B: General Procedures / § 105.20: § 105.20   Guidance and interpretations.

## Text

(a)
Hazardous materials regulations.
You can obtain information and answers to your questions on compliance with the hazardous materials regulations (49 CFR parts 171 through 180) and interpretations of those regulations by contacting PHMSA's Office of Hazardous Materials Safety as follows:
(1) Call the Hazardous Materials Information Center at 1-800-467-4922 (in Washington, DC, call (202) 366-4488). The Center is staffed from 9 a.m. through 5 p.m. Eastern time, Monday through Friday except Federal holidays. After hours, you can leave a recorded message and your call will be returned by the next business day.
(2) E-mail the Hazardous Materials Information Center at
infocntr@dot.gov.
(3) Obtain hazardous materials safety information via the Internet at
http://www.phmsa.dot.gov.
(4) Send a letter, with your return address and a daytime telephone number, to: Standards and Rulemaking Division, Pipeline and Hazardous Materials Safety Administration, Attn: PHH-10, U.S. Department of Transportation, East Building, 1200 New Jersey Avenue, SE., Washington, DC 20590-0001.
(b)
Federal hazardous materials transportation law and preemption.
You can obtain information and answers to your questions on Federal hazardous materials transportation law, 49 U.S.C. 5101
et seq.,
and Federal preemption of State, local, and Indian tribe hazardous material transportation requirements, by contacting PHMSA's Office of the Chief Counsel as follows:
(1) Call the office of the Chief Counsel at (202) 366-4400 from 9 a.m. to 5 p.m. Eastern time, Monday through Friday except Federal holidays.
(2) Access information from the Office of the Chief Counsel via the Internet at
http://www.phmsa.dot.gov.
(3) Send a letter, with your return address and a daytime telephone number, to: Office of the Chief Counsel, Pipeline and Hazardous Materials Safety Administration, Attn: PHC-10, U.S. Department of Transportation, East Building, 1200 New Jersey Avenue, SE., Washington, DC 20590-0001.
holidays.
(2) Access information from the Office of the Chief Counsel via the Internet at
http://www.phmsa.dot.gov.
(3) Send a letter, with your return address and a daytime telephone number, to: Office of the Chief Counsel, Pipeline and Hazardous Materials Safety Administration, Attn: PHC-10, U.S. Department of Transportation, East Building, 1200 New Jersey Avenue, SE., Washington, DC 20590-0001.
(4) Contact the Office of the Chief Counsel for a copy of applications for preemption determinations, waiver of preemption determinations, and inconsistency rulings received by PHMSA before February 1, 1997.
[70 FR 56087, Sept. 23, 2005, as amended at 72 FR 55682, Oct. 1, 2007; 76 FR 56310, Sept. 13, 2011]

## Nearby sections

- [49 C.F.R. § 105.15 (2026) § 105.15   Defined terms used in this subpart.](https://www.frixlaw.com/law-library/statutes/CFR_T49_P105_S105_15.md)
- [49 C.F.R. § 105.20 (2026) § 105.20   Guidance and interpretations.](https://www.frixlaw.com/law-library/statutes/CFR_T49_P105_S105_20.md)
- [49 C.F.R. § 105.25 (2026) § 105.25   Reviewing public documents.](https://www.frixlaw.com/law-library/statutes/CFR_T49_P105_S105_25.md)
- [49 C.F.R. § 105.26 (2026) § 105.26   Obtaining records on file with PHMSA.](https://www.frixlaw.com/law-library/statutes/CFR_T49_P105_S105_26.md)
- [49 C.F.R. § 105.30 (2026) § 105.30   Information made available to the public and request for confidential treatment.](https://www.frixlaw.com/law-library/statutes/CFR_T49_P105_S105_30.md)
- [49 C.F.R. § 105.35 (2026) § 105.35   Serving documents in PHMSA proceedings.](https://www.frixlaw.com/law-library/statutes/CFR_T49_P105_S105_35.md)
- [49 C.F.R. § 105.40 (2026) § 105.40   Designated agents for non-residents.](https://www.frixlaw.com/law-library/statutes/CFR_T49_P105_S105_40.md)
- [49 C.F.R. § 105.45 (2026) § 105.45   Issuing a subpoena.](https://www.frixlaw.com/law-library/statutes/CFR_T49_P105_S105_45.md)
- [49 C.F.R. § 105.50 (2026) § 105.50   Serving a subpoena.](https://www.frixlaw.com/law-library/statutes/CFR_T49_P105_S105_50.md)
- [49 C.F.R. § 105.55 (2026) § 105.55   Refusal to obey a subpoena.](https://www.frixlaw.com/law-library/statutes/CFR_T49_P105_S105_55.md)

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/CFR_T49_P105_S105_20. Check the current official text before relying on it. Not legal advice.