# Mr. Kent Blair — Hazardous Materials Safety Interpretation

**Citation:** 98-0553  
**Type / status:** guidance / guidance  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** Not stated  
**Published:** 1998-04-17

98-0553 concerning 177.835, 177.848.

## Document text

<<<PAGE 1>>>

of Transportation
U.S. Department
400 Seventh Street, S.W.
Research and
Washington, D.C.
20590
Special Programs
Administration
APR 1 7 1998
Mr. Kent Blair
24489 Mullin Road
Dexter, NY 13634
Dear Mr. Blair:
This is in response to your letter dated February 2, 1998, requesting clarification on the
transportation of explosives on vehicles in combination. Specifically you ask whether
Division 1.1 or 1.2 explosives may be carried on any vehicle or combination of vehicles with
any Division 2.3 (poison gas) or 6.1 (poisonous) materials under the Hazardous Materials
Regulations (HMR; 49 CFR parts 171-180).
The answer is no. Section 177.835(c) states that Division 1.1 or 1.2 materials may not be
loaded into or carried on any vehicle or a combination of vehicles if the other vehicle in the
combination contains "Division 2.3 (poisonous gas) or Division 6.1 (poisonous ) materials."
The phrase "Division 2.3 (poisonous gas) or Division 6.1 (poisonous ) materials" includes all
Division 2.3 materials, regardless of hazard zone, and all Division 6.1 material, regardless of
the physical state or packing group of the material.
I hope this satisfies your request.
Sincerely,
Delmer F. Billings
Chief, Standards Development
Office of Hazardous Materials Standards

<<<PAGE 2>>>

Sale
7=
Til 424, 35, 17848
Kent F. Blair
24489 Mullin Road
Dexter, NY 13634
February 4, 1998
Edward Mazzullo
Director
Office of Hazardous Materials Stds.
-
400 7th Street Southwest
Washington, D.C. 20590
RE: Request for clarification 49 CFR
177.835 (c) (4) (iii)
Dear Mr. Mazzullo:
The undersigned's interpretation of the regulatory
guidance contained 49 CFR 177.835 (C) (4) (iii), conflicts
with the regulatory guidance contained within 49 CFR
177.848, Segregation Table For Hazardous Materials,
specifically:
The undersigned interprets the regulatory guidance
contained within 49 CFR 177.835 (C) (4) (111) as prohibiting
DIViSIOn 1.1 O 1.2 (explosive) materials from being loaded
into or carried on any vehicle of a combination of vehicles
if the other vehicle in the combination contains any
material.
Division 2.3 (poisonous gas) or Division 6.1 (poisonous)
The term "any" is interpreted to be all inclusive,
meaning any Division 2.3 (poisonous gas), any Division 6.1
(poisonous) material, irrespective of hazard zone, physical
state (e.g. liquid) and/or packaging group assigned.
Within 49 CFR 177.848, Segregation Table For Hazardous
Materials, the listings applicable to Division 2.3
(poisonous gas) and Division 6.1 (poisonous) material is not
all inclusive. Only Poisonous gas Zone A, Poisonous gas Zone
B, and Poisonous Liquids PG I, Zone A, are considered for
the purpose of segregation during loading, storage or
transport.

<<<PAGE 3>>>

Edward Mazzullo
Director
Office of Hazardous Materials Stds.
400 7th Street Southwest
Washington, D.C. 20590
RE:
Request for clarification 49 CFR
177.835 (c) (4) (iii)
Page 2 of 2
clarification applicable to the following.
Due to the perceived conflict, respectfully request
1. With respect to 49 CFR 177.835 (c) (4) (iii), is the
intent to prohibit any Division 2.3 (poisonous gas) or
Division 6.1 (poisonous) material, irrespective of hazard
zone, physical state (e.g. liquid) and/or packaging group
assigned, from being loaded into or carried on any vehicle
of a combination of vehicles if the other vehicle in the
material ?
combination contains any Division 1.1, 1.2 (explosive)
2. If not, what specific Division 2.3 (poisonous gas)
or 6.1 (poisonous) material, (respective of hazard zone,
physical state (e.g. liquid) and/or packaging group
assigned) is prohibited from being loaded into or carried on
any vehicle of a combination of vehicles if the other
vehicle in the combination contains any Division 1.1, 1.2
(explosive) material ?
Sincerely,
Kent F. Blair

## Provenance

- Official: Yes
- Source: <https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/1998/980553.pdf>
- Source ID: `phmsa`
- SHA-256: `dd4d93789599b4bfc5f4d87fa77dda5e5efd6db4dd8cdc4fa8d1d031892a376d`
- Retrieved: 2026-08-20T00:59:31.977Z
- Exported: 2026-08-22T10:07:05.690Z
- Document slug: `phmsa-interpretation-98-0553`

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