# Mr. Kent Blair — Hazardous Materials Safety Interpretation

**Citation:** 98-0562  
**Type / status:** guidance / guidance  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** Not stated  
**Published:** 1998-04-17

98-0562 concerning 177.835, 177.848.

## Document text

<<<PAGE 1>>>

"
U.S. Department
of Transportation
400 Seventh Street. S.W.
Special Programs
Research and
Washington, D.C.
20590
Administration
APR | 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
Dangion til or le kosios on mali de ario biaty Special, you ask wehicles 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>>>

Faxe
" =°
File 37, 35175
434,
Kent F. Blair
24489 Mullin Road
Dexter, NY 13634
February 4, 1998
Edward Mazzullo
Director
400 7th Street Southwest
Office of Hazardous Materials Stds.
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
177.848, Segregation Table For Hazardous Materials,
specifically:
:
The undersigned interprets the regulatory guidance
contained within 49 CFR 177.835 (c) (4) (iii) as prohibiting
Division 1.1 or 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
state (e.g. liquid)
(poisonous) material, irrespective of hazard zone, physical
and/or packaging group assigned.
Within 49 CER 177.848, Segregation Table For Hazardous
Materials, the listings applicable to Division 2.3
(poisonous gas) and Division 6.1 (poisonous) material is not
1
all inclusive. Only Poisonous gas Zone A, Poisonous gas Zone
B, and Poisonous Liquids PG I, Zone A, are considered for
transport.
the purpose of segregation during loading, storage or

<<<PAGE 3>>>

Edward Mazzullo
Director
Office of Hazardous Materials Stds.
400 7th Street Southwest
Washington, D.C. 20590
RE: Request for clarification 49|
177.835 (c) (4) (iii)
CFR
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,
of a combination of vehicles if the other vehicle in the
from being loaded into or carried on any vehicle
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/1998/980562.pdf>
- Source ID: `phmsa`
- SHA-256: `caabc23c6b352bda0d823592ef2a5c441d86a71d09d23a2415f1d509b768b05b`
- Retrieved: 2026-08-20T00:59:31.977Z
- Exported: 2026-08-23T16:33:40.279Z
- Document slug: `phmsa-interpretation-98-0562`

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