# Massachusetts State Police — Hazardous Materials Safety Interpretation

- **operation:** document
- **citation:** 21-0060
- **title:** Massachusetts State Police — Hazardous Materials Safety Interpretation
- **source type:** guidance
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** guidance
- **official:** true
- **published on:** 2021-09-28
- **effective on:** Not available
- **summary:** 21-0060 response to Massachusetts State Police concerning 171.8, 173.32.
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- **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-21-0060.md
- **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-21-0060
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/75976/210060.pdf
**body:**

<<<PAGE 1>>>

U.S. Department
of Transportation
Pipeline and Hazardous
Materials Safety
Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
September 28, 2021
Trooper Scott Maguire
Massachusetts State Police
906 Elm Street
Concord, MA 01742
Reference No. 21-0060
Dear Mr. Maguire:
This letter is in response to your May 25, 2021, email requesting clarification of the Hazardous
Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to portable tanks and cargo
tanks. We have paraphrased and answered your questions as follows:
Q1. You ask whether it is permissible to weld a specification Department of Transportation
(DOT) 51 portable tank to a chassis and convert it to a cargo tank motor vehicle (CTMV)
for the transportation of liquefied petroleum gas (LPG).
A1. The answer is no. The definition of a “cargo tank” as specified in § 171.8 of the HMR
does not authorize a bulk packaging that is fabricated to the specification of a portable
tank. Additionally, the HMR defines a CTMV as a “motor vehicle with one or more
cargo tanks permanently attached to or forming an integral part of the motor vehicle.”
Therefore, a DOT 51 portable tank which has been permanently attached to a motor
vehicle would not constitute a CTMV as the tank is not an integral part of the motor
vehicle.
Q2. You ask whether a specification DOT 51 portable tank retains its specification after being
permanently attached to a vehicle.
A2. The answer is no. The portable tank as described in your inquiry was originally
fabricated as a specification DOT 51 portable tank. However, once the specification
DOT 51 portable tank was permanently attached to the motor vehicle, it no longer meets
the definition of a “portable tank” as defined in § 171.8. Therefore, the specification
DOT 51 portable tank loses its specification because it can no longer be defined as a
“portable tank.” See Answer A1.

<<<PAGE 2>>>

Q3. You ask whether § 173.32(a)(3) applies to both specification and non-specification
portable tanks.
A3. The answer is yes. The use of portable tank requirements in § 173.32(a)(3) can apply to
both specification and non-specification portable tanks.
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 3>>>

Andrews
21-0060
From: INFOCNTR (PHMSA)
To: Dodd, Alice (PHMSA)
Cc: Hazmat Interps
Subject: FW: Letter of Interpretation
Date: Thursday, May 27, 2021 4:32:04 PM
Attachments: PT Interp Request.docx
Hi Alice,
Please see the attached LOI request.
Below, is the mailing address and phone number for the inquirer.
Please let me know if you need anything else.
Regards,
-Breanna
---------------------------------------------
Scott Maguire
PO Box 9
Millbury, MA 01527-0009
508.259.0875
From: Maguire, Scott (POL) [mailto:scott.maguire@state.ma.us]
Sent: Tuesday, May 25, 2021 3:10 PM
To: INFOCNTR (PHMSA) <INFOCNTR.INFOCNTR@dot.gov>
Subject: Letter of Interpretation
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.
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