Interpretation Response #25-0117
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: Hazmat Safety Consulting, LLC
Individual Name: Robert Richard
Location State: VA Country: US
View the Interpretation Document
Response text:
January 20, 2026
Robert Richard
Vice President
Hazmat Safety Consulting, LLC
10036 Lake Occoquan Drive
Manassas, VA 20111
Reference No. 25-0117
Dear Mr. Richard
This letter is in response to your August 25, 2025 letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) regarding vessel transportation of "UN1838, Titanium tetrachloride, 6.1 (8), PG I." You state that the transportation of "UN1838," an inhalation Hazard Zone B material, will be performed using non-bulk packagings in accordance with § 173.227(b) of the HMR, a method which differs slightly from the International Maritime Dangerous Goods (IMDG) Code. It is your understanding that although the IMDG Code requires a competent authority approval (CAA) for packagings not definitively authorized in a packing instruction, the HMR may serve as the CAA in such cases. Referencing a prior letter of interpretation (Ref. No. 24-0017), you seek confirmation that a separate CAA letter is not required when this material is packaged and transported in accordance with § 173.227(b) and all other applicable HMR requirements.
Your understanding is correct. A CAA letter is not required in this scenario described in your incoming letter. Under § 178.605 of the HMR, PG I packagings intended to contain hazardous materials must be tested to a minimum test pressure of 250 kPa. The IMDG Code assigns packing instruction P602 to "UN1838." This packing instruction specifies that drums or composite packagings must comply with the 300 kPa hydrostatic test pressure requirement. Furthermore, the Hazardous Materials Table in § 172.101 refers to § 173.227 for the non-bulk packaging authorization for "UN1838." Specifically, § 173.227(b) requires compliance with packaging performance test requirements of subpart M of part 178 at the Packing Group (PG) I performance level.
Please note that a CAA, as defined in § 105.5, is an approval by the competent authority that is required under an international standard, and that a specific regulation in the HMR may be considered a CAA if it satisfies the requirement of an international standard—in this case see section 4.1.3.7 of the IMDG Code. Therefore, the authorization in the HMR for packagings in conformance with § 173.227(b) for the transportation of "UN1838" serves as a U.S. CAA.
I hope this information is helpful. Please contact us if we can be of further assistance.
Sincerely,
Dirk DerKinderen
Chief, Standards Development Branch
Standards and Rulemaking Division
§ 105.5, § 172.101, § 173.227, § 173.227(b), § 178.605