# ABC Nitrogen Service Corp — Hazardous Materials Safety Interpretation

- **operation:** document
- **citation:** 24-0007
- **title:** ABC Nitrogen Service Corp — Hazardous Materials Safety Interpretation
- **source type:** guidance
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** guidance
- **official:** true
- **published on:** 2024-03-27
- **effective on:** Not available
- **summary:** 24-0007 response to ABC Nitrogen Service Corp concerning 171.8, 173.320.
- **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-24-0007.json
- **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-24-0007.md
- **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-24-0007
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/2024-03/240007.pdf
**body:**

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U.S. Department
of Transportation
Pipeline and Hazardous
Materials Safety
Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
March 27, 2024
Aimee Fontenot
DOT Coordinator
ABC Nitrogen Service Corp
11425 I-10 East
Baytown, TX 77523
Reference No. 24-0007
Dear Ms. Fontenot:
This letter is in response to your January 26, 2024, email requesting clarification of the
Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to placarding
requirements for transportation of nitrogen, refrigerated liquid (cryogenic liquid). You state that
your company transports nitrogen in insulated cargo tanks designed and constructed so that the
pressure in such packagings will not exceed 25.3 psig under ambient temperature conditions
during transportation in accordance with § 173.320(a). It is your understanding that this
transportation is excepted from certain requirements of the HMR. Specifically, you ask whether
hazard placards are required on insulated cargo tanks that transport “UN1977, Nitrogen,
refrigerated liquid cryogenic liquid, 2.2” in this manner.
The answer is no. Placards are not required on the insulated cargo tanks used for carriage of
“UN1977, Nitrogen, refrigerated liquid cryogenic liquid, 2.2” when transported in accordance
with the conditions of § 173.320(a). The exceptions contained in § 173.320 are applicable to the
transportation by motor vehicle and railcar of “atmospheric gases” such as nitrogen—see
§ 171.8—and helium, cryogenic liquids, in select packagings, including insulated cargo tanks,
designed and constructed so that the pressure in such packagings will not exceed 25.3 psig
under ambient temperature conditions during transportation. This includes exception from the
Part 172, Supbart F placarding requirements of the HMR.
I hope you find this information helpful. Please contact us if we can be of further assistance.
Sincerely,
Dirk Der Kinderen
Chief, Standards Development Branch
Standards and Rulemaking Division

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Roundtree
24-0007
From: Roundtree, Taurean (PHMSA)
To: Dodd, Alice (PHMSA)
Cc: DerKinderen, Dirk (PHMSA)
Subject: FW: 173.320 - LOI request
Date: Friday, February 2, 2024 11:26:10 AM
Attachments: image002.png
Good morning Alice,
This email came in last week and we attempted to answer via phone/email with a
previously issued letter, but the requestor would like a letter that is addressed to
their company. The original request is at the bottom of this message, and I am
including her contact information as well. I have spoken Dirk we have agreed to
draft a letter, could you please enter the request into FileMaker and assign it to
me.
Requestor title and contact info:
Aimee Fontenot
DOT Coordinator
ABC Nitrogen Service Corp
11425 I-10 East
Baytown, Texas 77523
832-790-9279
Thank you,
Taurean Roundtree
Transportation Specialist
United States Department of Transportation
Pipeline and Hazardous Materials Safety Administration
(771) 216-4118 (cell)
From: Cardez, Eugenio (PHMSA) <Eugenio.cardez@dot.gov>
Sent: Friday, January 26, 2024 12:58 PM
To: Roundtree, Taurean (PHMSA) <Taurean.Roundtree@dot.gov>
Cc: DerKinderen, Dirk (PHMSA) <Dirk.DerKinderen@dot.gov>; Nickels, Matthew (PHMSA)
<Matthew.Nickels@dot.gov>
Subject: FW: 173.320
Hey Taurean,
Would you mind taking an initial try with this one and see if we can maybe handle by phone. If they

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still want to request a letter we’ll move it to Alice for formal processing. We can have a chat before
you reaching out to them and go over your findings if you’d like.
Thanks,
Eugenio
From: Raynor, T'Mia (PHMSA) <t'mia.raynor@dot.gov>
Sent: Friday, January 26, 2024 12:21 PM
To: Hazmat Interps <hazmatinterps@dot.gov>
Subject: FW: 173.320
Good Afternoon,
Would someone from the team be able to assist the user below?
Thanks,
T’Mia Raynor
Webmaster, Office of the PHMSA CIO
US Department of Transportation
Pipeline and Hazardous Materials Safety Administration
1200 New Jersey Ave. SE, Washington, D.C., 20590
Office: 202.366.9818 ◊ Mobile: 202.580.9447
PHMSA Home | LinkedIn | Twitter | HAZMAT | OPS
From: Aimee Fontenot <aimee@abcnitrogen.net>
Sent: Friday, January 26, 2024 12:20 PM
To: PHMSA Website Manager <PHMSAWebsiteManager@dot.gov>
Subject: 173.320
CAUTION: This email originated from outside of the Department of Transportation (DOT). Do
not click on links or open attachments unless you recognize the sender and know the content
is safe.
Good Morning,
I write you today with a formal request for a formal letter of interpretation regarding the
applicability of the cryogenic exemption under section 173.320 for placarding purposes.
Our organization transports Nitrogen in insulated cargo tankers that are designed and
constructed so that the pressure will not exceed 25.3 psig under ambient temperature
conditions during transportation. We seemed to be challenged on the exemption by police

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and Dot officers on the road about not having a Hazmat Placard. Can you please give me a
formal interpretation of the exemption as it pertains to transporting N2 by tanker stating if or
if not required to have a hazmat placard, or any placard other than the UN 1977.
Thank you in advance for your time and consideration.
Aimee Fontenot
ABC Nitrogen
832-790-7979
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