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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #22-0027

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: Entegris, Inc.

Individual Name: James V. McManus

Location State: CT Country: US

View the Interpretation Document

Response text:

September 14, 2022

Mr. James V. McManus
Senior Principal Engineer
Entegris, Inc.
7 Commerce Drive
Danbury, CT  06810

Reference No. 22-0027

Dear Mr. McManus:

This letter is in response to your March 17, 2022, letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the responsibilities of an inspector of Department of Transportation (DOT) specification cylinders. Specifically, you seek clarification regarding inspections of DOT-3AA cylinders performed in accordance with § 178.35(c) of the HMR by an Independent Inspection Agency (IIA), and whether an inspector must verify the markings required by § 178.35(f) on 100% of the cylinders listed in the Inspector’s report. You state that § 178.35(c) specifies that the inspector shall determine that each cylinder made is in conformance with the applicable specification. You further state that it is your understanding that the marking requirements in § 178.35(f) are part of the specification for DOT-3AA cylinders. Lastly, you state that in your experience as an inspector, you visually verify all marking requirements for 100% of all finished cylinders.

We have paraphrased and answered your questions as follows:

Q1. You ask whether an IIA's inspector is required to verify that markings comply with § 178.35(f) for each finished DOT-3AA cylinder listed by serial number on the Inspector's report.

A1. The answer is yes. In accordance with § 178.35(c), it is the duty of the inspector to determine that each cylinder made is in conformance with the applicable specification. Inspections shall conform to Compressed Gas Association (CGA) Pamphlet C-11, Practices for Inspection of Compressed Gas Cylinders at Time of Manufacture. Paragraph 5.2.12 in CGA C-11 states that "the inspector shall verify that the required markings have been applied to finished cylinders and are in accordance with applicable regulations."

Q2. You ask whether the word "verify" means that the inspector must visually inspect each cylinder listed on the inspector's report to ensure the markings comply with § 178.35(f) of the HMR.

A2. The answer is no. CGA C-11 states in Section 1 that "witnessing" implies a physical presence, whereas "verifying" usually involves gaining information without physical presence by examining records or statements of other persons in whom trust has been placed. Further, in paragraph 3.2.10 of CGA C-11, the word "verify" is defined as follows: “to confirm either by examination, evidence, testimony, research, demonstration, or comparison."

Q3. You ask whether it is the intent of the HMR to ensure that the markings on 100% of the cylinders are verified by the IIA's inspector.

A3. The answer is yes.

I hope this information is helpful. Please contact us if we can be of further assistance.


T. Glenn Foster
Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division

178.35(c), 178.35(f)

Regulation Sections

Section Subject
178.35 General requirements for specification cylinders