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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 #21-0033

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

Interpretation Response Details

Response Publish Date:

Company Name: Hunter Aviation International, Inc.

Individual Name: John Lusa

Location State: NJ Country: US

View the Interpretation Document

Response text:

June 17, 2021

John Lusa
Hunter Aviation International, Inc.
2915 Ogletown Road
Newark, DE  19713

Reference No. 21-0033

Dear Mr. Lusa:

This letter is in response to your March 12, 2021, letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to cylinders containing a Division 2.2 material. Specifically, you ask whether the HMR is applicable to cylinders containing "UN1072, Oxygen, compressed, 2.2" charged to a pressure less than 200 kPa (29.0 psig/43.8 psia) at 20 °C.

As provided in § 173.115(b), the HMR defines a Division 2.2 gas—which includes oxidizing gases—as a material (or mixture) which exerts in the packaging a gauge pressure of 200 kPa (29.0 psig/43.8 psia) or greater at 20 °C (68 °F), is a liquefied gas or a cryogenic liquid, and does not meet the definition of a Division 2.1 (flammable gas) or 2.3 (gas poisonous by inhalation) material. Therefore, provided the compressed oxygen in the cylinders exert a gauge pressure of less than 200 kPa (29.0 psig/43.8 psia) in the packaging and do not meet the definition of a Division 2.1 or 2.3 material, then they are not subject to the HMR.

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


Regulation Sections

Section Subject
173.115 Class 2, Divisions 2.1, 2.2, and 2.3-Definitions