Shipment of marine pollutants.
Pipeline and Hazardous Materials Safety Administration · Apr 18, 2019 · Reference No. 18-0147
Interprets: 49 CFR § 171.8, 49 CFR § 171.23(b)(7), 49 CFR § 172.101, 49 CFR § 172.203(l), 49 CFR § 172.322
Reggie’s quick take
Someone asked why the rules for bulk marine pollutant packages don't cover non-bulk packages, and whether a material the IMDG Code calls "not regulated" can skip the federal rules. PHMSA says bulk packages moved under a standard other than the IMDG Code, such as the ICAO Technical Instructions, must carry the MARINE POLLUTANT mark on at least two opposite sides and meet the shipping paper rules. Non-bulk packages moved by vessel must follow the IMDG Code or the HMR. A material that meets the HMR marine pollutant definition but not the IMDG Code criteria can be excepted only if PHMSA's Associate Administrator approves it.
Written by AI (Claude) on Oct 22, 2026. Robots make mistakes and leave things out, so the letter below is what counts. Not legal advice.
April 18, 2019
Reference No. 18-0147
This letter is in response to your November 8, 2018, letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the shipment of marine pollutants.
We have paraphrased and answered your questions as follows:
Q1. You note that § 171.23(b)(7) lists requirements for specific materials transported under the International Maritime Dangerous Goods (IMDG) Code. You add that § 171.23(b)(7) requires that, except for marine pollutants transported in accordance with the IMDG Code, marine pollutants transported in bulk packages must meet the shipping paper requirements in § 172.203(l) and the marking requirements in § 172.322. You ask the rationale for this section referring only to bulk packages and not non-bulk packages.
A1. The provisions of § 171.23(b)(7) are intended to address marine pollutants transported in accordance with standards other than the IMDG Code authorized in Subpart C of Part 171. Therefore, a bulk package containing a marine pollutant transported in accordance with a standard other than the IMDG Code is subject to the requirements of § 172.203(l) and § 172.322. For example, a bulk package containing a marine pollutant transported in accordance with the International Civil Aviation Code (ICAO) Technical Instructions (TI) must to be marked with the MARINE POLLUTANT mark on at least two opposing sides even though is not a requirement of the ICAO TI. In addition, the provisions of § 171.23(b)(7) only contemplate bulk packages as non-bulk packages are not subject to the above requirements when transported by modes other than vessel. When all or part of transportation is by vessel, the non-bulk packages would be required to be transported in accordance with the IMDG Code or HMR.
Q2. You ask if “transported in accordance with the IMDG Code” means that a material shipped to the United States as “not regulated” due to it not being a marine pollutant under Section 2.9.3.4 of the IMDG Code is not subject to the HMR when transported under the IMDG Code.
A2. A material or solution that meets the definition of a marine pollutant in § 171.8 of the HMR but does not meet the criteria for a marine pollutant as provided in Sections 2.9.3.3 and 2.9.3.4 of the IMDG Code may be excepted from the requirements of the HMR as a marine pollutant if that exception is approved by the Pipeline and Hazardous Materials Safety Administration’s Associate Administrator for Hazardous Materials Safety (see § 172.101, appendix B, paragraph 5).
Sincerely,
T. Glenn Foster
Chief, Regulatory Review and Reinvention
Standards and Rulemaking Division
171.23(b)(7), 172.203(l), 172.322, 171.8, 172.101
A letter of interpretation applies the regulations to the facts the requester described. It isn’t a regulation and isn’t legal advice. The agency’s copy.