# Hunter Aviation International, Inc. — Hazardous Materials Safety Interpretation

- **operation:** document
- **citation:** 21-0033
- **title:** Hunter Aviation International, Inc. — Hazardous Materials Safety Interpretation
- **source type:** guidance
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** guidance
- **official:** true
- **published on:** 2021-06-17
- **effective on:** Not available
- **summary:** 21-0033 response to Hunter Aviation International, Inc. concerning 173.115.
- **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-21-0033.json
- **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-21-0033.md
- **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-21-0033
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/75246/210033.pdf
**body:**

<<<PAGE 1>>>

U.S. Department
of Transportation
Pipeline and Hazardous
Materials Safety
Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
June 17, 2021
Mr. 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 does not meet the definition of a
Division 2.1 or 2.3 material, they are not subject to the HMR.
I hope this information is helpful. Please contact us if we can be of further assistance.
Sincerely,
T. Glenn Foster
Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division

<<<PAGE 2>>>

HUNTER AVIATION INTERNATIONAL, INC
Wolcott
2915 OGLETOWN ROAD
NEWARK, DE 19713 U.S.A.
21-0033
(418) 875-5111 (418) 875-2999 FAX
DUNS# 020857222
Friday, March 12, 2021
Mr. Shane Kelley
Director, Standards and Rulemaking Division
U.S. DOT/PHMSA (PHH-10)
1200 New Jersey Avenue, SE East Building, 2nd Floor
Washington, DC 20590
Dear Mr. Kelley
We operate a fleet of 1950's era Hawker Hunter Fighter jets. The pilot's oxygen cylinders in our
jets were manufactured to British MOD standard 647 and are maintained according to an FAA
approved inspection program.
In some instances, it would be preferrable to ship these cylinders with slight residual pressure (<
200 kPA) to avoid possible corrosion or contamination. Does the HMR apply to the transportation
of a Division 2.2 and 5.1 gas having a pressure in a container below 200 kPa (29.0 psig/43.8 psia)?
In the DOT response 09-0264 it states: "PHMSA revised the definition in § 173.115(b)(1) for a
Division 2.2 gas in final rules issued on January 14,2009 and January 4, 2010. Section 173.115(b)
states a Division 2.2 gas is a nonflammable, non-poisonous compressed gas that includes
compressed gas, liquefied gas, pressurized cryogenic gas, compressed gas in solution, asphyxiant
gas, and oxidizing gas. Therefore, as amended, a Division 2.2 gas, including one with an oxidizer
subsidiary hazard, is one that exerts a gauge pressure on a packaging of at least 200 kPa at 20°C
(68 OF). In accordance with the revised definition, after January 1, 2010, a cylinder of oxygen gas
that exerts a gauge pressure less than 200 kPa at 20°C is not subject to the HMR. "
Does the above hold true today? Can we ship our pilot oxygen cylinders as not subject to the HMR
when at a pressure below 200kPA?
Sincerely,
John Lusa
General Manager
Encl: 09-0264
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